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c906108c | 1 | \input texinfo @c -*-texinfo-*- |
c02a867d | 2 | @c Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, |
9d2897ad | 3 | @c 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
c906108c SS |
4 | @c Free Software Foundation, Inc. |
5 | @c | |
5d161b24 | 6 | @c %**start of header |
c906108c SS |
7 | @c makeinfo ignores cmds prev to setfilename, so its arg cannot make use |
8 | @c of @set vars. However, you can override filename with makeinfo -o. | |
9 | @setfilename gdb.info | |
10 | @c | |
11 | @include gdb-cfg.texi | |
12 | @c | |
c906108c | 13 | @settitle Debugging with @value{GDBN} |
c906108c SS |
14 | @setchapternewpage odd |
15 | @c %**end of header | |
16 | ||
17 | @iftex | |
18 | @c @smallbook | |
19 | @c @cropmarks | |
20 | @end iftex | |
21 | ||
22 | @finalout | |
23 | @syncodeindex ky cp | |
89c73ade | 24 | @syncodeindex tp cp |
c906108c | 25 | |
41afff9a | 26 | @c readline appendices use @vindex, @findex and @ftable, |
48e934c6 | 27 | @c annotate.texi and gdbmi use @findex. |
c906108c | 28 | @syncodeindex vr cp |
41afff9a | 29 | @syncodeindex fn cp |
c906108c SS |
30 | |
31 | @c !!set GDB manual's edition---not the same as GDB version! | |
9fe8321b | 32 | @c This is updated by GNU Press. |
e9c75b65 | 33 | @set EDITION Ninth |
c906108c | 34 | |
87885426 FN |
35 | @c !!set GDB edit command default editor |
36 | @set EDITOR /bin/ex | |
c906108c | 37 | |
6c0e9fb3 | 38 | @c THIS MANUAL REQUIRES TEXINFO 4.0 OR LATER. |
c906108c | 39 | |
c906108c | 40 | @c This is a dir.info fragment to support semi-automated addition of |
6d2ebf8b | 41 | @c manuals to an info tree. |
03727ca6 | 42 | @dircategory Software development |
96a2c332 | 43 | @direntry |
03727ca6 | 44 | * Gdb: (gdb). The GNU debugger. |
96a2c332 SS |
45 | @end direntry |
46 | ||
a67ec3f4 JM |
47 | @copying |
48 | Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, | |
9d2897ad | 49 | 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
a67ec3f4 | 50 | Free Software Foundation, Inc. |
c906108c | 51 | |
e9c75b65 EZ |
52 | Permission is granted to copy, distribute and/or modify this document |
53 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
54 | any later version published by the Free Software Foundation; with the | |
959acfd1 EZ |
55 | Invariant Sections being ``Free Software'' and ``Free Software Needs |
56 | Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' | |
57 | and with the Back-Cover Texts as in (a) below. | |
c906108c | 58 | |
b8533aec DJ |
59 | (a) The FSF's Back-Cover Text is: ``You are free to copy and modify |
60 | this GNU Manual. Buying copies from GNU Press supports the FSF in | |
61 | developing GNU and promoting software freedom.'' | |
a67ec3f4 JM |
62 | @end copying |
63 | ||
64 | @ifnottex | |
65 | This file documents the @sc{gnu} debugger @value{GDBN}. | |
66 | ||
67 | This is the @value{EDITION} Edition, of @cite{Debugging with | |
68 | @value{GDBN}: the @sc{gnu} Source-Level Debugger} for @value{GDBN} | |
69 | @ifset VERSION_PACKAGE | |
70 | @value{VERSION_PACKAGE} | |
71 | @end ifset | |
72 | Version @value{GDBVN}. | |
73 | ||
74 | @insertcopying | |
75 | @end ifnottex | |
c906108c SS |
76 | |
77 | @titlepage | |
78 | @title Debugging with @value{GDBN} | |
79 | @subtitle The @sc{gnu} Source-Level Debugger | |
c906108c | 80 | @sp 1 |
c906108c | 81 | @subtitle @value{EDITION} Edition, for @value{GDBN} version @value{GDBVN} |
c16158bc JM |
82 | @ifset VERSION_PACKAGE |
83 | @sp 1 | |
84 | @subtitle @value{VERSION_PACKAGE} | |
85 | @end ifset | |
9e9c5ae7 | 86 | @author Richard Stallman, Roland Pesch, Stan Shebs, et al. |
c906108c | 87 | @page |
c906108c SS |
88 | @tex |
89 | {\parskip=0pt | |
c16158bc | 90 | \hfill (Send bugs and comments on @value{GDBN} to @value{BUGURL}.)\par |
c906108c SS |
91 | \hfill {\it Debugging with @value{GDBN}}\par |
92 | \hfill \TeX{}info \texinfoversion\par | |
93 | } | |
94 | @end tex | |
53a5351d | 95 | |
c906108c | 96 | @vskip 0pt plus 1filll |
c906108c | 97 | Published by the Free Software Foundation @* |
c02a867d EZ |
98 | 51 Franklin Street, Fifth Floor, |
99 | Boston, MA 02110-1301, USA@* | |
6d2ebf8b | 100 | ISBN 1-882114-77-9 @* |
e9c75b65 | 101 | |
a67ec3f4 | 102 | @insertcopying |
3fb6a982 JB |
103 | @page |
104 | This edition of the GDB manual is dedicated to the memory of Fred | |
105 | Fish. Fred was a long-standing contributor to GDB and to Free | |
106 | software in general. We will miss him. | |
c906108c SS |
107 | @end titlepage |
108 | @page | |
109 | ||
6c0e9fb3 | 110 | @ifnottex |
6d2ebf8b SS |
111 | @node Top, Summary, (dir), (dir) |
112 | ||
c906108c SS |
113 | @top Debugging with @value{GDBN} |
114 | ||
115 | This file describes @value{GDBN}, the @sc{gnu} symbolic debugger. | |
116 | ||
c16158bc JM |
117 | This is the @value{EDITION} Edition, for @value{GDBN} |
118 | @ifset VERSION_PACKAGE | |
119 | @value{VERSION_PACKAGE} | |
120 | @end ifset | |
121 | Version @value{GDBVN}. | |
c906108c | 122 | |
9d2897ad | 123 | Copyright (C) 1988-2010 Free Software Foundation, Inc. |
6d2ebf8b | 124 | |
3fb6a982 JB |
125 | This edition of the GDB manual is dedicated to the memory of Fred |
126 | Fish. Fred was a long-standing contributor to GDB and to Free | |
127 | software in general. We will miss him. | |
128 | ||
6d2ebf8b SS |
129 | @menu |
130 | * Summary:: Summary of @value{GDBN} | |
131 | * Sample Session:: A sample @value{GDBN} session | |
132 | ||
133 | * Invocation:: Getting in and out of @value{GDBN} | |
134 | * Commands:: @value{GDBN} commands | |
135 | * Running:: Running programs under @value{GDBN} | |
136 | * Stopping:: Stopping and continuing | |
bacec72f | 137 | * Reverse Execution:: Running programs backward |
a2311334 | 138 | * Process Record and Replay:: Recording inferior's execution and replaying it |
6d2ebf8b SS |
139 | * Stack:: Examining the stack |
140 | * Source:: Examining source files | |
141 | * Data:: Examining data | |
edb3359d | 142 | * Optimized Code:: Debugging optimized code |
e2e0bcd1 | 143 | * Macros:: Preprocessor Macros |
b37052ae | 144 | * Tracepoints:: Debugging remote targets non-intrusively |
df0cd8c5 | 145 | * Overlays:: Debugging programs that use overlays |
6d2ebf8b SS |
146 | |
147 | * Languages:: Using @value{GDBN} with different languages | |
148 | ||
149 | * Symbols:: Examining the symbol table | |
150 | * Altering:: Altering execution | |
151 | * GDB Files:: @value{GDBN} files | |
152 | * Targets:: Specifying a debugging target | |
6b2f586d | 153 | * Remote Debugging:: Debugging remote programs |
6d2ebf8b SS |
154 | * Configurations:: Configuration-specific information |
155 | * Controlling GDB:: Controlling @value{GDBN} | |
d57a3c85 | 156 | * Extending GDB:: Extending @value{GDBN} |
21c294e6 | 157 | * Interpreters:: Command Interpreters |
c8f4133a | 158 | * TUI:: @value{GDBN} Text User Interface |
6d2ebf8b | 159 | * Emacs:: Using @value{GDBN} under @sc{gnu} Emacs |
7162c0ca | 160 | * GDB/MI:: @value{GDBN}'s Machine Interface. |
c8f4133a | 161 | * Annotations:: @value{GDBN}'s annotation interface. |
4efc6507 | 162 | * JIT Interface:: Using the JIT debugging interface. |
6d2ebf8b SS |
163 | |
164 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
6d2ebf8b SS |
165 | |
166 | * Command Line Editing:: Command Line Editing | |
167 | * Using History Interactively:: Using History Interactively | |
0869d01b | 168 | * Formatting Documentation:: How to format and print @value{GDBN} documentation |
6d2ebf8b | 169 | * Installing GDB:: Installing GDB |
eb12ee30 | 170 | * Maintenance Commands:: Maintenance Commands |
e0ce93ac | 171 | * Remote Protocol:: GDB Remote Serial Protocol |
f418dd93 | 172 | * Agent Expressions:: The GDB Agent Expression Mechanism |
23181151 DJ |
173 | * Target Descriptions:: How targets can describe themselves to |
174 | @value{GDBN} | |
07e059b5 VP |
175 | * Operating System Information:: Getting additional information from |
176 | the operating system | |
aab4e0ec AC |
177 | * Copying:: GNU General Public License says |
178 | how you can copy and share GDB | |
6826cf00 | 179 | * GNU Free Documentation License:: The license for this documentation |
6d2ebf8b SS |
180 | * Index:: Index |
181 | @end menu | |
182 | ||
6c0e9fb3 | 183 | @end ifnottex |
c906108c | 184 | |
449f3b6c | 185 | @contents |
449f3b6c | 186 | |
6d2ebf8b | 187 | @node Summary |
c906108c SS |
188 | @unnumbered Summary of @value{GDBN} |
189 | ||
190 | The purpose of a debugger such as @value{GDBN} is to allow you to see what is | |
191 | going on ``inside'' another program while it executes---or what another | |
192 | program was doing at the moment it crashed. | |
193 | ||
194 | @value{GDBN} can do four main kinds of things (plus other things in support of | |
195 | these) to help you catch bugs in the act: | |
196 | ||
197 | @itemize @bullet | |
198 | @item | |
199 | Start your program, specifying anything that might affect its behavior. | |
200 | ||
201 | @item | |
202 | Make your program stop on specified conditions. | |
203 | ||
204 | @item | |
205 | Examine what has happened, when your program has stopped. | |
206 | ||
207 | @item | |
208 | Change things in your program, so you can experiment with correcting the | |
209 | effects of one bug and go on to learn about another. | |
210 | @end itemize | |
211 | ||
49efadf5 | 212 | You can use @value{GDBN} to debug programs written in C and C@t{++}. |
79a6e687 | 213 | For more information, see @ref{Supported Languages,,Supported Languages}. |
c906108c SS |
214 | For more information, see @ref{C,,C and C++}. |
215 | ||
cce74817 | 216 | @cindex Modula-2 |
e632838e AC |
217 | Support for Modula-2 is partial. For information on Modula-2, see |
218 | @ref{Modula-2,,Modula-2}. | |
c906108c | 219 | |
cce74817 JM |
220 | @cindex Pascal |
221 | Debugging Pascal programs which use sets, subranges, file variables, or | |
222 | nested functions does not currently work. @value{GDBN} does not support | |
223 | entering expressions, printing values, or similar features using Pascal | |
224 | syntax. | |
c906108c | 225 | |
c906108c SS |
226 | @cindex Fortran |
227 | @value{GDBN} can be used to debug programs written in Fortran, although | |
53a5351d | 228 | it may be necessary to refer to some variables with a trailing |
cce74817 | 229 | underscore. |
c906108c | 230 | |
b37303ee AF |
231 | @value{GDBN} can be used to debug programs written in Objective-C, |
232 | using either the Apple/NeXT or the GNU Objective-C runtime. | |
233 | ||
c906108c SS |
234 | @menu |
235 | * Free Software:: Freely redistributable software | |
236 | * Contributors:: Contributors to GDB | |
237 | @end menu | |
238 | ||
6d2ebf8b | 239 | @node Free Software |
79a6e687 | 240 | @unnumberedsec Free Software |
c906108c | 241 | |
5d161b24 | 242 | @value{GDBN} is @dfn{free software}, protected by the @sc{gnu} |
c906108c SS |
243 | General Public License |
244 | (GPL). The GPL gives you the freedom to copy or adapt a licensed | |
245 | program---but every person getting a copy also gets with it the | |
246 | freedom to modify that copy (which means that they must get access to | |
247 | the source code), and the freedom to distribute further copies. | |
248 | Typical software companies use copyrights to limit your freedoms; the | |
249 | Free Software Foundation uses the GPL to preserve these freedoms. | |
250 | ||
251 | Fundamentally, the General Public License is a license which says that | |
252 | you have these freedoms and that you cannot take these freedoms away | |
253 | from anyone else. | |
254 | ||
2666264b | 255 | @unnumberedsec Free Software Needs Free Documentation |
959acfd1 EZ |
256 | |
257 | The biggest deficiency in the free software community today is not in | |
258 | the software---it is the lack of good free documentation that we can | |
259 | include with the free software. Many of our most important | |
260 | programs do not come with free reference manuals and free introductory | |
261 | texts. Documentation is an essential part of any software package; | |
262 | when an important free software package does not come with a free | |
263 | manual and a free tutorial, that is a major gap. We have many such | |
264 | gaps today. | |
265 | ||
266 | Consider Perl, for instance. The tutorial manuals that people | |
267 | normally use are non-free. How did this come about? Because the | |
268 | authors of those manuals published them with restrictive terms---no | |
269 | copying, no modification, source files not available---which exclude | |
270 | them from the free software world. | |
271 | ||
272 | That wasn't the first time this sort of thing happened, and it was far | |
273 | from the last. Many times we have heard a GNU user eagerly describe a | |
274 | manual that he is writing, his intended contribution to the community, | |
275 | only to learn that he had ruined everything by signing a publication | |
276 | contract to make it non-free. | |
277 | ||
278 | Free documentation, like free software, is a matter of freedom, not | |
279 | price. The problem with the non-free manual is not that publishers | |
280 | charge a price for printed copies---that in itself is fine. (The Free | |
281 | Software Foundation sells printed copies of manuals, too.) The | |
282 | problem is the restrictions on the use of the manual. Free manuals | |
283 | are available in source code form, and give you permission to copy and | |
284 | modify. Non-free manuals do not allow this. | |
285 | ||
286 | The criteria of freedom for a free manual are roughly the same as for | |
287 | free software. Redistribution (including the normal kinds of | |
288 | commercial redistribution) must be permitted, so that the manual can | |
289 | accompany every copy of the program, both on-line and on paper. | |
290 | ||
291 | Permission for modification of the technical content is crucial too. | |
292 | When people modify the software, adding or changing features, if they | |
293 | are conscientious they will change the manual too---so they can | |
294 | provide accurate and clear documentation for the modified program. A | |
295 | manual that leaves you no choice but to write a new manual to document | |
296 | a changed version of the program is not really available to our | |
297 | community. | |
298 | ||
299 | Some kinds of limits on the way modification is handled are | |
300 | acceptable. For example, requirements to preserve the original | |
301 | author's copyright notice, the distribution terms, or the list of | |
302 | authors, are ok. It is also no problem to require modified versions | |
303 | to include notice that they were modified. Even entire sections that | |
304 | may not be deleted or changed are acceptable, as long as they deal | |
305 | with nontechnical topics (like this one). These kinds of restrictions | |
306 | are acceptable because they don't obstruct the community's normal use | |
307 | of the manual. | |
308 | ||
309 | However, it must be possible to modify all the @emph{technical} | |
310 | content of the manual, and then distribute the result in all the usual | |
311 | media, through all the usual channels. Otherwise, the restrictions | |
312 | obstruct the use of the manual, it is not free, and we need another | |
313 | manual to replace it. | |
314 | ||
315 | Please spread the word about this issue. Our community continues to | |
316 | lose manuals to proprietary publishing. If we spread the word that | |
317 | free software needs free reference manuals and free tutorials, perhaps | |
318 | the next person who wants to contribute by writing documentation will | |
319 | realize, before it is too late, that only free manuals contribute to | |
320 | the free software community. | |
321 | ||
322 | If you are writing documentation, please insist on publishing it under | |
323 | the GNU Free Documentation License or another free documentation | |
324 | license. Remember that this decision requires your approval---you | |
325 | don't have to let the publisher decide. Some commercial publishers | |
326 | will use a free license if you insist, but they will not propose the | |
327 | option; it is up to you to raise the issue and say firmly that this is | |
328 | what you want. If the publisher you are dealing with refuses, please | |
329 | try other publishers. If you're not sure whether a proposed license | |
42584a72 | 330 | is free, write to @email{licensing@@gnu.org}. |
959acfd1 EZ |
331 | |
332 | You can encourage commercial publishers to sell more free, copylefted | |
333 | manuals and tutorials by buying them, and particularly by buying | |
334 | copies from the publishers that paid for their writing or for major | |
335 | improvements. Meanwhile, try to avoid buying non-free documentation | |
336 | at all. Check the distribution terms of a manual before you buy it, | |
337 | and insist that whoever seeks your business must respect your freedom. | |
72c9928d EZ |
338 | Check the history of the book, and try to reward the publishers that |
339 | have paid or pay the authors to work on it. | |
959acfd1 EZ |
340 | |
341 | The Free Software Foundation maintains a list of free documentation | |
342 | published by other publishers, at | |
343 | @url{http://www.fsf.org/doc/other-free-books.html}. | |
344 | ||
6d2ebf8b | 345 | @node Contributors |
96a2c332 SS |
346 | @unnumberedsec Contributors to @value{GDBN} |
347 | ||
348 | Richard Stallman was the original author of @value{GDBN}, and of many | |
349 | other @sc{gnu} programs. Many others have contributed to its | |
350 | development. This section attempts to credit major contributors. One | |
351 | of the virtues of free software is that everyone is free to contribute | |
352 | to it; with regret, we cannot actually acknowledge everyone here. The | |
353 | file @file{ChangeLog} in the @value{GDBN} distribution approximates a | |
c906108c SS |
354 | blow-by-blow account. |
355 | ||
356 | Changes much prior to version 2.0 are lost in the mists of time. | |
357 | ||
358 | @quotation | |
359 | @emph{Plea:} Additions to this section are particularly welcome. If you | |
360 | or your friends (or enemies, to be evenhanded) have been unfairly | |
361 | omitted from this list, we would like to add your names! | |
362 | @end quotation | |
363 | ||
364 | So that they may not regard their many labors as thankless, we | |
365 | particularly thank those who shepherded @value{GDBN} through major | |
366 | releases: | |
7ba3cf9c | 367 | Andrew Cagney (releases 6.3, 6.2, 6.1, 6.0, 5.3, 5.2, 5.1 and 5.0); |
c906108c SS |
368 | Jim Blandy (release 4.18); |
369 | Jason Molenda (release 4.17); | |
370 | Stan Shebs (release 4.14); | |
371 | Fred Fish (releases 4.16, 4.15, 4.13, 4.12, 4.11, 4.10, and 4.9); | |
372 | Stu Grossman and John Gilmore (releases 4.8, 4.7, 4.6, 4.5, and 4.4); | |
373 | John Gilmore (releases 4.3, 4.2, 4.1, 4.0, and 3.9); | |
374 | Jim Kingdon (releases 3.5, 3.4, and 3.3); | |
375 | and Randy Smith (releases 3.2, 3.1, and 3.0). | |
376 | ||
377 | Richard Stallman, assisted at various times by Peter TerMaat, Chris | |
378 | Hanson, and Richard Mlynarik, handled releases through 2.8. | |
379 | ||
b37052ae EZ |
380 | Michael Tiemann is the author of most of the @sc{gnu} C@t{++} support |
381 | in @value{GDBN}, with significant additional contributions from Per | |
382 | Bothner and Daniel Berlin. James Clark wrote the @sc{gnu} C@t{++} | |
383 | demangler. Early work on C@t{++} was by Peter TerMaat (who also did | |
384 | much general update work leading to release 3.0). | |
c906108c | 385 | |
b37052ae | 386 | @value{GDBN} uses the BFD subroutine library to examine multiple |
c906108c SS |
387 | object-file formats; BFD was a joint project of David V. |
388 | Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore. | |
389 | ||
390 | David Johnson wrote the original COFF support; Pace Willison did | |
391 | the original support for encapsulated COFF. | |
392 | ||
0179ffac | 393 | Brent Benson of Harris Computer Systems contributed DWARF 2 support. |
c906108c SS |
394 | |
395 | Adam de Boor and Bradley Davis contributed the ISI Optimum V support. | |
396 | Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS | |
397 | support. | |
398 | Jean-Daniel Fekete contributed Sun 386i support. | |
399 | Chris Hanson improved the HP9000 support. | |
400 | Noboyuki Hikichi and Tomoyuki Hasei contributed Sony/News OS 3 support. | |
401 | David Johnson contributed Encore Umax support. | |
402 | Jyrki Kuoppala contributed Altos 3068 support. | |
403 | Jeff Law contributed HP PA and SOM support. | |
404 | Keith Packard contributed NS32K support. | |
405 | Doug Rabson contributed Acorn Risc Machine support. | |
406 | Bob Rusk contributed Harris Nighthawk CX-UX support. | |
407 | Chris Smith contributed Convex support (and Fortran debugging). | |
408 | Jonathan Stone contributed Pyramid support. | |
409 | Michael Tiemann contributed SPARC support. | |
410 | Tim Tucker contributed support for the Gould NP1 and Gould Powernode. | |
411 | Pace Willison contributed Intel 386 support. | |
412 | Jay Vosburgh contributed Symmetry support. | |
a37295f9 | 413 | Marko Mlinar contributed OpenRISC 1000 support. |
c906108c | 414 | |
1104b9e7 | 415 | Andreas Schwab contributed M68K @sc{gnu}/Linux support. |
c906108c SS |
416 | |
417 | Rich Schaefer and Peter Schauer helped with support of SunOS shared | |
418 | libraries. | |
419 | ||
420 | Jay Fenlason and Roland McGrath ensured that @value{GDBN} and GAS agree | |
421 | about several machine instruction sets. | |
422 | ||
423 | Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped develop | |
424 | remote debugging. Intel Corporation, Wind River Systems, AMD, and ARM | |
425 | contributed remote debugging modules for the i960, VxWorks, A29K UDI, | |
426 | and RDI targets, respectively. | |
427 | ||
428 | Brian Fox is the author of the readline libraries providing | |
429 | command-line editing and command history. | |
430 | ||
7a292a7a SS |
431 | Andrew Beers of SUNY Buffalo wrote the language-switching code, the |
432 | Modula-2 support, and contributed the Languages chapter of this manual. | |
c906108c | 433 | |
5d161b24 | 434 | Fred Fish wrote most of the support for Unix System Vr4. |
b37052ae | 435 | He also enhanced the command-completion support to cover C@t{++} overloaded |
c906108c | 436 | symbols. |
c906108c | 437 | |
f24c5e49 KI |
438 | Hitachi America (now Renesas America), Ltd. sponsored the support for |
439 | H8/300, H8/500, and Super-H processors. | |
c906108c SS |
440 | |
441 | NEC sponsored the support for the v850, Vr4xxx, and Vr5xxx processors. | |
442 | ||
f24c5e49 KI |
443 | Mitsubishi (now Renesas) sponsored the support for D10V, D30V, and M32R/D |
444 | processors. | |
c906108c SS |
445 | |
446 | Toshiba sponsored the support for the TX39 Mips processor. | |
447 | ||
448 | Matsushita sponsored the support for the MN10200 and MN10300 processors. | |
449 | ||
96a2c332 | 450 | Fujitsu sponsored the support for SPARClite and FR30 processors. |
c906108c SS |
451 | |
452 | Kung Hsu, Jeff Law, and Rick Sladkey added support for hardware | |
453 | watchpoints. | |
454 | ||
455 | Michael Snyder added support for tracepoints. | |
456 | ||
457 | Stu Grossman wrote gdbserver. | |
458 | ||
459 | Jim Kingdon, Peter Schauer, Ian Taylor, and Stu Grossman made | |
96a2c332 | 460 | nearly innumerable bug fixes and cleanups throughout @value{GDBN}. |
c906108c SS |
461 | |
462 | The following people at the Hewlett-Packard Company contributed | |
463 | support for the PA-RISC 2.0 architecture, HP-UX 10.20, 10.30, and 11.0 | |
b37052ae | 464 | (narrow mode), HP's implementation of kernel threads, HP's aC@t{++} |
d0d5df6f AC |
465 | compiler, and the Text User Interface (nee Terminal User Interface): |
466 | Ben Krepp, Richard Title, John Bishop, Susan Macchia, Kathy Mann, | |
467 | Satish Pai, India Paul, Steve Rehrauer, and Elena Zannoni. Kim Haase | |
468 | provided HP-specific information in this manual. | |
c906108c | 469 | |
b37052ae EZ |
470 | DJ Delorie ported @value{GDBN} to MS-DOS, for the DJGPP project. |
471 | Robert Hoehne made significant contributions to the DJGPP port. | |
472 | ||
96a2c332 SS |
473 | Cygnus Solutions has sponsored @value{GDBN} maintenance and much of its |
474 | development since 1991. Cygnus engineers who have worked on @value{GDBN} | |
2df3850c JM |
475 | fulltime include Mark Alexander, Jim Blandy, Per Bothner, Kevin |
476 | Buettner, Edith Epstein, Chris Faylor, Fred Fish, Martin Hunt, Jim | |
477 | Ingham, John Gilmore, Stu Grossman, Kung Hsu, Jim Kingdon, John Metzler, | |
478 | Fernando Nasser, Geoffrey Noer, Dawn Perchik, Rich Pixley, Zdenek | |
479 | Radouch, Keith Seitz, Stan Shebs, David Taylor, and Elena Zannoni. In | |
480 | addition, Dave Brolley, Ian Carmichael, Steve Chamberlain, Nick Clifton, | |
481 | JT Conklin, Stan Cox, DJ Delorie, Ulrich Drepper, Frank Eigler, Doug | |
482 | Evans, Sean Fagan, David Henkel-Wallace, Richard Henderson, Jeff | |
483 | Holcomb, Jeff Law, Jim Lemke, Tom Lord, Bob Manson, Michael Meissner, | |
484 | Jason Merrill, Catherine Moore, Drew Moseley, Ken Raeburn, Gavin | |
485 | Romig-Koch, Rob Savoye, Jamie Smith, Mike Stump, Ian Taylor, Angela | |
486 | Thomas, Michael Tiemann, Tom Tromey, Ron Unrau, Jim Wilson, and David | |
487 | Zuhn have made contributions both large and small. | |
c906108c | 488 | |
ffed4509 AC |
489 | Andrew Cagney, Fernando Nasser, and Elena Zannoni, while working for |
490 | Cygnus Solutions, implemented the original @sc{gdb/mi} interface. | |
491 | ||
e2e0bcd1 JB |
492 | Jim Blandy added support for preprocessor macros, while working for Red |
493 | Hat. | |
c906108c | 494 | |
a9967aef AC |
495 | Andrew Cagney designed @value{GDBN}'s architecture vector. Many |
496 | people including Andrew Cagney, Stephane Carrez, Randolph Chung, Nick | |
497 | Duffek, Richard Henderson, Mark Kettenis, Grace Sainsbury, Kei | |
498 | Sakamoto, Yoshinori Sato, Michael Snyder, Andreas Schwab, Jason | |
499 | Thorpe, Corinna Vinschen, Ulrich Weigand, and Elena Zannoni, helped | |
500 | with the migration of old architectures to this new framework. | |
501 | ||
c5e30d01 AC |
502 | Andrew Cagney completely re-designed and re-implemented @value{GDBN}'s |
503 | unwinder framework, this consisting of a fresh new design featuring | |
504 | frame IDs, independent frame sniffers, and the sentinel frame. Mark | |
505 | Kettenis implemented the @sc{dwarf 2} unwinder, Jeff Johnston the | |
506 | libunwind unwinder, and Andrew Cagney the dummy, sentinel, tramp, and | |
db2e3e2e | 507 | trad unwinders. The architecture-specific changes, each involving a |
c5e30d01 AC |
508 | complete rewrite of the architecture's frame code, were carried out by |
509 | Jim Blandy, Joel Brobecker, Kevin Buettner, Andrew Cagney, Stephane | |
510 | Carrez, Randolph Chung, Orjan Friberg, Richard Henderson, Daniel | |
511 | Jacobowitz, Jeff Johnston, Mark Kettenis, Theodore A. Roth, Kei | |
512 | Sakamoto, Yoshinori Sato, Michael Snyder, Corinna Vinschen, and Ulrich | |
513 | Weigand. | |
514 | ||
ca3bf3bd DJ |
515 | Christian Zankel, Ross Morley, Bob Wilson, and Maxim Grigoriev from |
516 | Tensilica, Inc.@: contributed support for Xtensa processors. Others | |
517 | who have worked on the Xtensa port of @value{GDBN} in the past include | |
518 | Steve Tjiang, John Newlin, and Scott Foehner. | |
519 | ||
08be9d71 ME |
520 | Michael Eager and staff of Xilinx, Inc., contributed support for the |
521 | Xilinx MicroBlaze architecture. | |
522 | ||
6d2ebf8b | 523 | @node Sample Session |
c906108c SS |
524 | @chapter A Sample @value{GDBN} Session |
525 | ||
526 | You can use this manual at your leisure to read all about @value{GDBN}. | |
527 | However, a handful of commands are enough to get started using the | |
528 | debugger. This chapter illustrates those commands. | |
529 | ||
530 | @iftex | |
531 | In this sample session, we emphasize user input like this: @b{input}, | |
532 | to make it easier to pick out from the surrounding output. | |
533 | @end iftex | |
534 | ||
535 | @c FIXME: this example may not be appropriate for some configs, where | |
536 | @c FIXME...primary interest is in remote use. | |
537 | ||
538 | One of the preliminary versions of @sc{gnu} @code{m4} (a generic macro | |
539 | processor) exhibits the following bug: sometimes, when we change its | |
540 | quote strings from the default, the commands used to capture one macro | |
541 | definition within another stop working. In the following short @code{m4} | |
542 | session, we define a macro @code{foo} which expands to @code{0000}; we | |
543 | then use the @code{m4} built-in @code{defn} to define @code{bar} as the | |
544 | same thing. However, when we change the open quote string to | |
545 | @code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same | |
546 | procedure fails to define a new synonym @code{baz}: | |
547 | ||
548 | @smallexample | |
549 | $ @b{cd gnu/m4} | |
550 | $ @b{./m4} | |
551 | @b{define(foo,0000)} | |
552 | ||
553 | @b{foo} | |
554 | 0000 | |
555 | @b{define(bar,defn(`foo'))} | |
556 | ||
557 | @b{bar} | |
558 | 0000 | |
559 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
560 | ||
561 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
562 | @b{baz} | |
c8aa23ab | 563 | @b{Ctrl-d} |
c906108c SS |
564 | m4: End of input: 0: fatal error: EOF in string |
565 | @end smallexample | |
566 | ||
567 | @noindent | |
568 | Let us use @value{GDBN} to try to see what is going on. | |
569 | ||
c906108c SS |
570 | @smallexample |
571 | $ @b{@value{GDBP} m4} | |
572 | @c FIXME: this falsifies the exact text played out, to permit smallbook | |
573 | @c FIXME... format to come out better. | |
574 | @value{GDBN} is free software and you are welcome to distribute copies | |
5d161b24 | 575 | of it under certain conditions; type "show copying" to see |
c906108c | 576 | the conditions. |
5d161b24 | 577 | There is absolutely no warranty for @value{GDBN}; type "show warranty" |
c906108c SS |
578 | for details. |
579 | ||
580 | @value{GDBN} @value{GDBVN}, Copyright 1999 Free Software Foundation, Inc... | |
581 | (@value{GDBP}) | |
582 | @end smallexample | |
c906108c SS |
583 | |
584 | @noindent | |
585 | @value{GDBN} reads only enough symbol data to know where to find the | |
586 | rest when needed; as a result, the first prompt comes up very quickly. | |
587 | We now tell @value{GDBN} to use a narrower display width than usual, so | |
588 | that examples fit in this manual. | |
589 | ||
590 | @smallexample | |
591 | (@value{GDBP}) @b{set width 70} | |
592 | @end smallexample | |
593 | ||
594 | @noindent | |
595 | We need to see how the @code{m4} built-in @code{changequote} works. | |
596 | Having looked at the source, we know the relevant subroutine is | |
597 | @code{m4_changequote}, so we set a breakpoint there with the @value{GDBN} | |
598 | @code{break} command. | |
599 | ||
600 | @smallexample | |
601 | (@value{GDBP}) @b{break m4_changequote} | |
602 | Breakpoint 1 at 0x62f4: file builtin.c, line 879. | |
603 | @end smallexample | |
604 | ||
605 | @noindent | |
606 | Using the @code{run} command, we start @code{m4} running under @value{GDBN} | |
607 | control; as long as control does not reach the @code{m4_changequote} | |
608 | subroutine, the program runs as usual: | |
609 | ||
610 | @smallexample | |
611 | (@value{GDBP}) @b{run} | |
612 | Starting program: /work/Editorial/gdb/gnu/m4/m4 | |
613 | @b{define(foo,0000)} | |
614 | ||
615 | @b{foo} | |
616 | 0000 | |
617 | @end smallexample | |
618 | ||
619 | @noindent | |
620 | To trigger the breakpoint, we call @code{changequote}. @value{GDBN} | |
621 | suspends execution of @code{m4}, displaying information about the | |
622 | context where it stops. | |
623 | ||
624 | @smallexample | |
625 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
626 | ||
5d161b24 | 627 | Breakpoint 1, m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
628 | at builtin.c:879 |
629 | 879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]),argc,1,3)) | |
630 | @end smallexample | |
631 | ||
632 | @noindent | |
633 | Now we use the command @code{n} (@code{next}) to advance execution to | |
634 | the next line of the current function. | |
635 | ||
636 | @smallexample | |
637 | (@value{GDBP}) @b{n} | |
638 | 882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\ | |
639 | : nil, | |
640 | @end smallexample | |
641 | ||
642 | @noindent | |
643 | @code{set_quotes} looks like a promising subroutine. We can go into it | |
644 | by using the command @code{s} (@code{step}) instead of @code{next}. | |
645 | @code{step} goes to the next line to be executed in @emph{any} | |
646 | subroutine, so it steps into @code{set_quotes}. | |
647 | ||
648 | @smallexample | |
649 | (@value{GDBP}) @b{s} | |
650 | set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
651 | at input.c:530 | |
652 | 530 if (lquote != def_lquote) | |
653 | @end smallexample | |
654 | ||
655 | @noindent | |
656 | The display that shows the subroutine where @code{m4} is now | |
657 | suspended (and its arguments) is called a stack frame display. It | |
658 | shows a summary of the stack. We can use the @code{backtrace} | |
659 | command (which can also be spelled @code{bt}), to see where we are | |
660 | in the stack as a whole: the @code{backtrace} command displays a | |
661 | stack frame for each active subroutine. | |
662 | ||
663 | @smallexample | |
664 | (@value{GDBP}) @b{bt} | |
665 | #0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
666 | at input.c:530 | |
5d161b24 | 667 | #1 0x6344 in m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
668 | at builtin.c:882 |
669 | #2 0x8174 in expand_macro (sym=0x33320) at macro.c:242 | |
670 | #3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30) | |
671 | at macro.c:71 | |
672 | #4 0x79dc in expand_input () at macro.c:40 | |
673 | #5 0x2930 in main (argc=0, argv=0xf7fffb20) at m4.c:195 | |
674 | @end smallexample | |
675 | ||
676 | @noindent | |
677 | We step through a few more lines to see what happens. The first two | |
678 | times, we can use @samp{s}; the next two times we use @code{n} to avoid | |
679 | falling into the @code{xstrdup} subroutine. | |
680 | ||
681 | @smallexample | |
682 | (@value{GDBP}) @b{s} | |
683 | 0x3b5c 532 if (rquote != def_rquote) | |
684 | (@value{GDBP}) @b{s} | |
685 | 0x3b80 535 lquote = (lq == nil || *lq == '\0') ? \ | |
686 | def_lquote : xstrdup(lq); | |
687 | (@value{GDBP}) @b{n} | |
688 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
689 | : xstrdup(rq); | |
690 | (@value{GDBP}) @b{n} | |
691 | 538 len_lquote = strlen(rquote); | |
692 | @end smallexample | |
693 | ||
694 | @noindent | |
695 | The last line displayed looks a little odd; we can examine the variables | |
696 | @code{lquote} and @code{rquote} to see if they are in fact the new left | |
697 | and right quotes we specified. We use the command @code{p} | |
698 | (@code{print}) to see their values. | |
699 | ||
700 | @smallexample | |
701 | (@value{GDBP}) @b{p lquote} | |
702 | $1 = 0x35d40 "<QUOTE>" | |
703 | (@value{GDBP}) @b{p rquote} | |
704 | $2 = 0x35d50 "<UNQUOTE>" | |
705 | @end smallexample | |
706 | ||
707 | @noindent | |
708 | @code{lquote} and @code{rquote} are indeed the new left and right quotes. | |
709 | To look at some context, we can display ten lines of source | |
710 | surrounding the current line with the @code{l} (@code{list}) command. | |
711 | ||
712 | @smallexample | |
713 | (@value{GDBP}) @b{l} | |
714 | 533 xfree(rquote); | |
715 | 534 | |
716 | 535 lquote = (lq == nil || *lq == '\0') ? def_lquote\ | |
717 | : xstrdup (lq); | |
718 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
719 | : xstrdup (rq); | |
720 | 537 | |
721 | 538 len_lquote = strlen(rquote); | |
722 | 539 len_rquote = strlen(lquote); | |
723 | 540 @} | |
724 | 541 | |
725 | 542 void | |
726 | @end smallexample | |
727 | ||
728 | @noindent | |
729 | Let us step past the two lines that set @code{len_lquote} and | |
730 | @code{len_rquote}, and then examine the values of those variables. | |
731 | ||
732 | @smallexample | |
733 | (@value{GDBP}) @b{n} | |
734 | 539 len_rquote = strlen(lquote); | |
735 | (@value{GDBP}) @b{n} | |
736 | 540 @} | |
737 | (@value{GDBP}) @b{p len_lquote} | |
738 | $3 = 9 | |
739 | (@value{GDBP}) @b{p len_rquote} | |
740 | $4 = 7 | |
741 | @end smallexample | |
742 | ||
743 | @noindent | |
744 | That certainly looks wrong, assuming @code{len_lquote} and | |
745 | @code{len_rquote} are meant to be the lengths of @code{lquote} and | |
746 | @code{rquote} respectively. We can set them to better values using | |
747 | the @code{p} command, since it can print the value of | |
748 | any expression---and that expression can include subroutine calls and | |
749 | assignments. | |
750 | ||
751 | @smallexample | |
752 | (@value{GDBP}) @b{p len_lquote=strlen(lquote)} | |
753 | $5 = 7 | |
754 | (@value{GDBP}) @b{p len_rquote=strlen(rquote)} | |
755 | $6 = 9 | |
756 | @end smallexample | |
757 | ||
758 | @noindent | |
759 | Is that enough to fix the problem of using the new quotes with the | |
760 | @code{m4} built-in @code{defn}? We can allow @code{m4} to continue | |
761 | executing with the @code{c} (@code{continue}) command, and then try the | |
762 | example that caused trouble initially: | |
763 | ||
764 | @smallexample | |
765 | (@value{GDBP}) @b{c} | |
766 | Continuing. | |
767 | ||
768 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
769 | ||
770 | baz | |
771 | 0000 | |
772 | @end smallexample | |
773 | ||
774 | @noindent | |
775 | Success! The new quotes now work just as well as the default ones. The | |
776 | problem seems to have been just the two typos defining the wrong | |
777 | lengths. We allow @code{m4} exit by giving it an EOF as input: | |
778 | ||
779 | @smallexample | |
c8aa23ab | 780 | @b{Ctrl-d} |
c906108c SS |
781 | Program exited normally. |
782 | @end smallexample | |
783 | ||
784 | @noindent | |
785 | The message @samp{Program exited normally.} is from @value{GDBN}; it | |
786 | indicates @code{m4} has finished executing. We can end our @value{GDBN} | |
787 | session with the @value{GDBN} @code{quit} command. | |
788 | ||
789 | @smallexample | |
790 | (@value{GDBP}) @b{quit} | |
791 | @end smallexample | |
c906108c | 792 | |
6d2ebf8b | 793 | @node Invocation |
c906108c SS |
794 | @chapter Getting In and Out of @value{GDBN} |
795 | ||
796 | This chapter discusses how to start @value{GDBN}, and how to get out of it. | |
5d161b24 | 797 | The essentials are: |
c906108c | 798 | @itemize @bullet |
5d161b24 | 799 | @item |
53a5351d | 800 | type @samp{@value{GDBP}} to start @value{GDBN}. |
5d161b24 | 801 | @item |
c8aa23ab | 802 | type @kbd{quit} or @kbd{Ctrl-d} to exit. |
c906108c SS |
803 | @end itemize |
804 | ||
805 | @menu | |
806 | * Invoking GDB:: How to start @value{GDBN} | |
807 | * Quitting GDB:: How to quit @value{GDBN} | |
808 | * Shell Commands:: How to use shell commands inside @value{GDBN} | |
79a6e687 | 809 | * Logging Output:: How to log @value{GDBN}'s output to a file |
c906108c SS |
810 | @end menu |
811 | ||
6d2ebf8b | 812 | @node Invoking GDB |
c906108c SS |
813 | @section Invoking @value{GDBN} |
814 | ||
c906108c SS |
815 | Invoke @value{GDBN} by running the program @code{@value{GDBP}}. Once started, |
816 | @value{GDBN} reads commands from the terminal until you tell it to exit. | |
817 | ||
818 | You can also run @code{@value{GDBP}} with a variety of arguments and options, | |
819 | to specify more of your debugging environment at the outset. | |
820 | ||
c906108c SS |
821 | The command-line options described here are designed |
822 | to cover a variety of situations; in some environments, some of these | |
5d161b24 | 823 | options may effectively be unavailable. |
c906108c SS |
824 | |
825 | The most usual way to start @value{GDBN} is with one argument, | |
826 | specifying an executable program: | |
827 | ||
474c8240 | 828 | @smallexample |
c906108c | 829 | @value{GDBP} @var{program} |
474c8240 | 830 | @end smallexample |
c906108c | 831 | |
c906108c SS |
832 | @noindent |
833 | You can also start with both an executable program and a core file | |
834 | specified: | |
835 | ||
474c8240 | 836 | @smallexample |
c906108c | 837 | @value{GDBP} @var{program} @var{core} |
474c8240 | 838 | @end smallexample |
c906108c SS |
839 | |
840 | You can, instead, specify a process ID as a second argument, if you want | |
841 | to debug a running process: | |
842 | ||
474c8240 | 843 | @smallexample |
c906108c | 844 | @value{GDBP} @var{program} 1234 |
474c8240 | 845 | @end smallexample |
c906108c SS |
846 | |
847 | @noindent | |
848 | would attach @value{GDBN} to process @code{1234} (unless you also have a file | |
849 | named @file{1234}; @value{GDBN} does check for a core file first). | |
850 | ||
c906108c | 851 | Taking advantage of the second command-line argument requires a fairly |
2df3850c JM |
852 | complete operating system; when you use @value{GDBN} as a remote |
853 | debugger attached to a bare board, there may not be any notion of | |
854 | ``process'', and there is often no way to get a core dump. @value{GDBN} | |
855 | will warn you if it is unable to attach or to read core dumps. | |
c906108c | 856 | |
aa26fa3a TT |
857 | You can optionally have @code{@value{GDBP}} pass any arguments after the |
858 | executable file to the inferior using @code{--args}. This option stops | |
859 | option processing. | |
474c8240 | 860 | @smallexample |
3f94c067 | 861 | @value{GDBP} --args gcc -O2 -c foo.c |
474c8240 | 862 | @end smallexample |
aa26fa3a TT |
863 | This will cause @code{@value{GDBP}} to debug @code{gcc}, and to set |
864 | @code{gcc}'s command-line arguments (@pxref{Arguments}) to @samp{-O2 -c foo.c}. | |
865 | ||
96a2c332 | 866 | You can run @code{@value{GDBP}} without printing the front material, which describes |
c906108c SS |
867 | @value{GDBN}'s non-warranty, by specifying @code{-silent}: |
868 | ||
869 | @smallexample | |
870 | @value{GDBP} -silent | |
871 | @end smallexample | |
872 | ||
873 | @noindent | |
874 | You can further control how @value{GDBN} starts up by using command-line | |
875 | options. @value{GDBN} itself can remind you of the options available. | |
876 | ||
877 | @noindent | |
878 | Type | |
879 | ||
474c8240 | 880 | @smallexample |
c906108c | 881 | @value{GDBP} -help |
474c8240 | 882 | @end smallexample |
c906108c SS |
883 | |
884 | @noindent | |
885 | to display all available options and briefly describe their use | |
886 | (@samp{@value{GDBP} -h} is a shorter equivalent). | |
887 | ||
888 | All options and command line arguments you give are processed | |
889 | in sequential order. The order makes a difference when the | |
890 | @samp{-x} option is used. | |
891 | ||
892 | ||
893 | @menu | |
c906108c SS |
894 | * File Options:: Choosing files |
895 | * Mode Options:: Choosing modes | |
6fc08d32 | 896 | * Startup:: What @value{GDBN} does during startup |
c906108c SS |
897 | @end menu |
898 | ||
6d2ebf8b | 899 | @node File Options |
79a6e687 | 900 | @subsection Choosing Files |
c906108c | 901 | |
2df3850c | 902 | When @value{GDBN} starts, it reads any arguments other than options as |
c906108c SS |
903 | specifying an executable file and core file (or process ID). This is |
904 | the same as if the arguments were specified by the @samp{-se} and | |
d52fb0e9 | 905 | @samp{-c} (or @samp{-p}) options respectively. (@value{GDBN} reads the |
19837790 MS |
906 | first argument that does not have an associated option flag as |
907 | equivalent to the @samp{-se} option followed by that argument; and the | |
908 | second argument that does not have an associated option flag, if any, as | |
909 | equivalent to the @samp{-c}/@samp{-p} option followed by that argument.) | |
910 | If the second argument begins with a decimal digit, @value{GDBN} will | |
911 | first attempt to attach to it as a process, and if that fails, attempt | |
912 | to open it as a corefile. If you have a corefile whose name begins with | |
b383017d | 913 | a digit, you can prevent @value{GDBN} from treating it as a pid by |
c1468174 | 914 | prefixing it with @file{./}, e.g.@: @file{./12345}. |
7a292a7a SS |
915 | |
916 | If @value{GDBN} has not been configured to included core file support, | |
917 | such as for most embedded targets, then it will complain about a second | |
918 | argument and ignore it. | |
c906108c SS |
919 | |
920 | Many options have both long and short forms; both are shown in the | |
921 | following list. @value{GDBN} also recognizes the long forms if you truncate | |
922 | them, so long as enough of the option is present to be unambiguous. | |
923 | (If you prefer, you can flag option arguments with @samp{--} rather | |
924 | than @samp{-}, though we illustrate the more usual convention.) | |
925 | ||
d700128c EZ |
926 | @c NOTE: the @cindex entries here use double dashes ON PURPOSE. This |
927 | @c way, both those who look for -foo and --foo in the index, will find | |
928 | @c it. | |
929 | ||
c906108c SS |
930 | @table @code |
931 | @item -symbols @var{file} | |
932 | @itemx -s @var{file} | |
d700128c EZ |
933 | @cindex @code{--symbols} |
934 | @cindex @code{-s} | |
c906108c SS |
935 | Read symbol table from file @var{file}. |
936 | ||
937 | @item -exec @var{file} | |
938 | @itemx -e @var{file} | |
d700128c EZ |
939 | @cindex @code{--exec} |
940 | @cindex @code{-e} | |
7a292a7a SS |
941 | Use file @var{file} as the executable file to execute when appropriate, |
942 | and for examining pure data in conjunction with a core dump. | |
c906108c SS |
943 | |
944 | @item -se @var{file} | |
d700128c | 945 | @cindex @code{--se} |
c906108c SS |
946 | Read symbol table from file @var{file} and use it as the executable |
947 | file. | |
948 | ||
c906108c SS |
949 | @item -core @var{file} |
950 | @itemx -c @var{file} | |
d700128c EZ |
951 | @cindex @code{--core} |
952 | @cindex @code{-c} | |
b383017d | 953 | Use file @var{file} as a core dump to examine. |
c906108c | 954 | |
19837790 MS |
955 | @item -pid @var{number} |
956 | @itemx -p @var{number} | |
957 | @cindex @code{--pid} | |
958 | @cindex @code{-p} | |
959 | Connect to process ID @var{number}, as with the @code{attach} command. | |
c906108c SS |
960 | |
961 | @item -command @var{file} | |
962 | @itemx -x @var{file} | |
d700128c EZ |
963 | @cindex @code{--command} |
964 | @cindex @code{-x} | |
c906108c SS |
965 | Execute @value{GDBN} commands from file @var{file}. @xref{Command |
966 | Files,, Command files}. | |
967 | ||
8a5a3c82 AS |
968 | @item -eval-command @var{command} |
969 | @itemx -ex @var{command} | |
970 | @cindex @code{--eval-command} | |
971 | @cindex @code{-ex} | |
972 | Execute a single @value{GDBN} command. | |
973 | ||
974 | This option may be used multiple times to call multiple commands. It may | |
975 | also be interleaved with @samp{-command} as required. | |
976 | ||
977 | @smallexample | |
978 | @value{GDBP} -ex 'target sim' -ex 'load' \ | |
979 | -x setbreakpoints -ex 'run' a.out | |
980 | @end smallexample | |
981 | ||
c906108c SS |
982 | @item -directory @var{directory} |
983 | @itemx -d @var{directory} | |
d700128c EZ |
984 | @cindex @code{--directory} |
985 | @cindex @code{-d} | |
4b505b12 | 986 | Add @var{directory} to the path to search for source and script files. |
c906108c | 987 | |
c906108c SS |
988 | @item -r |
989 | @itemx -readnow | |
d700128c EZ |
990 | @cindex @code{--readnow} |
991 | @cindex @code{-r} | |
c906108c SS |
992 | Read each symbol file's entire symbol table immediately, rather than |
993 | the default, which is to read it incrementally as it is needed. | |
994 | This makes startup slower, but makes future operations faster. | |
53a5351d | 995 | |
c906108c SS |
996 | @end table |
997 | ||
6d2ebf8b | 998 | @node Mode Options |
79a6e687 | 999 | @subsection Choosing Modes |
c906108c SS |
1000 | |
1001 | You can run @value{GDBN} in various alternative modes---for example, in | |
1002 | batch mode or quiet mode. | |
1003 | ||
1004 | @table @code | |
1005 | @item -nx | |
1006 | @itemx -n | |
d700128c EZ |
1007 | @cindex @code{--nx} |
1008 | @cindex @code{-n} | |
96565e91 | 1009 | Do not execute commands found in any initialization files. Normally, |
2df3850c JM |
1010 | @value{GDBN} executes the commands in these files after all the command |
1011 | options and arguments have been processed. @xref{Command Files,,Command | |
79a6e687 | 1012 | Files}. |
c906108c SS |
1013 | |
1014 | @item -quiet | |
d700128c | 1015 | @itemx -silent |
c906108c | 1016 | @itemx -q |
d700128c EZ |
1017 | @cindex @code{--quiet} |
1018 | @cindex @code{--silent} | |
1019 | @cindex @code{-q} | |
c906108c SS |
1020 | ``Quiet''. Do not print the introductory and copyright messages. These |
1021 | messages are also suppressed in batch mode. | |
1022 | ||
1023 | @item -batch | |
d700128c | 1024 | @cindex @code{--batch} |
c906108c SS |
1025 | Run in batch mode. Exit with status @code{0} after processing all the |
1026 | command files specified with @samp{-x} (and all commands from | |
1027 | initialization files, if not inhibited with @samp{-n}). Exit with | |
1028 | nonzero status if an error occurs in executing the @value{GDBN} commands | |
1029 | in the command files. | |
1030 | ||
2df3850c JM |
1031 | Batch mode may be useful for running @value{GDBN} as a filter, for |
1032 | example to download and run a program on another computer; in order to | |
1033 | make this more useful, the message | |
c906108c | 1034 | |
474c8240 | 1035 | @smallexample |
c906108c | 1036 | Program exited normally. |
474c8240 | 1037 | @end smallexample |
c906108c SS |
1038 | |
1039 | @noindent | |
2df3850c JM |
1040 | (which is ordinarily issued whenever a program running under |
1041 | @value{GDBN} control terminates) is not issued when running in batch | |
1042 | mode. | |
1043 | ||
1a088d06 AS |
1044 | @item -batch-silent |
1045 | @cindex @code{--batch-silent} | |
1046 | Run in batch mode exactly like @samp{-batch}, but totally silently. All | |
1047 | @value{GDBN} output to @code{stdout} is prevented (@code{stderr} is | |
1048 | unaffected). This is much quieter than @samp{-silent} and would be useless | |
1049 | for an interactive session. | |
1050 | ||
1051 | This is particularly useful when using targets that give @samp{Loading section} | |
1052 | messages, for example. | |
1053 | ||
1054 | Note that targets that give their output via @value{GDBN}, as opposed to | |
1055 | writing directly to @code{stdout}, will also be made silent. | |
1056 | ||
4b0ad762 AS |
1057 | @item -return-child-result |
1058 | @cindex @code{--return-child-result} | |
1059 | The return code from @value{GDBN} will be the return code from the child | |
1060 | process (the process being debugged), with the following exceptions: | |
1061 | ||
1062 | @itemize @bullet | |
1063 | @item | |
1064 | @value{GDBN} exits abnormally. E.g., due to an incorrect argument or an | |
1065 | internal error. In this case the exit code is the same as it would have been | |
1066 | without @samp{-return-child-result}. | |
1067 | @item | |
1068 | The user quits with an explicit value. E.g., @samp{quit 1}. | |
1069 | @item | |
1070 | The child process never runs, or is not allowed to terminate, in which case | |
1071 | the exit code will be -1. | |
1072 | @end itemize | |
1073 | ||
1074 | This option is useful in conjunction with @samp{-batch} or @samp{-batch-silent}, | |
1075 | when @value{GDBN} is being used as a remote program loader or simulator | |
1076 | interface. | |
1077 | ||
2df3850c JM |
1078 | @item -nowindows |
1079 | @itemx -nw | |
d700128c EZ |
1080 | @cindex @code{--nowindows} |
1081 | @cindex @code{-nw} | |
2df3850c | 1082 | ``No windows''. If @value{GDBN} comes with a graphical user interface |
96a2c332 | 1083 | (GUI) built in, then this option tells @value{GDBN} to only use the command-line |
2df3850c JM |
1084 | interface. If no GUI is available, this option has no effect. |
1085 | ||
1086 | @item -windows | |
1087 | @itemx -w | |
d700128c EZ |
1088 | @cindex @code{--windows} |
1089 | @cindex @code{-w} | |
2df3850c JM |
1090 | If @value{GDBN} includes a GUI, then this option requires it to be |
1091 | used if possible. | |
c906108c SS |
1092 | |
1093 | @item -cd @var{directory} | |
d700128c | 1094 | @cindex @code{--cd} |
c906108c SS |
1095 | Run @value{GDBN} using @var{directory} as its working directory, |
1096 | instead of the current directory. | |
1097 | ||
c906108c SS |
1098 | @item -fullname |
1099 | @itemx -f | |
d700128c EZ |
1100 | @cindex @code{--fullname} |
1101 | @cindex @code{-f} | |
7a292a7a SS |
1102 | @sc{gnu} Emacs sets this option when it runs @value{GDBN} as a |
1103 | subprocess. It tells @value{GDBN} to output the full file name and line | |
1104 | number in a standard, recognizable fashion each time a stack frame is | |
1105 | displayed (which includes each time your program stops). This | |
1106 | recognizable format looks like two @samp{\032} characters, followed by | |
1107 | the file name, line number and character position separated by colons, | |
1108 | and a newline. The Emacs-to-@value{GDBN} interface program uses the two | |
1109 | @samp{\032} characters as a signal to display the source code for the | |
1110 | frame. | |
c906108c | 1111 | |
d700128c EZ |
1112 | @item -epoch |
1113 | @cindex @code{--epoch} | |
1114 | The Epoch Emacs-@value{GDBN} interface sets this option when it runs | |
1115 | @value{GDBN} as a subprocess. It tells @value{GDBN} to modify its print | |
1116 | routines so as to allow Epoch to display values of expressions in a | |
1117 | separate window. | |
1118 | ||
1119 | @item -annotate @var{level} | |
1120 | @cindex @code{--annotate} | |
1121 | This option sets the @dfn{annotation level} inside @value{GDBN}. Its | |
1122 | effect is identical to using @samp{set annotate @var{level}} | |
086432e2 AC |
1123 | (@pxref{Annotations}). The annotation @var{level} controls how much |
1124 | information @value{GDBN} prints together with its prompt, values of | |
1125 | expressions, source lines, and other types of output. Level 0 is the | |
1126 | normal, level 1 is for use when @value{GDBN} is run as a subprocess of | |
1127 | @sc{gnu} Emacs, level 3 is the maximum annotation suitable for programs | |
1128 | that control @value{GDBN}, and level 2 has been deprecated. | |
1129 | ||
265eeb58 | 1130 | The annotation mechanism has largely been superseded by @sc{gdb/mi} |
086432e2 | 1131 | (@pxref{GDB/MI}). |
d700128c | 1132 | |
aa26fa3a TT |
1133 | @item --args |
1134 | @cindex @code{--args} | |
1135 | Change interpretation of command line so that arguments following the | |
1136 | executable file are passed as command line arguments to the inferior. | |
1137 | This option stops option processing. | |
1138 | ||
2df3850c JM |
1139 | @item -baud @var{bps} |
1140 | @itemx -b @var{bps} | |
d700128c EZ |
1141 | @cindex @code{--baud} |
1142 | @cindex @code{-b} | |
c906108c SS |
1143 | Set the line speed (baud rate or bits per second) of any serial |
1144 | interface used by @value{GDBN} for remote debugging. | |
c906108c | 1145 | |
f47b1503 AS |
1146 | @item -l @var{timeout} |
1147 | @cindex @code{-l} | |
1148 | Set the timeout (in seconds) of any communication used by @value{GDBN} | |
1149 | for remote debugging. | |
1150 | ||
c906108c | 1151 | @item -tty @var{device} |
d700128c EZ |
1152 | @itemx -t @var{device} |
1153 | @cindex @code{--tty} | |
1154 | @cindex @code{-t} | |
c906108c SS |
1155 | Run using @var{device} for your program's standard input and output. |
1156 | @c FIXME: kingdon thinks there is more to -tty. Investigate. | |
c906108c | 1157 | |
53a5351d | 1158 | @c resolve the situation of these eventually |
c4555f82 SC |
1159 | @item -tui |
1160 | @cindex @code{--tui} | |
d0d5df6f AC |
1161 | Activate the @dfn{Text User Interface} when starting. The Text User |
1162 | Interface manages several text windows on the terminal, showing | |
1163 | source, assembly, registers and @value{GDBN} command outputs | |
1164 | (@pxref{TUI, ,@value{GDBN} Text User Interface}). Alternatively, the | |
1165 | Text User Interface can be enabled by invoking the program | |
46ba6afa | 1166 | @samp{@value{GDBTUI}}. Do not use this option if you run @value{GDBN} from |
d0d5df6f | 1167 | Emacs (@pxref{Emacs, ,Using @value{GDBN} under @sc{gnu} Emacs}). |
53a5351d JM |
1168 | |
1169 | @c @item -xdb | |
d700128c | 1170 | @c @cindex @code{--xdb} |
53a5351d JM |
1171 | @c Run in XDB compatibility mode, allowing the use of certain XDB commands. |
1172 | @c For information, see the file @file{xdb_trans.html}, which is usually | |
1173 | @c installed in the directory @code{/opt/langtools/wdb/doc} on HP-UX | |
1174 | @c systems. | |
1175 | ||
d700128c EZ |
1176 | @item -interpreter @var{interp} |
1177 | @cindex @code{--interpreter} | |
1178 | Use the interpreter @var{interp} for interface with the controlling | |
1179 | program or device. This option is meant to be set by programs which | |
94bbb2c0 | 1180 | communicate with @value{GDBN} using it as a back end. |
21c294e6 | 1181 | @xref{Interpreters, , Command Interpreters}. |
94bbb2c0 | 1182 | |
da0f9dcd | 1183 | @samp{--interpreter=mi} (or @samp{--interpreter=mi2}) causes |
2fcf52f0 | 1184 | @value{GDBN} to use the @dfn{@sc{gdb/mi} interface} (@pxref{GDB/MI, , |
6b5e8c01 | 1185 | The @sc{gdb/mi} Interface}) included since @value{GDBN} version 6.0. The |
6c74ac8b AC |
1186 | previous @sc{gdb/mi} interface, included in @value{GDBN} version 5.3 and |
1187 | selected with @samp{--interpreter=mi1}, is deprecated. Earlier | |
1188 | @sc{gdb/mi} interfaces are no longer supported. | |
d700128c EZ |
1189 | |
1190 | @item -write | |
1191 | @cindex @code{--write} | |
1192 | Open the executable and core files for both reading and writing. This | |
1193 | is equivalent to the @samp{set write on} command inside @value{GDBN} | |
1194 | (@pxref{Patching}). | |
1195 | ||
1196 | @item -statistics | |
1197 | @cindex @code{--statistics} | |
1198 | This option causes @value{GDBN} to print statistics about time and | |
1199 | memory usage after it completes each command and returns to the prompt. | |
1200 | ||
1201 | @item -version | |
1202 | @cindex @code{--version} | |
1203 | This option causes @value{GDBN} to print its version number and | |
1204 | no-warranty blurb, and exit. | |
1205 | ||
c906108c SS |
1206 | @end table |
1207 | ||
6fc08d32 | 1208 | @node Startup |
79a6e687 | 1209 | @subsection What @value{GDBN} Does During Startup |
6fc08d32 EZ |
1210 | @cindex @value{GDBN} startup |
1211 | ||
1212 | Here's the description of what @value{GDBN} does during session startup: | |
1213 | ||
1214 | @enumerate | |
1215 | @item | |
1216 | Sets up the command interpreter as specified by the command line | |
1217 | (@pxref{Mode Options, interpreter}). | |
1218 | ||
1219 | @item | |
1220 | @cindex init file | |
098b41a6 JG |
1221 | Reads the system-wide @dfn{init file} (if @option{--with-system-gdbinit} was |
1222 | used when building @value{GDBN}; @pxref{System-wide configuration, | |
1223 | ,System-wide configuration and settings}) and executes all the commands in | |
1224 | that file. | |
1225 | ||
1226 | @item | |
1227 | Reads the init file (if any) in your home directory@footnote{On | |
6fc08d32 EZ |
1228 | DOS/Windows systems, the home directory is the one pointed to by the |
1229 | @code{HOME} environment variable.} and executes all the commands in | |
1230 | that file. | |
1231 | ||
1232 | @item | |
1233 | Processes command line options and operands. | |
1234 | ||
1235 | @item | |
1236 | Reads and executes the commands from init file (if any) in the current | |
119b882a EZ |
1237 | working directory. This is only done if the current directory is |
1238 | different from your home directory. Thus, you can have more than one | |
1239 | init file, one generic in your home directory, and another, specific | |
1240 | to the program you are debugging, in the directory where you invoke | |
6fc08d32 EZ |
1241 | @value{GDBN}. |
1242 | ||
1243 | @item | |
1244 | Reads command files specified by the @samp{-x} option. @xref{Command | |
1245 | Files}, for more details about @value{GDBN} command files. | |
1246 | ||
1247 | @item | |
1248 | Reads the command history recorded in the @dfn{history file}. | |
d620b259 | 1249 | @xref{Command History}, for more details about the command history and the |
6fc08d32 EZ |
1250 | files where @value{GDBN} records it. |
1251 | @end enumerate | |
1252 | ||
1253 | Init files use the same syntax as @dfn{command files} (@pxref{Command | |
1254 | Files}) and are processed by @value{GDBN} in the same way. The init | |
1255 | file in your home directory can set options (such as @samp{set | |
1256 | complaints}) that affect subsequent processing of command line options | |
1257 | and operands. Init files are not executed if you use the @samp{-nx} | |
79a6e687 | 1258 | option (@pxref{Mode Options, ,Choosing Modes}). |
6fc08d32 | 1259 | |
098b41a6 JG |
1260 | To display the list of init files loaded by gdb at startup, you |
1261 | can use @kbd{gdb --help}. | |
1262 | ||
6fc08d32 EZ |
1263 | @cindex init file name |
1264 | @cindex @file{.gdbinit} | |
119b882a | 1265 | @cindex @file{gdb.ini} |
8807d78b | 1266 | The @value{GDBN} init files are normally called @file{.gdbinit}. |
119b882a EZ |
1267 | The DJGPP port of @value{GDBN} uses the name @file{gdb.ini}, due to |
1268 | the limitations of file names imposed by DOS filesystems. The Windows | |
1269 | ports of @value{GDBN} use the standard name, but if they find a | |
1270 | @file{gdb.ini} file, they warn you about that and suggest to rename | |
1271 | the file to the standard name. | |
1272 | ||
6fc08d32 | 1273 | |
6d2ebf8b | 1274 | @node Quitting GDB |
c906108c SS |
1275 | @section Quitting @value{GDBN} |
1276 | @cindex exiting @value{GDBN} | |
1277 | @cindex leaving @value{GDBN} | |
1278 | ||
1279 | @table @code | |
1280 | @kindex quit @r{[}@var{expression}@r{]} | |
41afff9a | 1281 | @kindex q @r{(@code{quit})} |
96a2c332 SS |
1282 | @item quit @r{[}@var{expression}@r{]} |
1283 | @itemx q | |
1284 | To exit @value{GDBN}, use the @code{quit} command (abbreviated | |
c8aa23ab | 1285 | @code{q}), or type an end-of-file character (usually @kbd{Ctrl-d}). If you |
96a2c332 SS |
1286 | do not supply @var{expression}, @value{GDBN} will terminate normally; |
1287 | otherwise it will terminate using the result of @var{expression} as the | |
1288 | error code. | |
c906108c SS |
1289 | @end table |
1290 | ||
1291 | @cindex interrupt | |
c8aa23ab | 1292 | An interrupt (often @kbd{Ctrl-c}) does not exit from @value{GDBN}, but rather |
c906108c SS |
1293 | terminates the action of any @value{GDBN} command that is in progress and |
1294 | returns to @value{GDBN} command level. It is safe to type the interrupt | |
1295 | character at any time because @value{GDBN} does not allow it to take effect | |
1296 | until a time when it is safe. | |
1297 | ||
c906108c SS |
1298 | If you have been using @value{GDBN} to control an attached process or |
1299 | device, you can release it with the @code{detach} command | |
79a6e687 | 1300 | (@pxref{Attach, ,Debugging an Already-running Process}). |
c906108c | 1301 | |
6d2ebf8b | 1302 | @node Shell Commands |
79a6e687 | 1303 | @section Shell Commands |
c906108c SS |
1304 | |
1305 | If you need to execute occasional shell commands during your | |
1306 | debugging session, there is no need to leave or suspend @value{GDBN}; you can | |
1307 | just use the @code{shell} command. | |
1308 | ||
1309 | @table @code | |
1310 | @kindex shell | |
1311 | @cindex shell escape | |
1312 | @item shell @var{command string} | |
1313 | Invoke a standard shell to execute @var{command string}. | |
c906108c | 1314 | If it exists, the environment variable @code{SHELL} determines which |
d4f3574e SS |
1315 | shell to run. Otherwise @value{GDBN} uses the default shell |
1316 | (@file{/bin/sh} on Unix systems, @file{COMMAND.COM} on MS-DOS, etc.). | |
c906108c SS |
1317 | @end table |
1318 | ||
1319 | The utility @code{make} is often needed in development environments. | |
1320 | You do not have to use the @code{shell} command for this purpose in | |
1321 | @value{GDBN}: | |
1322 | ||
1323 | @table @code | |
1324 | @kindex make | |
1325 | @cindex calling make | |
1326 | @item make @var{make-args} | |
1327 | Execute the @code{make} program with the specified | |
1328 | arguments. This is equivalent to @samp{shell make @var{make-args}}. | |
1329 | @end table | |
1330 | ||
79a6e687 BW |
1331 | @node Logging Output |
1332 | @section Logging Output | |
0fac0b41 | 1333 | @cindex logging @value{GDBN} output |
9c16f35a | 1334 | @cindex save @value{GDBN} output to a file |
0fac0b41 DJ |
1335 | |
1336 | You may want to save the output of @value{GDBN} commands to a file. | |
1337 | There are several commands to control @value{GDBN}'s logging. | |
1338 | ||
1339 | @table @code | |
1340 | @kindex set logging | |
1341 | @item set logging on | |
1342 | Enable logging. | |
1343 | @item set logging off | |
1344 | Disable logging. | |
9c16f35a | 1345 | @cindex logging file name |
0fac0b41 DJ |
1346 | @item set logging file @var{file} |
1347 | Change the name of the current logfile. The default logfile is @file{gdb.txt}. | |
1348 | @item set logging overwrite [on|off] | |
1349 | By default, @value{GDBN} will append to the logfile. Set @code{overwrite} if | |
1350 | you want @code{set logging on} to overwrite the logfile instead. | |
1351 | @item set logging redirect [on|off] | |
1352 | By default, @value{GDBN} output will go to both the terminal and the logfile. | |
1353 | Set @code{redirect} if you want output to go only to the log file. | |
1354 | @kindex show logging | |
1355 | @item show logging | |
1356 | Show the current values of the logging settings. | |
1357 | @end table | |
1358 | ||
6d2ebf8b | 1359 | @node Commands |
c906108c SS |
1360 | @chapter @value{GDBN} Commands |
1361 | ||
1362 | You can abbreviate a @value{GDBN} command to the first few letters of the command | |
1363 | name, if that abbreviation is unambiguous; and you can repeat certain | |
1364 | @value{GDBN} commands by typing just @key{RET}. You can also use the @key{TAB} | |
1365 | key to get @value{GDBN} to fill out the rest of a word in a command (or to | |
1366 | show you the alternatives available, if there is more than one possibility). | |
1367 | ||
1368 | @menu | |
1369 | * Command Syntax:: How to give commands to @value{GDBN} | |
1370 | * Completion:: Command completion | |
1371 | * Help:: How to ask @value{GDBN} for help | |
1372 | @end menu | |
1373 | ||
6d2ebf8b | 1374 | @node Command Syntax |
79a6e687 | 1375 | @section Command Syntax |
c906108c SS |
1376 | |
1377 | A @value{GDBN} command is a single line of input. There is no limit on | |
1378 | how long it can be. It starts with a command name, which is followed by | |
1379 | arguments whose meaning depends on the command name. For example, the | |
1380 | command @code{step} accepts an argument which is the number of times to | |
1381 | step, as in @samp{step 5}. You can also use the @code{step} command | |
96a2c332 | 1382 | with no arguments. Some commands do not allow any arguments. |
c906108c SS |
1383 | |
1384 | @cindex abbreviation | |
1385 | @value{GDBN} command names may always be truncated if that abbreviation is | |
1386 | unambiguous. Other possible command abbreviations are listed in the | |
1387 | documentation for individual commands. In some cases, even ambiguous | |
1388 | abbreviations are allowed; for example, @code{s} is specially defined as | |
1389 | equivalent to @code{step} even though there are other commands whose | |
1390 | names start with @code{s}. You can test abbreviations by using them as | |
1391 | arguments to the @code{help} command. | |
1392 | ||
1393 | @cindex repeating commands | |
41afff9a | 1394 | @kindex RET @r{(repeat last command)} |
c906108c | 1395 | A blank line as input to @value{GDBN} (typing just @key{RET}) means to |
96a2c332 | 1396 | repeat the previous command. Certain commands (for example, @code{run}) |
c906108c SS |
1397 | will not repeat this way; these are commands whose unintentional |
1398 | repetition might cause trouble and which you are unlikely to want to | |
c45da7e6 EZ |
1399 | repeat. User-defined commands can disable this feature; see |
1400 | @ref{Define, dont-repeat}. | |
c906108c SS |
1401 | |
1402 | The @code{list} and @code{x} commands, when you repeat them with | |
1403 | @key{RET}, construct new arguments rather than repeating | |
1404 | exactly as typed. This permits easy scanning of source or memory. | |
1405 | ||
1406 | @value{GDBN} can also use @key{RET} in another way: to partition lengthy | |
1407 | output, in a way similar to the common utility @code{more} | |
79a6e687 | 1408 | (@pxref{Screen Size,,Screen Size}). Since it is easy to press one |
c906108c SS |
1409 | @key{RET} too many in this situation, @value{GDBN} disables command |
1410 | repetition after any command that generates this sort of display. | |
1411 | ||
41afff9a | 1412 | @kindex # @r{(a comment)} |
c906108c SS |
1413 | @cindex comment |
1414 | Any text from a @kbd{#} to the end of the line is a comment; it does | |
1415 | nothing. This is useful mainly in command files (@pxref{Command | |
79a6e687 | 1416 | Files,,Command Files}). |
c906108c | 1417 | |
88118b3a | 1418 | @cindex repeating command sequences |
c8aa23ab EZ |
1419 | @kindex Ctrl-o @r{(operate-and-get-next)} |
1420 | The @kbd{Ctrl-o} binding is useful for repeating a complex sequence of | |
7f9087cb | 1421 | commands. This command accepts the current line, like @key{RET}, and |
88118b3a TT |
1422 | then fetches the next line relative to the current line from the history |
1423 | for editing. | |
1424 | ||
6d2ebf8b | 1425 | @node Completion |
79a6e687 | 1426 | @section Command Completion |
c906108c SS |
1427 | |
1428 | @cindex completion | |
1429 | @cindex word completion | |
1430 | @value{GDBN} can fill in the rest of a word in a command for you, if there is | |
1431 | only one possibility; it can also show you what the valid possibilities | |
1432 | are for the next word in a command, at any time. This works for @value{GDBN} | |
1433 | commands, @value{GDBN} subcommands, and the names of symbols in your program. | |
1434 | ||
1435 | Press the @key{TAB} key whenever you want @value{GDBN} to fill out the rest | |
1436 | of a word. If there is only one possibility, @value{GDBN} fills in the | |
1437 | word, and waits for you to finish the command (or press @key{RET} to | |
1438 | enter it). For example, if you type | |
1439 | ||
1440 | @c FIXME "@key" does not distinguish its argument sufficiently to permit | |
1441 | @c complete accuracy in these examples; space introduced for clarity. | |
1442 | @c If texinfo enhancements make it unnecessary, it would be nice to | |
1443 | @c replace " @key" by "@key" in the following... | |
474c8240 | 1444 | @smallexample |
c906108c | 1445 | (@value{GDBP}) info bre @key{TAB} |
474c8240 | 1446 | @end smallexample |
c906108c SS |
1447 | |
1448 | @noindent | |
1449 | @value{GDBN} fills in the rest of the word @samp{breakpoints}, since that is | |
1450 | the only @code{info} subcommand beginning with @samp{bre}: | |
1451 | ||
474c8240 | 1452 | @smallexample |
c906108c | 1453 | (@value{GDBP}) info breakpoints |
474c8240 | 1454 | @end smallexample |
c906108c SS |
1455 | |
1456 | @noindent | |
1457 | You can either press @key{RET} at this point, to run the @code{info | |
1458 | breakpoints} command, or backspace and enter something else, if | |
1459 | @samp{breakpoints} does not look like the command you expected. (If you | |
1460 | were sure you wanted @code{info breakpoints} in the first place, you | |
1461 | might as well just type @key{RET} immediately after @samp{info bre}, | |
1462 | to exploit command abbreviations rather than command completion). | |
1463 | ||
1464 | If there is more than one possibility for the next word when you press | |
1465 | @key{TAB}, @value{GDBN} sounds a bell. You can either supply more | |
1466 | characters and try again, or just press @key{TAB} a second time; | |
1467 | @value{GDBN} displays all the possible completions for that word. For | |
1468 | example, you might want to set a breakpoint on a subroutine whose name | |
1469 | begins with @samp{make_}, but when you type @kbd{b make_@key{TAB}} @value{GDBN} | |
1470 | just sounds the bell. Typing @key{TAB} again displays all the | |
1471 | function names in your program that begin with those characters, for | |
1472 | example: | |
1473 | ||
474c8240 | 1474 | @smallexample |
c906108c SS |
1475 | (@value{GDBP}) b make_ @key{TAB} |
1476 | @exdent @value{GDBN} sounds bell; press @key{TAB} again, to see: | |
5d161b24 DB |
1477 | make_a_section_from_file make_environ |
1478 | make_abs_section make_function_type | |
1479 | make_blockvector make_pointer_type | |
1480 | make_cleanup make_reference_type | |
c906108c SS |
1481 | make_command make_symbol_completion_list |
1482 | (@value{GDBP}) b make_ | |
474c8240 | 1483 | @end smallexample |
c906108c SS |
1484 | |
1485 | @noindent | |
1486 | After displaying the available possibilities, @value{GDBN} copies your | |
1487 | partial input (@samp{b make_} in the example) so you can finish the | |
1488 | command. | |
1489 | ||
1490 | If you just want to see the list of alternatives in the first place, you | |
b37052ae | 1491 | can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?} |
7a292a7a | 1492 | means @kbd{@key{META} ?}. You can type this either by holding down a |
c906108c | 1493 | key designated as the @key{META} shift on your keyboard (if there is |
7a292a7a | 1494 | one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}. |
c906108c SS |
1495 | |
1496 | @cindex quotes in commands | |
1497 | @cindex completion of quoted strings | |
1498 | Sometimes the string you need, while logically a ``word'', may contain | |
7a292a7a SS |
1499 | parentheses or other characters that @value{GDBN} normally excludes from |
1500 | its notion of a word. To permit word completion to work in this | |
1501 | situation, you may enclose words in @code{'} (single quote marks) in | |
1502 | @value{GDBN} commands. | |
c906108c | 1503 | |
c906108c | 1504 | The most likely situation where you might need this is in typing the |
b37052ae EZ |
1505 | name of a C@t{++} function. This is because C@t{++} allows function |
1506 | overloading (multiple definitions of the same function, distinguished | |
1507 | by argument type). For example, when you want to set a breakpoint you | |
1508 | may need to distinguish whether you mean the version of @code{name} | |
1509 | that takes an @code{int} parameter, @code{name(int)}, or the version | |
1510 | that takes a @code{float} parameter, @code{name(float)}. To use the | |
1511 | word-completion facilities in this situation, type a single quote | |
1512 | @code{'} at the beginning of the function name. This alerts | |
1513 | @value{GDBN} that it may need to consider more information than usual | |
1514 | when you press @key{TAB} or @kbd{M-?} to request word completion: | |
c906108c | 1515 | |
474c8240 | 1516 | @smallexample |
96a2c332 | 1517 | (@value{GDBP}) b 'bubble( @kbd{M-?} |
c906108c SS |
1518 | bubble(double,double) bubble(int,int) |
1519 | (@value{GDBP}) b 'bubble( | |
474c8240 | 1520 | @end smallexample |
c906108c SS |
1521 | |
1522 | In some cases, @value{GDBN} can tell that completing a name requires using | |
1523 | quotes. When this happens, @value{GDBN} inserts the quote for you (while | |
1524 | completing as much as it can) if you do not type the quote in the first | |
1525 | place: | |
1526 | ||
474c8240 | 1527 | @smallexample |
c906108c SS |
1528 | (@value{GDBP}) b bub @key{TAB} |
1529 | @exdent @value{GDBN} alters your input line to the following, and rings a bell: | |
1530 | (@value{GDBP}) b 'bubble( | |
474c8240 | 1531 | @end smallexample |
c906108c SS |
1532 | |
1533 | @noindent | |
1534 | In general, @value{GDBN} can tell that a quote is needed (and inserts it) if | |
1535 | you have not yet started typing the argument list when you ask for | |
1536 | completion on an overloaded symbol. | |
1537 | ||
79a6e687 BW |
1538 | For more information about overloaded functions, see @ref{C Plus Plus |
1539 | Expressions, ,C@t{++} Expressions}. You can use the command @code{set | |
c906108c | 1540 | overload-resolution off} to disable overload resolution; |
79a6e687 | 1541 | see @ref{Debugging C Plus Plus, ,@value{GDBN} Features for C@t{++}}. |
c906108c | 1542 | |
65d12d83 TT |
1543 | @cindex completion of structure field names |
1544 | @cindex structure field name completion | |
1545 | @cindex completion of union field names | |
1546 | @cindex union field name completion | |
1547 | When completing in an expression which looks up a field in a | |
1548 | structure, @value{GDBN} also tries@footnote{The completer can be | |
1549 | confused by certain kinds of invalid expressions. Also, it only | |
1550 | examines the static type of the expression, not the dynamic type.} to | |
1551 | limit completions to the field names available in the type of the | |
1552 | left-hand-side: | |
1553 | ||
1554 | @smallexample | |
1555 | (@value{GDBP}) p gdb_stdout.@kbd{M-?} | |
1556 | magic to_delete to_fputs to_put to_rewind | |
1557 | to_data to_flush to_isatty to_read to_write | |
1558 | @end smallexample | |
1559 | ||
1560 | @noindent | |
1561 | This is because the @code{gdb_stdout} is a variable of the type | |
1562 | @code{struct ui_file} that is defined in @value{GDBN} sources as | |
1563 | follows: | |
1564 | ||
1565 | @smallexample | |
1566 | struct ui_file | |
1567 | @{ | |
1568 | int *magic; | |
1569 | ui_file_flush_ftype *to_flush; | |
1570 | ui_file_write_ftype *to_write; | |
1571 | ui_file_fputs_ftype *to_fputs; | |
1572 | ui_file_read_ftype *to_read; | |
1573 | ui_file_delete_ftype *to_delete; | |
1574 | ui_file_isatty_ftype *to_isatty; | |
1575 | ui_file_rewind_ftype *to_rewind; | |
1576 | ui_file_put_ftype *to_put; | |
1577 | void *to_data; | |
1578 | @} | |
1579 | @end smallexample | |
1580 | ||
c906108c | 1581 | |
6d2ebf8b | 1582 | @node Help |
79a6e687 | 1583 | @section Getting Help |
c906108c SS |
1584 | @cindex online documentation |
1585 | @kindex help | |
1586 | ||
5d161b24 | 1587 | You can always ask @value{GDBN} itself for information on its commands, |
c906108c SS |
1588 | using the command @code{help}. |
1589 | ||
1590 | @table @code | |
41afff9a | 1591 | @kindex h @r{(@code{help})} |
c906108c SS |
1592 | @item help |
1593 | @itemx h | |
1594 | You can use @code{help} (abbreviated @code{h}) with no arguments to | |
1595 | display a short list of named classes of commands: | |
1596 | ||
1597 | @smallexample | |
1598 | (@value{GDBP}) help | |
1599 | List of classes of commands: | |
1600 | ||
2df3850c | 1601 | aliases -- Aliases of other commands |
c906108c | 1602 | breakpoints -- Making program stop at certain points |
2df3850c | 1603 | data -- Examining data |
c906108c | 1604 | files -- Specifying and examining files |
2df3850c JM |
1605 | internals -- Maintenance commands |
1606 | obscure -- Obscure features | |
1607 | running -- Running the program | |
1608 | stack -- Examining the stack | |
c906108c SS |
1609 | status -- Status inquiries |
1610 | support -- Support facilities | |
12c27660 | 1611 | tracepoints -- Tracing of program execution without |
96a2c332 | 1612 | stopping the program |
c906108c | 1613 | user-defined -- User-defined commands |
c906108c | 1614 | |
5d161b24 | 1615 | Type "help" followed by a class name for a list of |
c906108c | 1616 | commands in that class. |
5d161b24 | 1617 | Type "help" followed by command name for full |
c906108c SS |
1618 | documentation. |
1619 | Command name abbreviations are allowed if unambiguous. | |
1620 | (@value{GDBP}) | |
1621 | @end smallexample | |
96a2c332 | 1622 | @c the above line break eliminates huge line overfull... |
c906108c SS |
1623 | |
1624 | @item help @var{class} | |
1625 | Using one of the general help classes as an argument, you can get a | |
1626 | list of the individual commands in that class. For example, here is the | |
1627 | help display for the class @code{status}: | |
1628 | ||
1629 | @smallexample | |
1630 | (@value{GDBP}) help status | |
1631 | Status inquiries. | |
1632 | ||
1633 | List of commands: | |
1634 | ||
1635 | @c Line break in "show" line falsifies real output, but needed | |
1636 | @c to fit in smallbook page size. | |
2df3850c | 1637 | info -- Generic command for showing things |
12c27660 | 1638 | about the program being debugged |
2df3850c | 1639 | show -- Generic command for showing things |
12c27660 | 1640 | about the debugger |
c906108c | 1641 | |
5d161b24 | 1642 | Type "help" followed by command name for full |
c906108c SS |
1643 | documentation. |
1644 | Command name abbreviations are allowed if unambiguous. | |
1645 | (@value{GDBP}) | |
1646 | @end smallexample | |
1647 | ||
1648 | @item help @var{command} | |
1649 | With a command name as @code{help} argument, @value{GDBN} displays a | |
1650 | short paragraph on how to use that command. | |
1651 | ||
6837a0a2 DB |
1652 | @kindex apropos |
1653 | @item apropos @var{args} | |
09d4efe1 | 1654 | The @code{apropos} command searches through all of the @value{GDBN} |
6837a0a2 | 1655 | commands, and their documentation, for the regular expression specified in |
99e008fe | 1656 | @var{args}. It prints out all matches found. For example: |
6837a0a2 DB |
1657 | |
1658 | @smallexample | |
1659 | apropos reload | |
1660 | @end smallexample | |
1661 | ||
b37052ae EZ |
1662 | @noindent |
1663 | results in: | |
6837a0a2 DB |
1664 | |
1665 | @smallexample | |
6d2ebf8b SS |
1666 | @c @group |
1667 | set symbol-reloading -- Set dynamic symbol table reloading | |
12c27660 | 1668 | multiple times in one run |
6d2ebf8b | 1669 | show symbol-reloading -- Show dynamic symbol table reloading |
12c27660 | 1670 | multiple times in one run |
6d2ebf8b | 1671 | @c @end group |
6837a0a2 DB |
1672 | @end smallexample |
1673 | ||
c906108c SS |
1674 | @kindex complete |
1675 | @item complete @var{args} | |
1676 | The @code{complete @var{args}} command lists all the possible completions | |
1677 | for the beginning of a command. Use @var{args} to specify the beginning of the | |
1678 | command you want completed. For example: | |
1679 | ||
1680 | @smallexample | |
1681 | complete i | |
1682 | @end smallexample | |
1683 | ||
1684 | @noindent results in: | |
1685 | ||
1686 | @smallexample | |
1687 | @group | |
2df3850c JM |
1688 | if |
1689 | ignore | |
c906108c SS |
1690 | info |
1691 | inspect | |
c906108c SS |
1692 | @end group |
1693 | @end smallexample | |
1694 | ||
1695 | @noindent This is intended for use by @sc{gnu} Emacs. | |
1696 | @end table | |
1697 | ||
1698 | In addition to @code{help}, you can use the @value{GDBN} commands @code{info} | |
1699 | and @code{show} to inquire about the state of your program, or the state | |
1700 | of @value{GDBN} itself. Each command supports many topics of inquiry; this | |
1701 | manual introduces each of them in the appropriate context. The listings | |
1702 | under @code{info} and under @code{show} in the Index point to | |
1703 | all the sub-commands. @xref{Index}. | |
1704 | ||
1705 | @c @group | |
1706 | @table @code | |
1707 | @kindex info | |
41afff9a | 1708 | @kindex i @r{(@code{info})} |
c906108c SS |
1709 | @item info |
1710 | This command (abbreviated @code{i}) is for describing the state of your | |
cda4ce5a | 1711 | program. For example, you can show the arguments passed to a function |
c906108c SS |
1712 | with @code{info args}, list the registers currently in use with @code{info |
1713 | registers}, or list the breakpoints you have set with @code{info breakpoints}. | |
1714 | You can get a complete list of the @code{info} sub-commands with | |
1715 | @w{@code{help info}}. | |
1716 | ||
1717 | @kindex set | |
1718 | @item set | |
5d161b24 | 1719 | You can assign the result of an expression to an environment variable with |
c906108c SS |
1720 | @code{set}. For example, you can set the @value{GDBN} prompt to a $-sign with |
1721 | @code{set prompt $}. | |
1722 | ||
1723 | @kindex show | |
1724 | @item show | |
5d161b24 | 1725 | In contrast to @code{info}, @code{show} is for describing the state of |
c906108c SS |
1726 | @value{GDBN} itself. |
1727 | You can change most of the things you can @code{show}, by using the | |
1728 | related command @code{set}; for example, you can control what number | |
1729 | system is used for displays with @code{set radix}, or simply inquire | |
1730 | which is currently in use with @code{show radix}. | |
1731 | ||
1732 | @kindex info set | |
1733 | To display all the settable parameters and their current | |
1734 | values, you can use @code{show} with no arguments; you may also use | |
1735 | @code{info set}. Both commands produce the same display. | |
1736 | @c FIXME: "info set" violates the rule that "info" is for state of | |
1737 | @c FIXME...program. Ck w/ GNU: "info set" to be called something else, | |
1738 | @c FIXME...or change desc of rule---eg "state of prog and debugging session"? | |
1739 | @end table | |
1740 | @c @end group | |
1741 | ||
1742 | Here are three miscellaneous @code{show} subcommands, all of which are | |
1743 | exceptional in lacking corresponding @code{set} commands: | |
1744 | ||
1745 | @table @code | |
1746 | @kindex show version | |
9c16f35a | 1747 | @cindex @value{GDBN} version number |
c906108c SS |
1748 | @item show version |
1749 | Show what version of @value{GDBN} is running. You should include this | |
2df3850c JM |
1750 | information in @value{GDBN} bug-reports. If multiple versions of |
1751 | @value{GDBN} are in use at your site, you may need to determine which | |
1752 | version of @value{GDBN} you are running; as @value{GDBN} evolves, new | |
1753 | commands are introduced, and old ones may wither away. Also, many | |
1754 | system vendors ship variant versions of @value{GDBN}, and there are | |
96a2c332 | 1755 | variant versions of @value{GDBN} in @sc{gnu}/Linux distributions as well. |
2df3850c JM |
1756 | The version number is the same as the one announced when you start |
1757 | @value{GDBN}. | |
c906108c SS |
1758 | |
1759 | @kindex show copying | |
09d4efe1 | 1760 | @kindex info copying |
9c16f35a | 1761 | @cindex display @value{GDBN} copyright |
c906108c | 1762 | @item show copying |
09d4efe1 | 1763 | @itemx info copying |
c906108c SS |
1764 | Display information about permission for copying @value{GDBN}. |
1765 | ||
1766 | @kindex show warranty | |
09d4efe1 | 1767 | @kindex info warranty |
c906108c | 1768 | @item show warranty |
09d4efe1 | 1769 | @itemx info warranty |
2df3850c | 1770 | Display the @sc{gnu} ``NO WARRANTY'' statement, or a warranty, |
96a2c332 | 1771 | if your version of @value{GDBN} comes with one. |
2df3850c | 1772 | |
c906108c SS |
1773 | @end table |
1774 | ||
6d2ebf8b | 1775 | @node Running |
c906108c SS |
1776 | @chapter Running Programs Under @value{GDBN} |
1777 | ||
1778 | When you run a program under @value{GDBN}, you must first generate | |
1779 | debugging information when you compile it. | |
7a292a7a SS |
1780 | |
1781 | You may start @value{GDBN} with its arguments, if any, in an environment | |
1782 | of your choice. If you are doing native debugging, you may redirect | |
1783 | your program's input and output, debug an already running process, or | |
1784 | kill a child process. | |
c906108c SS |
1785 | |
1786 | @menu | |
1787 | * Compilation:: Compiling for debugging | |
1788 | * Starting:: Starting your program | |
c906108c SS |
1789 | * Arguments:: Your program's arguments |
1790 | * Environment:: Your program's environment | |
c906108c SS |
1791 | |
1792 | * Working Directory:: Your program's working directory | |
1793 | * Input/Output:: Your program's input and output | |
1794 | * Attach:: Debugging an already-running process | |
1795 | * Kill Process:: Killing the child process | |
c906108c | 1796 | |
6c95b8df | 1797 | * Inferiors and Programs:: Debugging multiple inferiors and programs |
c906108c | 1798 | * Threads:: Debugging programs with multiple threads |
6c95b8df | 1799 | * Forks:: Debugging forks |
5c95884b | 1800 | * Checkpoint/Restart:: Setting a @emph{bookmark} to return to later |
c906108c SS |
1801 | @end menu |
1802 | ||
6d2ebf8b | 1803 | @node Compilation |
79a6e687 | 1804 | @section Compiling for Debugging |
c906108c SS |
1805 | |
1806 | In order to debug a program effectively, you need to generate | |
1807 | debugging information when you compile it. This debugging information | |
1808 | is stored in the object file; it describes the data type of each | |
1809 | variable or function and the correspondence between source line numbers | |
1810 | and addresses in the executable code. | |
1811 | ||
1812 | To request debugging information, specify the @samp{-g} option when you run | |
1813 | the compiler. | |
1814 | ||
514c4d71 | 1815 | Programs that are to be shipped to your customers are compiled with |
edb3359d | 1816 | optimizations, using the @samp{-O} compiler option. However, some |
514c4d71 EZ |
1817 | compilers are unable to handle the @samp{-g} and @samp{-O} options |
1818 | together. Using those compilers, you cannot generate optimized | |
c906108c SS |
1819 | executables containing debugging information. |
1820 | ||
514c4d71 | 1821 | @value{NGCC}, the @sc{gnu} C/C@t{++} compiler, supports @samp{-g} with or |
53a5351d JM |
1822 | without @samp{-O}, making it possible to debug optimized code. We |
1823 | recommend that you @emph{always} use @samp{-g} whenever you compile a | |
1824 | program. You may think your program is correct, but there is no sense | |
edb3359d | 1825 | in pushing your luck. For more information, see @ref{Optimized Code}. |
c906108c SS |
1826 | |
1827 | Older versions of the @sc{gnu} C compiler permitted a variant option | |
1828 | @w{@samp{-gg}} for debugging information. @value{GDBN} no longer supports this | |
1829 | format; if your @sc{gnu} C compiler has this option, do not use it. | |
1830 | ||
514c4d71 EZ |
1831 | @value{GDBN} knows about preprocessor macros and can show you their |
1832 | expansion (@pxref{Macros}). Most compilers do not include information | |
1833 | about preprocessor macros in the debugging information if you specify | |
1834 | the @option{-g} flag alone, because this information is rather large. | |
1835 | Version 3.1 and later of @value{NGCC}, the @sc{gnu} C compiler, | |
1836 | provides macro information if you specify the options | |
1837 | @option{-gdwarf-2} and @option{-g3}; the former option requests | |
1838 | debugging information in the Dwarf 2 format, and the latter requests | |
1839 | ``extra information''. In the future, we hope to find more compact | |
1840 | ways to represent macro information, so that it can be included with | |
1841 | @option{-g} alone. | |
1842 | ||
c906108c | 1843 | @need 2000 |
6d2ebf8b | 1844 | @node Starting |
79a6e687 | 1845 | @section Starting your Program |
c906108c SS |
1846 | @cindex starting |
1847 | @cindex running | |
1848 | ||
1849 | @table @code | |
1850 | @kindex run | |
41afff9a | 1851 | @kindex r @r{(@code{run})} |
c906108c SS |
1852 | @item run |
1853 | @itemx r | |
7a292a7a SS |
1854 | Use the @code{run} command to start your program under @value{GDBN}. |
1855 | You must first specify the program name (except on VxWorks) with an | |
1856 | argument to @value{GDBN} (@pxref{Invocation, ,Getting In and Out of | |
1857 | @value{GDBN}}), or by using the @code{file} or @code{exec-file} command | |
79a6e687 | 1858 | (@pxref{Files, ,Commands to Specify Files}). |
c906108c SS |
1859 | |
1860 | @end table | |
1861 | ||
c906108c SS |
1862 | If you are running your program in an execution environment that |
1863 | supports processes, @code{run} creates an inferior process and makes | |
8edfe269 DJ |
1864 | that process run your program. In some environments without processes, |
1865 | @code{run} jumps to the start of your program. Other targets, | |
1866 | like @samp{remote}, are always running. If you get an error | |
1867 | message like this one: | |
1868 | ||
1869 | @smallexample | |
1870 | The "remote" target does not support "run". | |
1871 | Try "help target" or "continue". | |
1872 | @end smallexample | |
1873 | ||
1874 | @noindent | |
1875 | then use @code{continue} to run your program. You may need @code{load} | |
1876 | first (@pxref{load}). | |
c906108c SS |
1877 | |
1878 | The execution of a program is affected by certain information it | |
1879 | receives from its superior. @value{GDBN} provides ways to specify this | |
1880 | information, which you must do @emph{before} starting your program. (You | |
1881 | can change it after starting your program, but such changes only affect | |
1882 | your program the next time you start it.) This information may be | |
1883 | divided into four categories: | |
1884 | ||
1885 | @table @asis | |
1886 | @item The @emph{arguments.} | |
1887 | Specify the arguments to give your program as the arguments of the | |
1888 | @code{run} command. If a shell is available on your target, the shell | |
1889 | is used to pass the arguments, so that you may use normal conventions | |
1890 | (such as wildcard expansion or variable substitution) in describing | |
1891 | the arguments. | |
1892 | In Unix systems, you can control which shell is used with the | |
1893 | @code{SHELL} environment variable. | |
79a6e687 | 1894 | @xref{Arguments, ,Your Program's Arguments}. |
c906108c SS |
1895 | |
1896 | @item The @emph{environment.} | |
1897 | Your program normally inherits its environment from @value{GDBN}, but you can | |
1898 | use the @value{GDBN} commands @code{set environment} and @code{unset | |
1899 | environment} to change parts of the environment that affect | |
79a6e687 | 1900 | your program. @xref{Environment, ,Your Program's Environment}. |
c906108c SS |
1901 | |
1902 | @item The @emph{working directory.} | |
1903 | Your program inherits its working directory from @value{GDBN}. You can set | |
1904 | the @value{GDBN} working directory with the @code{cd} command in @value{GDBN}. | |
79a6e687 | 1905 | @xref{Working Directory, ,Your Program's Working Directory}. |
c906108c SS |
1906 | |
1907 | @item The @emph{standard input and output.} | |
1908 | Your program normally uses the same device for standard input and | |
1909 | standard output as @value{GDBN} is using. You can redirect input and output | |
1910 | in the @code{run} command line, or you can use the @code{tty} command to | |
1911 | set a different device for your program. | |
79a6e687 | 1912 | @xref{Input/Output, ,Your Program's Input and Output}. |
c906108c SS |
1913 | |
1914 | @cindex pipes | |
1915 | @emph{Warning:} While input and output redirection work, you cannot use | |
1916 | pipes to pass the output of the program you are debugging to another | |
1917 | program; if you attempt this, @value{GDBN} is likely to wind up debugging the | |
1918 | wrong program. | |
1919 | @end table | |
c906108c SS |
1920 | |
1921 | When you issue the @code{run} command, your program begins to execute | |
79a6e687 | 1922 | immediately. @xref{Stopping, ,Stopping and Continuing}, for discussion |
c906108c SS |
1923 | of how to arrange for your program to stop. Once your program has |
1924 | stopped, you may call functions in your program, using the @code{print} | |
1925 | or @code{call} commands. @xref{Data, ,Examining Data}. | |
1926 | ||
1927 | If the modification time of your symbol file has changed since the last | |
1928 | time @value{GDBN} read its symbols, @value{GDBN} discards its symbol | |
1929 | table, and reads it again. When it does this, @value{GDBN} tries to retain | |
1930 | your current breakpoints. | |
1931 | ||
4e8b0763 JB |
1932 | @table @code |
1933 | @kindex start | |
1934 | @item start | |
1935 | @cindex run to main procedure | |
1936 | The name of the main procedure can vary from language to language. | |
1937 | With C or C@t{++}, the main procedure name is always @code{main}, but | |
1938 | other languages such as Ada do not require a specific name for their | |
1939 | main procedure. The debugger provides a convenient way to start the | |
1940 | execution of the program and to stop at the beginning of the main | |
1941 | procedure, depending on the language used. | |
1942 | ||
1943 | The @samp{start} command does the equivalent of setting a temporary | |
1944 | breakpoint at the beginning of the main procedure and then invoking | |
1945 | the @samp{run} command. | |
1946 | ||
f018e82f EZ |
1947 | @cindex elaboration phase |
1948 | Some programs contain an @dfn{elaboration} phase where some startup code is | |
1949 | executed before the main procedure is called. This depends on the | |
1950 | languages used to write your program. In C@t{++}, for instance, | |
4e8b0763 JB |
1951 | constructors for static and global objects are executed before |
1952 | @code{main} is called. It is therefore possible that the debugger stops | |
1953 | before reaching the main procedure. However, the temporary breakpoint | |
1954 | will remain to halt execution. | |
1955 | ||
1956 | Specify the arguments to give to your program as arguments to the | |
1957 | @samp{start} command. These arguments will be given verbatim to the | |
1958 | underlying @samp{run} command. Note that the same arguments will be | |
1959 | reused if no argument is provided during subsequent calls to | |
1960 | @samp{start} or @samp{run}. | |
1961 | ||
1962 | It is sometimes necessary to debug the program during elaboration. In | |
1963 | these cases, using the @code{start} command would stop the execution of | |
1964 | your program too late, as the program would have already completed the | |
1965 | elaboration phase. Under these circumstances, insert breakpoints in your | |
1966 | elaboration code before running your program. | |
ccd213ac DJ |
1967 | |
1968 | @kindex set exec-wrapper | |
1969 | @item set exec-wrapper @var{wrapper} | |
1970 | @itemx show exec-wrapper | |
1971 | @itemx unset exec-wrapper | |
1972 | When @samp{exec-wrapper} is set, the specified wrapper is used to | |
1973 | launch programs for debugging. @value{GDBN} starts your program | |
1974 | with a shell command of the form @kbd{exec @var{wrapper} | |
1975 | @var{program}}. Quoting is added to @var{program} and its | |
1976 | arguments, but not to @var{wrapper}, so you should add quotes if | |
1977 | appropriate for your shell. The wrapper runs until it executes | |
1978 | your program, and then @value{GDBN} takes control. | |
1979 | ||
1980 | You can use any program that eventually calls @code{execve} with | |
1981 | its arguments as a wrapper. Several standard Unix utilities do | |
1982 | this, e.g.@: @code{env} and @code{nohup}. Any Unix shell script ending | |
1983 | with @code{exec "$@@"} will also work. | |
1984 | ||
1985 | For example, you can use @code{env} to pass an environment variable to | |
1986 | the debugged program, without setting the variable in your shell's | |
1987 | environment: | |
1988 | ||
1989 | @smallexample | |
1990 | (@value{GDBP}) set exec-wrapper env 'LD_PRELOAD=libtest.so' | |
1991 | (@value{GDBP}) run | |
1992 | @end smallexample | |
1993 | ||
1994 | This command is available when debugging locally on most targets, excluding | |
1995 | @sc{djgpp}, Cygwin, MS Windows, and QNX Neutrino. | |
1996 | ||
10568435 JK |
1997 | @kindex set disable-randomization |
1998 | @item set disable-randomization | |
1999 | @itemx set disable-randomization on | |
2000 | This option (enabled by default in @value{GDBN}) will turn off the native | |
2001 | randomization of the virtual address space of the started program. This option | |
2002 | is useful for multiple debugging sessions to make the execution better | |
2003 | reproducible and memory addresses reusable across debugging sessions. | |
2004 | ||
2005 | This feature is implemented only on @sc{gnu}/Linux. You can get the same | |
2006 | behavior using | |
2007 | ||
2008 | @smallexample | |
2009 | (@value{GDBP}) set exec-wrapper setarch `uname -m` -R | |
2010 | @end smallexample | |
2011 | ||
2012 | @item set disable-randomization off | |
2013 | Leave the behavior of the started executable unchanged. Some bugs rear their | |
2014 | ugly heads only when the program is loaded at certain addresses. If your bug | |
2015 | disappears when you run the program under @value{GDBN}, that might be because | |
2016 | @value{GDBN} by default disables the address randomization on platforms, such | |
2017 | as @sc{gnu}/Linux, which do that for stand-alone programs. Use @kbd{set | |
2018 | disable-randomization off} to try to reproduce such elusive bugs. | |
2019 | ||
2020 | The virtual address space randomization is implemented only on @sc{gnu}/Linux. | |
2021 | It protects the programs against some kinds of security attacks. In these | |
2022 | cases the attacker needs to know the exact location of a concrete executable | |
2023 | code. Randomizing its location makes it impossible to inject jumps misusing | |
2024 | a code at its expected addresses. | |
2025 | ||
2026 | Prelinking shared libraries provides a startup performance advantage but it | |
2027 | makes addresses in these libraries predictable for privileged processes by | |
2028 | having just unprivileged access at the target system. Reading the shared | |
2029 | library binary gives enough information for assembling the malicious code | |
2030 | misusing it. Still even a prelinked shared library can get loaded at a new | |
2031 | random address just requiring the regular relocation process during the | |
2032 | startup. Shared libraries not already prelinked are always loaded at | |
2033 | a randomly chosen address. | |
2034 | ||
2035 | Position independent executables (PIE) contain position independent code | |
2036 | similar to the shared libraries and therefore such executables get loaded at | |
2037 | a randomly chosen address upon startup. PIE executables always load even | |
2038 | already prelinked shared libraries at a random address. You can build such | |
2039 | executable using @command{gcc -fPIE -pie}. | |
2040 | ||
2041 | Heap (malloc storage), stack and custom mmap areas are always placed randomly | |
2042 | (as long as the randomization is enabled). | |
2043 | ||
2044 | @item show disable-randomization | |
2045 | Show the current setting of the explicit disable of the native randomization of | |
2046 | the virtual address space of the started program. | |
2047 | ||
4e8b0763 JB |
2048 | @end table |
2049 | ||
6d2ebf8b | 2050 | @node Arguments |
79a6e687 | 2051 | @section Your Program's Arguments |
c906108c SS |
2052 | |
2053 | @cindex arguments (to your program) | |
2054 | The arguments to your program can be specified by the arguments of the | |
5d161b24 | 2055 | @code{run} command. |
c906108c SS |
2056 | They are passed to a shell, which expands wildcard characters and |
2057 | performs redirection of I/O, and thence to your program. Your | |
2058 | @code{SHELL} environment variable (if it exists) specifies what shell | |
2059 | @value{GDBN} uses. If you do not define @code{SHELL}, @value{GDBN} uses | |
d4f3574e SS |
2060 | the default shell (@file{/bin/sh} on Unix). |
2061 | ||
2062 | On non-Unix systems, the program is usually invoked directly by | |
2063 | @value{GDBN}, which emulates I/O redirection via the appropriate system | |
2064 | calls, and the wildcard characters are expanded by the startup code of | |
2065 | the program, not by the shell. | |
c906108c SS |
2066 | |
2067 | @code{run} with no arguments uses the same arguments used by the previous | |
2068 | @code{run}, or those set by the @code{set args} command. | |
2069 | ||
c906108c | 2070 | @table @code |
41afff9a | 2071 | @kindex set args |
c906108c SS |
2072 | @item set args |
2073 | Specify the arguments to be used the next time your program is run. If | |
2074 | @code{set args} has no arguments, @code{run} executes your program | |
2075 | with no arguments. Once you have run your program with arguments, | |
2076 | using @code{set args} before the next @code{run} is the only way to run | |
2077 | it again without arguments. | |
2078 | ||
2079 | @kindex show args | |
2080 | @item show args | |
2081 | Show the arguments to give your program when it is started. | |
2082 | @end table | |
2083 | ||
6d2ebf8b | 2084 | @node Environment |
79a6e687 | 2085 | @section Your Program's Environment |
c906108c SS |
2086 | |
2087 | @cindex environment (of your program) | |
2088 | The @dfn{environment} consists of a set of environment variables and | |
2089 | their values. Environment variables conventionally record such things as | |
2090 | your user name, your home directory, your terminal type, and your search | |
2091 | path for programs to run. Usually you set up environment variables with | |
2092 | the shell and they are inherited by all the other programs you run. When | |
2093 | debugging, it can be useful to try running your program with a modified | |
2094 | environment without having to start @value{GDBN} over again. | |
2095 | ||
2096 | @table @code | |
2097 | @kindex path | |
2098 | @item path @var{directory} | |
2099 | Add @var{directory} to the front of the @code{PATH} environment variable | |
17cc6a06 EZ |
2100 | (the search path for executables) that will be passed to your program. |
2101 | The value of @code{PATH} used by @value{GDBN} does not change. | |
d4f3574e SS |
2102 | You may specify several directory names, separated by whitespace or by a |
2103 | system-dependent separator character (@samp{:} on Unix, @samp{;} on | |
2104 | MS-DOS and MS-Windows). If @var{directory} is already in the path, it | |
2105 | is moved to the front, so it is searched sooner. | |
c906108c SS |
2106 | |
2107 | You can use the string @samp{$cwd} to refer to whatever is the current | |
2108 | working directory at the time @value{GDBN} searches the path. If you | |
2109 | use @samp{.} instead, it refers to the directory where you executed the | |
2110 | @code{path} command. @value{GDBN} replaces @samp{.} in the | |
2111 | @var{directory} argument (with the current path) before adding | |
2112 | @var{directory} to the search path. | |
2113 | @c 'path' is explicitly nonrepeatable, but RMS points out it is silly to | |
2114 | @c document that, since repeating it would be a no-op. | |
2115 | ||
2116 | @kindex show paths | |
2117 | @item show paths | |
2118 | Display the list of search paths for executables (the @code{PATH} | |
2119 | environment variable). | |
2120 | ||
2121 | @kindex show environment | |
2122 | @item show environment @r{[}@var{varname}@r{]} | |
2123 | Print the value of environment variable @var{varname} to be given to | |
2124 | your program when it starts. If you do not supply @var{varname}, | |
2125 | print the names and values of all environment variables to be given to | |
2126 | your program. You can abbreviate @code{environment} as @code{env}. | |
2127 | ||
2128 | @kindex set environment | |
53a5351d | 2129 | @item set environment @var{varname} @r{[}=@var{value}@r{]} |
c906108c SS |
2130 | Set environment variable @var{varname} to @var{value}. The value |
2131 | changes for your program only, not for @value{GDBN} itself. @var{value} may | |
2132 | be any string; the values of environment variables are just strings, and | |
2133 | any interpretation is supplied by your program itself. The @var{value} | |
2134 | parameter is optional; if it is eliminated, the variable is set to a | |
2135 | null value. | |
2136 | @c "any string" here does not include leading, trailing | |
2137 | @c blanks. Gnu asks: does anyone care? | |
2138 | ||
2139 | For example, this command: | |
2140 | ||
474c8240 | 2141 | @smallexample |
c906108c | 2142 | set env USER = foo |
474c8240 | 2143 | @end smallexample |
c906108c SS |
2144 | |
2145 | @noindent | |
d4f3574e | 2146 | tells the debugged program, when subsequently run, that its user is named |
c906108c SS |
2147 | @samp{foo}. (The spaces around @samp{=} are used for clarity here; they |
2148 | are not actually required.) | |
2149 | ||
2150 | @kindex unset environment | |
2151 | @item unset environment @var{varname} | |
2152 | Remove variable @var{varname} from the environment to be passed to your | |
2153 | program. This is different from @samp{set env @var{varname} =}; | |
2154 | @code{unset environment} removes the variable from the environment, | |
2155 | rather than assigning it an empty value. | |
2156 | @end table | |
2157 | ||
d4f3574e SS |
2158 | @emph{Warning:} On Unix systems, @value{GDBN} runs your program using |
2159 | the shell indicated | |
c906108c SS |
2160 | by your @code{SHELL} environment variable if it exists (or |
2161 | @code{/bin/sh} if not). If your @code{SHELL} variable names a shell | |
2162 | that runs an initialization file---such as @file{.cshrc} for C-shell, or | |
2163 | @file{.bashrc} for BASH---any variables you set in that file affect | |
2164 | your program. You may wish to move setting of environment variables to | |
2165 | files that are only run when you sign on, such as @file{.login} or | |
2166 | @file{.profile}. | |
2167 | ||
6d2ebf8b | 2168 | @node Working Directory |
79a6e687 | 2169 | @section Your Program's Working Directory |
c906108c SS |
2170 | |
2171 | @cindex working directory (of your program) | |
2172 | Each time you start your program with @code{run}, it inherits its | |
2173 | working directory from the current working directory of @value{GDBN}. | |
2174 | The @value{GDBN} working directory is initially whatever it inherited | |
2175 | from its parent process (typically the shell), but you can specify a new | |
2176 | working directory in @value{GDBN} with the @code{cd} command. | |
2177 | ||
2178 | The @value{GDBN} working directory also serves as a default for the commands | |
2179 | that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to | |
79a6e687 | 2180 | Specify Files}. |
c906108c SS |
2181 | |
2182 | @table @code | |
2183 | @kindex cd | |
721c2651 | 2184 | @cindex change working directory |
c906108c SS |
2185 | @item cd @var{directory} |
2186 | Set the @value{GDBN} working directory to @var{directory}. | |
2187 | ||
2188 | @kindex pwd | |
2189 | @item pwd | |
2190 | Print the @value{GDBN} working directory. | |
2191 | @end table | |
2192 | ||
60bf7e09 EZ |
2193 | It is generally impossible to find the current working directory of |
2194 | the process being debugged (since a program can change its directory | |
2195 | during its run). If you work on a system where @value{GDBN} is | |
2196 | configured with the @file{/proc} support, you can use the @code{info | |
2197 | proc} command (@pxref{SVR4 Process Information}) to find out the | |
2198 | current working directory of the debuggee. | |
2199 | ||
6d2ebf8b | 2200 | @node Input/Output |
79a6e687 | 2201 | @section Your Program's Input and Output |
c906108c SS |
2202 | |
2203 | @cindex redirection | |
2204 | @cindex i/o | |
2205 | @cindex terminal | |
2206 | By default, the program you run under @value{GDBN} does input and output to | |
5d161b24 | 2207 | the same terminal that @value{GDBN} uses. @value{GDBN} switches the terminal |
c906108c SS |
2208 | to its own terminal modes to interact with you, but it records the terminal |
2209 | modes your program was using and switches back to them when you continue | |
2210 | running your program. | |
2211 | ||
2212 | @table @code | |
2213 | @kindex info terminal | |
2214 | @item info terminal | |
2215 | Displays information recorded by @value{GDBN} about the terminal modes your | |
2216 | program is using. | |
2217 | @end table | |
2218 | ||
2219 | You can redirect your program's input and/or output using shell | |
2220 | redirection with the @code{run} command. For example, | |
2221 | ||
474c8240 | 2222 | @smallexample |
c906108c | 2223 | run > outfile |
474c8240 | 2224 | @end smallexample |
c906108c SS |
2225 | |
2226 | @noindent | |
2227 | starts your program, diverting its output to the file @file{outfile}. | |
2228 | ||
2229 | @kindex tty | |
2230 | @cindex controlling terminal | |
2231 | Another way to specify where your program should do input and output is | |
2232 | with the @code{tty} command. This command accepts a file name as | |
2233 | argument, and causes this file to be the default for future @code{run} | |
2234 | commands. It also resets the controlling terminal for the child | |
2235 | process, for future @code{run} commands. For example, | |
2236 | ||
474c8240 | 2237 | @smallexample |
c906108c | 2238 | tty /dev/ttyb |
474c8240 | 2239 | @end smallexample |
c906108c SS |
2240 | |
2241 | @noindent | |
2242 | directs that processes started with subsequent @code{run} commands | |
2243 | default to do input and output on the terminal @file{/dev/ttyb} and have | |
2244 | that as their controlling terminal. | |
2245 | ||
2246 | An explicit redirection in @code{run} overrides the @code{tty} command's | |
2247 | effect on the input/output device, but not its effect on the controlling | |
2248 | terminal. | |
2249 | ||
2250 | When you use the @code{tty} command or redirect input in the @code{run} | |
2251 | command, only the input @emph{for your program} is affected. The input | |
3cb3b8df BR |
2252 | for @value{GDBN} still comes from your terminal. @code{tty} is an alias |
2253 | for @code{set inferior-tty}. | |
2254 | ||
2255 | @cindex inferior tty | |
2256 | @cindex set inferior controlling terminal | |
2257 | You can use the @code{show inferior-tty} command to tell @value{GDBN} to | |
2258 | display the name of the terminal that will be used for future runs of your | |
2259 | program. | |
2260 | ||
2261 | @table @code | |
2262 | @item set inferior-tty /dev/ttyb | |
2263 | @kindex set inferior-tty | |
2264 | Set the tty for the program being debugged to /dev/ttyb. | |
2265 | ||
2266 | @item show inferior-tty | |
2267 | @kindex show inferior-tty | |
2268 | Show the current tty for the program being debugged. | |
2269 | @end table | |
c906108c | 2270 | |
6d2ebf8b | 2271 | @node Attach |
79a6e687 | 2272 | @section Debugging an Already-running Process |
c906108c SS |
2273 | @kindex attach |
2274 | @cindex attach | |
2275 | ||
2276 | @table @code | |
2277 | @item attach @var{process-id} | |
2278 | This command attaches to a running process---one that was started | |
2279 | outside @value{GDBN}. (@code{info files} shows your active | |
2280 | targets.) The command takes as argument a process ID. The usual way to | |
09d4efe1 | 2281 | find out the @var{process-id} of a Unix process is with the @code{ps} utility, |
c906108c SS |
2282 | or with the @samp{jobs -l} shell command. |
2283 | ||
2284 | @code{attach} does not repeat if you press @key{RET} a second time after | |
2285 | executing the command. | |
2286 | @end table | |
2287 | ||
2288 | To use @code{attach}, your program must be running in an environment | |
2289 | which supports processes; for example, @code{attach} does not work for | |
2290 | programs on bare-board targets that lack an operating system. You must | |
2291 | also have permission to send the process a signal. | |
2292 | ||
2293 | When you use @code{attach}, the debugger finds the program running in | |
2294 | the process first by looking in the current working directory, then (if | |
2295 | the program is not found) by using the source file search path | |
79a6e687 | 2296 | (@pxref{Source Path, ,Specifying Source Directories}). You can also use |
c906108c SS |
2297 | the @code{file} command to load the program. @xref{Files, ,Commands to |
2298 | Specify Files}. | |
2299 | ||
2300 | The first thing @value{GDBN} does after arranging to debug the specified | |
2301 | process is to stop it. You can examine and modify an attached process | |
53a5351d JM |
2302 | with all the @value{GDBN} commands that are ordinarily available when |
2303 | you start processes with @code{run}. You can insert breakpoints; you | |
2304 | can step and continue; you can modify storage. If you would rather the | |
2305 | process continue running, you may use the @code{continue} command after | |
c906108c SS |
2306 | attaching @value{GDBN} to the process. |
2307 | ||
2308 | @table @code | |
2309 | @kindex detach | |
2310 | @item detach | |
2311 | When you have finished debugging the attached process, you can use the | |
2312 | @code{detach} command to release it from @value{GDBN} control. Detaching | |
2313 | the process continues its execution. After the @code{detach} command, | |
2314 | that process and @value{GDBN} become completely independent once more, and you | |
2315 | are ready to @code{attach} another process or start one with @code{run}. | |
2316 | @code{detach} does not repeat if you press @key{RET} again after | |
2317 | executing the command. | |
2318 | @end table | |
2319 | ||
159fcc13 JK |
2320 | If you exit @value{GDBN} while you have an attached process, you detach |
2321 | that process. If you use the @code{run} command, you kill that process. | |
2322 | By default, @value{GDBN} asks for confirmation if you try to do either of these | |
2323 | things; you can control whether or not you need to confirm by using the | |
2324 | @code{set confirm} command (@pxref{Messages/Warnings, ,Optional Warnings and | |
79a6e687 | 2325 | Messages}). |
c906108c | 2326 | |
6d2ebf8b | 2327 | @node Kill Process |
79a6e687 | 2328 | @section Killing the Child Process |
c906108c SS |
2329 | |
2330 | @table @code | |
2331 | @kindex kill | |
2332 | @item kill | |
2333 | Kill the child process in which your program is running under @value{GDBN}. | |
2334 | @end table | |
2335 | ||
2336 | This command is useful if you wish to debug a core dump instead of a | |
2337 | running process. @value{GDBN} ignores any core dump file while your program | |
2338 | is running. | |
2339 | ||
2340 | On some operating systems, a program cannot be executed outside @value{GDBN} | |
2341 | while you have breakpoints set on it inside @value{GDBN}. You can use the | |
2342 | @code{kill} command in this situation to permit running your program | |
2343 | outside the debugger. | |
2344 | ||
2345 | The @code{kill} command is also useful if you wish to recompile and | |
2346 | relink your program, since on many systems it is impossible to modify an | |
2347 | executable file while it is running in a process. In this case, when you | |
2348 | next type @code{run}, @value{GDBN} notices that the file has changed, and | |
2349 | reads the symbol table again (while trying to preserve your current | |
2350 | breakpoint settings). | |
2351 | ||
6c95b8df PA |
2352 | @node Inferiors and Programs |
2353 | @section Debugging Multiple Inferiors and Programs | |
b77209e0 | 2354 | |
6c95b8df PA |
2355 | @value{GDBN} lets you run and debug multiple programs in a single |
2356 | session. In addition, @value{GDBN} on some systems may let you run | |
2357 | several programs simultaneously (otherwise you have to exit from one | |
2358 | before starting another). In the most general case, you can have | |
2359 | multiple threads of execution in each of multiple processes, launched | |
2360 | from multiple executables. | |
b77209e0 PA |
2361 | |
2362 | @cindex inferior | |
2363 | @value{GDBN} represents the state of each program execution with an | |
2364 | object called an @dfn{inferior}. An inferior typically corresponds to | |
2365 | a process, but is more general and applies also to targets that do not | |
2366 | have processes. Inferiors may be created before a process runs, and | |
6c95b8df PA |
2367 | may be retained after a process exits. Inferiors have unique |
2368 | identifiers that are different from process ids. Usually each | |
2369 | inferior will also have its own distinct address space, although some | |
2370 | embedded targets may have several inferiors running in different parts | |
2371 | of a single address space. Each inferior may in turn have multiple | |
2372 | threads running in it. | |
b77209e0 | 2373 | |
6c95b8df PA |
2374 | To find out what inferiors exist at any moment, use @w{@code{info |
2375 | inferiors}}: | |
b77209e0 PA |
2376 | |
2377 | @table @code | |
2378 | @kindex info inferiors | |
2379 | @item info inferiors | |
2380 | Print a list of all inferiors currently being managed by @value{GDBN}. | |
3a1ff0b6 PA |
2381 | |
2382 | @value{GDBN} displays for each inferior (in this order): | |
2383 | ||
2384 | @enumerate | |
2385 | @item | |
2386 | the inferior number assigned by @value{GDBN} | |
2387 | ||
2388 | @item | |
2389 | the target system's inferior identifier | |
6c95b8df PA |
2390 | |
2391 | @item | |
2392 | the name of the executable the inferior is running. | |
2393 | ||
3a1ff0b6 PA |
2394 | @end enumerate |
2395 | ||
2396 | @noindent | |
2397 | An asterisk @samp{*} preceding the @value{GDBN} inferior number | |
2398 | indicates the current inferior. | |
2399 | ||
2400 | For example, | |
2277426b | 2401 | @end table |
3a1ff0b6 PA |
2402 | @c end table here to get a little more width for example |
2403 | ||
2404 | @smallexample | |
2405 | (@value{GDBP}) info inferiors | |
6c95b8df PA |
2406 | Num Description Executable |
2407 | 2 process 2307 hello | |
2408 | * 1 process 3401 goodbye | |
3a1ff0b6 | 2409 | @end smallexample |
2277426b PA |
2410 | |
2411 | To switch focus between inferiors, use the @code{inferior} command: | |
2412 | ||
2413 | @table @code | |
3a1ff0b6 PA |
2414 | @kindex inferior @var{infno} |
2415 | @item inferior @var{infno} | |
2416 | Make inferior number @var{infno} the current inferior. The argument | |
2417 | @var{infno} is the inferior number assigned by @value{GDBN}, as shown | |
2418 | in the first field of the @samp{info inferiors} display. | |
2277426b PA |
2419 | @end table |
2420 | ||
6c95b8df PA |
2421 | |
2422 | You can get multiple executables into a debugging session via the | |
2423 | @code{add-inferior} and @w{@code{clone-inferior}} commands. On some | |
2424 | systems @value{GDBN} can add inferiors to the debug session | |
2425 | automatically by following calls to @code{fork} and @code{exec}. To | |
2426 | remove inferiors from the debugging session use the | |
2427 | @w{@code{remove-inferior}} command. | |
2428 | ||
2429 | @table @code | |
2430 | @kindex add-inferior | |
2431 | @item add-inferior [ -copies @var{n} ] [ -exec @var{executable} ] | |
2432 | Adds @var{n} inferiors to be run using @var{executable} as the | |
2433 | executable. @var{n} defaults to 1. If no executable is specified, | |
2434 | the inferiors begins empty, with no program. You can still assign or | |
2435 | change the program assigned to the inferior at any time by using the | |
2436 | @code{file} command with the executable name as its argument. | |
2437 | ||
2438 | @kindex clone-inferior | |
2439 | @item clone-inferior [ -copies @var{n} ] [ @var{infno} ] | |
2440 | Adds @var{n} inferiors ready to execute the same program as inferior | |
2441 | @var{infno}. @var{n} defaults to 1. @var{infno} defaults to the | |
2442 | number of the current inferior. This is a convenient command when you | |
2443 | want to run another instance of the inferior you are debugging. | |
2444 | ||
2445 | @smallexample | |
2446 | (@value{GDBP}) info inferiors | |
2447 | Num Description Executable | |
2448 | * 1 process 29964 helloworld | |
2449 | (@value{GDBP}) clone-inferior | |
2450 | Added inferior 2. | |
2451 | 1 inferiors added. | |
2452 | (@value{GDBP}) info inferiors | |
2453 | Num Description Executable | |
2454 | 2 <null> helloworld | |
2455 | * 1 process 29964 helloworld | |
2456 | @end smallexample | |
2457 | ||
2458 | You can now simply switch focus to inferior 2 and run it. | |
2459 | ||
2460 | @kindex remove-inferior | |
2461 | @item remove-inferior @var{infno} | |
2462 | Removes the inferior @var{infno}. It is not possible to remove an | |
2463 | inferior that is running with this command. For those, use the | |
2464 | @code{kill} or @code{detach} command first. | |
2465 | ||
2466 | @end table | |
2467 | ||
2468 | To quit debugging one of the running inferiors that is not the current | |
2469 | inferior, you can either detach from it by using the @w{@code{detach | |
2470 | inferior}} command (allowing it to run independently), or kill it | |
2471 | using the @w{@code{kill inferior}} command: | |
2277426b PA |
2472 | |
2473 | @table @code | |
3a1ff0b6 PA |
2474 | @kindex detach inferior @var{infno} |
2475 | @item detach inferior @var{infno} | |
2277426b | 2476 | Detach from the inferior identified by @value{GDBN} inferior number |
3a1ff0b6 | 2477 | @var{infno}, and remove it from the inferior list. |
2277426b | 2478 | |
3a1ff0b6 PA |
2479 | @kindex kill inferior @var{infno} |
2480 | @item kill inferior @var{infno} | |
2277426b | 2481 | Kill the inferior identified by @value{GDBN} inferior number |
3a1ff0b6 | 2482 | @var{infno}, and remove it from the inferior list. |
2277426b PA |
2483 | @end table |
2484 | ||
6c95b8df PA |
2485 | After the successful completion of a command such as @code{detach}, |
2486 | @code{detach inferior}, @code{kill} or @code{kill inferior}, or after | |
2487 | a normal process exit, the inferior is still valid and listed with | |
2488 | @code{info inferiors}, ready to be restarted. | |
2489 | ||
2490 | ||
2277426b PA |
2491 | To be notified when inferiors are started or exit under @value{GDBN}'s |
2492 | control use @w{@code{set print inferior-events}}: | |
b77209e0 | 2493 | |
2277426b | 2494 | @table @code |
b77209e0 PA |
2495 | @kindex set print inferior-events |
2496 | @cindex print messages on inferior start and exit | |
2497 | @item set print inferior-events | |
2498 | @itemx set print inferior-events on | |
2499 | @itemx set print inferior-events off | |
2500 | The @code{set print inferior-events} command allows you to enable or | |
2501 | disable printing of messages when @value{GDBN} notices that new | |
2502 | inferiors have started or that inferiors have exited or have been | |
2503 | detached. By default, these messages will not be printed. | |
2504 | ||
2505 | @kindex show print inferior-events | |
2506 | @item show print inferior-events | |
2507 | Show whether messages will be printed when @value{GDBN} detects that | |
2508 | inferiors have started, exited or have been detached. | |
2509 | @end table | |
2510 | ||
6c95b8df PA |
2511 | Many commands will work the same with multiple programs as with a |
2512 | single program: e.g., @code{print myglobal} will simply display the | |
2513 | value of @code{myglobal} in the current inferior. | |
2514 | ||
2515 | ||
2516 | Occasionaly, when debugging @value{GDBN} itself, it may be useful to | |
2517 | get more info about the relationship of inferiors, programs, address | |
2518 | spaces in a debug session. You can do that with the @w{@code{maint | |
2519 | info program-spaces}} command. | |
2520 | ||
2521 | @table @code | |
2522 | @kindex maint info program-spaces | |
2523 | @item maint info program-spaces | |
2524 | Print a list of all program spaces currently being managed by | |
2525 | @value{GDBN}. | |
2526 | ||
2527 | @value{GDBN} displays for each program space (in this order): | |
2528 | ||
2529 | @enumerate | |
2530 | @item | |
2531 | the program space number assigned by @value{GDBN} | |
2532 | ||
2533 | @item | |
2534 | the name of the executable loaded into the program space, with e.g., | |
2535 | the @code{file} command. | |
2536 | ||
2537 | @end enumerate | |
2538 | ||
2539 | @noindent | |
2540 | An asterisk @samp{*} preceding the @value{GDBN} program space number | |
2541 | indicates the current program space. | |
2542 | ||
2543 | In addition, below each program space line, @value{GDBN} prints extra | |
2544 | information that isn't suitable to display in tabular form. For | |
2545 | example, the list of inferiors bound to the program space. | |
2546 | ||
2547 | @smallexample | |
2548 | (@value{GDBP}) maint info program-spaces | |
2549 | Id Executable | |
2550 | 2 goodbye | |
2551 | Bound inferiors: ID 1 (process 21561) | |
2552 | * 1 hello | |
2553 | @end smallexample | |
2554 | ||
2555 | Here we can see that no inferior is running the program @code{hello}, | |
2556 | while @code{process 21561} is running the program @code{goodbye}. On | |
2557 | some targets, it is possible that multiple inferiors are bound to the | |
2558 | same program space. The most common example is that of debugging both | |
2559 | the parent and child processes of a @code{vfork} call. For example, | |
2560 | ||
2561 | @smallexample | |
2562 | (@value{GDBP}) maint info program-spaces | |
2563 | Id Executable | |
2564 | * 1 vfork-test | |
2565 | Bound inferiors: ID 2 (process 18050), ID 1 (process 18045) | |
2566 | @end smallexample | |
2567 | ||
2568 | Here, both inferior 2 and inferior 1 are running in the same program | |
2569 | space as a result of inferior 1 having executed a @code{vfork} call. | |
2570 | @end table | |
2571 | ||
6d2ebf8b | 2572 | @node Threads |
79a6e687 | 2573 | @section Debugging Programs with Multiple Threads |
c906108c SS |
2574 | |
2575 | @cindex threads of execution | |
2576 | @cindex multiple threads | |
2577 | @cindex switching threads | |
2578 | In some operating systems, such as HP-UX and Solaris, a single program | |
2579 | may have more than one @dfn{thread} of execution. The precise semantics | |
2580 | of threads differ from one operating system to another, but in general | |
2581 | the threads of a single program are akin to multiple processes---except | |
2582 | that they share one address space (that is, they can all examine and | |
2583 | modify the same variables). On the other hand, each thread has its own | |
2584 | registers and execution stack, and perhaps private memory. | |
2585 | ||
2586 | @value{GDBN} provides these facilities for debugging multi-thread | |
2587 | programs: | |
2588 | ||
2589 | @itemize @bullet | |
2590 | @item automatic notification of new threads | |
2591 | @item @samp{thread @var{threadno}}, a command to switch among threads | |
2592 | @item @samp{info threads}, a command to inquire about existing threads | |
5d161b24 | 2593 | @item @samp{thread apply [@var{threadno}] [@var{all}] @var{args}}, |
c906108c SS |
2594 | a command to apply a command to a list of threads |
2595 | @item thread-specific breakpoints | |
93815fbf VP |
2596 | @item @samp{set print thread-events}, which controls printing of |
2597 | messages on thread start and exit. | |
17a37d48 PP |
2598 | @item @samp{set libthread-db-search-path @var{path}}, which lets |
2599 | the user specify which @code{libthread_db} to use if the default choice | |
2600 | isn't compatible with the program. | |
c906108c SS |
2601 | @end itemize |
2602 | ||
c906108c SS |
2603 | @quotation |
2604 | @emph{Warning:} These facilities are not yet available on every | |
2605 | @value{GDBN} configuration where the operating system supports threads. | |
2606 | If your @value{GDBN} does not support threads, these commands have no | |
2607 | effect. For example, a system without thread support shows no output | |
2608 | from @samp{info threads}, and always rejects the @code{thread} command, | |
2609 | like this: | |
2610 | ||
2611 | @smallexample | |
2612 | (@value{GDBP}) info threads | |
2613 | (@value{GDBP}) thread 1 | |
2614 | Thread ID 1 not known. Use the "info threads" command to | |
2615 | see the IDs of currently known threads. | |
2616 | @end smallexample | |
2617 | @c FIXME to implementors: how hard would it be to say "sorry, this GDB | |
2618 | @c doesn't support threads"? | |
2619 | @end quotation | |
c906108c SS |
2620 | |
2621 | @cindex focus of debugging | |
2622 | @cindex current thread | |
2623 | The @value{GDBN} thread debugging facility allows you to observe all | |
2624 | threads while your program runs---but whenever @value{GDBN} takes | |
2625 | control, one thread in particular is always the focus of debugging. | |
2626 | This thread is called the @dfn{current thread}. Debugging commands show | |
2627 | program information from the perspective of the current thread. | |
2628 | ||
41afff9a | 2629 | @cindex @code{New} @var{systag} message |
c906108c SS |
2630 | @cindex thread identifier (system) |
2631 | @c FIXME-implementors!! It would be more helpful if the [New...] message | |
2632 | @c included GDB's numeric thread handle, so you could just go to that | |
2633 | @c thread without first checking `info threads'. | |
2634 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2635 | the target system's identification for the thread with a message in the | |
2636 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2637 | whose form varies depending on the particular system. For example, on | |
8807d78b | 2638 | @sc{gnu}/Linux, you might see |
c906108c | 2639 | |
474c8240 | 2640 | @smallexample |
8807d78b | 2641 | [New Thread 46912507313328 (LWP 25582)] |
474c8240 | 2642 | @end smallexample |
c906108c SS |
2643 | |
2644 | @noindent | |
2645 | when @value{GDBN} notices a new thread. In contrast, on an SGI system, | |
2646 | the @var{systag} is simply something like @samp{process 368}, with no | |
2647 | further qualifier. | |
2648 | ||
2649 | @c FIXME!! (1) Does the [New...] message appear even for the very first | |
2650 | @c thread of a program, or does it only appear for the | |
6ca652b0 | 2651 | @c second---i.e.@: when it becomes obvious we have a multithread |
c906108c SS |
2652 | @c program? |
2653 | @c (2) *Is* there necessarily a first thread always? Or do some | |
2654 | @c multithread systems permit starting a program with multiple | |
5d161b24 | 2655 | @c threads ab initio? |
c906108c SS |
2656 | |
2657 | @cindex thread number | |
2658 | @cindex thread identifier (GDB) | |
2659 | For debugging purposes, @value{GDBN} associates its own thread | |
2660 | number---always a single integer---with each thread in your program. | |
2661 | ||
2662 | @table @code | |
2663 | @kindex info threads | |
2664 | @item info threads | |
2665 | Display a summary of all threads currently in your | |
2666 | program. @value{GDBN} displays for each thread (in this order): | |
2667 | ||
2668 | @enumerate | |
09d4efe1 EZ |
2669 | @item |
2670 | the thread number assigned by @value{GDBN} | |
c906108c | 2671 | |
09d4efe1 EZ |
2672 | @item |
2673 | the target system's thread identifier (@var{systag}) | |
c906108c | 2674 | |
09d4efe1 EZ |
2675 | @item |
2676 | the current stack frame summary for that thread | |
c906108c SS |
2677 | @end enumerate |
2678 | ||
2679 | @noindent | |
2680 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2681 | indicates the current thread. | |
2682 | ||
5d161b24 | 2683 | For example, |
c906108c SS |
2684 | @end table |
2685 | @c end table here to get a little more width for example | |
2686 | ||
2687 | @smallexample | |
2688 | (@value{GDBP}) info threads | |
2689 | 3 process 35 thread 27 0x34e5 in sigpause () | |
2690 | 2 process 35 thread 23 0x34e5 in sigpause () | |
2691 | * 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8) | |
2692 | at threadtest.c:68 | |
2693 | @end smallexample | |
53a5351d JM |
2694 | |
2695 | On HP-UX systems: | |
c906108c | 2696 | |
4644b6e3 EZ |
2697 | @cindex debugging multithreaded programs (on HP-UX) |
2698 | @cindex thread identifier (GDB), on HP-UX | |
c906108c SS |
2699 | For debugging purposes, @value{GDBN} associates its own thread |
2700 | number---a small integer assigned in thread-creation order---with each | |
2701 | thread in your program. | |
2702 | ||
41afff9a EZ |
2703 | @cindex @code{New} @var{systag} message, on HP-UX |
2704 | @cindex thread identifier (system), on HP-UX | |
c906108c SS |
2705 | @c FIXME-implementors!! It would be more helpful if the [New...] message |
2706 | @c included GDB's numeric thread handle, so you could just go to that | |
2707 | @c thread without first checking `info threads'. | |
2708 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2709 | both @value{GDBN}'s thread number and the target system's identification for the thread with a message in the | |
2710 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2711 | whose form varies depending on the particular system. For example, on | |
2712 | HP-UX, you see | |
2713 | ||
474c8240 | 2714 | @smallexample |
c906108c | 2715 | [New thread 2 (system thread 26594)] |
474c8240 | 2716 | @end smallexample |
c906108c SS |
2717 | |
2718 | @noindent | |
5d161b24 | 2719 | when @value{GDBN} notices a new thread. |
c906108c SS |
2720 | |
2721 | @table @code | |
4644b6e3 | 2722 | @kindex info threads (HP-UX) |
c906108c SS |
2723 | @item info threads |
2724 | Display a summary of all threads currently in your | |
2725 | program. @value{GDBN} displays for each thread (in this order): | |
2726 | ||
2727 | @enumerate | |
2728 | @item the thread number assigned by @value{GDBN} | |
2729 | ||
2730 | @item the target system's thread identifier (@var{systag}) | |
2731 | ||
2732 | @item the current stack frame summary for that thread | |
2733 | @end enumerate | |
2734 | ||
2735 | @noindent | |
2736 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2737 | indicates the current thread. | |
2738 | ||
5d161b24 | 2739 | For example, |
c906108c SS |
2740 | @end table |
2741 | @c end table here to get a little more width for example | |
2742 | ||
474c8240 | 2743 | @smallexample |
c906108c | 2744 | (@value{GDBP}) info threads |
6d2ebf8b SS |
2745 | * 3 system thread 26607 worker (wptr=0x7b09c318 "@@") \@* |
2746 | at quicksort.c:137 | |
2747 | 2 system thread 26606 0x7b0030d8 in __ksleep () \@* | |
2748 | from /usr/lib/libc.2 | |
2749 | 1 system thread 27905 0x7b003498 in _brk () \@* | |
2750 | from /usr/lib/libc.2 | |
474c8240 | 2751 | @end smallexample |
c906108c | 2752 | |
c45da7e6 EZ |
2753 | On Solaris, you can display more information about user threads with a |
2754 | Solaris-specific command: | |
2755 | ||
2756 | @table @code | |
2757 | @item maint info sol-threads | |
2758 | @kindex maint info sol-threads | |
2759 | @cindex thread info (Solaris) | |
2760 | Display info on Solaris user threads. | |
2761 | @end table | |
2762 | ||
c906108c SS |
2763 | @table @code |
2764 | @kindex thread @var{threadno} | |
2765 | @item thread @var{threadno} | |
2766 | Make thread number @var{threadno} the current thread. The command | |
2767 | argument @var{threadno} is the internal @value{GDBN} thread number, as | |
2768 | shown in the first field of the @samp{info threads} display. | |
2769 | @value{GDBN} responds by displaying the system identifier of the thread | |
2770 | you selected, and its current stack frame summary: | |
2771 | ||
2772 | @smallexample | |
2773 | @c FIXME!! This example made up; find a @value{GDBN} w/threads and get real one | |
2774 | (@value{GDBP}) thread 2 | |
c906108c | 2775 | [Switching to process 35 thread 23] |
c906108c SS |
2776 | 0x34e5 in sigpause () |
2777 | @end smallexample | |
2778 | ||
2779 | @noindent | |
2780 | As with the @samp{[New @dots{}]} message, the form of the text after | |
2781 | @samp{Switching to} depends on your system's conventions for identifying | |
5d161b24 | 2782 | threads. |
c906108c | 2783 | |
9c16f35a | 2784 | @kindex thread apply |
638ac427 | 2785 | @cindex apply command to several threads |
839c27b7 EZ |
2786 | @item thread apply [@var{threadno}] [@var{all}] @var{command} |
2787 | The @code{thread apply} command allows you to apply the named | |
2788 | @var{command} to one or more threads. Specify the numbers of the | |
2789 | threads that you want affected with the command argument | |
2790 | @var{threadno}. It can be a single thread number, one of the numbers | |
2791 | shown in the first field of the @samp{info threads} display; or it | |
2792 | could be a range of thread numbers, as in @code{2-4}. To apply a | |
2793 | command to all threads, type @kbd{thread apply all @var{command}}. | |
93815fbf VP |
2794 | |
2795 | @kindex set print thread-events | |
2796 | @cindex print messages on thread start and exit | |
2797 | @item set print thread-events | |
2798 | @itemx set print thread-events on | |
2799 | @itemx set print thread-events off | |
2800 | The @code{set print thread-events} command allows you to enable or | |
2801 | disable printing of messages when @value{GDBN} notices that new threads have | |
2802 | started or that threads have exited. By default, these messages will | |
2803 | be printed if detection of these events is supported by the target. | |
2804 | Note that these messages cannot be disabled on all targets. | |
2805 | ||
2806 | @kindex show print thread-events | |
2807 | @item show print thread-events | |
2808 | Show whether messages will be printed when @value{GDBN} detects that threads | |
2809 | have started and exited. | |
c906108c SS |
2810 | @end table |
2811 | ||
79a6e687 | 2812 | @xref{Thread Stops,,Stopping and Starting Multi-thread Programs}, for |
c906108c SS |
2813 | more information about how @value{GDBN} behaves when you stop and start |
2814 | programs with multiple threads. | |
2815 | ||
79a6e687 | 2816 | @xref{Set Watchpoints,,Setting Watchpoints}, for information about |
c906108c | 2817 | watchpoints in programs with multiple threads. |
c906108c | 2818 | |
17a37d48 PP |
2819 | @table @code |
2820 | @kindex set libthread-db-search-path | |
2821 | @cindex search path for @code{libthread_db} | |
2822 | @item set libthread-db-search-path @r{[}@var{path}@r{]} | |
2823 | If this variable is set, @var{path} is a colon-separated list of | |
2824 | directories @value{GDBN} will use to search for @code{libthread_db}. | |
2825 | If you omit @var{path}, @samp{libthread-db-search-path} will be reset to | |
2826 | an empty list. | |
2827 | ||
2828 | On @sc{gnu}/Linux and Solaris systems, @value{GDBN} uses a ``helper'' | |
2829 | @code{libthread_db} library to obtain information about threads in the | |
2830 | inferior process. @value{GDBN} will use @samp{libthread-db-search-path} | |
2831 | to find @code{libthread_db}. If that fails, @value{GDBN} will continue | |
2832 | with default system shared library directories, and finally the directory | |
2833 | from which @code{libpthread} was loaded in the inferior process. | |
2834 | ||
2835 | For any @code{libthread_db} library @value{GDBN} finds in above directories, | |
2836 | @value{GDBN} attempts to initialize it with the current inferior process. | |
2837 | If this initialization fails (which could happen because of a version | |
2838 | mismatch between @code{libthread_db} and @code{libpthread}), @value{GDBN} | |
2839 | will unload @code{libthread_db}, and continue with the next directory. | |
2840 | If none of @code{libthread_db} libraries initialize successfully, | |
2841 | @value{GDBN} will issue a warning and thread debugging will be disabled. | |
2842 | ||
2843 | Setting @code{libthread-db-search-path} is currently implemented | |
2844 | only on some platforms. | |
2845 | ||
2846 | @kindex show libthread-db-search-path | |
2847 | @item show libthread-db-search-path | |
2848 | Display current libthread_db search path. | |
2849 | @end table | |
2850 | ||
6c95b8df PA |
2851 | @node Forks |
2852 | @section Debugging Forks | |
c906108c SS |
2853 | |
2854 | @cindex fork, debugging programs which call | |
2855 | @cindex multiple processes | |
2856 | @cindex processes, multiple | |
53a5351d JM |
2857 | On most systems, @value{GDBN} has no special support for debugging |
2858 | programs which create additional processes using the @code{fork} | |
2859 | function. When a program forks, @value{GDBN} will continue to debug the | |
2860 | parent process and the child process will run unimpeded. If you have | |
2861 | set a breakpoint in any code which the child then executes, the child | |
2862 | will get a @code{SIGTRAP} signal which (unless it catches the signal) | |
2863 | will cause it to terminate. | |
c906108c SS |
2864 | |
2865 | However, if you want to debug the child process there is a workaround | |
2866 | which isn't too painful. Put a call to @code{sleep} in the code which | |
2867 | the child process executes after the fork. It may be useful to sleep | |
2868 | only if a certain environment variable is set, or a certain file exists, | |
2869 | so that the delay need not occur when you don't want to run @value{GDBN} | |
2870 | on the child. While the child is sleeping, use the @code{ps} program to | |
2871 | get its process ID. Then tell @value{GDBN} (a new invocation of | |
2872 | @value{GDBN} if you are also debugging the parent process) to attach to | |
d4f3574e | 2873 | the child process (@pxref{Attach}). From that point on you can debug |
c906108c | 2874 | the child process just like any other process which you attached to. |
c906108c | 2875 | |
b51970ac DJ |
2876 | On some systems, @value{GDBN} provides support for debugging programs that |
2877 | create additional processes using the @code{fork} or @code{vfork} functions. | |
2878 | Currently, the only platforms with this feature are HP-UX (11.x and later | |
a6b151f1 | 2879 | only?) and @sc{gnu}/Linux (kernel version 2.5.60 and later). |
c906108c SS |
2880 | |
2881 | By default, when a program forks, @value{GDBN} will continue to debug | |
2882 | the parent process and the child process will run unimpeded. | |
2883 | ||
2884 | If you want to follow the child process instead of the parent process, | |
2885 | use the command @w{@code{set follow-fork-mode}}. | |
2886 | ||
2887 | @table @code | |
2888 | @kindex set follow-fork-mode | |
2889 | @item set follow-fork-mode @var{mode} | |
2890 | Set the debugger response to a program call of @code{fork} or | |
2891 | @code{vfork}. A call to @code{fork} or @code{vfork} creates a new | |
9c16f35a | 2892 | process. The @var{mode} argument can be: |
c906108c SS |
2893 | |
2894 | @table @code | |
2895 | @item parent | |
2896 | The original process is debugged after a fork. The child process runs | |
2df3850c | 2897 | unimpeded. This is the default. |
c906108c SS |
2898 | |
2899 | @item child | |
2900 | The new process is debugged after a fork. The parent process runs | |
2901 | unimpeded. | |
2902 | ||
c906108c SS |
2903 | @end table |
2904 | ||
9c16f35a | 2905 | @kindex show follow-fork-mode |
c906108c | 2906 | @item show follow-fork-mode |
2df3850c | 2907 | Display the current debugger response to a @code{fork} or @code{vfork} call. |
c906108c SS |
2908 | @end table |
2909 | ||
5c95884b MS |
2910 | @cindex debugging multiple processes |
2911 | On Linux, if you want to debug both the parent and child processes, use the | |
2912 | command @w{@code{set detach-on-fork}}. | |
2913 | ||
2914 | @table @code | |
2915 | @kindex set detach-on-fork | |
2916 | @item set detach-on-fork @var{mode} | |
2917 | Tells gdb whether to detach one of the processes after a fork, or | |
2918 | retain debugger control over them both. | |
2919 | ||
2920 | @table @code | |
2921 | @item on | |
2922 | The child process (or parent process, depending on the value of | |
2923 | @code{follow-fork-mode}) will be detached and allowed to run | |
2924 | independently. This is the default. | |
2925 | ||
2926 | @item off | |
2927 | Both processes will be held under the control of @value{GDBN}. | |
2928 | One process (child or parent, depending on the value of | |
2929 | @code{follow-fork-mode}) is debugged as usual, while the other | |
2930 | is held suspended. | |
2931 | ||
2932 | @end table | |
2933 | ||
11310833 NR |
2934 | @kindex show detach-on-fork |
2935 | @item show detach-on-fork | |
2936 | Show whether detach-on-fork mode is on/off. | |
5c95884b MS |
2937 | @end table |
2938 | ||
2277426b PA |
2939 | If you choose to set @samp{detach-on-fork} mode off, then @value{GDBN} |
2940 | will retain control of all forked processes (including nested forks). | |
2941 | You can list the forked processes under the control of @value{GDBN} by | |
2942 | using the @w{@code{info inferiors}} command, and switch from one fork | |
6c95b8df PA |
2943 | to another by using the @code{inferior} command (@pxref{Inferiors and |
2944 | Programs, ,Debugging Multiple Inferiors and Programs}). | |
5c95884b MS |
2945 | |
2946 | To quit debugging one of the forked processes, you can either detach | |
2277426b PA |
2947 | from it by using the @w{@code{detach inferior}} command (allowing it |
2948 | to run independently), or kill it using the @w{@code{kill inferior}} | |
6c95b8df PA |
2949 | command. @xref{Inferiors and Programs, ,Debugging Multiple Inferiors |
2950 | and Programs}. | |
5c95884b | 2951 | |
c906108c SS |
2952 | If you ask to debug a child process and a @code{vfork} is followed by an |
2953 | @code{exec}, @value{GDBN} executes the new target up to the first | |
2954 | breakpoint in the new target. If you have a breakpoint set on | |
2955 | @code{main} in your original program, the breakpoint will also be set on | |
2956 | the child process's @code{main}. | |
2957 | ||
2277426b PA |
2958 | On some systems, when a child process is spawned by @code{vfork}, you |
2959 | cannot debug the child or parent until an @code{exec} call completes. | |
c906108c SS |
2960 | |
2961 | If you issue a @code{run} command to @value{GDBN} after an @code{exec} | |
6c95b8df PA |
2962 | call executes, the new target restarts. To restart the parent |
2963 | process, use the @code{file} command with the parent executable name | |
2964 | as its argument. By default, after an @code{exec} call executes, | |
2965 | @value{GDBN} discards the symbols of the previous executable image. | |
2966 | You can change this behaviour with the @w{@code{set follow-exec-mode}} | |
2967 | command. | |
2968 | ||
2969 | @table @code | |
2970 | @kindex set follow-exec-mode | |
2971 | @item set follow-exec-mode @var{mode} | |
2972 | ||
2973 | Set debugger response to a program call of @code{exec}. An | |
2974 | @code{exec} call replaces the program image of a process. | |
2975 | ||
2976 | @code{follow-exec-mode} can be: | |
2977 | ||
2978 | @table @code | |
2979 | @item new | |
2980 | @value{GDBN} creates a new inferior and rebinds the process to this | |
2981 | new inferior. The program the process was running before the | |
2982 | @code{exec} call can be restarted afterwards by restarting the | |
2983 | original inferior. | |
2984 | ||
2985 | For example: | |
2986 | ||
2987 | @smallexample | |
2988 | (@value{GDBP}) info inferiors | |
2989 | (gdb) info inferior | |
2990 | Id Description Executable | |
2991 | * 1 <null> prog1 | |
2992 | (@value{GDBP}) run | |
2993 | process 12020 is executing new program: prog2 | |
2994 | Program exited normally. | |
2995 | (@value{GDBP}) info inferiors | |
2996 | Id Description Executable | |
2997 | * 2 <null> prog2 | |
2998 | 1 <null> prog1 | |
2999 | @end smallexample | |
3000 | ||
3001 | @item same | |
3002 | @value{GDBN} keeps the process bound to the same inferior. The new | |
3003 | executable image replaces the previous executable loaded in the | |
3004 | inferior. Restarting the inferior after the @code{exec} call, with | |
3005 | e.g., the @code{run} command, restarts the executable the process was | |
3006 | running after the @code{exec} call. This is the default mode. | |
3007 | ||
3008 | For example: | |
3009 | ||
3010 | @smallexample | |
3011 | (@value{GDBP}) info inferiors | |
3012 | Id Description Executable | |
3013 | * 1 <null> prog1 | |
3014 | (@value{GDBP}) run | |
3015 | process 12020 is executing new program: prog2 | |
3016 | Program exited normally. | |
3017 | (@value{GDBP}) info inferiors | |
3018 | Id Description Executable | |
3019 | * 1 <null> prog2 | |
3020 | @end smallexample | |
3021 | ||
3022 | @end table | |
3023 | @end table | |
c906108c SS |
3024 | |
3025 | You can use the @code{catch} command to make @value{GDBN} stop whenever | |
3026 | a @code{fork}, @code{vfork}, or @code{exec} call is made. @xref{Set | |
79a6e687 | 3027 | Catchpoints, ,Setting Catchpoints}. |
c906108c | 3028 | |
5c95884b | 3029 | @node Checkpoint/Restart |
79a6e687 | 3030 | @section Setting a @emph{Bookmark} to Return to Later |
5c95884b MS |
3031 | |
3032 | @cindex checkpoint | |
3033 | @cindex restart | |
3034 | @cindex bookmark | |
3035 | @cindex snapshot of a process | |
3036 | @cindex rewind program state | |
3037 | ||
3038 | On certain operating systems@footnote{Currently, only | |
3039 | @sc{gnu}/Linux.}, @value{GDBN} is able to save a @dfn{snapshot} of a | |
3040 | program's state, called a @dfn{checkpoint}, and come back to it | |
3041 | later. | |
3042 | ||
3043 | Returning to a checkpoint effectively undoes everything that has | |
3044 | happened in the program since the @code{checkpoint} was saved. This | |
3045 | includes changes in memory, registers, and even (within some limits) | |
3046 | system state. Effectively, it is like going back in time to the | |
3047 | moment when the checkpoint was saved. | |
3048 | ||
3049 | Thus, if you're stepping thru a program and you think you're | |
3050 | getting close to the point where things go wrong, you can save | |
3051 | a checkpoint. Then, if you accidentally go too far and miss | |
3052 | the critical statement, instead of having to restart your program | |
3053 | from the beginning, you can just go back to the checkpoint and | |
3054 | start again from there. | |
3055 | ||
3056 | This can be especially useful if it takes a lot of time or | |
3057 | steps to reach the point where you think the bug occurs. | |
3058 | ||
3059 | To use the @code{checkpoint}/@code{restart} method of debugging: | |
3060 | ||
3061 | @table @code | |
3062 | @kindex checkpoint | |
3063 | @item checkpoint | |
3064 | Save a snapshot of the debugged program's current execution state. | |
3065 | The @code{checkpoint} command takes no arguments, but each checkpoint | |
3066 | is assigned a small integer id, similar to a breakpoint id. | |
3067 | ||
3068 | @kindex info checkpoints | |
3069 | @item info checkpoints | |
3070 | List the checkpoints that have been saved in the current debugging | |
3071 | session. For each checkpoint, the following information will be | |
3072 | listed: | |
3073 | ||
3074 | @table @code | |
3075 | @item Checkpoint ID | |
3076 | @item Process ID | |
3077 | @item Code Address | |
3078 | @item Source line, or label | |
3079 | @end table | |
3080 | ||
3081 | @kindex restart @var{checkpoint-id} | |
3082 | @item restart @var{checkpoint-id} | |
3083 | Restore the program state that was saved as checkpoint number | |
3084 | @var{checkpoint-id}. All program variables, registers, stack frames | |
3085 | etc.@: will be returned to the values that they had when the checkpoint | |
3086 | was saved. In essence, gdb will ``wind back the clock'' to the point | |
3087 | in time when the checkpoint was saved. | |
3088 | ||
3089 | Note that breakpoints, @value{GDBN} variables, command history etc. | |
3090 | are not affected by restoring a checkpoint. In general, a checkpoint | |
3091 | only restores things that reside in the program being debugged, not in | |
3092 | the debugger. | |
3093 | ||
b8db102d MS |
3094 | @kindex delete checkpoint @var{checkpoint-id} |
3095 | @item delete checkpoint @var{checkpoint-id} | |
5c95884b MS |
3096 | Delete the previously-saved checkpoint identified by @var{checkpoint-id}. |
3097 | ||
3098 | @end table | |
3099 | ||
3100 | Returning to a previously saved checkpoint will restore the user state | |
3101 | of the program being debugged, plus a significant subset of the system | |
3102 | (OS) state, including file pointers. It won't ``un-write'' data from | |
3103 | a file, but it will rewind the file pointer to the previous location, | |
3104 | so that the previously written data can be overwritten. For files | |
3105 | opened in read mode, the pointer will also be restored so that the | |
3106 | previously read data can be read again. | |
3107 | ||
3108 | Of course, characters that have been sent to a printer (or other | |
3109 | external device) cannot be ``snatched back'', and characters received | |
3110 | from eg.@: a serial device can be removed from internal program buffers, | |
3111 | but they cannot be ``pushed back'' into the serial pipeline, ready to | |
3112 | be received again. Similarly, the actual contents of files that have | |
3113 | been changed cannot be restored (at this time). | |
3114 | ||
3115 | However, within those constraints, you actually can ``rewind'' your | |
3116 | program to a previously saved point in time, and begin debugging it | |
3117 | again --- and you can change the course of events so as to debug a | |
3118 | different execution path this time. | |
3119 | ||
3120 | @cindex checkpoints and process id | |
3121 | Finally, there is one bit of internal program state that will be | |
3122 | different when you return to a checkpoint --- the program's process | |
3123 | id. Each checkpoint will have a unique process id (or @var{pid}), | |
3124 | and each will be different from the program's original @var{pid}. | |
3125 | If your program has saved a local copy of its process id, this could | |
3126 | potentially pose a problem. | |
3127 | ||
79a6e687 | 3128 | @subsection A Non-obvious Benefit of Using Checkpoints |
5c95884b MS |
3129 | |
3130 | On some systems such as @sc{gnu}/Linux, address space randomization | |
3131 | is performed on new processes for security reasons. This makes it | |
3132 | difficult or impossible to set a breakpoint, or watchpoint, on an | |
3133 | absolute address if you have to restart the program, since the | |
3134 | absolute location of a symbol will change from one execution to the | |
3135 | next. | |
3136 | ||
3137 | A checkpoint, however, is an @emph{identical} copy of a process. | |
3138 | Therefore if you create a checkpoint at (eg.@:) the start of main, | |
3139 | and simply return to that checkpoint instead of restarting the | |
3140 | process, you can avoid the effects of address randomization and | |
3141 | your symbols will all stay in the same place. | |
3142 | ||
6d2ebf8b | 3143 | @node Stopping |
c906108c SS |
3144 | @chapter Stopping and Continuing |
3145 | ||
3146 | The principal purposes of using a debugger are so that you can stop your | |
3147 | program before it terminates; or so that, if your program runs into | |
3148 | trouble, you can investigate and find out why. | |
3149 | ||
7a292a7a SS |
3150 | Inside @value{GDBN}, your program may stop for any of several reasons, |
3151 | such as a signal, a breakpoint, or reaching a new line after a | |
3152 | @value{GDBN} command such as @code{step}. You may then examine and | |
3153 | change variables, set new breakpoints or remove old ones, and then | |
3154 | continue execution. Usually, the messages shown by @value{GDBN} provide | |
3155 | ample explanation of the status of your program---but you can also | |
3156 | explicitly request this information at any time. | |
c906108c SS |
3157 | |
3158 | @table @code | |
3159 | @kindex info program | |
3160 | @item info program | |
3161 | Display information about the status of your program: whether it is | |
7a292a7a | 3162 | running or not, what process it is, and why it stopped. |
c906108c SS |
3163 | @end table |
3164 | ||
3165 | @menu | |
3166 | * Breakpoints:: Breakpoints, watchpoints, and catchpoints | |
3167 | * Continuing and Stepping:: Resuming execution | |
c906108c | 3168 | * Signals:: Signals |
c906108c | 3169 | * Thread Stops:: Stopping and starting multi-thread programs |
c906108c SS |
3170 | @end menu |
3171 | ||
6d2ebf8b | 3172 | @node Breakpoints |
79a6e687 | 3173 | @section Breakpoints, Watchpoints, and Catchpoints |
c906108c SS |
3174 | |
3175 | @cindex breakpoints | |
3176 | A @dfn{breakpoint} makes your program stop whenever a certain point in | |
3177 | the program is reached. For each breakpoint, you can add conditions to | |
3178 | control in finer detail whether your program stops. You can set | |
3179 | breakpoints with the @code{break} command and its variants (@pxref{Set | |
79a6e687 | 3180 | Breaks, ,Setting Breakpoints}), to specify the place where your program |
c906108c SS |
3181 | should stop by line number, function name or exact address in the |
3182 | program. | |
3183 | ||
09d4efe1 EZ |
3184 | On some systems, you can set breakpoints in shared libraries before |
3185 | the executable is run. There is a minor limitation on HP-UX systems: | |
3186 | you must wait until the executable is run in order to set breakpoints | |
3187 | in shared library routines that are not called directly by the program | |
3188 | (for example, routines that are arguments in a @code{pthread_create} | |
3189 | call). | |
c906108c SS |
3190 | |
3191 | @cindex watchpoints | |
fd60e0df | 3192 | @cindex data breakpoints |
c906108c SS |
3193 | @cindex memory tracing |
3194 | @cindex breakpoint on memory address | |
3195 | @cindex breakpoint on variable modification | |
3196 | A @dfn{watchpoint} is a special breakpoint that stops your program | |
fd60e0df | 3197 | when the value of an expression changes. The expression may be a value |
0ced0c34 | 3198 | of a variable, or it could involve values of one or more variables |
fd60e0df EZ |
3199 | combined by operators, such as @samp{a + b}. This is sometimes called |
3200 | @dfn{data breakpoints}. You must use a different command to set | |
79a6e687 | 3201 | watchpoints (@pxref{Set Watchpoints, ,Setting Watchpoints}), but aside |
fd60e0df EZ |
3202 | from that, you can manage a watchpoint like any other breakpoint: you |
3203 | enable, disable, and delete both breakpoints and watchpoints using the | |
3204 | same commands. | |
c906108c SS |
3205 | |
3206 | You can arrange to have values from your program displayed automatically | |
3207 | whenever @value{GDBN} stops at a breakpoint. @xref{Auto Display,, | |
79a6e687 | 3208 | Automatic Display}. |
c906108c SS |
3209 | |
3210 | @cindex catchpoints | |
3211 | @cindex breakpoint on events | |
3212 | A @dfn{catchpoint} is another special breakpoint that stops your program | |
b37052ae | 3213 | when a certain kind of event occurs, such as the throwing of a C@t{++} |
c906108c SS |
3214 | exception or the loading of a library. As with watchpoints, you use a |
3215 | different command to set a catchpoint (@pxref{Set Catchpoints, ,Setting | |
79a6e687 | 3216 | Catchpoints}), but aside from that, you can manage a catchpoint like any |
c906108c | 3217 | other breakpoint. (To stop when your program receives a signal, use the |
d4f3574e | 3218 | @code{handle} command; see @ref{Signals, ,Signals}.) |
c906108c SS |
3219 | |
3220 | @cindex breakpoint numbers | |
3221 | @cindex numbers for breakpoints | |
3222 | @value{GDBN} assigns a number to each breakpoint, watchpoint, or | |
3223 | catchpoint when you create it; these numbers are successive integers | |
3224 | starting with one. In many of the commands for controlling various | |
3225 | features of breakpoints you use the breakpoint number to say which | |
3226 | breakpoint you want to change. Each breakpoint may be @dfn{enabled} or | |
3227 | @dfn{disabled}; if disabled, it has no effect on your program until you | |
3228 | enable it again. | |
3229 | ||
c5394b80 JM |
3230 | @cindex breakpoint ranges |
3231 | @cindex ranges of breakpoints | |
3232 | Some @value{GDBN} commands accept a range of breakpoints on which to | |
3233 | operate. A breakpoint range is either a single breakpoint number, like | |
3234 | @samp{5}, or two such numbers, in increasing order, separated by a | |
3235 | hyphen, like @samp{5-7}. When a breakpoint range is given to a command, | |
d52fb0e9 | 3236 | all breakpoints in that range are operated on. |
c5394b80 | 3237 | |
c906108c SS |
3238 | @menu |
3239 | * Set Breaks:: Setting breakpoints | |
3240 | * Set Watchpoints:: Setting watchpoints | |
3241 | * Set Catchpoints:: Setting catchpoints | |
3242 | * Delete Breaks:: Deleting breakpoints | |
3243 | * Disabling:: Disabling breakpoints | |
3244 | * Conditions:: Break conditions | |
3245 | * Break Commands:: Breakpoint command lists | |
d4f3574e | 3246 | * Error in Breakpoints:: ``Cannot insert breakpoints'' |
79a6e687 | 3247 | * Breakpoint-related Warnings:: ``Breakpoint address adjusted...'' |
c906108c SS |
3248 | @end menu |
3249 | ||
6d2ebf8b | 3250 | @node Set Breaks |
79a6e687 | 3251 | @subsection Setting Breakpoints |
c906108c | 3252 | |
5d161b24 | 3253 | @c FIXME LMB what does GDB do if no code on line of breakpt? |
c906108c SS |
3254 | @c consider in particular declaration with/without initialization. |
3255 | @c | |
3256 | @c FIXME 2 is there stuff on this already? break at fun start, already init? | |
3257 | ||
3258 | @kindex break | |
41afff9a EZ |
3259 | @kindex b @r{(@code{break})} |
3260 | @vindex $bpnum@r{, convenience variable} | |
c906108c SS |
3261 | @cindex latest breakpoint |
3262 | Breakpoints are set with the @code{break} command (abbreviated | |
5d161b24 | 3263 | @code{b}). The debugger convenience variable @samp{$bpnum} records the |
f3b28801 | 3264 | number of the breakpoint you've set most recently; see @ref{Convenience |
79a6e687 | 3265 | Vars,, Convenience Variables}, for a discussion of what you can do with |
c906108c SS |
3266 | convenience variables. |
3267 | ||
c906108c | 3268 | @table @code |
2a25a5ba EZ |
3269 | @item break @var{location} |
3270 | Set a breakpoint at the given @var{location}, which can specify a | |
3271 | function name, a line number, or an address of an instruction. | |
3272 | (@xref{Specify Location}, for a list of all the possible ways to | |
3273 | specify a @var{location}.) The breakpoint will stop your program just | |
3274 | before it executes any of the code in the specified @var{location}. | |
3275 | ||
c906108c | 3276 | When using source languages that permit overloading of symbols, such as |
2a25a5ba | 3277 | C@t{++}, a function name may refer to more than one possible place to break. |
6ba66d6a JB |
3278 | @xref{Ambiguous Expressions,,Ambiguous Expressions}, for a discussion of |
3279 | that situation. | |
c906108c | 3280 | |
45ac276d | 3281 | It is also possible to insert a breakpoint that will stop the program |
2c88c651 JB |
3282 | only if a specific thread (@pxref{Thread-Specific Breakpoints}) |
3283 | or a specific task (@pxref{Ada Tasks}) hits that breakpoint. | |
45ac276d | 3284 | |
c906108c SS |
3285 | @item break |
3286 | When called without any arguments, @code{break} sets a breakpoint at | |
3287 | the next instruction to be executed in the selected stack frame | |
3288 | (@pxref{Stack, ,Examining the Stack}). In any selected frame but the | |
3289 | innermost, this makes your program stop as soon as control | |
3290 | returns to that frame. This is similar to the effect of a | |
3291 | @code{finish} command in the frame inside the selected frame---except | |
3292 | that @code{finish} does not leave an active breakpoint. If you use | |
3293 | @code{break} without an argument in the innermost frame, @value{GDBN} stops | |
3294 | the next time it reaches the current location; this may be useful | |
3295 | inside loops. | |
3296 | ||
3297 | @value{GDBN} normally ignores breakpoints when it resumes execution, until at | |
3298 | least one instruction has been executed. If it did not do this, you | |
3299 | would be unable to proceed past a breakpoint without first disabling the | |
3300 | breakpoint. This rule applies whether or not the breakpoint already | |
3301 | existed when your program stopped. | |
3302 | ||
3303 | @item break @dots{} if @var{cond} | |
3304 | Set a breakpoint with condition @var{cond}; evaluate the expression | |
3305 | @var{cond} each time the breakpoint is reached, and stop only if the | |
3306 | value is nonzero---that is, if @var{cond} evaluates as true. | |
3307 | @samp{@dots{}} stands for one of the possible arguments described | |
3308 | above (or no argument) specifying where to break. @xref{Conditions, | |
79a6e687 | 3309 | ,Break Conditions}, for more information on breakpoint conditions. |
c906108c SS |
3310 | |
3311 | @kindex tbreak | |
3312 | @item tbreak @var{args} | |
3313 | Set a breakpoint enabled only for one stop. @var{args} are the | |
3314 | same as for the @code{break} command, and the breakpoint is set in the same | |
3315 | way, but the breakpoint is automatically deleted after the first time your | |
79a6e687 | 3316 | program stops there. @xref{Disabling, ,Disabling Breakpoints}. |
c906108c | 3317 | |
c906108c | 3318 | @kindex hbreak |
ba04e063 | 3319 | @cindex hardware breakpoints |
c906108c | 3320 | @item hbreak @var{args} |
d4f3574e SS |
3321 | Set a hardware-assisted breakpoint. @var{args} are the same as for the |
3322 | @code{break} command and the breakpoint is set in the same way, but the | |
c906108c SS |
3323 | breakpoint requires hardware support and some target hardware may not |
3324 | have this support. The main purpose of this is EPROM/ROM code | |
d4f3574e SS |
3325 | debugging, so you can set a breakpoint at an instruction without |
3326 | changing the instruction. This can be used with the new trap-generation | |
09d4efe1 | 3327 | provided by SPARClite DSU and most x86-based targets. These targets |
d4f3574e SS |
3328 | will generate traps when a program accesses some data or instruction |
3329 | address that is assigned to the debug registers. However the hardware | |
3330 | breakpoint registers can take a limited number of breakpoints. For | |
3331 | example, on the DSU, only two data breakpoints can be set at a time, and | |
3332 | @value{GDBN} will reject this command if more than two are used. Delete | |
3333 | or disable unused hardware breakpoints before setting new ones | |
79a6e687 BW |
3334 | (@pxref{Disabling, ,Disabling Breakpoints}). |
3335 | @xref{Conditions, ,Break Conditions}. | |
9c16f35a EZ |
3336 | For remote targets, you can restrict the number of hardware |
3337 | breakpoints @value{GDBN} will use, see @ref{set remote | |
3338 | hardware-breakpoint-limit}. | |
501eef12 | 3339 | |
c906108c SS |
3340 | @kindex thbreak |
3341 | @item thbreak @var{args} | |
3342 | Set a hardware-assisted breakpoint enabled only for one stop. @var{args} | |
3343 | are the same as for the @code{hbreak} command and the breakpoint is set in | |
5d161b24 | 3344 | the same way. However, like the @code{tbreak} command, |
c906108c SS |
3345 | the breakpoint is automatically deleted after the |
3346 | first time your program stops there. Also, like the @code{hbreak} | |
5d161b24 | 3347 | command, the breakpoint requires hardware support and some target hardware |
79a6e687 BW |
3348 | may not have this support. @xref{Disabling, ,Disabling Breakpoints}. |
3349 | See also @ref{Conditions, ,Break Conditions}. | |
c906108c SS |
3350 | |
3351 | @kindex rbreak | |
3352 | @cindex regular expression | |
c45da7e6 EZ |
3353 | @cindex breakpoints in functions matching a regexp |
3354 | @cindex set breakpoints in many functions | |
c906108c | 3355 | @item rbreak @var{regex} |
c906108c | 3356 | Set breakpoints on all functions matching the regular expression |
11cf8741 JM |
3357 | @var{regex}. This command sets an unconditional breakpoint on all |
3358 | matches, printing a list of all breakpoints it set. Once these | |
3359 | breakpoints are set, they are treated just like the breakpoints set with | |
3360 | the @code{break} command. You can delete them, disable them, or make | |
3361 | them conditional the same way as any other breakpoint. | |
3362 | ||
3363 | The syntax of the regular expression is the standard one used with tools | |
3364 | like @file{grep}. Note that this is different from the syntax used by | |
3365 | shells, so for instance @code{foo*} matches all functions that include | |
3366 | an @code{fo} followed by zero or more @code{o}s. There is an implicit | |
3367 | @code{.*} leading and trailing the regular expression you supply, so to | |
3368 | match only functions that begin with @code{foo}, use @code{^foo}. | |
c906108c | 3369 | |
f7dc1244 | 3370 | @cindex non-member C@t{++} functions, set breakpoint in |
b37052ae | 3371 | When debugging C@t{++} programs, @code{rbreak} is useful for setting |
c906108c SS |
3372 | breakpoints on overloaded functions that are not members of any special |
3373 | classes. | |
c906108c | 3374 | |
f7dc1244 EZ |
3375 | @cindex set breakpoints on all functions |
3376 | The @code{rbreak} command can be used to set breakpoints in | |
3377 | @strong{all} the functions in a program, like this: | |
3378 | ||
3379 | @smallexample | |
3380 | (@value{GDBP}) rbreak . | |
3381 | @end smallexample | |
3382 | ||
c906108c SS |
3383 | @kindex info breakpoints |
3384 | @cindex @code{$_} and @code{info breakpoints} | |
3385 | @item info breakpoints @r{[}@var{n}@r{]} | |
3386 | @itemx info break @r{[}@var{n}@r{]} | |
3387 | @itemx info watchpoints @r{[}@var{n}@r{]} | |
3388 | Print a table of all breakpoints, watchpoints, and catchpoints set and | |
45ac1734 EZ |
3389 | not deleted. Optional argument @var{n} means print information only |
3390 | about the specified breakpoint (or watchpoint or catchpoint). For | |
3391 | each breakpoint, following columns are printed: | |
c906108c SS |
3392 | |
3393 | @table @emph | |
3394 | @item Breakpoint Numbers | |
3395 | @item Type | |
3396 | Breakpoint, watchpoint, or catchpoint. | |
3397 | @item Disposition | |
3398 | Whether the breakpoint is marked to be disabled or deleted when hit. | |
3399 | @item Enabled or Disabled | |
3400 | Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints | |
b3db7447 | 3401 | that are not enabled. |
c906108c | 3402 | @item Address |
fe6fbf8b | 3403 | Where the breakpoint is in your program, as a memory address. For a |
b3db7447 NR |
3404 | pending breakpoint whose address is not yet known, this field will |
3405 | contain @samp{<PENDING>}. Such breakpoint won't fire until a shared | |
3406 | library that has the symbol or line referred by breakpoint is loaded. | |
3407 | See below for details. A breakpoint with several locations will | |
3b784c4f | 3408 | have @samp{<MULTIPLE>} in this field---see below for details. |
c906108c SS |
3409 | @item What |
3410 | Where the breakpoint is in the source for your program, as a file and | |
2650777c JJ |
3411 | line number. For a pending breakpoint, the original string passed to |
3412 | the breakpoint command will be listed as it cannot be resolved until | |
3413 | the appropriate shared library is loaded in the future. | |
c906108c SS |
3414 | @end table |
3415 | ||
3416 | @noindent | |
3417 | If a breakpoint is conditional, @code{info break} shows the condition on | |
3418 | the line following the affected breakpoint; breakpoint commands, if any, | |
2650777c JJ |
3419 | are listed after that. A pending breakpoint is allowed to have a condition |
3420 | specified for it. The condition is not parsed for validity until a shared | |
3421 | library is loaded that allows the pending breakpoint to resolve to a | |
3422 | valid location. | |
c906108c SS |
3423 | |
3424 | @noindent | |
3425 | @code{info break} with a breakpoint | |
3426 | number @var{n} as argument lists only that breakpoint. The | |
3427 | convenience variable @code{$_} and the default examining-address for | |
3428 | the @code{x} command are set to the address of the last breakpoint | |
79a6e687 | 3429 | listed (@pxref{Memory, ,Examining Memory}). |
c906108c SS |
3430 | |
3431 | @noindent | |
3432 | @code{info break} displays a count of the number of times the breakpoint | |
3433 | has been hit. This is especially useful in conjunction with the | |
3434 | @code{ignore} command. You can ignore a large number of breakpoint | |
3435 | hits, look at the breakpoint info to see how many times the breakpoint | |
3436 | was hit, and then run again, ignoring one less than that number. This | |
3437 | will get you quickly to the last hit of that breakpoint. | |
3438 | @end table | |
3439 | ||
3440 | @value{GDBN} allows you to set any number of breakpoints at the same place in | |
3441 | your program. There is nothing silly or meaningless about this. When | |
3442 | the breakpoints are conditional, this is even useful | |
79a6e687 | 3443 | (@pxref{Conditions, ,Break Conditions}). |
c906108c | 3444 | |
2e9132cc EZ |
3445 | @cindex multiple locations, breakpoints |
3446 | @cindex breakpoints, multiple locations | |
fcda367b | 3447 | It is possible that a breakpoint corresponds to several locations |
fe6fbf8b VP |
3448 | in your program. Examples of this situation are: |
3449 | ||
3450 | @itemize @bullet | |
fe6fbf8b VP |
3451 | @item |
3452 | For a C@t{++} constructor, the @value{NGCC} compiler generates several | |
3453 | instances of the function body, used in different cases. | |
3454 | ||
3455 | @item | |
3456 | For a C@t{++} template function, a given line in the function can | |
3457 | correspond to any number of instantiations. | |
3458 | ||
3459 | @item | |
3460 | For an inlined function, a given source line can correspond to | |
3461 | several places where that function is inlined. | |
fe6fbf8b VP |
3462 | @end itemize |
3463 | ||
3464 | In all those cases, @value{GDBN} will insert a breakpoint at all | |
2e9132cc EZ |
3465 | the relevant locations@footnote{ |
3466 | As of this writing, multiple-location breakpoints work only if there's | |
3467 | line number information for all the locations. This means that they | |
3468 | will generally not work in system libraries, unless you have debug | |
3469 | info with line numbers for them.}. | |
fe6fbf8b | 3470 | |
3b784c4f EZ |
3471 | A breakpoint with multiple locations is displayed in the breakpoint |
3472 | table using several rows---one header row, followed by one row for | |
3473 | each breakpoint location. The header row has @samp{<MULTIPLE>} in the | |
3474 | address column. The rows for individual locations contain the actual | |
3475 | addresses for locations, and show the functions to which those | |
3476 | locations belong. The number column for a location is of the form | |
fe6fbf8b VP |
3477 | @var{breakpoint-number}.@var{location-number}. |
3478 | ||
3479 | For example: | |
3b784c4f | 3480 | |
fe6fbf8b VP |
3481 | @smallexample |
3482 | Num Type Disp Enb Address What | |
3483 | 1 breakpoint keep y <MULTIPLE> | |
3484 | stop only if i==1 | |
3485 | breakpoint already hit 1 time | |
3486 | 1.1 y 0x080486a2 in void foo<int>() at t.cc:8 | |
3487 | 1.2 y 0x080486ca in void foo<double>() at t.cc:8 | |
3488 | @end smallexample | |
3489 | ||
3490 | Each location can be individually enabled or disabled by passing | |
3491 | @var{breakpoint-number}.@var{location-number} as argument to the | |
3b784c4f EZ |
3492 | @code{enable} and @code{disable} commands. Note that you cannot |
3493 | delete the individual locations from the list, you can only delete the | |
16bfc218 | 3494 | entire list of locations that belong to their parent breakpoint (with |
3b784c4f EZ |
3495 | the @kbd{delete @var{num}} command, where @var{num} is the number of |
3496 | the parent breakpoint, 1 in the above example). Disabling or enabling | |
3497 | the parent breakpoint (@pxref{Disabling}) affects all of the locations | |
3498 | that belong to that breakpoint. | |
fe6fbf8b | 3499 | |
2650777c | 3500 | @cindex pending breakpoints |
fe6fbf8b | 3501 | It's quite common to have a breakpoint inside a shared library. |
3b784c4f | 3502 | Shared libraries can be loaded and unloaded explicitly, |
fe6fbf8b VP |
3503 | and possibly repeatedly, as the program is executed. To support |
3504 | this use case, @value{GDBN} updates breakpoint locations whenever | |
3505 | any shared library is loaded or unloaded. Typically, you would | |
fcda367b | 3506 | set a breakpoint in a shared library at the beginning of your |
fe6fbf8b VP |
3507 | debugging session, when the library is not loaded, and when the |
3508 | symbols from the library are not available. When you try to set | |
3509 | breakpoint, @value{GDBN} will ask you if you want to set | |
3b784c4f | 3510 | a so called @dfn{pending breakpoint}---breakpoint whose address |
fe6fbf8b VP |
3511 | is not yet resolved. |
3512 | ||
3513 | After the program is run, whenever a new shared library is loaded, | |
3514 | @value{GDBN} reevaluates all the breakpoints. When a newly loaded | |
3515 | shared library contains the symbol or line referred to by some | |
3516 | pending breakpoint, that breakpoint is resolved and becomes an | |
3517 | ordinary breakpoint. When a library is unloaded, all breakpoints | |
3518 | that refer to its symbols or source lines become pending again. | |
3519 | ||
3520 | This logic works for breakpoints with multiple locations, too. For | |
3521 | example, if you have a breakpoint in a C@t{++} template function, and | |
3522 | a newly loaded shared library has an instantiation of that template, | |
3523 | a new location is added to the list of locations for the breakpoint. | |
3524 | ||
3525 | Except for having unresolved address, pending breakpoints do not | |
3526 | differ from regular breakpoints. You can set conditions or commands, | |
3527 | enable and disable them and perform other breakpoint operations. | |
3528 | ||
3529 | @value{GDBN} provides some additional commands for controlling what | |
3530 | happens when the @samp{break} command cannot resolve breakpoint | |
3531 | address specification to an address: | |
dd79a6cf JJ |
3532 | |
3533 | @kindex set breakpoint pending | |
3534 | @kindex show breakpoint pending | |
3535 | @table @code | |
3536 | @item set breakpoint pending auto | |
3537 | This is the default behavior. When @value{GDBN} cannot find the breakpoint | |
3538 | location, it queries you whether a pending breakpoint should be created. | |
3539 | ||
3540 | @item set breakpoint pending on | |
3541 | This indicates that an unrecognized breakpoint location should automatically | |
3542 | result in a pending breakpoint being created. | |
3543 | ||
3544 | @item set breakpoint pending off | |
3545 | This indicates that pending breakpoints are not to be created. Any | |
3546 | unrecognized breakpoint location results in an error. This setting does | |
3547 | not affect any pending breakpoints previously created. | |
3548 | ||
3549 | @item show breakpoint pending | |
3550 | Show the current behavior setting for creating pending breakpoints. | |
3551 | @end table | |
2650777c | 3552 | |
fe6fbf8b VP |
3553 | The settings above only affect the @code{break} command and its |
3554 | variants. Once breakpoint is set, it will be automatically updated | |
3555 | as shared libraries are loaded and unloaded. | |
2650777c | 3556 | |
765dc015 VP |
3557 | @cindex automatic hardware breakpoints |
3558 | For some targets, @value{GDBN} can automatically decide if hardware or | |
3559 | software breakpoints should be used, depending on whether the | |
3560 | breakpoint address is read-only or read-write. This applies to | |
3561 | breakpoints set with the @code{break} command as well as to internal | |
3562 | breakpoints set by commands like @code{next} and @code{finish}. For | |
fcda367b | 3563 | breakpoints set with @code{hbreak}, @value{GDBN} will always use hardware |
765dc015 VP |
3564 | breakpoints. |
3565 | ||
3566 | You can control this automatic behaviour with the following commands:: | |
3567 | ||
3568 | @kindex set breakpoint auto-hw | |
3569 | @kindex show breakpoint auto-hw | |
3570 | @table @code | |
3571 | @item set breakpoint auto-hw on | |
3572 | This is the default behavior. When @value{GDBN} sets a breakpoint, it | |
3573 | will try to use the target memory map to decide if software or hardware | |
3574 | breakpoint must be used. | |
3575 | ||
3576 | @item set breakpoint auto-hw off | |
3577 | This indicates @value{GDBN} should not automatically select breakpoint | |
3578 | type. If the target provides a memory map, @value{GDBN} will warn when | |
3579 | trying to set software breakpoint at a read-only address. | |
3580 | @end table | |
3581 | ||
74960c60 VP |
3582 | @value{GDBN} normally implements breakpoints by replacing the program code |
3583 | at the breakpoint address with a special instruction, which, when | |
3584 | executed, given control to the debugger. By default, the program | |
3585 | code is so modified only when the program is resumed. As soon as | |
3586 | the program stops, @value{GDBN} restores the original instructions. This | |
3587 | behaviour guards against leaving breakpoints inserted in the | |
3588 | target should gdb abrubptly disconnect. However, with slow remote | |
3589 | targets, inserting and removing breakpoint can reduce the performance. | |
3590 | This behavior can be controlled with the following commands:: | |
3591 | ||
3592 | @kindex set breakpoint always-inserted | |
3593 | @kindex show breakpoint always-inserted | |
3594 | @table @code | |
3595 | @item set breakpoint always-inserted off | |
33e5cbd6 PA |
3596 | All breakpoints, including newly added by the user, are inserted in |
3597 | the target only when the target is resumed. All breakpoints are | |
3598 | removed from the target when it stops. | |
74960c60 VP |
3599 | |
3600 | @item set breakpoint always-inserted on | |
3601 | Causes all breakpoints to be inserted in the target at all times. If | |
3602 | the user adds a new breakpoint, or changes an existing breakpoint, the | |
3603 | breakpoints in the target are updated immediately. A breakpoint is | |
3604 | removed from the target only when breakpoint itself is removed. | |
33e5cbd6 PA |
3605 | |
3606 | @cindex non-stop mode, and @code{breakpoint always-inserted} | |
3607 | @item set breakpoint always-inserted auto | |
3608 | This is the default mode. If @value{GDBN} is controlling the inferior | |
3609 | in non-stop mode (@pxref{Non-Stop Mode}), gdb behaves as if | |
3610 | @code{breakpoint always-inserted} mode is on. If @value{GDBN} is | |
3611 | controlling the inferior in all-stop mode, @value{GDBN} behaves as if | |
3612 | @code{breakpoint always-inserted} mode is off. | |
74960c60 | 3613 | @end table |
765dc015 | 3614 | |
c906108c SS |
3615 | @cindex negative breakpoint numbers |
3616 | @cindex internal @value{GDBN} breakpoints | |
eb12ee30 AC |
3617 | @value{GDBN} itself sometimes sets breakpoints in your program for |
3618 | special purposes, such as proper handling of @code{longjmp} (in C | |
3619 | programs). These internal breakpoints are assigned negative numbers, | |
3620 | starting with @code{-1}; @samp{info breakpoints} does not display them. | |
c906108c | 3621 | You can see these breakpoints with the @value{GDBN} maintenance command |
eb12ee30 | 3622 | @samp{maint info breakpoints} (@pxref{maint info breakpoints}). |
c906108c SS |
3623 | |
3624 | ||
6d2ebf8b | 3625 | @node Set Watchpoints |
79a6e687 | 3626 | @subsection Setting Watchpoints |
c906108c SS |
3627 | |
3628 | @cindex setting watchpoints | |
c906108c SS |
3629 | You can use a watchpoint to stop execution whenever the value of an |
3630 | expression changes, without having to predict a particular place where | |
fd60e0df EZ |
3631 | this may happen. (This is sometimes called a @dfn{data breakpoint}.) |
3632 | The expression may be as simple as the value of a single variable, or | |
3633 | as complex as many variables combined by operators. Examples include: | |
3634 | ||
3635 | @itemize @bullet | |
3636 | @item | |
3637 | A reference to the value of a single variable. | |
3638 | ||
3639 | @item | |
3640 | An address cast to an appropriate data type. For example, | |
3641 | @samp{*(int *)0x12345678} will watch a 4-byte region at the specified | |
3642 | address (assuming an @code{int} occupies 4 bytes). | |
3643 | ||
3644 | @item | |
3645 | An arbitrarily complex expression, such as @samp{a*b + c/d}. The | |
3646 | expression can use any operators valid in the program's native | |
3647 | language (@pxref{Languages}). | |
3648 | @end itemize | |
c906108c | 3649 | |
fa4727a6 DJ |
3650 | You can set a watchpoint on an expression even if the expression can |
3651 | not be evaluated yet. For instance, you can set a watchpoint on | |
3652 | @samp{*global_ptr} before @samp{global_ptr} is initialized. | |
3653 | @value{GDBN} will stop when your program sets @samp{global_ptr} and | |
3654 | the expression produces a valid value. If the expression becomes | |
3655 | valid in some other way than changing a variable (e.g.@: if the memory | |
3656 | pointed to by @samp{*global_ptr} becomes readable as the result of a | |
3657 | @code{malloc} call), @value{GDBN} may not stop until the next time | |
3658 | the expression changes. | |
3659 | ||
82f2d802 EZ |
3660 | @cindex software watchpoints |
3661 | @cindex hardware watchpoints | |
c906108c | 3662 | Depending on your system, watchpoints may be implemented in software or |
2df3850c | 3663 | hardware. @value{GDBN} does software watchpointing by single-stepping your |
c906108c SS |
3664 | program and testing the variable's value each time, which is hundreds of |
3665 | times slower than normal execution. (But this may still be worth it, to | |
3666 | catch errors where you have no clue what part of your program is the | |
3667 | culprit.) | |
3668 | ||
37e4754d | 3669 | On some systems, such as HP-UX, PowerPC, @sc{gnu}/Linux and most other |
82f2d802 EZ |
3670 | x86-based targets, @value{GDBN} includes support for hardware |
3671 | watchpoints, which do not slow down the running of your program. | |
c906108c SS |
3672 | |
3673 | @table @code | |
3674 | @kindex watch | |
d8b2a693 | 3675 | @item watch @var{expr} @r{[}thread @var{threadnum}@r{]} |
fd60e0df EZ |
3676 | Set a watchpoint for an expression. @value{GDBN} will break when the |
3677 | expression @var{expr} is written into by the program and its value | |
3678 | changes. The simplest (and the most popular) use of this command is | |
3679 | to watch the value of a single variable: | |
3680 | ||
3681 | @smallexample | |
3682 | (@value{GDBP}) watch foo | |
3683 | @end smallexample | |
c906108c | 3684 | |
d8b2a693 JB |
3685 | If the command includes a @code{@r{[}thread @var{threadnum}@r{]}} |
3686 | clause, @value{GDBN} breaks only when the thread identified by | |
3687 | @var{threadnum} changes the value of @var{expr}. If any other threads | |
3688 | change the value of @var{expr}, @value{GDBN} will not break. Note | |
3689 | that watchpoints restricted to a single thread in this way only work | |
3690 | with Hardware Watchpoints. | |
3691 | ||
c906108c | 3692 | @kindex rwatch |
d8b2a693 | 3693 | @item rwatch @var{expr} @r{[}thread @var{threadnum}@r{]} |
09d4efe1 EZ |
3694 | Set a watchpoint that will break when the value of @var{expr} is read |
3695 | by the program. | |
c906108c SS |
3696 | |
3697 | @kindex awatch | |
d8b2a693 | 3698 | @item awatch @var{expr} @r{[}thread @var{threadnum}@r{]} |
09d4efe1 EZ |
3699 | Set a watchpoint that will break when @var{expr} is either read from |
3700 | or written into by the program. | |
c906108c | 3701 | |
45ac1734 | 3702 | @kindex info watchpoints @r{[}@var{n}@r{]} |
c906108c SS |
3703 | @item info watchpoints |
3704 | This command prints a list of watchpoints, breakpoints, and catchpoints; | |
09d4efe1 | 3705 | it is the same as @code{info break} (@pxref{Set Breaks}). |
c906108c SS |
3706 | @end table |
3707 | ||
3708 | @value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware | |
3709 | watchpoints execute very quickly, and the debugger reports a change in | |
3710 | value at the exact instruction where the change occurs. If @value{GDBN} | |
3711 | cannot set a hardware watchpoint, it sets a software watchpoint, which | |
3712 | executes more slowly and reports the change in value at the next | |
82f2d802 EZ |
3713 | @emph{statement}, not the instruction, after the change occurs. |
3714 | ||
82f2d802 EZ |
3715 | @cindex use only software watchpoints |
3716 | You can force @value{GDBN} to use only software watchpoints with the | |
3717 | @kbd{set can-use-hw-watchpoints 0} command. With this variable set to | |
3718 | zero, @value{GDBN} will never try to use hardware watchpoints, even if | |
3719 | the underlying system supports them. (Note that hardware-assisted | |
3720 | watchpoints that were set @emph{before} setting | |
3721 | @code{can-use-hw-watchpoints} to zero will still use the hardware | |
d3e8051b | 3722 | mechanism of watching expression values.) |
c906108c | 3723 | |
9c16f35a EZ |
3724 | @table @code |
3725 | @item set can-use-hw-watchpoints | |
3726 | @kindex set can-use-hw-watchpoints | |
3727 | Set whether or not to use hardware watchpoints. | |
3728 | ||
3729 | @item show can-use-hw-watchpoints | |
3730 | @kindex show can-use-hw-watchpoints | |
3731 | Show the current mode of using hardware watchpoints. | |
3732 | @end table | |
3733 | ||
3734 | For remote targets, you can restrict the number of hardware | |
3735 | watchpoints @value{GDBN} will use, see @ref{set remote | |
3736 | hardware-breakpoint-limit}. | |
3737 | ||
c906108c SS |
3738 | When you issue the @code{watch} command, @value{GDBN} reports |
3739 | ||
474c8240 | 3740 | @smallexample |
c906108c | 3741 | Hardware watchpoint @var{num}: @var{expr} |
474c8240 | 3742 | @end smallexample |
c906108c SS |
3743 | |
3744 | @noindent | |
3745 | if it was able to set a hardware watchpoint. | |
3746 | ||
7be570e7 JM |
3747 | Currently, the @code{awatch} and @code{rwatch} commands can only set |
3748 | hardware watchpoints, because accesses to data that don't change the | |
3749 | value of the watched expression cannot be detected without examining | |
3750 | every instruction as it is being executed, and @value{GDBN} does not do | |
3751 | that currently. If @value{GDBN} finds that it is unable to set a | |
3752 | hardware breakpoint with the @code{awatch} or @code{rwatch} command, it | |
3753 | will print a message like this: | |
3754 | ||
3755 | @smallexample | |
3756 | Expression cannot be implemented with read/access watchpoint. | |
3757 | @end smallexample | |
3758 | ||
3759 | Sometimes, @value{GDBN} cannot set a hardware watchpoint because the | |
3760 | data type of the watched expression is wider than what a hardware | |
3761 | watchpoint on the target machine can handle. For example, some systems | |
3762 | can only watch regions that are up to 4 bytes wide; on such systems you | |
3763 | cannot set hardware watchpoints for an expression that yields a | |
3764 | double-precision floating-point number (which is typically 8 bytes | |
3765 | wide). As a work-around, it might be possible to break the large region | |
3766 | into a series of smaller ones and watch them with separate watchpoints. | |
3767 | ||
3768 | If you set too many hardware watchpoints, @value{GDBN} might be unable | |
3769 | to insert all of them when you resume the execution of your program. | |
3770 | Since the precise number of active watchpoints is unknown until such | |
3771 | time as the program is about to be resumed, @value{GDBN} might not be | |
3772 | able to warn you about this when you set the watchpoints, and the | |
3773 | warning will be printed only when the program is resumed: | |
3774 | ||
3775 | @smallexample | |
3776 | Hardware watchpoint @var{num}: Could not insert watchpoint | |
3777 | @end smallexample | |
3778 | ||
3779 | @noindent | |
3780 | If this happens, delete or disable some of the watchpoints. | |
3781 | ||
fd60e0df EZ |
3782 | Watching complex expressions that reference many variables can also |
3783 | exhaust the resources available for hardware-assisted watchpoints. | |
3784 | That's because @value{GDBN} needs to watch every variable in the | |
3785 | expression with separately allocated resources. | |
3786 | ||
c906108c | 3787 | If you call a function interactively using @code{print} or @code{call}, |
2df3850c | 3788 | any watchpoints you have set will be inactive until @value{GDBN} reaches another |
c906108c SS |
3789 | kind of breakpoint or the call completes. |
3790 | ||
7be570e7 JM |
3791 | @value{GDBN} automatically deletes watchpoints that watch local |
3792 | (automatic) variables, or expressions that involve such variables, when | |
3793 | they go out of scope, that is, when the execution leaves the block in | |
3794 | which these variables were defined. In particular, when the program | |
3795 | being debugged terminates, @emph{all} local variables go out of scope, | |
3796 | and so only watchpoints that watch global variables remain set. If you | |
3797 | rerun the program, you will need to set all such watchpoints again. One | |
3798 | way of doing that would be to set a code breakpoint at the entry to the | |
3799 | @code{main} function and when it breaks, set all the watchpoints. | |
3800 | ||
c906108c SS |
3801 | @cindex watchpoints and threads |
3802 | @cindex threads and watchpoints | |
d983da9c DJ |
3803 | In multi-threaded programs, watchpoints will detect changes to the |
3804 | watched expression from every thread. | |
3805 | ||
3806 | @quotation | |
3807 | @emph{Warning:} In multi-threaded programs, software watchpoints | |
53a5351d JM |
3808 | have only limited usefulness. If @value{GDBN} creates a software |
3809 | watchpoint, it can only watch the value of an expression @emph{in a | |
3810 | single thread}. If you are confident that the expression can only | |
3811 | change due to the current thread's activity (and if you are also | |
3812 | confident that no other thread can become current), then you can use | |
3813 | software watchpoints as usual. However, @value{GDBN} may not notice | |
3814 | when a non-current thread's activity changes the expression. (Hardware | |
3815 | watchpoints, in contrast, watch an expression in all threads.) | |
c906108c | 3816 | @end quotation |
c906108c | 3817 | |
501eef12 AC |
3818 | @xref{set remote hardware-watchpoint-limit}. |
3819 | ||
6d2ebf8b | 3820 | @node Set Catchpoints |
79a6e687 | 3821 | @subsection Setting Catchpoints |
d4f3574e | 3822 | @cindex catchpoints, setting |
c906108c SS |
3823 | @cindex exception handlers |
3824 | @cindex event handling | |
3825 | ||
3826 | You can use @dfn{catchpoints} to cause the debugger to stop for certain | |
b37052ae | 3827 | kinds of program events, such as C@t{++} exceptions or the loading of a |
c906108c SS |
3828 | shared library. Use the @code{catch} command to set a catchpoint. |
3829 | ||
3830 | @table @code | |
3831 | @kindex catch | |
3832 | @item catch @var{event} | |
3833 | Stop when @var{event} occurs. @var{event} can be any of the following: | |
3834 | @table @code | |
3835 | @item throw | |
4644b6e3 | 3836 | @cindex stop on C@t{++} exceptions |
b37052ae | 3837 | The throwing of a C@t{++} exception. |
c906108c SS |
3838 | |
3839 | @item catch | |
b37052ae | 3840 | The catching of a C@t{++} exception. |
c906108c | 3841 | |
8936fcda JB |
3842 | @item exception |
3843 | @cindex Ada exception catching | |
3844 | @cindex catch Ada exceptions | |
3845 | An Ada exception being raised. If an exception name is specified | |
3846 | at the end of the command (eg @code{catch exception Program_Error}), | |
3847 | the debugger will stop only when this specific exception is raised. | |
3848 | Otherwise, the debugger stops execution when any Ada exception is raised. | |
3849 | ||
87f67dba JB |
3850 | When inserting an exception catchpoint on a user-defined exception whose |
3851 | name is identical to one of the exceptions defined by the language, the | |
3852 | fully qualified name must be used as the exception name. Otherwise, | |
3853 | @value{GDBN} will assume that it should stop on the pre-defined exception | |
3854 | rather than the user-defined one. For instance, assuming an exception | |
3855 | called @code{Constraint_Error} is defined in package @code{Pck}, then | |
3856 | the command to use to catch such exceptions is @kbd{catch exception | |
3857 | Pck.Constraint_Error}. | |
3858 | ||
8936fcda JB |
3859 | @item exception unhandled |
3860 | An exception that was raised but is not handled by the program. | |
3861 | ||
3862 | @item assert | |
3863 | A failed Ada assertion. | |
3864 | ||
c906108c | 3865 | @item exec |
4644b6e3 | 3866 | @cindex break on fork/exec |
5ee187d7 DJ |
3867 | A call to @code{exec}. This is currently only available for HP-UX |
3868 | and @sc{gnu}/Linux. | |
c906108c | 3869 | |
a96d9b2e SDJ |
3870 | @item syscall |
3871 | @itemx syscall @r{[}@var{name} @r{|} @var{number}@r{]} @r{...} | |
3872 | @cindex break on a system call. | |
3873 | A call to or return from a system call, a.k.a.@: @dfn{syscall}. A | |
3874 | syscall is a mechanism for application programs to request a service | |
3875 | from the operating system (OS) or one of the OS system services. | |
3876 | @value{GDBN} can catch some or all of the syscalls issued by the | |
3877 | debuggee, and show the related information for each syscall. If no | |
3878 | argument is specified, calls to and returns from all system calls | |
3879 | will be caught. | |
3880 | ||
3881 | @var{name} can be any system call name that is valid for the | |
3882 | underlying OS. Just what syscalls are valid depends on the OS. On | |
3883 | GNU and Unix systems, you can find the full list of valid syscall | |
3884 | names on @file{/usr/include/asm/unistd.h}. | |
3885 | ||
3886 | @c For MS-Windows, the syscall names and the corresponding numbers | |
3887 | @c can be found, e.g., on this URL: | |
3888 | @c http://www.metasploit.com/users/opcode/syscalls.html | |
3889 | @c but we don't support Windows syscalls yet. | |
3890 | ||
3891 | Normally, @value{GDBN} knows in advance which syscalls are valid for | |
3892 | each OS, so you can use the @value{GDBN} command-line completion | |
3893 | facilities (@pxref{Completion,, command completion}) to list the | |
3894 | available choices. | |
3895 | ||
3896 | You may also specify the system call numerically. A syscall's | |
3897 | number is the value passed to the OS's syscall dispatcher to | |
3898 | identify the requested service. When you specify the syscall by its | |
3899 | name, @value{GDBN} uses its database of syscalls to convert the name | |
3900 | into the corresponding numeric code, but using the number directly | |
3901 | may be useful if @value{GDBN}'s database does not have the complete | |
3902 | list of syscalls on your system (e.g., because @value{GDBN} lags | |
3903 | behind the OS upgrades). | |
3904 | ||
3905 | The example below illustrates how this command works if you don't provide | |
3906 | arguments to it: | |
3907 | ||
3908 | @smallexample | |
3909 | (@value{GDBP}) catch syscall | |
3910 | Catchpoint 1 (syscall) | |
3911 | (@value{GDBP}) r | |
3912 | Starting program: /tmp/catch-syscall | |
3913 | ||
3914 | Catchpoint 1 (call to syscall 'close'), \ | |
3915 | 0xffffe424 in __kernel_vsyscall () | |
3916 | (@value{GDBP}) c | |
3917 | Continuing. | |
3918 | ||
3919 | Catchpoint 1 (returned from syscall 'close'), \ | |
3920 | 0xffffe424 in __kernel_vsyscall () | |
3921 | (@value{GDBP}) | |
3922 | @end smallexample | |
3923 | ||
3924 | Here is an example of catching a system call by name: | |
3925 | ||
3926 | @smallexample | |
3927 | (@value{GDBP}) catch syscall chroot | |
3928 | Catchpoint 1 (syscall 'chroot' [61]) | |
3929 | (@value{GDBP}) r | |
3930 | Starting program: /tmp/catch-syscall | |
3931 | ||
3932 | Catchpoint 1 (call to syscall 'chroot'), \ | |
3933 | 0xffffe424 in __kernel_vsyscall () | |
3934 | (@value{GDBP}) c | |
3935 | Continuing. | |
3936 | ||
3937 | Catchpoint 1 (returned from syscall 'chroot'), \ | |
3938 | 0xffffe424 in __kernel_vsyscall () | |
3939 | (@value{GDBP}) | |
3940 | @end smallexample | |
3941 | ||
3942 | An example of specifying a system call numerically. In the case | |
3943 | below, the syscall number has a corresponding entry in the XML | |
3944 | file, so @value{GDBN} finds its name and prints it: | |
3945 | ||
3946 | @smallexample | |
3947 | (@value{GDBP}) catch syscall 252 | |
3948 | Catchpoint 1 (syscall(s) 'exit_group') | |
3949 | (@value{GDBP}) r | |
3950 | Starting program: /tmp/catch-syscall | |
3951 | ||
3952 | Catchpoint 1 (call to syscall 'exit_group'), \ | |
3953 | 0xffffe424 in __kernel_vsyscall () | |
3954 | (@value{GDBP}) c | |
3955 | Continuing. | |
3956 | ||
3957 | Program exited normally. | |
3958 | (@value{GDBP}) | |
3959 | @end smallexample | |
3960 | ||
3961 | However, there can be situations when there is no corresponding name | |
3962 | in XML file for that syscall number. In this case, @value{GDBN} prints | |
3963 | a warning message saying that it was not able to find the syscall name, | |
3964 | but the catchpoint will be set anyway. See the example below: | |
3965 | ||
3966 | @smallexample | |
3967 | (@value{GDBP}) catch syscall 764 | |
3968 | warning: The number '764' does not represent a known syscall. | |
3969 | Catchpoint 2 (syscall 764) | |
3970 | (@value{GDBP}) | |
3971 | @end smallexample | |
3972 | ||
3973 | If you configure @value{GDBN} using the @samp{--without-expat} option, | |
3974 | it will not be able to display syscall names. Also, if your | |
3975 | architecture does not have an XML file describing its system calls, | |
3976 | you will not be able to see the syscall names. It is important to | |
3977 | notice that these two features are used for accessing the syscall | |
3978 | name database. In either case, you will see a warning like this: | |
3979 | ||
3980 | @smallexample | |
3981 | (@value{GDBP}) catch syscall | |
3982 | warning: Could not open "syscalls/i386-linux.xml" | |
3983 | warning: Could not load the syscall XML file 'syscalls/i386-linux.xml'. | |
3984 | GDB will not be able to display syscall names. | |
3985 | Catchpoint 1 (syscall) | |
3986 | (@value{GDBP}) | |
3987 | @end smallexample | |
3988 | ||
3989 | Of course, the file name will change depending on your architecture and system. | |
3990 | ||
3991 | Still using the example above, you can also try to catch a syscall by its | |
3992 | number. In this case, you would see something like: | |
3993 | ||
3994 | @smallexample | |
3995 | (@value{GDBP}) catch syscall 252 | |
3996 | Catchpoint 1 (syscall(s) 252) | |
3997 | @end smallexample | |
3998 | ||
3999 | Again, in this case @value{GDBN} would not be able to display syscall's names. | |
4000 | ||
c906108c | 4001 | @item fork |
5ee187d7 DJ |
4002 | A call to @code{fork}. This is currently only available for HP-UX |
4003 | and @sc{gnu}/Linux. | |
c906108c SS |
4004 | |
4005 | @item vfork | |
5ee187d7 DJ |
4006 | A call to @code{vfork}. This is currently only available for HP-UX |
4007 | and @sc{gnu}/Linux. | |
c906108c | 4008 | |
c906108c SS |
4009 | @end table |
4010 | ||
4011 | @item tcatch @var{event} | |
4012 | Set a catchpoint that is enabled only for one stop. The catchpoint is | |
4013 | automatically deleted after the first time the event is caught. | |
4014 | ||
4015 | @end table | |
4016 | ||
4017 | Use the @code{info break} command to list the current catchpoints. | |
4018 | ||
b37052ae | 4019 | There are currently some limitations to C@t{++} exception handling |
c906108c SS |
4020 | (@code{catch throw} and @code{catch catch}) in @value{GDBN}: |
4021 | ||
4022 | @itemize @bullet | |
4023 | @item | |
4024 | If you call a function interactively, @value{GDBN} normally returns | |
4025 | control to you when the function has finished executing. If the call | |
4026 | raises an exception, however, the call may bypass the mechanism that | |
4027 | returns control to you and cause your program either to abort or to | |
4028 | simply continue running until it hits a breakpoint, catches a signal | |
4029 | that @value{GDBN} is listening for, or exits. This is the case even if | |
4030 | you set a catchpoint for the exception; catchpoints on exceptions are | |
4031 | disabled within interactive calls. | |
4032 | ||
4033 | @item | |
4034 | You cannot raise an exception interactively. | |
4035 | ||
4036 | @item | |
4037 | You cannot install an exception handler interactively. | |
4038 | @end itemize | |
4039 | ||
4040 | @cindex raise exceptions | |
4041 | Sometimes @code{catch} is not the best way to debug exception handling: | |
4042 | if you need to know exactly where an exception is raised, it is better to | |
4043 | stop @emph{before} the exception handler is called, since that way you | |
4044 | can see the stack before any unwinding takes place. If you set a | |
4045 | breakpoint in an exception handler instead, it may not be easy to find | |
4046 | out where the exception was raised. | |
4047 | ||
4048 | To stop just before an exception handler is called, you need some | |
b37052ae | 4049 | knowledge of the implementation. In the case of @sc{gnu} C@t{++}, exceptions are |
c906108c SS |
4050 | raised by calling a library function named @code{__raise_exception} |
4051 | which has the following ANSI C interface: | |
4052 | ||
474c8240 | 4053 | @smallexample |
c906108c | 4054 | /* @var{addr} is where the exception identifier is stored. |
d4f3574e SS |
4055 | @var{id} is the exception identifier. */ |
4056 | void __raise_exception (void **addr, void *id); | |
474c8240 | 4057 | @end smallexample |
c906108c SS |
4058 | |
4059 | @noindent | |
4060 | To make the debugger catch all exceptions before any stack | |
4061 | unwinding takes place, set a breakpoint on @code{__raise_exception} | |
79a6e687 | 4062 | (@pxref{Breakpoints, ,Breakpoints; Watchpoints; and Exceptions}). |
c906108c | 4063 | |
79a6e687 | 4064 | With a conditional breakpoint (@pxref{Conditions, ,Break Conditions}) |
c906108c SS |
4065 | that depends on the value of @var{id}, you can stop your program when |
4066 | a specific exception is raised. You can use multiple conditional | |
4067 | breakpoints to stop your program when any of a number of exceptions are | |
4068 | raised. | |
4069 | ||
4070 | ||
6d2ebf8b | 4071 | @node Delete Breaks |
79a6e687 | 4072 | @subsection Deleting Breakpoints |
c906108c SS |
4073 | |
4074 | @cindex clearing breakpoints, watchpoints, catchpoints | |
4075 | @cindex deleting breakpoints, watchpoints, catchpoints | |
4076 | It is often necessary to eliminate a breakpoint, watchpoint, or | |
4077 | catchpoint once it has done its job and you no longer want your program | |
4078 | to stop there. This is called @dfn{deleting} the breakpoint. A | |
4079 | breakpoint that has been deleted no longer exists; it is forgotten. | |
4080 | ||
4081 | With the @code{clear} command you can delete breakpoints according to | |
4082 | where they are in your program. With the @code{delete} command you can | |
4083 | delete individual breakpoints, watchpoints, or catchpoints by specifying | |
4084 | their breakpoint numbers. | |
4085 | ||
4086 | It is not necessary to delete a breakpoint to proceed past it. @value{GDBN} | |
4087 | automatically ignores breakpoints on the first instruction to be executed | |
4088 | when you continue execution without changing the execution address. | |
4089 | ||
4090 | @table @code | |
4091 | @kindex clear | |
4092 | @item clear | |
4093 | Delete any breakpoints at the next instruction to be executed in the | |
79a6e687 | 4094 | selected stack frame (@pxref{Selection, ,Selecting a Frame}). When |
c906108c SS |
4095 | the innermost frame is selected, this is a good way to delete a |
4096 | breakpoint where your program just stopped. | |
4097 | ||
2a25a5ba EZ |
4098 | @item clear @var{location} |
4099 | Delete any breakpoints set at the specified @var{location}. | |
4100 | @xref{Specify Location}, for the various forms of @var{location}; the | |
4101 | most useful ones are listed below: | |
4102 | ||
4103 | @table @code | |
c906108c SS |
4104 | @item clear @var{function} |
4105 | @itemx clear @var{filename}:@var{function} | |
09d4efe1 | 4106 | Delete any breakpoints set at entry to the named @var{function}. |
c906108c SS |
4107 | |
4108 | @item clear @var{linenum} | |
4109 | @itemx clear @var{filename}:@var{linenum} | |
09d4efe1 EZ |
4110 | Delete any breakpoints set at or within the code of the specified |
4111 | @var{linenum} of the specified @var{filename}. | |
2a25a5ba | 4112 | @end table |
c906108c SS |
4113 | |
4114 | @cindex delete breakpoints | |
4115 | @kindex delete | |
41afff9a | 4116 | @kindex d @r{(@code{delete})} |
c5394b80 JM |
4117 | @item delete @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
4118 | Delete the breakpoints, watchpoints, or catchpoints of the breakpoint | |
4119 | ranges specified as arguments. If no argument is specified, delete all | |
c906108c SS |
4120 | breakpoints (@value{GDBN} asks confirmation, unless you have @code{set |
4121 | confirm off}). You can abbreviate this command as @code{d}. | |
4122 | @end table | |
4123 | ||
6d2ebf8b | 4124 | @node Disabling |
79a6e687 | 4125 | @subsection Disabling Breakpoints |
c906108c | 4126 | |
4644b6e3 | 4127 | @cindex enable/disable a breakpoint |
c906108c SS |
4128 | Rather than deleting a breakpoint, watchpoint, or catchpoint, you might |
4129 | prefer to @dfn{disable} it. This makes the breakpoint inoperative as if | |
4130 | it had been deleted, but remembers the information on the breakpoint so | |
4131 | that you can @dfn{enable} it again later. | |
4132 | ||
4133 | You disable and enable breakpoints, watchpoints, and catchpoints with | |
4134 | the @code{enable} and @code{disable} commands, optionally specifying one | |
4135 | or more breakpoint numbers as arguments. Use @code{info break} or | |
4136 | @code{info watch} to print a list of breakpoints, watchpoints, and | |
4137 | catchpoints if you do not know which numbers to use. | |
4138 | ||
3b784c4f EZ |
4139 | Disabling and enabling a breakpoint that has multiple locations |
4140 | affects all of its locations. | |
4141 | ||
c906108c SS |
4142 | A breakpoint, watchpoint, or catchpoint can have any of four different |
4143 | states of enablement: | |
4144 | ||
4145 | @itemize @bullet | |
4146 | @item | |
4147 | Enabled. The breakpoint stops your program. A breakpoint set | |
4148 | with the @code{break} command starts out in this state. | |
4149 | @item | |
4150 | Disabled. The breakpoint has no effect on your program. | |
4151 | @item | |
4152 | Enabled once. The breakpoint stops your program, but then becomes | |
d4f3574e | 4153 | disabled. |
c906108c SS |
4154 | @item |
4155 | Enabled for deletion. The breakpoint stops your program, but | |
d4f3574e SS |
4156 | immediately after it does so it is deleted permanently. A breakpoint |
4157 | set with the @code{tbreak} command starts out in this state. | |
c906108c SS |
4158 | @end itemize |
4159 | ||
4160 | You can use the following commands to enable or disable breakpoints, | |
4161 | watchpoints, and catchpoints: | |
4162 | ||
4163 | @table @code | |
c906108c | 4164 | @kindex disable |
41afff9a | 4165 | @kindex dis @r{(@code{disable})} |
c5394b80 | 4166 | @item disable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
4167 | Disable the specified breakpoints---or all breakpoints, if none are |
4168 | listed. A disabled breakpoint has no effect but is not forgotten. All | |
4169 | options such as ignore-counts, conditions and commands are remembered in | |
4170 | case the breakpoint is enabled again later. You may abbreviate | |
4171 | @code{disable} as @code{dis}. | |
4172 | ||
c906108c | 4173 | @kindex enable |
c5394b80 | 4174 | @item enable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
4175 | Enable the specified breakpoints (or all defined breakpoints). They |
4176 | become effective once again in stopping your program. | |
4177 | ||
c5394b80 | 4178 | @item enable @r{[}breakpoints@r{]} once @var{range}@dots{} |
c906108c SS |
4179 | Enable the specified breakpoints temporarily. @value{GDBN} disables any |
4180 | of these breakpoints immediately after stopping your program. | |
4181 | ||
c5394b80 | 4182 | @item enable @r{[}breakpoints@r{]} delete @var{range}@dots{} |
c906108c SS |
4183 | Enable the specified breakpoints to work once, then die. @value{GDBN} |
4184 | deletes any of these breakpoints as soon as your program stops there. | |
09d4efe1 | 4185 | Breakpoints set by the @code{tbreak} command start out in this state. |
c906108c SS |
4186 | @end table |
4187 | ||
d4f3574e SS |
4188 | @c FIXME: I think the following ``Except for [...] @code{tbreak}'' is |
4189 | @c confusing: tbreak is also initially enabled. | |
c906108c | 4190 | Except for a breakpoint set with @code{tbreak} (@pxref{Set Breaks, |
79a6e687 | 4191 | ,Setting Breakpoints}), breakpoints that you set are initially enabled; |
c906108c SS |
4192 | subsequently, they become disabled or enabled only when you use one of |
4193 | the commands above. (The command @code{until} can set and delete a | |
4194 | breakpoint of its own, but it does not change the state of your other | |
4195 | breakpoints; see @ref{Continuing and Stepping, ,Continuing and | |
79a6e687 | 4196 | Stepping}.) |
c906108c | 4197 | |
6d2ebf8b | 4198 | @node Conditions |
79a6e687 | 4199 | @subsection Break Conditions |
c906108c SS |
4200 | @cindex conditional breakpoints |
4201 | @cindex breakpoint conditions | |
4202 | ||
4203 | @c FIXME what is scope of break condition expr? Context where wanted? | |
5d161b24 | 4204 | @c in particular for a watchpoint? |
c906108c SS |
4205 | The simplest sort of breakpoint breaks every time your program reaches a |
4206 | specified place. You can also specify a @dfn{condition} for a | |
4207 | breakpoint. A condition is just a Boolean expression in your | |
4208 | programming language (@pxref{Expressions, ,Expressions}). A breakpoint with | |
4209 | a condition evaluates the expression each time your program reaches it, | |
4210 | and your program stops only if the condition is @emph{true}. | |
4211 | ||
4212 | This is the converse of using assertions for program validation; in that | |
4213 | situation, you want to stop when the assertion is violated---that is, | |
4214 | when the condition is false. In C, if you want to test an assertion expressed | |
4215 | by the condition @var{assert}, you should set the condition | |
4216 | @samp{! @var{assert}} on the appropriate breakpoint. | |
4217 | ||
4218 | Conditions are also accepted for watchpoints; you may not need them, | |
4219 | since a watchpoint is inspecting the value of an expression anyhow---but | |
4220 | it might be simpler, say, to just set a watchpoint on a variable name, | |
4221 | and specify a condition that tests whether the new value is an interesting | |
4222 | one. | |
4223 | ||
4224 | Break conditions can have side effects, and may even call functions in | |
4225 | your program. This can be useful, for example, to activate functions | |
4226 | that log program progress, or to use your own print functions to | |
99e008fe | 4227 | format special data structures. The effects are completely predictable |
c906108c SS |
4228 | unless there is another enabled breakpoint at the same address. (In |
4229 | that case, @value{GDBN} might see the other breakpoint first and stop your | |
4230 | program without checking the condition of this one.) Note that | |
d4f3574e SS |
4231 | breakpoint commands are usually more convenient and flexible than break |
4232 | conditions for the | |
c906108c | 4233 | purpose of performing side effects when a breakpoint is reached |
79a6e687 | 4234 | (@pxref{Break Commands, ,Breakpoint Command Lists}). |
c906108c SS |
4235 | |
4236 | Break conditions can be specified when a breakpoint is set, by using | |
4237 | @samp{if} in the arguments to the @code{break} command. @xref{Set | |
79a6e687 | 4238 | Breaks, ,Setting Breakpoints}. They can also be changed at any time |
c906108c | 4239 | with the @code{condition} command. |
53a5351d | 4240 | |
c906108c SS |
4241 | You can also use the @code{if} keyword with the @code{watch} command. |
4242 | The @code{catch} command does not recognize the @code{if} keyword; | |
4243 | @code{condition} is the only way to impose a further condition on a | |
4244 | catchpoint. | |
c906108c SS |
4245 | |
4246 | @table @code | |
4247 | @kindex condition | |
4248 | @item condition @var{bnum} @var{expression} | |
4249 | Specify @var{expression} as the break condition for breakpoint, | |
4250 | watchpoint, or catchpoint number @var{bnum}. After you set a condition, | |
4251 | breakpoint @var{bnum} stops your program only if the value of | |
4252 | @var{expression} is true (nonzero, in C). When you use | |
4253 | @code{condition}, @value{GDBN} checks @var{expression} immediately for | |
4254 | syntactic correctness, and to determine whether symbols in it have | |
d4f3574e SS |
4255 | referents in the context of your breakpoint. If @var{expression} uses |
4256 | symbols not referenced in the context of the breakpoint, @value{GDBN} | |
4257 | prints an error message: | |
4258 | ||
474c8240 | 4259 | @smallexample |
d4f3574e | 4260 | No symbol "foo" in current context. |
474c8240 | 4261 | @end smallexample |
d4f3574e SS |
4262 | |
4263 | @noindent | |
c906108c SS |
4264 | @value{GDBN} does |
4265 | not actually evaluate @var{expression} at the time the @code{condition} | |
d4f3574e SS |
4266 | command (or a command that sets a breakpoint with a condition, like |
4267 | @code{break if @dots{}}) is given, however. @xref{Expressions, ,Expressions}. | |
c906108c SS |
4268 | |
4269 | @item condition @var{bnum} | |
4270 | Remove the condition from breakpoint number @var{bnum}. It becomes | |
4271 | an ordinary unconditional breakpoint. | |
4272 | @end table | |
4273 | ||
4274 | @cindex ignore count (of breakpoint) | |
4275 | A special case of a breakpoint condition is to stop only when the | |
4276 | breakpoint has been reached a certain number of times. This is so | |
4277 | useful that there is a special way to do it, using the @dfn{ignore | |
4278 | count} of the breakpoint. Every breakpoint has an ignore count, which | |
4279 | is an integer. Most of the time, the ignore count is zero, and | |
4280 | therefore has no effect. But if your program reaches a breakpoint whose | |
4281 | ignore count is positive, then instead of stopping, it just decrements | |
4282 | the ignore count by one and continues. As a result, if the ignore count | |
4283 | value is @var{n}, the breakpoint does not stop the next @var{n} times | |
4284 | your program reaches it. | |
4285 | ||
4286 | @table @code | |
4287 | @kindex ignore | |
4288 | @item ignore @var{bnum} @var{count} | |
4289 | Set the ignore count of breakpoint number @var{bnum} to @var{count}. | |
4290 | The next @var{count} times the breakpoint is reached, your program's | |
4291 | execution does not stop; other than to decrement the ignore count, @value{GDBN} | |
4292 | takes no action. | |
4293 | ||
4294 | To make the breakpoint stop the next time it is reached, specify | |
4295 | a count of zero. | |
4296 | ||
4297 | When you use @code{continue} to resume execution of your program from a | |
4298 | breakpoint, you can specify an ignore count directly as an argument to | |
4299 | @code{continue}, rather than using @code{ignore}. @xref{Continuing and | |
79a6e687 | 4300 | Stepping,,Continuing and Stepping}. |
c906108c SS |
4301 | |
4302 | If a breakpoint has a positive ignore count and a condition, the | |
4303 | condition is not checked. Once the ignore count reaches zero, | |
4304 | @value{GDBN} resumes checking the condition. | |
4305 | ||
4306 | You could achieve the effect of the ignore count with a condition such | |
4307 | as @w{@samp{$foo-- <= 0}} using a debugger convenience variable that | |
4308 | is decremented each time. @xref{Convenience Vars, ,Convenience | |
79a6e687 | 4309 | Variables}. |
c906108c SS |
4310 | @end table |
4311 | ||
4312 | Ignore counts apply to breakpoints, watchpoints, and catchpoints. | |
4313 | ||
4314 | ||
6d2ebf8b | 4315 | @node Break Commands |
79a6e687 | 4316 | @subsection Breakpoint Command Lists |
c906108c SS |
4317 | |
4318 | @cindex breakpoint commands | |
4319 | You can give any breakpoint (or watchpoint or catchpoint) a series of | |
4320 | commands to execute when your program stops due to that breakpoint. For | |
4321 | example, you might want to print the values of certain expressions, or | |
4322 | enable other breakpoints. | |
4323 | ||
4324 | @table @code | |
4325 | @kindex commands | |
ca91424e | 4326 | @kindex end@r{ (breakpoint commands)} |
c906108c SS |
4327 | @item commands @r{[}@var{bnum}@r{]} |
4328 | @itemx @dots{} @var{command-list} @dots{} | |
4329 | @itemx end | |
4330 | Specify a list of commands for breakpoint number @var{bnum}. The commands | |
4331 | themselves appear on the following lines. Type a line containing just | |
4332 | @code{end} to terminate the commands. | |
4333 | ||
4334 | To remove all commands from a breakpoint, type @code{commands} and | |
4335 | follow it immediately with @code{end}; that is, give no commands. | |
4336 | ||
4337 | With no @var{bnum} argument, @code{commands} refers to the last | |
4338 | breakpoint, watchpoint, or catchpoint set (not to the breakpoint most | |
4339 | recently encountered). | |
4340 | @end table | |
4341 | ||
4342 | Pressing @key{RET} as a means of repeating the last @value{GDBN} command is | |
4343 | disabled within a @var{command-list}. | |
4344 | ||
4345 | You can use breakpoint commands to start your program up again. Simply | |
4346 | use the @code{continue} command, or @code{step}, or any other command | |
4347 | that resumes execution. | |
4348 | ||
4349 | Any other commands in the command list, after a command that resumes | |
4350 | execution, are ignored. This is because any time you resume execution | |
4351 | (even with a simple @code{next} or @code{step}), you may encounter | |
4352 | another breakpoint---which could have its own command list, leading to | |
4353 | ambiguities about which list to execute. | |
4354 | ||
4355 | @kindex silent | |
4356 | If the first command you specify in a command list is @code{silent}, the | |
4357 | usual message about stopping at a breakpoint is not printed. This may | |
4358 | be desirable for breakpoints that are to print a specific message and | |
4359 | then continue. If none of the remaining commands print anything, you | |
4360 | see no sign that the breakpoint was reached. @code{silent} is | |
4361 | meaningful only at the beginning of a breakpoint command list. | |
4362 | ||
4363 | The commands @code{echo}, @code{output}, and @code{printf} allow you to | |
4364 | print precisely controlled output, and are often useful in silent | |
79a6e687 | 4365 | breakpoints. @xref{Output, ,Commands for Controlled Output}. |
c906108c SS |
4366 | |
4367 | For example, here is how you could use breakpoint commands to print the | |
4368 | value of @code{x} at entry to @code{foo} whenever @code{x} is positive. | |
4369 | ||
474c8240 | 4370 | @smallexample |
c906108c SS |
4371 | break foo if x>0 |
4372 | commands | |
4373 | silent | |
4374 | printf "x is %d\n",x | |
4375 | cont | |
4376 | end | |
474c8240 | 4377 | @end smallexample |
c906108c SS |
4378 | |
4379 | One application for breakpoint commands is to compensate for one bug so | |
4380 | you can test for another. Put a breakpoint just after the erroneous line | |
4381 | of code, give it a condition to detect the case in which something | |
4382 | erroneous has been done, and give it commands to assign correct values | |
4383 | to any variables that need them. End with the @code{continue} command | |
4384 | so that your program does not stop, and start with the @code{silent} | |
4385 | command so that no output is produced. Here is an example: | |
4386 | ||
474c8240 | 4387 | @smallexample |
c906108c SS |
4388 | break 403 |
4389 | commands | |
4390 | silent | |
4391 | set x = y + 4 | |
4392 | cont | |
4393 | end | |
474c8240 | 4394 | @end smallexample |
c906108c | 4395 | |
c906108c | 4396 | @c @ifclear BARETARGET |
6d2ebf8b | 4397 | @node Error in Breakpoints |
d4f3574e | 4398 | @subsection ``Cannot insert breakpoints'' |
c906108c | 4399 | |
fa3a767f PA |
4400 | If you request too many active hardware-assisted breakpoints and |
4401 | watchpoints, you will see this error message: | |
d4f3574e SS |
4402 | |
4403 | @c FIXME: the precise wording of this message may change; the relevant | |
4404 | @c source change is not committed yet (Sep 3, 1999). | |
4405 | @smallexample | |
4406 | Stopped; cannot insert breakpoints. | |
4407 | You may have requested too many hardware breakpoints and watchpoints. | |
4408 | @end smallexample | |
4409 | ||
4410 | @noindent | |
4411 | This message is printed when you attempt to resume the program, since | |
4412 | only then @value{GDBN} knows exactly how many hardware breakpoints and | |
4413 | watchpoints it needs to insert. | |
4414 | ||
4415 | When this message is printed, you need to disable or remove some of the | |
4416 | hardware-assisted breakpoints and watchpoints, and then continue. | |
4417 | ||
79a6e687 | 4418 | @node Breakpoint-related Warnings |
1485d690 KB |
4419 | @subsection ``Breakpoint address adjusted...'' |
4420 | @cindex breakpoint address adjusted | |
4421 | ||
4422 | Some processor architectures place constraints on the addresses at | |
4423 | which breakpoints may be placed. For architectures thus constrained, | |
4424 | @value{GDBN} will attempt to adjust the breakpoint's address to comply | |
4425 | with the constraints dictated by the architecture. | |
4426 | ||
4427 | One example of such an architecture is the Fujitsu FR-V. The FR-V is | |
4428 | a VLIW architecture in which a number of RISC-like instructions may be | |
4429 | bundled together for parallel execution. The FR-V architecture | |
4430 | constrains the location of a breakpoint instruction within such a | |
4431 | bundle to the instruction with the lowest address. @value{GDBN} | |
4432 | honors this constraint by adjusting a breakpoint's address to the | |
4433 | first in the bundle. | |
4434 | ||
4435 | It is not uncommon for optimized code to have bundles which contain | |
4436 | instructions from different source statements, thus it may happen that | |
4437 | a breakpoint's address will be adjusted from one source statement to | |
4438 | another. Since this adjustment may significantly alter @value{GDBN}'s | |
4439 | breakpoint related behavior from what the user expects, a warning is | |
4440 | printed when the breakpoint is first set and also when the breakpoint | |
4441 | is hit. | |
4442 | ||
4443 | A warning like the one below is printed when setting a breakpoint | |
4444 | that's been subject to address adjustment: | |
4445 | ||
4446 | @smallexample | |
4447 | warning: Breakpoint address adjusted from 0x00010414 to 0x00010410. | |
4448 | @end smallexample | |
4449 | ||
4450 | Such warnings are printed both for user settable and @value{GDBN}'s | |
4451 | internal breakpoints. If you see one of these warnings, you should | |
4452 | verify that a breakpoint set at the adjusted address will have the | |
4453 | desired affect. If not, the breakpoint in question may be removed and | |
b383017d | 4454 | other breakpoints may be set which will have the desired behavior. |
1485d690 KB |
4455 | E.g., it may be sufficient to place the breakpoint at a later |
4456 | instruction. A conditional breakpoint may also be useful in some | |
4457 | cases to prevent the breakpoint from triggering too often. | |
4458 | ||
4459 | @value{GDBN} will also issue a warning when stopping at one of these | |
4460 | adjusted breakpoints: | |
4461 | ||
4462 | @smallexample | |
4463 | warning: Breakpoint 1 address previously adjusted from 0x00010414 | |
4464 | to 0x00010410. | |
4465 | @end smallexample | |
4466 | ||
4467 | When this warning is encountered, it may be too late to take remedial | |
4468 | action except in cases where the breakpoint is hit earlier or more | |
4469 | frequently than expected. | |
d4f3574e | 4470 | |
6d2ebf8b | 4471 | @node Continuing and Stepping |
79a6e687 | 4472 | @section Continuing and Stepping |
c906108c SS |
4473 | |
4474 | @cindex stepping | |
4475 | @cindex continuing | |
4476 | @cindex resuming execution | |
4477 | @dfn{Continuing} means resuming program execution until your program | |
4478 | completes normally. In contrast, @dfn{stepping} means executing just | |
4479 | one more ``step'' of your program, where ``step'' may mean either one | |
4480 | line of source code, or one machine instruction (depending on what | |
7a292a7a SS |
4481 | particular command you use). Either when continuing or when stepping, |
4482 | your program may stop even sooner, due to a breakpoint or a signal. (If | |
d4f3574e SS |
4483 | it stops due to a signal, you may want to use @code{handle}, or use |
4484 | @samp{signal 0} to resume execution. @xref{Signals, ,Signals}.) | |
c906108c SS |
4485 | |
4486 | @table @code | |
4487 | @kindex continue | |
41afff9a EZ |
4488 | @kindex c @r{(@code{continue})} |
4489 | @kindex fg @r{(resume foreground execution)} | |
c906108c SS |
4490 | @item continue @r{[}@var{ignore-count}@r{]} |
4491 | @itemx c @r{[}@var{ignore-count}@r{]} | |
4492 | @itemx fg @r{[}@var{ignore-count}@r{]} | |
4493 | Resume program execution, at the address where your program last stopped; | |
4494 | any breakpoints set at that address are bypassed. The optional argument | |
4495 | @var{ignore-count} allows you to specify a further number of times to | |
4496 | ignore a breakpoint at this location; its effect is like that of | |
79a6e687 | 4497 | @code{ignore} (@pxref{Conditions, ,Break Conditions}). |
c906108c SS |
4498 | |
4499 | The argument @var{ignore-count} is meaningful only when your program | |
4500 | stopped due to a breakpoint. At other times, the argument to | |
4501 | @code{continue} is ignored. | |
4502 | ||
d4f3574e SS |
4503 | The synonyms @code{c} and @code{fg} (for @dfn{foreground}, as the |
4504 | debugged program is deemed to be the foreground program) are provided | |
4505 | purely for convenience, and have exactly the same behavior as | |
4506 | @code{continue}. | |
c906108c SS |
4507 | @end table |
4508 | ||
4509 | To resume execution at a different place, you can use @code{return} | |
79a6e687 | 4510 | (@pxref{Returning, ,Returning from a Function}) to go back to the |
c906108c | 4511 | calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a |
79a6e687 | 4512 | Different Address}) to go to an arbitrary location in your program. |
c906108c SS |
4513 | |
4514 | A typical technique for using stepping is to set a breakpoint | |
79a6e687 | 4515 | (@pxref{Breakpoints, ,Breakpoints; Watchpoints; and Catchpoints}) at the |
c906108c SS |
4516 | beginning of the function or the section of your program where a problem |
4517 | is believed to lie, run your program until it stops at that breakpoint, | |
4518 | and then step through the suspect area, examining the variables that are | |
4519 | interesting, until you see the problem happen. | |
4520 | ||
4521 | @table @code | |
4522 | @kindex step | |
41afff9a | 4523 | @kindex s @r{(@code{step})} |
c906108c SS |
4524 | @item step |
4525 | Continue running your program until control reaches a different source | |
4526 | line, then stop it and return control to @value{GDBN}. This command is | |
4527 | abbreviated @code{s}. | |
4528 | ||
4529 | @quotation | |
4530 | @c "without debugging information" is imprecise; actually "without line | |
4531 | @c numbers in the debugging information". (gcc -g1 has debugging info but | |
4532 | @c not line numbers). But it seems complex to try to make that | |
4533 | @c distinction here. | |
4534 | @emph{Warning:} If you use the @code{step} command while control is | |
4535 | within a function that was compiled without debugging information, | |
4536 | execution proceeds until control reaches a function that does have | |
4537 | debugging information. Likewise, it will not step into a function which | |
4538 | is compiled without debugging information. To step through functions | |
4539 | without debugging information, use the @code{stepi} command, described | |
4540 | below. | |
4541 | @end quotation | |
4542 | ||
4a92d011 EZ |
4543 | The @code{step} command only stops at the first instruction of a source |
4544 | line. This prevents the multiple stops that could otherwise occur in | |
4545 | @code{switch} statements, @code{for} loops, etc. @code{step} continues | |
4546 | to stop if a function that has debugging information is called within | |
4547 | the line. In other words, @code{step} @emph{steps inside} any functions | |
4548 | called within the line. | |
c906108c | 4549 | |
d4f3574e SS |
4550 | Also, the @code{step} command only enters a function if there is line |
4551 | number information for the function. Otherwise it acts like the | |
5d161b24 | 4552 | @code{next} command. This avoids problems when using @code{cc -gl} |
c906108c | 4553 | on MIPS machines. Previously, @code{step} entered subroutines if there |
5d161b24 | 4554 | was any debugging information about the routine. |
c906108c SS |
4555 | |
4556 | @item step @var{count} | |
4557 | Continue running as in @code{step}, but do so @var{count} times. If a | |
7a292a7a SS |
4558 | breakpoint is reached, or a signal not related to stepping occurs before |
4559 | @var{count} steps, stepping stops right away. | |
c906108c SS |
4560 | |
4561 | @kindex next | |
41afff9a | 4562 | @kindex n @r{(@code{next})} |
c906108c SS |
4563 | @item next @r{[}@var{count}@r{]} |
4564 | Continue to the next source line in the current (innermost) stack frame. | |
7a292a7a SS |
4565 | This is similar to @code{step}, but function calls that appear within |
4566 | the line of code are executed without stopping. Execution stops when | |
4567 | control reaches a different line of code at the original stack level | |
4568 | that was executing when you gave the @code{next} command. This command | |
4569 | is abbreviated @code{n}. | |
c906108c SS |
4570 | |
4571 | An argument @var{count} is a repeat count, as for @code{step}. | |
4572 | ||
4573 | ||
4574 | @c FIX ME!! Do we delete this, or is there a way it fits in with | |
4575 | @c the following paragraph? --- Vctoria | |
4576 | @c | |
4577 | @c @code{next} within a function that lacks debugging information acts like | |
4578 | @c @code{step}, but any function calls appearing within the code of the | |
4579 | @c function are executed without stopping. | |
4580 | ||
d4f3574e SS |
4581 | The @code{next} command only stops at the first instruction of a |
4582 | source line. This prevents multiple stops that could otherwise occur in | |
4a92d011 | 4583 | @code{switch} statements, @code{for} loops, etc. |
c906108c | 4584 | |
b90a5f51 CF |
4585 | @kindex set step-mode |
4586 | @item set step-mode | |
4587 | @cindex functions without line info, and stepping | |
4588 | @cindex stepping into functions with no line info | |
4589 | @itemx set step-mode on | |
4a92d011 | 4590 | The @code{set step-mode on} command causes the @code{step} command to |
b90a5f51 CF |
4591 | stop at the first instruction of a function which contains no debug line |
4592 | information rather than stepping over it. | |
4593 | ||
4a92d011 EZ |
4594 | This is useful in cases where you may be interested in inspecting the |
4595 | machine instructions of a function which has no symbolic info and do not | |
4596 | want @value{GDBN} to automatically skip over this function. | |
b90a5f51 CF |
4597 | |
4598 | @item set step-mode off | |
4a92d011 | 4599 | Causes the @code{step} command to step over any functions which contains no |
b90a5f51 CF |
4600 | debug information. This is the default. |
4601 | ||
9c16f35a EZ |
4602 | @item show step-mode |
4603 | Show whether @value{GDBN} will stop in or step over functions without | |
4604 | source line debug information. | |
4605 | ||
c906108c | 4606 | @kindex finish |
8dfa32fc | 4607 | @kindex fin @r{(@code{finish})} |
c906108c SS |
4608 | @item finish |
4609 | Continue running until just after function in the selected stack frame | |
8dfa32fc JB |
4610 | returns. Print the returned value (if any). This command can be |
4611 | abbreviated as @code{fin}. | |
c906108c SS |
4612 | |
4613 | Contrast this with the @code{return} command (@pxref{Returning, | |
79a6e687 | 4614 | ,Returning from a Function}). |
c906108c SS |
4615 | |
4616 | @kindex until | |
41afff9a | 4617 | @kindex u @r{(@code{until})} |
09d4efe1 | 4618 | @cindex run until specified location |
c906108c SS |
4619 | @item until |
4620 | @itemx u | |
4621 | Continue running until a source line past the current line, in the | |
4622 | current stack frame, is reached. This command is used to avoid single | |
4623 | stepping through a loop more than once. It is like the @code{next} | |
4624 | command, except that when @code{until} encounters a jump, it | |
4625 | automatically continues execution until the program counter is greater | |
4626 | than the address of the jump. | |
4627 | ||
4628 | This means that when you reach the end of a loop after single stepping | |
4629 | though it, @code{until} makes your program continue execution until it | |
4630 | exits the loop. In contrast, a @code{next} command at the end of a loop | |
4631 | simply steps back to the beginning of the loop, which forces you to step | |
4632 | through the next iteration. | |
4633 | ||
4634 | @code{until} always stops your program if it attempts to exit the current | |
4635 | stack frame. | |
4636 | ||
4637 | @code{until} may produce somewhat counterintuitive results if the order | |
4638 | of machine code does not match the order of the source lines. For | |
4639 | example, in the following excerpt from a debugging session, the @code{f} | |
4640 | (@code{frame}) command shows that execution is stopped at line | |
4641 | @code{206}; yet when we use @code{until}, we get to line @code{195}: | |
4642 | ||
474c8240 | 4643 | @smallexample |
c906108c SS |
4644 | (@value{GDBP}) f |
4645 | #0 main (argc=4, argv=0xf7fffae8) at m4.c:206 | |
4646 | 206 expand_input(); | |
4647 | (@value{GDBP}) until | |
4648 | 195 for ( ; argc > 0; NEXTARG) @{ | |
474c8240 | 4649 | @end smallexample |
c906108c SS |
4650 | |
4651 | This happened because, for execution efficiency, the compiler had | |
4652 | generated code for the loop closure test at the end, rather than the | |
4653 | start, of the loop---even though the test in a C @code{for}-loop is | |
4654 | written before the body of the loop. The @code{until} command appeared | |
4655 | to step back to the beginning of the loop when it advanced to this | |
4656 | expression; however, it has not really gone to an earlier | |
4657 | statement---not in terms of the actual machine code. | |
4658 | ||
4659 | @code{until} with no argument works by means of single | |
4660 | instruction stepping, and hence is slower than @code{until} with an | |
4661 | argument. | |
4662 | ||
4663 | @item until @var{location} | |
4664 | @itemx u @var{location} | |
4665 | Continue running your program until either the specified location is | |
4666 | reached, or the current stack frame returns. @var{location} is any of | |
2a25a5ba EZ |
4667 | the forms described in @ref{Specify Location}. |
4668 | This form of the command uses temporary breakpoints, and | |
c60eb6f1 EZ |
4669 | hence is quicker than @code{until} without an argument. The specified |
4670 | location is actually reached only if it is in the current frame. This | |
4671 | implies that @code{until} can be used to skip over recursive function | |
4672 | invocations. For instance in the code below, if the current location is | |
4673 | line @code{96}, issuing @code{until 99} will execute the program up to | |
db2e3e2e | 4674 | line @code{99} in the same invocation of factorial, i.e., after the inner |
c60eb6f1 EZ |
4675 | invocations have returned. |
4676 | ||
4677 | @smallexample | |
4678 | 94 int factorial (int value) | |
4679 | 95 @{ | |
4680 | 96 if (value > 1) @{ | |
4681 | 97 value *= factorial (value - 1); | |
4682 | 98 @} | |
4683 | 99 return (value); | |
4684 | 100 @} | |
4685 | @end smallexample | |
4686 | ||
4687 | ||
4688 | @kindex advance @var{location} | |
4689 | @itemx advance @var{location} | |
09d4efe1 | 4690 | Continue running the program up to the given @var{location}. An argument is |
2a25a5ba EZ |
4691 | required, which should be of one of the forms described in |
4692 | @ref{Specify Location}. | |
4693 | Execution will also stop upon exit from the current stack | |
c60eb6f1 EZ |
4694 | frame. This command is similar to @code{until}, but @code{advance} will |
4695 | not skip over recursive function calls, and the target location doesn't | |
4696 | have to be in the same frame as the current one. | |
4697 | ||
c906108c SS |
4698 | |
4699 | @kindex stepi | |
41afff9a | 4700 | @kindex si @r{(@code{stepi})} |
c906108c | 4701 | @item stepi |
96a2c332 | 4702 | @itemx stepi @var{arg} |
c906108c SS |
4703 | @itemx si |
4704 | Execute one machine instruction, then stop and return to the debugger. | |
4705 | ||
4706 | It is often useful to do @samp{display/i $pc} when stepping by machine | |
4707 | instructions. This makes @value{GDBN} automatically display the next | |
4708 | instruction to be executed, each time your program stops. @xref{Auto | |
79a6e687 | 4709 | Display,, Automatic Display}. |
c906108c SS |
4710 | |
4711 | An argument is a repeat count, as in @code{step}. | |
4712 | ||
4713 | @need 750 | |
4714 | @kindex nexti | |
41afff9a | 4715 | @kindex ni @r{(@code{nexti})} |
c906108c | 4716 | @item nexti |
96a2c332 | 4717 | @itemx nexti @var{arg} |
c906108c SS |
4718 | @itemx ni |
4719 | Execute one machine instruction, but if it is a function call, | |
4720 | proceed until the function returns. | |
4721 | ||
4722 | An argument is a repeat count, as in @code{next}. | |
4723 | @end table | |
4724 | ||
6d2ebf8b | 4725 | @node Signals |
c906108c SS |
4726 | @section Signals |
4727 | @cindex signals | |
4728 | ||
4729 | A signal is an asynchronous event that can happen in a program. The | |
4730 | operating system defines the possible kinds of signals, and gives each | |
4731 | kind a name and a number. For example, in Unix @code{SIGINT} is the | |
c8aa23ab | 4732 | signal a program gets when you type an interrupt character (often @kbd{Ctrl-c}); |
c906108c SS |
4733 | @code{SIGSEGV} is the signal a program gets from referencing a place in |
4734 | memory far away from all the areas in use; @code{SIGALRM} occurs when | |
4735 | the alarm clock timer goes off (which happens only if your program has | |
4736 | requested an alarm). | |
4737 | ||
4738 | @cindex fatal signals | |
4739 | Some signals, including @code{SIGALRM}, are a normal part of the | |
4740 | functioning of your program. Others, such as @code{SIGSEGV}, indicate | |
d4f3574e | 4741 | errors; these signals are @dfn{fatal} (they kill your program immediately) if the |
c906108c SS |
4742 | program has not specified in advance some other way to handle the signal. |
4743 | @code{SIGINT} does not indicate an error in your program, but it is normally | |
4744 | fatal so it can carry out the purpose of the interrupt: to kill the program. | |
4745 | ||
4746 | @value{GDBN} has the ability to detect any occurrence of a signal in your | |
4747 | program. You can tell @value{GDBN} in advance what to do for each kind of | |
4748 | signal. | |
4749 | ||
4750 | @cindex handling signals | |
24f93129 EZ |
4751 | Normally, @value{GDBN} is set up to let the non-erroneous signals like |
4752 | @code{SIGALRM} be silently passed to your program | |
4753 | (so as not to interfere with their role in the program's functioning) | |
c906108c SS |
4754 | but to stop your program immediately whenever an error signal happens. |
4755 | You can change these settings with the @code{handle} command. | |
4756 | ||
4757 | @table @code | |
4758 | @kindex info signals | |
09d4efe1 | 4759 | @kindex info handle |
c906108c | 4760 | @item info signals |
96a2c332 | 4761 | @itemx info handle |
c906108c SS |
4762 | Print a table of all the kinds of signals and how @value{GDBN} has been told to |
4763 | handle each one. You can use this to see the signal numbers of all | |
4764 | the defined types of signals. | |
4765 | ||
45ac1734 EZ |
4766 | @item info signals @var{sig} |
4767 | Similar, but print information only about the specified signal number. | |
4768 | ||
d4f3574e | 4769 | @code{info handle} is an alias for @code{info signals}. |
c906108c SS |
4770 | |
4771 | @kindex handle | |
45ac1734 | 4772 | @item handle @var{signal} @r{[}@var{keywords}@dots{}@r{]} |
5ece1a18 EZ |
4773 | Change the way @value{GDBN} handles signal @var{signal}. @var{signal} |
4774 | can be the number of a signal or its name (with or without the | |
24f93129 | 4775 | @samp{SIG} at the beginning); a list of signal numbers of the form |
5ece1a18 | 4776 | @samp{@var{low}-@var{high}}; or the word @samp{all}, meaning all the |
45ac1734 EZ |
4777 | known signals. Optional arguments @var{keywords}, described below, |
4778 | say what change to make. | |
c906108c SS |
4779 | @end table |
4780 | ||
4781 | @c @group | |
4782 | The keywords allowed by the @code{handle} command can be abbreviated. | |
4783 | Their full names are: | |
4784 | ||
4785 | @table @code | |
4786 | @item nostop | |
4787 | @value{GDBN} should not stop your program when this signal happens. It may | |
4788 | still print a message telling you that the signal has come in. | |
4789 | ||
4790 | @item stop | |
4791 | @value{GDBN} should stop your program when this signal happens. This implies | |
4792 | the @code{print} keyword as well. | |
4793 | ||
4794 | @item print | |
4795 | @value{GDBN} should print a message when this signal happens. | |
4796 | ||
4797 | @item noprint | |
4798 | @value{GDBN} should not mention the occurrence of the signal at all. This | |
4799 | implies the @code{nostop} keyword as well. | |
4800 | ||
4801 | @item pass | |
5ece1a18 | 4802 | @itemx noignore |
c906108c SS |
4803 | @value{GDBN} should allow your program to see this signal; your program |
4804 | can handle the signal, or else it may terminate if the signal is fatal | |
5ece1a18 | 4805 | and not handled. @code{pass} and @code{noignore} are synonyms. |
c906108c SS |
4806 | |
4807 | @item nopass | |
5ece1a18 | 4808 | @itemx ignore |
c906108c | 4809 | @value{GDBN} should not allow your program to see this signal. |
5ece1a18 | 4810 | @code{nopass} and @code{ignore} are synonyms. |
c906108c SS |
4811 | @end table |
4812 | @c @end group | |
4813 | ||
d4f3574e SS |
4814 | When a signal stops your program, the signal is not visible to the |
4815 | program until you | |
c906108c SS |
4816 | continue. Your program sees the signal then, if @code{pass} is in |
4817 | effect for the signal in question @emph{at that time}. In other words, | |
4818 | after @value{GDBN} reports a signal, you can use the @code{handle} | |
4819 | command with @code{pass} or @code{nopass} to control whether your | |
4820 | program sees that signal when you continue. | |
4821 | ||
24f93129 EZ |
4822 | The default is set to @code{nostop}, @code{noprint}, @code{pass} for |
4823 | non-erroneous signals such as @code{SIGALRM}, @code{SIGWINCH} and | |
4824 | @code{SIGCHLD}, and to @code{stop}, @code{print}, @code{pass} for the | |
4825 | erroneous signals. | |
4826 | ||
c906108c SS |
4827 | You can also use the @code{signal} command to prevent your program from |
4828 | seeing a signal, or cause it to see a signal it normally would not see, | |
4829 | or to give it any signal at any time. For example, if your program stopped | |
4830 | due to some sort of memory reference error, you might store correct | |
4831 | values into the erroneous variables and continue, hoping to see more | |
4832 | execution; but your program would probably terminate immediately as | |
4833 | a result of the fatal signal once it saw the signal. To prevent this, | |
4834 | you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your | |
79a6e687 | 4835 | Program a Signal}. |
c906108c | 4836 | |
4aa995e1 PA |
4837 | @cindex extra signal information |
4838 | @anchor{extra signal information} | |
4839 | ||
4840 | On some targets, @value{GDBN} can inspect extra signal information | |
4841 | associated with the intercepted signal, before it is actually | |
4842 | delivered to the program being debugged. This information is exported | |
4843 | by the convenience variable @code{$_siginfo}, and consists of data | |
4844 | that is passed by the kernel to the signal handler at the time of the | |
4845 | receipt of a signal. The data type of the information itself is | |
4846 | target dependent. You can see the data type using the @code{ptype | |
4847 | $_siginfo} command. On Unix systems, it typically corresponds to the | |
4848 | standard @code{siginfo_t} type, as defined in the @file{signal.h} | |
4849 | system header. | |
4850 | ||
4851 | Here's an example, on a @sc{gnu}/Linux system, printing the stray | |
4852 | referenced address that raised a segmentation fault. | |
4853 | ||
4854 | @smallexample | |
4855 | @group | |
4856 | (@value{GDBP}) continue | |
4857 | Program received signal SIGSEGV, Segmentation fault. | |
4858 | 0x0000000000400766 in main () | |
4859 | 69 *(int *)p = 0; | |
4860 | (@value{GDBP}) ptype $_siginfo | |
4861 | type = struct @{ | |
4862 | int si_signo; | |
4863 | int si_errno; | |
4864 | int si_code; | |
4865 | union @{ | |
4866 | int _pad[28]; | |
4867 | struct @{...@} _kill; | |
4868 | struct @{...@} _timer; | |
4869 | struct @{...@} _rt; | |
4870 | struct @{...@} _sigchld; | |
4871 | struct @{...@} _sigfault; | |
4872 | struct @{...@} _sigpoll; | |
4873 | @} _sifields; | |
4874 | @} | |
4875 | (@value{GDBP}) ptype $_siginfo._sifields._sigfault | |
4876 | type = struct @{ | |
4877 | void *si_addr; | |
4878 | @} | |
4879 | (@value{GDBP}) p $_siginfo._sifields._sigfault.si_addr | |
4880 | $1 = (void *) 0x7ffff7ff7000 | |
4881 | @end group | |
4882 | @end smallexample | |
4883 | ||
4884 | Depending on target support, @code{$_siginfo} may also be writable. | |
4885 | ||
6d2ebf8b | 4886 | @node Thread Stops |
79a6e687 | 4887 | @section Stopping and Starting Multi-thread Programs |
c906108c | 4888 | |
0606b73b SL |
4889 | @cindex stopped threads |
4890 | @cindex threads, stopped | |
4891 | ||
4892 | @cindex continuing threads | |
4893 | @cindex threads, continuing | |
4894 | ||
4895 | @value{GDBN} supports debugging programs with multiple threads | |
4896 | (@pxref{Threads,, Debugging Programs with Multiple Threads}). There | |
4897 | are two modes of controlling execution of your program within the | |
4898 | debugger. In the default mode, referred to as @dfn{all-stop mode}, | |
4899 | when any thread in your program stops (for example, at a breakpoint | |
4900 | or while being stepped), all other threads in the program are also stopped by | |
4901 | @value{GDBN}. On some targets, @value{GDBN} also supports | |
4902 | @dfn{non-stop mode}, in which other threads can continue to run freely while | |
4903 | you examine the stopped thread in the debugger. | |
4904 | ||
4905 | @menu | |
4906 | * All-Stop Mode:: All threads stop when GDB takes control | |
4907 | * Non-Stop Mode:: Other threads continue to execute | |
4908 | * Background Execution:: Running your program asynchronously | |
4909 | * Thread-Specific Breakpoints:: Controlling breakpoints | |
4910 | * Interrupted System Calls:: GDB may interfere with system calls | |
4911 | @end menu | |
4912 | ||
4913 | @node All-Stop Mode | |
4914 | @subsection All-Stop Mode | |
4915 | ||
4916 | @cindex all-stop mode | |
4917 | ||
4918 | In all-stop mode, whenever your program stops under @value{GDBN} for any reason, | |
4919 | @emph{all} threads of execution stop, not just the current thread. This | |
4920 | allows you to examine the overall state of the program, including | |
4921 | switching between threads, without worrying that things may change | |
4922 | underfoot. | |
4923 | ||
4924 | Conversely, whenever you restart the program, @emph{all} threads start | |
4925 | executing. @emph{This is true even when single-stepping} with commands | |
4926 | like @code{step} or @code{next}. | |
4927 | ||
4928 | In particular, @value{GDBN} cannot single-step all threads in lockstep. | |
4929 | Since thread scheduling is up to your debugging target's operating | |
4930 | system (not controlled by @value{GDBN}), other threads may | |
4931 | execute more than one statement while the current thread completes a | |
4932 | single step. Moreover, in general other threads stop in the middle of a | |
4933 | statement, rather than at a clean statement boundary, when the program | |
4934 | stops. | |
4935 | ||
4936 | You might even find your program stopped in another thread after | |
4937 | continuing or even single-stepping. This happens whenever some other | |
4938 | thread runs into a breakpoint, a signal, or an exception before the | |
4939 | first thread completes whatever you requested. | |
4940 | ||
4941 | @cindex automatic thread selection | |
4942 | @cindex switching threads automatically | |
4943 | @cindex threads, automatic switching | |
4944 | Whenever @value{GDBN} stops your program, due to a breakpoint or a | |
4945 | signal, it automatically selects the thread where that breakpoint or | |
4946 | signal happened. @value{GDBN} alerts you to the context switch with a | |
4947 | message such as @samp{[Switching to Thread @var{n}]} to identify the | |
4948 | thread. | |
4949 | ||
4950 | On some OSes, you can modify @value{GDBN}'s default behavior by | |
4951 | locking the OS scheduler to allow only a single thread to run. | |
4952 | ||
4953 | @table @code | |
4954 | @item set scheduler-locking @var{mode} | |
4955 | @cindex scheduler locking mode | |
4956 | @cindex lock scheduler | |
4957 | Set the scheduler locking mode. If it is @code{off}, then there is no | |
4958 | locking and any thread may run at any time. If @code{on}, then only the | |
4959 | current thread may run when the inferior is resumed. The @code{step} | |
4960 | mode optimizes for single-stepping; it prevents other threads | |
4961 | from preempting the current thread while you are stepping, so that | |
4962 | the focus of debugging does not change unexpectedly. | |
4963 | Other threads only rarely (or never) get a chance to run | |
4964 | when you step. They are more likely to run when you @samp{next} over a | |
4965 | function call, and they are completely free to run when you use commands | |
4966 | like @samp{continue}, @samp{until}, or @samp{finish}. However, unless another | |
4967 | thread hits a breakpoint during its timeslice, @value{GDBN} does not change | |
4968 | the current thread away from the thread that you are debugging. | |
4969 | ||
4970 | @item show scheduler-locking | |
4971 | Display the current scheduler locking mode. | |
4972 | @end table | |
4973 | ||
d4db2f36 PA |
4974 | @cindex resume threads of multiple processes simultaneously |
4975 | By default, when you issue one of the execution commands such as | |
4976 | @code{continue}, @code{next} or @code{step}, @value{GDBN} allows only | |
4977 | threads of the current inferior to run. For example, if @value{GDBN} | |
4978 | is attached to two inferiors, each with two threads, the | |
4979 | @code{continue} command resumes only the two threads of the current | |
4980 | inferior. This is useful, for example, when you debug a program that | |
4981 | forks and you want to hold the parent stopped (so that, for instance, | |
4982 | it doesn't run to exit), while you debug the child. In other | |
4983 | situations, you may not be interested in inspecting the current state | |
4984 | of any of the processes @value{GDBN} is attached to, and you may want | |
4985 | to resume them all until some breakpoint is hit. In the latter case, | |
4986 | you can instruct @value{GDBN} to allow all threads of all the | |
4987 | inferiors to run with the @w{@code{set schedule-multiple}} command. | |
4988 | ||
4989 | @table @code | |
4990 | @kindex set schedule-multiple | |
4991 | @item set schedule-multiple | |
4992 | Set the mode for allowing threads of multiple processes to be resumed | |
4993 | when an execution command is issued. When @code{on}, all threads of | |
4994 | all processes are allowed to run. When @code{off}, only the threads | |
4995 | of the current process are resumed. The default is @code{off}. The | |
4996 | @code{scheduler-locking} mode takes precedence when set to @code{on}, | |
4997 | or while you are stepping and set to @code{step}. | |
4998 | ||
4999 | @item show schedule-multiple | |
5000 | Display the current mode for resuming the execution of threads of | |
5001 | multiple processes. | |
5002 | @end table | |
5003 | ||
0606b73b SL |
5004 | @node Non-Stop Mode |
5005 | @subsection Non-Stop Mode | |
5006 | ||
5007 | @cindex non-stop mode | |
5008 | ||
5009 | @c This section is really only a place-holder, and needs to be expanded | |
5010 | @c with more details. | |
5011 | ||
5012 | For some multi-threaded targets, @value{GDBN} supports an optional | |
5013 | mode of operation in which you can examine stopped program threads in | |
5014 | the debugger while other threads continue to execute freely. This | |
5015 | minimizes intrusion when debugging live systems, such as programs | |
5016 | where some threads have real-time constraints or must continue to | |
5017 | respond to external events. This is referred to as @dfn{non-stop} mode. | |
5018 | ||
5019 | In non-stop mode, when a thread stops to report a debugging event, | |
5020 | @emph{only} that thread is stopped; @value{GDBN} does not stop other | |
5021 | threads as well, in contrast to the all-stop mode behavior. Additionally, | |
5022 | execution commands such as @code{continue} and @code{step} apply by default | |
5023 | only to the current thread in non-stop mode, rather than all threads as | |
5024 | in all-stop mode. This allows you to control threads explicitly in | |
5025 | ways that are not possible in all-stop mode --- for example, stepping | |
5026 | one thread while allowing others to run freely, stepping | |
5027 | one thread while holding all others stopped, or stepping several threads | |
5028 | independently and simultaneously. | |
5029 | ||
5030 | To enter non-stop mode, use this sequence of commands before you run | |
5031 | or attach to your program: | |
5032 | ||
0606b73b SL |
5033 | @smallexample |
5034 | # Enable the async interface. | |
c6ebd6cf | 5035 | set target-async 1 |
0606b73b | 5036 | |
0606b73b SL |
5037 | # If using the CLI, pagination breaks non-stop. |
5038 | set pagination off | |
5039 | ||
5040 | # Finally, turn it on! | |
5041 | set non-stop on | |
5042 | @end smallexample | |
5043 | ||
5044 | You can use these commands to manipulate the non-stop mode setting: | |
5045 | ||
5046 | @table @code | |
5047 | @kindex set non-stop | |
5048 | @item set non-stop on | |
5049 | Enable selection of non-stop mode. | |
5050 | @item set non-stop off | |
5051 | Disable selection of non-stop mode. | |
5052 | @kindex show non-stop | |
5053 | @item show non-stop | |
5054 | Show the current non-stop enablement setting. | |
5055 | @end table | |
5056 | ||
5057 | Note these commands only reflect whether non-stop mode is enabled, | |
5058 | not whether the currently-executing program is being run in non-stop mode. | |
5059 | In particular, the @code{set non-stop} preference is only consulted when | |
5060 | @value{GDBN} starts or connects to the target program, and it is generally | |
5061 | not possible to switch modes once debugging has started. Furthermore, | |
5062 | since not all targets support non-stop mode, even when you have enabled | |
5063 | non-stop mode, @value{GDBN} may still fall back to all-stop operation by | |
5064 | default. | |
5065 | ||
5066 | In non-stop mode, all execution commands apply only to the current thread | |
5067 | by default. That is, @code{continue} only continues one thread. | |
5068 | To continue all threads, issue @code{continue -a} or @code{c -a}. | |
5069 | ||
5070 | You can use @value{GDBN}'s background execution commands | |
5071 | (@pxref{Background Execution}) to run some threads in the background | |
5072 | while you continue to examine or step others from @value{GDBN}. | |
5073 | The MI execution commands (@pxref{GDB/MI Program Execution}) are | |
5074 | always executed asynchronously in non-stop mode. | |
5075 | ||
5076 | Suspending execution is done with the @code{interrupt} command when | |
5077 | running in the background, or @kbd{Ctrl-c} during foreground execution. | |
5078 | In all-stop mode, this stops the whole process; | |
5079 | but in non-stop mode the interrupt applies only to the current thread. | |
5080 | To stop the whole program, use @code{interrupt -a}. | |
5081 | ||
5082 | Other execution commands do not currently support the @code{-a} option. | |
5083 | ||
5084 | In non-stop mode, when a thread stops, @value{GDBN} doesn't automatically make | |
5085 | that thread current, as it does in all-stop mode. This is because the | |
5086 | thread stop notifications are asynchronous with respect to @value{GDBN}'s | |
5087 | command interpreter, and it would be confusing if @value{GDBN} unexpectedly | |
5088 | changed to a different thread just as you entered a command to operate on the | |
5089 | previously current thread. | |
5090 | ||
5091 | @node Background Execution | |
5092 | @subsection Background Execution | |
5093 | ||
5094 | @cindex foreground execution | |
5095 | @cindex background execution | |
5096 | @cindex asynchronous execution | |
5097 | @cindex execution, foreground, background and asynchronous | |
5098 | ||
5099 | @value{GDBN}'s execution commands have two variants: the normal | |
5100 | foreground (synchronous) behavior, and a background | |
5101 | (asynchronous) behavior. In foreground execution, @value{GDBN} waits for | |
5102 | the program to report that some thread has stopped before prompting for | |
5103 | another command. In background execution, @value{GDBN} immediately gives | |
5104 | a command prompt so that you can issue other commands while your program runs. | |
5105 | ||
32fc0df9 PA |
5106 | You need to explicitly enable asynchronous mode before you can use |
5107 | background execution commands. You can use these commands to | |
5108 | manipulate the asynchronous mode setting: | |
5109 | ||
5110 | @table @code | |
5111 | @kindex set target-async | |
5112 | @item set target-async on | |
5113 | Enable asynchronous mode. | |
5114 | @item set target-async off | |
5115 | Disable asynchronous mode. | |
5116 | @kindex show target-async | |
5117 | @item show target-async | |
5118 | Show the current target-async setting. | |
5119 | @end table | |
5120 | ||
5121 | If the target doesn't support async mode, @value{GDBN} issues an error | |
5122 | message if you attempt to use the background execution commands. | |
5123 | ||
0606b73b SL |
5124 | To specify background execution, add a @code{&} to the command. For example, |
5125 | the background form of the @code{continue} command is @code{continue&}, or | |
5126 | just @code{c&}. The execution commands that accept background execution | |
5127 | are: | |
5128 | ||
5129 | @table @code | |
5130 | @kindex run& | |
5131 | @item run | |
5132 | @xref{Starting, , Starting your Program}. | |
5133 | ||
5134 | @item attach | |
5135 | @kindex attach& | |
5136 | @xref{Attach, , Debugging an Already-running Process}. | |
5137 | ||
5138 | @item step | |
5139 | @kindex step& | |
5140 | @xref{Continuing and Stepping, step}. | |
5141 | ||
5142 | @item stepi | |
5143 | @kindex stepi& | |
5144 | @xref{Continuing and Stepping, stepi}. | |
5145 | ||
5146 | @item next | |
5147 | @kindex next& | |
5148 | @xref{Continuing and Stepping, next}. | |
5149 | ||
7ce58dd2 DE |
5150 | @item nexti |
5151 | @kindex nexti& | |
5152 | @xref{Continuing and Stepping, nexti}. | |
5153 | ||
0606b73b SL |
5154 | @item continue |
5155 | @kindex continue& | |
5156 | @xref{Continuing and Stepping, continue}. | |
5157 | ||
5158 | @item finish | |
5159 | @kindex finish& | |
5160 | @xref{Continuing and Stepping, finish}. | |
5161 | ||
5162 | @item until | |
5163 | @kindex until& | |
5164 | @xref{Continuing and Stepping, until}. | |
5165 | ||
5166 | @end table | |
5167 | ||
5168 | Background execution is especially useful in conjunction with non-stop | |
5169 | mode for debugging programs with multiple threads; see @ref{Non-Stop Mode}. | |
5170 | However, you can also use these commands in the normal all-stop mode with | |
5171 | the restriction that you cannot issue another execution command until the | |
5172 | previous one finishes. Examples of commands that are valid in all-stop | |
5173 | mode while the program is running include @code{help} and @code{info break}. | |
5174 | ||
5175 | You can interrupt your program while it is running in the background by | |
5176 | using the @code{interrupt} command. | |
5177 | ||
5178 | @table @code | |
5179 | @kindex interrupt | |
5180 | @item interrupt | |
5181 | @itemx interrupt -a | |
5182 | ||
5183 | Suspend execution of the running program. In all-stop mode, | |
5184 | @code{interrupt} stops the whole process, but in non-stop mode, it stops | |
5185 | only the current thread. To stop the whole program in non-stop mode, | |
5186 | use @code{interrupt -a}. | |
5187 | @end table | |
5188 | ||
0606b73b SL |
5189 | @node Thread-Specific Breakpoints |
5190 | @subsection Thread-Specific Breakpoints | |
5191 | ||
c906108c | 5192 | When your program has multiple threads (@pxref{Threads,, Debugging |
79a6e687 | 5193 | Programs with Multiple Threads}), you can choose whether to set |
c906108c SS |
5194 | breakpoints on all threads, or on a particular thread. |
5195 | ||
5196 | @table @code | |
5197 | @cindex breakpoints and threads | |
5198 | @cindex thread breakpoints | |
5199 | @kindex break @dots{} thread @var{threadno} | |
5200 | @item break @var{linespec} thread @var{threadno} | |
5201 | @itemx break @var{linespec} thread @var{threadno} if @dots{} | |
5202 | @var{linespec} specifies source lines; there are several ways of | |
2a25a5ba EZ |
5203 | writing them (@pxref{Specify Location}), but the effect is always to |
5204 | specify some source line. | |
c906108c SS |
5205 | |
5206 | Use the qualifier @samp{thread @var{threadno}} with a breakpoint command | |
5207 | to specify that you only want @value{GDBN} to stop the program when a | |
5208 | particular thread reaches this breakpoint. @var{threadno} is one of the | |
5209 | numeric thread identifiers assigned by @value{GDBN}, shown in the first | |
5210 | column of the @samp{info threads} display. | |
5211 | ||
5212 | If you do not specify @samp{thread @var{threadno}} when you set a | |
5213 | breakpoint, the breakpoint applies to @emph{all} threads of your | |
5214 | program. | |
5215 | ||
5216 | You can use the @code{thread} qualifier on conditional breakpoints as | |
b6199126 DJ |
5217 | well; in this case, place @samp{thread @var{threadno}} before or |
5218 | after the breakpoint condition, like this: | |
c906108c SS |
5219 | |
5220 | @smallexample | |
2df3850c | 5221 | (@value{GDBP}) break frik.c:13 thread 28 if bartab > lim |
c906108c SS |
5222 | @end smallexample |
5223 | ||
5224 | @end table | |
5225 | ||
0606b73b SL |
5226 | @node Interrupted System Calls |
5227 | @subsection Interrupted System Calls | |
c906108c | 5228 | |
36d86913 MC |
5229 | @cindex thread breakpoints and system calls |
5230 | @cindex system calls and thread breakpoints | |
5231 | @cindex premature return from system calls | |
0606b73b SL |
5232 | There is an unfortunate side effect when using @value{GDBN} to debug |
5233 | multi-threaded programs. If one thread stops for a | |
36d86913 MC |
5234 | breakpoint, or for some other reason, and another thread is blocked in a |
5235 | system call, then the system call may return prematurely. This is a | |
5236 | consequence of the interaction between multiple threads and the signals | |
5237 | that @value{GDBN} uses to implement breakpoints and other events that | |
5238 | stop execution. | |
5239 | ||
5240 | To handle this problem, your program should check the return value of | |
5241 | each system call and react appropriately. This is good programming | |
5242 | style anyways. | |
5243 | ||
5244 | For example, do not write code like this: | |
5245 | ||
5246 | @smallexample | |
5247 | sleep (10); | |
5248 | @end smallexample | |
5249 | ||
5250 | The call to @code{sleep} will return early if a different thread stops | |
5251 | at a breakpoint or for some other reason. | |
5252 | ||
5253 | Instead, write this: | |
5254 | ||
5255 | @smallexample | |
5256 | int unslept = 10; | |
5257 | while (unslept > 0) | |
5258 | unslept = sleep (unslept); | |
5259 | @end smallexample | |
5260 | ||
5261 | A system call is allowed to return early, so the system is still | |
5262 | conforming to its specification. But @value{GDBN} does cause your | |
5263 | multi-threaded program to behave differently than it would without | |
5264 | @value{GDBN}. | |
5265 | ||
5266 | Also, @value{GDBN} uses internal breakpoints in the thread library to | |
5267 | monitor certain events such as thread creation and thread destruction. | |
5268 | When such an event happens, a system call in another thread may return | |
5269 | prematurely, even though your program does not appear to stop. | |
5270 | ||
c906108c | 5271 | |
bacec72f MS |
5272 | @node Reverse Execution |
5273 | @chapter Running programs backward | |
5274 | @cindex reverse execution | |
5275 | @cindex running programs backward | |
5276 | ||
5277 | When you are debugging a program, it is not unusual to realize that | |
5278 | you have gone too far, and some event of interest has already happened. | |
5279 | If the target environment supports it, @value{GDBN} can allow you to | |
5280 | ``rewind'' the program by running it backward. | |
5281 | ||
5282 | A target environment that supports reverse execution should be able | |
5283 | to ``undo'' the changes in machine state that have taken place as the | |
5284 | program was executing normally. Variables, registers etc.@: should | |
5285 | revert to their previous values. Obviously this requires a great | |
5286 | deal of sophistication on the part of the target environment; not | |
5287 | all target environments can support reverse execution. | |
5288 | ||
5289 | When a program is executed in reverse, the instructions that | |
5290 | have most recently been executed are ``un-executed'', in reverse | |
5291 | order. The program counter runs backward, following the previous | |
5292 | thread of execution in reverse. As each instruction is ``un-executed'', | |
5293 | the values of memory and/or registers that were changed by that | |
5294 | instruction are reverted to their previous states. After executing | |
5295 | a piece of source code in reverse, all side effects of that code | |
5296 | should be ``undone'', and all variables should be returned to their | |
5297 | prior values@footnote{ | |
5298 | Note that some side effects are easier to undo than others. For instance, | |
5299 | memory and registers are relatively easy, but device I/O is hard. Some | |
5300 | targets may be able undo things like device I/O, and some may not. | |
5301 | ||
5302 | The contract between @value{GDBN} and the reverse executing target | |
5303 | requires only that the target do something reasonable when | |
5304 | @value{GDBN} tells it to execute backwards, and then report the | |
5305 | results back to @value{GDBN}. Whatever the target reports back to | |
5306 | @value{GDBN}, @value{GDBN} will report back to the user. @value{GDBN} | |
5307 | assumes that the memory and registers that the target reports are in a | |
5308 | consistant state, but @value{GDBN} accepts whatever it is given. | |
5309 | }. | |
5310 | ||
5311 | If you are debugging in a target environment that supports | |
5312 | reverse execution, @value{GDBN} provides the following commands. | |
5313 | ||
5314 | @table @code | |
5315 | @kindex reverse-continue | |
5316 | @kindex rc @r{(@code{reverse-continue})} | |
5317 | @item reverse-continue @r{[}@var{ignore-count}@r{]} | |
5318 | @itemx rc @r{[}@var{ignore-count}@r{]} | |
5319 | Beginning at the point where your program last stopped, start executing | |
5320 | in reverse. Reverse execution will stop for breakpoints and synchronous | |
5321 | exceptions (signals), just like normal execution. Behavior of | |
5322 | asynchronous signals depends on the target environment. | |
5323 | ||
5324 | @kindex reverse-step | |
5325 | @kindex rs @r{(@code{step})} | |
5326 | @item reverse-step @r{[}@var{count}@r{]} | |
5327 | Run the program backward until control reaches the start of a | |
5328 | different source line; then stop it, and return control to @value{GDBN}. | |
5329 | ||
5330 | Like the @code{step} command, @code{reverse-step} will only stop | |
5331 | at the beginning of a source line. It ``un-executes'' the previously | |
5332 | executed source line. If the previous source line included calls to | |
5333 | debuggable functions, @code{reverse-step} will step (backward) into | |
5334 | the called function, stopping at the beginning of the @emph{last} | |
5335 | statement in the called function (typically a return statement). | |
5336 | ||
5337 | Also, as with the @code{step} command, if non-debuggable functions are | |
5338 | called, @code{reverse-step} will run thru them backward without stopping. | |
5339 | ||
5340 | @kindex reverse-stepi | |
5341 | @kindex rsi @r{(@code{reverse-stepi})} | |
5342 | @item reverse-stepi @r{[}@var{count}@r{]} | |
5343 | Reverse-execute one machine instruction. Note that the instruction | |
5344 | to be reverse-executed is @emph{not} the one pointed to by the program | |
5345 | counter, but the instruction executed prior to that one. For instance, | |
5346 | if the last instruction was a jump, @code{reverse-stepi} will take you | |
5347 | back from the destination of the jump to the jump instruction itself. | |
5348 | ||
5349 | @kindex reverse-next | |
5350 | @kindex rn @r{(@code{reverse-next})} | |
5351 | @item reverse-next @r{[}@var{count}@r{]} | |
5352 | Run backward to the beginning of the previous line executed in | |
5353 | the current (innermost) stack frame. If the line contains function | |
5354 | calls, they will be ``un-executed'' without stopping. Starting from | |
5355 | the first line of a function, @code{reverse-next} will take you back | |
5356 | to the caller of that function, @emph{before} the function was called, | |
5357 | just as the normal @code{next} command would take you from the last | |
5358 | line of a function back to its return to its caller | |
16af530a | 5359 | @footnote{Unless the code is too heavily optimized.}. |
bacec72f MS |
5360 | |
5361 | @kindex reverse-nexti | |
5362 | @kindex rni @r{(@code{reverse-nexti})} | |
5363 | @item reverse-nexti @r{[}@var{count}@r{]} | |
5364 | Like @code{nexti}, @code{reverse-nexti} executes a single instruction | |
5365 | in reverse, except that called functions are ``un-executed'' atomically. | |
5366 | That is, if the previously executed instruction was a return from | |
5367 | another instruction, @code{reverse-nexti} will continue to execute | |
5368 | in reverse until the call to that function (from the current stack | |
5369 | frame) is reached. | |
5370 | ||
5371 | @kindex reverse-finish | |
5372 | @item reverse-finish | |
5373 | Just as the @code{finish} command takes you to the point where the | |
5374 | current function returns, @code{reverse-finish} takes you to the point | |
5375 | where it was called. Instead of ending up at the end of the current | |
5376 | function invocation, you end up at the beginning. | |
5377 | ||
5378 | @kindex set exec-direction | |
5379 | @item set exec-direction | |
5380 | Set the direction of target execution. | |
5381 | @itemx set exec-direction reverse | |
5382 | @cindex execute forward or backward in time | |
5383 | @value{GDBN} will perform all execution commands in reverse, until the | |
5384 | exec-direction mode is changed to ``forward''. Affected commands include | |
5385 | @code{step, stepi, next, nexti, continue, and finish}. The @code{return} | |
5386 | command cannot be used in reverse mode. | |
5387 | @item set exec-direction forward | |
5388 | @value{GDBN} will perform all execution commands in the normal fashion. | |
5389 | This is the default. | |
5390 | @end table | |
5391 | ||
c906108c | 5392 | |
a2311334 EZ |
5393 | @node Process Record and Replay |
5394 | @chapter Recording Inferior's Execution and Replaying It | |
53cc454a HZ |
5395 | @cindex process record and replay |
5396 | @cindex recording inferior's execution and replaying it | |
5397 | ||
8e05493c EZ |
5398 | On some platforms, @value{GDBN} provides a special @dfn{process record |
5399 | and replay} target that can record a log of the process execution, and | |
5400 | replay it later with both forward and reverse execution commands. | |
a2311334 EZ |
5401 | |
5402 | @cindex replay mode | |
5403 | When this target is in use, if the execution log includes the record | |
5404 | for the next instruction, @value{GDBN} will debug in @dfn{replay | |
5405 | mode}. In the replay mode, the inferior does not really execute code | |
5406 | instructions. Instead, all the events that normally happen during | |
5407 | code execution are taken from the execution log. While code is not | |
5408 | really executed in replay mode, the values of registers (including the | |
5409 | program counter register) and the memory of the inferior are still | |
8e05493c EZ |
5410 | changed as they normally would. Their contents are taken from the |
5411 | execution log. | |
a2311334 EZ |
5412 | |
5413 | @cindex record mode | |
5414 | If the record for the next instruction is not in the execution log, | |
5415 | @value{GDBN} will debug in @dfn{record mode}. In this mode, the | |
5416 | inferior executes normally, and @value{GDBN} records the execution log | |
5417 | for future replay. | |
5418 | ||
8e05493c EZ |
5419 | The process record and replay target supports reverse execution |
5420 | (@pxref{Reverse Execution}), even if the platform on which the | |
5421 | inferior runs does not. However, the reverse execution is limited in | |
5422 | this case by the range of the instructions recorded in the execution | |
5423 | log. In other words, reverse execution on platforms that don't | |
5424 | support it directly can only be done in the replay mode. | |
5425 | ||
5426 | When debugging in the reverse direction, @value{GDBN} will work in | |
5427 | replay mode as long as the execution log includes the record for the | |
5428 | previous instruction; otherwise, it will work in record mode, if the | |
5429 | platform supports reverse execution, or stop if not. | |
5430 | ||
a2311334 EZ |
5431 | For architecture environments that support process record and replay, |
5432 | @value{GDBN} provides the following commands: | |
53cc454a HZ |
5433 | |
5434 | @table @code | |
5435 | @kindex target record | |
5436 | @kindex record | |
5437 | @kindex rec | |
5438 | @item target record | |
a2311334 EZ |
5439 | This command starts the process record and replay target. The process |
5440 | record and replay target can only debug a process that is already | |
5441 | running. Therefore, you need first to start the process with the | |
5442 | @kbd{run} or @kbd{start} commands, and then start the recording with | |
5443 | the @kbd{target record} command. | |
5444 | ||
5445 | Both @code{record} and @code{rec} are aliases of @code{target record}. | |
5446 | ||
5447 | @cindex displaced stepping, and process record and replay | |
5448 | Displaced stepping (@pxref{Maintenance Commands,, displaced stepping}) | |
5449 | will be automatically disabled when process record and replay target | |
5450 | is started. That's because the process record and replay target | |
5451 | doesn't support displaced stepping. | |
5452 | ||
5453 | @cindex non-stop mode, and process record and replay | |
5454 | @cindex asynchronous execution, and process record and replay | |
5455 | If the inferior is in the non-stop mode (@pxref{Non-Stop Mode}) or in | |
5456 | the asynchronous execution mode (@pxref{Background Execution}), the | |
5457 | process record and replay target cannot be started because it doesn't | |
5458 | support these two modes. | |
53cc454a HZ |
5459 | |
5460 | @kindex record stop | |
5461 | @kindex rec s | |
5462 | @item record stop | |
a2311334 EZ |
5463 | Stop the process record and replay target. When process record and |
5464 | replay target stops, the entire execution log will be deleted and the | |
5465 | inferior will either be terminated, or will remain in its final state. | |
53cc454a | 5466 | |
a2311334 EZ |
5467 | When you stop the process record and replay target in record mode (at |
5468 | the end of the execution log), the inferior will be stopped at the | |
5469 | next instruction that would have been recorded. In other words, if | |
5470 | you record for a while and then stop recording, the inferior process | |
5471 | will be left in the same state as if the recording never happened. | |
53cc454a | 5472 | |
a2311334 EZ |
5473 | On the other hand, if the process record and replay target is stopped |
5474 | while in replay mode (that is, not at the end of the execution log, | |
5475 | but at some earlier point), the inferior process will become ``live'' | |
5476 | at that earlier state, and it will then be possible to continue the | |
5477 | usual ``live'' debugging of the process from that state. | |
53cc454a | 5478 | |
a2311334 EZ |
5479 | When the inferior process exits, or @value{GDBN} detaches from it, |
5480 | process record and replay target will automatically stop itself. | |
53cc454a HZ |
5481 | |
5482 | @kindex set record insn-number-max | |
5483 | @item set record insn-number-max @var{limit} | |
5484 | Set the limit of instructions to be recorded. Default value is 200000. | |
5485 | ||
a2311334 EZ |
5486 | If @var{limit} is a positive number, then @value{GDBN} will start |
5487 | deleting instructions from the log once the number of the record | |
5488 | instructions becomes greater than @var{limit}. For every new recorded | |
5489 | instruction, @value{GDBN} will delete the earliest recorded | |
5490 | instruction to keep the number of recorded instructions at the limit. | |
5491 | (Since deleting recorded instructions loses information, @value{GDBN} | |
5492 | lets you control what happens when the limit is reached, by means of | |
5493 | the @code{stop-at-limit} option, described below.) | |
53cc454a | 5494 | |
a2311334 EZ |
5495 | If @var{limit} is zero, @value{GDBN} will never delete recorded |
5496 | instructions from the execution log. The number of recorded | |
5497 | instructions is unlimited in this case. | |
53cc454a HZ |
5498 | |
5499 | @kindex show record insn-number-max | |
5500 | @item show record insn-number-max | |
a2311334 | 5501 | Show the limit of instructions to be recorded. |
53cc454a HZ |
5502 | |
5503 | @kindex set record stop-at-limit | |
a2311334 EZ |
5504 | @item set record stop-at-limit |
5505 | Control the behavior when the number of recorded instructions reaches | |
5506 | the limit. If ON (the default), @value{GDBN} will stop when the limit | |
5507 | is reached for the first time and ask you whether you want to stop the | |
5508 | inferior or continue running it and recording the execution log. If | |
5509 | you decide to continue recording, each new recorded instruction will | |
5510 | cause the oldest one to be deleted. | |
53cc454a | 5511 | |
a2311334 EZ |
5512 | If this option is OFF, @value{GDBN} will automatically delete the |
5513 | oldest record to make room for each new one, without asking. | |
53cc454a HZ |
5514 | |
5515 | @kindex show record stop-at-limit | |
5516 | @item show record stop-at-limit | |
a2311334 | 5517 | Show the current setting of @code{stop-at-limit}. |
53cc454a | 5518 | |
29153c24 MS |
5519 | @kindex info record |
5520 | @item info record | |
5521 | Show various statistics about the state of process record and its | |
5522 | in-memory execution log buffer, including: | |
5523 | ||
5524 | @itemize @bullet | |
5525 | @item | |
5526 | Whether in record mode or replay mode. | |
5527 | @item | |
5528 | Lowest recorded instruction number (counting from when the current execution log started recording instructions). | |
5529 | @item | |
5530 | Highest recorded instruction number. | |
5531 | @item | |
5532 | Current instruction about to be replayed (if in replay mode). | |
5533 | @item | |
5534 | Number of instructions contained in the execution log. | |
5535 | @item | |
5536 | Maximum number of instructions that may be contained in the execution log. | |
5537 | @end itemize | |
53cc454a HZ |
5538 | |
5539 | @kindex record delete | |
5540 | @kindex rec del | |
5541 | @item record delete | |
a2311334 | 5542 | When record target runs in replay mode (``in the past''), delete the |
53cc454a | 5543 | subsequent execution log and begin to record a new execution log starting |
a2311334 | 5544 | from the current address. This means you will abandon the previously |
53cc454a HZ |
5545 | recorded ``future'' and begin recording a new ``future''. |
5546 | @end table | |
5547 | ||
5548 | ||
6d2ebf8b | 5549 | @node Stack |
c906108c SS |
5550 | @chapter Examining the Stack |
5551 | ||
5552 | When your program has stopped, the first thing you need to know is where it | |
5553 | stopped and how it got there. | |
5554 | ||
5555 | @cindex call stack | |
5d161b24 DB |
5556 | Each time your program performs a function call, information about the call |
5557 | is generated. | |
5558 | That information includes the location of the call in your program, | |
5559 | the arguments of the call, | |
c906108c | 5560 | and the local variables of the function being called. |
5d161b24 | 5561 | The information is saved in a block of data called a @dfn{stack frame}. |
c906108c SS |
5562 | The stack frames are allocated in a region of memory called the @dfn{call |
5563 | stack}. | |
5564 | ||
5565 | When your program stops, the @value{GDBN} commands for examining the | |
5566 | stack allow you to see all of this information. | |
5567 | ||
5568 | @cindex selected frame | |
5569 | One of the stack frames is @dfn{selected} by @value{GDBN} and many | |
5570 | @value{GDBN} commands refer implicitly to the selected frame. In | |
5571 | particular, whenever you ask @value{GDBN} for the value of a variable in | |
5572 | your program, the value is found in the selected frame. There are | |
5573 | special @value{GDBN} commands to select whichever frame you are | |
79a6e687 | 5574 | interested in. @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5575 | |
5576 | When your program stops, @value{GDBN} automatically selects the | |
5d161b24 | 5577 | currently executing frame and describes it briefly, similar to the |
79a6e687 | 5578 | @code{frame} command (@pxref{Frame Info, ,Information about a Frame}). |
c906108c SS |
5579 | |
5580 | @menu | |
5581 | * Frames:: Stack frames | |
5582 | * Backtrace:: Backtraces | |
5583 | * Selection:: Selecting a frame | |
5584 | * Frame Info:: Information on a frame | |
c906108c SS |
5585 | |
5586 | @end menu | |
5587 | ||
6d2ebf8b | 5588 | @node Frames |
79a6e687 | 5589 | @section Stack Frames |
c906108c | 5590 | |
d4f3574e | 5591 | @cindex frame, definition |
c906108c SS |
5592 | @cindex stack frame |
5593 | The call stack is divided up into contiguous pieces called @dfn{stack | |
5594 | frames}, or @dfn{frames} for short; each frame is the data associated | |
5595 | with one call to one function. The frame contains the arguments given | |
5596 | to the function, the function's local variables, and the address at | |
5597 | which the function is executing. | |
5598 | ||
5599 | @cindex initial frame | |
5600 | @cindex outermost frame | |
5601 | @cindex innermost frame | |
5602 | When your program is started, the stack has only one frame, that of the | |
5603 | function @code{main}. This is called the @dfn{initial} frame or the | |
5604 | @dfn{outermost} frame. Each time a function is called, a new frame is | |
5605 | made. Each time a function returns, the frame for that function invocation | |
5606 | is eliminated. If a function is recursive, there can be many frames for | |
5607 | the same function. The frame for the function in which execution is | |
5608 | actually occurring is called the @dfn{innermost} frame. This is the most | |
5609 | recently created of all the stack frames that still exist. | |
5610 | ||
5611 | @cindex frame pointer | |
5612 | Inside your program, stack frames are identified by their addresses. A | |
5613 | stack frame consists of many bytes, each of which has its own address; each | |
5614 | kind of computer has a convention for choosing one byte whose | |
5615 | address serves as the address of the frame. Usually this address is kept | |
e09f16f9 EZ |
5616 | in a register called the @dfn{frame pointer register} |
5617 | (@pxref{Registers, $fp}) while execution is going on in that frame. | |
c906108c SS |
5618 | |
5619 | @cindex frame number | |
5620 | @value{GDBN} assigns numbers to all existing stack frames, starting with | |
5621 | zero for the innermost frame, one for the frame that called it, | |
5622 | and so on upward. These numbers do not really exist in your program; | |
5623 | they are assigned by @value{GDBN} to give you a way of designating stack | |
5624 | frames in @value{GDBN} commands. | |
5625 | ||
6d2ebf8b SS |
5626 | @c The -fomit-frame-pointer below perennially causes hbox overflow |
5627 | @c underflow problems. | |
c906108c SS |
5628 | @cindex frameless execution |
5629 | Some compilers provide a way to compile functions so that they operate | |
e22ea452 | 5630 | without stack frames. (For example, the @value{NGCC} option |
474c8240 | 5631 | @smallexample |
6d2ebf8b | 5632 | @samp{-fomit-frame-pointer} |
474c8240 | 5633 | @end smallexample |
6d2ebf8b | 5634 | generates functions without a frame.) |
c906108c SS |
5635 | This is occasionally done with heavily used library functions to save |
5636 | the frame setup time. @value{GDBN} has limited facilities for dealing | |
5637 | with these function invocations. If the innermost function invocation | |
5638 | has no stack frame, @value{GDBN} nevertheless regards it as though | |
5639 | it had a separate frame, which is numbered zero as usual, allowing | |
5640 | correct tracing of the function call chain. However, @value{GDBN} has | |
5641 | no provision for frameless functions elsewhere in the stack. | |
5642 | ||
5643 | @table @code | |
d4f3574e | 5644 | @kindex frame@r{, command} |
41afff9a | 5645 | @cindex current stack frame |
c906108c | 5646 | @item frame @var{args} |
5d161b24 | 5647 | The @code{frame} command allows you to move from one stack frame to another, |
c906108c | 5648 | and to print the stack frame you select. @var{args} may be either the |
5d161b24 DB |
5649 | address of the frame or the stack frame number. Without an argument, |
5650 | @code{frame} prints the current stack frame. | |
c906108c SS |
5651 | |
5652 | @kindex select-frame | |
41afff9a | 5653 | @cindex selecting frame silently |
c906108c SS |
5654 | @item select-frame |
5655 | The @code{select-frame} command allows you to move from one stack frame | |
5656 | to another without printing the frame. This is the silent version of | |
5657 | @code{frame}. | |
5658 | @end table | |
5659 | ||
6d2ebf8b | 5660 | @node Backtrace |
c906108c SS |
5661 | @section Backtraces |
5662 | ||
09d4efe1 EZ |
5663 | @cindex traceback |
5664 | @cindex call stack traces | |
c906108c SS |
5665 | A backtrace is a summary of how your program got where it is. It shows one |
5666 | line per frame, for many frames, starting with the currently executing | |
5667 | frame (frame zero), followed by its caller (frame one), and on up the | |
5668 | stack. | |
5669 | ||
5670 | @table @code | |
5671 | @kindex backtrace | |
41afff9a | 5672 | @kindex bt @r{(@code{backtrace})} |
c906108c SS |
5673 | @item backtrace |
5674 | @itemx bt | |
5675 | Print a backtrace of the entire stack: one line per frame for all | |
5676 | frames in the stack. | |
5677 | ||
5678 | You can stop the backtrace at any time by typing the system interrupt | |
c8aa23ab | 5679 | character, normally @kbd{Ctrl-c}. |
c906108c SS |
5680 | |
5681 | @item backtrace @var{n} | |
5682 | @itemx bt @var{n} | |
5683 | Similar, but print only the innermost @var{n} frames. | |
5684 | ||
5685 | @item backtrace -@var{n} | |
5686 | @itemx bt -@var{n} | |
5687 | Similar, but print only the outermost @var{n} frames. | |
0f061b69 NR |
5688 | |
5689 | @item backtrace full | |
0f061b69 | 5690 | @itemx bt full |
dd74f6ae NR |
5691 | @itemx bt full @var{n} |
5692 | @itemx bt full -@var{n} | |
e7109c7e | 5693 | Print the values of the local variables also. @var{n} specifies the |
286ba84d | 5694 | number of frames to print, as described above. |
c906108c SS |
5695 | @end table |
5696 | ||
5697 | @kindex where | |
5698 | @kindex info stack | |
c906108c SS |
5699 | The names @code{where} and @code{info stack} (abbreviated @code{info s}) |
5700 | are additional aliases for @code{backtrace}. | |
5701 | ||
839c27b7 EZ |
5702 | @cindex multiple threads, backtrace |
5703 | In a multi-threaded program, @value{GDBN} by default shows the | |
5704 | backtrace only for the current thread. To display the backtrace for | |
5705 | several or all of the threads, use the command @code{thread apply} | |
5706 | (@pxref{Threads, thread apply}). For example, if you type @kbd{thread | |
5707 | apply all backtrace}, @value{GDBN} will display the backtrace for all | |
5708 | the threads; this is handy when you debug a core dump of a | |
5709 | multi-threaded program. | |
5710 | ||
c906108c SS |
5711 | Each line in the backtrace shows the frame number and the function name. |
5712 | The program counter value is also shown---unless you use @code{set | |
5713 | print address off}. The backtrace also shows the source file name and | |
5714 | line number, as well as the arguments to the function. The program | |
5715 | counter value is omitted if it is at the beginning of the code for that | |
5716 | line number. | |
5717 | ||
5718 | Here is an example of a backtrace. It was made with the command | |
5719 | @samp{bt 3}, so it shows the innermost three frames. | |
5720 | ||
5721 | @smallexample | |
5722 | @group | |
5d161b24 | 5723 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) |
c906108c | 5724 | at builtin.c:993 |
4f5376b2 | 5725 | #1 0x6e38 in expand_macro (sym=0x2b600, data=...) at macro.c:242 |
c906108c SS |
5726 | #2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08) |
5727 | at macro.c:71 | |
5728 | (More stack frames follow...) | |
5729 | @end group | |
5730 | @end smallexample | |
5731 | ||
5732 | @noindent | |
5733 | The display for frame zero does not begin with a program counter | |
5734 | value, indicating that your program has stopped at the beginning of the | |
5735 | code for line @code{993} of @code{builtin.c}. | |
5736 | ||
4f5376b2 JB |
5737 | @noindent |
5738 | The value of parameter @code{data} in frame 1 has been replaced by | |
5739 | @code{@dots{}}. By default, @value{GDBN} prints the value of a parameter | |
5740 | only if it is a scalar (integer, pointer, enumeration, etc). See command | |
5741 | @kbd{set print frame-arguments} in @ref{Print Settings} for more details | |
5742 | on how to configure the way function parameter values are printed. | |
5743 | ||
18999be5 EZ |
5744 | @cindex value optimized out, in backtrace |
5745 | @cindex function call arguments, optimized out | |
5746 | If your program was compiled with optimizations, some compilers will | |
5747 | optimize away arguments passed to functions if those arguments are | |
5748 | never used after the call. Such optimizations generate code that | |
5749 | passes arguments through registers, but doesn't store those arguments | |
5750 | in the stack frame. @value{GDBN} has no way of displaying such | |
5751 | arguments in stack frames other than the innermost one. Here's what | |
5752 | such a backtrace might look like: | |
5753 | ||
5754 | @smallexample | |
5755 | @group | |
5756 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) | |
5757 | at builtin.c:993 | |
5758 | #1 0x6e38 in expand_macro (sym=<value optimized out>) at macro.c:242 | |
5759 | #2 0x6840 in expand_token (obs=0x0, t=<value optimized out>, td=0xf7fffb08) | |
5760 | at macro.c:71 | |
5761 | (More stack frames follow...) | |
5762 | @end group | |
5763 | @end smallexample | |
5764 | ||
5765 | @noindent | |
5766 | The values of arguments that were not saved in their stack frames are | |
5767 | shown as @samp{<value optimized out>}. | |
5768 | ||
5769 | If you need to display the values of such optimized-out arguments, | |
5770 | either deduce that from other variables whose values depend on the one | |
5771 | you are interested in, or recompile without optimizations. | |
5772 | ||
a8f24a35 EZ |
5773 | @cindex backtrace beyond @code{main} function |
5774 | @cindex program entry point | |
5775 | @cindex startup code, and backtrace | |
25d29d70 AC |
5776 | Most programs have a standard user entry point---a place where system |
5777 | libraries and startup code transition into user code. For C this is | |
d416eeec EZ |
5778 | @code{main}@footnote{ |
5779 | Note that embedded programs (the so-called ``free-standing'' | |
5780 | environment) are not required to have a @code{main} function as the | |
5781 | entry point. They could even have multiple entry points.}. | |
5782 | When @value{GDBN} finds the entry function in a backtrace | |
25d29d70 AC |
5783 | it will terminate the backtrace, to avoid tracing into highly |
5784 | system-specific (and generally uninteresting) code. | |
5785 | ||
5786 | If you need to examine the startup code, or limit the number of levels | |
5787 | in a backtrace, you can change this behavior: | |
95f90d25 DJ |
5788 | |
5789 | @table @code | |
25d29d70 AC |
5790 | @item set backtrace past-main |
5791 | @itemx set backtrace past-main on | |
4644b6e3 | 5792 | @kindex set backtrace |
25d29d70 AC |
5793 | Backtraces will continue past the user entry point. |
5794 | ||
5795 | @item set backtrace past-main off | |
95f90d25 DJ |
5796 | Backtraces will stop when they encounter the user entry point. This is the |
5797 | default. | |
5798 | ||
25d29d70 | 5799 | @item show backtrace past-main |
4644b6e3 | 5800 | @kindex show backtrace |
25d29d70 AC |
5801 | Display the current user entry point backtrace policy. |
5802 | ||
2315ffec RC |
5803 | @item set backtrace past-entry |
5804 | @itemx set backtrace past-entry on | |
a8f24a35 | 5805 | Backtraces will continue past the internal entry point of an application. |
2315ffec RC |
5806 | This entry point is encoded by the linker when the application is built, |
5807 | and is likely before the user entry point @code{main} (or equivalent) is called. | |
5808 | ||
5809 | @item set backtrace past-entry off | |
d3e8051b | 5810 | Backtraces will stop when they encounter the internal entry point of an |
2315ffec RC |
5811 | application. This is the default. |
5812 | ||
5813 | @item show backtrace past-entry | |
5814 | Display the current internal entry point backtrace policy. | |
5815 | ||
25d29d70 AC |
5816 | @item set backtrace limit @var{n} |
5817 | @itemx set backtrace limit 0 | |
5818 | @cindex backtrace limit | |
5819 | Limit the backtrace to @var{n} levels. A value of zero means | |
5820 | unlimited. | |
95f90d25 | 5821 | |
25d29d70 AC |
5822 | @item show backtrace limit |
5823 | Display the current limit on backtrace levels. | |
95f90d25 DJ |
5824 | @end table |
5825 | ||
6d2ebf8b | 5826 | @node Selection |
79a6e687 | 5827 | @section Selecting a Frame |
c906108c SS |
5828 | |
5829 | Most commands for examining the stack and other data in your program work on | |
5830 | whichever stack frame is selected at the moment. Here are the commands for | |
5831 | selecting a stack frame; all of them finish by printing a brief description | |
5832 | of the stack frame just selected. | |
5833 | ||
5834 | @table @code | |
d4f3574e | 5835 | @kindex frame@r{, selecting} |
41afff9a | 5836 | @kindex f @r{(@code{frame})} |
c906108c SS |
5837 | @item frame @var{n} |
5838 | @itemx f @var{n} | |
5839 | Select frame number @var{n}. Recall that frame zero is the innermost | |
5840 | (currently executing) frame, frame one is the frame that called the | |
5841 | innermost one, and so on. The highest-numbered frame is the one for | |
5842 | @code{main}. | |
5843 | ||
5844 | @item frame @var{addr} | |
5845 | @itemx f @var{addr} | |
5846 | Select the frame at address @var{addr}. This is useful mainly if the | |
5847 | chaining of stack frames has been damaged by a bug, making it | |
5848 | impossible for @value{GDBN} to assign numbers properly to all frames. In | |
5849 | addition, this can be useful when your program has multiple stacks and | |
5850 | switches between them. | |
5851 | ||
c906108c SS |
5852 | On the SPARC architecture, @code{frame} needs two addresses to |
5853 | select an arbitrary frame: a frame pointer and a stack pointer. | |
5854 | ||
5855 | On the MIPS and Alpha architecture, it needs two addresses: a stack | |
5856 | pointer and a program counter. | |
5857 | ||
5858 | On the 29k architecture, it needs three addresses: a register stack | |
5859 | pointer, a program counter, and a memory stack pointer. | |
c906108c SS |
5860 | |
5861 | @kindex up | |
5862 | @item up @var{n} | |
5863 | Move @var{n} frames up the stack. For positive numbers @var{n}, this | |
5864 | advances toward the outermost frame, to higher frame numbers, to frames | |
5865 | that have existed longer. @var{n} defaults to one. | |
5866 | ||
5867 | @kindex down | |
41afff9a | 5868 | @kindex do @r{(@code{down})} |
c906108c SS |
5869 | @item down @var{n} |
5870 | Move @var{n} frames down the stack. For positive numbers @var{n}, this | |
5871 | advances toward the innermost frame, to lower frame numbers, to frames | |
5872 | that were created more recently. @var{n} defaults to one. You may | |
5873 | abbreviate @code{down} as @code{do}. | |
5874 | @end table | |
5875 | ||
5876 | All of these commands end by printing two lines of output describing the | |
5877 | frame. The first line shows the frame number, the function name, the | |
5878 | arguments, and the source file and line number of execution in that | |
5d161b24 | 5879 | frame. The second line shows the text of that source line. |
c906108c SS |
5880 | |
5881 | @need 1000 | |
5882 | For example: | |
5883 | ||
5884 | @smallexample | |
5885 | @group | |
5886 | (@value{GDBP}) up | |
5887 | #1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc) | |
5888 | at env.c:10 | |
5889 | 10 read_input_file (argv[i]); | |
5890 | @end group | |
5891 | @end smallexample | |
5892 | ||
5893 | After such a printout, the @code{list} command with no arguments | |
5894 | prints ten lines centered on the point of execution in the frame. | |
87885426 FN |
5895 | You can also edit the program at the point of execution with your favorite |
5896 | editing program by typing @code{edit}. | |
79a6e687 | 5897 | @xref{List, ,Printing Source Lines}, |
87885426 | 5898 | for details. |
c906108c SS |
5899 | |
5900 | @table @code | |
5901 | @kindex down-silently | |
5902 | @kindex up-silently | |
5903 | @item up-silently @var{n} | |
5904 | @itemx down-silently @var{n} | |
5905 | These two commands are variants of @code{up} and @code{down}, | |
5906 | respectively; they differ in that they do their work silently, without | |
5907 | causing display of the new frame. They are intended primarily for use | |
5908 | in @value{GDBN} command scripts, where the output might be unnecessary and | |
5909 | distracting. | |
5910 | @end table | |
5911 | ||
6d2ebf8b | 5912 | @node Frame Info |
79a6e687 | 5913 | @section Information About a Frame |
c906108c SS |
5914 | |
5915 | There are several other commands to print information about the selected | |
5916 | stack frame. | |
5917 | ||
5918 | @table @code | |
5919 | @item frame | |
5920 | @itemx f | |
5921 | When used without any argument, this command does not change which | |
5922 | frame is selected, but prints a brief description of the currently | |
5923 | selected stack frame. It can be abbreviated @code{f}. With an | |
5924 | argument, this command is used to select a stack frame. | |
79a6e687 | 5925 | @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5926 | |
5927 | @kindex info frame | |
41afff9a | 5928 | @kindex info f @r{(@code{info frame})} |
c906108c SS |
5929 | @item info frame |
5930 | @itemx info f | |
5931 | This command prints a verbose description of the selected stack frame, | |
5932 | including: | |
5933 | ||
5934 | @itemize @bullet | |
5d161b24 DB |
5935 | @item |
5936 | the address of the frame | |
c906108c SS |
5937 | @item |
5938 | the address of the next frame down (called by this frame) | |
5939 | @item | |
5940 | the address of the next frame up (caller of this frame) | |
5941 | @item | |
5942 | the language in which the source code corresponding to this frame is written | |
5943 | @item | |
5944 | the address of the frame's arguments | |
5945 | @item | |
d4f3574e SS |
5946 | the address of the frame's local variables |
5947 | @item | |
c906108c SS |
5948 | the program counter saved in it (the address of execution in the caller frame) |
5949 | @item | |
5950 | which registers were saved in the frame | |
5951 | @end itemize | |
5952 | ||
5953 | @noindent The verbose description is useful when | |
5954 | something has gone wrong that has made the stack format fail to fit | |
5955 | the usual conventions. | |
5956 | ||
5957 | @item info frame @var{addr} | |
5958 | @itemx info f @var{addr} | |
5959 | Print a verbose description of the frame at address @var{addr}, without | |
5960 | selecting that frame. The selected frame remains unchanged by this | |
5961 | command. This requires the same kind of address (more than one for some | |
5962 | architectures) that you specify in the @code{frame} command. | |
79a6e687 | 5963 | @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5964 | |
5965 | @kindex info args | |
5966 | @item info args | |
5967 | Print the arguments of the selected frame, each on a separate line. | |
5968 | ||
5969 | @item info locals | |
5970 | @kindex info locals | |
5971 | Print the local variables of the selected frame, each on a separate | |
5972 | line. These are all variables (declared either static or automatic) | |
5973 | accessible at the point of execution of the selected frame. | |
5974 | ||
c906108c | 5975 | @kindex info catch |
d4f3574e SS |
5976 | @cindex catch exceptions, list active handlers |
5977 | @cindex exception handlers, how to list | |
c906108c SS |
5978 | @item info catch |
5979 | Print a list of all the exception handlers that are active in the | |
5980 | current stack frame at the current point of execution. To see other | |
5981 | exception handlers, visit the associated frame (using the @code{up}, | |
5982 | @code{down}, or @code{frame} commands); then type @code{info catch}. | |
79a6e687 | 5983 | @xref{Set Catchpoints, , Setting Catchpoints}. |
53a5351d | 5984 | |
c906108c SS |
5985 | @end table |
5986 | ||
c906108c | 5987 | |
6d2ebf8b | 5988 | @node Source |
c906108c SS |
5989 | @chapter Examining Source Files |
5990 | ||
5991 | @value{GDBN} can print parts of your program's source, since the debugging | |
5992 | information recorded in the program tells @value{GDBN} what source files were | |
5993 | used to build it. When your program stops, @value{GDBN} spontaneously prints | |
5994 | the line where it stopped. Likewise, when you select a stack frame | |
79a6e687 | 5995 | (@pxref{Selection, ,Selecting a Frame}), @value{GDBN} prints the line where |
c906108c SS |
5996 | execution in that frame has stopped. You can print other portions of |
5997 | source files by explicit command. | |
5998 | ||
7a292a7a | 5999 | If you use @value{GDBN} through its @sc{gnu} Emacs interface, you may |
d4f3574e | 6000 | prefer to use Emacs facilities to view source; see @ref{Emacs, ,Using |
7a292a7a | 6001 | @value{GDBN} under @sc{gnu} Emacs}. |
c906108c SS |
6002 | |
6003 | @menu | |
6004 | * List:: Printing source lines | |
2a25a5ba | 6005 | * Specify Location:: How to specify code locations |
87885426 | 6006 | * Edit:: Editing source files |
c906108c | 6007 | * Search:: Searching source files |
c906108c SS |
6008 | * Source Path:: Specifying source directories |
6009 | * Machine Code:: Source and machine code | |
6010 | @end menu | |
6011 | ||
6d2ebf8b | 6012 | @node List |
79a6e687 | 6013 | @section Printing Source Lines |
c906108c SS |
6014 | |
6015 | @kindex list | |
41afff9a | 6016 | @kindex l @r{(@code{list})} |
c906108c | 6017 | To print lines from a source file, use the @code{list} command |
5d161b24 | 6018 | (abbreviated @code{l}). By default, ten lines are printed. |
2a25a5ba EZ |
6019 | There are several ways to specify what part of the file you want to |
6020 | print; see @ref{Specify Location}, for the full list. | |
c906108c SS |
6021 | |
6022 | Here are the forms of the @code{list} command most commonly used: | |
6023 | ||
6024 | @table @code | |
6025 | @item list @var{linenum} | |
6026 | Print lines centered around line number @var{linenum} in the | |
6027 | current source file. | |
6028 | ||
6029 | @item list @var{function} | |
6030 | Print lines centered around the beginning of function | |
6031 | @var{function}. | |
6032 | ||
6033 | @item list | |
6034 | Print more lines. If the last lines printed were printed with a | |
6035 | @code{list} command, this prints lines following the last lines | |
6036 | printed; however, if the last line printed was a solitary line printed | |
6037 | as part of displaying a stack frame (@pxref{Stack, ,Examining the | |
6038 | Stack}), this prints lines centered around that line. | |
6039 | ||
6040 | @item list - | |
6041 | Print lines just before the lines last printed. | |
6042 | @end table | |
6043 | ||
9c16f35a | 6044 | @cindex @code{list}, how many lines to display |
c906108c SS |
6045 | By default, @value{GDBN} prints ten source lines with any of these forms of |
6046 | the @code{list} command. You can change this using @code{set listsize}: | |
6047 | ||
6048 | @table @code | |
6049 | @kindex set listsize | |
6050 | @item set listsize @var{count} | |
6051 | Make the @code{list} command display @var{count} source lines (unless | |
6052 | the @code{list} argument explicitly specifies some other number). | |
6053 | ||
6054 | @kindex show listsize | |
6055 | @item show listsize | |
6056 | Display the number of lines that @code{list} prints. | |
6057 | @end table | |
6058 | ||
6059 | Repeating a @code{list} command with @key{RET} discards the argument, | |
6060 | so it is equivalent to typing just @code{list}. This is more useful | |
6061 | than listing the same lines again. An exception is made for an | |
6062 | argument of @samp{-}; that argument is preserved in repetition so that | |
6063 | each repetition moves up in the source file. | |
6064 | ||
c906108c SS |
6065 | In general, the @code{list} command expects you to supply zero, one or two |
6066 | @dfn{linespecs}. Linespecs specify source lines; there are several ways | |
2a25a5ba EZ |
6067 | of writing them (@pxref{Specify Location}), but the effect is always |
6068 | to specify some source line. | |
6069 | ||
c906108c SS |
6070 | Here is a complete description of the possible arguments for @code{list}: |
6071 | ||
6072 | @table @code | |
6073 | @item list @var{linespec} | |
6074 | Print lines centered around the line specified by @var{linespec}. | |
6075 | ||
6076 | @item list @var{first},@var{last} | |
6077 | Print lines from @var{first} to @var{last}. Both arguments are | |
2a25a5ba EZ |
6078 | linespecs. When a @code{list} command has two linespecs, and the |
6079 | source file of the second linespec is omitted, this refers to | |
6080 | the same source file as the first linespec. | |
c906108c SS |
6081 | |
6082 | @item list ,@var{last} | |
6083 | Print lines ending with @var{last}. | |
6084 | ||
6085 | @item list @var{first}, | |
6086 | Print lines starting with @var{first}. | |
6087 | ||
6088 | @item list + | |
6089 | Print lines just after the lines last printed. | |
6090 | ||
6091 | @item list - | |
6092 | Print lines just before the lines last printed. | |
6093 | ||
6094 | @item list | |
6095 | As described in the preceding table. | |
6096 | @end table | |
6097 | ||
2a25a5ba EZ |
6098 | @node Specify Location |
6099 | @section Specifying a Location | |
6100 | @cindex specifying location | |
6101 | @cindex linespec | |
c906108c | 6102 | |
2a25a5ba EZ |
6103 | Several @value{GDBN} commands accept arguments that specify a location |
6104 | of your program's code. Since @value{GDBN} is a source-level | |
6105 | debugger, a location usually specifies some line in the source code; | |
6106 | for that reason, locations are also known as @dfn{linespecs}. | |
c906108c | 6107 | |
2a25a5ba EZ |
6108 | Here are all the different ways of specifying a code location that |
6109 | @value{GDBN} understands: | |
c906108c | 6110 | |
2a25a5ba EZ |
6111 | @table @code |
6112 | @item @var{linenum} | |
6113 | Specifies the line number @var{linenum} of the current source file. | |
c906108c | 6114 | |
2a25a5ba EZ |
6115 | @item -@var{offset} |
6116 | @itemx +@var{offset} | |
6117 | Specifies the line @var{offset} lines before or after the @dfn{current | |
6118 | line}. For the @code{list} command, the current line is the last one | |
6119 | printed; for the breakpoint commands, this is the line at which | |
6120 | execution stopped in the currently selected @dfn{stack frame} | |
6121 | (@pxref{Frames, ,Frames}, for a description of stack frames.) When | |
6122 | used as the second of the two linespecs in a @code{list} command, | |
6123 | this specifies the line @var{offset} lines up or down from the first | |
6124 | linespec. | |
6125 | ||
6126 | @item @var{filename}:@var{linenum} | |
6127 | Specifies the line @var{linenum} in the source file @var{filename}. | |
c906108c SS |
6128 | |
6129 | @item @var{function} | |
6130 | Specifies the line that begins the body of the function @var{function}. | |
2a25a5ba | 6131 | For example, in C, this is the line with the open brace. |
c906108c SS |
6132 | |
6133 | @item @var{filename}:@var{function} | |
2a25a5ba EZ |
6134 | Specifies the line that begins the body of the function @var{function} |
6135 | in the file @var{filename}. You only need the file name with a | |
6136 | function name to avoid ambiguity when there are identically named | |
6137 | functions in different source files. | |
c906108c SS |
6138 | |
6139 | @item *@var{address} | |
2a25a5ba EZ |
6140 | Specifies the program address @var{address}. For line-oriented |
6141 | commands, such as @code{list} and @code{edit}, this specifies a source | |
6142 | line that contains @var{address}. For @code{break} and other | |
6143 | breakpoint oriented commands, this can be used to set breakpoints in | |
6144 | parts of your program which do not have debugging information or | |
6145 | source files. | |
6146 | ||
6147 | Here @var{address} may be any expression valid in the current working | |
6148 | language (@pxref{Languages, working language}) that specifies a code | |
5fa54e5d EZ |
6149 | address. In addition, as a convenience, @value{GDBN} extends the |
6150 | semantics of expressions used in locations to cover the situations | |
6151 | that frequently happen during debugging. Here are the various forms | |
6152 | of @var{address}: | |
2a25a5ba EZ |
6153 | |
6154 | @table @code | |
6155 | @item @var{expression} | |
6156 | Any expression valid in the current working language. | |
6157 | ||
6158 | @item @var{funcaddr} | |
6159 | An address of a function or procedure derived from its name. In C, | |
6160 | C@t{++}, Java, Objective-C, Fortran, minimal, and assembly, this is | |
6161 | simply the function's name @var{function} (and actually a special case | |
6162 | of a valid expression). In Pascal and Modula-2, this is | |
6163 | @code{&@var{function}}. In Ada, this is @code{@var{function}'Address} | |
6164 | (although the Pascal form also works). | |
6165 | ||
6166 | This form specifies the address of the function's first instruction, | |
6167 | before the stack frame and arguments have been set up. | |
6168 | ||
6169 | @item '@var{filename}'::@var{funcaddr} | |
6170 | Like @var{funcaddr} above, but also specifies the name of the source | |
6171 | file explicitly. This is useful if the name of the function does not | |
6172 | specify the function unambiguously, e.g., if there are several | |
6173 | functions with identical names in different source files. | |
c906108c SS |
6174 | @end table |
6175 | ||
2a25a5ba EZ |
6176 | @end table |
6177 | ||
6178 | ||
87885426 | 6179 | @node Edit |
79a6e687 | 6180 | @section Editing Source Files |
87885426 FN |
6181 | @cindex editing source files |
6182 | ||
6183 | @kindex edit | |
6184 | @kindex e @r{(@code{edit})} | |
6185 | To edit the lines in a source file, use the @code{edit} command. | |
6186 | The editing program of your choice | |
6187 | is invoked with the current line set to | |
6188 | the active line in the program. | |
6189 | Alternatively, there are several ways to specify what part of the file you | |
2a25a5ba | 6190 | want to print if you want to see other parts of the program: |
87885426 FN |
6191 | |
6192 | @table @code | |
2a25a5ba EZ |
6193 | @item edit @var{location} |
6194 | Edit the source file specified by @code{location}. Editing starts at | |
6195 | that @var{location}, e.g., at the specified source line of the | |
6196 | specified file. @xref{Specify Location}, for all the possible forms | |
6197 | of the @var{location} argument; here are the forms of the @code{edit} | |
6198 | command most commonly used: | |
87885426 | 6199 | |
2a25a5ba | 6200 | @table @code |
87885426 FN |
6201 | @item edit @var{number} |
6202 | Edit the current source file with @var{number} as the active line number. | |
6203 | ||
6204 | @item edit @var{function} | |
6205 | Edit the file containing @var{function} at the beginning of its definition. | |
2a25a5ba | 6206 | @end table |
87885426 | 6207 | |
87885426 FN |
6208 | @end table |
6209 | ||
79a6e687 | 6210 | @subsection Choosing your Editor |
87885426 FN |
6211 | You can customize @value{GDBN} to use any editor you want |
6212 | @footnote{ | |
6213 | The only restriction is that your editor (say @code{ex}), recognizes the | |
6214 | following command-line syntax: | |
10998722 | 6215 | @smallexample |
87885426 | 6216 | ex +@var{number} file |
10998722 | 6217 | @end smallexample |
15387254 EZ |
6218 | The optional numeric value +@var{number} specifies the number of the line in |
6219 | the file where to start editing.}. | |
6220 | By default, it is @file{@value{EDITOR}}, but you can change this | |
10998722 AC |
6221 | by setting the environment variable @code{EDITOR} before using |
6222 | @value{GDBN}. For example, to configure @value{GDBN} to use the | |
6223 | @code{vi} editor, you could use these commands with the @code{sh} shell: | |
6224 | @smallexample | |
87885426 FN |
6225 | EDITOR=/usr/bin/vi |
6226 | export EDITOR | |
15387254 | 6227 | gdb @dots{} |
10998722 | 6228 | @end smallexample |
87885426 | 6229 | or in the @code{csh} shell, |
10998722 | 6230 | @smallexample |
87885426 | 6231 | setenv EDITOR /usr/bin/vi |
15387254 | 6232 | gdb @dots{} |
10998722 | 6233 | @end smallexample |
87885426 | 6234 | |
6d2ebf8b | 6235 | @node Search |
79a6e687 | 6236 | @section Searching Source Files |
15387254 | 6237 | @cindex searching source files |
c906108c SS |
6238 | |
6239 | There are two commands for searching through the current source file for a | |
6240 | regular expression. | |
6241 | ||
6242 | @table @code | |
6243 | @kindex search | |
6244 | @kindex forward-search | |
6245 | @item forward-search @var{regexp} | |
6246 | @itemx search @var{regexp} | |
6247 | The command @samp{forward-search @var{regexp}} checks each line, | |
6248 | starting with the one following the last line listed, for a match for | |
5d161b24 | 6249 | @var{regexp}. It lists the line that is found. You can use the |
c906108c SS |
6250 | synonym @samp{search @var{regexp}} or abbreviate the command name as |
6251 | @code{fo}. | |
6252 | ||
09d4efe1 | 6253 | @kindex reverse-search |
c906108c SS |
6254 | @item reverse-search @var{regexp} |
6255 | The command @samp{reverse-search @var{regexp}} checks each line, starting | |
6256 | with the one before the last line listed and going backward, for a match | |
6257 | for @var{regexp}. It lists the line that is found. You can abbreviate | |
6258 | this command as @code{rev}. | |
6259 | @end table | |
c906108c | 6260 | |
6d2ebf8b | 6261 | @node Source Path |
79a6e687 | 6262 | @section Specifying Source Directories |
c906108c SS |
6263 | |
6264 | @cindex source path | |
6265 | @cindex directories for source files | |
6266 | Executable programs sometimes do not record the directories of the source | |
6267 | files from which they were compiled, just the names. Even when they do, | |
6268 | the directories could be moved between the compilation and your debugging | |
6269 | session. @value{GDBN} has a list of directories to search for source files; | |
6270 | this is called the @dfn{source path}. Each time @value{GDBN} wants a source file, | |
6271 | it tries all the directories in the list, in the order they are present | |
0b66e38c EZ |
6272 | in the list, until it finds a file with the desired name. |
6273 | ||
6274 | For example, suppose an executable references the file | |
6275 | @file{/usr/src/foo-1.0/lib/foo.c}, and our source path is | |
6276 | @file{/mnt/cross}. The file is first looked up literally; if this | |
6277 | fails, @file{/mnt/cross/usr/src/foo-1.0/lib/foo.c} is tried; if this | |
6278 | fails, @file{/mnt/cross/foo.c} is opened; if this fails, an error | |
6279 | message is printed. @value{GDBN} does not look up the parts of the | |
6280 | source file name, such as @file{/mnt/cross/src/foo-1.0/lib/foo.c}. | |
6281 | Likewise, the subdirectories of the source path are not searched: if | |
6282 | the source path is @file{/mnt/cross}, and the binary refers to | |
6283 | @file{foo.c}, @value{GDBN} would not find it under | |
6284 | @file{/mnt/cross/usr/src/foo-1.0/lib}. | |
6285 | ||
6286 | Plain file names, relative file names with leading directories, file | |
6287 | names containing dots, etc.@: are all treated as described above; for | |
6288 | instance, if the source path is @file{/mnt/cross}, and the source file | |
6289 | is recorded as @file{../lib/foo.c}, @value{GDBN} would first try | |
6290 | @file{../lib/foo.c}, then @file{/mnt/cross/../lib/foo.c}, and after | |
6291 | that---@file{/mnt/cross/foo.c}. | |
6292 | ||
6293 | Note that the executable search path is @emph{not} used to locate the | |
cd852561 | 6294 | source files. |
c906108c SS |
6295 | |
6296 | Whenever you reset or rearrange the source path, @value{GDBN} clears out | |
6297 | any information it has cached about where source files are found and where | |
6298 | each line is in the file. | |
6299 | ||
6300 | @kindex directory | |
6301 | @kindex dir | |
d4f3574e SS |
6302 | When you start @value{GDBN}, its source path includes only @samp{cdir} |
6303 | and @samp{cwd}, in that order. | |
c906108c SS |
6304 | To add other directories, use the @code{directory} command. |
6305 | ||
4b505b12 AS |
6306 | The search path is used to find both program source files and @value{GDBN} |
6307 | script files (read using the @samp{-command} option and @samp{source} command). | |
6308 | ||
30daae6c JB |
6309 | In addition to the source path, @value{GDBN} provides a set of commands |
6310 | that manage a list of source path substitution rules. A @dfn{substitution | |
6311 | rule} specifies how to rewrite source directories stored in the program's | |
6312 | debug information in case the sources were moved to a different | |
6313 | directory between compilation and debugging. A rule is made of | |
6314 | two strings, the first specifying what needs to be rewritten in | |
6315 | the path, and the second specifying how it should be rewritten. | |
6316 | In @ref{set substitute-path}, we name these two parts @var{from} and | |
6317 | @var{to} respectively. @value{GDBN} does a simple string replacement | |
6318 | of @var{from} with @var{to} at the start of the directory part of the | |
6319 | source file name, and uses that result instead of the original file | |
6320 | name to look up the sources. | |
6321 | ||
6322 | Using the previous example, suppose the @file{foo-1.0} tree has been | |
6323 | moved from @file{/usr/src} to @file{/mnt/cross}, then you can tell | |
3f94c067 | 6324 | @value{GDBN} to replace @file{/usr/src} in all source path names with |
30daae6c JB |
6325 | @file{/mnt/cross}. The first lookup will then be |
6326 | @file{/mnt/cross/foo-1.0/lib/foo.c} in place of the original location | |
6327 | of @file{/usr/src/foo-1.0/lib/foo.c}. To define a source path | |
6328 | substitution rule, use the @code{set substitute-path} command | |
6329 | (@pxref{set substitute-path}). | |
6330 | ||
6331 | To avoid unexpected substitution results, a rule is applied only if the | |
6332 | @var{from} part of the directory name ends at a directory separator. | |
6333 | For instance, a rule substituting @file{/usr/source} into | |
6334 | @file{/mnt/cross} will be applied to @file{/usr/source/foo-1.0} but | |
6335 | not to @file{/usr/sourceware/foo-2.0}. And because the substitution | |
d3e8051b | 6336 | is applied only at the beginning of the directory name, this rule will |
30daae6c JB |
6337 | not be applied to @file{/root/usr/source/baz.c} either. |
6338 | ||
6339 | In many cases, you can achieve the same result using the @code{directory} | |
6340 | command. However, @code{set substitute-path} can be more efficient in | |
6341 | the case where the sources are organized in a complex tree with multiple | |
6342 | subdirectories. With the @code{directory} command, you need to add each | |
6343 | subdirectory of your project. If you moved the entire tree while | |
6344 | preserving its internal organization, then @code{set substitute-path} | |
6345 | allows you to direct the debugger to all the sources with one single | |
6346 | command. | |
6347 | ||
6348 | @code{set substitute-path} is also more than just a shortcut command. | |
6349 | The source path is only used if the file at the original location no | |
6350 | longer exists. On the other hand, @code{set substitute-path} modifies | |
6351 | the debugger behavior to look at the rewritten location instead. So, if | |
6352 | for any reason a source file that is not relevant to your executable is | |
6353 | located at the original location, a substitution rule is the only | |
3f94c067 | 6354 | method available to point @value{GDBN} at the new location. |
30daae6c | 6355 | |
29b0e8a2 JM |
6356 | @cindex @samp{--with-relocated-sources} |
6357 | @cindex default source path substitution | |
6358 | You can configure a default source path substitution rule by | |
6359 | configuring @value{GDBN} with the | |
6360 | @samp{--with-relocated-sources=@var{dir}} option. The @var{dir} | |
6361 | should be the name of a directory under @value{GDBN}'s configured | |
6362 | prefix (set with @samp{--prefix} or @samp{--exec-prefix}), and | |
6363 | directory names in debug information under @var{dir} will be adjusted | |
6364 | automatically if the installed @value{GDBN} is moved to a new | |
6365 | location. This is useful if @value{GDBN}, libraries or executables | |
6366 | with debug information and corresponding source code are being moved | |
6367 | together. | |
6368 | ||
c906108c SS |
6369 | @table @code |
6370 | @item directory @var{dirname} @dots{} | |
6371 | @item dir @var{dirname} @dots{} | |
6372 | Add directory @var{dirname} to the front of the source path. Several | |
d4f3574e SS |
6373 | directory names may be given to this command, separated by @samp{:} |
6374 | (@samp{;} on MS-DOS and MS-Windows, where @samp{:} usually appears as | |
6375 | part of absolute file names) or | |
c906108c SS |
6376 | whitespace. You may specify a directory that is already in the source |
6377 | path; this moves it forward, so @value{GDBN} searches it sooner. | |
6378 | ||
6379 | @kindex cdir | |
6380 | @kindex cwd | |
41afff9a | 6381 | @vindex $cdir@r{, convenience variable} |
d3e8051b | 6382 | @vindex $cwd@r{, convenience variable} |
c906108c SS |
6383 | @cindex compilation directory |
6384 | @cindex current directory | |
6385 | @cindex working directory | |
6386 | @cindex directory, current | |
6387 | @cindex directory, compilation | |
6388 | You can use the string @samp{$cdir} to refer to the compilation | |
6389 | directory (if one is recorded), and @samp{$cwd} to refer to the current | |
6390 | working directory. @samp{$cwd} is not the same as @samp{.}---the former | |
6391 | tracks the current working directory as it changes during your @value{GDBN} | |
6392 | session, while the latter is immediately expanded to the current | |
6393 | directory at the time you add an entry to the source path. | |
6394 | ||
6395 | @item directory | |
cd852561 | 6396 | Reset the source path to its default value (@samp{$cdir:$cwd} on Unix systems). This requires confirmation. |
c906108c SS |
6397 | |
6398 | @c RET-repeat for @code{directory} is explicitly disabled, but since | |
6399 | @c repeating it would be a no-op we do not say that. (thanks to RMS) | |
6400 | ||
6401 | @item show directories | |
6402 | @kindex show directories | |
6403 | Print the source path: show which directories it contains. | |
30daae6c JB |
6404 | |
6405 | @anchor{set substitute-path} | |
6406 | @item set substitute-path @var{from} @var{to} | |
6407 | @kindex set substitute-path | |
6408 | Define a source path substitution rule, and add it at the end of the | |
6409 | current list of existing substitution rules. If a rule with the same | |
6410 | @var{from} was already defined, then the old rule is also deleted. | |
6411 | ||
6412 | For example, if the file @file{/foo/bar/baz.c} was moved to | |
6413 | @file{/mnt/cross/baz.c}, then the command | |
6414 | ||
6415 | @smallexample | |
6416 | (@value{GDBP}) set substitute-path /usr/src /mnt/cross | |
6417 | @end smallexample | |
6418 | ||
6419 | @noindent | |
6420 | will tell @value{GDBN} to replace @samp{/usr/src} with | |
6421 | @samp{/mnt/cross}, which will allow @value{GDBN} to find the file | |
6422 | @file{baz.c} even though it was moved. | |
6423 | ||
6424 | In the case when more than one substitution rule have been defined, | |
6425 | the rules are evaluated one by one in the order where they have been | |
6426 | defined. The first one matching, if any, is selected to perform | |
6427 | the substitution. | |
6428 | ||
6429 | For instance, if we had entered the following commands: | |
6430 | ||
6431 | @smallexample | |
6432 | (@value{GDBP}) set substitute-path /usr/src/include /mnt/include | |
6433 | (@value{GDBP}) set substitute-path /usr/src /mnt/src | |
6434 | @end smallexample | |
6435 | ||
6436 | @noindent | |
6437 | @value{GDBN} would then rewrite @file{/usr/src/include/defs.h} into | |
6438 | @file{/mnt/include/defs.h} by using the first rule. However, it would | |
6439 | use the second rule to rewrite @file{/usr/src/lib/foo.c} into | |
6440 | @file{/mnt/src/lib/foo.c}. | |
6441 | ||
6442 | ||
6443 | @item unset substitute-path [path] | |
6444 | @kindex unset substitute-path | |
6445 | If a path is specified, search the current list of substitution rules | |
6446 | for a rule that would rewrite that path. Delete that rule if found. | |
6447 | A warning is emitted by the debugger if no rule could be found. | |
6448 | ||
6449 | If no path is specified, then all substitution rules are deleted. | |
6450 | ||
6451 | @item show substitute-path [path] | |
6452 | @kindex show substitute-path | |
6453 | If a path is specified, then print the source path substitution rule | |
6454 | which would rewrite that path, if any. | |
6455 | ||
6456 | If no path is specified, then print all existing source path substitution | |
6457 | rules. | |
6458 | ||
c906108c SS |
6459 | @end table |
6460 | ||
6461 | If your source path is cluttered with directories that are no longer of | |
6462 | interest, @value{GDBN} may sometimes cause confusion by finding the wrong | |
6463 | versions of source. You can correct the situation as follows: | |
6464 | ||
6465 | @enumerate | |
6466 | @item | |
cd852561 | 6467 | Use @code{directory} with no argument to reset the source path to its default value. |
c906108c SS |
6468 | |
6469 | @item | |
6470 | Use @code{directory} with suitable arguments to reinstall the | |
6471 | directories you want in the source path. You can add all the | |
6472 | directories in one command. | |
6473 | @end enumerate | |
6474 | ||
6d2ebf8b | 6475 | @node Machine Code |
79a6e687 | 6476 | @section Source and Machine Code |
15387254 | 6477 | @cindex source line and its code address |
c906108c SS |
6478 | |
6479 | You can use the command @code{info line} to map source lines to program | |
6480 | addresses (and vice versa), and the command @code{disassemble} to display | |
91440f57 HZ |
6481 | a range of addresses as machine instructions. You can use the command |
6482 | @code{set disassemble-next-line} to set whether to disassemble next | |
6483 | source line when execution stops. When run under @sc{gnu} Emacs | |
d4f3574e | 6484 | mode, the @code{info line} command causes the arrow to point to the |
5d161b24 | 6485 | line specified. Also, @code{info line} prints addresses in symbolic form as |
c906108c SS |
6486 | well as hex. |
6487 | ||
6488 | @table @code | |
6489 | @kindex info line | |
6490 | @item info line @var{linespec} | |
6491 | Print the starting and ending addresses of the compiled code for | |
6492 | source line @var{linespec}. You can specify source lines in any of | |
2a25a5ba | 6493 | the ways documented in @ref{Specify Location}. |
c906108c SS |
6494 | @end table |
6495 | ||
6496 | For example, we can use @code{info line} to discover the location of | |
6497 | the object code for the first line of function | |
6498 | @code{m4_changequote}: | |
6499 | ||
d4f3574e SS |
6500 | @c FIXME: I think this example should also show the addresses in |
6501 | @c symbolic form, as they usually would be displayed. | |
c906108c | 6502 | @smallexample |
96a2c332 | 6503 | (@value{GDBP}) info line m4_changequote |
c906108c SS |
6504 | Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350. |
6505 | @end smallexample | |
6506 | ||
6507 | @noindent | |
15387254 | 6508 | @cindex code address and its source line |
c906108c SS |
6509 | We can also inquire (using @code{*@var{addr}} as the form for |
6510 | @var{linespec}) what source line covers a particular address: | |
6511 | @smallexample | |
6512 | (@value{GDBP}) info line *0x63ff | |
6513 | Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404. | |
6514 | @end smallexample | |
6515 | ||
6516 | @cindex @code{$_} and @code{info line} | |
15387254 | 6517 | @cindex @code{x} command, default address |
41afff9a | 6518 | @kindex x@r{(examine), and} info line |
c906108c SS |
6519 | After @code{info line}, the default address for the @code{x} command |
6520 | is changed to the starting address of the line, so that @samp{x/i} is | |
6521 | sufficient to begin examining the machine code (@pxref{Memory, | |
79a6e687 | 6522 | ,Examining Memory}). Also, this address is saved as the value of the |
c906108c | 6523 | convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience |
79a6e687 | 6524 | Variables}). |
c906108c SS |
6525 | |
6526 | @table @code | |
6527 | @kindex disassemble | |
6528 | @cindex assembly instructions | |
6529 | @cindex instructions, assembly | |
6530 | @cindex machine instructions | |
6531 | @cindex listing machine instructions | |
6532 | @item disassemble | |
d14508fe | 6533 | @itemx disassemble /m |
9b117ef3 | 6534 | @itemx disassemble /r |
c906108c | 6535 | This specialized command dumps a range of memory as machine |
d14508fe | 6536 | instructions. It can also print mixed source+disassembly by specifying |
9b117ef3 HZ |
6537 | the @code{/m} modifier and print the raw instructions in hex as well as |
6538 | in symbolic form by specifying the @code{/r}. | |
d14508fe | 6539 | The default memory range is the function surrounding the |
c906108c SS |
6540 | program counter of the selected frame. A single argument to this |
6541 | command is a program counter value; @value{GDBN} dumps the function | |
21a0512e PP |
6542 | surrounding this value. When two arguments are given, they should |
6543 | be separated by a comma, possibly surrounded by whitespace. The | |
6544 | arguments specify a range of addresses (first inclusive, second exclusive) | |
6545 | to dump. In that case, the name of the function is also printed (since | |
6546 | there could be several functions in the given range). | |
6547 | ||
6548 | The argument(s) can be any expression yielding a numeric value, such as | |
6549 | @samp{0x32c4}, @samp{&main+10} or @samp{$pc - 8}. | |
2b28d209 PP |
6550 | |
6551 | If the range of memory being disassembled contains current program counter, | |
6552 | the instruction at that location is shown with a @code{=>} marker. | |
c906108c SS |
6553 | @end table |
6554 | ||
c906108c SS |
6555 | The following example shows the disassembly of a range of addresses of |
6556 | HP PA-RISC 2.0 code: | |
6557 | ||
6558 | @smallexample | |
21a0512e | 6559 | (@value{GDBP}) disas 0x32c4, 0x32e4 |
c906108c | 6560 | Dump of assembler code from 0x32c4 to 0x32e4: |
2b28d209 PP |
6561 | 0x32c4 <main+204>: addil 0,dp |
6562 | 0x32c8 <main+208>: ldw 0x22c(sr0,r1),r26 | |
6563 | 0x32cc <main+212>: ldil 0x3000,r31 | |
6564 | 0x32d0 <main+216>: ble 0x3f8(sr4,r31) | |
6565 | 0x32d4 <main+220>: ldo 0(r31),rp | |
6566 | 0x32d8 <main+224>: addil -0x800,dp | |
6567 | 0x32dc <main+228>: ldo 0x588(r1),r26 | |
6568 | 0x32e0 <main+232>: ldil 0x3000,r31 | |
c906108c SS |
6569 | End of assembler dump. |
6570 | @end smallexample | |
c906108c | 6571 | |
2b28d209 PP |
6572 | Here is an example showing mixed source+assembly for Intel x86, when the |
6573 | program is stopped just after function prologue: | |
d14508fe DE |
6574 | |
6575 | @smallexample | |
6576 | (@value{GDBP}) disas /m main | |
6577 | Dump of assembler code for function main: | |
6578 | 5 @{ | |
9c419145 PP |
6579 | 0x08048330 <+0>: push %ebp |
6580 | 0x08048331 <+1>: mov %esp,%ebp | |
6581 | 0x08048333 <+3>: sub $0x8,%esp | |
6582 | 0x08048336 <+6>: and $0xfffffff0,%esp | |
6583 | 0x08048339 <+9>: sub $0x10,%esp | |
d14508fe DE |
6584 | |
6585 | 6 printf ("Hello.\n"); | |
9c419145 PP |
6586 | => 0x0804833c <+12>: movl $0x8048440,(%esp) |
6587 | 0x08048343 <+19>: call 0x8048284 <puts@@plt> | |
d14508fe DE |
6588 | |
6589 | 7 return 0; | |
6590 | 8 @} | |
9c419145 PP |
6591 | 0x08048348 <+24>: mov $0x0,%eax |
6592 | 0x0804834d <+29>: leave | |
6593 | 0x0804834e <+30>: ret | |
d14508fe DE |
6594 | |
6595 | End of assembler dump. | |
6596 | @end smallexample | |
6597 | ||
c906108c SS |
6598 | Some architectures have more than one commonly-used set of instruction |
6599 | mnemonics or other syntax. | |
6600 | ||
76d17f34 EZ |
6601 | For programs that were dynamically linked and use shared libraries, |
6602 | instructions that call functions or branch to locations in the shared | |
6603 | libraries might show a seemingly bogus location---it's actually a | |
6604 | location of the relocation table. On some architectures, @value{GDBN} | |
6605 | might be able to resolve these to actual function names. | |
6606 | ||
c906108c | 6607 | @table @code |
d4f3574e | 6608 | @kindex set disassembly-flavor |
d4f3574e SS |
6609 | @cindex Intel disassembly flavor |
6610 | @cindex AT&T disassembly flavor | |
6611 | @item set disassembly-flavor @var{instruction-set} | |
c906108c SS |
6612 | Select the instruction set to use when disassembling the |
6613 | program via the @code{disassemble} or @code{x/i} commands. | |
6614 | ||
6615 | Currently this command is only defined for the Intel x86 family. You | |
d4f3574e SS |
6616 | can set @var{instruction-set} to either @code{intel} or @code{att}. |
6617 | The default is @code{att}, the AT&T flavor used by default by Unix | |
6618 | assemblers for x86-based targets. | |
9c16f35a EZ |
6619 | |
6620 | @kindex show disassembly-flavor | |
6621 | @item show disassembly-flavor | |
6622 | Show the current setting of the disassembly flavor. | |
c906108c SS |
6623 | @end table |
6624 | ||
91440f57 HZ |
6625 | @table @code |
6626 | @kindex set disassemble-next-line | |
6627 | @kindex show disassemble-next-line | |
6628 | @item set disassemble-next-line | |
6629 | @itemx show disassemble-next-line | |
32ae1842 EZ |
6630 | Control whether or not @value{GDBN} will disassemble the next source |
6631 | line or instruction when execution stops. If ON, @value{GDBN} will | |
6632 | display disassembly of the next source line when execution of the | |
6633 | program being debugged stops. This is @emph{in addition} to | |
6634 | displaying the source line itself, which @value{GDBN} always does if | |
6635 | possible. If the next source line cannot be displayed for some reason | |
6636 | (e.g., if @value{GDBN} cannot find the source file, or there's no line | |
6637 | info in the debug info), @value{GDBN} will display disassembly of the | |
6638 | next @emph{instruction} instead of showing the next source line. If | |
6639 | AUTO, @value{GDBN} will display disassembly of next instruction only | |
6640 | if the source line cannot be displayed. This setting causes | |
6641 | @value{GDBN} to display some feedback when you step through a function | |
6642 | with no line info or whose source file is unavailable. The default is | |
6643 | OFF, which means never display the disassembly of the next line or | |
6644 | instruction. | |
91440f57 HZ |
6645 | @end table |
6646 | ||
c906108c | 6647 | |
6d2ebf8b | 6648 | @node Data |
c906108c SS |
6649 | @chapter Examining Data |
6650 | ||
6651 | @cindex printing data | |
6652 | @cindex examining data | |
6653 | @kindex print | |
6654 | @kindex inspect | |
6655 | @c "inspect" is not quite a synonym if you are using Epoch, which we do not | |
6656 | @c document because it is nonstandard... Under Epoch it displays in a | |
6657 | @c different window or something like that. | |
6658 | The usual way to examine data in your program is with the @code{print} | |
7a292a7a SS |
6659 | command (abbreviated @code{p}), or its synonym @code{inspect}. It |
6660 | evaluates and prints the value of an expression of the language your | |
6661 | program is written in (@pxref{Languages, ,Using @value{GDBN} with | |
6662 | Different Languages}). | |
c906108c SS |
6663 | |
6664 | @table @code | |
d4f3574e SS |
6665 | @item print @var{expr} |
6666 | @itemx print /@var{f} @var{expr} | |
6667 | @var{expr} is an expression (in the source language). By default the | |
6668 | value of @var{expr} is printed in a format appropriate to its data type; | |
c906108c | 6669 | you can choose a different format by specifying @samp{/@var{f}}, where |
d4f3574e | 6670 | @var{f} is a letter specifying the format; see @ref{Output Formats,,Output |
79a6e687 | 6671 | Formats}. |
c906108c SS |
6672 | |
6673 | @item print | |
6674 | @itemx print /@var{f} | |
15387254 | 6675 | @cindex reprint the last value |
d4f3574e | 6676 | If you omit @var{expr}, @value{GDBN} displays the last value again (from the |
79a6e687 | 6677 | @dfn{value history}; @pxref{Value History, ,Value History}). This allows you to |
c906108c SS |
6678 | conveniently inspect the same value in an alternative format. |
6679 | @end table | |
6680 | ||
6681 | A more low-level way of examining data is with the @code{x} command. | |
6682 | It examines data in memory at a specified address and prints it in a | |
79a6e687 | 6683 | specified format. @xref{Memory, ,Examining Memory}. |
c906108c | 6684 | |
7a292a7a | 6685 | If you are interested in information about types, or about how the |
d4f3574e SS |
6686 | fields of a struct or a class are declared, use the @code{ptype @var{exp}} |
6687 | command rather than @code{print}. @xref{Symbols, ,Examining the Symbol | |
7a292a7a | 6688 | Table}. |
c906108c SS |
6689 | |
6690 | @menu | |
6691 | * Expressions:: Expressions | |
6ba66d6a | 6692 | * Ambiguous Expressions:: Ambiguous Expressions |
c906108c SS |
6693 | * Variables:: Program variables |
6694 | * Arrays:: Artificial arrays | |
6695 | * Output Formats:: Output formats | |
6696 | * Memory:: Examining memory | |
6697 | * Auto Display:: Automatic display | |
6698 | * Print Settings:: Print settings | |
6699 | * Value History:: Value history | |
6700 | * Convenience Vars:: Convenience variables | |
6701 | * Registers:: Registers | |
c906108c | 6702 | * Floating Point Hardware:: Floating point hardware |
53c69bd7 | 6703 | * Vector Unit:: Vector Unit |
721c2651 | 6704 | * OS Information:: Auxiliary data provided by operating system |
29e57380 | 6705 | * Memory Region Attributes:: Memory region attributes |
16d9dec6 | 6706 | * Dump/Restore Files:: Copy between memory and a file |
384ee23f | 6707 | * Core File Generation:: Cause a program dump its core |
a0eb71c5 KB |
6708 | * Character Sets:: Debugging programs that use a different |
6709 | character set than GDB does | |
09d4efe1 | 6710 | * Caching Remote Data:: Data caching for remote targets |
08388c79 | 6711 | * Searching Memory:: Searching memory for a sequence of bytes |
c906108c SS |
6712 | @end menu |
6713 | ||
6d2ebf8b | 6714 | @node Expressions |
c906108c SS |
6715 | @section Expressions |
6716 | ||
6717 | @cindex expressions | |
6718 | @code{print} and many other @value{GDBN} commands accept an expression and | |
6719 | compute its value. Any kind of constant, variable or operator defined | |
6720 | by the programming language you are using is valid in an expression in | |
e2e0bcd1 JB |
6721 | @value{GDBN}. This includes conditional expressions, function calls, |
6722 | casts, and string constants. It also includes preprocessor macros, if | |
6723 | you compiled your program to include this information; see | |
6724 | @ref{Compilation}. | |
c906108c | 6725 | |
15387254 | 6726 | @cindex arrays in expressions |
d4f3574e SS |
6727 | @value{GDBN} supports array constants in expressions input by |
6728 | the user. The syntax is @{@var{element}, @var{element}@dots{}@}. For example, | |
63092375 DJ |
6729 | you can use the command @code{print @{1, 2, 3@}} to create an array |
6730 | of three integers. If you pass an array to a function or assign it | |
6731 | to a program variable, @value{GDBN} copies the array to memory that | |
6732 | is @code{malloc}ed in the target program. | |
c906108c | 6733 | |
c906108c SS |
6734 | Because C is so widespread, most of the expressions shown in examples in |
6735 | this manual are in C. @xref{Languages, , Using @value{GDBN} with Different | |
6736 | Languages}, for information on how to use expressions in other | |
6737 | languages. | |
6738 | ||
6739 | In this section, we discuss operators that you can use in @value{GDBN} | |
6740 | expressions regardless of your programming language. | |
6741 | ||
15387254 | 6742 | @cindex casts, in expressions |
c906108c SS |
6743 | Casts are supported in all languages, not just in C, because it is so |
6744 | useful to cast a number into a pointer in order to examine a structure | |
6745 | at that address in memory. | |
6746 | @c FIXME: casts supported---Mod2 true? | |
c906108c SS |
6747 | |
6748 | @value{GDBN} supports these operators, in addition to those common | |
6749 | to programming languages: | |
6750 | ||
6751 | @table @code | |
6752 | @item @@ | |
6753 | @samp{@@} is a binary operator for treating parts of memory as arrays. | |
79a6e687 | 6754 | @xref{Arrays, ,Artificial Arrays}, for more information. |
c906108c SS |
6755 | |
6756 | @item :: | |
6757 | @samp{::} allows you to specify a variable in terms of the file or | |
79a6e687 | 6758 | function where it is defined. @xref{Variables, ,Program Variables}. |
c906108c SS |
6759 | |
6760 | @cindex @{@var{type}@} | |
6761 | @cindex type casting memory | |
6762 | @cindex memory, viewing as typed object | |
6763 | @cindex casts, to view memory | |
6764 | @item @{@var{type}@} @var{addr} | |
6765 | Refers to an object of type @var{type} stored at address @var{addr} in | |
6766 | memory. @var{addr} may be any expression whose value is an integer or | |
6767 | pointer (but parentheses are required around binary operators, just as in | |
6768 | a cast). This construct is allowed regardless of what kind of data is | |
6769 | normally supposed to reside at @var{addr}. | |
6770 | @end table | |
6771 | ||
6ba66d6a JB |
6772 | @node Ambiguous Expressions |
6773 | @section Ambiguous Expressions | |
6774 | @cindex ambiguous expressions | |
6775 | ||
6776 | Expressions can sometimes contain some ambiguous elements. For instance, | |
6777 | some programming languages (notably Ada, C@t{++} and Objective-C) permit | |
6778 | a single function name to be defined several times, for application in | |
6779 | different contexts. This is called @dfn{overloading}. Another example | |
6780 | involving Ada is generics. A @dfn{generic package} is similar to C@t{++} | |
6781 | templates and is typically instantiated several times, resulting in | |
6782 | the same function name being defined in different contexts. | |
6783 | ||
6784 | In some cases and depending on the language, it is possible to adjust | |
6785 | the expression to remove the ambiguity. For instance in C@t{++}, you | |
6786 | can specify the signature of the function you want to break on, as in | |
6787 | @kbd{break @var{function}(@var{types})}. In Ada, using the fully | |
6788 | qualified name of your function often makes the expression unambiguous | |
6789 | as well. | |
6790 | ||
6791 | When an ambiguity that needs to be resolved is detected, the debugger | |
6792 | has the capability to display a menu of numbered choices for each | |
6793 | possibility, and then waits for the selection with the prompt @samp{>}. | |
6794 | The first option is always @samp{[0] cancel}, and typing @kbd{0 @key{RET}} | |
6795 | aborts the current command. If the command in which the expression was | |
6796 | used allows more than one choice to be selected, the next option in the | |
6797 | menu is @samp{[1] all}, and typing @kbd{1 @key{RET}} selects all possible | |
6798 | choices. | |
6799 | ||
6800 | For example, the following session excerpt shows an attempt to set a | |
6801 | breakpoint at the overloaded symbol @code{String::after}. | |
6802 | We choose three particular definitions of that function name: | |
6803 | ||
6804 | @c FIXME! This is likely to change to show arg type lists, at least | |
6805 | @smallexample | |
6806 | @group | |
6807 | (@value{GDBP}) b String::after | |
6808 | [0] cancel | |
6809 | [1] all | |
6810 | [2] file:String.cc; line number:867 | |
6811 | [3] file:String.cc; line number:860 | |
6812 | [4] file:String.cc; line number:875 | |
6813 | [5] file:String.cc; line number:853 | |
6814 | [6] file:String.cc; line number:846 | |
6815 | [7] file:String.cc; line number:735 | |
6816 | > 2 4 6 | |
6817 | Breakpoint 1 at 0xb26c: file String.cc, line 867. | |
6818 | Breakpoint 2 at 0xb344: file String.cc, line 875. | |
6819 | Breakpoint 3 at 0xafcc: file String.cc, line 846. | |
6820 | Multiple breakpoints were set. | |
6821 | Use the "delete" command to delete unwanted | |
6822 | breakpoints. | |
6823 | (@value{GDBP}) | |
6824 | @end group | |
6825 | @end smallexample | |
6826 | ||
6827 | @table @code | |
6828 | @kindex set multiple-symbols | |
6829 | @item set multiple-symbols @var{mode} | |
6830 | @cindex multiple-symbols menu | |
6831 | ||
6832 | This option allows you to adjust the debugger behavior when an expression | |
6833 | is ambiguous. | |
6834 | ||
6835 | By default, @var{mode} is set to @code{all}. If the command with which | |
6836 | the expression is used allows more than one choice, then @value{GDBN} | |
6837 | automatically selects all possible choices. For instance, inserting | |
6838 | a breakpoint on a function using an ambiguous name results in a breakpoint | |
6839 | inserted on each possible match. However, if a unique choice must be made, | |
6840 | then @value{GDBN} uses the menu to help you disambiguate the expression. | |
6841 | For instance, printing the address of an overloaded function will result | |
6842 | in the use of the menu. | |
6843 | ||
6844 | When @var{mode} is set to @code{ask}, the debugger always uses the menu | |
6845 | when an ambiguity is detected. | |
6846 | ||
6847 | Finally, when @var{mode} is set to @code{cancel}, the debugger reports | |
6848 | an error due to the ambiguity and the command is aborted. | |
6849 | ||
6850 | @kindex show multiple-symbols | |
6851 | @item show multiple-symbols | |
6852 | Show the current value of the @code{multiple-symbols} setting. | |
6853 | @end table | |
6854 | ||
6d2ebf8b | 6855 | @node Variables |
79a6e687 | 6856 | @section Program Variables |
c906108c SS |
6857 | |
6858 | The most common kind of expression to use is the name of a variable | |
6859 | in your program. | |
6860 | ||
6861 | Variables in expressions are understood in the selected stack frame | |
79a6e687 | 6862 | (@pxref{Selection, ,Selecting a Frame}); they must be either: |
c906108c SS |
6863 | |
6864 | @itemize @bullet | |
6865 | @item | |
6866 | global (or file-static) | |
6867 | @end itemize | |
6868 | ||
5d161b24 | 6869 | @noindent or |
c906108c SS |
6870 | |
6871 | @itemize @bullet | |
6872 | @item | |
6873 | visible according to the scope rules of the | |
6874 | programming language from the point of execution in that frame | |
5d161b24 | 6875 | @end itemize |
c906108c SS |
6876 | |
6877 | @noindent This means that in the function | |
6878 | ||
474c8240 | 6879 | @smallexample |
c906108c SS |
6880 | foo (a) |
6881 | int a; | |
6882 | @{ | |
6883 | bar (a); | |
6884 | @{ | |
6885 | int b = test (); | |
6886 | bar (b); | |
6887 | @} | |
6888 | @} | |
474c8240 | 6889 | @end smallexample |
c906108c SS |
6890 | |
6891 | @noindent | |
6892 | you can examine and use the variable @code{a} whenever your program is | |
6893 | executing within the function @code{foo}, but you can only use or | |
6894 | examine the variable @code{b} while your program is executing inside | |
6895 | the block where @code{b} is declared. | |
6896 | ||
6897 | @cindex variable name conflict | |
6898 | There is an exception: you can refer to a variable or function whose | |
6899 | scope is a single source file even if the current execution point is not | |
6900 | in this file. But it is possible to have more than one such variable or | |
6901 | function with the same name (in different source files). If that | |
6902 | happens, referring to that name has unpredictable effects. If you wish, | |
6903 | you can specify a static variable in a particular function or file, | |
15387254 | 6904 | using the colon-colon (@code{::}) notation: |
c906108c | 6905 | |
d4f3574e | 6906 | @cindex colon-colon, context for variables/functions |
12c27660 | 6907 | @ifnotinfo |
c906108c | 6908 | @c info cannot cope with a :: index entry, but why deprive hard copy readers? |
41afff9a | 6909 | @cindex @code{::}, context for variables/functions |
12c27660 | 6910 | @end ifnotinfo |
474c8240 | 6911 | @smallexample |
c906108c SS |
6912 | @var{file}::@var{variable} |
6913 | @var{function}::@var{variable} | |
474c8240 | 6914 | @end smallexample |
c906108c SS |
6915 | |
6916 | @noindent | |
6917 | Here @var{file} or @var{function} is the name of the context for the | |
6918 | static @var{variable}. In the case of file names, you can use quotes to | |
6919 | make sure @value{GDBN} parses the file name as a single word---for example, | |
6920 | to print a global value of @code{x} defined in @file{f2.c}: | |
6921 | ||
474c8240 | 6922 | @smallexample |
c906108c | 6923 | (@value{GDBP}) p 'f2.c'::x |
474c8240 | 6924 | @end smallexample |
c906108c | 6925 | |
b37052ae | 6926 | @cindex C@t{++} scope resolution |
c906108c | 6927 | This use of @samp{::} is very rarely in conflict with the very similar |
b37052ae | 6928 | use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++} |
c906108c SS |
6929 | scope resolution operator in @value{GDBN} expressions. |
6930 | @c FIXME: Um, so what happens in one of those rare cases where it's in | |
6931 | @c conflict?? --mew | |
c906108c SS |
6932 | |
6933 | @cindex wrong values | |
6934 | @cindex variable values, wrong | |
15387254 EZ |
6935 | @cindex function entry/exit, wrong values of variables |
6936 | @cindex optimized code, wrong values of variables | |
c906108c SS |
6937 | @quotation |
6938 | @emph{Warning:} Occasionally, a local variable may appear to have the | |
6939 | wrong value at certain points in a function---just after entry to a new | |
6940 | scope, and just before exit. | |
6941 | @end quotation | |
6942 | You may see this problem when you are stepping by machine instructions. | |
6943 | This is because, on most machines, it takes more than one instruction to | |
6944 | set up a stack frame (including local variable definitions); if you are | |
6945 | stepping by machine instructions, variables may appear to have the wrong | |
6946 | values until the stack frame is completely built. On exit, it usually | |
6947 | also takes more than one machine instruction to destroy a stack frame; | |
6948 | after you begin stepping through that group of instructions, local | |
6949 | variable definitions may be gone. | |
6950 | ||
6951 | This may also happen when the compiler does significant optimizations. | |
6952 | To be sure of always seeing accurate values, turn off all optimization | |
6953 | when compiling. | |
6954 | ||
d4f3574e SS |
6955 | @cindex ``No symbol "foo" in current context'' |
6956 | Another possible effect of compiler optimizations is to optimize | |
6957 | unused variables out of existence, or assign variables to registers (as | |
6958 | opposed to memory addresses). Depending on the support for such cases | |
6959 | offered by the debug info format used by the compiler, @value{GDBN} | |
6960 | might not be able to display values for such local variables. If that | |
6961 | happens, @value{GDBN} will print a message like this: | |
6962 | ||
474c8240 | 6963 | @smallexample |
d4f3574e | 6964 | No symbol "foo" in current context. |
474c8240 | 6965 | @end smallexample |
d4f3574e SS |
6966 | |
6967 | To solve such problems, either recompile without optimizations, or use a | |
6968 | different debug info format, if the compiler supports several such | |
15387254 | 6969 | formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler, |
0179ffac DC |
6970 | usually supports the @option{-gstabs+} option. @option{-gstabs+} |
6971 | produces debug info in a format that is superior to formats such as | |
6972 | COFF. You may be able to use DWARF 2 (@option{-gdwarf-2}), which is also | |
6973 | an effective form for debug info. @xref{Debugging Options,,Options | |
ce9341a1 BW |
6974 | for Debugging Your Program or GCC, gcc.info, Using the @sc{gnu} |
6975 | Compiler Collection (GCC)}. | |
79a6e687 | 6976 | @xref{C, ,C and C@t{++}}, for more information about debug info formats |
15387254 | 6977 | that are best suited to C@t{++} programs. |
d4f3574e | 6978 | |
ab1adacd EZ |
6979 | If you ask to print an object whose contents are unknown to |
6980 | @value{GDBN}, e.g., because its data type is not completely specified | |
6981 | by the debug information, @value{GDBN} will say @samp{<incomplete | |
6982 | type>}. @xref{Symbols, incomplete type}, for more about this. | |
6983 | ||
3a60f64e JK |
6984 | Strings are identified as arrays of @code{char} values without specified |
6985 | signedness. Arrays of either @code{signed char} or @code{unsigned char} get | |
6986 | printed as arrays of 1 byte sized integers. @code{-fsigned-char} or | |
6987 | @code{-funsigned-char} @value{NGCC} options have no effect as @value{GDBN} | |
6988 | defines literal string type @code{"char"} as @code{char} without a sign. | |
6989 | For program code | |
6990 | ||
6991 | @smallexample | |
6992 | char var0[] = "A"; | |
6993 | signed char var1[] = "A"; | |
6994 | @end smallexample | |
6995 | ||
6996 | You get during debugging | |
6997 | @smallexample | |
6998 | (gdb) print var0 | |
6999 | $1 = "A" | |
7000 | (gdb) print var1 | |
7001 | $2 = @{65 'A', 0 '\0'@} | |
7002 | @end smallexample | |
7003 | ||
6d2ebf8b | 7004 | @node Arrays |
79a6e687 | 7005 | @section Artificial Arrays |
c906108c SS |
7006 | |
7007 | @cindex artificial array | |
15387254 | 7008 | @cindex arrays |
41afff9a | 7009 | @kindex @@@r{, referencing memory as an array} |
c906108c SS |
7010 | It is often useful to print out several successive objects of the |
7011 | same type in memory; a section of an array, or an array of | |
7012 | dynamically determined size for which only a pointer exists in the | |
7013 | program. | |
7014 | ||
7015 | You can do this by referring to a contiguous span of memory as an | |
7016 | @dfn{artificial array}, using the binary operator @samp{@@}. The left | |
7017 | operand of @samp{@@} should be the first element of the desired array | |
7018 | and be an individual object. The right operand should be the desired length | |
7019 | of the array. The result is an array value whose elements are all of | |
7020 | the type of the left argument. The first element is actually the left | |
7021 | argument; the second element comes from bytes of memory immediately | |
7022 | following those that hold the first element, and so on. Here is an | |
7023 | example. If a program says | |
7024 | ||
474c8240 | 7025 | @smallexample |
c906108c | 7026 | int *array = (int *) malloc (len * sizeof (int)); |
474c8240 | 7027 | @end smallexample |
c906108c SS |
7028 | |
7029 | @noindent | |
7030 | you can print the contents of @code{array} with | |
7031 | ||
474c8240 | 7032 | @smallexample |
c906108c | 7033 | p *array@@len |
474c8240 | 7034 | @end smallexample |
c906108c SS |
7035 | |
7036 | The left operand of @samp{@@} must reside in memory. Array values made | |
7037 | with @samp{@@} in this way behave just like other arrays in terms of | |
7038 | subscripting, and are coerced to pointers when used in expressions. | |
7039 | Artificial arrays most often appear in expressions via the value history | |
79a6e687 | 7040 | (@pxref{Value History, ,Value History}), after printing one out. |
c906108c SS |
7041 | |
7042 | Another way to create an artificial array is to use a cast. | |
7043 | This re-interprets a value as if it were an array. | |
7044 | The value need not be in memory: | |
474c8240 | 7045 | @smallexample |
c906108c SS |
7046 | (@value{GDBP}) p/x (short[2])0x12345678 |
7047 | $1 = @{0x1234, 0x5678@} | |
474c8240 | 7048 | @end smallexample |
c906108c SS |
7049 | |
7050 | As a convenience, if you leave the array length out (as in | |
c3f6f71d | 7051 | @samp{(@var{type}[])@var{value}}) @value{GDBN} calculates the size to fill |
c906108c | 7052 | the value (as @samp{sizeof(@var{value})/sizeof(@var{type})}: |
474c8240 | 7053 | @smallexample |
c906108c SS |
7054 | (@value{GDBP}) p/x (short[])0x12345678 |
7055 | $2 = @{0x1234, 0x5678@} | |
474c8240 | 7056 | @end smallexample |
c906108c SS |
7057 | |
7058 | Sometimes the artificial array mechanism is not quite enough; in | |
7059 | moderately complex data structures, the elements of interest may not | |
7060 | actually be adjacent---for example, if you are interested in the values | |
7061 | of pointers in an array. One useful work-around in this situation is | |
7062 | to use a convenience variable (@pxref{Convenience Vars, ,Convenience | |
79a6e687 | 7063 | Variables}) as a counter in an expression that prints the first |
c906108c SS |
7064 | interesting value, and then repeat that expression via @key{RET}. For |
7065 | instance, suppose you have an array @code{dtab} of pointers to | |
7066 | structures, and you are interested in the values of a field @code{fv} | |
7067 | in each structure. Here is an example of what you might type: | |
7068 | ||
474c8240 | 7069 | @smallexample |
c906108c SS |
7070 | set $i = 0 |
7071 | p dtab[$i++]->fv | |
7072 | @key{RET} | |
7073 | @key{RET} | |
7074 | @dots{} | |
474c8240 | 7075 | @end smallexample |
c906108c | 7076 | |
6d2ebf8b | 7077 | @node Output Formats |
79a6e687 | 7078 | @section Output Formats |
c906108c SS |
7079 | |
7080 | @cindex formatted output | |
7081 | @cindex output formats | |
7082 | By default, @value{GDBN} prints a value according to its data type. Sometimes | |
7083 | this is not what you want. For example, you might want to print a number | |
7084 | in hex, or a pointer in decimal. Or you might want to view data in memory | |
7085 | at a certain address as a character string or as an instruction. To do | |
7086 | these things, specify an @dfn{output format} when you print a value. | |
7087 | ||
7088 | The simplest use of output formats is to say how to print a value | |
7089 | already computed. This is done by starting the arguments of the | |
7090 | @code{print} command with a slash and a format letter. The format | |
7091 | letters supported are: | |
7092 | ||
7093 | @table @code | |
7094 | @item x | |
7095 | Regard the bits of the value as an integer, and print the integer in | |
7096 | hexadecimal. | |
7097 | ||
7098 | @item d | |
7099 | Print as integer in signed decimal. | |
7100 | ||
7101 | @item u | |
7102 | Print as integer in unsigned decimal. | |
7103 | ||
7104 | @item o | |
7105 | Print as integer in octal. | |
7106 | ||
7107 | @item t | |
7108 | Print as integer in binary. The letter @samp{t} stands for ``two''. | |
7109 | @footnote{@samp{b} cannot be used because these format letters are also | |
7110 | used with the @code{x} command, where @samp{b} stands for ``byte''; | |
79a6e687 | 7111 | see @ref{Memory,,Examining Memory}.} |
c906108c SS |
7112 | |
7113 | @item a | |
7114 | @cindex unknown address, locating | |
3d67e040 | 7115 | @cindex locate address |
c906108c SS |
7116 | Print as an address, both absolute in hexadecimal and as an offset from |
7117 | the nearest preceding symbol. You can use this format used to discover | |
7118 | where (in what function) an unknown address is located: | |
7119 | ||
474c8240 | 7120 | @smallexample |
c906108c SS |
7121 | (@value{GDBP}) p/a 0x54320 |
7122 | $3 = 0x54320 <_initialize_vx+396> | |
474c8240 | 7123 | @end smallexample |
c906108c | 7124 | |
3d67e040 EZ |
7125 | @noindent |
7126 | The command @code{info symbol 0x54320} yields similar results. | |
7127 | @xref{Symbols, info symbol}. | |
7128 | ||
c906108c | 7129 | @item c |
51274035 EZ |
7130 | Regard as an integer and print it as a character constant. This |
7131 | prints both the numerical value and its character representation. The | |
7132 | character representation is replaced with the octal escape @samp{\nnn} | |
7133 | for characters outside the 7-bit @sc{ascii} range. | |
c906108c | 7134 | |
ea37ba09 DJ |
7135 | Without this format, @value{GDBN} displays @code{char}, |
7136 | @w{@code{unsigned char}}, and @w{@code{signed char}} data as character | |
7137 | constants. Single-byte members of vectors are displayed as integer | |
7138 | data. | |
7139 | ||
c906108c SS |
7140 | @item f |
7141 | Regard the bits of the value as a floating point number and print | |
7142 | using typical floating point syntax. | |
ea37ba09 DJ |
7143 | |
7144 | @item s | |
7145 | @cindex printing strings | |
7146 | @cindex printing byte arrays | |
7147 | Regard as a string, if possible. With this format, pointers to single-byte | |
7148 | data are displayed as null-terminated strings and arrays of single-byte data | |
7149 | are displayed as fixed-length strings. Other values are displayed in their | |
7150 | natural types. | |
7151 | ||
7152 | Without this format, @value{GDBN} displays pointers to and arrays of | |
7153 | @code{char}, @w{@code{unsigned char}}, and @w{@code{signed char}} as | |
7154 | strings. Single-byte members of a vector are displayed as an integer | |
7155 | array. | |
a6bac58e TT |
7156 | |
7157 | @item r | |
7158 | @cindex raw printing | |
7159 | Print using the @samp{raw} formatting. By default, @value{GDBN} will | |
7160 | use a type-specific pretty-printer. The @samp{r} format bypasses any | |
7161 | pretty-printer which might exist for the value's type. | |
c906108c SS |
7162 | @end table |
7163 | ||
7164 | For example, to print the program counter in hex (@pxref{Registers}), type | |
7165 | ||
474c8240 | 7166 | @smallexample |
c906108c | 7167 | p/x $pc |
474c8240 | 7168 | @end smallexample |
c906108c SS |
7169 | |
7170 | @noindent | |
7171 | Note that no space is required before the slash; this is because command | |
7172 | names in @value{GDBN} cannot contain a slash. | |
7173 | ||
7174 | To reprint the last value in the value history with a different format, | |
7175 | you can use the @code{print} command with just a format and no | |
7176 | expression. For example, @samp{p/x} reprints the last value in hex. | |
7177 | ||
6d2ebf8b | 7178 | @node Memory |
79a6e687 | 7179 | @section Examining Memory |
c906108c SS |
7180 | |
7181 | You can use the command @code{x} (for ``examine'') to examine memory in | |
7182 | any of several formats, independently of your program's data types. | |
7183 | ||
7184 | @cindex examining memory | |
7185 | @table @code | |
41afff9a | 7186 | @kindex x @r{(examine memory)} |
c906108c SS |
7187 | @item x/@var{nfu} @var{addr} |
7188 | @itemx x @var{addr} | |
7189 | @itemx x | |
7190 | Use the @code{x} command to examine memory. | |
7191 | @end table | |
7192 | ||
7193 | @var{n}, @var{f}, and @var{u} are all optional parameters that specify how | |
7194 | much memory to display and how to format it; @var{addr} is an | |
7195 | expression giving the address where you want to start displaying memory. | |
7196 | If you use defaults for @var{nfu}, you need not type the slash @samp{/}. | |
7197 | Several commands set convenient defaults for @var{addr}. | |
7198 | ||
7199 | @table @r | |
7200 | @item @var{n}, the repeat count | |
7201 | The repeat count is a decimal integer; the default is 1. It specifies | |
7202 | how much memory (counting by units @var{u}) to display. | |
7203 | @c This really is **decimal**; unaffected by 'set radix' as of GDB | |
7204 | @c 4.1.2. | |
7205 | ||
7206 | @item @var{f}, the display format | |
51274035 EZ |
7207 | The display format is one of the formats used by @code{print} |
7208 | (@samp{x}, @samp{d}, @samp{u}, @samp{o}, @samp{t}, @samp{a}, @samp{c}, | |
ea37ba09 DJ |
7209 | @samp{f}, @samp{s}), and in addition @samp{i} (for machine instructions). |
7210 | The default is @samp{x} (hexadecimal) initially. The default changes | |
7211 | each time you use either @code{x} or @code{print}. | |
c906108c SS |
7212 | |
7213 | @item @var{u}, the unit size | |
7214 | The unit size is any of | |
7215 | ||
7216 | @table @code | |
7217 | @item b | |
7218 | Bytes. | |
7219 | @item h | |
7220 | Halfwords (two bytes). | |
7221 | @item w | |
7222 | Words (four bytes). This is the initial default. | |
7223 | @item g | |
7224 | Giant words (eight bytes). | |
7225 | @end table | |
7226 | ||
7227 | Each time you specify a unit size with @code{x}, that size becomes the | |
7228 | default unit the next time you use @code{x}. (For the @samp{s} and | |
7229 | @samp{i} formats, the unit size is ignored and is normally not written.) | |
7230 | ||
7231 | @item @var{addr}, starting display address | |
7232 | @var{addr} is the address where you want @value{GDBN} to begin displaying | |
7233 | memory. The expression need not have a pointer value (though it may); | |
7234 | it is always interpreted as an integer address of a byte of memory. | |
7235 | @xref{Expressions, ,Expressions}, for more information on expressions. The default for | |
7236 | @var{addr} is usually just after the last address examined---but several | |
7237 | other commands also set the default address: @code{info breakpoints} (to | |
7238 | the address of the last breakpoint listed), @code{info line} (to the | |
7239 | starting address of a line), and @code{print} (if you use it to display | |
7240 | a value from memory). | |
7241 | @end table | |
7242 | ||
7243 | For example, @samp{x/3uh 0x54320} is a request to display three halfwords | |
7244 | (@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}), | |
7245 | starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four | |
7246 | words (@samp{w}) of memory above the stack pointer (here, @samp{$sp}; | |
d4f3574e | 7247 | @pxref{Registers, ,Registers}) in hexadecimal (@samp{x}). |
c906108c SS |
7248 | |
7249 | Since the letters indicating unit sizes are all distinct from the | |
7250 | letters specifying output formats, you do not have to remember whether | |
7251 | unit size or format comes first; either order works. The output | |
7252 | specifications @samp{4xw} and @samp{4wx} mean exactly the same thing. | |
7253 | (However, the count @var{n} must come first; @samp{wx4} does not work.) | |
7254 | ||
7255 | Even though the unit size @var{u} is ignored for the formats @samp{s} | |
7256 | and @samp{i}, you might still want to use a count @var{n}; for example, | |
7257 | @samp{3i} specifies that you want to see three machine instructions, | |
a4642986 MR |
7258 | including any operands. For convenience, especially when used with |
7259 | the @code{display} command, the @samp{i} format also prints branch delay | |
7260 | slot instructions, if any, beyond the count specified, which immediately | |
7261 | follow the last instruction that is within the count. The command | |
7262 | @code{disassemble} gives an alternative way of inspecting machine | |
7263 | instructions; see @ref{Machine Code,,Source and Machine Code}. | |
c906108c SS |
7264 | |
7265 | All the defaults for the arguments to @code{x} are designed to make it | |
7266 | easy to continue scanning memory with minimal specifications each time | |
7267 | you use @code{x}. For example, after you have inspected three machine | |
7268 | instructions with @samp{x/3i @var{addr}}, you can inspect the next seven | |
7269 | with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command, | |
7270 | the repeat count @var{n} is used again; the other arguments default as | |
7271 | for successive uses of @code{x}. | |
7272 | ||
2b28d209 PP |
7273 | When examining machine instructions, the instruction at current program |
7274 | counter is shown with a @code{=>} marker. For example: | |
7275 | ||
7276 | @smallexample | |
7277 | (@value{GDBP}) x/5i $pc-6 | |
7278 | 0x804837f <main+11>: mov %esp,%ebp | |
7279 | 0x8048381 <main+13>: push %ecx | |
7280 | 0x8048382 <main+14>: sub $0x4,%esp | |
7281 | => 0x8048385 <main+17>: movl $0x8048460,(%esp) | |
7282 | 0x804838c <main+24>: call 0x80482d4 <puts@@plt> | |
7283 | @end smallexample | |
7284 | ||
c906108c SS |
7285 | @cindex @code{$_}, @code{$__}, and value history |
7286 | The addresses and contents printed by the @code{x} command are not saved | |
7287 | in the value history because there is often too much of them and they | |
7288 | would get in the way. Instead, @value{GDBN} makes these values available for | |
7289 | subsequent use in expressions as values of the convenience variables | |
7290 | @code{$_} and @code{$__}. After an @code{x} command, the last address | |
7291 | examined is available for use in expressions in the convenience variable | |
7292 | @code{$_}. The contents of that address, as examined, are available in | |
7293 | the convenience variable @code{$__}. | |
7294 | ||
7295 | If the @code{x} command has a repeat count, the address and contents saved | |
7296 | are from the last memory unit printed; this is not the same as the last | |
7297 | address printed if several units were printed on the last line of output. | |
7298 | ||
09d4efe1 EZ |
7299 | @cindex remote memory comparison |
7300 | @cindex verify remote memory image | |
7301 | When you are debugging a program running on a remote target machine | |
ea35711c | 7302 | (@pxref{Remote Debugging}), you may wish to verify the program's image in the |
09d4efe1 EZ |
7303 | remote machine's memory against the executable file you downloaded to |
7304 | the target. The @code{compare-sections} command is provided for such | |
7305 | situations. | |
7306 | ||
7307 | @table @code | |
7308 | @kindex compare-sections | |
7309 | @item compare-sections @r{[}@var{section-name}@r{]} | |
7310 | Compare the data of a loadable section @var{section-name} in the | |
7311 | executable file of the program being debugged with the same section in | |
7312 | the remote machine's memory, and report any mismatches. With no | |
7313 | arguments, compares all loadable sections. This command's | |
7314 | availability depends on the target's support for the @code{"qCRC"} | |
7315 | remote request. | |
7316 | @end table | |
7317 | ||
6d2ebf8b | 7318 | @node Auto Display |
79a6e687 | 7319 | @section Automatic Display |
c906108c SS |
7320 | @cindex automatic display |
7321 | @cindex display of expressions | |
7322 | ||
7323 | If you find that you want to print the value of an expression frequently | |
7324 | (to see how it changes), you might want to add it to the @dfn{automatic | |
7325 | display list} so that @value{GDBN} prints its value each time your program stops. | |
7326 | Each expression added to the list is given a number to identify it; | |
7327 | to remove an expression from the list, you specify that number. | |
7328 | The automatic display looks like this: | |
7329 | ||
474c8240 | 7330 | @smallexample |
c906108c SS |
7331 | 2: foo = 38 |
7332 | 3: bar[5] = (struct hack *) 0x3804 | |
474c8240 | 7333 | @end smallexample |
c906108c SS |
7334 | |
7335 | @noindent | |
7336 | This display shows item numbers, expressions and their current values. As with | |
7337 | displays you request manually using @code{x} or @code{print}, you can | |
7338 | specify the output format you prefer; in fact, @code{display} decides | |
ea37ba09 DJ |
7339 | whether to use @code{print} or @code{x} depending your format |
7340 | specification---it uses @code{x} if you specify either the @samp{i} | |
7341 | or @samp{s} format, or a unit size; otherwise it uses @code{print}. | |
c906108c SS |
7342 | |
7343 | @table @code | |
7344 | @kindex display | |
d4f3574e SS |
7345 | @item display @var{expr} |
7346 | Add the expression @var{expr} to the list of expressions to display | |
c906108c SS |
7347 | each time your program stops. @xref{Expressions, ,Expressions}. |
7348 | ||
7349 | @code{display} does not repeat if you press @key{RET} again after using it. | |
7350 | ||
d4f3574e | 7351 | @item display/@var{fmt} @var{expr} |
c906108c | 7352 | For @var{fmt} specifying only a display format and not a size or |
d4f3574e | 7353 | count, add the expression @var{expr} to the auto-display list but |
c906108c | 7354 | arrange to display it each time in the specified format @var{fmt}. |
79a6e687 | 7355 | @xref{Output Formats,,Output Formats}. |
c906108c SS |
7356 | |
7357 | @item display/@var{fmt} @var{addr} | |
7358 | For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a | |
7359 | number of units, add the expression @var{addr} as a memory address to | |
7360 | be examined each time your program stops. Examining means in effect | |
79a6e687 | 7361 | doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining Memory}. |
c906108c SS |
7362 | @end table |
7363 | ||
7364 | For example, @samp{display/i $pc} can be helpful, to see the machine | |
7365 | instruction about to be executed each time execution stops (@samp{$pc} | |
d4f3574e | 7366 | is a common name for the program counter; @pxref{Registers, ,Registers}). |
c906108c SS |
7367 | |
7368 | @table @code | |
7369 | @kindex delete display | |
7370 | @kindex undisplay | |
7371 | @item undisplay @var{dnums}@dots{} | |
7372 | @itemx delete display @var{dnums}@dots{} | |
7373 | Remove item numbers @var{dnums} from the list of expressions to display. | |
7374 | ||
7375 | @code{undisplay} does not repeat if you press @key{RET} after using it. | |
7376 | (Otherwise you would just get the error @samp{No display number @dots{}}.) | |
7377 | ||
7378 | @kindex disable display | |
7379 | @item disable display @var{dnums}@dots{} | |
7380 | Disable the display of item numbers @var{dnums}. A disabled display | |
7381 | item is not printed automatically, but is not forgotten. It may be | |
7382 | enabled again later. | |
7383 | ||
7384 | @kindex enable display | |
7385 | @item enable display @var{dnums}@dots{} | |
7386 | Enable display of item numbers @var{dnums}. It becomes effective once | |
7387 | again in auto display of its expression, until you specify otherwise. | |
7388 | ||
7389 | @item display | |
7390 | Display the current values of the expressions on the list, just as is | |
7391 | done when your program stops. | |
7392 | ||
7393 | @kindex info display | |
7394 | @item info display | |
7395 | Print the list of expressions previously set up to display | |
7396 | automatically, each one with its item number, but without showing the | |
7397 | values. This includes disabled expressions, which are marked as such. | |
7398 | It also includes expressions which would not be displayed right now | |
7399 | because they refer to automatic variables not currently available. | |
7400 | @end table | |
7401 | ||
15387254 | 7402 | @cindex display disabled out of scope |
c906108c SS |
7403 | If a display expression refers to local variables, then it does not make |
7404 | sense outside the lexical context for which it was set up. Such an | |
7405 | expression is disabled when execution enters a context where one of its | |
7406 | variables is not defined. For example, if you give the command | |
7407 | @code{display last_char} while inside a function with an argument | |
7408 | @code{last_char}, @value{GDBN} displays this argument while your program | |
7409 | continues to stop inside that function. When it stops elsewhere---where | |
7410 | there is no variable @code{last_char}---the display is disabled | |
7411 | automatically. The next time your program stops where @code{last_char} | |
7412 | is meaningful, you can enable the display expression once again. | |
7413 | ||
6d2ebf8b | 7414 | @node Print Settings |
79a6e687 | 7415 | @section Print Settings |
c906108c SS |
7416 | |
7417 | @cindex format options | |
7418 | @cindex print settings | |
7419 | @value{GDBN} provides the following ways to control how arrays, structures, | |
7420 | and symbols are printed. | |
7421 | ||
7422 | @noindent | |
7423 | These settings are useful for debugging programs in any language: | |
7424 | ||
7425 | @table @code | |
4644b6e3 | 7426 | @kindex set print |
c906108c SS |
7427 | @item set print address |
7428 | @itemx set print address on | |
4644b6e3 | 7429 | @cindex print/don't print memory addresses |
c906108c SS |
7430 | @value{GDBN} prints memory addresses showing the location of stack |
7431 | traces, structure values, pointer values, breakpoints, and so forth, | |
7432 | even when it also displays the contents of those addresses. The default | |
7433 | is @code{on}. For example, this is what a stack frame display looks like with | |
7434 | @code{set print address on}: | |
7435 | ||
7436 | @smallexample | |
7437 | @group | |
7438 | (@value{GDBP}) f | |
7439 | #0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>") | |
7440 | at input.c:530 | |
7441 | 530 if (lquote != def_lquote) | |
7442 | @end group | |
7443 | @end smallexample | |
7444 | ||
7445 | @item set print address off | |
7446 | Do not print addresses when displaying their contents. For example, | |
7447 | this is the same stack frame displayed with @code{set print address off}: | |
7448 | ||
7449 | @smallexample | |
7450 | @group | |
7451 | (@value{GDBP}) set print addr off | |
7452 | (@value{GDBP}) f | |
7453 | #0 set_quotes (lq="<<", rq=">>") at input.c:530 | |
7454 | 530 if (lquote != def_lquote) | |
7455 | @end group | |
7456 | @end smallexample | |
7457 | ||
7458 | You can use @samp{set print address off} to eliminate all machine | |
7459 | dependent displays from the @value{GDBN} interface. For example, with | |
7460 | @code{print address off}, you should get the same text for backtraces on | |
7461 | all machines---whether or not they involve pointer arguments. | |
7462 | ||
4644b6e3 | 7463 | @kindex show print |
c906108c SS |
7464 | @item show print address |
7465 | Show whether or not addresses are to be printed. | |
7466 | @end table | |
7467 | ||
7468 | When @value{GDBN} prints a symbolic address, it normally prints the | |
7469 | closest earlier symbol plus an offset. If that symbol does not uniquely | |
7470 | identify the address (for example, it is a name whose scope is a single | |
7471 | source file), you may need to clarify. One way to do this is with | |
7472 | @code{info line}, for example @samp{info line *0x4537}. Alternately, | |
7473 | you can set @value{GDBN} to print the source file and line number when | |
7474 | it prints a symbolic address: | |
7475 | ||
7476 | @table @code | |
c906108c | 7477 | @item set print symbol-filename on |
9c16f35a EZ |
7478 | @cindex source file and line of a symbol |
7479 | @cindex symbol, source file and line | |
c906108c SS |
7480 | Tell @value{GDBN} to print the source file name and line number of a |
7481 | symbol in the symbolic form of an address. | |
7482 | ||
7483 | @item set print symbol-filename off | |
7484 | Do not print source file name and line number of a symbol. This is the | |
7485 | default. | |
7486 | ||
c906108c SS |
7487 | @item show print symbol-filename |
7488 | Show whether or not @value{GDBN} will print the source file name and | |
7489 | line number of a symbol in the symbolic form of an address. | |
7490 | @end table | |
7491 | ||
7492 | Another situation where it is helpful to show symbol filenames and line | |
7493 | numbers is when disassembling code; @value{GDBN} shows you the line | |
7494 | number and source file that corresponds to each instruction. | |
7495 | ||
7496 | Also, you may wish to see the symbolic form only if the address being | |
7497 | printed is reasonably close to the closest earlier symbol: | |
7498 | ||
7499 | @table @code | |
c906108c | 7500 | @item set print max-symbolic-offset @var{max-offset} |
4644b6e3 | 7501 | @cindex maximum value for offset of closest symbol |
c906108c SS |
7502 | Tell @value{GDBN} to only display the symbolic form of an address if the |
7503 | offset between the closest earlier symbol and the address is less than | |
5d161b24 | 7504 | @var{max-offset}. The default is 0, which tells @value{GDBN} |
c906108c SS |
7505 | to always print the symbolic form of an address if any symbol precedes it. |
7506 | ||
c906108c SS |
7507 | @item show print max-symbolic-offset |
7508 | Ask how large the maximum offset is that @value{GDBN} prints in a | |
7509 | symbolic address. | |
7510 | @end table | |
7511 | ||
7512 | @cindex wild pointer, interpreting | |
7513 | @cindex pointer, finding referent | |
7514 | If you have a pointer and you are not sure where it points, try | |
7515 | @samp{set print symbol-filename on}. Then you can determine the name | |
7516 | and source file location of the variable where it points, using | |
7517 | @samp{p/a @var{pointer}}. This interprets the address in symbolic form. | |
7518 | For example, here @value{GDBN} shows that a variable @code{ptt} points | |
7519 | at another variable @code{t}, defined in @file{hi2.c}: | |
7520 | ||
474c8240 | 7521 | @smallexample |
c906108c SS |
7522 | (@value{GDBP}) set print symbol-filename on |
7523 | (@value{GDBP}) p/a ptt | |
7524 | $4 = 0xe008 <t in hi2.c> | |
474c8240 | 7525 | @end smallexample |
c906108c SS |
7526 | |
7527 | @quotation | |
7528 | @emph{Warning:} For pointers that point to a local variable, @samp{p/a} | |
7529 | does not show the symbol name and filename of the referent, even with | |
7530 | the appropriate @code{set print} options turned on. | |
7531 | @end quotation | |
7532 | ||
7533 | Other settings control how different kinds of objects are printed: | |
7534 | ||
7535 | @table @code | |
c906108c SS |
7536 | @item set print array |
7537 | @itemx set print array on | |
4644b6e3 | 7538 | @cindex pretty print arrays |
c906108c SS |
7539 | Pretty print arrays. This format is more convenient to read, |
7540 | but uses more space. The default is off. | |
7541 | ||
7542 | @item set print array off | |
7543 | Return to compressed format for arrays. | |
7544 | ||
c906108c SS |
7545 | @item show print array |
7546 | Show whether compressed or pretty format is selected for displaying | |
7547 | arrays. | |
7548 | ||
3c9c013a JB |
7549 | @cindex print array indexes |
7550 | @item set print array-indexes | |
7551 | @itemx set print array-indexes on | |
7552 | Print the index of each element when displaying arrays. May be more | |
7553 | convenient to locate a given element in the array or quickly find the | |
7554 | index of a given element in that printed array. The default is off. | |
7555 | ||
7556 | @item set print array-indexes off | |
7557 | Stop printing element indexes when displaying arrays. | |
7558 | ||
7559 | @item show print array-indexes | |
7560 | Show whether the index of each element is printed when displaying | |
7561 | arrays. | |
7562 | ||
c906108c | 7563 | @item set print elements @var{number-of-elements} |
4644b6e3 | 7564 | @cindex number of array elements to print |
9c16f35a | 7565 | @cindex limit on number of printed array elements |
c906108c SS |
7566 | Set a limit on how many elements of an array @value{GDBN} will print. |
7567 | If @value{GDBN} is printing a large array, it stops printing after it has | |
7568 | printed the number of elements set by the @code{set print elements} command. | |
7569 | This limit also applies to the display of strings. | |
d4f3574e | 7570 | When @value{GDBN} starts, this limit is set to 200. |
c906108c SS |
7571 | Setting @var{number-of-elements} to zero means that the printing is unlimited. |
7572 | ||
c906108c SS |
7573 | @item show print elements |
7574 | Display the number of elements of a large array that @value{GDBN} will print. | |
7575 | If the number is 0, then the printing is unlimited. | |
7576 | ||
b4740add | 7577 | @item set print frame-arguments @var{value} |
a0381d3a | 7578 | @kindex set print frame-arguments |
b4740add JB |
7579 | @cindex printing frame argument values |
7580 | @cindex print all frame argument values | |
7581 | @cindex print frame argument values for scalars only | |
7582 | @cindex do not print frame argument values | |
7583 | This command allows to control how the values of arguments are printed | |
7584 | when the debugger prints a frame (@pxref{Frames}). The possible | |
7585 | values are: | |
7586 | ||
7587 | @table @code | |
7588 | @item all | |
4f5376b2 | 7589 | The values of all arguments are printed. |
b4740add JB |
7590 | |
7591 | @item scalars | |
7592 | Print the value of an argument only if it is a scalar. The value of more | |
7593 | complex arguments such as arrays, structures, unions, etc, is replaced | |
4f5376b2 JB |
7594 | by @code{@dots{}}. This is the default. Here is an example where |
7595 | only scalar arguments are shown: | |
b4740add JB |
7596 | |
7597 | @smallexample | |
7598 | #1 0x08048361 in call_me (i=3, s=@dots{}, ss=0xbf8d508c, u=@dots{}, e=green) | |
7599 | at frame-args.c:23 | |
7600 | @end smallexample | |
7601 | ||
7602 | @item none | |
7603 | None of the argument values are printed. Instead, the value of each argument | |
7604 | is replaced by @code{@dots{}}. In this case, the example above now becomes: | |
7605 | ||
7606 | @smallexample | |
7607 | #1 0x08048361 in call_me (i=@dots{}, s=@dots{}, ss=@dots{}, u=@dots{}, e=@dots{}) | |
7608 | at frame-args.c:23 | |
7609 | @end smallexample | |
7610 | @end table | |
7611 | ||
4f5376b2 JB |
7612 | By default, only scalar arguments are printed. This command can be used |
7613 | to configure the debugger to print the value of all arguments, regardless | |
7614 | of their type. However, it is often advantageous to not print the value | |
7615 | of more complex parameters. For instance, it reduces the amount of | |
7616 | information printed in each frame, making the backtrace more readable. | |
7617 | Also, it improves performance when displaying Ada frames, because | |
7618 | the computation of large arguments can sometimes be CPU-intensive, | |
7619 | especially in large applications. Setting @code{print frame-arguments} | |
7620 | to @code{scalars} (the default) or @code{none} avoids this computation, | |
7621 | thus speeding up the display of each Ada frame. | |
b4740add JB |
7622 | |
7623 | @item show print frame-arguments | |
7624 | Show how the value of arguments should be displayed when printing a frame. | |
7625 | ||
9c16f35a EZ |
7626 | @item set print repeats |
7627 | @cindex repeated array elements | |
7628 | Set the threshold for suppressing display of repeated array | |
d3e8051b | 7629 | elements. When the number of consecutive identical elements of an |
9c16f35a EZ |
7630 | array exceeds the threshold, @value{GDBN} prints the string |
7631 | @code{"<repeats @var{n} times>"}, where @var{n} is the number of | |
7632 | identical repetitions, instead of displaying the identical elements | |
7633 | themselves. Setting the threshold to zero will cause all elements to | |
7634 | be individually printed. The default threshold is 10. | |
7635 | ||
7636 | @item show print repeats | |
7637 | Display the current threshold for printing repeated identical | |
7638 | elements. | |
7639 | ||
c906108c | 7640 | @item set print null-stop |
4644b6e3 | 7641 | @cindex @sc{null} elements in arrays |
c906108c | 7642 | Cause @value{GDBN} to stop printing the characters of an array when the first |
d4f3574e | 7643 | @sc{null} is encountered. This is useful when large arrays actually |
c906108c | 7644 | contain only short strings. |
d4f3574e | 7645 | The default is off. |
c906108c | 7646 | |
9c16f35a EZ |
7647 | @item show print null-stop |
7648 | Show whether @value{GDBN} stops printing an array on the first | |
7649 | @sc{null} character. | |
7650 | ||
c906108c | 7651 | @item set print pretty on |
9c16f35a EZ |
7652 | @cindex print structures in indented form |
7653 | @cindex indentation in structure display | |
5d161b24 | 7654 | Cause @value{GDBN} to print structures in an indented format with one member |
c906108c SS |
7655 | per line, like this: |
7656 | ||
7657 | @smallexample | |
7658 | @group | |
7659 | $1 = @{ | |
7660 | next = 0x0, | |
7661 | flags = @{ | |
7662 | sweet = 1, | |
7663 | sour = 1 | |
7664 | @}, | |
7665 | meat = 0x54 "Pork" | |
7666 | @} | |
7667 | @end group | |
7668 | @end smallexample | |
7669 | ||
7670 | @item set print pretty off | |
7671 | Cause @value{GDBN} to print structures in a compact format, like this: | |
7672 | ||
7673 | @smallexample | |
7674 | @group | |
7675 | $1 = @{next = 0x0, flags = @{sweet = 1, sour = 1@}, \ | |
7676 | meat = 0x54 "Pork"@} | |
7677 | @end group | |
7678 | @end smallexample | |
7679 | ||
7680 | @noindent | |
7681 | This is the default format. | |
7682 | ||
c906108c SS |
7683 | @item show print pretty |
7684 | Show which format @value{GDBN} is using to print structures. | |
7685 | ||
c906108c | 7686 | @item set print sevenbit-strings on |
4644b6e3 EZ |
7687 | @cindex eight-bit characters in strings |
7688 | @cindex octal escapes in strings | |
c906108c SS |
7689 | Print using only seven-bit characters; if this option is set, |
7690 | @value{GDBN} displays any eight-bit characters (in strings or | |
7691 | character values) using the notation @code{\}@var{nnn}. This setting is | |
7692 | best if you are working in English (@sc{ascii}) and you use the | |
7693 | high-order bit of characters as a marker or ``meta'' bit. | |
7694 | ||
7695 | @item set print sevenbit-strings off | |
7696 | Print full eight-bit characters. This allows the use of more | |
7697 | international character sets, and is the default. | |
7698 | ||
c906108c SS |
7699 | @item show print sevenbit-strings |
7700 | Show whether or not @value{GDBN} is printing only seven-bit characters. | |
7701 | ||
c906108c | 7702 | @item set print union on |
4644b6e3 | 7703 | @cindex unions in structures, printing |
9c16f35a EZ |
7704 | Tell @value{GDBN} to print unions which are contained in structures |
7705 | and other unions. This is the default setting. | |
c906108c SS |
7706 | |
7707 | @item set print union off | |
9c16f35a EZ |
7708 | Tell @value{GDBN} not to print unions which are contained in |
7709 | structures and other unions. @value{GDBN} will print @code{"@{...@}"} | |
7710 | instead. | |
c906108c | 7711 | |
c906108c SS |
7712 | @item show print union |
7713 | Ask @value{GDBN} whether or not it will print unions which are contained in | |
9c16f35a | 7714 | structures and other unions. |
c906108c SS |
7715 | |
7716 | For example, given the declarations | |
7717 | ||
7718 | @smallexample | |
7719 | typedef enum @{Tree, Bug@} Species; | |
7720 | typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms; | |
5d161b24 | 7721 | typedef enum @{Caterpillar, Cocoon, Butterfly@} |
c906108c SS |
7722 | Bug_forms; |
7723 | ||
7724 | struct thing @{ | |
7725 | Species it; | |
7726 | union @{ | |
7727 | Tree_forms tree; | |
7728 | Bug_forms bug; | |
7729 | @} form; | |
7730 | @}; | |
7731 | ||
7732 | struct thing foo = @{Tree, @{Acorn@}@}; | |
7733 | @end smallexample | |
7734 | ||
7735 | @noindent | |
7736 | with @code{set print union on} in effect @samp{p foo} would print | |
7737 | ||
7738 | @smallexample | |
7739 | $1 = @{it = Tree, form = @{tree = Acorn, bug = Cocoon@}@} | |
7740 | @end smallexample | |
7741 | ||
7742 | @noindent | |
7743 | and with @code{set print union off} in effect it would print | |
7744 | ||
7745 | @smallexample | |
7746 | $1 = @{it = Tree, form = @{...@}@} | |
7747 | @end smallexample | |
9c16f35a EZ |
7748 | |
7749 | @noindent | |
7750 | @code{set print union} affects programs written in C-like languages | |
7751 | and in Pascal. | |
c906108c SS |
7752 | @end table |
7753 | ||
c906108c SS |
7754 | @need 1000 |
7755 | @noindent | |
b37052ae | 7756 | These settings are of interest when debugging C@t{++} programs: |
c906108c SS |
7757 | |
7758 | @table @code | |
4644b6e3 | 7759 | @cindex demangling C@t{++} names |
c906108c SS |
7760 | @item set print demangle |
7761 | @itemx set print demangle on | |
b37052ae | 7762 | Print C@t{++} names in their source form rather than in the encoded |
c906108c | 7763 | (``mangled'') form passed to the assembler and linker for type-safe |
d4f3574e | 7764 | linkage. The default is on. |
c906108c | 7765 | |
c906108c | 7766 | @item show print demangle |
b37052ae | 7767 | Show whether C@t{++} names are printed in mangled or demangled form. |
c906108c | 7768 | |
c906108c SS |
7769 | @item set print asm-demangle |
7770 | @itemx set print asm-demangle on | |
b37052ae | 7771 | Print C@t{++} names in their source form rather than their mangled form, even |
c906108c SS |
7772 | in assembler code printouts such as instruction disassemblies. |
7773 | The default is off. | |
7774 | ||
c906108c | 7775 | @item show print asm-demangle |
b37052ae | 7776 | Show whether C@t{++} names in assembly listings are printed in mangled |
c906108c SS |
7777 | or demangled form. |
7778 | ||
b37052ae EZ |
7779 | @cindex C@t{++} symbol decoding style |
7780 | @cindex symbol decoding style, C@t{++} | |
a8f24a35 | 7781 | @kindex set demangle-style |
c906108c SS |
7782 | @item set demangle-style @var{style} |
7783 | Choose among several encoding schemes used by different compilers to | |
b37052ae | 7784 | represent C@t{++} names. The choices for @var{style} are currently: |
c906108c SS |
7785 | |
7786 | @table @code | |
7787 | @item auto | |
7788 | Allow @value{GDBN} to choose a decoding style by inspecting your program. | |
7789 | ||
7790 | @item gnu | |
b37052ae | 7791 | Decode based on the @sc{gnu} C@t{++} compiler (@code{g++}) encoding algorithm. |
c906108c | 7792 | This is the default. |
c906108c SS |
7793 | |
7794 | @item hp | |
b37052ae | 7795 | Decode based on the HP ANSI C@t{++} (@code{aCC}) encoding algorithm. |
c906108c SS |
7796 | |
7797 | @item lucid | |
b37052ae | 7798 | Decode based on the Lucid C@t{++} compiler (@code{lcc}) encoding algorithm. |
c906108c SS |
7799 | |
7800 | @item arm | |
b37052ae | 7801 | Decode using the algorithm in the @cite{C@t{++} Annotated Reference Manual}. |
c906108c SS |
7802 | @strong{Warning:} this setting alone is not sufficient to allow |
7803 | debugging @code{cfront}-generated executables. @value{GDBN} would | |
7804 | require further enhancement to permit that. | |
7805 | ||
7806 | @end table | |
7807 | If you omit @var{style}, you will see a list of possible formats. | |
7808 | ||
c906108c | 7809 | @item show demangle-style |
b37052ae | 7810 | Display the encoding style currently in use for decoding C@t{++} symbols. |
c906108c | 7811 | |
c906108c SS |
7812 | @item set print object |
7813 | @itemx set print object on | |
4644b6e3 | 7814 | @cindex derived type of an object, printing |
9c16f35a | 7815 | @cindex display derived types |
c906108c SS |
7816 | When displaying a pointer to an object, identify the @emph{actual} |
7817 | (derived) type of the object rather than the @emph{declared} type, using | |
7818 | the virtual function table. | |
7819 | ||
7820 | @item set print object off | |
7821 | Display only the declared type of objects, without reference to the | |
7822 | virtual function table. This is the default setting. | |
7823 | ||
c906108c SS |
7824 | @item show print object |
7825 | Show whether actual, or declared, object types are displayed. | |
7826 | ||
c906108c SS |
7827 | @item set print static-members |
7828 | @itemx set print static-members on | |
4644b6e3 | 7829 | @cindex static members of C@t{++} objects |
b37052ae | 7830 | Print static members when displaying a C@t{++} object. The default is on. |
c906108c SS |
7831 | |
7832 | @item set print static-members off | |
b37052ae | 7833 | Do not print static members when displaying a C@t{++} object. |
c906108c | 7834 | |
c906108c | 7835 | @item show print static-members |
9c16f35a EZ |
7836 | Show whether C@t{++} static members are printed or not. |
7837 | ||
7838 | @item set print pascal_static-members | |
7839 | @itemx set print pascal_static-members on | |
d3e8051b EZ |
7840 | @cindex static members of Pascal objects |
7841 | @cindex Pascal objects, static members display | |
9c16f35a EZ |
7842 | Print static members when displaying a Pascal object. The default is on. |
7843 | ||
7844 | @item set print pascal_static-members off | |
7845 | Do not print static members when displaying a Pascal object. | |
7846 | ||
7847 | @item show print pascal_static-members | |
7848 | Show whether Pascal static members are printed or not. | |
c906108c SS |
7849 | |
7850 | @c These don't work with HP ANSI C++ yet. | |
c906108c SS |
7851 | @item set print vtbl |
7852 | @itemx set print vtbl on | |
4644b6e3 | 7853 | @cindex pretty print C@t{++} virtual function tables |
9c16f35a EZ |
7854 | @cindex virtual functions (C@t{++}) display |
7855 | @cindex VTBL display | |
b37052ae | 7856 | Pretty print C@t{++} virtual function tables. The default is off. |
c906108c | 7857 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 7858 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
7859 | |
7860 | @item set print vtbl off | |
b37052ae | 7861 | Do not pretty print C@t{++} virtual function tables. |
c906108c | 7862 | |
c906108c | 7863 | @item show print vtbl |
b37052ae | 7864 | Show whether C@t{++} virtual function tables are pretty printed, or not. |
c906108c | 7865 | @end table |
c906108c | 7866 | |
6d2ebf8b | 7867 | @node Value History |
79a6e687 | 7868 | @section Value History |
c906108c SS |
7869 | |
7870 | @cindex value history | |
9c16f35a | 7871 | @cindex history of values printed by @value{GDBN} |
5d161b24 DB |
7872 | Values printed by the @code{print} command are saved in the @value{GDBN} |
7873 | @dfn{value history}. This allows you to refer to them in other expressions. | |
7874 | Values are kept until the symbol table is re-read or discarded | |
7875 | (for example with the @code{file} or @code{symbol-file} commands). | |
7876 | When the symbol table changes, the value history is discarded, | |
7877 | since the values may contain pointers back to the types defined in the | |
c906108c SS |
7878 | symbol table. |
7879 | ||
7880 | @cindex @code{$} | |
7881 | @cindex @code{$$} | |
7882 | @cindex history number | |
7883 | The values printed are given @dfn{history numbers} by which you can | |
7884 | refer to them. These are successive integers starting with one. | |
7885 | @code{print} shows you the history number assigned to a value by | |
7886 | printing @samp{$@var{num} = } before the value; here @var{num} is the | |
7887 | history number. | |
7888 | ||
7889 | To refer to any previous value, use @samp{$} followed by the value's | |
7890 | history number. The way @code{print} labels its output is designed to | |
7891 | remind you of this. Just @code{$} refers to the most recent value in | |
7892 | the history, and @code{$$} refers to the value before that. | |
7893 | @code{$$@var{n}} refers to the @var{n}th value from the end; @code{$$2} | |
7894 | is the value just prior to @code{$$}, @code{$$1} is equivalent to | |
7895 | @code{$$}, and @code{$$0} is equivalent to @code{$}. | |
7896 | ||
7897 | For example, suppose you have just printed a pointer to a structure and | |
7898 | want to see the contents of the structure. It suffices to type | |
7899 | ||
474c8240 | 7900 | @smallexample |
c906108c | 7901 | p *$ |
474c8240 | 7902 | @end smallexample |
c906108c SS |
7903 | |
7904 | If you have a chain of structures where the component @code{next} points | |
7905 | to the next one, you can print the contents of the next one with this: | |
7906 | ||
474c8240 | 7907 | @smallexample |
c906108c | 7908 | p *$.next |
474c8240 | 7909 | @end smallexample |
c906108c SS |
7910 | |
7911 | @noindent | |
7912 | You can print successive links in the chain by repeating this | |
7913 | command---which you can do by just typing @key{RET}. | |
7914 | ||
7915 | Note that the history records values, not expressions. If the value of | |
7916 | @code{x} is 4 and you type these commands: | |
7917 | ||
474c8240 | 7918 | @smallexample |
c906108c SS |
7919 | print x |
7920 | set x=5 | |
474c8240 | 7921 | @end smallexample |
c906108c SS |
7922 | |
7923 | @noindent | |
7924 | then the value recorded in the value history by the @code{print} command | |
7925 | remains 4 even though the value of @code{x} has changed. | |
7926 | ||
7927 | @table @code | |
7928 | @kindex show values | |
7929 | @item show values | |
7930 | Print the last ten values in the value history, with their item numbers. | |
7931 | This is like @samp{p@ $$9} repeated ten times, except that @code{show | |
7932 | values} does not change the history. | |
7933 | ||
7934 | @item show values @var{n} | |
7935 | Print ten history values centered on history item number @var{n}. | |
7936 | ||
7937 | @item show values + | |
7938 | Print ten history values just after the values last printed. If no more | |
7939 | values are available, @code{show values +} produces no display. | |
7940 | @end table | |
7941 | ||
7942 | Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the | |
7943 | same effect as @samp{show values +}. | |
7944 | ||
6d2ebf8b | 7945 | @node Convenience Vars |
79a6e687 | 7946 | @section Convenience Variables |
c906108c SS |
7947 | |
7948 | @cindex convenience variables | |
9c16f35a | 7949 | @cindex user-defined variables |
c906108c SS |
7950 | @value{GDBN} provides @dfn{convenience variables} that you can use within |
7951 | @value{GDBN} to hold on to a value and refer to it later. These variables | |
7952 | exist entirely within @value{GDBN}; they are not part of your program, and | |
7953 | setting a convenience variable has no direct effect on further execution | |
7954 | of your program. That is why you can use them freely. | |
7955 | ||
7956 | Convenience variables are prefixed with @samp{$}. Any name preceded by | |
7957 | @samp{$} can be used for a convenience variable, unless it is one of | |
d4f3574e | 7958 | the predefined machine-specific register names (@pxref{Registers, ,Registers}). |
c906108c | 7959 | (Value history references, in contrast, are @emph{numbers} preceded |
79a6e687 | 7960 | by @samp{$}. @xref{Value History, ,Value History}.) |
c906108c SS |
7961 | |
7962 | You can save a value in a convenience variable with an assignment | |
7963 | expression, just as you would set a variable in your program. | |
7964 | For example: | |
7965 | ||
474c8240 | 7966 | @smallexample |
c906108c | 7967 | set $foo = *object_ptr |
474c8240 | 7968 | @end smallexample |
c906108c SS |
7969 | |
7970 | @noindent | |
7971 | would save in @code{$foo} the value contained in the object pointed to by | |
7972 | @code{object_ptr}. | |
7973 | ||
7974 | Using a convenience variable for the first time creates it, but its | |
7975 | value is @code{void} until you assign a new value. You can alter the | |
7976 | value with another assignment at any time. | |
7977 | ||
7978 | Convenience variables have no fixed types. You can assign a convenience | |
7979 | variable any type of value, including structures and arrays, even if | |
7980 | that variable already has a value of a different type. The convenience | |
7981 | variable, when used as an expression, has the type of its current value. | |
7982 | ||
7983 | @table @code | |
7984 | @kindex show convenience | |
9c16f35a | 7985 | @cindex show all user variables |
c906108c SS |
7986 | @item show convenience |
7987 | Print a list of convenience variables used so far, and their values. | |
d4f3574e | 7988 | Abbreviated @code{show conv}. |
53e5f3cf AS |
7989 | |
7990 | @kindex init-if-undefined | |
7991 | @cindex convenience variables, initializing | |
7992 | @item init-if-undefined $@var{variable} = @var{expression} | |
7993 | Set a convenience variable if it has not already been set. This is useful | |
7994 | for user-defined commands that keep some state. It is similar, in concept, | |
7995 | to using local static variables with initializers in C (except that | |
7996 | convenience variables are global). It can also be used to allow users to | |
7997 | override default values used in a command script. | |
7998 | ||
7999 | If the variable is already defined then the expression is not evaluated so | |
8000 | any side-effects do not occur. | |
c906108c SS |
8001 | @end table |
8002 | ||
8003 | One of the ways to use a convenience variable is as a counter to be | |
8004 | incremented or a pointer to be advanced. For example, to print | |
8005 | a field from successive elements of an array of structures: | |
8006 | ||
474c8240 | 8007 | @smallexample |
c906108c SS |
8008 | set $i = 0 |
8009 | print bar[$i++]->contents | |
474c8240 | 8010 | @end smallexample |
c906108c | 8011 | |
d4f3574e SS |
8012 | @noindent |
8013 | Repeat that command by typing @key{RET}. | |
c906108c SS |
8014 | |
8015 | Some convenience variables are created automatically by @value{GDBN} and given | |
8016 | values likely to be useful. | |
8017 | ||
8018 | @table @code | |
41afff9a | 8019 | @vindex $_@r{, convenience variable} |
c906108c SS |
8020 | @item $_ |
8021 | The variable @code{$_} is automatically set by the @code{x} command to | |
79a6e687 | 8022 | the last address examined (@pxref{Memory, ,Examining Memory}). Other |
c906108c SS |
8023 | commands which provide a default address for @code{x} to examine also |
8024 | set @code{$_} to that address; these commands include @code{info line} | |
8025 | and @code{info breakpoint}. The type of @code{$_} is @code{void *} | |
8026 | except when set by the @code{x} command, in which case it is a pointer | |
8027 | to the type of @code{$__}. | |
8028 | ||
41afff9a | 8029 | @vindex $__@r{, convenience variable} |
c906108c SS |
8030 | @item $__ |
8031 | The variable @code{$__} is automatically set by the @code{x} command | |
8032 | to the value found in the last address examined. Its type is chosen | |
8033 | to match the format in which the data was printed. | |
8034 | ||
8035 | @item $_exitcode | |
41afff9a | 8036 | @vindex $_exitcode@r{, convenience variable} |
c906108c SS |
8037 | The variable @code{$_exitcode} is automatically set to the exit code when |
8038 | the program being debugged terminates. | |
4aa995e1 PA |
8039 | |
8040 | @item $_siginfo | |
8041 | @vindex $_siginfo@r{, convenience variable} | |
ec7e75e7 PP |
8042 | The variable @code{$_siginfo} contains extra signal information |
8043 | (@pxref{extra signal information}). Note that @code{$_siginfo} | |
8044 | could be empty, if the application has not yet received any signals. | |
8045 | For example, it will be empty before you execute the @code{run} command. | |
c906108c SS |
8046 | @end table |
8047 | ||
53a5351d JM |
8048 | On HP-UX systems, if you refer to a function or variable name that |
8049 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
8050 | name first, before it searches for a convenience variable. | |
c906108c | 8051 | |
bc3b79fd TJB |
8052 | @cindex convenience functions |
8053 | @value{GDBN} also supplies some @dfn{convenience functions}. These | |
8054 | have a syntax similar to convenience variables. A convenience | |
8055 | function can be used in an expression just like an ordinary function; | |
8056 | however, a convenience function is implemented internally to | |
8057 | @value{GDBN}. | |
8058 | ||
8059 | @table @code | |
8060 | @item help function | |
8061 | @kindex help function | |
8062 | @cindex show all convenience functions | |
8063 | Print a list of all convenience functions. | |
8064 | @end table | |
8065 | ||
6d2ebf8b | 8066 | @node Registers |
c906108c SS |
8067 | @section Registers |
8068 | ||
8069 | @cindex registers | |
8070 | You can refer to machine register contents, in expressions, as variables | |
8071 | with names starting with @samp{$}. The names of registers are different | |
8072 | for each machine; use @code{info registers} to see the names used on | |
8073 | your machine. | |
8074 | ||
8075 | @table @code | |
8076 | @kindex info registers | |
8077 | @item info registers | |
8078 | Print the names and values of all registers except floating-point | |
c85508ee | 8079 | and vector registers (in the selected stack frame). |
c906108c SS |
8080 | |
8081 | @kindex info all-registers | |
8082 | @cindex floating point registers | |
8083 | @item info all-registers | |
8084 | Print the names and values of all registers, including floating-point | |
c85508ee | 8085 | and vector registers (in the selected stack frame). |
c906108c SS |
8086 | |
8087 | @item info registers @var{regname} @dots{} | |
8088 | Print the @dfn{relativized} value of each specified register @var{regname}. | |
5d161b24 DB |
8089 | As discussed in detail below, register values are normally relative to |
8090 | the selected stack frame. @var{regname} may be any register name valid on | |
c906108c SS |
8091 | the machine you are using, with or without the initial @samp{$}. |
8092 | @end table | |
8093 | ||
e09f16f9 EZ |
8094 | @cindex stack pointer register |
8095 | @cindex program counter register | |
8096 | @cindex process status register | |
8097 | @cindex frame pointer register | |
8098 | @cindex standard registers | |
c906108c SS |
8099 | @value{GDBN} has four ``standard'' register names that are available (in |
8100 | expressions) on most machines---whenever they do not conflict with an | |
8101 | architecture's canonical mnemonics for registers. The register names | |
8102 | @code{$pc} and @code{$sp} are used for the program counter register and | |
8103 | the stack pointer. @code{$fp} is used for a register that contains a | |
8104 | pointer to the current stack frame, and @code{$ps} is used for a | |
8105 | register that contains the processor status. For example, | |
8106 | you could print the program counter in hex with | |
8107 | ||
474c8240 | 8108 | @smallexample |
c906108c | 8109 | p/x $pc |
474c8240 | 8110 | @end smallexample |
c906108c SS |
8111 | |
8112 | @noindent | |
8113 | or print the instruction to be executed next with | |
8114 | ||
474c8240 | 8115 | @smallexample |
c906108c | 8116 | x/i $pc |
474c8240 | 8117 | @end smallexample |
c906108c SS |
8118 | |
8119 | @noindent | |
8120 | or add four to the stack pointer@footnote{This is a way of removing | |
8121 | one word from the stack, on machines where stacks grow downward in | |
8122 | memory (most machines, nowadays). This assumes that the innermost | |
8123 | stack frame is selected; setting @code{$sp} is not allowed when other | |
8124 | stack frames are selected. To pop entire frames off the stack, | |
8125 | regardless of machine architecture, use @code{return}; | |
79a6e687 | 8126 | see @ref{Returning, ,Returning from a Function}.} with |
c906108c | 8127 | |
474c8240 | 8128 | @smallexample |
c906108c | 8129 | set $sp += 4 |
474c8240 | 8130 | @end smallexample |
c906108c SS |
8131 | |
8132 | Whenever possible, these four standard register names are available on | |
8133 | your machine even though the machine has different canonical mnemonics, | |
8134 | so long as there is no conflict. The @code{info registers} command | |
8135 | shows the canonical names. For example, on the SPARC, @code{info | |
8136 | registers} displays the processor status register as @code{$psr} but you | |
d4f3574e SS |
8137 | can also refer to it as @code{$ps}; and on x86-based machines @code{$ps} |
8138 | is an alias for the @sc{eflags} register. | |
c906108c SS |
8139 | |
8140 | @value{GDBN} always considers the contents of an ordinary register as an | |
8141 | integer when the register is examined in this way. Some machines have | |
8142 | special registers which can hold nothing but floating point; these | |
8143 | registers are considered to have floating point values. There is no way | |
8144 | to refer to the contents of an ordinary register as floating point value | |
8145 | (although you can @emph{print} it as a floating point value with | |
8146 | @samp{print/f $@var{regname}}). | |
8147 | ||
8148 | Some registers have distinct ``raw'' and ``virtual'' data formats. This | |
8149 | means that the data format in which the register contents are saved by | |
8150 | the operating system is not the same one that your program normally | |
8151 | sees. For example, the registers of the 68881 floating point | |
8152 | coprocessor are always saved in ``extended'' (raw) format, but all C | |
8153 | programs expect to work with ``double'' (virtual) format. In such | |
5d161b24 | 8154 | cases, @value{GDBN} normally works with the virtual format only (the format |
c906108c SS |
8155 | that makes sense for your program), but the @code{info registers} command |
8156 | prints the data in both formats. | |
8157 | ||
36b80e65 EZ |
8158 | @cindex SSE registers (x86) |
8159 | @cindex MMX registers (x86) | |
8160 | Some machines have special registers whose contents can be interpreted | |
8161 | in several different ways. For example, modern x86-based machines | |
8162 | have SSE and MMX registers that can hold several values packed | |
8163 | together in several different formats. @value{GDBN} refers to such | |
8164 | registers in @code{struct} notation: | |
8165 | ||
8166 | @smallexample | |
8167 | (@value{GDBP}) print $xmm1 | |
8168 | $1 = @{ | |
8169 | v4_float = @{0, 3.43859137e-038, 1.54142831e-044, 1.821688e-044@}, | |
8170 | v2_double = @{9.92129282474342e-303, 2.7585945287983262e-313@}, | |
8171 | v16_int8 = "\000\000\000\000\3706;\001\v\000\000\000\r\000\000", | |
8172 | v8_int16 = @{0, 0, 14072, 315, 11, 0, 13, 0@}, | |
8173 | v4_int32 = @{0, 20657912, 11, 13@}, | |
8174 | v2_int64 = @{88725056443645952, 55834574859@}, | |
8175 | uint128 = 0x0000000d0000000b013b36f800000000 | |
8176 | @} | |
8177 | @end smallexample | |
8178 | ||
8179 | @noindent | |
8180 | To set values of such registers, you need to tell @value{GDBN} which | |
8181 | view of the register you wish to change, as if you were assigning | |
8182 | value to a @code{struct} member: | |
8183 | ||
8184 | @smallexample | |
8185 | (@value{GDBP}) set $xmm1.uint128 = 0x000000000000000000000000FFFFFFFF | |
8186 | @end smallexample | |
8187 | ||
c906108c | 8188 | Normally, register values are relative to the selected stack frame |
79a6e687 | 8189 | (@pxref{Selection, ,Selecting a Frame}). This means that you get the |
c906108c SS |
8190 | value that the register would contain if all stack frames farther in |
8191 | were exited and their saved registers restored. In order to see the | |
8192 | true contents of hardware registers, you must select the innermost | |
8193 | frame (with @samp{frame 0}). | |
8194 | ||
8195 | However, @value{GDBN} must deduce where registers are saved, from the machine | |
8196 | code generated by your compiler. If some registers are not saved, or if | |
8197 | @value{GDBN} is unable to locate the saved registers, the selected stack | |
8198 | frame makes no difference. | |
8199 | ||
6d2ebf8b | 8200 | @node Floating Point Hardware |
79a6e687 | 8201 | @section Floating Point Hardware |
c906108c SS |
8202 | @cindex floating point |
8203 | ||
8204 | Depending on the configuration, @value{GDBN} may be able to give | |
8205 | you more information about the status of the floating point hardware. | |
8206 | ||
8207 | @table @code | |
8208 | @kindex info float | |
8209 | @item info float | |
8210 | Display hardware-dependent information about the floating | |
8211 | point unit. The exact contents and layout vary depending on the | |
8212 | floating point chip. Currently, @samp{info float} is supported on | |
8213 | the ARM and x86 machines. | |
8214 | @end table | |
c906108c | 8215 | |
e76f1f2e AC |
8216 | @node Vector Unit |
8217 | @section Vector Unit | |
8218 | @cindex vector unit | |
8219 | ||
8220 | Depending on the configuration, @value{GDBN} may be able to give you | |
8221 | more information about the status of the vector unit. | |
8222 | ||
8223 | @table @code | |
8224 | @kindex info vector | |
8225 | @item info vector | |
8226 | Display information about the vector unit. The exact contents and | |
8227 | layout vary depending on the hardware. | |
8228 | @end table | |
8229 | ||
721c2651 | 8230 | @node OS Information |
79a6e687 | 8231 | @section Operating System Auxiliary Information |
721c2651 EZ |
8232 | @cindex OS information |
8233 | ||
8234 | @value{GDBN} provides interfaces to useful OS facilities that can help | |
8235 | you debug your program. | |
8236 | ||
8237 | @cindex @code{ptrace} system call | |
8238 | @cindex @code{struct user} contents | |
8239 | When @value{GDBN} runs on a @dfn{Posix system} (such as GNU or Unix | |
8240 | machines), it interfaces with the inferior via the @code{ptrace} | |
8241 | system call. The operating system creates a special sata structure, | |
8242 | called @code{struct user}, for this interface. You can use the | |
8243 | command @code{info udot} to display the contents of this data | |
8244 | structure. | |
8245 | ||
8246 | @table @code | |
8247 | @item info udot | |
8248 | @kindex info udot | |
8249 | Display the contents of the @code{struct user} maintained by the OS | |
8250 | kernel for the program being debugged. @value{GDBN} displays the | |
8251 | contents of @code{struct user} as a list of hex numbers, similar to | |
8252 | the @code{examine} command. | |
8253 | @end table | |
8254 | ||
b383017d RM |
8255 | @cindex auxiliary vector |
8256 | @cindex vector, auxiliary | |
b383017d RM |
8257 | Some operating systems supply an @dfn{auxiliary vector} to programs at |
8258 | startup. This is akin to the arguments and environment that you | |
8259 | specify for a program, but contains a system-dependent variety of | |
8260 | binary values that tell system libraries important details about the | |
8261 | hardware, operating system, and process. Each value's purpose is | |
8262 | identified by an integer tag; the meanings are well-known but system-specific. | |
8263 | Depending on the configuration and operating system facilities, | |
9c16f35a EZ |
8264 | @value{GDBN} may be able to show you this information. For remote |
8265 | targets, this functionality may further depend on the remote stub's | |
427c3a89 DJ |
8266 | support of the @samp{qXfer:auxv:read} packet, see |
8267 | @ref{qXfer auxiliary vector read}. | |
b383017d RM |
8268 | |
8269 | @table @code | |
8270 | @kindex info auxv | |
8271 | @item info auxv | |
8272 | Display the auxiliary vector of the inferior, which can be either a | |
e4937fc1 | 8273 | live process or a core dump file. @value{GDBN} prints each tag value |
b383017d RM |
8274 | numerically, and also shows names and text descriptions for recognized |
8275 | tags. Some values in the vector are numbers, some bit masks, and some | |
e4937fc1 | 8276 | pointers to strings or other data. @value{GDBN} displays each value in the |
b383017d RM |
8277 | most appropriate form for a recognized tag, and in hexadecimal for |
8278 | an unrecognized tag. | |
8279 | @end table | |
8280 | ||
07e059b5 VP |
8281 | On some targets, @value{GDBN} can access operating-system-specific information |
8282 | and display it to user, without interpretation. For remote targets, | |
8283 | this functionality depends on the remote stub's support of the | |
8284 | @samp{qXfer:osdata:read} packet, see @ref{qXfer osdata read}. | |
8285 | ||
8286 | @table @code | |
8287 | @kindex info os processes | |
8288 | @item info os processes | |
8289 | Display the list of processes on the target. For each process, | |
8290 | @value{GDBN} prints the process identifier, the name of the user, and | |
8291 | the command corresponding to the process. | |
8292 | @end table | |
721c2651 | 8293 | |
29e57380 | 8294 | @node Memory Region Attributes |
79a6e687 | 8295 | @section Memory Region Attributes |
29e57380 C |
8296 | @cindex memory region attributes |
8297 | ||
b383017d | 8298 | @dfn{Memory region attributes} allow you to describe special handling |
fd79ecee DJ |
8299 | required by regions of your target's memory. @value{GDBN} uses |
8300 | attributes to determine whether to allow certain types of memory | |
8301 | accesses; whether to use specific width accesses; and whether to cache | |
8302 | target memory. By default the description of memory regions is | |
8303 | fetched from the target (if the current target supports this), but the | |
8304 | user can override the fetched regions. | |
29e57380 C |
8305 | |
8306 | Defined memory regions can be individually enabled and disabled. When a | |
8307 | memory region is disabled, @value{GDBN} uses the default attributes when | |
8308 | accessing memory in that region. Similarly, if no memory regions have | |
8309 | been defined, @value{GDBN} uses the default attributes when accessing | |
8310 | all memory. | |
8311 | ||
b383017d | 8312 | When a memory region is defined, it is given a number to identify it; |
29e57380 C |
8313 | to enable, disable, or remove a memory region, you specify that number. |
8314 | ||
8315 | @table @code | |
8316 | @kindex mem | |
bfac230e | 8317 | @item mem @var{lower} @var{upper} @var{attributes}@dots{} |
09d4efe1 EZ |
8318 | Define a memory region bounded by @var{lower} and @var{upper} with |
8319 | attributes @var{attributes}@dots{}, and add it to the list of regions | |
8320 | monitored by @value{GDBN}. Note that @var{upper} == 0 is a special | |
d3e8051b | 8321 | case: it is treated as the target's maximum memory address. |
bfac230e | 8322 | (0xffff on 16 bit targets, 0xffffffff on 32 bit targets, etc.) |
29e57380 | 8323 | |
fd79ecee DJ |
8324 | @item mem auto |
8325 | Discard any user changes to the memory regions and use target-supplied | |
8326 | regions, if available, or no regions if the target does not support. | |
8327 | ||
29e57380 C |
8328 | @kindex delete mem |
8329 | @item delete mem @var{nums}@dots{} | |
09d4efe1 EZ |
8330 | Remove memory regions @var{nums}@dots{} from the list of regions |
8331 | monitored by @value{GDBN}. | |
29e57380 C |
8332 | |
8333 | @kindex disable mem | |
8334 | @item disable mem @var{nums}@dots{} | |
09d4efe1 | 8335 | Disable monitoring of memory regions @var{nums}@dots{}. |
b383017d | 8336 | A disabled memory region is not forgotten. |
29e57380 C |
8337 | It may be enabled again later. |
8338 | ||
8339 | @kindex enable mem | |
8340 | @item enable mem @var{nums}@dots{} | |
09d4efe1 | 8341 | Enable monitoring of memory regions @var{nums}@dots{}. |
29e57380 C |
8342 | |
8343 | @kindex info mem | |
8344 | @item info mem | |
8345 | Print a table of all defined memory regions, with the following columns | |
09d4efe1 | 8346 | for each region: |
29e57380 C |
8347 | |
8348 | @table @emph | |
8349 | @item Memory Region Number | |
8350 | @item Enabled or Disabled. | |
b383017d | 8351 | Enabled memory regions are marked with @samp{y}. |
29e57380 C |
8352 | Disabled memory regions are marked with @samp{n}. |
8353 | ||
8354 | @item Lo Address | |
8355 | The address defining the inclusive lower bound of the memory region. | |
8356 | ||
8357 | @item Hi Address | |
8358 | The address defining the exclusive upper bound of the memory region. | |
8359 | ||
8360 | @item Attributes | |
8361 | The list of attributes set for this memory region. | |
8362 | @end table | |
8363 | @end table | |
8364 | ||
8365 | ||
8366 | @subsection Attributes | |
8367 | ||
b383017d | 8368 | @subsubsection Memory Access Mode |
29e57380 C |
8369 | The access mode attributes set whether @value{GDBN} may make read or |
8370 | write accesses to a memory region. | |
8371 | ||
8372 | While these attributes prevent @value{GDBN} from performing invalid | |
8373 | memory accesses, they do nothing to prevent the target system, I/O DMA, | |
359df76b | 8374 | etc.@: from accessing memory. |
29e57380 C |
8375 | |
8376 | @table @code | |
8377 | @item ro | |
8378 | Memory is read only. | |
8379 | @item wo | |
8380 | Memory is write only. | |
8381 | @item rw | |
6ca652b0 | 8382 | Memory is read/write. This is the default. |
29e57380 C |
8383 | @end table |
8384 | ||
8385 | @subsubsection Memory Access Size | |
d3e8051b | 8386 | The access size attribute tells @value{GDBN} to use specific sized |
29e57380 C |
8387 | accesses in the memory region. Often memory mapped device registers |
8388 | require specific sized accesses. If no access size attribute is | |
8389 | specified, @value{GDBN} may use accesses of any size. | |
8390 | ||
8391 | @table @code | |
8392 | @item 8 | |
8393 | Use 8 bit memory accesses. | |
8394 | @item 16 | |
8395 | Use 16 bit memory accesses. | |
8396 | @item 32 | |
8397 | Use 32 bit memory accesses. | |
8398 | @item 64 | |
8399 | Use 64 bit memory accesses. | |
8400 | @end table | |
8401 | ||
8402 | @c @subsubsection Hardware/Software Breakpoints | |
8403 | @c The hardware/software breakpoint attributes set whether @value{GDBN} | |
8404 | @c will use hardware or software breakpoints for the internal breakpoints | |
8405 | @c used by the step, next, finish, until, etc. commands. | |
8406 | @c | |
8407 | @c @table @code | |
8408 | @c @item hwbreak | |
b383017d | 8409 | @c Always use hardware breakpoints |
29e57380 C |
8410 | @c @item swbreak (default) |
8411 | @c @end table | |
8412 | ||
8413 | @subsubsection Data Cache | |
8414 | The data cache attributes set whether @value{GDBN} will cache target | |
8415 | memory. While this generally improves performance by reducing debug | |
8416 | protocol overhead, it can lead to incorrect results because @value{GDBN} | |
8417 | does not know about volatile variables or memory mapped device | |
8418 | registers. | |
8419 | ||
8420 | @table @code | |
8421 | @item cache | |
b383017d | 8422 | Enable @value{GDBN} to cache target memory. |
6ca652b0 EZ |
8423 | @item nocache |
8424 | Disable @value{GDBN} from caching target memory. This is the default. | |
29e57380 C |
8425 | @end table |
8426 | ||
4b5752d0 VP |
8427 | @subsection Memory Access Checking |
8428 | @value{GDBN} can be instructed to refuse accesses to memory that is | |
8429 | not explicitly described. This can be useful if accessing such | |
8430 | regions has undesired effects for a specific target, or to provide | |
8431 | better error checking. The following commands control this behaviour. | |
8432 | ||
8433 | @table @code | |
8434 | @kindex set mem inaccessible-by-default | |
8435 | @item set mem inaccessible-by-default [on|off] | |
8436 | If @code{on} is specified, make @value{GDBN} treat memory not | |
8437 | explicitly described by the memory ranges as non-existent and refuse accesses | |
8438 | to such memory. The checks are only performed if there's at least one | |
8439 | memory range defined. If @code{off} is specified, make @value{GDBN} | |
8440 | treat the memory not explicitly described by the memory ranges as RAM. | |
56cf5405 | 8441 | The default value is @code{on}. |
4b5752d0 VP |
8442 | @kindex show mem inaccessible-by-default |
8443 | @item show mem inaccessible-by-default | |
8444 | Show the current handling of accesses to unknown memory. | |
8445 | @end table | |
8446 | ||
8447 | ||
29e57380 | 8448 | @c @subsubsection Memory Write Verification |
b383017d | 8449 | @c The memory write verification attributes set whether @value{GDBN} |
29e57380 C |
8450 | @c will re-reads data after each write to verify the write was successful. |
8451 | @c | |
8452 | @c @table @code | |
8453 | @c @item verify | |
8454 | @c @item noverify (default) | |
8455 | @c @end table | |
8456 | ||
16d9dec6 | 8457 | @node Dump/Restore Files |
79a6e687 | 8458 | @section Copy Between Memory and a File |
16d9dec6 MS |
8459 | @cindex dump/restore files |
8460 | @cindex append data to a file | |
8461 | @cindex dump data to a file | |
8462 | @cindex restore data from a file | |
16d9dec6 | 8463 | |
df5215a6 JB |
8464 | You can use the commands @code{dump}, @code{append}, and |
8465 | @code{restore} to copy data between target memory and a file. The | |
8466 | @code{dump} and @code{append} commands write data to a file, and the | |
8467 | @code{restore} command reads data from a file back into the inferior's | |
8468 | memory. Files may be in binary, Motorola S-record, Intel hex, or | |
8469 | Tektronix Hex format; however, @value{GDBN} can only append to binary | |
8470 | files. | |
8471 | ||
8472 | @table @code | |
8473 | ||
8474 | @kindex dump | |
8475 | @item dump @r{[}@var{format}@r{]} memory @var{filename} @var{start_addr} @var{end_addr} | |
8476 | @itemx dump @r{[}@var{format}@r{]} value @var{filename} @var{expr} | |
8477 | Dump the contents of memory from @var{start_addr} to @var{end_addr}, | |
8478 | or the value of @var{expr}, to @var{filename} in the given format. | |
16d9dec6 | 8479 | |
df5215a6 | 8480 | The @var{format} parameter may be any one of: |
16d9dec6 | 8481 | @table @code |
df5215a6 JB |
8482 | @item binary |
8483 | Raw binary form. | |
8484 | @item ihex | |
8485 | Intel hex format. | |
8486 | @item srec | |
8487 | Motorola S-record format. | |
8488 | @item tekhex | |
8489 | Tektronix Hex format. | |
8490 | @end table | |
8491 | ||
8492 | @value{GDBN} uses the same definitions of these formats as the | |
8493 | @sc{gnu} binary utilities, like @samp{objdump} and @samp{objcopy}. If | |
8494 | @var{format} is omitted, @value{GDBN} dumps the data in raw binary | |
8495 | form. | |
8496 | ||
8497 | @kindex append | |
8498 | @item append @r{[}binary@r{]} memory @var{filename} @var{start_addr} @var{end_addr} | |
8499 | @itemx append @r{[}binary@r{]} value @var{filename} @var{expr} | |
8500 | Append the contents of memory from @var{start_addr} to @var{end_addr}, | |
09d4efe1 | 8501 | or the value of @var{expr}, to the file @var{filename}, in raw binary form. |
df5215a6 JB |
8502 | (@value{GDBN} can only append data to files in raw binary form.) |
8503 | ||
8504 | @kindex restore | |
8505 | @item restore @var{filename} @r{[}binary@r{]} @var{bias} @var{start} @var{end} | |
8506 | Restore the contents of file @var{filename} into memory. The | |
8507 | @code{restore} command can automatically recognize any known @sc{bfd} | |
8508 | file format, except for raw binary. To restore a raw binary file you | |
8509 | must specify the optional keyword @code{binary} after the filename. | |
16d9dec6 | 8510 | |
b383017d | 8511 | If @var{bias} is non-zero, its value will be added to the addresses |
16d9dec6 MS |
8512 | contained in the file. Binary files always start at address zero, so |
8513 | they will be restored at address @var{bias}. Other bfd files have | |
8514 | a built-in location; they will be restored at offset @var{bias} | |
8515 | from that location. | |
8516 | ||
8517 | If @var{start} and/or @var{end} are non-zero, then only data between | |
8518 | file offset @var{start} and file offset @var{end} will be restored. | |
b383017d | 8519 | These offsets are relative to the addresses in the file, before |
16d9dec6 MS |
8520 | the @var{bias} argument is applied. |
8521 | ||
8522 | @end table | |
8523 | ||
384ee23f EZ |
8524 | @node Core File Generation |
8525 | @section How to Produce a Core File from Your Program | |
8526 | @cindex dump core from inferior | |
8527 | ||
8528 | A @dfn{core file} or @dfn{core dump} is a file that records the memory | |
8529 | image of a running process and its process status (register values | |
8530 | etc.). Its primary use is post-mortem debugging of a program that | |
8531 | crashed while it ran outside a debugger. A program that crashes | |
8532 | automatically produces a core file, unless this feature is disabled by | |
8533 | the user. @xref{Files}, for information on invoking @value{GDBN} in | |
8534 | the post-mortem debugging mode. | |
8535 | ||
8536 | Occasionally, you may wish to produce a core file of the program you | |
8537 | are debugging in order to preserve a snapshot of its state. | |
8538 | @value{GDBN} has a special command for that. | |
8539 | ||
8540 | @table @code | |
8541 | @kindex gcore | |
8542 | @kindex generate-core-file | |
8543 | @item generate-core-file [@var{file}] | |
8544 | @itemx gcore [@var{file}] | |
8545 | Produce a core dump of the inferior process. The optional argument | |
8546 | @var{file} specifies the file name where to put the core dump. If not | |
8547 | specified, the file name defaults to @file{core.@var{pid}}, where | |
8548 | @var{pid} is the inferior process ID. | |
8549 | ||
8550 | Note that this command is implemented only for some systems (as of | |
8551 | this writing, @sc{gnu}/Linux, FreeBSD, Solaris, Unixware, and S390). | |
8552 | @end table | |
8553 | ||
a0eb71c5 KB |
8554 | @node Character Sets |
8555 | @section Character Sets | |
8556 | @cindex character sets | |
8557 | @cindex charset | |
8558 | @cindex translating between character sets | |
8559 | @cindex host character set | |
8560 | @cindex target character set | |
8561 | ||
8562 | If the program you are debugging uses a different character set to | |
8563 | represent characters and strings than the one @value{GDBN} uses itself, | |
8564 | @value{GDBN} can automatically translate between the character sets for | |
8565 | you. The character set @value{GDBN} uses we call the @dfn{host | |
8566 | character set}; the one the inferior program uses we call the | |
8567 | @dfn{target character set}. | |
8568 | ||
8569 | For example, if you are running @value{GDBN} on a @sc{gnu}/Linux system, which | |
8570 | uses the ISO Latin 1 character set, but you are using @value{GDBN}'s | |
ea35711c | 8571 | remote protocol (@pxref{Remote Debugging}) to debug a program |
a0eb71c5 KB |
8572 | running on an IBM mainframe, which uses the @sc{ebcdic} character set, |
8573 | then the host character set is Latin-1, and the target character set is | |
8574 | @sc{ebcdic}. If you give @value{GDBN} the command @code{set | |
e33d66ec | 8575 | target-charset EBCDIC-US}, then @value{GDBN} translates between |
a0eb71c5 KB |
8576 | @sc{ebcdic} and Latin 1 as you print character or string values, or use |
8577 | character and string literals in expressions. | |
8578 | ||
8579 | @value{GDBN} has no way to automatically recognize which character set | |
8580 | the inferior program uses; you must tell it, using the @code{set | |
8581 | target-charset} command, described below. | |
8582 | ||
8583 | Here are the commands for controlling @value{GDBN}'s character set | |
8584 | support: | |
8585 | ||
8586 | @table @code | |
8587 | @item set target-charset @var{charset} | |
8588 | @kindex set target-charset | |
10af6951 EZ |
8589 | Set the current target character set to @var{charset}. To display the |
8590 | list of supported target character sets, type | |
8591 | @kbd{@w{set target-charset @key{TAB}@key{TAB}}}. | |
a0eb71c5 | 8592 | |
a0eb71c5 KB |
8593 | @item set host-charset @var{charset} |
8594 | @kindex set host-charset | |
8595 | Set the current host character set to @var{charset}. | |
8596 | ||
8597 | By default, @value{GDBN} uses a host character set appropriate to the | |
8598 | system it is running on; you can override that default using the | |
732f6a93 TT |
8599 | @code{set host-charset} command. On some systems, @value{GDBN} cannot |
8600 | automatically determine the appropriate host character set. In this | |
8601 | case, @value{GDBN} uses @samp{UTF-8}. | |
a0eb71c5 KB |
8602 | |
8603 | @value{GDBN} can only use certain character sets as its host character | |
10af6951 EZ |
8604 | set. If you type @kbd{@w{set target-charset @key{TAB}@key{TAB}}}, |
8605 | @value{GDBN} will list the host character sets it supports. | |
a0eb71c5 KB |
8606 | |
8607 | @item set charset @var{charset} | |
8608 | @kindex set charset | |
e33d66ec | 8609 | Set the current host and target character sets to @var{charset}. As |
10af6951 EZ |
8610 | above, if you type @kbd{@w{set charset @key{TAB}@key{TAB}}}, |
8611 | @value{GDBN} will list the names of the character sets that can be used | |
e33d66ec EZ |
8612 | for both host and target. |
8613 | ||
a0eb71c5 | 8614 | @item show charset |
a0eb71c5 | 8615 | @kindex show charset |
10af6951 | 8616 | Show the names of the current host and target character sets. |
e33d66ec | 8617 | |
10af6951 | 8618 | @item show host-charset |
a0eb71c5 | 8619 | @kindex show host-charset |
10af6951 | 8620 | Show the name of the current host character set. |
e33d66ec | 8621 | |
10af6951 | 8622 | @item show target-charset |
a0eb71c5 | 8623 | @kindex show target-charset |
10af6951 | 8624 | Show the name of the current target character set. |
a0eb71c5 | 8625 | |
10af6951 EZ |
8626 | @item set target-wide-charset @var{charset} |
8627 | @kindex set target-wide-charset | |
8628 | Set the current target's wide character set to @var{charset}. This is | |
8629 | the character set used by the target's @code{wchar_t} type. To | |
8630 | display the list of supported wide character sets, type | |
8631 | @kbd{@w{set target-wide-charset @key{TAB}@key{TAB}}}. | |
8632 | ||
8633 | @item show target-wide-charset | |
8634 | @kindex show target-wide-charset | |
8635 | Show the name of the current target's wide character set. | |
a0eb71c5 KB |
8636 | @end table |
8637 | ||
a0eb71c5 KB |
8638 | Here is an example of @value{GDBN}'s character set support in action. |
8639 | Assume that the following source code has been placed in the file | |
8640 | @file{charset-test.c}: | |
8641 | ||
8642 | @smallexample | |
8643 | #include <stdio.h> | |
8644 | ||
8645 | char ascii_hello[] | |
8646 | = @{72, 101, 108, 108, 111, 44, 32, 119, | |
8647 | 111, 114, 108, 100, 33, 10, 0@}; | |
8648 | char ibm1047_hello[] | |
8649 | = @{200, 133, 147, 147, 150, 107, 64, 166, | |
8650 | 150, 153, 147, 132, 90, 37, 0@}; | |
8651 | ||
8652 | main () | |
8653 | @{ | |
8654 | printf ("Hello, world!\n"); | |
8655 | @} | |
10998722 | 8656 | @end smallexample |
a0eb71c5 KB |
8657 | |
8658 | In this program, @code{ascii_hello} and @code{ibm1047_hello} are arrays | |
8659 | containing the string @samp{Hello, world!} followed by a newline, | |
8660 | encoded in the @sc{ascii} and @sc{ibm1047} character sets. | |
8661 | ||
8662 | We compile the program, and invoke the debugger on it: | |
8663 | ||
8664 | @smallexample | |
8665 | $ gcc -g charset-test.c -o charset-test | |
8666 | $ gdb -nw charset-test | |
8667 | GNU gdb 2001-12-19-cvs | |
8668 | Copyright 2001 Free Software Foundation, Inc. | |
8669 | @dots{} | |
f7dc1244 | 8670 | (@value{GDBP}) |
10998722 | 8671 | @end smallexample |
a0eb71c5 KB |
8672 | |
8673 | We can use the @code{show charset} command to see what character sets | |
8674 | @value{GDBN} is currently using to interpret and display characters and | |
8675 | strings: | |
8676 | ||
8677 | @smallexample | |
f7dc1244 | 8678 | (@value{GDBP}) show charset |
e33d66ec | 8679 | The current host and target character set is `ISO-8859-1'. |
f7dc1244 | 8680 | (@value{GDBP}) |
10998722 | 8681 | @end smallexample |
a0eb71c5 KB |
8682 | |
8683 | For the sake of printing this manual, let's use @sc{ascii} as our | |
8684 | initial character set: | |
8685 | @smallexample | |
f7dc1244 EZ |
8686 | (@value{GDBP}) set charset ASCII |
8687 | (@value{GDBP}) show charset | |
e33d66ec | 8688 | The current host and target character set is `ASCII'. |
f7dc1244 | 8689 | (@value{GDBP}) |
10998722 | 8690 | @end smallexample |
a0eb71c5 KB |
8691 | |
8692 | Let's assume that @sc{ascii} is indeed the correct character set for our | |
8693 | host system --- in other words, let's assume that if @value{GDBN} prints | |
8694 | characters using the @sc{ascii} character set, our terminal will display | |
8695 | them properly. Since our current target character set is also | |
8696 | @sc{ascii}, the contents of @code{ascii_hello} print legibly: | |
8697 | ||
8698 | @smallexample | |
f7dc1244 | 8699 | (@value{GDBP}) print ascii_hello |
a0eb71c5 | 8700 | $1 = 0x401698 "Hello, world!\n" |
f7dc1244 | 8701 | (@value{GDBP}) print ascii_hello[0] |
a0eb71c5 | 8702 | $2 = 72 'H' |
f7dc1244 | 8703 | (@value{GDBP}) |
10998722 | 8704 | @end smallexample |
a0eb71c5 KB |
8705 | |
8706 | @value{GDBN} uses the target character set for character and string | |
8707 | literals you use in expressions: | |
8708 | ||
8709 | @smallexample | |
f7dc1244 | 8710 | (@value{GDBP}) print '+' |
a0eb71c5 | 8711 | $3 = 43 '+' |
f7dc1244 | 8712 | (@value{GDBP}) |
10998722 | 8713 | @end smallexample |
a0eb71c5 KB |
8714 | |
8715 | The @sc{ascii} character set uses the number 43 to encode the @samp{+} | |
8716 | character. | |
8717 | ||
8718 | @value{GDBN} relies on the user to tell it which character set the | |
8719 | target program uses. If we print @code{ibm1047_hello} while our target | |
8720 | character set is still @sc{ascii}, we get jibberish: | |
8721 | ||
8722 | @smallexample | |
f7dc1244 | 8723 | (@value{GDBP}) print ibm1047_hello |
a0eb71c5 | 8724 | $4 = 0x4016a8 "\310\205\223\223\226k@@\246\226\231\223\204Z%" |
f7dc1244 | 8725 | (@value{GDBP}) print ibm1047_hello[0] |
a0eb71c5 | 8726 | $5 = 200 '\310' |
f7dc1244 | 8727 | (@value{GDBP}) |
10998722 | 8728 | @end smallexample |
a0eb71c5 | 8729 | |
e33d66ec | 8730 | If we invoke the @code{set target-charset} followed by @key{TAB}@key{TAB}, |
a0eb71c5 KB |
8731 | @value{GDBN} tells us the character sets it supports: |
8732 | ||
8733 | @smallexample | |
f7dc1244 | 8734 | (@value{GDBP}) set target-charset |
b383017d | 8735 | ASCII EBCDIC-US IBM1047 ISO-8859-1 |
f7dc1244 | 8736 | (@value{GDBP}) set target-charset |
10998722 | 8737 | @end smallexample |
a0eb71c5 KB |
8738 | |
8739 | We can select @sc{ibm1047} as our target character set, and examine the | |
8740 | program's strings again. Now the @sc{ascii} string is wrong, but | |
8741 | @value{GDBN} translates the contents of @code{ibm1047_hello} from the | |
8742 | target character set, @sc{ibm1047}, to the host character set, | |
8743 | @sc{ascii}, and they display correctly: | |
8744 | ||
8745 | @smallexample | |
f7dc1244 EZ |
8746 | (@value{GDBP}) set target-charset IBM1047 |
8747 | (@value{GDBP}) show charset | |
e33d66ec EZ |
8748 | The current host character set is `ASCII'. |
8749 | The current target character set is `IBM1047'. | |
f7dc1244 | 8750 | (@value{GDBP}) print ascii_hello |
a0eb71c5 | 8751 | $6 = 0x401698 "\110\145%%?\054\040\167?\162%\144\041\012" |
f7dc1244 | 8752 | (@value{GDBP}) print ascii_hello[0] |
a0eb71c5 | 8753 | $7 = 72 '\110' |
f7dc1244 | 8754 | (@value{GDBP}) print ibm1047_hello |
a0eb71c5 | 8755 | $8 = 0x4016a8 "Hello, world!\n" |
f7dc1244 | 8756 | (@value{GDBP}) print ibm1047_hello[0] |
a0eb71c5 | 8757 | $9 = 200 'H' |
f7dc1244 | 8758 | (@value{GDBP}) |
10998722 | 8759 | @end smallexample |
a0eb71c5 KB |
8760 | |
8761 | As above, @value{GDBN} uses the target character set for character and | |
8762 | string literals you use in expressions: | |
8763 | ||
8764 | @smallexample | |
f7dc1244 | 8765 | (@value{GDBP}) print '+' |
a0eb71c5 | 8766 | $10 = 78 '+' |
f7dc1244 | 8767 | (@value{GDBP}) |
10998722 | 8768 | @end smallexample |
a0eb71c5 | 8769 | |
e33d66ec | 8770 | The @sc{ibm1047} character set uses the number 78 to encode the @samp{+} |
a0eb71c5 KB |
8771 | character. |
8772 | ||
09d4efe1 EZ |
8773 | @node Caching Remote Data |
8774 | @section Caching Data of Remote Targets | |
8775 | @cindex caching data of remote targets | |
8776 | ||
4e5d721f | 8777 | @value{GDBN} caches data exchanged between the debugger and a |
ea35711c | 8778 | remote target (@pxref{Remote Debugging}). Such caching generally improves |
09d4efe1 | 8779 | performance, because it reduces the overhead of the remote protocol by |
4e5d721f DE |
8780 | bundling memory reads and writes into large chunks. Unfortunately, simply |
8781 | caching everything would lead to incorrect results, since @value{GDBN} | |
8782 | does not necessarily know anything about volatile values, memory-mapped I/O | |
29b090c0 DE |
8783 | addresses, etc. Furthermore, in non-stop mode (@pxref{Non-Stop Mode}) |
8784 | memory can be changed @emph{while} a gdb command is executing. | |
8785 | Therefore, by default, @value{GDBN} only caches data | |
8786 | known to be on the stack@footnote{In non-stop mode, it is moderately | |
8787 | rare for a running thread to modify the stack of a stopped thread | |
8788 | in a way that would interfere with a backtrace, and caching of | |
8789 | stack reads provides a significant speed up of remote backtraces.}. | |
8790 | Other regions of memory can be explicitly marked as | |
4e5d721f | 8791 | cacheable; see @pxref{Memory Region Attributes}. |
09d4efe1 EZ |
8792 | |
8793 | @table @code | |
8794 | @kindex set remotecache | |
8795 | @item set remotecache on | |
8796 | @itemx set remotecache off | |
4e5d721f DE |
8797 | This option no longer does anything; it exists for compatibility |
8798 | with old scripts. | |
09d4efe1 EZ |
8799 | |
8800 | @kindex show remotecache | |
8801 | @item show remotecache | |
4e5d721f DE |
8802 | Show the current state of the obsolete remotecache flag. |
8803 | ||
8804 | @kindex set stack-cache | |
8805 | @item set stack-cache on | |
8806 | @itemx set stack-cache off | |
8807 | Enable or disable caching of stack accesses. When @code{ON}, use | |
8808 | caching. By default, this option is @code{ON}. | |
8809 | ||
8810 | @kindex show stack-cache | |
8811 | @item show stack-cache | |
8812 | Show the current state of data caching for memory accesses. | |
09d4efe1 EZ |
8813 | |
8814 | @kindex info dcache | |
4e5d721f | 8815 | @item info dcache @r{[}line@r{]} |
09d4efe1 | 8816 | Print the information about the data cache performance. The |
4e5d721f DE |
8817 | information displayed includes the dcache width and depth, and for |
8818 | each cache line, its number, address, and how many times it was | |
8819 | referenced. This command is useful for debugging the data cache | |
8820 | operation. | |
8821 | ||
8822 | If a line number is specified, the contents of that line will be | |
8823 | printed in hex. | |
09d4efe1 EZ |
8824 | @end table |
8825 | ||
08388c79 DE |
8826 | @node Searching Memory |
8827 | @section Search Memory | |
8828 | @cindex searching memory | |
8829 | ||
8830 | Memory can be searched for a particular sequence of bytes with the | |
8831 | @code{find} command. | |
8832 | ||
8833 | @table @code | |
8834 | @kindex find | |
8835 | @item find @r{[}/@var{sn}@r{]} @var{start_addr}, +@var{len}, @var{val1} @r{[}, @var{val2}, @dots{}@r{]} | |
8836 | @itemx find @r{[}/@var{sn}@r{]} @var{start_addr}, @var{end_addr}, @var{val1} @r{[}, @var{val2}, @dots{}@r{]} | |
8837 | Search memory for the sequence of bytes specified by @var{val1}, @var{val2}, | |
8838 | etc. The search begins at address @var{start_addr} and continues for either | |
8839 | @var{len} bytes or through to @var{end_addr} inclusive. | |
8840 | @end table | |
8841 | ||
8842 | @var{s} and @var{n} are optional parameters. | |
8843 | They may be specified in either order, apart or together. | |
8844 | ||
8845 | @table @r | |
8846 | @item @var{s}, search query size | |
8847 | The size of each search query value. | |
8848 | ||
8849 | @table @code | |
8850 | @item b | |
8851 | bytes | |
8852 | @item h | |
8853 | halfwords (two bytes) | |
8854 | @item w | |
8855 | words (four bytes) | |
8856 | @item g | |
8857 | giant words (eight bytes) | |
8858 | @end table | |
8859 | ||
8860 | All values are interpreted in the current language. | |
8861 | This means, for example, that if the current source language is C/C@t{++} | |
8862 | then searching for the string ``hello'' includes the trailing '\0'. | |
8863 | ||
8864 | If the value size is not specified, it is taken from the | |
8865 | value's type in the current language. | |
8866 | This is useful when one wants to specify the search | |
8867 | pattern as a mixture of types. | |
8868 | Note that this means, for example, that in the case of C-like languages | |
8869 | a search for an untyped 0x42 will search for @samp{(int) 0x42} | |
8870 | which is typically four bytes. | |
8871 | ||
8872 | @item @var{n}, maximum number of finds | |
8873 | The maximum number of matches to print. The default is to print all finds. | |
8874 | @end table | |
8875 | ||
8876 | You can use strings as search values. Quote them with double-quotes | |
8877 | (@code{"}). | |
8878 | The string value is copied into the search pattern byte by byte, | |
8879 | regardless of the endianness of the target and the size specification. | |
8880 | ||
8881 | The address of each match found is printed as well as a count of the | |
8882 | number of matches found. | |
8883 | ||
8884 | The address of the last value found is stored in convenience variable | |
8885 | @samp{$_}. | |
8886 | A count of the number of matches is stored in @samp{$numfound}. | |
8887 | ||
8888 | For example, if stopped at the @code{printf} in this function: | |
8889 | ||
8890 | @smallexample | |
8891 | void | |
8892 | hello () | |
8893 | @{ | |
8894 | static char hello[] = "hello-hello"; | |
8895 | static struct @{ char c; short s; int i; @} | |
8896 | __attribute__ ((packed)) mixed | |
8897 | = @{ 'c', 0x1234, 0x87654321 @}; | |
8898 | printf ("%s\n", hello); | |
8899 | @} | |
8900 | @end smallexample | |
8901 | ||
8902 | @noindent | |
8903 | you get during debugging: | |
8904 | ||
8905 | @smallexample | |
8906 | (gdb) find &hello[0], +sizeof(hello), "hello" | |
8907 | 0x804956d <hello.1620+6> | |
8908 | 1 pattern found | |
8909 | (gdb) find &hello[0], +sizeof(hello), 'h', 'e', 'l', 'l', 'o' | |
8910 | 0x8049567 <hello.1620> | |
8911 | 0x804956d <hello.1620+6> | |
8912 | 2 patterns found | |
8913 | (gdb) find /b1 &hello[0], +sizeof(hello), 'h', 0x65, 'l' | |
8914 | 0x8049567 <hello.1620> | |
8915 | 1 pattern found | |
8916 | (gdb) find &mixed, +sizeof(mixed), (char) 'c', (short) 0x1234, (int) 0x87654321 | |
8917 | 0x8049560 <mixed.1625> | |
8918 | 1 pattern found | |
8919 | (gdb) print $numfound | |
8920 | $1 = 1 | |
8921 | (gdb) print $_ | |
8922 | $2 = (void *) 0x8049560 | |
8923 | @end smallexample | |
a0eb71c5 | 8924 | |
edb3359d DJ |
8925 | @node Optimized Code |
8926 | @chapter Debugging Optimized Code | |
8927 | @cindex optimized code, debugging | |
8928 | @cindex debugging optimized code | |
8929 | ||
8930 | Almost all compilers support optimization. With optimization | |
8931 | disabled, the compiler generates assembly code that corresponds | |
8932 | directly to your source code, in a simplistic way. As the compiler | |
8933 | applies more powerful optimizations, the generated assembly code | |
8934 | diverges from your original source code. With help from debugging | |
8935 | information generated by the compiler, @value{GDBN} can map from | |
8936 | the running program back to constructs from your original source. | |
8937 | ||
8938 | @value{GDBN} is more accurate with optimization disabled. If you | |
8939 | can recompile without optimization, it is easier to follow the | |
8940 | progress of your program during debugging. But, there are many cases | |
8941 | where you may need to debug an optimized version. | |
8942 | ||
8943 | When you debug a program compiled with @samp{-g -O}, remember that the | |
8944 | optimizer has rearranged your code; the debugger shows you what is | |
8945 | really there. Do not be too surprised when the execution path does not | |
8946 | exactly match your source file! An extreme example: if you define a | |
8947 | variable, but never use it, @value{GDBN} never sees that | |
8948 | variable---because the compiler optimizes it out of existence. | |
8949 | ||
8950 | Some things do not work as well with @samp{-g -O} as with just | |
8951 | @samp{-g}, particularly on machines with instruction scheduling. If in | |
8952 | doubt, recompile with @samp{-g} alone, and if this fixes the problem, | |
8953 | please report it to us as a bug (including a test case!). | |
8954 | @xref{Variables}, for more information about debugging optimized code. | |
8955 | ||
8956 | @menu | |
8957 | * Inline Functions:: How @value{GDBN} presents inlining | |
8958 | @end menu | |
8959 | ||
8960 | @node Inline Functions | |
8961 | @section Inline Functions | |
8962 | @cindex inline functions, debugging | |
8963 | ||
8964 | @dfn{Inlining} is an optimization that inserts a copy of the function | |
8965 | body directly at each call site, instead of jumping to a shared | |
8966 | routine. @value{GDBN} displays inlined functions just like | |
8967 | non-inlined functions. They appear in backtraces. You can view their | |
8968 | arguments and local variables, step into them with @code{step}, skip | |
8969 | them with @code{next}, and escape from them with @code{finish}. | |
8970 | You can check whether a function was inlined by using the | |
8971 | @code{info frame} command. | |
8972 | ||
8973 | For @value{GDBN} to support inlined functions, the compiler must | |
8974 | record information about inlining in the debug information --- | |
8975 | @value{NGCC} using the @sc{dwarf 2} format does this, and several | |
8976 | other compilers do also. @value{GDBN} only supports inlined functions | |
8977 | when using @sc{dwarf 2}. Versions of @value{NGCC} before 4.1 | |
8978 | do not emit two required attributes (@samp{DW_AT_call_file} and | |
8979 | @samp{DW_AT_call_line}); @value{GDBN} does not display inlined | |
8980 | function calls with earlier versions of @value{NGCC}. It instead | |
8981 | displays the arguments and local variables of inlined functions as | |
8982 | local variables in the caller. | |
8983 | ||
8984 | The body of an inlined function is directly included at its call site; | |
8985 | unlike a non-inlined function, there are no instructions devoted to | |
8986 | the call. @value{GDBN} still pretends that the call site and the | |
8987 | start of the inlined function are different instructions. Stepping to | |
8988 | the call site shows the call site, and then stepping again shows | |
8989 | the first line of the inlined function, even though no additional | |
8990 | instructions are executed. | |
8991 | ||
8992 | This makes source-level debugging much clearer; you can see both the | |
8993 | context of the call and then the effect of the call. Only stepping by | |
8994 | a single instruction using @code{stepi} or @code{nexti} does not do | |
8995 | this; single instruction steps always show the inlined body. | |
8996 | ||
8997 | There are some ways that @value{GDBN} does not pretend that inlined | |
8998 | function calls are the same as normal calls: | |
8999 | ||
9000 | @itemize @bullet | |
9001 | @item | |
9002 | You cannot set breakpoints on inlined functions. @value{GDBN} | |
9003 | either reports that there is no symbol with that name, or else sets the | |
9004 | breakpoint only on non-inlined copies of the function. This limitation | |
9005 | will be removed in a future version of @value{GDBN}; until then, | |
9006 | set a breakpoint by line number on the first line of the inlined | |
9007 | function instead. | |
9008 | ||
9009 | @item | |
9010 | Setting breakpoints at the call site of an inlined function may not | |
9011 | work, because the call site does not contain any code. @value{GDBN} | |
9012 | may incorrectly move the breakpoint to the next line of the enclosing | |
9013 | function, after the call. This limitation will be removed in a future | |
9014 | version of @value{GDBN}; until then, set a breakpoint on an earlier line | |
9015 | or inside the inlined function instead. | |
9016 | ||
9017 | @item | |
9018 | @value{GDBN} cannot locate the return value of inlined calls after | |
9019 | using the @code{finish} command. This is a limitation of compiler-generated | |
9020 | debugging information; after @code{finish}, you can step to the next line | |
9021 | and print a variable where your program stored the return value. | |
9022 | ||
9023 | @end itemize | |
9024 | ||
9025 | ||
e2e0bcd1 JB |
9026 | @node Macros |
9027 | @chapter C Preprocessor Macros | |
9028 | ||
49efadf5 | 9029 | Some languages, such as C and C@t{++}, provide a way to define and invoke |
e2e0bcd1 JB |
9030 | ``preprocessor macros'' which expand into strings of tokens. |
9031 | @value{GDBN} can evaluate expressions containing macro invocations, show | |
9032 | the result of macro expansion, and show a macro's definition, including | |
9033 | where it was defined. | |
9034 | ||
9035 | You may need to compile your program specially to provide @value{GDBN} | |
9036 | with information about preprocessor macros. Most compilers do not | |
9037 | include macros in their debugging information, even when you compile | |
9038 | with the @option{-g} flag. @xref{Compilation}. | |
9039 | ||
9040 | A program may define a macro at one point, remove that definition later, | |
9041 | and then provide a different definition after that. Thus, at different | |
9042 | points in the program, a macro may have different definitions, or have | |
9043 | no definition at all. If there is a current stack frame, @value{GDBN} | |
9044 | uses the macros in scope at that frame's source code line. Otherwise, | |
9045 | @value{GDBN} uses the macros in scope at the current listing location; | |
9046 | see @ref{List}. | |
9047 | ||
e2e0bcd1 JB |
9048 | Whenever @value{GDBN} evaluates an expression, it always expands any |
9049 | macro invocations present in the expression. @value{GDBN} also provides | |
9050 | the following commands for working with macros explicitly. | |
9051 | ||
9052 | @table @code | |
9053 | ||
9054 | @kindex macro expand | |
9055 | @cindex macro expansion, showing the results of preprocessor | |
9056 | @cindex preprocessor macro expansion, showing the results of | |
9057 | @cindex expanding preprocessor macros | |
9058 | @item macro expand @var{expression} | |
9059 | @itemx macro exp @var{expression} | |
9060 | Show the results of expanding all preprocessor macro invocations in | |
9061 | @var{expression}. Since @value{GDBN} simply expands macros, but does | |
9062 | not parse the result, @var{expression} need not be a valid expression; | |
9063 | it can be any string of tokens. | |
9064 | ||
09d4efe1 | 9065 | @kindex macro exp1 |
e2e0bcd1 JB |
9066 | @item macro expand-once @var{expression} |
9067 | @itemx macro exp1 @var{expression} | |
4644b6e3 | 9068 | @cindex expand macro once |
e2e0bcd1 JB |
9069 | @i{(This command is not yet implemented.)} Show the results of |
9070 | expanding those preprocessor macro invocations that appear explicitly in | |
9071 | @var{expression}. Macro invocations appearing in that expansion are | |
9072 | left unchanged. This command allows you to see the effect of a | |
9073 | particular macro more clearly, without being confused by further | |
9074 | expansions. Since @value{GDBN} simply expands macros, but does not | |
9075 | parse the result, @var{expression} need not be a valid expression; it | |
9076 | can be any string of tokens. | |
9077 | ||
475b0867 | 9078 | @kindex info macro |
e2e0bcd1 JB |
9079 | @cindex macro definition, showing |
9080 | @cindex definition, showing a macro's | |
475b0867 | 9081 | @item info macro @var{macro} |
e2e0bcd1 | 9082 | Show the definition of the macro named @var{macro}, and describe the |
484086b7 | 9083 | source location or compiler command-line where that definition was established. |
e2e0bcd1 JB |
9084 | |
9085 | @kindex macro define | |
9086 | @cindex user-defined macros | |
9087 | @cindex defining macros interactively | |
9088 | @cindex macros, user-defined | |
9089 | @item macro define @var{macro} @var{replacement-list} | |
9090 | @itemx macro define @var{macro}(@var{arglist}) @var{replacement-list} | |
d7d9f01e TT |
9091 | Introduce a definition for a preprocessor macro named @var{macro}, |
9092 | invocations of which are replaced by the tokens given in | |
9093 | @var{replacement-list}. The first form of this command defines an | |
9094 | ``object-like'' macro, which takes no arguments; the second form | |
9095 | defines a ``function-like'' macro, which takes the arguments given in | |
9096 | @var{arglist}. | |
9097 | ||
9098 | A definition introduced by this command is in scope in every | |
9099 | expression evaluated in @value{GDBN}, until it is removed with the | |
9100 | @code{macro undef} command, described below. The definition overrides | |
9101 | all definitions for @var{macro} present in the program being debugged, | |
9102 | as well as any previous user-supplied definition. | |
e2e0bcd1 JB |
9103 | |
9104 | @kindex macro undef | |
9105 | @item macro undef @var{macro} | |
d7d9f01e TT |
9106 | Remove any user-supplied definition for the macro named @var{macro}. |
9107 | This command only affects definitions provided with the @code{macro | |
9108 | define} command, described above; it cannot remove definitions present | |
9109 | in the program being debugged. | |
e2e0bcd1 | 9110 | |
09d4efe1 EZ |
9111 | @kindex macro list |
9112 | @item macro list | |
d7d9f01e | 9113 | List all the macros defined using the @code{macro define} command. |
e2e0bcd1 JB |
9114 | @end table |
9115 | ||
9116 | @cindex macros, example of debugging with | |
9117 | Here is a transcript showing the above commands in action. First, we | |
9118 | show our source files: | |
9119 | ||
9120 | @smallexample | |
9121 | $ cat sample.c | |
9122 | #include <stdio.h> | |
9123 | #include "sample.h" | |
9124 | ||
9125 | #define M 42 | |
9126 | #define ADD(x) (M + x) | |
9127 | ||
9128 | main () | |
9129 | @{ | |
9130 | #define N 28 | |
9131 | printf ("Hello, world!\n"); | |
9132 | #undef N | |
9133 | printf ("We're so creative.\n"); | |
9134 | #define N 1729 | |
9135 | printf ("Goodbye, world!\n"); | |
9136 | @} | |
9137 | $ cat sample.h | |
9138 | #define Q < | |
9139 | $ | |
9140 | @end smallexample | |
9141 | ||
9142 | Now, we compile the program using the @sc{gnu} C compiler, @value{NGCC}. | |
9143 | We pass the @option{-gdwarf-2} and @option{-g3} flags to ensure the | |
9144 | compiler includes information about preprocessor macros in the debugging | |
9145 | information. | |
9146 | ||
9147 | @smallexample | |
9148 | $ gcc -gdwarf-2 -g3 sample.c -o sample | |
9149 | $ | |
9150 | @end smallexample | |
9151 | ||
9152 | Now, we start @value{GDBN} on our sample program: | |
9153 | ||
9154 | @smallexample | |
9155 | $ gdb -nw sample | |
9156 | GNU gdb 2002-05-06-cvs | |
9157 | Copyright 2002 Free Software Foundation, Inc. | |
9158 | GDB is free software, @dots{} | |
f7dc1244 | 9159 | (@value{GDBP}) |
e2e0bcd1 JB |
9160 | @end smallexample |
9161 | ||
9162 | We can expand macros and examine their definitions, even when the | |
9163 | program is not running. @value{GDBN} uses the current listing position | |
9164 | to decide which macro definitions are in scope: | |
9165 | ||
9166 | @smallexample | |
f7dc1244 | 9167 | (@value{GDBP}) list main |
e2e0bcd1 JB |
9168 | 3 |
9169 | 4 #define M 42 | |
9170 | 5 #define ADD(x) (M + x) | |
9171 | 6 | |
9172 | 7 main () | |
9173 | 8 @{ | |
9174 | 9 #define N 28 | |
9175 | 10 printf ("Hello, world!\n"); | |
9176 | 11 #undef N | |
9177 | 12 printf ("We're so creative.\n"); | |
f7dc1244 | 9178 | (@value{GDBP}) info macro ADD |
e2e0bcd1 JB |
9179 | Defined at /home/jimb/gdb/macros/play/sample.c:5 |
9180 | #define ADD(x) (M + x) | |
f7dc1244 | 9181 | (@value{GDBP}) info macro Q |
e2e0bcd1 JB |
9182 | Defined at /home/jimb/gdb/macros/play/sample.h:1 |
9183 | included at /home/jimb/gdb/macros/play/sample.c:2 | |
9184 | #define Q < | |
f7dc1244 | 9185 | (@value{GDBP}) macro expand ADD(1) |
e2e0bcd1 | 9186 | expands to: (42 + 1) |
f7dc1244 | 9187 | (@value{GDBP}) macro expand-once ADD(1) |
e2e0bcd1 | 9188 | expands to: once (M + 1) |
f7dc1244 | 9189 | (@value{GDBP}) |
e2e0bcd1 JB |
9190 | @end smallexample |
9191 | ||
d7d9f01e | 9192 | In the example above, note that @code{macro expand-once} expands only |
e2e0bcd1 JB |
9193 | the macro invocation explicit in the original text --- the invocation of |
9194 | @code{ADD} --- but does not expand the invocation of the macro @code{M}, | |
9195 | which was introduced by @code{ADD}. | |
9196 | ||
3f94c067 BW |
9197 | Once the program is running, @value{GDBN} uses the macro definitions in |
9198 | force at the source line of the current stack frame: | |
e2e0bcd1 JB |
9199 | |
9200 | @smallexample | |
f7dc1244 | 9201 | (@value{GDBP}) break main |
e2e0bcd1 | 9202 | Breakpoint 1 at 0x8048370: file sample.c, line 10. |
f7dc1244 | 9203 | (@value{GDBP}) run |
b383017d | 9204 | Starting program: /home/jimb/gdb/macros/play/sample |
e2e0bcd1 JB |
9205 | |
9206 | Breakpoint 1, main () at sample.c:10 | |
9207 | 10 printf ("Hello, world!\n"); | |
f7dc1244 | 9208 | (@value{GDBP}) |
e2e0bcd1 JB |
9209 | @end smallexample |
9210 | ||
9211 | At line 10, the definition of the macro @code{N} at line 9 is in force: | |
9212 | ||
9213 | @smallexample | |
f7dc1244 | 9214 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
9215 | Defined at /home/jimb/gdb/macros/play/sample.c:9 |
9216 | #define N 28 | |
f7dc1244 | 9217 | (@value{GDBP}) macro expand N Q M |
e2e0bcd1 | 9218 | expands to: 28 < 42 |
f7dc1244 | 9219 | (@value{GDBP}) print N Q M |
e2e0bcd1 | 9220 | $1 = 1 |
f7dc1244 | 9221 | (@value{GDBP}) |
e2e0bcd1 JB |
9222 | @end smallexample |
9223 | ||
9224 | As we step over directives that remove @code{N}'s definition, and then | |
9225 | give it a new definition, @value{GDBN} finds the definition (or lack | |
9226 | thereof) in force at each point: | |
9227 | ||
9228 | @smallexample | |
f7dc1244 | 9229 | (@value{GDBP}) next |
e2e0bcd1 JB |
9230 | Hello, world! |
9231 | 12 printf ("We're so creative.\n"); | |
f7dc1244 | 9232 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
9233 | The symbol `N' has no definition as a C/C++ preprocessor macro |
9234 | at /home/jimb/gdb/macros/play/sample.c:12 | |
f7dc1244 | 9235 | (@value{GDBP}) next |
e2e0bcd1 JB |
9236 | We're so creative. |
9237 | 14 printf ("Goodbye, world!\n"); | |
f7dc1244 | 9238 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
9239 | Defined at /home/jimb/gdb/macros/play/sample.c:13 |
9240 | #define N 1729 | |
f7dc1244 | 9241 | (@value{GDBP}) macro expand N Q M |
e2e0bcd1 | 9242 | expands to: 1729 < 42 |
f7dc1244 | 9243 | (@value{GDBP}) print N Q M |
e2e0bcd1 | 9244 | $2 = 0 |
f7dc1244 | 9245 | (@value{GDBP}) |
e2e0bcd1 JB |
9246 | @end smallexample |
9247 | ||
484086b7 JK |
9248 | In addition to source files, macros can be defined on the compilation command |
9249 | line using the @option{-D@var{name}=@var{value}} syntax. For macros defined in | |
9250 | such a way, @value{GDBN} displays the location of their definition as line zero | |
9251 | of the source file submitted to the compiler. | |
9252 | ||
9253 | @smallexample | |
9254 | (@value{GDBP}) info macro __STDC__ | |
9255 | Defined at /home/jimb/gdb/macros/play/sample.c:0 | |
9256 | -D__STDC__=1 | |
9257 | (@value{GDBP}) | |
9258 | @end smallexample | |
9259 | ||
e2e0bcd1 | 9260 | |
b37052ae EZ |
9261 | @node Tracepoints |
9262 | @chapter Tracepoints | |
9263 | @c This chapter is based on the documentation written by Michael | |
9264 | @c Snyder, David Taylor, Jim Blandy, and Elena Zannoni. | |
9265 | ||
9266 | @cindex tracepoints | |
9267 | In some applications, it is not feasible for the debugger to interrupt | |
9268 | the program's execution long enough for the developer to learn | |
9269 | anything helpful about its behavior. If the program's correctness | |
9270 | depends on its real-time behavior, delays introduced by a debugger | |
9271 | might cause the program to change its behavior drastically, or perhaps | |
9272 | fail, even when the code itself is correct. It is useful to be able | |
9273 | to observe the program's behavior without interrupting it. | |
9274 | ||
9275 | Using @value{GDBN}'s @code{trace} and @code{collect} commands, you can | |
9276 | specify locations in the program, called @dfn{tracepoints}, and | |
9277 | arbitrary expressions to evaluate when those tracepoints are reached. | |
9278 | Later, using the @code{tfind} command, you can examine the values | |
9279 | those expressions had when the program hit the tracepoints. The | |
9280 | expressions may also denote objects in memory---structures or arrays, | |
9281 | for example---whose values @value{GDBN} should record; while visiting | |
9282 | a particular tracepoint, you may inspect those objects as if they were | |
9283 | in memory at that moment. However, because @value{GDBN} records these | |
9284 | values without interacting with you, it can do so quickly and | |
9285 | unobtrusively, hopefully not disturbing the program's behavior. | |
9286 | ||
9287 | The tracepoint facility is currently available only for remote | |
9d29849a JB |
9288 | targets. @xref{Targets}. In addition, your remote target must know |
9289 | how to collect trace data. This functionality is implemented in the | |
9290 | remote stub; however, none of the stubs distributed with @value{GDBN} | |
9291 | support tracepoints as of this writing. The format of the remote | |
9292 | packets used to implement tracepoints are described in @ref{Tracepoint | |
9293 | Packets}. | |
b37052ae EZ |
9294 | |
9295 | This chapter describes the tracepoint commands and features. | |
9296 | ||
9297 | @menu | |
b383017d RM |
9298 | * Set Tracepoints:: |
9299 | * Analyze Collected Data:: | |
9300 | * Tracepoint Variables:: | |
b37052ae EZ |
9301 | @end menu |
9302 | ||
9303 | @node Set Tracepoints | |
9304 | @section Commands to Set Tracepoints | |
9305 | ||
9306 | Before running such a @dfn{trace experiment}, an arbitrary number of | |
1042e4c0 SS |
9307 | tracepoints can be set. A tracepoint is actually a special type of |
9308 | breakpoint (@pxref{Set Breaks}), so you can manipulate it using | |
9309 | standard breakpoint commands. For instance, as with breakpoints, | |
9310 | tracepoint numbers are successive integers starting from one, and many | |
9311 | of the commands associated with tracepoints take the tracepoint number | |
9312 | as their argument, to identify which tracepoint to work on. | |
b37052ae EZ |
9313 | |
9314 | For each tracepoint, you can specify, in advance, some arbitrary set | |
9315 | of data that you want the target to collect in the trace buffer when | |
9316 | it hits that tracepoint. The collected data can include registers, | |
9317 | local variables, or global data. Later, you can use @value{GDBN} | |
9318 | commands to examine the values these data had at the time the | |
9319 | tracepoint was hit. | |
9320 | ||
1042e4c0 SS |
9321 | Tracepoints do not support every breakpoint feature. Conditional |
9322 | expressions and ignore counts on tracepoints have no effect, and | |
9323 | tracepoints cannot run @value{GDBN} commands when they are | |
9324 | hit. Tracepoints may not be thread-specific either. | |
9325 | ||
b37052ae EZ |
9326 | This section describes commands to set tracepoints and associated |
9327 | conditions and actions. | |
9328 | ||
9329 | @menu | |
b383017d RM |
9330 | * Create and Delete Tracepoints:: |
9331 | * Enable and Disable Tracepoints:: | |
9332 | * Tracepoint Passcounts:: | |
782b2b07 | 9333 | * Tracepoint Conditions:: |
f61e138d | 9334 | * Trace State Variables:: |
b383017d RM |
9335 | * Tracepoint Actions:: |
9336 | * Listing Tracepoints:: | |
79a6e687 | 9337 | * Starting and Stopping Trace Experiments:: |
b37052ae EZ |
9338 | @end menu |
9339 | ||
9340 | @node Create and Delete Tracepoints | |
9341 | @subsection Create and Delete Tracepoints | |
9342 | ||
9343 | @table @code | |
9344 | @cindex set tracepoint | |
9345 | @kindex trace | |
1042e4c0 | 9346 | @item trace @var{location} |
b37052ae | 9347 | The @code{trace} command is very similar to the @code{break} command. |
1042e4c0 SS |
9348 | Its argument @var{location} can be a source line, a function name, or |
9349 | an address in the target program. @xref{Specify Location}. The | |
9350 | @code{trace} command defines a tracepoint, which is a point in the | |
9351 | target program where the debugger will briefly stop, collect some | |
9352 | data, and then allow the program to continue. Setting a tracepoint or | |
9353 | changing its actions doesn't take effect until the next @code{tstart} | |
9354 | command, and once a trace experiment is running, further changes will | |
9355 | not have any effect until the next trace experiment starts. | |
b37052ae EZ |
9356 | |
9357 | Here are some examples of using the @code{trace} command: | |
9358 | ||
9359 | @smallexample | |
9360 | (@value{GDBP}) @b{trace foo.c:121} // a source file and line number | |
9361 | ||
9362 | (@value{GDBP}) @b{trace +2} // 2 lines forward | |
9363 | ||
9364 | (@value{GDBP}) @b{trace my_function} // first source line of function | |
9365 | ||
9366 | (@value{GDBP}) @b{trace *my_function} // EXACT start address of function | |
9367 | ||
9368 | (@value{GDBP}) @b{trace *0x2117c4} // an address | |
9369 | @end smallexample | |
9370 | ||
9371 | @noindent | |
9372 | You can abbreviate @code{trace} as @code{tr}. | |
9373 | ||
782b2b07 SS |
9374 | @item trace @var{location} if @var{cond} |
9375 | Set a tracepoint with condition @var{cond}; evaluate the expression | |
9376 | @var{cond} each time the tracepoint is reached, and collect data only | |
9377 | if the value is nonzero---that is, if @var{cond} evaluates as true. | |
9378 | @xref{Tracepoint Conditions, ,Tracepoint Conditions}, for more | |
9379 | information on tracepoint conditions. | |
9380 | ||
b37052ae EZ |
9381 | @vindex $tpnum |
9382 | @cindex last tracepoint number | |
9383 | @cindex recent tracepoint number | |
9384 | @cindex tracepoint number | |
9385 | The convenience variable @code{$tpnum} records the tracepoint number | |
9386 | of the most recently set tracepoint. | |
9387 | ||
9388 | @kindex delete tracepoint | |
9389 | @cindex tracepoint deletion | |
9390 | @item delete tracepoint @r{[}@var{num}@r{]} | |
9391 | Permanently delete one or more tracepoints. With no argument, the | |
1042e4c0 SS |
9392 | default is to delete all tracepoints. Note that the regular |
9393 | @code{delete} command can remove tracepoints also. | |
b37052ae EZ |
9394 | |
9395 | Examples: | |
9396 | ||
9397 | @smallexample | |
9398 | (@value{GDBP}) @b{delete trace 1 2 3} // remove three tracepoints | |
9399 | ||
9400 | (@value{GDBP}) @b{delete trace} // remove all tracepoints | |
9401 | @end smallexample | |
9402 | ||
9403 | @noindent | |
9404 | You can abbreviate this command as @code{del tr}. | |
9405 | @end table | |
9406 | ||
9407 | @node Enable and Disable Tracepoints | |
9408 | @subsection Enable and Disable Tracepoints | |
9409 | ||
1042e4c0 SS |
9410 | These commands are deprecated; they are equivalent to plain @code{disable} and @code{enable}. |
9411 | ||
b37052ae EZ |
9412 | @table @code |
9413 | @kindex disable tracepoint | |
9414 | @item disable tracepoint @r{[}@var{num}@r{]} | |
9415 | Disable tracepoint @var{num}, or all tracepoints if no argument | |
9416 | @var{num} is given. A disabled tracepoint will have no effect during | |
9417 | the next trace experiment, but it is not forgotten. You can re-enable | |
9418 | a disabled tracepoint using the @code{enable tracepoint} command. | |
9419 | ||
9420 | @kindex enable tracepoint | |
9421 | @item enable tracepoint @r{[}@var{num}@r{]} | |
9422 | Enable tracepoint @var{num}, or all tracepoints. The enabled | |
9423 | tracepoints will become effective the next time a trace experiment is | |
9424 | run. | |
9425 | @end table | |
9426 | ||
9427 | @node Tracepoint Passcounts | |
9428 | @subsection Tracepoint Passcounts | |
9429 | ||
9430 | @table @code | |
9431 | @kindex passcount | |
9432 | @cindex tracepoint pass count | |
9433 | @item passcount @r{[}@var{n} @r{[}@var{num}@r{]]} | |
9434 | Set the @dfn{passcount} of a tracepoint. The passcount is a way to | |
9435 | automatically stop a trace experiment. If a tracepoint's passcount is | |
9436 | @var{n}, then the trace experiment will be automatically stopped on | |
9437 | the @var{n}'th time that tracepoint is hit. If the tracepoint number | |
9438 | @var{num} is not specified, the @code{passcount} command sets the | |
9439 | passcount of the most recently defined tracepoint. If no passcount is | |
9440 | given, the trace experiment will run until stopped explicitly by the | |
9441 | user. | |
9442 | ||
9443 | Examples: | |
9444 | ||
9445 | @smallexample | |
b383017d | 9446 | (@value{GDBP}) @b{passcount 5 2} // Stop on the 5th execution of |
6826cf00 | 9447 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// tracepoint 2} |
b37052ae EZ |
9448 | |
9449 | (@value{GDBP}) @b{passcount 12} // Stop on the 12th execution of the | |
6826cf00 | 9450 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// most recently defined tracepoint.} |
b37052ae EZ |
9451 | (@value{GDBP}) @b{trace foo} |
9452 | (@value{GDBP}) @b{pass 3} | |
9453 | (@value{GDBP}) @b{trace bar} | |
9454 | (@value{GDBP}) @b{pass 2} | |
9455 | (@value{GDBP}) @b{trace baz} | |
9456 | (@value{GDBP}) @b{pass 1} // Stop tracing when foo has been | |
6826cf00 EZ |
9457 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// executed 3 times OR when bar has} |
9458 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// been executed 2 times} | |
9459 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// OR when baz has been executed 1 time.} | |
b37052ae EZ |
9460 | @end smallexample |
9461 | @end table | |
9462 | ||
782b2b07 SS |
9463 | @node Tracepoint Conditions |
9464 | @subsection Tracepoint Conditions | |
9465 | @cindex conditional tracepoints | |
9466 | @cindex tracepoint conditions | |
9467 | ||
9468 | The simplest sort of tracepoint collects data every time your program | |
9469 | reaches a specified place. You can also specify a @dfn{condition} for | |
9470 | a tracepoint. A condition is just a Boolean expression in your | |
9471 | programming language (@pxref{Expressions, ,Expressions}). A | |
9472 | tracepoint with a condition evaluates the expression each time your | |
9473 | program reaches it, and data collection happens only if the condition | |
9474 | is true. | |
9475 | ||
9476 | Tracepoint conditions can be specified when a tracepoint is set, by | |
9477 | using @samp{if} in the arguments to the @code{trace} command. | |
9478 | @xref{Create and Delete Tracepoints, ,Setting Tracepoints}. They can | |
9479 | also be set or changed at any time with the @code{condition} command, | |
9480 | just as with breakpoints. | |
9481 | ||
9482 | Unlike breakpoint conditions, @value{GDBN} does not actually evaluate | |
9483 | the conditional expression itself. Instead, @value{GDBN} encodes the | |
9484 | expression into an agent expression (@pxref{Agent Expressions} | |
9485 | suitable for execution on the target, independently of @value{GDBN}. | |
9486 | Global variables become raw memory locations, locals become stack | |
9487 | accesses, and so forth. | |
9488 | ||
9489 | For instance, suppose you have a function that is usually called | |
9490 | frequently, but should not be called after an error has occurred. You | |
9491 | could use the following tracepoint command to collect data about calls | |
9492 | of that function that happen while the error code is propagating | |
9493 | through the program; an unconditional tracepoint could end up | |
9494 | collecting thousands of useless trace frames that you would have to | |
9495 | search through. | |
9496 | ||
9497 | @smallexample | |
9498 | (@value{GDBP}) @kbd{trace normal_operation if errcode > 0} | |
9499 | @end smallexample | |
9500 | ||
f61e138d SS |
9501 | @node Trace State Variables |
9502 | @subsection Trace State Variables | |
9503 | @cindex trace state variables | |
9504 | ||
9505 | A @dfn{trace state variable} is a special type of variable that is | |
9506 | created and managed by target-side code. The syntax is the same as | |
9507 | that for GDB's convenience variables (a string prefixed with ``$''), | |
9508 | but they are stored on the target. They must be created explicitly, | |
9509 | using a @code{tvariable} command. They are always 64-bit signed | |
9510 | integers. | |
9511 | ||
9512 | Trace state variables are remembered by @value{GDBN}, and downloaded | |
9513 | to the target along with tracepoint information when the trace | |
9514 | experiment starts. There are no intrinsic limits on the number of | |
9515 | trace state variables, beyond memory limitations of the target. | |
9516 | ||
9517 | @cindex convenience variables, and trace state variables | |
9518 | Although trace state variables are managed by the target, you can use | |
9519 | them in print commands and expressions as if they were convenience | |
9520 | variables; @value{GDBN} will get the current value from the target | |
9521 | while the trace experiment is running. Trace state variables share | |
9522 | the same namespace as other ``$'' variables, which means that you | |
9523 | cannot have trace state variables with names like @code{$23} or | |
9524 | @code{$pc}, nor can you have a trace state variable and a convenience | |
9525 | variable with the same name. | |
9526 | ||
9527 | @table @code | |
9528 | ||
9529 | @item tvariable $@var{name} [ = @var{expression} ] | |
9530 | @kindex tvariable | |
9531 | The @code{tvariable} command creates a new trace state variable named | |
9532 | @code{$@var{name}}, and optionally gives it an initial value of | |
9533 | @var{expression}. @var{expression} is evaluated when this command is | |
9534 | entered; the result will be converted to an integer if possible, | |
9535 | otherwise @value{GDBN} will report an error. A subsequent | |
9536 | @code{tvariable} command specifying the same name does not create a | |
9537 | variable, but instead assigns the supplied initial value to the | |
9538 | existing variable of that name, overwriting any previous initial | |
9539 | value. The default initial value is 0. | |
9540 | ||
9541 | @item info tvariables | |
9542 | @kindex info tvariables | |
9543 | List all the trace state variables along with their initial values. | |
9544 | Their current values may also be displayed, if the trace experiment is | |
9545 | currently running. | |
9546 | ||
9547 | @item delete tvariable @r{[} $@var{name} @dots{} @r{]} | |
9548 | @kindex delete tvariable | |
9549 | Delete the given trace state variables, or all of them if no arguments | |
9550 | are specified. | |
9551 | ||
9552 | @end table | |
9553 | ||
b37052ae EZ |
9554 | @node Tracepoint Actions |
9555 | @subsection Tracepoint Action Lists | |
9556 | ||
9557 | @table @code | |
9558 | @kindex actions | |
9559 | @cindex tracepoint actions | |
9560 | @item actions @r{[}@var{num}@r{]} | |
9561 | This command will prompt for a list of actions to be taken when the | |
9562 | tracepoint is hit. If the tracepoint number @var{num} is not | |
9563 | specified, this command sets the actions for the one that was most | |
9564 | recently defined (so that you can define a tracepoint and then say | |
9565 | @code{actions} without bothering about its number). You specify the | |
9566 | actions themselves on the following lines, one action at a time, and | |
9567 | terminate the actions list with a line containing just @code{end}. So | |
9568 | far, the only defined actions are @code{collect} and | |
9569 | @code{while-stepping}. | |
9570 | ||
9571 | @cindex remove actions from a tracepoint | |
9572 | To remove all actions from a tracepoint, type @samp{actions @var{num}} | |
9573 | and follow it immediately with @samp{end}. | |
9574 | ||
9575 | @smallexample | |
9576 | (@value{GDBP}) @b{collect @var{data}} // collect some data | |
9577 | ||
6826cf00 | 9578 | (@value{GDBP}) @b{while-stepping 5} // single-step 5 times, collect data |
b37052ae | 9579 | |
6826cf00 | 9580 | (@value{GDBP}) @b{end} // signals the end of actions. |
b37052ae EZ |
9581 | @end smallexample |
9582 | ||
9583 | In the following example, the action list begins with @code{collect} | |
9584 | commands indicating the things to be collected when the tracepoint is | |
9585 | hit. Then, in order to single-step and collect additional data | |
9586 | following the tracepoint, a @code{while-stepping} command is used, | |
9587 | followed by the list of things to be collected while stepping. The | |
9588 | @code{while-stepping} command is terminated by its own separate | |
9589 | @code{end} command. Lastly, the action list is terminated by an | |
9590 | @code{end} command. | |
9591 | ||
9592 | @smallexample | |
9593 | (@value{GDBP}) @b{trace foo} | |
9594 | (@value{GDBP}) @b{actions} | |
9595 | Enter actions for tracepoint 1, one per line: | |
9596 | > collect bar,baz | |
9597 | > collect $regs | |
9598 | > while-stepping 12 | |
9599 | > collect $fp, $sp | |
9600 | > end | |
9601 | end | |
9602 | @end smallexample | |
9603 | ||
9604 | @kindex collect @r{(tracepoints)} | |
9605 | @item collect @var{expr1}, @var{expr2}, @dots{} | |
9606 | Collect values of the given expressions when the tracepoint is hit. | |
9607 | This command accepts a comma-separated list of any valid expressions. | |
9608 | In addition to global, static, or local variables, the following | |
9609 | special arguments are supported: | |
9610 | ||
9611 | @table @code | |
9612 | @item $regs | |
9613 | collect all registers | |
9614 | ||
9615 | @item $args | |
9616 | collect all function arguments | |
9617 | ||
9618 | @item $locals | |
9619 | collect all local variables. | |
9620 | @end table | |
9621 | ||
9622 | You can give several consecutive @code{collect} commands, each one | |
9623 | with a single argument, or one @code{collect} command with several | |
9624 | arguments separated by commas: the effect is the same. | |
9625 | ||
f5c37c66 EZ |
9626 | The command @code{info scope} (@pxref{Symbols, info scope}) is |
9627 | particularly useful for figuring out what data to collect. | |
9628 | ||
6da95a67 SS |
9629 | @kindex teval @r{(tracepoints)} |
9630 | @item teval @var{expr1}, @var{expr2}, @dots{} | |
9631 | Evaluate the given expressions when the tracepoint is hit. This | |
9632 | command accepts a comma-separated list of expressions. The results | |
9633 | are discarded, so this is mainly useful for assigning values to trace | |
9634 | state variables (@pxref{Trace State Variables}) without adding those | |
9635 | values to the trace buffer, as would be the case if the @code{collect} | |
9636 | action were used. | |
9637 | ||
b37052ae EZ |
9638 | @kindex while-stepping @r{(tracepoints)} |
9639 | @item while-stepping @var{n} | |
9640 | Perform @var{n} single-step traces after the tracepoint, collecting | |
9641 | new data at each step. The @code{while-stepping} command is | |
9642 | followed by the list of what to collect while stepping (followed by | |
9643 | its own @code{end} command): | |
9644 | ||
9645 | @smallexample | |
9646 | > while-stepping 12 | |
9647 | > collect $regs, myglobal | |
9648 | > end | |
9649 | > | |
9650 | @end smallexample | |
9651 | ||
9652 | @noindent | |
9653 | You may abbreviate @code{while-stepping} as @code{ws} or | |
9654 | @code{stepping}. | |
236f1d4d SS |
9655 | |
9656 | @item set default-collect @var{expr1}, @var{expr2}, @dots{} | |
9657 | @kindex set default-collect | |
9658 | @cindex default collection action | |
9659 | This variable is a list of expressions to collect at each tracepoint | |
9660 | hit. It is effectively an additional @code{collect} action prepended | |
9661 | to every tracepoint action list. The expressions are parsed | |
9662 | individually for each tracepoint, so for instance a variable named | |
9663 | @code{xyz} may be interpreted as a global for one tracepoint, and a | |
9664 | local for another, as appropriate to the tracepoint's location. | |
9665 | ||
9666 | @item show default-collect | |
9667 | @kindex show default-collect | |
9668 | Show the list of expressions that are collected by default at each | |
9669 | tracepoint hit. | |
9670 | ||
b37052ae EZ |
9671 | @end table |
9672 | ||
9673 | @node Listing Tracepoints | |
9674 | @subsection Listing Tracepoints | |
9675 | ||
9676 | @table @code | |
9677 | @kindex info tracepoints | |
09d4efe1 | 9678 | @kindex info tp |
b37052ae EZ |
9679 | @cindex information about tracepoints |
9680 | @item info tracepoints @r{[}@var{num}@r{]} | |
1042e4c0 SS |
9681 | Display information about the tracepoint @var{num}. If you don't |
9682 | specify a tracepoint number, displays information about all the | |
9683 | tracepoints defined so far. The format is similar to that used for | |
9684 | @code{info breakpoints}; in fact, @code{info tracepoints} is the same | |
9685 | command, simply restricting itself to tracepoints. | |
9686 | ||
9687 | A tracepoint's listing may include additional information specific to | |
9688 | tracing: | |
b37052ae EZ |
9689 | |
9690 | @itemize @bullet | |
9691 | @item | |
b37052ae EZ |
9692 | its passcount as given by the @code{passcount @var{n}} command |
9693 | @item | |
9694 | its step count as given by the @code{while-stepping @var{n}} command | |
9695 | @item | |
1042e4c0 SS |
9696 | its action list as given by the @code{actions} command. The actions |
9697 | are prefixed with an @samp{A} so as to distinguish them from commands. | |
b37052ae EZ |
9698 | @end itemize |
9699 | ||
9700 | @smallexample | |
9701 | (@value{GDBP}) @b{info trace} | |
1042e4c0 SS |
9702 | Num Type Disp Enb Address What |
9703 | 1 tracepoint keep y 0x0804ab57 in foo() at main.cxx:7 | |
9704 | pass count 1200 | |
9705 | step count 20 | |
9706 | A while-stepping 20 | |
9707 | A collect globfoo, $regs | |
9708 | A end | |
9709 | A collect globfoo2 | |
9710 | A end | |
b37052ae EZ |
9711 | (@value{GDBP}) |
9712 | @end smallexample | |
9713 | ||
9714 | @noindent | |
9715 | This command can be abbreviated @code{info tp}. | |
9716 | @end table | |
9717 | ||
79a6e687 BW |
9718 | @node Starting and Stopping Trace Experiments |
9719 | @subsection Starting and Stopping Trace Experiments | |
b37052ae EZ |
9720 | |
9721 | @table @code | |
9722 | @kindex tstart | |
9723 | @cindex start a new trace experiment | |
9724 | @cindex collected data discarded | |
9725 | @item tstart | |
9726 | This command takes no arguments. It starts the trace experiment, and | |
9727 | begins collecting data. This has the side effect of discarding all | |
9728 | the data collected in the trace buffer during the previous trace | |
9729 | experiment. | |
9730 | ||
9731 | @kindex tstop | |
9732 | @cindex stop a running trace experiment | |
9733 | @item tstop | |
9734 | This command takes no arguments. It ends the trace experiment, and | |
9735 | stops collecting data. | |
9736 | ||
68c71a2e | 9737 | @strong{Note}: a trace experiment and data collection may stop |
b37052ae EZ |
9738 | automatically if any tracepoint's passcount is reached |
9739 | (@pxref{Tracepoint Passcounts}), or if the trace buffer becomes full. | |
9740 | ||
9741 | @kindex tstatus | |
9742 | @cindex status of trace data collection | |
9743 | @cindex trace experiment, status of | |
9744 | @item tstatus | |
9745 | This command displays the status of the current trace data | |
9746 | collection. | |
9747 | @end table | |
9748 | ||
9749 | Here is an example of the commands we described so far: | |
9750 | ||
9751 | @smallexample | |
9752 | (@value{GDBP}) @b{trace gdb_c_test} | |
9753 | (@value{GDBP}) @b{actions} | |
9754 | Enter actions for tracepoint #1, one per line. | |
9755 | > collect $regs,$locals,$args | |
9756 | > while-stepping 11 | |
9757 | > collect $regs | |
9758 | > end | |
9759 | > end | |
9760 | (@value{GDBP}) @b{tstart} | |
9761 | [time passes @dots{}] | |
9762 | (@value{GDBP}) @b{tstop} | |
9763 | @end smallexample | |
9764 | ||
9765 | ||
9766 | @node Analyze Collected Data | |
79a6e687 | 9767 | @section Using the Collected Data |
b37052ae EZ |
9768 | |
9769 | After the tracepoint experiment ends, you use @value{GDBN} commands | |
9770 | for examining the trace data. The basic idea is that each tracepoint | |
9771 | collects a trace @dfn{snapshot} every time it is hit and another | |
9772 | snapshot every time it single-steps. All these snapshots are | |
9773 | consecutively numbered from zero and go into a buffer, and you can | |
9774 | examine them later. The way you examine them is to @dfn{focus} on a | |
9775 | specific trace snapshot. When the remote stub is focused on a trace | |
9776 | snapshot, it will respond to all @value{GDBN} requests for memory and | |
9777 | registers by reading from the buffer which belongs to that snapshot, | |
9778 | rather than from @emph{real} memory or registers of the program being | |
9779 | debugged. This means that @strong{all} @value{GDBN} commands | |
9780 | (@code{print}, @code{info registers}, @code{backtrace}, etc.) will | |
9781 | behave as if we were currently debugging the program state as it was | |
9782 | when the tracepoint occurred. Any requests for data that are not in | |
9783 | the buffer will fail. | |
9784 | ||
9785 | @menu | |
9786 | * tfind:: How to select a trace snapshot | |
9787 | * tdump:: How to display all data for a snapshot | |
9788 | * save-tracepoints:: How to save tracepoints for a future run | |
9789 | @end menu | |
9790 | ||
9791 | @node tfind | |
9792 | @subsection @code{tfind @var{n}} | |
9793 | ||
9794 | @kindex tfind | |
9795 | @cindex select trace snapshot | |
9796 | @cindex find trace snapshot | |
9797 | The basic command for selecting a trace snapshot from the buffer is | |
9798 | @code{tfind @var{n}}, which finds trace snapshot number @var{n}, | |
9799 | counting from zero. If no argument @var{n} is given, the next | |
9800 | snapshot is selected. | |
9801 | ||
9802 | Here are the various forms of using the @code{tfind} command. | |
9803 | ||
9804 | @table @code | |
9805 | @item tfind start | |
9806 | Find the first snapshot in the buffer. This is a synonym for | |
9807 | @code{tfind 0} (since 0 is the number of the first snapshot). | |
9808 | ||
9809 | @item tfind none | |
9810 | Stop debugging trace snapshots, resume @emph{live} debugging. | |
9811 | ||
9812 | @item tfind end | |
9813 | Same as @samp{tfind none}. | |
9814 | ||
9815 | @item tfind | |
9816 | No argument means find the next trace snapshot. | |
9817 | ||
9818 | @item tfind - | |
9819 | Find the previous trace snapshot before the current one. This permits | |
9820 | retracing earlier steps. | |
9821 | ||
9822 | @item tfind tracepoint @var{num} | |
9823 | Find the next snapshot associated with tracepoint @var{num}. Search | |
9824 | proceeds forward from the last examined trace snapshot. If no | |
9825 | argument @var{num} is given, it means find the next snapshot collected | |
9826 | for the same tracepoint as the current snapshot. | |
9827 | ||
9828 | @item tfind pc @var{addr} | |
9829 | Find the next snapshot associated with the value @var{addr} of the | |
9830 | program counter. Search proceeds forward from the last examined trace | |
9831 | snapshot. If no argument @var{addr} is given, it means find the next | |
9832 | snapshot with the same value of PC as the current snapshot. | |
9833 | ||
9834 | @item tfind outside @var{addr1}, @var{addr2} | |
9835 | Find the next snapshot whose PC is outside the given range of | |
9836 | addresses. | |
9837 | ||
9838 | @item tfind range @var{addr1}, @var{addr2} | |
9839 | Find the next snapshot whose PC is between @var{addr1} and | |
9840 | @var{addr2}. @c FIXME: Is the range inclusive or exclusive? | |
9841 | ||
9842 | @item tfind line @r{[}@var{file}:@r{]}@var{n} | |
9843 | Find the next snapshot associated with the source line @var{n}. If | |
9844 | the optional argument @var{file} is given, refer to line @var{n} in | |
9845 | that source file. Search proceeds forward from the last examined | |
9846 | trace snapshot. If no argument @var{n} is given, it means find the | |
9847 | next line other than the one currently being examined; thus saying | |
9848 | @code{tfind line} repeatedly can appear to have the same effect as | |
9849 | stepping from line to line in a @emph{live} debugging session. | |
9850 | @end table | |
9851 | ||
9852 | The default arguments for the @code{tfind} commands are specifically | |
9853 | designed to make it easy to scan through the trace buffer. For | |
9854 | instance, @code{tfind} with no argument selects the next trace | |
9855 | snapshot, and @code{tfind -} with no argument selects the previous | |
9856 | trace snapshot. So, by giving one @code{tfind} command, and then | |
9857 | simply hitting @key{RET} repeatedly you can examine all the trace | |
9858 | snapshots in order. Or, by saying @code{tfind -} and then hitting | |
9859 | @key{RET} repeatedly you can examine the snapshots in reverse order. | |
9860 | The @code{tfind line} command with no argument selects the snapshot | |
9861 | for the next source line executed. The @code{tfind pc} command with | |
9862 | no argument selects the next snapshot with the same program counter | |
9863 | (PC) as the current frame. The @code{tfind tracepoint} command with | |
9864 | no argument selects the next trace snapshot collected by the same | |
9865 | tracepoint as the current one. | |
9866 | ||
9867 | In addition to letting you scan through the trace buffer manually, | |
9868 | these commands make it easy to construct @value{GDBN} scripts that | |
9869 | scan through the trace buffer and print out whatever collected data | |
9870 | you are interested in. Thus, if we want to examine the PC, FP, and SP | |
9871 | registers from each trace frame in the buffer, we can say this: | |
9872 | ||
9873 | @smallexample | |
9874 | (@value{GDBP}) @b{tfind start} | |
9875 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
9876 | > printf "Frame %d, PC = %08X, SP = %08X, FP = %08X\n", \ | |
9877 | $trace_frame, $pc, $sp, $fp | |
9878 | > tfind | |
9879 | > end | |
9880 | ||
9881 | Frame 0, PC = 0020DC64, SP = 0030BF3C, FP = 0030BF44 | |
9882 | Frame 1, PC = 0020DC6C, SP = 0030BF38, FP = 0030BF44 | |
9883 | Frame 2, PC = 0020DC70, SP = 0030BF34, FP = 0030BF44 | |
9884 | Frame 3, PC = 0020DC74, SP = 0030BF30, FP = 0030BF44 | |
9885 | Frame 4, PC = 0020DC78, SP = 0030BF2C, FP = 0030BF44 | |
9886 | Frame 5, PC = 0020DC7C, SP = 0030BF28, FP = 0030BF44 | |
9887 | Frame 6, PC = 0020DC80, SP = 0030BF24, FP = 0030BF44 | |
9888 | Frame 7, PC = 0020DC84, SP = 0030BF20, FP = 0030BF44 | |
9889 | Frame 8, PC = 0020DC88, SP = 0030BF1C, FP = 0030BF44 | |
9890 | Frame 9, PC = 0020DC8E, SP = 0030BF18, FP = 0030BF44 | |
9891 | Frame 10, PC = 00203F6C, SP = 0030BE3C, FP = 0030BF14 | |
9892 | @end smallexample | |
9893 | ||
9894 | Or, if we want to examine the variable @code{X} at each source line in | |
9895 | the buffer: | |
9896 | ||
9897 | @smallexample | |
9898 | (@value{GDBP}) @b{tfind start} | |
9899 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
9900 | > printf "Frame %d, X == %d\n", $trace_frame, X | |
9901 | > tfind line | |
9902 | > end | |
9903 | ||
9904 | Frame 0, X = 1 | |
9905 | Frame 7, X = 2 | |
9906 | Frame 13, X = 255 | |
9907 | @end smallexample | |
9908 | ||
9909 | @node tdump | |
9910 | @subsection @code{tdump} | |
9911 | @kindex tdump | |
9912 | @cindex dump all data collected at tracepoint | |
9913 | @cindex tracepoint data, display | |
9914 | ||
9915 | This command takes no arguments. It prints all the data collected at | |
9916 | the current trace snapshot. | |
9917 | ||
9918 | @smallexample | |
9919 | (@value{GDBP}) @b{trace 444} | |
9920 | (@value{GDBP}) @b{actions} | |
9921 | Enter actions for tracepoint #2, one per line: | |
9922 | > collect $regs, $locals, $args, gdb_long_test | |
9923 | > end | |
9924 | ||
9925 | (@value{GDBP}) @b{tstart} | |
9926 | ||
9927 | (@value{GDBP}) @b{tfind line 444} | |
9928 | #0 gdb_test (p1=0x11, p2=0x22, p3=0x33, p4=0x44, p5=0x55, p6=0x66) | |
9929 | at gdb_test.c:444 | |
9930 | 444 printp( "%s: arguments = 0x%X 0x%X 0x%X 0x%X 0x%X 0x%X\n", ) | |
9931 | ||
9932 | (@value{GDBP}) @b{tdump} | |
9933 | Data collected at tracepoint 2, trace frame 1: | |
9934 | d0 0xc4aa0085 -995491707 | |
9935 | d1 0x18 24 | |
9936 | d2 0x80 128 | |
9937 | d3 0x33 51 | |
9938 | d4 0x71aea3d 119204413 | |
9939 | d5 0x22 34 | |
9940 | d6 0xe0 224 | |
9941 | d7 0x380035 3670069 | |
9942 | a0 0x19e24a 1696330 | |
9943 | a1 0x3000668 50333288 | |
9944 | a2 0x100 256 | |
9945 | a3 0x322000 3284992 | |
9946 | a4 0x3000698 50333336 | |
9947 | a5 0x1ad3cc 1758156 | |
9948 | fp 0x30bf3c 0x30bf3c | |
9949 | sp 0x30bf34 0x30bf34 | |
9950 | ps 0x0 0 | |
9951 | pc 0x20b2c8 0x20b2c8 | |
9952 | fpcontrol 0x0 0 | |
9953 | fpstatus 0x0 0 | |
9954 | fpiaddr 0x0 0 | |
9955 | p = 0x20e5b4 "gdb-test" | |
9956 | p1 = (void *) 0x11 | |
9957 | p2 = (void *) 0x22 | |
9958 | p3 = (void *) 0x33 | |
9959 | p4 = (void *) 0x44 | |
9960 | p5 = (void *) 0x55 | |
9961 | p6 = (void *) 0x66 | |
9962 | gdb_long_test = 17 '\021' | |
9963 | ||
9964 | (@value{GDBP}) | |
9965 | @end smallexample | |
9966 | ||
9967 | @node save-tracepoints | |
9968 | @subsection @code{save-tracepoints @var{filename}} | |
9969 | @kindex save-tracepoints | |
9970 | @cindex save tracepoints for future sessions | |
9971 | ||
9972 | This command saves all current tracepoint definitions together with | |
9973 | their actions and passcounts, into a file @file{@var{filename}} | |
9974 | suitable for use in a later debugging session. To read the saved | |
9975 | tracepoint definitions, use the @code{source} command (@pxref{Command | |
9976 | Files}). | |
9977 | ||
9978 | @node Tracepoint Variables | |
9979 | @section Convenience Variables for Tracepoints | |
9980 | @cindex tracepoint variables | |
9981 | @cindex convenience variables for tracepoints | |
9982 | ||
9983 | @table @code | |
9984 | @vindex $trace_frame | |
9985 | @item (int) $trace_frame | |
9986 | The current trace snapshot (a.k.a.@: @dfn{frame}) number, or -1 if no | |
9987 | snapshot is selected. | |
9988 | ||
9989 | @vindex $tracepoint | |
9990 | @item (int) $tracepoint | |
9991 | The tracepoint for the current trace snapshot. | |
9992 | ||
9993 | @vindex $trace_line | |
9994 | @item (int) $trace_line | |
9995 | The line number for the current trace snapshot. | |
9996 | ||
9997 | @vindex $trace_file | |
9998 | @item (char []) $trace_file | |
9999 | The source file for the current trace snapshot. | |
10000 | ||
10001 | @vindex $trace_func | |
10002 | @item (char []) $trace_func | |
10003 | The name of the function containing @code{$tracepoint}. | |
10004 | @end table | |
10005 | ||
10006 | Note: @code{$trace_file} is not suitable for use in @code{printf}, | |
10007 | use @code{output} instead. | |
10008 | ||
10009 | Here's a simple example of using these convenience variables for | |
10010 | stepping through all the trace snapshots and printing some of their | |
f61e138d SS |
10011 | data. Note that these are not the same as trace state variables, |
10012 | which are managed by the target. | |
b37052ae EZ |
10013 | |
10014 | @smallexample | |
10015 | (@value{GDBP}) @b{tfind start} | |
10016 | ||
10017 | (@value{GDBP}) @b{while $trace_frame != -1} | |
10018 | > output $trace_file | |
10019 | > printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint | |
10020 | > tfind | |
10021 | > end | |
10022 | @end smallexample | |
10023 | ||
df0cd8c5 JB |
10024 | @node Overlays |
10025 | @chapter Debugging Programs That Use Overlays | |
10026 | @cindex overlays | |
10027 | ||
10028 | If your program is too large to fit completely in your target system's | |
10029 | memory, you can sometimes use @dfn{overlays} to work around this | |
10030 | problem. @value{GDBN} provides some support for debugging programs that | |
10031 | use overlays. | |
10032 | ||
10033 | @menu | |
10034 | * How Overlays Work:: A general explanation of overlays. | |
10035 | * Overlay Commands:: Managing overlays in @value{GDBN}. | |
10036 | * Automatic Overlay Debugging:: @value{GDBN} can find out which overlays are | |
10037 | mapped by asking the inferior. | |
10038 | * Overlay Sample Program:: A sample program using overlays. | |
10039 | @end menu | |
10040 | ||
10041 | @node How Overlays Work | |
10042 | @section How Overlays Work | |
10043 | @cindex mapped overlays | |
10044 | @cindex unmapped overlays | |
10045 | @cindex load address, overlay's | |
10046 | @cindex mapped address | |
10047 | @cindex overlay area | |
10048 | ||
10049 | Suppose you have a computer whose instruction address space is only 64 | |
10050 | kilobytes long, but which has much more memory which can be accessed by | |
10051 | other means: special instructions, segment registers, or memory | |
10052 | management hardware, for example. Suppose further that you want to | |
10053 | adapt a program which is larger than 64 kilobytes to run on this system. | |
10054 | ||
10055 | One solution is to identify modules of your program which are relatively | |
10056 | independent, and need not call each other directly; call these modules | |
10057 | @dfn{overlays}. Separate the overlays from the main program, and place | |
10058 | their machine code in the larger memory. Place your main program in | |
10059 | instruction memory, but leave at least enough space there to hold the | |
10060 | largest overlay as well. | |
10061 | ||
10062 | Now, to call a function located in an overlay, you must first copy that | |
10063 | overlay's machine code from the large memory into the space set aside | |
10064 | for it in the instruction memory, and then jump to its entry point | |
10065 | there. | |
10066 | ||
c928edc0 AC |
10067 | @c NB: In the below the mapped area's size is greater or equal to the |
10068 | @c size of all overlays. This is intentional to remind the developer | |
10069 | @c that overlays don't necessarily need to be the same size. | |
10070 | ||
474c8240 | 10071 | @smallexample |
df0cd8c5 | 10072 | @group |
c928edc0 AC |
10073 | Data Instruction Larger |
10074 | Address Space Address Space Address Space | |
10075 | +-----------+ +-----------+ +-----------+ | |
10076 | | | | | | | | |
10077 | +-----------+ +-----------+ +-----------+<-- overlay 1 | |
10078 | | program | | main | .----| overlay 1 | load address | |
10079 | | variables | | program | | +-----------+ | |
10080 | | and heap | | | | | | | |
10081 | +-----------+ | | | +-----------+<-- overlay 2 | |
10082 | | | +-----------+ | | | load address | |
10083 | +-----------+ | | | .-| overlay 2 | | |
10084 | | | | | | | | |
10085 | mapped --->+-----------+ | | +-----------+ | |
10086 | address | | | | | | | |
10087 | | overlay | <-' | | | | |
10088 | | area | <---' +-----------+<-- overlay 3 | |
10089 | | | <---. | | load address | |
10090 | +-----------+ `--| overlay 3 | | |
10091 | | | | | | |
10092 | +-----------+ | | | |
10093 | +-----------+ | |
10094 | | | | |
10095 | +-----------+ | |
10096 | ||
10097 | @anchor{A code overlay}A code overlay | |
df0cd8c5 | 10098 | @end group |
474c8240 | 10099 | @end smallexample |
df0cd8c5 | 10100 | |
c928edc0 AC |
10101 | The diagram (@pxref{A code overlay}) shows a system with separate data |
10102 | and instruction address spaces. To map an overlay, the program copies | |
10103 | its code from the larger address space to the instruction address space. | |
10104 | Since the overlays shown here all use the same mapped address, only one | |
10105 | may be mapped at a time. For a system with a single address space for | |
10106 | data and instructions, the diagram would be similar, except that the | |
10107 | program variables and heap would share an address space with the main | |
10108 | program and the overlay area. | |
df0cd8c5 JB |
10109 | |
10110 | An overlay loaded into instruction memory and ready for use is called a | |
10111 | @dfn{mapped} overlay; its @dfn{mapped address} is its address in the | |
10112 | instruction memory. An overlay not present (or only partially present) | |
10113 | in instruction memory is called @dfn{unmapped}; its @dfn{load address} | |
10114 | is its address in the larger memory. The mapped address is also called | |
10115 | the @dfn{virtual memory address}, or @dfn{VMA}; the load address is also | |
10116 | called the @dfn{load memory address}, or @dfn{LMA}. | |
10117 | ||
10118 | Unfortunately, overlays are not a completely transparent way to adapt a | |
10119 | program to limited instruction memory. They introduce a new set of | |
10120 | global constraints you must keep in mind as you design your program: | |
10121 | ||
10122 | @itemize @bullet | |
10123 | ||
10124 | @item | |
10125 | Before calling or returning to a function in an overlay, your program | |
10126 | must make sure that overlay is actually mapped. Otherwise, the call or | |
10127 | return will transfer control to the right address, but in the wrong | |
10128 | overlay, and your program will probably crash. | |
10129 | ||
10130 | @item | |
10131 | If the process of mapping an overlay is expensive on your system, you | |
10132 | will need to choose your overlays carefully to minimize their effect on | |
10133 | your program's performance. | |
10134 | ||
10135 | @item | |
10136 | The executable file you load onto your system must contain each | |
10137 | overlay's instructions, appearing at the overlay's load address, not its | |
10138 | mapped address. However, each overlay's instructions must be relocated | |
10139 | and its symbols defined as if the overlay were at its mapped address. | |
10140 | You can use GNU linker scripts to specify different load and relocation | |
10141 | addresses for pieces of your program; see @ref{Overlay Description,,, | |
10142 | ld.info, Using ld: the GNU linker}. | |
10143 | ||
10144 | @item | |
10145 | The procedure for loading executable files onto your system must be able | |
10146 | to load their contents into the larger address space as well as the | |
10147 | instruction and data spaces. | |
10148 | ||
10149 | @end itemize | |
10150 | ||
10151 | The overlay system described above is rather simple, and could be | |
10152 | improved in many ways: | |
10153 | ||
10154 | @itemize @bullet | |
10155 | ||
10156 | @item | |
10157 | If your system has suitable bank switch registers or memory management | |
10158 | hardware, you could use those facilities to make an overlay's load area | |
10159 | contents simply appear at their mapped address in instruction space. | |
10160 | This would probably be faster than copying the overlay to its mapped | |
10161 | area in the usual way. | |
10162 | ||
10163 | @item | |
10164 | If your overlays are small enough, you could set aside more than one | |
10165 | overlay area, and have more than one overlay mapped at a time. | |
10166 | ||
10167 | @item | |
10168 | You can use overlays to manage data, as well as instructions. In | |
10169 | general, data overlays are even less transparent to your design than | |
10170 | code overlays: whereas code overlays only require care when you call or | |
10171 | return to functions, data overlays require care every time you access | |
10172 | the data. Also, if you change the contents of a data overlay, you | |
10173 | must copy its contents back out to its load address before you can copy a | |
10174 | different data overlay into the same mapped area. | |
10175 | ||
10176 | @end itemize | |
10177 | ||
10178 | ||
10179 | @node Overlay Commands | |
10180 | @section Overlay Commands | |
10181 | ||
10182 | To use @value{GDBN}'s overlay support, each overlay in your program must | |
10183 | correspond to a separate section of the executable file. The section's | |
10184 | virtual memory address and load memory address must be the overlay's | |
10185 | mapped and load addresses. Identifying overlays with sections allows | |
10186 | @value{GDBN} to determine the appropriate address of a function or | |
10187 | variable, depending on whether the overlay is mapped or not. | |
10188 | ||
10189 | @value{GDBN}'s overlay commands all start with the word @code{overlay}; | |
10190 | you can abbreviate this as @code{ov} or @code{ovly}. The commands are: | |
10191 | ||
10192 | @table @code | |
10193 | @item overlay off | |
4644b6e3 | 10194 | @kindex overlay |
df0cd8c5 JB |
10195 | Disable @value{GDBN}'s overlay support. When overlay support is |
10196 | disabled, @value{GDBN} assumes that all functions and variables are | |
10197 | always present at their mapped addresses. By default, @value{GDBN}'s | |
10198 | overlay support is disabled. | |
10199 | ||
10200 | @item overlay manual | |
df0cd8c5 JB |
10201 | @cindex manual overlay debugging |
10202 | Enable @dfn{manual} overlay debugging. In this mode, @value{GDBN} | |
10203 | relies on you to tell it which overlays are mapped, and which are not, | |
10204 | using the @code{overlay map-overlay} and @code{overlay unmap-overlay} | |
10205 | commands described below. | |
10206 | ||
10207 | @item overlay map-overlay @var{overlay} | |
10208 | @itemx overlay map @var{overlay} | |
df0cd8c5 JB |
10209 | @cindex map an overlay |
10210 | Tell @value{GDBN} that @var{overlay} is now mapped; @var{overlay} must | |
10211 | be the name of the object file section containing the overlay. When an | |
10212 | overlay is mapped, @value{GDBN} assumes it can find the overlay's | |
10213 | functions and variables at their mapped addresses. @value{GDBN} assumes | |
10214 | that any other overlays whose mapped ranges overlap that of | |
10215 | @var{overlay} are now unmapped. | |
10216 | ||
10217 | @item overlay unmap-overlay @var{overlay} | |
10218 | @itemx overlay unmap @var{overlay} | |
df0cd8c5 JB |
10219 | @cindex unmap an overlay |
10220 | Tell @value{GDBN} that @var{overlay} is no longer mapped; @var{overlay} | |
10221 | must be the name of the object file section containing the overlay. | |
10222 | When an overlay is unmapped, @value{GDBN} assumes it can find the | |
10223 | overlay's functions and variables at their load addresses. | |
10224 | ||
10225 | @item overlay auto | |
df0cd8c5 JB |
10226 | Enable @dfn{automatic} overlay debugging. In this mode, @value{GDBN} |
10227 | consults a data structure the overlay manager maintains in the inferior | |
10228 | to see which overlays are mapped. For details, see @ref{Automatic | |
10229 | Overlay Debugging}. | |
10230 | ||
10231 | @item overlay load-target | |
10232 | @itemx overlay load | |
df0cd8c5 JB |
10233 | @cindex reloading the overlay table |
10234 | Re-read the overlay table from the inferior. Normally, @value{GDBN} | |
10235 | re-reads the table @value{GDBN} automatically each time the inferior | |
10236 | stops, so this command should only be necessary if you have changed the | |
10237 | overlay mapping yourself using @value{GDBN}. This command is only | |
10238 | useful when using automatic overlay debugging. | |
10239 | ||
10240 | @item overlay list-overlays | |
10241 | @itemx overlay list | |
10242 | @cindex listing mapped overlays | |
10243 | Display a list of the overlays currently mapped, along with their mapped | |
10244 | addresses, load addresses, and sizes. | |
10245 | ||
10246 | @end table | |
10247 | ||
10248 | Normally, when @value{GDBN} prints a code address, it includes the name | |
10249 | of the function the address falls in: | |
10250 | ||
474c8240 | 10251 | @smallexample |
f7dc1244 | 10252 | (@value{GDBP}) print main |
df0cd8c5 | 10253 | $3 = @{int ()@} 0x11a0 <main> |
474c8240 | 10254 | @end smallexample |
df0cd8c5 JB |
10255 | @noindent |
10256 | When overlay debugging is enabled, @value{GDBN} recognizes code in | |
10257 | unmapped overlays, and prints the names of unmapped functions with | |
10258 | asterisks around them. For example, if @code{foo} is a function in an | |
10259 | unmapped overlay, @value{GDBN} prints it this way: | |
10260 | ||
474c8240 | 10261 | @smallexample |
f7dc1244 | 10262 | (@value{GDBP}) overlay list |
df0cd8c5 | 10263 | No sections are mapped. |
f7dc1244 | 10264 | (@value{GDBP}) print foo |
df0cd8c5 | 10265 | $5 = @{int (int)@} 0x100000 <*foo*> |
474c8240 | 10266 | @end smallexample |
df0cd8c5 JB |
10267 | @noindent |
10268 | When @code{foo}'s overlay is mapped, @value{GDBN} prints the function's | |
10269 | name normally: | |
10270 | ||
474c8240 | 10271 | @smallexample |
f7dc1244 | 10272 | (@value{GDBP}) overlay list |
b383017d | 10273 | Section .ov.foo.text, loaded at 0x100000 - 0x100034, |
df0cd8c5 | 10274 | mapped at 0x1016 - 0x104a |
f7dc1244 | 10275 | (@value{GDBP}) print foo |
df0cd8c5 | 10276 | $6 = @{int (int)@} 0x1016 <foo> |
474c8240 | 10277 | @end smallexample |
df0cd8c5 JB |
10278 | |
10279 | When overlay debugging is enabled, @value{GDBN} can find the correct | |
10280 | address for functions and variables in an overlay, whether or not the | |
10281 | overlay is mapped. This allows most @value{GDBN} commands, like | |
10282 | @code{break} and @code{disassemble}, to work normally, even on unmapped | |
10283 | code. However, @value{GDBN}'s breakpoint support has some limitations: | |
10284 | ||
10285 | @itemize @bullet | |
10286 | @item | |
10287 | @cindex breakpoints in overlays | |
10288 | @cindex overlays, setting breakpoints in | |
10289 | You can set breakpoints in functions in unmapped overlays, as long as | |
10290 | @value{GDBN} can write to the overlay at its load address. | |
10291 | @item | |
10292 | @value{GDBN} can not set hardware or simulator-based breakpoints in | |
10293 | unmapped overlays. However, if you set a breakpoint at the end of your | |
10294 | overlay manager (and tell @value{GDBN} which overlays are now mapped, if | |
10295 | you are using manual overlay management), @value{GDBN} will re-set its | |
10296 | breakpoints properly. | |
10297 | @end itemize | |
10298 | ||
10299 | ||
10300 | @node Automatic Overlay Debugging | |
10301 | @section Automatic Overlay Debugging | |
10302 | @cindex automatic overlay debugging | |
10303 | ||
10304 | @value{GDBN} can automatically track which overlays are mapped and which | |
10305 | are not, given some simple co-operation from the overlay manager in the | |
10306 | inferior. If you enable automatic overlay debugging with the | |
10307 | @code{overlay auto} command (@pxref{Overlay Commands}), @value{GDBN} | |
10308 | looks in the inferior's memory for certain variables describing the | |
10309 | current state of the overlays. | |
10310 | ||
10311 | Here are the variables your overlay manager must define to support | |
10312 | @value{GDBN}'s automatic overlay debugging: | |
10313 | ||
10314 | @table @asis | |
10315 | ||
10316 | @item @code{_ovly_table}: | |
10317 | This variable must be an array of the following structures: | |
10318 | ||
474c8240 | 10319 | @smallexample |
df0cd8c5 JB |
10320 | struct |
10321 | @{ | |
10322 | /* The overlay's mapped address. */ | |
10323 | unsigned long vma; | |
10324 | ||
10325 | /* The size of the overlay, in bytes. */ | |
10326 | unsigned long size; | |
10327 | ||
10328 | /* The overlay's load address. */ | |
10329 | unsigned long lma; | |
10330 | ||
10331 | /* Non-zero if the overlay is currently mapped; | |
10332 | zero otherwise. */ | |
10333 | unsigned long mapped; | |
10334 | @} | |
474c8240 | 10335 | @end smallexample |
df0cd8c5 JB |
10336 | |
10337 | @item @code{_novlys}: | |
10338 | This variable must be a four-byte signed integer, holding the total | |
10339 | number of elements in @code{_ovly_table}. | |
10340 | ||
10341 | @end table | |
10342 | ||
10343 | To decide whether a particular overlay is mapped or not, @value{GDBN} | |
10344 | looks for an entry in @w{@code{_ovly_table}} whose @code{vma} and | |
10345 | @code{lma} members equal the VMA and LMA of the overlay's section in the | |
10346 | executable file. When @value{GDBN} finds a matching entry, it consults | |
10347 | the entry's @code{mapped} member to determine whether the overlay is | |
10348 | currently mapped. | |
10349 | ||
81d46470 | 10350 | In addition, your overlay manager may define a function called |
def71bfa | 10351 | @code{_ovly_debug_event}. If this function is defined, @value{GDBN} |
81d46470 MS |
10352 | will silently set a breakpoint there. If the overlay manager then |
10353 | calls this function whenever it has changed the overlay table, this | |
10354 | will enable @value{GDBN} to accurately keep track of which overlays | |
10355 | are in program memory, and update any breakpoints that may be set | |
b383017d | 10356 | in overlays. This will allow breakpoints to work even if the |
81d46470 MS |
10357 | overlays are kept in ROM or other non-writable memory while they |
10358 | are not being executed. | |
df0cd8c5 JB |
10359 | |
10360 | @node Overlay Sample Program | |
10361 | @section Overlay Sample Program | |
10362 | @cindex overlay example program | |
10363 | ||
10364 | When linking a program which uses overlays, you must place the overlays | |
10365 | at their load addresses, while relocating them to run at their mapped | |
10366 | addresses. To do this, you must write a linker script (@pxref{Overlay | |
10367 | Description,,, ld.info, Using ld: the GNU linker}). Unfortunately, | |
10368 | since linker scripts are specific to a particular host system, target | |
10369 | architecture, and target memory layout, this manual cannot provide | |
10370 | portable sample code demonstrating @value{GDBN}'s overlay support. | |
10371 | ||
10372 | However, the @value{GDBN} source distribution does contain an overlaid | |
10373 | program, with linker scripts for a few systems, as part of its test | |
10374 | suite. The program consists of the following files from | |
10375 | @file{gdb/testsuite/gdb.base}: | |
10376 | ||
10377 | @table @file | |
10378 | @item overlays.c | |
10379 | The main program file. | |
10380 | @item ovlymgr.c | |
10381 | A simple overlay manager, used by @file{overlays.c}. | |
10382 | @item foo.c | |
10383 | @itemx bar.c | |
10384 | @itemx baz.c | |
10385 | @itemx grbx.c | |
10386 | Overlay modules, loaded and used by @file{overlays.c}. | |
10387 | @item d10v.ld | |
10388 | @itemx m32r.ld | |
10389 | Linker scripts for linking the test program on the @code{d10v-elf} | |
10390 | and @code{m32r-elf} targets. | |
10391 | @end table | |
10392 | ||
10393 | You can build the test program using the @code{d10v-elf} GCC | |
10394 | cross-compiler like this: | |
10395 | ||
474c8240 | 10396 | @smallexample |
df0cd8c5 JB |
10397 | $ d10v-elf-gcc -g -c overlays.c |
10398 | $ d10v-elf-gcc -g -c ovlymgr.c | |
10399 | $ d10v-elf-gcc -g -c foo.c | |
10400 | $ d10v-elf-gcc -g -c bar.c | |
10401 | $ d10v-elf-gcc -g -c baz.c | |
10402 | $ d10v-elf-gcc -g -c grbx.c | |
10403 | $ d10v-elf-gcc -g overlays.o ovlymgr.o foo.o bar.o \ | |
10404 | baz.o grbx.o -Wl,-Td10v.ld -o overlays | |
474c8240 | 10405 | @end smallexample |
df0cd8c5 JB |
10406 | |
10407 | The build process is identical for any other architecture, except that | |
10408 | you must substitute the appropriate compiler and linker script for the | |
10409 | target system for @code{d10v-elf-gcc} and @code{d10v.ld}. | |
10410 | ||
10411 | ||
6d2ebf8b | 10412 | @node Languages |
c906108c SS |
10413 | @chapter Using @value{GDBN} with Different Languages |
10414 | @cindex languages | |
10415 | ||
c906108c SS |
10416 | Although programming languages generally have common aspects, they are |
10417 | rarely expressed in the same manner. For instance, in ANSI C, | |
10418 | dereferencing a pointer @code{p} is accomplished by @code{*p}, but in | |
10419 | Modula-2, it is accomplished by @code{p^}. Values can also be | |
5d161b24 | 10420 | represented (and displayed) differently. Hex numbers in C appear as |
c906108c | 10421 | @samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}. |
c906108c SS |
10422 | |
10423 | @cindex working language | |
10424 | Language-specific information is built into @value{GDBN} for some languages, | |
10425 | allowing you to express operations like the above in your program's | |
10426 | native language, and allowing @value{GDBN} to output values in a manner | |
10427 | consistent with the syntax of your program's native language. The | |
10428 | language you use to build expressions is called the @dfn{working | |
10429 | language}. | |
10430 | ||
10431 | @menu | |
10432 | * Setting:: Switching between source languages | |
10433 | * Show:: Displaying the language | |
c906108c | 10434 | * Checks:: Type and range checks |
79a6e687 BW |
10435 | * Supported Languages:: Supported languages |
10436 | * Unsupported Languages:: Unsupported languages | |
c906108c SS |
10437 | @end menu |
10438 | ||
6d2ebf8b | 10439 | @node Setting |
79a6e687 | 10440 | @section Switching Between Source Languages |
c906108c SS |
10441 | |
10442 | There are two ways to control the working language---either have @value{GDBN} | |
10443 | set it automatically, or select it manually yourself. You can use the | |
10444 | @code{set language} command for either purpose. On startup, @value{GDBN} | |
10445 | defaults to setting the language automatically. The working language is | |
10446 | used to determine how expressions you type are interpreted, how values | |
10447 | are printed, etc. | |
10448 | ||
10449 | In addition to the working language, every source file that | |
10450 | @value{GDBN} knows about has its own working language. For some object | |
10451 | file formats, the compiler might indicate which language a particular | |
10452 | source file is in. However, most of the time @value{GDBN} infers the | |
10453 | language from the name of the file. The language of a source file | |
b37052ae | 10454 | controls whether C@t{++} names are demangled---this way @code{backtrace} can |
c906108c | 10455 | show each frame appropriately for its own language. There is no way to |
d4f3574e SS |
10456 | set the language of a source file from within @value{GDBN}, but you can |
10457 | set the language associated with a filename extension. @xref{Show, , | |
79a6e687 | 10458 | Displaying the Language}. |
c906108c SS |
10459 | |
10460 | This is most commonly a problem when you use a program, such | |
5d161b24 | 10461 | as @code{cfront} or @code{f2c}, that generates C but is written in |
c906108c SS |
10462 | another language. In that case, make the |
10463 | program use @code{#line} directives in its C output; that way | |
10464 | @value{GDBN} will know the correct language of the source code of the original | |
10465 | program, and will display that source code, not the generated C code. | |
10466 | ||
10467 | @menu | |
10468 | * Filenames:: Filename extensions and languages. | |
10469 | * Manually:: Setting the working language manually | |
10470 | * Automatically:: Having @value{GDBN} infer the source language | |
10471 | @end menu | |
10472 | ||
6d2ebf8b | 10473 | @node Filenames |
79a6e687 | 10474 | @subsection List of Filename Extensions and Languages |
c906108c SS |
10475 | |
10476 | If a source file name ends in one of the following extensions, then | |
10477 | @value{GDBN} infers that its language is the one indicated. | |
10478 | ||
10479 | @table @file | |
e07c999f PH |
10480 | @item .ada |
10481 | @itemx .ads | |
10482 | @itemx .adb | |
10483 | @itemx .a | |
10484 | Ada source file. | |
c906108c SS |
10485 | |
10486 | @item .c | |
10487 | C source file | |
10488 | ||
10489 | @item .C | |
10490 | @itemx .cc | |
10491 | @itemx .cp | |
10492 | @itemx .cpp | |
10493 | @itemx .cxx | |
10494 | @itemx .c++ | |
b37052ae | 10495 | C@t{++} source file |
c906108c | 10496 | |
b37303ee AF |
10497 | @item .m |
10498 | Objective-C source file | |
10499 | ||
c906108c SS |
10500 | @item .f |
10501 | @itemx .F | |
10502 | Fortran source file | |
10503 | ||
c906108c SS |
10504 | @item .mod |
10505 | Modula-2 source file | |
c906108c SS |
10506 | |
10507 | @item .s | |
10508 | @itemx .S | |
10509 | Assembler source file. This actually behaves almost like C, but | |
10510 | @value{GDBN} does not skip over function prologues when stepping. | |
10511 | @end table | |
10512 | ||
10513 | In addition, you may set the language associated with a filename | |
79a6e687 | 10514 | extension. @xref{Show, , Displaying the Language}. |
c906108c | 10515 | |
6d2ebf8b | 10516 | @node Manually |
79a6e687 | 10517 | @subsection Setting the Working Language |
c906108c SS |
10518 | |
10519 | If you allow @value{GDBN} to set the language automatically, | |
10520 | expressions are interpreted the same way in your debugging session and | |
10521 | your program. | |
10522 | ||
10523 | @kindex set language | |
10524 | If you wish, you may set the language manually. To do this, issue the | |
10525 | command @samp{set language @var{lang}}, where @var{lang} is the name of | |
5d161b24 | 10526 | a language, such as |
c906108c | 10527 | @code{c} or @code{modula-2}. |
c906108c SS |
10528 | For a list of the supported languages, type @samp{set language}. |
10529 | ||
c906108c SS |
10530 | Setting the language manually prevents @value{GDBN} from updating the working |
10531 | language automatically. This can lead to confusion if you try | |
10532 | to debug a program when the working language is not the same as the | |
10533 | source language, when an expression is acceptable to both | |
10534 | languages---but means different things. For instance, if the current | |
10535 | source file were written in C, and @value{GDBN} was parsing Modula-2, a | |
10536 | command such as: | |
10537 | ||
474c8240 | 10538 | @smallexample |
c906108c | 10539 | print a = b + c |
474c8240 | 10540 | @end smallexample |
c906108c SS |
10541 | |
10542 | @noindent | |
10543 | might not have the effect you intended. In C, this means to add | |
10544 | @code{b} and @code{c} and place the result in @code{a}. The result | |
10545 | printed would be the value of @code{a}. In Modula-2, this means to compare | |
10546 | @code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value. | |
c906108c | 10547 | |
6d2ebf8b | 10548 | @node Automatically |
79a6e687 | 10549 | @subsection Having @value{GDBN} Infer the Source Language |
c906108c SS |
10550 | |
10551 | To have @value{GDBN} set the working language automatically, use | |
10552 | @samp{set language local} or @samp{set language auto}. @value{GDBN} | |
10553 | then infers the working language. That is, when your program stops in a | |
10554 | frame (usually by encountering a breakpoint), @value{GDBN} sets the | |
10555 | working language to the language recorded for the function in that | |
10556 | frame. If the language for a frame is unknown (that is, if the function | |
10557 | or block corresponding to the frame was defined in a source file that | |
10558 | does not have a recognized extension), the current working language is | |
10559 | not changed, and @value{GDBN} issues a warning. | |
10560 | ||
10561 | This may not seem necessary for most programs, which are written | |
10562 | entirely in one source language. However, program modules and libraries | |
10563 | written in one source language can be used by a main program written in | |
10564 | a different source language. Using @samp{set language auto} in this | |
10565 | case frees you from having to set the working language manually. | |
10566 | ||
6d2ebf8b | 10567 | @node Show |
79a6e687 | 10568 | @section Displaying the Language |
c906108c SS |
10569 | |
10570 | The following commands help you find out which language is the | |
10571 | working language, and also what language source files were written in. | |
10572 | ||
c906108c SS |
10573 | @table @code |
10574 | @item show language | |
9c16f35a | 10575 | @kindex show language |
c906108c SS |
10576 | Display the current working language. This is the |
10577 | language you can use with commands such as @code{print} to | |
10578 | build and compute expressions that may involve variables in your program. | |
10579 | ||
10580 | @item info frame | |
4644b6e3 | 10581 | @kindex info frame@r{, show the source language} |
5d161b24 | 10582 | Display the source language for this frame. This language becomes the |
c906108c | 10583 | working language if you use an identifier from this frame. |
79a6e687 | 10584 | @xref{Frame Info, ,Information about a Frame}, to identify the other |
c906108c SS |
10585 | information listed here. |
10586 | ||
10587 | @item info source | |
4644b6e3 | 10588 | @kindex info source@r{, show the source language} |
c906108c | 10589 | Display the source language of this source file. |
5d161b24 | 10590 | @xref{Symbols, ,Examining the Symbol Table}, to identify the other |
c906108c SS |
10591 | information listed here. |
10592 | @end table | |
10593 | ||
10594 | In unusual circumstances, you may have source files with extensions | |
10595 | not in the standard list. You can then set the extension associated | |
10596 | with a language explicitly: | |
10597 | ||
c906108c | 10598 | @table @code |
09d4efe1 | 10599 | @item set extension-language @var{ext} @var{language} |
9c16f35a | 10600 | @kindex set extension-language |
09d4efe1 EZ |
10601 | Tell @value{GDBN} that source files with extension @var{ext} are to be |
10602 | assumed as written in the source language @var{language}. | |
c906108c SS |
10603 | |
10604 | @item info extensions | |
9c16f35a | 10605 | @kindex info extensions |
c906108c SS |
10606 | List all the filename extensions and the associated languages. |
10607 | @end table | |
10608 | ||
6d2ebf8b | 10609 | @node Checks |
79a6e687 | 10610 | @section Type and Range Checking |
c906108c SS |
10611 | |
10612 | @quotation | |
10613 | @emph{Warning:} In this release, the @value{GDBN} commands for type and range | |
10614 | checking are included, but they do not yet have any effect. This | |
10615 | section documents the intended facilities. | |
10616 | @end quotation | |
10617 | @c FIXME remove warning when type/range code added | |
10618 | ||
10619 | Some languages are designed to guard you against making seemingly common | |
10620 | errors through a series of compile- and run-time checks. These include | |
10621 | checking the type of arguments to functions and operators, and making | |
10622 | sure mathematical overflows are caught at run time. Checks such as | |
10623 | these help to ensure a program's correctness once it has been compiled | |
10624 | by eliminating type mismatches, and providing active checks for range | |
10625 | errors when your program is running. | |
10626 | ||
10627 | @value{GDBN} can check for conditions like the above if you wish. | |
9c16f35a EZ |
10628 | Although @value{GDBN} does not check the statements in your program, |
10629 | it can check expressions entered directly into @value{GDBN} for | |
10630 | evaluation via the @code{print} command, for example. As with the | |
10631 | working language, @value{GDBN} can also decide whether or not to check | |
10632 | automatically based on your program's source language. | |
79a6e687 | 10633 | @xref{Supported Languages, ,Supported Languages}, for the default |
9c16f35a | 10634 | settings of supported languages. |
c906108c SS |
10635 | |
10636 | @menu | |
10637 | * Type Checking:: An overview of type checking | |
10638 | * Range Checking:: An overview of range checking | |
10639 | @end menu | |
10640 | ||
10641 | @cindex type checking | |
10642 | @cindex checks, type | |
6d2ebf8b | 10643 | @node Type Checking |
79a6e687 | 10644 | @subsection An Overview of Type Checking |
c906108c SS |
10645 | |
10646 | Some languages, such as Modula-2, are strongly typed, meaning that the | |
10647 | arguments to operators and functions have to be of the correct type, | |
10648 | otherwise an error occurs. These checks prevent type mismatch | |
10649 | errors from ever causing any run-time problems. For example, | |
10650 | ||
10651 | @smallexample | |
10652 | 1 + 2 @result{} 3 | |
10653 | @exdent but | |
10654 | @error{} 1 + 2.3 | |
10655 | @end smallexample | |
10656 | ||
10657 | The second example fails because the @code{CARDINAL} 1 is not | |
10658 | type-compatible with the @code{REAL} 2.3. | |
10659 | ||
5d161b24 DB |
10660 | For the expressions you use in @value{GDBN} commands, you can tell the |
10661 | @value{GDBN} type checker to skip checking; | |
10662 | to treat any mismatches as errors and abandon the expression; | |
10663 | or to only issue warnings when type mismatches occur, | |
c906108c SS |
10664 | but evaluate the expression anyway. When you choose the last of |
10665 | these, @value{GDBN} evaluates expressions like the second example above, but | |
10666 | also issues a warning. | |
10667 | ||
5d161b24 DB |
10668 | Even if you turn type checking off, there may be other reasons |
10669 | related to type that prevent @value{GDBN} from evaluating an expression. | |
10670 | For instance, @value{GDBN} does not know how to add an @code{int} and | |
10671 | a @code{struct foo}. These particular type errors have nothing to do | |
10672 | with the language in use, and usually arise from expressions, such as | |
c906108c SS |
10673 | the one described above, which make little sense to evaluate anyway. |
10674 | ||
10675 | Each language defines to what degree it is strict about type. For | |
10676 | instance, both Modula-2 and C require the arguments to arithmetical | |
10677 | operators to be numbers. In C, enumerated types and pointers can be | |
10678 | represented as numbers, so that they are valid arguments to mathematical | |
79a6e687 | 10679 | operators. @xref{Supported Languages, ,Supported Languages}, for further |
c906108c SS |
10680 | details on specific languages. |
10681 | ||
10682 | @value{GDBN} provides some additional commands for controlling the type checker: | |
10683 | ||
c906108c SS |
10684 | @kindex set check type |
10685 | @kindex show check type | |
10686 | @table @code | |
10687 | @item set check type auto | |
10688 | Set type checking on or off based on the current working language. | |
79a6e687 | 10689 | @xref{Supported Languages, ,Supported Languages}, for the default settings for |
c906108c SS |
10690 | each language. |
10691 | ||
10692 | @item set check type on | |
10693 | @itemx set check type off | |
10694 | Set type checking on or off, overriding the default setting for the | |
10695 | current working language. Issue a warning if the setting does not | |
10696 | match the language default. If any type mismatches occur in | |
d4f3574e | 10697 | evaluating an expression while type checking is on, @value{GDBN} prints a |
c906108c SS |
10698 | message and aborts evaluation of the expression. |
10699 | ||
10700 | @item set check type warn | |
10701 | Cause the type checker to issue warnings, but to always attempt to | |
10702 | evaluate the expression. Evaluating the expression may still | |
10703 | be impossible for other reasons. For example, @value{GDBN} cannot add | |
10704 | numbers and structures. | |
10705 | ||
10706 | @item show type | |
5d161b24 | 10707 | Show the current setting of the type checker, and whether or not @value{GDBN} |
c906108c SS |
10708 | is setting it automatically. |
10709 | @end table | |
10710 | ||
10711 | @cindex range checking | |
10712 | @cindex checks, range | |
6d2ebf8b | 10713 | @node Range Checking |
79a6e687 | 10714 | @subsection An Overview of Range Checking |
c906108c SS |
10715 | |
10716 | In some languages (such as Modula-2), it is an error to exceed the | |
10717 | bounds of a type; this is enforced with run-time checks. Such range | |
10718 | checking is meant to ensure program correctness by making sure | |
10719 | computations do not overflow, or indices on an array element access do | |
10720 | not exceed the bounds of the array. | |
10721 | ||
10722 | For expressions you use in @value{GDBN} commands, you can tell | |
10723 | @value{GDBN} to treat range errors in one of three ways: ignore them, | |
10724 | always treat them as errors and abandon the expression, or issue | |
10725 | warnings but evaluate the expression anyway. | |
10726 | ||
10727 | A range error can result from numerical overflow, from exceeding an | |
10728 | array index bound, or when you type a constant that is not a member | |
10729 | of any type. Some languages, however, do not treat overflows as an | |
10730 | error. In many implementations of C, mathematical overflow causes the | |
10731 | result to ``wrap around'' to lower values---for example, if @var{m} is | |
10732 | the largest integer value, and @var{s} is the smallest, then | |
10733 | ||
474c8240 | 10734 | @smallexample |
c906108c | 10735 | @var{m} + 1 @result{} @var{s} |
474c8240 | 10736 | @end smallexample |
c906108c SS |
10737 | |
10738 | This, too, is specific to individual languages, and in some cases | |
79a6e687 BW |
10739 | specific to individual compilers or machines. @xref{Supported Languages, , |
10740 | Supported Languages}, for further details on specific languages. | |
c906108c SS |
10741 | |
10742 | @value{GDBN} provides some additional commands for controlling the range checker: | |
10743 | ||
c906108c SS |
10744 | @kindex set check range |
10745 | @kindex show check range | |
10746 | @table @code | |
10747 | @item set check range auto | |
10748 | Set range checking on or off based on the current working language. | |
79a6e687 | 10749 | @xref{Supported Languages, ,Supported Languages}, for the default settings for |
c906108c SS |
10750 | each language. |
10751 | ||
10752 | @item set check range on | |
10753 | @itemx set check range off | |
10754 | Set range checking on or off, overriding the default setting for the | |
10755 | current working language. A warning is issued if the setting does not | |
c3f6f71d JM |
10756 | match the language default. If a range error occurs and range checking is on, |
10757 | then a message is printed and evaluation of the expression is aborted. | |
c906108c SS |
10758 | |
10759 | @item set check range warn | |
10760 | Output messages when the @value{GDBN} range checker detects a range error, | |
10761 | but attempt to evaluate the expression anyway. Evaluating the | |
10762 | expression may still be impossible for other reasons, such as accessing | |
10763 | memory that the process does not own (a typical example from many Unix | |
10764 | systems). | |
10765 | ||
10766 | @item show range | |
10767 | Show the current setting of the range checker, and whether or not it is | |
10768 | being set automatically by @value{GDBN}. | |
10769 | @end table | |
c906108c | 10770 | |
79a6e687 BW |
10771 | @node Supported Languages |
10772 | @section Supported Languages | |
c906108c | 10773 | |
9c16f35a EZ |
10774 | @value{GDBN} supports C, C@t{++}, Objective-C, Fortran, Java, Pascal, |
10775 | assembly, Modula-2, and Ada. | |
cce74817 | 10776 | @c This is false ... |
c906108c SS |
10777 | Some @value{GDBN} features may be used in expressions regardless of the |
10778 | language you use: the @value{GDBN} @code{@@} and @code{::} operators, | |
10779 | and the @samp{@{type@}addr} construct (@pxref{Expressions, | |
10780 | ,Expressions}) can be used with the constructs of any supported | |
10781 | language. | |
10782 | ||
10783 | The following sections detail to what degree each source language is | |
10784 | supported by @value{GDBN}. These sections are not meant to be language | |
10785 | tutorials or references, but serve only as a reference guide to what the | |
10786 | @value{GDBN} expression parser accepts, and what input and output | |
10787 | formats should look like for different languages. There are many good | |
10788 | books written on each of these languages; please look to these for a | |
10789 | language reference or tutorial. | |
10790 | ||
c906108c | 10791 | @menu |
b37303ee | 10792 | * C:: C and C@t{++} |
b383017d | 10793 | * Objective-C:: Objective-C |
09d4efe1 | 10794 | * Fortran:: Fortran |
9c16f35a | 10795 | * Pascal:: Pascal |
b37303ee | 10796 | * Modula-2:: Modula-2 |
e07c999f | 10797 | * Ada:: Ada |
c906108c SS |
10798 | @end menu |
10799 | ||
6d2ebf8b | 10800 | @node C |
b37052ae | 10801 | @subsection C and C@t{++} |
7a292a7a | 10802 | |
b37052ae EZ |
10803 | @cindex C and C@t{++} |
10804 | @cindex expressions in C or C@t{++} | |
c906108c | 10805 | |
b37052ae | 10806 | Since C and C@t{++} are so closely related, many features of @value{GDBN} apply |
c906108c SS |
10807 | to both languages. Whenever this is the case, we discuss those languages |
10808 | together. | |
10809 | ||
41afff9a EZ |
10810 | @cindex C@t{++} |
10811 | @cindex @code{g++}, @sc{gnu} C@t{++} compiler | |
b37052ae EZ |
10812 | @cindex @sc{gnu} C@t{++} |
10813 | The C@t{++} debugging facilities are jointly implemented by the C@t{++} | |
10814 | compiler and @value{GDBN}. Therefore, to debug your C@t{++} code | |
10815 | effectively, you must compile your C@t{++} programs with a supported | |
10816 | C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++} | |
c906108c SS |
10817 | compiler (@code{aCC}). |
10818 | ||
0179ffac DC |
10819 | For best results when using @sc{gnu} C@t{++}, use the DWARF 2 debugging |
10820 | format; if it doesn't work on your system, try the stabs+ debugging | |
10821 | format. You can select those formats explicitly with the @code{g++} | |
10822 | command-line options @option{-gdwarf-2} and @option{-gstabs+}. | |
ce9341a1 BW |
10823 | @xref{Debugging Options,,Options for Debugging Your Program or GCC, |
10824 | gcc.info, Using the @sc{gnu} Compiler Collection (GCC)}. | |
c906108c | 10825 | |
c906108c | 10826 | @menu |
b37052ae EZ |
10827 | * C Operators:: C and C@t{++} operators |
10828 | * C Constants:: C and C@t{++} constants | |
79a6e687 | 10829 | * C Plus Plus Expressions:: C@t{++} expressions |
b37052ae EZ |
10830 | * C Defaults:: Default settings for C and C@t{++} |
10831 | * C Checks:: C and C@t{++} type and range checks | |
c906108c | 10832 | * Debugging C:: @value{GDBN} and C |
79a6e687 | 10833 | * Debugging C Plus Plus:: @value{GDBN} features for C@t{++} |
febe4383 | 10834 | * Decimal Floating Point:: Numbers in Decimal Floating Point format |
c906108c | 10835 | @end menu |
c906108c | 10836 | |
6d2ebf8b | 10837 | @node C Operators |
79a6e687 | 10838 | @subsubsection C and C@t{++} Operators |
7a292a7a | 10839 | |
b37052ae | 10840 | @cindex C and C@t{++} operators |
c906108c SS |
10841 | |
10842 | Operators must be defined on values of specific types. For instance, | |
10843 | @code{+} is defined on numbers, but not on structures. Operators are | |
5d161b24 | 10844 | often defined on groups of types. |
c906108c | 10845 | |
b37052ae | 10846 | For the purposes of C and C@t{++}, the following definitions hold: |
c906108c SS |
10847 | |
10848 | @itemize @bullet | |
53a5351d | 10849 | |
c906108c | 10850 | @item |
c906108c | 10851 | @emph{Integral types} include @code{int} with any of its storage-class |
b37052ae | 10852 | specifiers; @code{char}; @code{enum}; and, for C@t{++}, @code{bool}. |
c906108c SS |
10853 | |
10854 | @item | |
d4f3574e SS |
10855 | @emph{Floating-point types} include @code{float}, @code{double}, and |
10856 | @code{long double} (if supported by the target platform). | |
c906108c SS |
10857 | |
10858 | @item | |
53a5351d | 10859 | @emph{Pointer types} include all types defined as @code{(@var{type} *)}. |
c906108c SS |
10860 | |
10861 | @item | |
10862 | @emph{Scalar types} include all of the above. | |
53a5351d | 10863 | |
c906108c SS |
10864 | @end itemize |
10865 | ||
10866 | @noindent | |
10867 | The following operators are supported. They are listed here | |
10868 | in order of increasing precedence: | |
10869 | ||
10870 | @table @code | |
10871 | @item , | |
10872 | The comma or sequencing operator. Expressions in a comma-separated list | |
10873 | are evaluated from left to right, with the result of the entire | |
10874 | expression being the last expression evaluated. | |
10875 | ||
10876 | @item = | |
10877 | Assignment. The value of an assignment expression is the value | |
10878 | assigned. Defined on scalar types. | |
10879 | ||
10880 | @item @var{op}= | |
10881 | Used in an expression of the form @w{@code{@var{a} @var{op}= @var{b}}}, | |
10882 | and translated to @w{@code{@var{a} = @var{a op b}}}. | |
d4f3574e | 10883 | @w{@code{@var{op}=}} and @code{=} have the same precedence. |
c906108c SS |
10884 | @var{op} is any one of the operators @code{|}, @code{^}, @code{&}, |
10885 | @code{<<}, @code{>>}, @code{+}, @code{-}, @code{*}, @code{/}, @code{%}. | |
10886 | ||
10887 | @item ?: | |
10888 | The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought | |
10889 | of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an | |
10890 | integral type. | |
10891 | ||
10892 | @item || | |
10893 | Logical @sc{or}. Defined on integral types. | |
10894 | ||
10895 | @item && | |
10896 | Logical @sc{and}. Defined on integral types. | |
10897 | ||
10898 | @item | | |
10899 | Bitwise @sc{or}. Defined on integral types. | |
10900 | ||
10901 | @item ^ | |
10902 | Bitwise exclusive-@sc{or}. Defined on integral types. | |
10903 | ||
10904 | @item & | |
10905 | Bitwise @sc{and}. Defined on integral types. | |
10906 | ||
10907 | @item ==@r{, }!= | |
10908 | Equality and inequality. Defined on scalar types. The value of these | |
10909 | expressions is 0 for false and non-zero for true. | |
10910 | ||
10911 | @item <@r{, }>@r{, }<=@r{, }>= | |
10912 | Less than, greater than, less than or equal, greater than or equal. | |
10913 | Defined on scalar types. The value of these expressions is 0 for false | |
10914 | and non-zero for true. | |
10915 | ||
10916 | @item <<@r{, }>> | |
10917 | left shift, and right shift. Defined on integral types. | |
10918 | ||
10919 | @item @@ | |
10920 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
10921 | ||
10922 | @item +@r{, }- | |
10923 | Addition and subtraction. Defined on integral types, floating-point types and | |
10924 | pointer types. | |
10925 | ||
10926 | @item *@r{, }/@r{, }% | |
10927 | Multiplication, division, and modulus. Multiplication and division are | |
10928 | defined on integral and floating-point types. Modulus is defined on | |
10929 | integral types. | |
10930 | ||
10931 | @item ++@r{, }-- | |
10932 | Increment and decrement. When appearing before a variable, the | |
10933 | operation is performed before the variable is used in an expression; | |
10934 | when appearing after it, the variable's value is used before the | |
10935 | operation takes place. | |
10936 | ||
10937 | @item * | |
10938 | Pointer dereferencing. Defined on pointer types. Same precedence as | |
10939 | @code{++}. | |
10940 | ||
10941 | @item & | |
10942 | Address operator. Defined on variables. Same precedence as @code{++}. | |
10943 | ||
b37052ae EZ |
10944 | For debugging C@t{++}, @value{GDBN} implements a use of @samp{&} beyond what is |
10945 | allowed in the C@t{++} language itself: you can use @samp{&(&@var{ref})} | |
b17828ca | 10946 | to examine the address |
b37052ae | 10947 | where a C@t{++} reference variable (declared with @samp{&@var{ref}}) is |
c906108c | 10948 | stored. |
c906108c SS |
10949 | |
10950 | @item - | |
10951 | Negative. Defined on integral and floating-point types. Same | |
10952 | precedence as @code{++}. | |
10953 | ||
10954 | @item ! | |
10955 | Logical negation. Defined on integral types. Same precedence as | |
10956 | @code{++}. | |
10957 | ||
10958 | @item ~ | |
10959 | Bitwise complement operator. Defined on integral types. Same precedence as | |
10960 | @code{++}. | |
10961 | ||
10962 | ||
10963 | @item .@r{, }-> | |
10964 | Structure member, and pointer-to-structure member. For convenience, | |
10965 | @value{GDBN} regards the two as equivalent, choosing whether to dereference a | |
10966 | pointer based on the stored type information. | |
10967 | Defined on @code{struct} and @code{union} data. | |
10968 | ||
c906108c SS |
10969 | @item .*@r{, }->* |
10970 | Dereferences of pointers to members. | |
c906108c SS |
10971 | |
10972 | @item [] | |
10973 | Array indexing. @code{@var{a}[@var{i}]} is defined as | |
10974 | @code{*(@var{a}+@var{i})}. Same precedence as @code{->}. | |
10975 | ||
10976 | @item () | |
10977 | Function parameter list. Same precedence as @code{->}. | |
10978 | ||
c906108c | 10979 | @item :: |
b37052ae | 10980 | C@t{++} scope resolution operator. Defined on @code{struct}, @code{union}, |
7a292a7a | 10981 | and @code{class} types. |
c906108c SS |
10982 | |
10983 | @item :: | |
7a292a7a SS |
10984 | Doubled colons also represent the @value{GDBN} scope operator |
10985 | (@pxref{Expressions, ,Expressions}). Same precedence as @code{::}, | |
10986 | above. | |
c906108c SS |
10987 | @end table |
10988 | ||
c906108c SS |
10989 | If an operator is redefined in the user code, @value{GDBN} usually |
10990 | attempts to invoke the redefined version instead of using the operator's | |
10991 | predefined meaning. | |
c906108c | 10992 | |
6d2ebf8b | 10993 | @node C Constants |
79a6e687 | 10994 | @subsubsection C and C@t{++} Constants |
c906108c | 10995 | |
b37052ae | 10996 | @cindex C and C@t{++} constants |
c906108c | 10997 | |
b37052ae | 10998 | @value{GDBN} allows you to express the constants of C and C@t{++} in the |
c906108c | 10999 | following ways: |
c906108c SS |
11000 | |
11001 | @itemize @bullet | |
11002 | @item | |
11003 | Integer constants are a sequence of digits. Octal constants are | |
6ca652b0 EZ |
11004 | specified by a leading @samp{0} (i.e.@: zero), and hexadecimal constants |
11005 | by a leading @samp{0x} or @samp{0X}. Constants may also end with a letter | |
c906108c SS |
11006 | @samp{l}, specifying that the constant should be treated as a |
11007 | @code{long} value. | |
11008 | ||
11009 | @item | |
11010 | Floating point constants are a sequence of digits, followed by a decimal | |
11011 | point, followed by a sequence of digits, and optionally followed by an | |
11012 | exponent. An exponent is of the form: | |
11013 | @samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another | |
11014 | sequence of digits. The @samp{+} is optional for positive exponents. | |
d4f3574e SS |
11015 | A floating-point constant may also end with a letter @samp{f} or |
11016 | @samp{F}, specifying that the constant should be treated as being of | |
11017 | the @code{float} (as opposed to the default @code{double}) type; or with | |
11018 | a letter @samp{l} or @samp{L}, which specifies a @code{long double} | |
11019 | constant. | |
c906108c SS |
11020 | |
11021 | @item | |
11022 | Enumerated constants consist of enumerated identifiers, or their | |
11023 | integral equivalents. | |
11024 | ||
11025 | @item | |
11026 | Character constants are a single character surrounded by single quotes | |
11027 | (@code{'}), or a number---the ordinal value of the corresponding character | |
d4f3574e | 11028 | (usually its @sc{ascii} value). Within quotes, the single character may |
c906108c SS |
11029 | be represented by a letter or by @dfn{escape sequences}, which are of |
11030 | the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation | |
11031 | of the character's ordinal value; or of the form @samp{\@var{x}}, where | |
11032 | @samp{@var{x}} is a predefined special character---for example, | |
11033 | @samp{\n} for newline. | |
11034 | ||
11035 | @item | |
96a2c332 SS |
11036 | String constants are a sequence of character constants surrounded by |
11037 | double quotes (@code{"}). Any valid character constant (as described | |
11038 | above) may appear. Double quotes within the string must be preceded by | |
11039 | a backslash, so for instance @samp{"a\"b'c"} is a string of five | |
11040 | characters. | |
c906108c SS |
11041 | |
11042 | @item | |
11043 | Pointer constants are an integral value. You can also write pointers | |
11044 | to constants using the C operator @samp{&}. | |
11045 | ||
11046 | @item | |
11047 | Array constants are comma-separated lists surrounded by braces @samp{@{} | |
11048 | and @samp{@}}; for example, @samp{@{1,2,3@}} is a three-element array of | |
11049 | integers, @samp{@{@{1,2@}, @{3,4@}, @{5,6@}@}} is a three-by-two array, | |
11050 | and @samp{@{&"hi", &"there", &"fred"@}} is a three-element array of pointers. | |
11051 | @end itemize | |
11052 | ||
79a6e687 BW |
11053 | @node C Plus Plus Expressions |
11054 | @subsubsection C@t{++} Expressions | |
b37052ae EZ |
11055 | |
11056 | @cindex expressions in C@t{++} | |
11057 | @value{GDBN} expression handling can interpret most C@t{++} expressions. | |
11058 | ||
0179ffac DC |
11059 | @cindex debugging C@t{++} programs |
11060 | @cindex C@t{++} compilers | |
11061 | @cindex debug formats and C@t{++} | |
11062 | @cindex @value{NGCC} and C@t{++} | |
c906108c | 11063 | @quotation |
b37052ae | 11064 | @emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the |
0179ffac DC |
11065 | proper compiler and the proper debug format. Currently, @value{GDBN} |
11066 | works best when debugging C@t{++} code that is compiled with | |
11067 | @value{NGCC} 2.95.3 or with @value{NGCC} 3.1 or newer, using the options | |
11068 | @option{-gdwarf-2} or @option{-gstabs+}. DWARF 2 is preferred over | |
11069 | stabs+. Most configurations of @value{NGCC} emit either DWARF 2 or | |
11070 | stabs+ as their default debug format, so you usually don't need to | |
11071 | specify a debug format explicitly. Other compilers and/or debug formats | |
11072 | are likely to work badly or not at all when using @value{GDBN} to debug | |
11073 | C@t{++} code. | |
c906108c | 11074 | @end quotation |
c906108c SS |
11075 | |
11076 | @enumerate | |
11077 | ||
11078 | @cindex member functions | |
11079 | @item | |
11080 | Member function calls are allowed; you can use expressions like | |
11081 | ||
474c8240 | 11082 | @smallexample |
c906108c | 11083 | count = aml->GetOriginal(x, y) |
474c8240 | 11084 | @end smallexample |
c906108c | 11085 | |
41afff9a | 11086 | @vindex this@r{, inside C@t{++} member functions} |
b37052ae | 11087 | @cindex namespace in C@t{++} |
c906108c SS |
11088 | @item |
11089 | While a member function is active (in the selected stack frame), your | |
11090 | expressions have the same namespace available as the member function; | |
11091 | that is, @value{GDBN} allows implicit references to the class instance | |
b37052ae | 11092 | pointer @code{this} following the same rules as C@t{++}. |
c906108c | 11093 | |
c906108c | 11094 | @cindex call overloaded functions |
d4f3574e | 11095 | @cindex overloaded functions, calling |
b37052ae | 11096 | @cindex type conversions in C@t{++} |
c906108c SS |
11097 | @item |
11098 | You can call overloaded functions; @value{GDBN} resolves the function | |
d4f3574e | 11099 | call to the right definition, with some restrictions. @value{GDBN} does not |
c906108c SS |
11100 | perform overload resolution involving user-defined type conversions, |
11101 | calls to constructors, or instantiations of templates that do not exist | |
11102 | in the program. It also cannot handle ellipsis argument lists or | |
11103 | default arguments. | |
11104 | ||
11105 | It does perform integral conversions and promotions, floating-point | |
11106 | promotions, arithmetic conversions, pointer conversions, conversions of | |
11107 | class objects to base classes, and standard conversions such as those of | |
11108 | functions or arrays to pointers; it requires an exact match on the | |
11109 | number of function arguments. | |
11110 | ||
11111 | Overload resolution is always performed, unless you have specified | |
79a6e687 BW |
11112 | @code{set overload-resolution off}. @xref{Debugging C Plus Plus, |
11113 | ,@value{GDBN} Features for C@t{++}}. | |
c906108c | 11114 | |
d4f3574e | 11115 | You must specify @code{set overload-resolution off} in order to use an |
c906108c SS |
11116 | explicit function signature to call an overloaded function, as in |
11117 | @smallexample | |
11118 | p 'foo(char,int)'('x', 13) | |
11119 | @end smallexample | |
d4f3574e | 11120 | |
c906108c | 11121 | The @value{GDBN} command-completion facility can simplify this; |
79a6e687 | 11122 | see @ref{Completion, ,Command Completion}. |
c906108c | 11123 | |
c906108c SS |
11124 | @cindex reference declarations |
11125 | @item | |
b37052ae EZ |
11126 | @value{GDBN} understands variables declared as C@t{++} references; you can use |
11127 | them in expressions just as you do in C@t{++} source---they are automatically | |
c906108c SS |
11128 | dereferenced. |
11129 | ||
11130 | In the parameter list shown when @value{GDBN} displays a frame, the values of | |
11131 | reference variables are not displayed (unlike other variables); this | |
11132 | avoids clutter, since references are often used for large structures. | |
11133 | The @emph{address} of a reference variable is always shown, unless | |
11134 | you have specified @samp{set print address off}. | |
11135 | ||
11136 | @item | |
b37052ae | 11137 | @value{GDBN} supports the C@t{++} name resolution operator @code{::}---your |
c906108c SS |
11138 | expressions can use it just as expressions in your program do. Since |
11139 | one scope may be defined in another, you can use @code{::} repeatedly if | |
11140 | necessary, for example in an expression like | |
11141 | @samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows | |
b37052ae | 11142 | resolving name scope by reference to source files, in both C and C@t{++} |
79a6e687 | 11143 | debugging (@pxref{Variables, ,Program Variables}). |
c906108c SS |
11144 | @end enumerate |
11145 | ||
b37052ae | 11146 | In addition, when used with HP's C@t{++} compiler, @value{GDBN} supports |
53a5351d JM |
11147 | calling virtual functions correctly, printing out virtual bases of |
11148 | objects, calling functions in a base subobject, casting objects, and | |
11149 | invoking user-defined operators. | |
c906108c | 11150 | |
6d2ebf8b | 11151 | @node C Defaults |
79a6e687 | 11152 | @subsubsection C and C@t{++} Defaults |
7a292a7a | 11153 | |
b37052ae | 11154 | @cindex C and C@t{++} defaults |
c906108c | 11155 | |
c906108c SS |
11156 | If you allow @value{GDBN} to set type and range checking automatically, they |
11157 | both default to @code{off} whenever the working language changes to | |
b37052ae | 11158 | C or C@t{++}. This happens regardless of whether you or @value{GDBN} |
c906108c | 11159 | selects the working language. |
c906108c SS |
11160 | |
11161 | If you allow @value{GDBN} to set the language automatically, it | |
11162 | recognizes source files whose names end with @file{.c}, @file{.C}, or | |
11163 | @file{.cc}, etc, and when @value{GDBN} enters code compiled from one of | |
b37052ae | 11164 | these files, it sets the working language to C or C@t{++}. |
79a6e687 | 11165 | @xref{Automatically, ,Having @value{GDBN} Infer the Source Language}, |
c906108c SS |
11166 | for further details. |
11167 | ||
c906108c SS |
11168 | @c Type checking is (a) primarily motivated by Modula-2, and (b) |
11169 | @c unimplemented. If (b) changes, it might make sense to let this node | |
11170 | @c appear even if Mod-2 does not, but meanwhile ignore it. roland 16jul93. | |
7a292a7a | 11171 | |
6d2ebf8b | 11172 | @node C Checks |
79a6e687 | 11173 | @subsubsection C and C@t{++} Type and Range Checks |
7a292a7a | 11174 | |
b37052ae | 11175 | @cindex C and C@t{++} checks |
c906108c | 11176 | |
b37052ae | 11177 | By default, when @value{GDBN} parses C or C@t{++} expressions, type checking |
c906108c SS |
11178 | is not used. However, if you turn type checking on, @value{GDBN} |
11179 | considers two variables type equivalent if: | |
11180 | ||
11181 | @itemize @bullet | |
11182 | @item | |
11183 | The two variables are structured and have the same structure, union, or | |
11184 | enumerated tag. | |
11185 | ||
11186 | @item | |
11187 | The two variables have the same type name, or types that have been | |
11188 | declared equivalent through @code{typedef}. | |
11189 | ||
11190 | @ignore | |
11191 | @c leaving this out because neither J Gilmore nor R Pesch understand it. | |
11192 | @c FIXME--beers? | |
11193 | @item | |
11194 | The two @code{struct}, @code{union}, or @code{enum} variables are | |
11195 | declared in the same declaration. (Note: this may not be true for all C | |
11196 | compilers.) | |
11197 | @end ignore | |
11198 | @end itemize | |
11199 | ||
11200 | Range checking, if turned on, is done on mathematical operations. Array | |
11201 | indices are not checked, since they are often used to index a pointer | |
11202 | that is not itself an array. | |
c906108c | 11203 | |
6d2ebf8b | 11204 | @node Debugging C |
c906108c | 11205 | @subsubsection @value{GDBN} and C |
c906108c SS |
11206 | |
11207 | The @code{set print union} and @code{show print union} commands apply to | |
11208 | the @code{union} type. When set to @samp{on}, any @code{union} that is | |
7a292a7a SS |
11209 | inside a @code{struct} or @code{class} is also printed. Otherwise, it |
11210 | appears as @samp{@{...@}}. | |
c906108c SS |
11211 | |
11212 | The @code{@@} operator aids in the debugging of dynamic arrays, formed | |
11213 | with pointers and a memory allocation function. @xref{Expressions, | |
11214 | ,Expressions}. | |
11215 | ||
79a6e687 BW |
11216 | @node Debugging C Plus Plus |
11217 | @subsubsection @value{GDBN} Features for C@t{++} | |
c906108c | 11218 | |
b37052ae | 11219 | @cindex commands for C@t{++} |
7a292a7a | 11220 | |
b37052ae EZ |
11221 | Some @value{GDBN} commands are particularly useful with C@t{++}, and some are |
11222 | designed specifically for use with C@t{++}. Here is a summary: | |
c906108c SS |
11223 | |
11224 | @table @code | |
11225 | @cindex break in overloaded functions | |
11226 | @item @r{breakpoint menus} | |
11227 | When you want a breakpoint in a function whose name is overloaded, | |
6ba66d6a JB |
11228 | @value{GDBN} has the capability to display a menu of possible breakpoint |
11229 | locations to help you specify which function definition you want. | |
11230 | @xref{Ambiguous Expressions,,Ambiguous Expressions}. | |
c906108c | 11231 | |
b37052ae | 11232 | @cindex overloading in C@t{++} |
c906108c SS |
11233 | @item rbreak @var{regex} |
11234 | Setting breakpoints using regular expressions is helpful for setting | |
11235 | breakpoints on overloaded functions that are not members of any special | |
11236 | classes. | |
79a6e687 | 11237 | @xref{Set Breaks, ,Setting Breakpoints}. |
c906108c | 11238 | |
b37052ae | 11239 | @cindex C@t{++} exception handling |
c906108c SS |
11240 | @item catch throw |
11241 | @itemx catch catch | |
b37052ae | 11242 | Debug C@t{++} exception handling using these commands. @xref{Set |
79a6e687 | 11243 | Catchpoints, , Setting Catchpoints}. |
c906108c SS |
11244 | |
11245 | @cindex inheritance | |
11246 | @item ptype @var{typename} | |
11247 | Print inheritance relationships as well as other information for type | |
11248 | @var{typename}. | |
11249 | @xref{Symbols, ,Examining the Symbol Table}. | |
11250 | ||
b37052ae | 11251 | @cindex C@t{++} symbol display |
c906108c SS |
11252 | @item set print demangle |
11253 | @itemx show print demangle | |
11254 | @itemx set print asm-demangle | |
11255 | @itemx show print asm-demangle | |
b37052ae EZ |
11256 | Control whether C@t{++} symbols display in their source form, both when |
11257 | displaying code as C@t{++} source and when displaying disassemblies. | |
79a6e687 | 11258 | @xref{Print Settings, ,Print Settings}. |
c906108c SS |
11259 | |
11260 | @item set print object | |
11261 | @itemx show print object | |
11262 | Choose whether to print derived (actual) or declared types of objects. | |
79a6e687 | 11263 | @xref{Print Settings, ,Print Settings}. |
c906108c SS |
11264 | |
11265 | @item set print vtbl | |
11266 | @itemx show print vtbl | |
11267 | Control the format for printing virtual function tables. | |
79a6e687 | 11268 | @xref{Print Settings, ,Print Settings}. |
c906108c | 11269 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 11270 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
11271 | |
11272 | @kindex set overload-resolution | |
d4f3574e | 11273 | @cindex overloaded functions, overload resolution |
c906108c | 11274 | @item set overload-resolution on |
b37052ae | 11275 | Enable overload resolution for C@t{++} expression evaluation. The default |
c906108c SS |
11276 | is on. For overloaded functions, @value{GDBN} evaluates the arguments |
11277 | and searches for a function whose signature matches the argument types, | |
79a6e687 BW |
11278 | using the standard C@t{++} conversion rules (see @ref{C Plus Plus |
11279 | Expressions, ,C@t{++} Expressions}, for details). | |
11280 | If it cannot find a match, it emits a message. | |
c906108c SS |
11281 | |
11282 | @item set overload-resolution off | |
b37052ae | 11283 | Disable overload resolution for C@t{++} expression evaluation. For |
c906108c SS |
11284 | overloaded functions that are not class member functions, @value{GDBN} |
11285 | chooses the first function of the specified name that it finds in the | |
11286 | symbol table, whether or not its arguments are of the correct type. For | |
11287 | overloaded functions that are class member functions, @value{GDBN} | |
11288 | searches for a function whose signature @emph{exactly} matches the | |
11289 | argument types. | |
c906108c | 11290 | |
9c16f35a EZ |
11291 | @kindex show overload-resolution |
11292 | @item show overload-resolution | |
11293 | Show the current setting of overload resolution. | |
11294 | ||
c906108c SS |
11295 | @item @r{Overloaded symbol names} |
11296 | You can specify a particular definition of an overloaded symbol, using | |
b37052ae | 11297 | the same notation that is used to declare such symbols in C@t{++}: type |
c906108c SS |
11298 | @code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can |
11299 | also use the @value{GDBN} command-line word completion facilities to list the | |
11300 | available choices, or to finish the type list for you. | |
79a6e687 | 11301 | @xref{Completion,, Command Completion}, for details on how to do this. |
c906108c | 11302 | @end table |
c906108c | 11303 | |
febe4383 TJB |
11304 | @node Decimal Floating Point |
11305 | @subsubsection Decimal Floating Point format | |
11306 | @cindex decimal floating point format | |
11307 | ||
11308 | @value{GDBN} can examine, set and perform computations with numbers in | |
11309 | decimal floating point format, which in the C language correspond to the | |
11310 | @code{_Decimal32}, @code{_Decimal64} and @code{_Decimal128} types as | |
11311 | specified by the extension to support decimal floating-point arithmetic. | |
11312 | ||
11313 | There are two encodings in use, depending on the architecture: BID (Binary | |
11314 | Integer Decimal) for x86 and x86-64, and DPD (Densely Packed Decimal) for | |
99e008fe | 11315 | PowerPC. @value{GDBN} will use the appropriate encoding for the configured |
febe4383 TJB |
11316 | target. |
11317 | ||
11318 | Because of a limitation in @file{libdecnumber}, the library used by @value{GDBN} | |
11319 | to manipulate decimal floating point numbers, it is not possible to convert | |
11320 | (using a cast, for example) integers wider than 32-bit to decimal float. | |
11321 | ||
11322 | In addition, in order to imitate @value{GDBN}'s behaviour with binary floating | |
11323 | point computations, error checking in decimal float operations ignores | |
11324 | underflow, overflow and divide by zero exceptions. | |
11325 | ||
4acd40f3 | 11326 | In the PowerPC architecture, @value{GDBN} provides a set of pseudo-registers |
99e008fe EZ |
11327 | to inspect @code{_Decimal128} values stored in floating point registers. |
11328 | See @ref{PowerPC,,PowerPC} for more details. | |
4acd40f3 | 11329 | |
b37303ee AF |
11330 | @node Objective-C |
11331 | @subsection Objective-C | |
11332 | ||
11333 | @cindex Objective-C | |
11334 | This section provides information about some commands and command | |
721c2651 EZ |
11335 | options that are useful for debugging Objective-C code. See also |
11336 | @ref{Symbols, info classes}, and @ref{Symbols, info selectors}, for a | |
11337 | few more commands specific to Objective-C support. | |
b37303ee AF |
11338 | |
11339 | @menu | |
b383017d RM |
11340 | * Method Names in Commands:: |
11341 | * The Print Command with Objective-C:: | |
b37303ee AF |
11342 | @end menu |
11343 | ||
c8f4133a | 11344 | @node Method Names in Commands |
b37303ee AF |
11345 | @subsubsection Method Names in Commands |
11346 | ||
11347 | The following commands have been extended to accept Objective-C method | |
11348 | names as line specifications: | |
11349 | ||
11350 | @kindex clear@r{, and Objective-C} | |
11351 | @kindex break@r{, and Objective-C} | |
11352 | @kindex info line@r{, and Objective-C} | |
11353 | @kindex jump@r{, and Objective-C} | |
11354 | @kindex list@r{, and Objective-C} | |
11355 | @itemize | |
11356 | @item @code{clear} | |
11357 | @item @code{break} | |
11358 | @item @code{info line} | |
11359 | @item @code{jump} | |
11360 | @item @code{list} | |
11361 | @end itemize | |
11362 | ||
11363 | A fully qualified Objective-C method name is specified as | |
11364 | ||
11365 | @smallexample | |
11366 | -[@var{Class} @var{methodName}] | |
11367 | @end smallexample | |
11368 | ||
c552b3bb JM |
11369 | where the minus sign is used to indicate an instance method and a |
11370 | plus sign (not shown) is used to indicate a class method. The class | |
11371 | name @var{Class} and method name @var{methodName} are enclosed in | |
11372 | brackets, similar to the way messages are specified in Objective-C | |
11373 | source code. For example, to set a breakpoint at the @code{create} | |
11374 | instance method of class @code{Fruit} in the program currently being | |
11375 | debugged, enter: | |
b37303ee AF |
11376 | |
11377 | @smallexample | |
11378 | break -[Fruit create] | |
11379 | @end smallexample | |
11380 | ||
11381 | To list ten program lines around the @code{initialize} class method, | |
11382 | enter: | |
11383 | ||
11384 | @smallexample | |
11385 | list +[NSText initialize] | |
11386 | @end smallexample | |
11387 | ||
c552b3bb JM |
11388 | In the current version of @value{GDBN}, the plus or minus sign is |
11389 | required. In future versions of @value{GDBN}, the plus or minus | |
11390 | sign will be optional, but you can use it to narrow the search. It | |
11391 | is also possible to specify just a method name: | |
b37303ee AF |
11392 | |
11393 | @smallexample | |
11394 | break create | |
11395 | @end smallexample | |
11396 | ||
11397 | You must specify the complete method name, including any colons. If | |
11398 | your program's source files contain more than one @code{create} method, | |
11399 | you'll be presented with a numbered list of classes that implement that | |
11400 | method. Indicate your choice by number, or type @samp{0} to exit if | |
11401 | none apply. | |
11402 | ||
11403 | As another example, to clear a breakpoint established at the | |
11404 | @code{makeKeyAndOrderFront:} method of the @code{NSWindow} class, enter: | |
11405 | ||
11406 | @smallexample | |
11407 | clear -[NSWindow makeKeyAndOrderFront:] | |
11408 | @end smallexample | |
11409 | ||
11410 | @node The Print Command with Objective-C | |
11411 | @subsubsection The Print Command With Objective-C | |
721c2651 | 11412 | @cindex Objective-C, print objects |
c552b3bb JM |
11413 | @kindex print-object |
11414 | @kindex po @r{(@code{print-object})} | |
b37303ee | 11415 | |
c552b3bb | 11416 | The print command has also been extended to accept methods. For example: |
b37303ee AF |
11417 | |
11418 | @smallexample | |
c552b3bb | 11419 | print -[@var{object} hash] |
b37303ee AF |
11420 | @end smallexample |
11421 | ||
11422 | @cindex print an Objective-C object description | |
c552b3bb JM |
11423 | @cindex @code{_NSPrintForDebugger}, and printing Objective-C objects |
11424 | @noindent | |
11425 | will tell @value{GDBN} to send the @code{hash} message to @var{object} | |
11426 | and print the result. Also, an additional command has been added, | |
11427 | @code{print-object} or @code{po} for short, which is meant to print | |
11428 | the description of an object. However, this command may only work | |
11429 | with certain Objective-C libraries that have a particular hook | |
11430 | function, @code{_NSPrintForDebugger}, defined. | |
b37303ee | 11431 | |
09d4efe1 EZ |
11432 | @node Fortran |
11433 | @subsection Fortran | |
11434 | @cindex Fortran-specific support in @value{GDBN} | |
11435 | ||
814e32d7 WZ |
11436 | @value{GDBN} can be used to debug programs written in Fortran, but it |
11437 | currently supports only the features of Fortran 77 language. | |
11438 | ||
11439 | @cindex trailing underscore, in Fortran symbols | |
11440 | Some Fortran compilers (@sc{gnu} Fortran 77 and Fortran 95 compilers | |
11441 | among them) append an underscore to the names of variables and | |
11442 | functions. When you debug programs compiled by those compilers, you | |
11443 | will need to refer to variables and functions with a trailing | |
11444 | underscore. | |
11445 | ||
11446 | @menu | |
11447 | * Fortran Operators:: Fortran operators and expressions | |
11448 | * Fortran Defaults:: Default settings for Fortran | |
79a6e687 | 11449 | * Special Fortran Commands:: Special @value{GDBN} commands for Fortran |
814e32d7 WZ |
11450 | @end menu |
11451 | ||
11452 | @node Fortran Operators | |
79a6e687 | 11453 | @subsubsection Fortran Operators and Expressions |
814e32d7 WZ |
11454 | |
11455 | @cindex Fortran operators and expressions | |
11456 | ||
11457 | Operators must be defined on values of specific types. For instance, | |
11458 | @code{+} is defined on numbers, but not on characters or other non- | |
ff2587ec | 11459 | arithmetic types. Operators are often defined on groups of types. |
814e32d7 WZ |
11460 | |
11461 | @table @code | |
11462 | @item ** | |
99e008fe | 11463 | The exponentiation operator. It raises the first operand to the power |
814e32d7 WZ |
11464 | of the second one. |
11465 | ||
11466 | @item : | |
11467 | The range operator. Normally used in the form of array(low:high) to | |
11468 | represent a section of array. | |
68837c9d MD |
11469 | |
11470 | @item % | |
11471 | The access component operator. Normally used to access elements in derived | |
11472 | types. Also suitable for unions. As unions aren't part of regular Fortran, | |
11473 | this can only happen when accessing a register that uses a gdbarch-defined | |
11474 | union type. | |
814e32d7 WZ |
11475 | @end table |
11476 | ||
11477 | @node Fortran Defaults | |
11478 | @subsubsection Fortran Defaults | |
11479 | ||
11480 | @cindex Fortran Defaults | |
11481 | ||
11482 | Fortran symbols are usually case-insensitive, so @value{GDBN} by | |
11483 | default uses case-insensitive matches for Fortran symbols. You can | |
11484 | change that with the @samp{set case-insensitive} command, see | |
11485 | @ref{Symbols}, for the details. | |
11486 | ||
79a6e687 BW |
11487 | @node Special Fortran Commands |
11488 | @subsubsection Special Fortran Commands | |
814e32d7 WZ |
11489 | |
11490 | @cindex Special Fortran commands | |
11491 | ||
db2e3e2e BW |
11492 | @value{GDBN} has some commands to support Fortran-specific features, |
11493 | such as displaying common blocks. | |
814e32d7 | 11494 | |
09d4efe1 EZ |
11495 | @table @code |
11496 | @cindex @code{COMMON} blocks, Fortran | |
11497 | @kindex info common | |
11498 | @item info common @r{[}@var{common-name}@r{]} | |
11499 | This command prints the values contained in the Fortran @code{COMMON} | |
11500 | block whose name is @var{common-name}. With no argument, the names of | |
d52fb0e9 | 11501 | all @code{COMMON} blocks visible at the current program location are |
09d4efe1 EZ |
11502 | printed. |
11503 | @end table | |
11504 | ||
9c16f35a EZ |
11505 | @node Pascal |
11506 | @subsection Pascal | |
11507 | ||
11508 | @cindex Pascal support in @value{GDBN}, limitations | |
11509 | Debugging Pascal programs which use sets, subranges, file variables, or | |
11510 | nested functions does not currently work. @value{GDBN} does not support | |
11511 | entering expressions, printing values, or similar features using Pascal | |
11512 | syntax. | |
11513 | ||
11514 | The Pascal-specific command @code{set print pascal_static-members} | |
11515 | controls whether static members of Pascal objects are displayed. | |
11516 | @xref{Print Settings, pascal_static-members}. | |
11517 | ||
09d4efe1 | 11518 | @node Modula-2 |
c906108c | 11519 | @subsection Modula-2 |
7a292a7a | 11520 | |
d4f3574e | 11521 | @cindex Modula-2, @value{GDBN} support |
c906108c SS |
11522 | |
11523 | The extensions made to @value{GDBN} to support Modula-2 only support | |
11524 | output from the @sc{gnu} Modula-2 compiler (which is currently being | |
11525 | developed). Other Modula-2 compilers are not currently supported, and | |
11526 | attempting to debug executables produced by them is most likely | |
11527 | to give an error as @value{GDBN} reads in the executable's symbol | |
11528 | table. | |
11529 | ||
11530 | @cindex expressions in Modula-2 | |
11531 | @menu | |
11532 | * M2 Operators:: Built-in operators | |
11533 | * Built-In Func/Proc:: Built-in functions and procedures | |
11534 | * M2 Constants:: Modula-2 constants | |
72019c9c | 11535 | * M2 Types:: Modula-2 types |
c906108c SS |
11536 | * M2 Defaults:: Default settings for Modula-2 |
11537 | * Deviations:: Deviations from standard Modula-2 | |
11538 | * M2 Checks:: Modula-2 type and range checks | |
11539 | * M2 Scope:: The scope operators @code{::} and @code{.} | |
11540 | * GDB/M2:: @value{GDBN} and Modula-2 | |
11541 | @end menu | |
11542 | ||
6d2ebf8b | 11543 | @node M2 Operators |
c906108c SS |
11544 | @subsubsection Operators |
11545 | @cindex Modula-2 operators | |
11546 | ||
11547 | Operators must be defined on values of specific types. For instance, | |
11548 | @code{+} is defined on numbers, but not on structures. Operators are | |
11549 | often defined on groups of types. For the purposes of Modula-2, the | |
11550 | following definitions hold: | |
11551 | ||
11552 | @itemize @bullet | |
11553 | ||
11554 | @item | |
11555 | @emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and | |
11556 | their subranges. | |
11557 | ||
11558 | @item | |
11559 | @emph{Character types} consist of @code{CHAR} and its subranges. | |
11560 | ||
11561 | @item | |
11562 | @emph{Floating-point types} consist of @code{REAL}. | |
11563 | ||
11564 | @item | |
11565 | @emph{Pointer types} consist of anything declared as @code{POINTER TO | |
11566 | @var{type}}. | |
11567 | ||
11568 | @item | |
11569 | @emph{Scalar types} consist of all of the above. | |
11570 | ||
11571 | @item | |
11572 | @emph{Set types} consist of @code{SET} and @code{BITSET} types. | |
11573 | ||
11574 | @item | |
11575 | @emph{Boolean types} consist of @code{BOOLEAN}. | |
11576 | @end itemize | |
11577 | ||
11578 | @noindent | |
11579 | The following operators are supported, and appear in order of | |
11580 | increasing precedence: | |
11581 | ||
11582 | @table @code | |
11583 | @item , | |
11584 | Function argument or array index separator. | |
11585 | ||
11586 | @item := | |
11587 | Assignment. The value of @var{var} @code{:=} @var{value} is | |
11588 | @var{value}. | |
11589 | ||
11590 | @item <@r{, }> | |
11591 | Less than, greater than on integral, floating-point, or enumerated | |
11592 | types. | |
11593 | ||
11594 | @item <=@r{, }>= | |
96a2c332 | 11595 | Less than or equal to, greater than or equal to |
c906108c SS |
11596 | on integral, floating-point and enumerated types, or set inclusion on |
11597 | set types. Same precedence as @code{<}. | |
11598 | ||
11599 | @item =@r{, }<>@r{, }# | |
11600 | Equality and two ways of expressing inequality, valid on scalar types. | |
11601 | Same precedence as @code{<}. In @value{GDBN} scripts, only @code{<>} is | |
11602 | available for inequality, since @code{#} conflicts with the script | |
11603 | comment character. | |
11604 | ||
11605 | @item IN | |
11606 | Set membership. Defined on set types and the types of their members. | |
11607 | Same precedence as @code{<}. | |
11608 | ||
11609 | @item OR | |
11610 | Boolean disjunction. Defined on boolean types. | |
11611 | ||
11612 | @item AND@r{, }& | |
d4f3574e | 11613 | Boolean conjunction. Defined on boolean types. |
c906108c SS |
11614 | |
11615 | @item @@ | |
11616 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
11617 | ||
11618 | @item +@r{, }- | |
11619 | Addition and subtraction on integral and floating-point types, or union | |
11620 | and difference on set types. | |
11621 | ||
11622 | @item * | |
11623 | Multiplication on integral and floating-point types, or set intersection | |
11624 | on set types. | |
11625 | ||
11626 | @item / | |
11627 | Division on floating-point types, or symmetric set difference on set | |
11628 | types. Same precedence as @code{*}. | |
11629 | ||
11630 | @item DIV@r{, }MOD | |
11631 | Integer division and remainder. Defined on integral types. Same | |
11632 | precedence as @code{*}. | |
11633 | ||
11634 | @item - | |
99e008fe | 11635 | Negative. Defined on @code{INTEGER} and @code{REAL} data. |
c906108c SS |
11636 | |
11637 | @item ^ | |
11638 | Pointer dereferencing. Defined on pointer types. | |
11639 | ||
11640 | @item NOT | |
11641 | Boolean negation. Defined on boolean types. Same precedence as | |
11642 | @code{^}. | |
11643 | ||
11644 | @item . | |
11645 | @code{RECORD} field selector. Defined on @code{RECORD} data. Same | |
11646 | precedence as @code{^}. | |
11647 | ||
11648 | @item [] | |
11649 | Array indexing. Defined on @code{ARRAY} data. Same precedence as @code{^}. | |
11650 | ||
11651 | @item () | |
11652 | Procedure argument list. Defined on @code{PROCEDURE} objects. Same precedence | |
11653 | as @code{^}. | |
11654 | ||
11655 | @item ::@r{, }. | |
11656 | @value{GDBN} and Modula-2 scope operators. | |
11657 | @end table | |
11658 | ||
11659 | @quotation | |
72019c9c | 11660 | @emph{Warning:} Set expressions and their operations are not yet supported, so @value{GDBN} |
c906108c SS |
11661 | treats the use of the operator @code{IN}, or the use of operators |
11662 | @code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#}, | |
11663 | @code{<=}, and @code{>=} on sets as an error. | |
11664 | @end quotation | |
11665 | ||
cb51c4e0 | 11666 | |
6d2ebf8b | 11667 | @node Built-In Func/Proc |
79a6e687 | 11668 | @subsubsection Built-in Functions and Procedures |
cb51c4e0 | 11669 | @cindex Modula-2 built-ins |
c906108c SS |
11670 | |
11671 | Modula-2 also makes available several built-in procedures and functions. | |
11672 | In describing these, the following metavariables are used: | |
11673 | ||
11674 | @table @var | |
11675 | ||
11676 | @item a | |
11677 | represents an @code{ARRAY} variable. | |
11678 | ||
11679 | @item c | |
11680 | represents a @code{CHAR} constant or variable. | |
11681 | ||
11682 | @item i | |
11683 | represents a variable or constant of integral type. | |
11684 | ||
11685 | @item m | |
11686 | represents an identifier that belongs to a set. Generally used in the | |
11687 | same function with the metavariable @var{s}. The type of @var{s} should | |
11688 | be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}). | |
11689 | ||
11690 | @item n | |
11691 | represents a variable or constant of integral or floating-point type. | |
11692 | ||
11693 | @item r | |
11694 | represents a variable or constant of floating-point type. | |
11695 | ||
11696 | @item t | |
11697 | represents a type. | |
11698 | ||
11699 | @item v | |
11700 | represents a variable. | |
11701 | ||
11702 | @item x | |
11703 | represents a variable or constant of one of many types. See the | |
11704 | explanation of the function for details. | |
11705 | @end table | |
11706 | ||
11707 | All Modula-2 built-in procedures also return a result, described below. | |
11708 | ||
11709 | @table @code | |
11710 | @item ABS(@var{n}) | |
11711 | Returns the absolute value of @var{n}. | |
11712 | ||
11713 | @item CAP(@var{c}) | |
11714 | If @var{c} is a lower case letter, it returns its upper case | |
c3f6f71d | 11715 | equivalent, otherwise it returns its argument. |
c906108c SS |
11716 | |
11717 | @item CHR(@var{i}) | |
11718 | Returns the character whose ordinal value is @var{i}. | |
11719 | ||
11720 | @item DEC(@var{v}) | |
c3f6f71d | 11721 | Decrements the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
11722 | |
11723 | @item DEC(@var{v},@var{i}) | |
11724 | Decrements the value in the variable @var{v} by @var{i}. Returns the | |
11725 | new value. | |
11726 | ||
11727 | @item EXCL(@var{m},@var{s}) | |
11728 | Removes the element @var{m} from the set @var{s}. Returns the new | |
11729 | set. | |
11730 | ||
11731 | @item FLOAT(@var{i}) | |
11732 | Returns the floating point equivalent of the integer @var{i}. | |
11733 | ||
11734 | @item HIGH(@var{a}) | |
11735 | Returns the index of the last member of @var{a}. | |
11736 | ||
11737 | @item INC(@var{v}) | |
c3f6f71d | 11738 | Increments the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
11739 | |
11740 | @item INC(@var{v},@var{i}) | |
11741 | Increments the value in the variable @var{v} by @var{i}. Returns the | |
11742 | new value. | |
11743 | ||
11744 | @item INCL(@var{m},@var{s}) | |
11745 | Adds the element @var{m} to the set @var{s} if it is not already | |
11746 | there. Returns the new set. | |
11747 | ||
11748 | @item MAX(@var{t}) | |
11749 | Returns the maximum value of the type @var{t}. | |
11750 | ||
11751 | @item MIN(@var{t}) | |
11752 | Returns the minimum value of the type @var{t}. | |
11753 | ||
11754 | @item ODD(@var{i}) | |
11755 | Returns boolean TRUE if @var{i} is an odd number. | |
11756 | ||
11757 | @item ORD(@var{x}) | |
11758 | Returns the ordinal value of its argument. For example, the ordinal | |
c3f6f71d JM |
11759 | value of a character is its @sc{ascii} value (on machines supporting the |
11760 | @sc{ascii} character set). @var{x} must be of an ordered type, which include | |
c906108c SS |
11761 | integral, character and enumerated types. |
11762 | ||
11763 | @item SIZE(@var{x}) | |
11764 | Returns the size of its argument. @var{x} can be a variable or a type. | |
11765 | ||
11766 | @item TRUNC(@var{r}) | |
11767 | Returns the integral part of @var{r}. | |
11768 | ||
844781a1 GM |
11769 | @item TSIZE(@var{x}) |
11770 | Returns the size of its argument. @var{x} can be a variable or a type. | |
11771 | ||
c906108c SS |
11772 | @item VAL(@var{t},@var{i}) |
11773 | Returns the member of the type @var{t} whose ordinal value is @var{i}. | |
11774 | @end table | |
11775 | ||
11776 | @quotation | |
11777 | @emph{Warning:} Sets and their operations are not yet supported, so | |
11778 | @value{GDBN} treats the use of procedures @code{INCL} and @code{EXCL} as | |
11779 | an error. | |
11780 | @end quotation | |
11781 | ||
11782 | @cindex Modula-2 constants | |
6d2ebf8b | 11783 | @node M2 Constants |
c906108c SS |
11784 | @subsubsection Constants |
11785 | ||
11786 | @value{GDBN} allows you to express the constants of Modula-2 in the following | |
11787 | ways: | |
11788 | ||
11789 | @itemize @bullet | |
11790 | ||
11791 | @item | |
11792 | Integer constants are simply a sequence of digits. When used in an | |
11793 | expression, a constant is interpreted to be type-compatible with the | |
11794 | rest of the expression. Hexadecimal integers are specified by a | |
11795 | trailing @samp{H}, and octal integers by a trailing @samp{B}. | |
11796 | ||
11797 | @item | |
11798 | Floating point constants appear as a sequence of digits, followed by a | |
11799 | decimal point and another sequence of digits. An optional exponent can | |
11800 | then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where | |
11801 | @samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the | |
11802 | digits of the floating point constant must be valid decimal (base 10) | |
11803 | digits. | |
11804 | ||
11805 | @item | |
11806 | Character constants consist of a single character enclosed by a pair of | |
11807 | like quotes, either single (@code{'}) or double (@code{"}). They may | |
c3f6f71d | 11808 | also be expressed by their ordinal value (their @sc{ascii} value, usually) |
c906108c SS |
11809 | followed by a @samp{C}. |
11810 | ||
11811 | @item | |
11812 | String constants consist of a sequence of characters enclosed by a | |
11813 | pair of like quotes, either single (@code{'}) or double (@code{"}). | |
11814 | Escape sequences in the style of C are also allowed. @xref{C | |
79a6e687 | 11815 | Constants, ,C and C@t{++} Constants}, for a brief explanation of escape |
c906108c SS |
11816 | sequences. |
11817 | ||
11818 | @item | |
11819 | Enumerated constants consist of an enumerated identifier. | |
11820 | ||
11821 | @item | |
11822 | Boolean constants consist of the identifiers @code{TRUE} and | |
11823 | @code{FALSE}. | |
11824 | ||
11825 | @item | |
11826 | Pointer constants consist of integral values only. | |
11827 | ||
11828 | @item | |
11829 | Set constants are not yet supported. | |
11830 | @end itemize | |
11831 | ||
72019c9c GM |
11832 | @node M2 Types |
11833 | @subsubsection Modula-2 Types | |
11834 | @cindex Modula-2 types | |
11835 | ||
11836 | Currently @value{GDBN} can print the following data types in Modula-2 | |
11837 | syntax: array types, record types, set types, pointer types, procedure | |
11838 | types, enumerated types, subrange types and base types. You can also | |
11839 | print the contents of variables declared using these type. | |
11840 | This section gives a number of simple source code examples together with | |
11841 | sample @value{GDBN} sessions. | |
11842 | ||
11843 | The first example contains the following section of code: | |
11844 | ||
11845 | @smallexample | |
11846 | VAR | |
11847 | s: SET OF CHAR ; | |
11848 | r: [20..40] ; | |
11849 | @end smallexample | |
11850 | ||
11851 | @noindent | |
11852 | and you can request @value{GDBN} to interrogate the type and value of | |
11853 | @code{r} and @code{s}. | |
11854 | ||
11855 | @smallexample | |
11856 | (@value{GDBP}) print s | |
11857 | @{'A'..'C', 'Z'@} | |
11858 | (@value{GDBP}) ptype s | |
11859 | SET OF CHAR | |
11860 | (@value{GDBP}) print r | |
11861 | 21 | |
11862 | (@value{GDBP}) ptype r | |
11863 | [20..40] | |
11864 | @end smallexample | |
11865 | ||
11866 | @noindent | |
11867 | Likewise if your source code declares @code{s} as: | |
11868 | ||
11869 | @smallexample | |
11870 | VAR | |
11871 | s: SET ['A'..'Z'] ; | |
11872 | @end smallexample | |
11873 | ||
11874 | @noindent | |
11875 | then you may query the type of @code{s} by: | |
11876 | ||
11877 | @smallexample | |
11878 | (@value{GDBP}) ptype s | |
11879 | type = SET ['A'..'Z'] | |
11880 | @end smallexample | |
11881 | ||
11882 | @noindent | |
11883 | Note that at present you cannot interactively manipulate set | |
11884 | expressions using the debugger. | |
11885 | ||
11886 | The following example shows how you might declare an array in Modula-2 | |
11887 | and how you can interact with @value{GDBN} to print its type and contents: | |
11888 | ||
11889 | @smallexample | |
11890 | VAR | |
11891 | s: ARRAY [-10..10] OF CHAR ; | |
11892 | @end smallexample | |
11893 | ||
11894 | @smallexample | |
11895 | (@value{GDBP}) ptype s | |
11896 | ARRAY [-10..10] OF CHAR | |
11897 | @end smallexample | |
11898 | ||
11899 | Note that the array handling is not yet complete and although the type | |
11900 | is printed correctly, expression handling still assumes that all | |
11901 | arrays have a lower bound of zero and not @code{-10} as in the example | |
844781a1 | 11902 | above. |
72019c9c GM |
11903 | |
11904 | Here are some more type related Modula-2 examples: | |
11905 | ||
11906 | @smallexample | |
11907 | TYPE | |
11908 | colour = (blue, red, yellow, green) ; | |
11909 | t = [blue..yellow] ; | |
11910 | VAR | |
11911 | s: t ; | |
11912 | BEGIN | |
11913 | s := blue ; | |
11914 | @end smallexample | |
11915 | ||
11916 | @noindent | |
11917 | The @value{GDBN} interaction shows how you can query the data type | |
11918 | and value of a variable. | |
11919 | ||
11920 | @smallexample | |
11921 | (@value{GDBP}) print s | |
11922 | $1 = blue | |
11923 | (@value{GDBP}) ptype t | |
11924 | type = [blue..yellow] | |
11925 | @end smallexample | |
11926 | ||
11927 | @noindent | |
11928 | In this example a Modula-2 array is declared and its contents | |
11929 | displayed. Observe that the contents are written in the same way as | |
11930 | their @code{C} counterparts. | |
11931 | ||
11932 | @smallexample | |
11933 | VAR | |
11934 | s: ARRAY [1..5] OF CARDINAL ; | |
11935 | BEGIN | |
11936 | s[1] := 1 ; | |
11937 | @end smallexample | |
11938 | ||
11939 | @smallexample | |
11940 | (@value{GDBP}) print s | |
11941 | $1 = @{1, 0, 0, 0, 0@} | |
11942 | (@value{GDBP}) ptype s | |
11943 | type = ARRAY [1..5] OF CARDINAL | |
11944 | @end smallexample | |
11945 | ||
11946 | The Modula-2 language interface to @value{GDBN} also understands | |
11947 | pointer types as shown in this example: | |
11948 | ||
11949 | @smallexample | |
11950 | VAR | |
11951 | s: POINTER TO ARRAY [1..5] OF CARDINAL ; | |
11952 | BEGIN | |
11953 | NEW(s) ; | |
11954 | s^[1] := 1 ; | |
11955 | @end smallexample | |
11956 | ||
11957 | @noindent | |
11958 | and you can request that @value{GDBN} describes the type of @code{s}. | |
11959 | ||
11960 | @smallexample | |
11961 | (@value{GDBP}) ptype s | |
11962 | type = POINTER TO ARRAY [1..5] OF CARDINAL | |
11963 | @end smallexample | |
11964 | ||
11965 | @value{GDBN} handles compound types as we can see in this example. | |
11966 | Here we combine array types, record types, pointer types and subrange | |
11967 | types: | |
11968 | ||
11969 | @smallexample | |
11970 | TYPE | |
11971 | foo = RECORD | |
11972 | f1: CARDINAL ; | |
11973 | f2: CHAR ; | |
11974 | f3: myarray ; | |
11975 | END ; | |
11976 | ||
11977 | myarray = ARRAY myrange OF CARDINAL ; | |
11978 | myrange = [-2..2] ; | |
11979 | VAR | |
11980 | s: POINTER TO ARRAY myrange OF foo ; | |
11981 | @end smallexample | |
11982 | ||
11983 | @noindent | |
11984 | and you can ask @value{GDBN} to describe the type of @code{s} as shown | |
11985 | below. | |
11986 | ||
11987 | @smallexample | |
11988 | (@value{GDBP}) ptype s | |
11989 | type = POINTER TO ARRAY [-2..2] OF foo = RECORD | |
11990 | f1 : CARDINAL; | |
11991 | f2 : CHAR; | |
11992 | f3 : ARRAY [-2..2] OF CARDINAL; | |
11993 | END | |
11994 | @end smallexample | |
11995 | ||
6d2ebf8b | 11996 | @node M2 Defaults |
79a6e687 | 11997 | @subsubsection Modula-2 Defaults |
c906108c SS |
11998 | @cindex Modula-2 defaults |
11999 | ||
12000 | If type and range checking are set automatically by @value{GDBN}, they | |
12001 | both default to @code{on} whenever the working language changes to | |
d4f3574e | 12002 | Modula-2. This happens regardless of whether you or @value{GDBN} |
c906108c SS |
12003 | selected the working language. |
12004 | ||
12005 | If you allow @value{GDBN} to set the language automatically, then entering | |
12006 | code compiled from a file whose name ends with @file{.mod} sets the | |
79a6e687 BW |
12007 | working language to Modula-2. @xref{Automatically, ,Having @value{GDBN} |
12008 | Infer the Source Language}, for further details. | |
c906108c | 12009 | |
6d2ebf8b | 12010 | @node Deviations |
79a6e687 | 12011 | @subsubsection Deviations from Standard Modula-2 |
c906108c SS |
12012 | @cindex Modula-2, deviations from |
12013 | ||
12014 | A few changes have been made to make Modula-2 programs easier to debug. | |
12015 | This is done primarily via loosening its type strictness: | |
12016 | ||
12017 | @itemize @bullet | |
12018 | @item | |
12019 | Unlike in standard Modula-2, pointer constants can be formed by | |
12020 | integers. This allows you to modify pointer variables during | |
12021 | debugging. (In standard Modula-2, the actual address contained in a | |
12022 | pointer variable is hidden from you; it can only be modified | |
12023 | through direct assignment to another pointer variable or expression that | |
12024 | returned a pointer.) | |
12025 | ||
12026 | @item | |
12027 | C escape sequences can be used in strings and characters to represent | |
12028 | non-printable characters. @value{GDBN} prints out strings with these | |
12029 | escape sequences embedded. Single non-printable characters are | |
12030 | printed using the @samp{CHR(@var{nnn})} format. | |
12031 | ||
12032 | @item | |
12033 | The assignment operator (@code{:=}) returns the value of its right-hand | |
12034 | argument. | |
12035 | ||
12036 | @item | |
12037 | All built-in procedures both modify @emph{and} return their argument. | |
12038 | @end itemize | |
12039 | ||
6d2ebf8b | 12040 | @node M2 Checks |
79a6e687 | 12041 | @subsubsection Modula-2 Type and Range Checks |
c906108c SS |
12042 | @cindex Modula-2 checks |
12043 | ||
12044 | @quotation | |
12045 | @emph{Warning:} in this release, @value{GDBN} does not yet perform type or | |
12046 | range checking. | |
12047 | @end quotation | |
12048 | @c FIXME remove warning when type/range checks added | |
12049 | ||
12050 | @value{GDBN} considers two Modula-2 variables type equivalent if: | |
12051 | ||
12052 | @itemize @bullet | |
12053 | @item | |
12054 | They are of types that have been declared equivalent via a @code{TYPE | |
12055 | @var{t1} = @var{t2}} statement | |
12056 | ||
12057 | @item | |
12058 | They have been declared on the same line. (Note: This is true of the | |
12059 | @sc{gnu} Modula-2 compiler, but it may not be true of other compilers.) | |
12060 | @end itemize | |
12061 | ||
12062 | As long as type checking is enabled, any attempt to combine variables | |
12063 | whose types are not equivalent is an error. | |
12064 | ||
12065 | Range checking is done on all mathematical operations, assignment, array | |
12066 | index bounds, and all built-in functions and procedures. | |
12067 | ||
6d2ebf8b | 12068 | @node M2 Scope |
79a6e687 | 12069 | @subsubsection The Scope Operators @code{::} and @code{.} |
c906108c | 12070 | @cindex scope |
41afff9a | 12071 | @cindex @code{.}, Modula-2 scope operator |
c906108c SS |
12072 | @cindex colon, doubled as scope operator |
12073 | @ifinfo | |
41afff9a | 12074 | @vindex colon-colon@r{, in Modula-2} |
c906108c SS |
12075 | @c Info cannot handle :: but TeX can. |
12076 | @end ifinfo | |
a67ec3f4 | 12077 | @ifnotinfo |
41afff9a | 12078 | @vindex ::@r{, in Modula-2} |
a67ec3f4 | 12079 | @end ifnotinfo |
c906108c SS |
12080 | |
12081 | There are a few subtle differences between the Modula-2 scope operator | |
12082 | (@code{.}) and the @value{GDBN} scope operator (@code{::}). The two have | |
12083 | similar syntax: | |
12084 | ||
474c8240 | 12085 | @smallexample |
c906108c SS |
12086 | |
12087 | @var{module} . @var{id} | |
12088 | @var{scope} :: @var{id} | |
474c8240 | 12089 | @end smallexample |
c906108c SS |
12090 | |
12091 | @noindent | |
12092 | where @var{scope} is the name of a module or a procedure, | |
12093 | @var{module} the name of a module, and @var{id} is any declared | |
12094 | identifier within your program, except another module. | |
12095 | ||
12096 | Using the @code{::} operator makes @value{GDBN} search the scope | |
12097 | specified by @var{scope} for the identifier @var{id}. If it is not | |
12098 | found in the specified scope, then @value{GDBN} searches all scopes | |
12099 | enclosing the one specified by @var{scope}. | |
12100 | ||
12101 | Using the @code{.} operator makes @value{GDBN} search the current scope for | |
12102 | the identifier specified by @var{id} that was imported from the | |
12103 | definition module specified by @var{module}. With this operator, it is | |
12104 | an error if the identifier @var{id} was not imported from definition | |
12105 | module @var{module}, or if @var{id} is not an identifier in | |
12106 | @var{module}. | |
12107 | ||
6d2ebf8b | 12108 | @node GDB/M2 |
c906108c SS |
12109 | @subsubsection @value{GDBN} and Modula-2 |
12110 | ||
12111 | Some @value{GDBN} commands have little use when debugging Modula-2 programs. | |
12112 | Five subcommands of @code{set print} and @code{show print} apply | |
b37052ae | 12113 | specifically to C and C@t{++}: @samp{vtbl}, @samp{demangle}, |
c906108c | 12114 | @samp{asm-demangle}, @samp{object}, and @samp{union}. The first four |
b37052ae | 12115 | apply to C@t{++}, and the last to the C @code{union} type, which has no direct |
c906108c SS |
12116 | analogue in Modula-2. |
12117 | ||
12118 | The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available | |
d4f3574e | 12119 | with any language, is not useful with Modula-2. Its |
c906108c | 12120 | intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be |
b37052ae | 12121 | created in Modula-2 as they can in C or C@t{++}. However, because an |
c906108c | 12122 | address can be specified by an integral constant, the construct |
d4f3574e | 12123 | @samp{@{@var{type}@}@var{adrexp}} is still useful. |
c906108c SS |
12124 | |
12125 | @cindex @code{#} in Modula-2 | |
12126 | In @value{GDBN} scripts, the Modula-2 inequality operator @code{#} is | |
12127 | interpreted as the beginning of a comment. Use @code{<>} instead. | |
c906108c | 12128 | |
e07c999f PH |
12129 | @node Ada |
12130 | @subsection Ada | |
12131 | @cindex Ada | |
12132 | ||
12133 | The extensions made to @value{GDBN} for Ada only support | |
12134 | output from the @sc{gnu} Ada (GNAT) compiler. | |
12135 | Other Ada compilers are not currently supported, and | |
12136 | attempting to debug executables produced by them is most likely | |
12137 | to be difficult. | |
12138 | ||
12139 | ||
12140 | @cindex expressions in Ada | |
12141 | @menu | |
12142 | * Ada Mode Intro:: General remarks on the Ada syntax | |
12143 | and semantics supported by Ada mode | |
12144 | in @value{GDBN}. | |
12145 | * Omissions from Ada:: Restrictions on the Ada expression syntax. | |
12146 | * Additions to Ada:: Extensions of the Ada expression syntax. | |
12147 | * Stopping Before Main Program:: Debugging the program during elaboration. | |
20924a55 JB |
12148 | * Ada Tasks:: Listing and setting breakpoints in tasks. |
12149 | * Ada Tasks and Core Files:: Tasking Support when Debugging Core Files | |
e07c999f PH |
12150 | * Ada Glitches:: Known peculiarities of Ada mode. |
12151 | @end menu | |
12152 | ||
12153 | @node Ada Mode Intro | |
12154 | @subsubsection Introduction | |
12155 | @cindex Ada mode, general | |
12156 | ||
12157 | The Ada mode of @value{GDBN} supports a fairly large subset of Ada expression | |
12158 | syntax, with some extensions. | |
12159 | The philosophy behind the design of this subset is | |
12160 | ||
12161 | @itemize @bullet | |
12162 | @item | |
12163 | That @value{GDBN} should provide basic literals and access to operations for | |
12164 | arithmetic, dereferencing, field selection, indexing, and subprogram calls, | |
12165 | leaving more sophisticated computations to subprograms written into the | |
12166 | program (which therefore may be called from @value{GDBN}). | |
12167 | ||
12168 | @item | |
12169 | That type safety and strict adherence to Ada language restrictions | |
12170 | are not particularly important to the @value{GDBN} user. | |
12171 | ||
12172 | @item | |
12173 | That brevity is important to the @value{GDBN} user. | |
12174 | @end itemize | |
12175 | ||
f3a2dd1a JB |
12176 | Thus, for brevity, the debugger acts as if all names declared in |
12177 | user-written packages are directly visible, even if they are not visible | |
12178 | according to Ada rules, thus making it unnecessary to fully qualify most | |
12179 | names with their packages, regardless of context. Where this causes | |
12180 | ambiguity, @value{GDBN} asks the user's intent. | |
e07c999f PH |
12181 | |
12182 | The debugger will start in Ada mode if it detects an Ada main program. | |
12183 | As for other languages, it will enter Ada mode when stopped in a program that | |
12184 | was translated from an Ada source file. | |
12185 | ||
12186 | While in Ada mode, you may use `@t{--}' for comments. This is useful | |
12187 | mostly for documenting command files. The standard @value{GDBN} comment | |
12188 | (@samp{#}) still works at the beginning of a line in Ada mode, but not in the | |
12189 | middle (to allow based literals). | |
12190 | ||
12191 | The debugger supports limited overloading. Given a subprogram call in which | |
12192 | the function symbol has multiple definitions, it will use the number of | |
12193 | actual parameters and some information about their types to attempt to narrow | |
12194 | the set of definitions. It also makes very limited use of context, preferring | |
12195 | procedures to functions in the context of the @code{call} command, and | |
12196 | functions to procedures elsewhere. | |
12197 | ||
12198 | @node Omissions from Ada | |
12199 | @subsubsection Omissions from Ada | |
12200 | @cindex Ada, omissions from | |
12201 | ||
12202 | Here are the notable omissions from the subset: | |
12203 | ||
12204 | @itemize @bullet | |
12205 | @item | |
12206 | Only a subset of the attributes are supported: | |
12207 | ||
12208 | @itemize @minus | |
12209 | @item | |
12210 | @t{'First}, @t{'Last}, and @t{'Length} | |
12211 | on array objects (not on types and subtypes). | |
12212 | ||
12213 | @item | |
12214 | @t{'Min} and @t{'Max}. | |
12215 | ||
12216 | @item | |
12217 | @t{'Pos} and @t{'Val}. | |
12218 | ||
12219 | @item | |
12220 | @t{'Tag}. | |
12221 | ||
12222 | @item | |
12223 | @t{'Range} on array objects (not subtypes), but only as the right | |
12224 | operand of the membership (@code{in}) operator. | |
12225 | ||
12226 | @item | |
12227 | @t{'Access}, @t{'Unchecked_Access}, and | |
12228 | @t{'Unrestricted_Access} (a GNAT extension). | |
12229 | ||
12230 | @item | |
12231 | @t{'Address}. | |
12232 | @end itemize | |
12233 | ||
12234 | @item | |
12235 | The names in | |
12236 | @code{Characters.Latin_1} are not available and | |
12237 | concatenation is not implemented. Thus, escape characters in strings are | |
12238 | not currently available. | |
12239 | ||
12240 | @item | |
12241 | Equality tests (@samp{=} and @samp{/=}) on arrays test for bitwise | |
12242 | equality of representations. They will generally work correctly | |
12243 | for strings and arrays whose elements have integer or enumeration types. | |
12244 | They may not work correctly for arrays whose element | |
12245 | types have user-defined equality, for arrays of real values | |
12246 | (in particular, IEEE-conformant floating point, because of negative | |
12247 | zeroes and NaNs), and for arrays whose elements contain unused bits with | |
12248 | indeterminate values. | |
12249 | ||
12250 | @item | |
12251 | The other component-by-component array operations (@code{and}, @code{or}, | |
12252 | @code{xor}, @code{not}, and relational tests other than equality) | |
12253 | are not implemented. | |
12254 | ||
12255 | @item | |
860701dc PH |
12256 | @cindex array aggregates (Ada) |
12257 | @cindex record aggregates (Ada) | |
12258 | @cindex aggregates (Ada) | |
12259 | There is limited support for array and record aggregates. They are | |
12260 | permitted only on the right sides of assignments, as in these examples: | |
12261 | ||
12262 | @smallexample | |
077e0a52 JB |
12263 | (@value{GDBP}) set An_Array := (1, 2, 3, 4, 5, 6) |
12264 | (@value{GDBP}) set An_Array := (1, others => 0) | |
12265 | (@value{GDBP}) set An_Array := (0|4 => 1, 1..3 => 2, 5 => 6) | |
12266 | (@value{GDBP}) set A_2D_Array := ((1, 2, 3), (4, 5, 6), (7, 8, 9)) | |
12267 | (@value{GDBP}) set A_Record := (1, "Peter", True); | |
12268 | (@value{GDBP}) set A_Record := (Name => "Peter", Id => 1, Alive => True) | |
860701dc PH |
12269 | @end smallexample |
12270 | ||
12271 | Changing a | |
12272 | discriminant's value by assigning an aggregate has an | |
12273 | undefined effect if that discriminant is used within the record. | |
12274 | However, you can first modify discriminants by directly assigning to | |
12275 | them (which normally would not be allowed in Ada), and then performing an | |
12276 | aggregate assignment. For example, given a variable @code{A_Rec} | |
12277 | declared to have a type such as: | |
12278 | ||
12279 | @smallexample | |
12280 | type Rec (Len : Small_Integer := 0) is record | |
12281 | Id : Integer; | |
12282 | Vals : IntArray (1 .. Len); | |
12283 | end record; | |
12284 | @end smallexample | |
12285 | ||
12286 | you can assign a value with a different size of @code{Vals} with two | |
12287 | assignments: | |
12288 | ||
12289 | @smallexample | |
077e0a52 JB |
12290 | (@value{GDBP}) set A_Rec.Len := 4 |
12291 | (@value{GDBP}) set A_Rec := (Id => 42, Vals => (1, 2, 3, 4)) | |
860701dc PH |
12292 | @end smallexample |
12293 | ||
12294 | As this example also illustrates, @value{GDBN} is very loose about the usual | |
12295 | rules concerning aggregates. You may leave out some of the | |
12296 | components of an array or record aggregate (such as the @code{Len} | |
12297 | component in the assignment to @code{A_Rec} above); they will retain their | |
12298 | original values upon assignment. You may freely use dynamic values as | |
12299 | indices in component associations. You may even use overlapping or | |
12300 | redundant component associations, although which component values are | |
12301 | assigned in such cases is not defined. | |
e07c999f PH |
12302 | |
12303 | @item | |
12304 | Calls to dispatching subprograms are not implemented. | |
12305 | ||
12306 | @item | |
12307 | The overloading algorithm is much more limited (i.e., less selective) | |
ae21e955 BW |
12308 | than that of real Ada. It makes only limited use of the context in |
12309 | which a subexpression appears to resolve its meaning, and it is much | |
12310 | looser in its rules for allowing type matches. As a result, some | |
12311 | function calls will be ambiguous, and the user will be asked to choose | |
12312 | the proper resolution. | |
e07c999f PH |
12313 | |
12314 | @item | |
12315 | The @code{new} operator is not implemented. | |
12316 | ||
12317 | @item | |
12318 | Entry calls are not implemented. | |
12319 | ||
12320 | @item | |
12321 | Aside from printing, arithmetic operations on the native VAX floating-point | |
12322 | formats are not supported. | |
12323 | ||
12324 | @item | |
12325 | It is not possible to slice a packed array. | |
158c7665 PH |
12326 | |
12327 | @item | |
12328 | The names @code{True} and @code{False}, when not part of a qualified name, | |
12329 | are interpreted as if implicitly prefixed by @code{Standard}, regardless of | |
12330 | context. | |
12331 | Should your program | |
12332 | redefine these names in a package or procedure (at best a dubious practice), | |
12333 | you will have to use fully qualified names to access their new definitions. | |
e07c999f PH |
12334 | @end itemize |
12335 | ||
12336 | @node Additions to Ada | |
12337 | @subsubsection Additions to Ada | |
12338 | @cindex Ada, deviations from | |
12339 | ||
12340 | As it does for other languages, @value{GDBN} makes certain generic | |
12341 | extensions to Ada (@pxref{Expressions}): | |
12342 | ||
12343 | @itemize @bullet | |
12344 | @item | |
ae21e955 BW |
12345 | If the expression @var{E} is a variable residing in memory (typically |
12346 | a local variable or array element) and @var{N} is a positive integer, | |
12347 | then @code{@var{E}@@@var{N}} displays the values of @var{E} and the | |
12348 | @var{N}-1 adjacent variables following it in memory as an array. In | |
12349 | Ada, this operator is generally not necessary, since its prime use is | |
12350 | in displaying parts of an array, and slicing will usually do this in | |
12351 | Ada. However, there are occasional uses when debugging programs in | |
12352 | which certain debugging information has been optimized away. | |
e07c999f PH |
12353 | |
12354 | @item | |
ae21e955 BW |
12355 | @code{@var{B}::@var{var}} means ``the variable named @var{var} that |
12356 | appears in function or file @var{B}.'' When @var{B} is a file name, | |
12357 | you must typically surround it in single quotes. | |
e07c999f PH |
12358 | |
12359 | @item | |
12360 | The expression @code{@{@var{type}@} @var{addr}} means ``the variable of type | |
12361 | @var{type} that appears at address @var{addr}.'' | |
12362 | ||
12363 | @item | |
12364 | A name starting with @samp{$} is a convenience variable | |
12365 | (@pxref{Convenience Vars}) or a machine register (@pxref{Registers}). | |
12366 | @end itemize | |
12367 | ||
ae21e955 BW |
12368 | In addition, @value{GDBN} provides a few other shortcuts and outright |
12369 | additions specific to Ada: | |
e07c999f PH |
12370 | |
12371 | @itemize @bullet | |
12372 | @item | |
12373 | The assignment statement is allowed as an expression, returning | |
12374 | its right-hand operand as its value. Thus, you may enter | |
12375 | ||
12376 | @smallexample | |
077e0a52 JB |
12377 | (@value{GDBP}) set x := y + 3 |
12378 | (@value{GDBP}) print A(tmp := y + 1) | |
e07c999f PH |
12379 | @end smallexample |
12380 | ||
12381 | @item | |
12382 | The semicolon is allowed as an ``operator,'' returning as its value | |
12383 | the value of its right-hand operand. | |
12384 | This allows, for example, | |
12385 | complex conditional breaks: | |
12386 | ||
12387 | @smallexample | |
077e0a52 JB |
12388 | (@value{GDBP}) break f |
12389 | (@value{GDBP}) condition 1 (report(i); k += 1; A(k) > 100) | |
e07c999f PH |
12390 | @end smallexample |
12391 | ||
12392 | @item | |
12393 | Rather than use catenation and symbolic character names to introduce special | |
12394 | characters into strings, one may instead use a special bracket notation, | |
12395 | which is also used to print strings. A sequence of characters of the form | |
12396 | @samp{["@var{XX}"]} within a string or character literal denotes the | |
12397 | (single) character whose numeric encoding is @var{XX} in hexadecimal. The | |
12398 | sequence of characters @samp{["""]} also denotes a single quotation mark | |
12399 | in strings. For example, | |
12400 | @smallexample | |
12401 | "One line.["0a"]Next line.["0a"]" | |
12402 | @end smallexample | |
12403 | @noindent | |
ae21e955 BW |
12404 | contains an ASCII newline character (@code{Ada.Characters.Latin_1.LF}) |
12405 | after each period. | |
e07c999f PH |
12406 | |
12407 | @item | |
12408 | The subtype used as a prefix for the attributes @t{'Pos}, @t{'Min}, and | |
12409 | @t{'Max} is optional (and is ignored in any case). For example, it is valid | |
12410 | to write | |
12411 | ||
12412 | @smallexample | |
077e0a52 | 12413 | (@value{GDBP}) print 'max(x, y) |
e07c999f PH |
12414 | @end smallexample |
12415 | ||
12416 | @item | |
12417 | When printing arrays, @value{GDBN} uses positional notation when the | |
12418 | array has a lower bound of 1, and uses a modified named notation otherwise. | |
ae21e955 BW |
12419 | For example, a one-dimensional array of three integers with a lower bound |
12420 | of 3 might print as | |
e07c999f PH |
12421 | |
12422 | @smallexample | |
12423 | (3 => 10, 17, 1) | |
12424 | @end smallexample | |
12425 | ||
12426 | @noindent | |
12427 | That is, in contrast to valid Ada, only the first component has a @code{=>} | |
12428 | clause. | |
12429 | ||
12430 | @item | |
12431 | You may abbreviate attributes in expressions with any unique, | |
12432 | multi-character subsequence of | |
12433 | their names (an exact match gets preference). | |
12434 | For example, you may use @t{a'len}, @t{a'gth}, or @t{a'lh} | |
12435 | in place of @t{a'length}. | |
12436 | ||
12437 | @item | |
12438 | @cindex quoting Ada internal identifiers | |
12439 | Since Ada is case-insensitive, the debugger normally maps identifiers you type | |
12440 | to lower case. The GNAT compiler uses upper-case characters for | |
12441 | some of its internal identifiers, which are normally of no interest to users. | |
12442 | For the rare occasions when you actually have to look at them, | |
12443 | enclose them in angle brackets to avoid the lower-case mapping. | |
12444 | For example, | |
12445 | @smallexample | |
077e0a52 | 12446 | (@value{GDBP}) print <JMPBUF_SAVE>[0] |
e07c999f PH |
12447 | @end smallexample |
12448 | ||
12449 | @item | |
12450 | Printing an object of class-wide type or dereferencing an | |
12451 | access-to-class-wide value will display all the components of the object's | |
12452 | specific type (as indicated by its run-time tag). Likewise, component | |
12453 | selection on such a value will operate on the specific type of the | |
12454 | object. | |
12455 | ||
12456 | @end itemize | |
12457 | ||
12458 | @node Stopping Before Main Program | |
12459 | @subsubsection Stopping at the Very Beginning | |
12460 | ||
12461 | @cindex breakpointing Ada elaboration code | |
12462 | It is sometimes necessary to debug the program during elaboration, and | |
12463 | before reaching the main procedure. | |
12464 | As defined in the Ada Reference | |
12465 | Manual, the elaboration code is invoked from a procedure called | |
12466 | @code{adainit}. To run your program up to the beginning of | |
12467 | elaboration, simply use the following two commands: | |
12468 | @code{tbreak adainit} and @code{run}. | |
12469 | ||
20924a55 JB |
12470 | @node Ada Tasks |
12471 | @subsubsection Extensions for Ada Tasks | |
12472 | @cindex Ada, tasking | |
12473 | ||
12474 | Support for Ada tasks is analogous to that for threads (@pxref{Threads}). | |
12475 | @value{GDBN} provides the following task-related commands: | |
12476 | ||
12477 | @table @code | |
12478 | @kindex info tasks | |
12479 | @item info tasks | |
12480 | This command shows a list of current Ada tasks, as in the following example: | |
12481 | ||
12482 | ||
12483 | @smallexample | |
12484 | @iftex | |
12485 | @leftskip=0.5cm | |
12486 | @end iftex | |
12487 | (@value{GDBP}) info tasks | |
12488 | ID TID P-ID Pri State Name | |
12489 | 1 8088000 0 15 Child Activation Wait main_task | |
12490 | 2 80a4000 1 15 Accept Statement b | |
12491 | 3 809a800 1 15 Child Activation Wait a | |
32cd1edc | 12492 | * 4 80ae800 3 15 Runnable c |
20924a55 JB |
12493 | |
12494 | @end smallexample | |
12495 | ||
12496 | @noindent | |
12497 | In this listing, the asterisk before the last task indicates it to be the | |
12498 | task currently being inspected. | |
12499 | ||
12500 | @table @asis | |
12501 | @item ID | |
12502 | Represents @value{GDBN}'s internal task number. | |
12503 | ||
12504 | @item TID | |
12505 | The Ada task ID. | |
12506 | ||
12507 | @item P-ID | |
12508 | The parent's task ID (@value{GDBN}'s internal task number). | |
12509 | ||
12510 | @item Pri | |
12511 | The base priority of the task. | |
12512 | ||
12513 | @item State | |
12514 | Current state of the task. | |
12515 | ||
12516 | @table @code | |
12517 | @item Unactivated | |
12518 | The task has been created but has not been activated. It cannot be | |
12519 | executing. | |
12520 | ||
20924a55 JB |
12521 | @item Runnable |
12522 | The task is not blocked for any reason known to Ada. (It may be waiting | |
12523 | for a mutex, though.) It is conceptually "executing" in normal mode. | |
12524 | ||
12525 | @item Terminated | |
12526 | The task is terminated, in the sense of ARM 9.3 (5). Any dependents | |
12527 | that were waiting on terminate alternatives have been awakened and have | |
12528 | terminated themselves. | |
12529 | ||
12530 | @item Child Activation Wait | |
12531 | The task is waiting for created tasks to complete activation. | |
12532 | ||
12533 | @item Accept Statement | |
12534 | The task is waiting on an accept or selective wait statement. | |
12535 | ||
12536 | @item Waiting on entry call | |
12537 | The task is waiting on an entry call. | |
12538 | ||
12539 | @item Async Select Wait | |
12540 | The task is waiting to start the abortable part of an asynchronous | |
12541 | select statement. | |
12542 | ||
12543 | @item Delay Sleep | |
12544 | The task is waiting on a select statement with only a delay | |
12545 | alternative open. | |
12546 | ||
12547 | @item Child Termination Wait | |
12548 | The task is sleeping having completed a master within itself, and is | |
12549 | waiting for the tasks dependent on that master to become terminated or | |
12550 | waiting on a terminate Phase. | |
12551 | ||
12552 | @item Wait Child in Term Alt | |
12553 | The task is sleeping waiting for tasks on terminate alternatives to | |
12554 | finish terminating. | |
12555 | ||
12556 | @item Accepting RV with @var{taskno} | |
12557 | The task is accepting a rendez-vous with the task @var{taskno}. | |
12558 | @end table | |
12559 | ||
12560 | @item Name | |
12561 | Name of the task in the program. | |
12562 | ||
12563 | @end table | |
12564 | ||
12565 | @kindex info task @var{taskno} | |
12566 | @item info task @var{taskno} | |
12567 | This command shows detailled informations on the specified task, as in | |
12568 | the following example: | |
12569 | @smallexample | |
12570 | @iftex | |
12571 | @leftskip=0.5cm | |
12572 | @end iftex | |
12573 | (@value{GDBP}) info tasks | |
12574 | ID TID P-ID Pri State Name | |
12575 | 1 8077880 0 15 Child Activation Wait main_task | |
32cd1edc | 12576 | * 2 807c468 1 15 Runnable task_1 |
20924a55 JB |
12577 | (@value{GDBP}) info task 2 |
12578 | Ada Task: 0x807c468 | |
12579 | Name: task_1 | |
12580 | Thread: 0x807f378 | |
12581 | Parent: 1 (main_task) | |
12582 | Base Priority: 15 | |
12583 | State: Runnable | |
12584 | @end smallexample | |
12585 | ||
12586 | @item task | |
12587 | @kindex task@r{ (Ada)} | |
12588 | @cindex current Ada task ID | |
12589 | This command prints the ID of the current task. | |
12590 | ||
12591 | @smallexample | |
12592 | @iftex | |
12593 | @leftskip=0.5cm | |
12594 | @end iftex | |
12595 | (@value{GDBP}) info tasks | |
12596 | ID TID P-ID Pri State Name | |
12597 | 1 8077870 0 15 Child Activation Wait main_task | |
32cd1edc | 12598 | * 2 807c458 1 15 Runnable t |
20924a55 JB |
12599 | (@value{GDBP}) task |
12600 | [Current task is 2] | |
12601 | @end smallexample | |
12602 | ||
12603 | @item task @var{taskno} | |
12604 | @cindex Ada task switching | |
12605 | This command is like the @code{thread @var{threadno}} | |
12606 | command (@pxref{Threads}). It switches the context of debugging | |
12607 | from the current task to the given task. | |
12608 | ||
12609 | @smallexample | |
12610 | @iftex | |
12611 | @leftskip=0.5cm | |
12612 | @end iftex | |
12613 | (@value{GDBP}) info tasks | |
12614 | ID TID P-ID Pri State Name | |
12615 | 1 8077870 0 15 Child Activation Wait main_task | |
32cd1edc | 12616 | * 2 807c458 1 15 Runnable t |
20924a55 JB |
12617 | (@value{GDBP}) task 1 |
12618 | [Switching to task 1] | |
12619 | #0 0x8067726 in pthread_cond_wait () | |
12620 | (@value{GDBP}) bt | |
12621 | #0 0x8067726 in pthread_cond_wait () | |
12622 | #1 0x8056714 in system.os_interface.pthread_cond_wait () | |
12623 | #2 0x805cb63 in system.task_primitives.operations.sleep () | |
12624 | #3 0x806153e in system.tasking.stages.activate_tasks () | |
12625 | #4 0x804aacc in un () at un.adb:5 | |
12626 | @end smallexample | |
12627 | ||
45ac276d JB |
12628 | @item break @var{linespec} task @var{taskno} |
12629 | @itemx break @var{linespec} task @var{taskno} if @dots{} | |
12630 | @cindex breakpoints and tasks, in Ada | |
12631 | @cindex task breakpoints, in Ada | |
12632 | @kindex break @dots{} task @var{taskno}@r{ (Ada)} | |
12633 | These commands are like the @code{break @dots{} thread @dots{}} | |
12634 | command (@pxref{Thread Stops}). | |
12635 | @var{linespec} specifies source lines, as described | |
12636 | in @ref{Specify Location}. | |
12637 | ||
12638 | Use the qualifier @samp{task @var{taskno}} with a breakpoint command | |
12639 | to specify that you only want @value{GDBN} to stop the program when a | |
12640 | particular Ada task reaches this breakpoint. @var{taskno} is one of the | |
12641 | numeric task identifiers assigned by @value{GDBN}, shown in the first | |
12642 | column of the @samp{info tasks} display. | |
12643 | ||
12644 | If you do not specify @samp{task @var{taskno}} when you set a | |
12645 | breakpoint, the breakpoint applies to @emph{all} tasks of your | |
12646 | program. | |
12647 | ||
12648 | You can use the @code{task} qualifier on conditional breakpoints as | |
12649 | well; in this case, place @samp{task @var{taskno}} before the | |
12650 | breakpoint condition (before the @code{if}). | |
12651 | ||
12652 | For example, | |
12653 | ||
12654 | @smallexample | |
12655 | @iftex | |
12656 | @leftskip=0.5cm | |
12657 | @end iftex | |
12658 | (@value{GDBP}) info tasks | |
12659 | ID TID P-ID Pri State Name | |
12660 | 1 140022020 0 15 Child Activation Wait main_task | |
12661 | 2 140045060 1 15 Accept/Select Wait t2 | |
12662 | 3 140044840 1 15 Runnable t1 | |
12663 | * 4 140056040 1 15 Runnable t3 | |
12664 | (@value{GDBP}) b 15 task 2 | |
12665 | Breakpoint 5 at 0x120044cb0: file test_task_debug.adb, line 15. | |
12666 | (@value{GDBP}) cont | |
12667 | Continuing. | |
12668 | task # 1 running | |
12669 | task # 2 running | |
12670 | ||
12671 | Breakpoint 5, test_task_debug () at test_task_debug.adb:15 | |
12672 | 15 flush; | |
12673 | (@value{GDBP}) info tasks | |
12674 | ID TID P-ID Pri State Name | |
12675 | 1 140022020 0 15 Child Activation Wait main_task | |
12676 | * 2 140045060 1 15 Runnable t2 | |
12677 | 3 140044840 1 15 Runnable t1 | |
12678 | 4 140056040 1 15 Delay Sleep t3 | |
12679 | @end smallexample | |
20924a55 JB |
12680 | @end table |
12681 | ||
12682 | @node Ada Tasks and Core Files | |
12683 | @subsubsection Tasking Support when Debugging Core Files | |
12684 | @cindex Ada tasking and core file debugging | |
12685 | ||
12686 | When inspecting a core file, as opposed to debugging a live program, | |
12687 | tasking support may be limited or even unavailable, depending on | |
12688 | the platform being used. | |
12689 | For instance, on x86-linux, the list of tasks is available, but task | |
12690 | switching is not supported. On Tru64, however, task switching will work | |
12691 | as usual. | |
12692 | ||
12693 | On certain platforms, including Tru64, the debugger needs to perform some | |
12694 | memory writes in order to provide Ada tasking support. When inspecting | |
12695 | a core file, this means that the core file must be opened with read-write | |
12696 | privileges, using the command @samp{"set write on"} (@pxref{Patching}). | |
12697 | Under these circumstances, you should make a backup copy of the core | |
12698 | file before inspecting it with @value{GDBN}. | |
12699 | ||
e07c999f PH |
12700 | @node Ada Glitches |
12701 | @subsubsection Known Peculiarities of Ada Mode | |
12702 | @cindex Ada, problems | |
12703 | ||
12704 | Besides the omissions listed previously (@pxref{Omissions from Ada}), | |
12705 | we know of several problems with and limitations of Ada mode in | |
12706 | @value{GDBN}, | |
12707 | some of which will be fixed with planned future releases of the debugger | |
12708 | and the GNU Ada compiler. | |
12709 | ||
12710 | @itemize @bullet | |
12711 | @item | |
12712 | Currently, the debugger | |
12713 | has insufficient information to determine whether certain pointers represent | |
12714 | pointers to objects or the objects themselves. | |
12715 | Thus, the user may have to tack an extra @code{.all} after an expression | |
12716 | to get it printed properly. | |
12717 | ||
12718 | @item | |
12719 | Static constants that the compiler chooses not to materialize as objects in | |
12720 | storage are invisible to the debugger. | |
12721 | ||
12722 | @item | |
12723 | Named parameter associations in function argument lists are ignored (the | |
12724 | argument lists are treated as positional). | |
12725 | ||
12726 | @item | |
12727 | Many useful library packages are currently invisible to the debugger. | |
12728 | ||
12729 | @item | |
12730 | Fixed-point arithmetic, conversions, input, and output is carried out using | |
12731 | floating-point arithmetic, and may give results that only approximate those on | |
12732 | the host machine. | |
12733 | ||
e07c999f PH |
12734 | @item |
12735 | The GNAT compiler never generates the prefix @code{Standard} for any of | |
12736 | the standard symbols defined by the Ada language. @value{GDBN} knows about | |
12737 | this: it will strip the prefix from names when you use it, and will never | |
12738 | look for a name you have so qualified among local symbols, nor match against | |
12739 | symbols in other packages or subprograms. If you have | |
12740 | defined entities anywhere in your program other than parameters and | |
12741 | local variables whose simple names match names in @code{Standard}, | |
12742 | GNAT's lack of qualification here can cause confusion. When this happens, | |
12743 | you can usually resolve the confusion | |
12744 | by qualifying the problematic names with package | |
12745 | @code{Standard} explicitly. | |
12746 | @end itemize | |
12747 | ||
79a6e687 BW |
12748 | @node Unsupported Languages |
12749 | @section Unsupported Languages | |
4e562065 JB |
12750 | |
12751 | @cindex unsupported languages | |
12752 | @cindex minimal language | |
12753 | In addition to the other fully-supported programming languages, | |
12754 | @value{GDBN} also provides a pseudo-language, called @code{minimal}. | |
12755 | It does not represent a real programming language, but provides a set | |
12756 | of capabilities close to what the C or assembly languages provide. | |
12757 | This should allow most simple operations to be performed while debugging | |
12758 | an application that uses a language currently not supported by @value{GDBN}. | |
12759 | ||
12760 | If the language is set to @code{auto}, @value{GDBN} will automatically | |
12761 | select this language if the current frame corresponds to an unsupported | |
12762 | language. | |
12763 | ||
6d2ebf8b | 12764 | @node Symbols |
c906108c SS |
12765 | @chapter Examining the Symbol Table |
12766 | ||
d4f3574e | 12767 | The commands described in this chapter allow you to inquire about the |
c906108c SS |
12768 | symbols (names of variables, functions and types) defined in your |
12769 | program. This information is inherent in the text of your program and | |
12770 | does not change as your program executes. @value{GDBN} finds it in your | |
12771 | program's symbol table, in the file indicated when you started @value{GDBN} | |
79a6e687 BW |
12772 | (@pxref{File Options, ,Choosing Files}), or by one of the |
12773 | file-management commands (@pxref{Files, ,Commands to Specify Files}). | |
c906108c SS |
12774 | |
12775 | @cindex symbol names | |
12776 | @cindex names of symbols | |
12777 | @cindex quoting names | |
12778 | Occasionally, you may need to refer to symbols that contain unusual | |
12779 | characters, which @value{GDBN} ordinarily treats as word delimiters. The | |
12780 | most frequent case is in referring to static variables in other | |
79a6e687 | 12781 | source files (@pxref{Variables,,Program Variables}). File names |
c906108c SS |
12782 | are recorded in object files as debugging symbols, but @value{GDBN} would |
12783 | ordinarily parse a typical file name, like @file{foo.c}, as the three words | |
12784 | @samp{foo} @samp{.} @samp{c}. To allow @value{GDBN} to recognize | |
12785 | @samp{foo.c} as a single symbol, enclose it in single quotes; for example, | |
12786 | ||
474c8240 | 12787 | @smallexample |
c906108c | 12788 | p 'foo.c'::x |
474c8240 | 12789 | @end smallexample |
c906108c SS |
12790 | |
12791 | @noindent | |
12792 | looks up the value of @code{x} in the scope of the file @file{foo.c}. | |
12793 | ||
12794 | @table @code | |
a8f24a35 EZ |
12795 | @cindex case-insensitive symbol names |
12796 | @cindex case sensitivity in symbol names | |
12797 | @kindex set case-sensitive | |
12798 | @item set case-sensitive on | |
12799 | @itemx set case-sensitive off | |
12800 | @itemx set case-sensitive auto | |
12801 | Normally, when @value{GDBN} looks up symbols, it matches their names | |
12802 | with case sensitivity determined by the current source language. | |
12803 | Occasionally, you may wish to control that. The command @code{set | |
12804 | case-sensitive} lets you do that by specifying @code{on} for | |
12805 | case-sensitive matches or @code{off} for case-insensitive ones. If | |
12806 | you specify @code{auto}, case sensitivity is reset to the default | |
12807 | suitable for the source language. The default is case-sensitive | |
12808 | matches for all languages except for Fortran, for which the default is | |
12809 | case-insensitive matches. | |
12810 | ||
9c16f35a EZ |
12811 | @kindex show case-sensitive |
12812 | @item show case-sensitive | |
a8f24a35 EZ |
12813 | This command shows the current setting of case sensitivity for symbols |
12814 | lookups. | |
12815 | ||
c906108c | 12816 | @kindex info address |
b37052ae | 12817 | @cindex address of a symbol |
c906108c SS |
12818 | @item info address @var{symbol} |
12819 | Describe where the data for @var{symbol} is stored. For a register | |
12820 | variable, this says which register it is kept in. For a non-register | |
12821 | local variable, this prints the stack-frame offset at which the variable | |
12822 | is always stored. | |
12823 | ||
12824 | Note the contrast with @samp{print &@var{symbol}}, which does not work | |
12825 | at all for a register variable, and for a stack local variable prints | |
12826 | the exact address of the current instantiation of the variable. | |
12827 | ||
3d67e040 | 12828 | @kindex info symbol |
b37052ae | 12829 | @cindex symbol from address |
9c16f35a | 12830 | @cindex closest symbol and offset for an address |
3d67e040 EZ |
12831 | @item info symbol @var{addr} |
12832 | Print the name of a symbol which is stored at the address @var{addr}. | |
12833 | If no symbol is stored exactly at @var{addr}, @value{GDBN} prints the | |
12834 | nearest symbol and an offset from it: | |
12835 | ||
474c8240 | 12836 | @smallexample |
3d67e040 EZ |
12837 | (@value{GDBP}) info symbol 0x54320 |
12838 | _initialize_vx + 396 in section .text | |
474c8240 | 12839 | @end smallexample |
3d67e040 EZ |
12840 | |
12841 | @noindent | |
12842 | This is the opposite of the @code{info address} command. You can use | |
12843 | it to find out the name of a variable or a function given its address. | |
12844 | ||
c14c28ba PP |
12845 | For dynamically linked executables, the name of executable or shared |
12846 | library containing the symbol is also printed: | |
12847 | ||
12848 | @smallexample | |
12849 | (@value{GDBP}) info symbol 0x400225 | |
12850 | _start + 5 in section .text of /tmp/a.out | |
12851 | (@value{GDBP}) info symbol 0x2aaaac2811cf | |
12852 | __read_nocancel + 6 in section .text of /usr/lib64/libc.so.6 | |
12853 | @end smallexample | |
12854 | ||
c906108c | 12855 | @kindex whatis |
62f3a2ba FF |
12856 | @item whatis [@var{arg}] |
12857 | Print the data type of @var{arg}, which can be either an expression or | |
12858 | a data type. With no argument, print the data type of @code{$}, the | |
12859 | last value in the value history. If @var{arg} is an expression, it is | |
12860 | not actually evaluated, and any side-effecting operations (such as | |
12861 | assignments or function calls) inside it do not take place. If | |
12862 | @var{arg} is a type name, it may be the name of a type or typedef, or | |
12863 | for C code it may have the form @samp{class @var{class-name}}, | |
12864 | @samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or | |
12865 | @samp{enum @var{enum-tag}}. | |
c906108c SS |
12866 | @xref{Expressions, ,Expressions}. |
12867 | ||
c906108c | 12868 | @kindex ptype |
62f3a2ba FF |
12869 | @item ptype [@var{arg}] |
12870 | @code{ptype} accepts the same arguments as @code{whatis}, but prints a | |
12871 | detailed description of the type, instead of just the name of the type. | |
12872 | @xref{Expressions, ,Expressions}. | |
c906108c SS |
12873 | |
12874 | For example, for this variable declaration: | |
12875 | ||
474c8240 | 12876 | @smallexample |
c906108c | 12877 | struct complex @{double real; double imag;@} v; |
474c8240 | 12878 | @end smallexample |
c906108c SS |
12879 | |
12880 | @noindent | |
12881 | the two commands give this output: | |
12882 | ||
474c8240 | 12883 | @smallexample |
c906108c SS |
12884 | @group |
12885 | (@value{GDBP}) whatis v | |
12886 | type = struct complex | |
12887 | (@value{GDBP}) ptype v | |
12888 | type = struct complex @{ | |
12889 | double real; | |
12890 | double imag; | |
12891 | @} | |
12892 | @end group | |
474c8240 | 12893 | @end smallexample |
c906108c SS |
12894 | |
12895 | @noindent | |
12896 | As with @code{whatis}, using @code{ptype} without an argument refers to | |
12897 | the type of @code{$}, the last value in the value history. | |
12898 | ||
ab1adacd EZ |
12899 | @cindex incomplete type |
12900 | Sometimes, programs use opaque data types or incomplete specifications | |
12901 | of complex data structure. If the debug information included in the | |
12902 | program does not allow @value{GDBN} to display a full declaration of | |
12903 | the data type, it will say @samp{<incomplete type>}. For example, | |
12904 | given these declarations: | |
12905 | ||
12906 | @smallexample | |
12907 | struct foo; | |
12908 | struct foo *fooptr; | |
12909 | @end smallexample | |
12910 | ||
12911 | @noindent | |
12912 | but no definition for @code{struct foo} itself, @value{GDBN} will say: | |
12913 | ||
12914 | @smallexample | |
ddb50cd7 | 12915 | (@value{GDBP}) ptype foo |
ab1adacd EZ |
12916 | $1 = <incomplete type> |
12917 | @end smallexample | |
12918 | ||
12919 | @noindent | |
12920 | ``Incomplete type'' is C terminology for data types that are not | |
12921 | completely specified. | |
12922 | ||
c906108c SS |
12923 | @kindex info types |
12924 | @item info types @var{regexp} | |
12925 | @itemx info types | |
09d4efe1 EZ |
12926 | Print a brief description of all types whose names match the regular |
12927 | expression @var{regexp} (or all types in your program, if you supply | |
12928 | no argument). Each complete typename is matched as though it were a | |
12929 | complete line; thus, @samp{i type value} gives information on all | |
12930 | types in your program whose names include the string @code{value}, but | |
12931 | @samp{i type ^value$} gives information only on types whose complete | |
12932 | name is @code{value}. | |
c906108c SS |
12933 | |
12934 | This command differs from @code{ptype} in two ways: first, like | |
12935 | @code{whatis}, it does not print a detailed description; second, it | |
12936 | lists all source files where a type is defined. | |
12937 | ||
b37052ae EZ |
12938 | @kindex info scope |
12939 | @cindex local variables | |
09d4efe1 | 12940 | @item info scope @var{location} |
b37052ae | 12941 | List all the variables local to a particular scope. This command |
09d4efe1 EZ |
12942 | accepts a @var{location} argument---a function name, a source line, or |
12943 | an address preceded by a @samp{*}, and prints all the variables local | |
2a25a5ba EZ |
12944 | to the scope defined by that location. (@xref{Specify Location}, for |
12945 | details about supported forms of @var{location}.) For example: | |
b37052ae EZ |
12946 | |
12947 | @smallexample | |
12948 | (@value{GDBP}) @b{info scope command_line_handler} | |
12949 | Scope for command_line_handler: | |
12950 | Symbol rl is an argument at stack/frame offset 8, length 4. | |
12951 | Symbol linebuffer is in static storage at address 0x150a18, length 4. | |
12952 | Symbol linelength is in static storage at address 0x150a1c, length 4. | |
12953 | Symbol p is a local variable in register $esi, length 4. | |
12954 | Symbol p1 is a local variable in register $ebx, length 4. | |
12955 | Symbol nline is a local variable in register $edx, length 4. | |
12956 | Symbol repeat is a local variable at frame offset -8, length 4. | |
12957 | @end smallexample | |
12958 | ||
f5c37c66 EZ |
12959 | @noindent |
12960 | This command is especially useful for determining what data to collect | |
12961 | during a @dfn{trace experiment}, see @ref{Tracepoint Actions, | |
12962 | collect}. | |
12963 | ||
c906108c SS |
12964 | @kindex info source |
12965 | @item info source | |
919d772c JB |
12966 | Show information about the current source file---that is, the source file for |
12967 | the function containing the current point of execution: | |
12968 | @itemize @bullet | |
12969 | @item | |
12970 | the name of the source file, and the directory containing it, | |
12971 | @item | |
12972 | the directory it was compiled in, | |
12973 | @item | |
12974 | its length, in lines, | |
12975 | @item | |
12976 | which programming language it is written in, | |
12977 | @item | |
12978 | whether the executable includes debugging information for that file, and | |
12979 | if so, what format the information is in (e.g., STABS, Dwarf 2, etc.), and | |
12980 | @item | |
12981 | whether the debugging information includes information about | |
12982 | preprocessor macros. | |
12983 | @end itemize | |
12984 | ||
c906108c SS |
12985 | |
12986 | @kindex info sources | |
12987 | @item info sources | |
12988 | Print the names of all source files in your program for which there is | |
12989 | debugging information, organized into two lists: files whose symbols | |
12990 | have already been read, and files whose symbols will be read when needed. | |
12991 | ||
12992 | @kindex info functions | |
12993 | @item info functions | |
12994 | Print the names and data types of all defined functions. | |
12995 | ||
12996 | @item info functions @var{regexp} | |
12997 | Print the names and data types of all defined functions | |
12998 | whose names contain a match for regular expression @var{regexp}. | |
12999 | Thus, @samp{info fun step} finds all functions whose names | |
13000 | include @code{step}; @samp{info fun ^step} finds those whose names | |
b383017d | 13001 | start with @code{step}. If a function name contains characters |
c1468174 | 13002 | that conflict with the regular expression language (e.g.@: |
1c5dfdad | 13003 | @samp{operator*()}), they may be quoted with a backslash. |
c906108c SS |
13004 | |
13005 | @kindex info variables | |
13006 | @item info variables | |
0fe7935b | 13007 | Print the names and data types of all variables that are defined |
6ca652b0 | 13008 | outside of functions (i.e.@: excluding local variables). |
c906108c SS |
13009 | |
13010 | @item info variables @var{regexp} | |
13011 | Print the names and data types of all variables (except for local | |
13012 | variables) whose names contain a match for regular expression | |
13013 | @var{regexp}. | |
13014 | ||
b37303ee | 13015 | @kindex info classes |
721c2651 | 13016 | @cindex Objective-C, classes and selectors |
b37303ee AF |
13017 | @item info classes |
13018 | @itemx info classes @var{regexp} | |
13019 | Display all Objective-C classes in your program, or | |
13020 | (with the @var{regexp} argument) all those matching a particular regular | |
13021 | expression. | |
13022 | ||
13023 | @kindex info selectors | |
13024 | @item info selectors | |
13025 | @itemx info selectors @var{regexp} | |
13026 | Display all Objective-C selectors in your program, or | |
13027 | (with the @var{regexp} argument) all those matching a particular regular | |
13028 | expression. | |
13029 | ||
c906108c SS |
13030 | @ignore |
13031 | This was never implemented. | |
13032 | @kindex info methods | |
13033 | @item info methods | |
13034 | @itemx info methods @var{regexp} | |
13035 | The @code{info methods} command permits the user to examine all defined | |
b37052ae EZ |
13036 | methods within C@t{++} program, or (with the @var{regexp} argument) a |
13037 | specific set of methods found in the various C@t{++} classes. Many | |
13038 | C@t{++} classes provide a large number of methods. Thus, the output | |
c906108c SS |
13039 | from the @code{ptype} command can be overwhelming and hard to use. The |
13040 | @code{info-methods} command filters the methods, printing only those | |
13041 | which match the regular-expression @var{regexp}. | |
13042 | @end ignore | |
13043 | ||
c906108c SS |
13044 | @cindex reloading symbols |
13045 | Some systems allow individual object files that make up your program to | |
7a292a7a SS |
13046 | be replaced without stopping and restarting your program. For example, |
13047 | in VxWorks you can simply recompile a defective object file and keep on | |
13048 | running. If you are running on one of these systems, you can allow | |
13049 | @value{GDBN} to reload the symbols for automatically relinked modules: | |
c906108c SS |
13050 | |
13051 | @table @code | |
13052 | @kindex set symbol-reloading | |
13053 | @item set symbol-reloading on | |
13054 | Replace symbol definitions for the corresponding source file when an | |
13055 | object file with a particular name is seen again. | |
13056 | ||
13057 | @item set symbol-reloading off | |
6d2ebf8b SS |
13058 | Do not replace symbol definitions when encountering object files of the |
13059 | same name more than once. This is the default state; if you are not | |
13060 | running on a system that permits automatic relinking of modules, you | |
13061 | should leave @code{symbol-reloading} off, since otherwise @value{GDBN} | |
13062 | may discard symbols when linking large programs, that may contain | |
13063 | several modules (from different directories or libraries) with the same | |
13064 | name. | |
c906108c SS |
13065 | |
13066 | @kindex show symbol-reloading | |
13067 | @item show symbol-reloading | |
13068 | Show the current @code{on} or @code{off} setting. | |
13069 | @end table | |
c906108c | 13070 | |
9c16f35a | 13071 | @cindex opaque data types |
c906108c SS |
13072 | @kindex set opaque-type-resolution |
13073 | @item set opaque-type-resolution on | |
13074 | Tell @value{GDBN} to resolve opaque types. An opaque type is a type | |
13075 | declared as a pointer to a @code{struct}, @code{class}, or | |
13076 | @code{union}---for example, @code{struct MyType *}---that is used in one | |
13077 | source file although the full declaration of @code{struct MyType} is in | |
13078 | another source file. The default is on. | |
13079 | ||
13080 | A change in the setting of this subcommand will not take effect until | |
13081 | the next time symbols for a file are loaded. | |
13082 | ||
13083 | @item set opaque-type-resolution off | |
13084 | Tell @value{GDBN} not to resolve opaque types. In this case, the type | |
13085 | is printed as follows: | |
13086 | @smallexample | |
13087 | @{<no data fields>@} | |
13088 | @end smallexample | |
13089 | ||
13090 | @kindex show opaque-type-resolution | |
13091 | @item show opaque-type-resolution | |
13092 | Show whether opaque types are resolved or not. | |
c906108c SS |
13093 | |
13094 | @kindex maint print symbols | |
13095 | @cindex symbol dump | |
13096 | @kindex maint print psymbols | |
13097 | @cindex partial symbol dump | |
13098 | @item maint print symbols @var{filename} | |
13099 | @itemx maint print psymbols @var{filename} | |
13100 | @itemx maint print msymbols @var{filename} | |
13101 | Write a dump of debugging symbol data into the file @var{filename}. | |
13102 | These commands are used to debug the @value{GDBN} symbol-reading code. Only | |
13103 | symbols with debugging data are included. If you use @samp{maint print | |
13104 | symbols}, @value{GDBN} includes all the symbols for which it has already | |
13105 | collected full details: that is, @var{filename} reflects symbols for | |
13106 | only those files whose symbols @value{GDBN} has read. You can use the | |
13107 | command @code{info sources} to find out which files these are. If you | |
13108 | use @samp{maint print psymbols} instead, the dump shows information about | |
13109 | symbols that @value{GDBN} only knows partially---that is, symbols defined in | |
13110 | files that @value{GDBN} has skimmed, but not yet read completely. Finally, | |
13111 | @samp{maint print msymbols} dumps just the minimal symbol information | |
13112 | required for each object file from which @value{GDBN} has read some symbols. | |
79a6e687 | 13113 | @xref{Files, ,Commands to Specify Files}, for a discussion of how |
c906108c | 13114 | @value{GDBN} reads symbols (in the description of @code{symbol-file}). |
44ea7b70 | 13115 | |
5e7b2f39 JB |
13116 | @kindex maint info symtabs |
13117 | @kindex maint info psymtabs | |
44ea7b70 JB |
13118 | @cindex listing @value{GDBN}'s internal symbol tables |
13119 | @cindex symbol tables, listing @value{GDBN}'s internal | |
13120 | @cindex full symbol tables, listing @value{GDBN}'s internal | |
13121 | @cindex partial symbol tables, listing @value{GDBN}'s internal | |
5e7b2f39 JB |
13122 | @item maint info symtabs @r{[} @var{regexp} @r{]} |
13123 | @itemx maint info psymtabs @r{[} @var{regexp} @r{]} | |
44ea7b70 JB |
13124 | |
13125 | List the @code{struct symtab} or @code{struct partial_symtab} | |
13126 | structures whose names match @var{regexp}. If @var{regexp} is not | |
13127 | given, list them all. The output includes expressions which you can | |
13128 | copy into a @value{GDBN} debugging this one to examine a particular | |
13129 | structure in more detail. For example: | |
13130 | ||
13131 | @smallexample | |
5e7b2f39 | 13132 | (@value{GDBP}) maint info psymtabs dwarf2read |
44ea7b70 JB |
13133 | @{ objfile /home/gnu/build/gdb/gdb |
13134 | ((struct objfile *) 0x82e69d0) | |
b383017d | 13135 | @{ psymtab /home/gnu/src/gdb/dwarf2read.c |
44ea7b70 JB |
13136 | ((struct partial_symtab *) 0x8474b10) |
13137 | readin no | |
13138 | fullname (null) | |
13139 | text addresses 0x814d3c8 -- 0x8158074 | |
13140 | globals (* (struct partial_symbol **) 0x8507a08 @@ 9) | |
13141 | statics (* (struct partial_symbol **) 0x40e95b78 @@ 2882) | |
13142 | dependencies (none) | |
13143 | @} | |
13144 | @} | |
5e7b2f39 | 13145 | (@value{GDBP}) maint info symtabs |
44ea7b70 JB |
13146 | (@value{GDBP}) |
13147 | @end smallexample | |
13148 | @noindent | |
13149 | We see that there is one partial symbol table whose filename contains | |
13150 | the string @samp{dwarf2read}, belonging to the @samp{gdb} executable; | |
13151 | and we see that @value{GDBN} has not read in any symtabs yet at all. | |
13152 | If we set a breakpoint on a function, that will cause @value{GDBN} to | |
13153 | read the symtab for the compilation unit containing that function: | |
13154 | ||
13155 | @smallexample | |
13156 | (@value{GDBP}) break dwarf2_psymtab_to_symtab | |
13157 | Breakpoint 1 at 0x814e5da: file /home/gnu/src/gdb/dwarf2read.c, | |
13158 | line 1574. | |
5e7b2f39 | 13159 | (@value{GDBP}) maint info symtabs |
b383017d | 13160 | @{ objfile /home/gnu/build/gdb/gdb |
44ea7b70 | 13161 | ((struct objfile *) 0x82e69d0) |
b383017d | 13162 | @{ symtab /home/gnu/src/gdb/dwarf2read.c |
44ea7b70 JB |
13163 | ((struct symtab *) 0x86c1f38) |
13164 | dirname (null) | |
13165 | fullname (null) | |
13166 | blockvector ((struct blockvector *) 0x86c1bd0) (primary) | |
1b39d5c0 | 13167 | linetable ((struct linetable *) 0x8370fa0) |
44ea7b70 JB |
13168 | debugformat DWARF 2 |
13169 | @} | |
13170 | @} | |
b383017d | 13171 | (@value{GDBP}) |
44ea7b70 | 13172 | @end smallexample |
c906108c SS |
13173 | @end table |
13174 | ||
44ea7b70 | 13175 | |
6d2ebf8b | 13176 | @node Altering |
c906108c SS |
13177 | @chapter Altering Execution |
13178 | ||
13179 | Once you think you have found an error in your program, you might want to | |
13180 | find out for certain whether correcting the apparent error would lead to | |
13181 | correct results in the rest of the run. You can find the answer by | |
13182 | experiment, using the @value{GDBN} features for altering execution of the | |
13183 | program. | |
13184 | ||
13185 | For example, you can store new values into variables or memory | |
7a292a7a SS |
13186 | locations, give your program a signal, restart it at a different |
13187 | address, or even return prematurely from a function. | |
c906108c SS |
13188 | |
13189 | @menu | |
13190 | * Assignment:: Assignment to variables | |
13191 | * Jumping:: Continuing at a different address | |
c906108c | 13192 | * Signaling:: Giving your program a signal |
c906108c SS |
13193 | * Returning:: Returning from a function |
13194 | * Calling:: Calling your program's functions | |
13195 | * Patching:: Patching your program | |
13196 | @end menu | |
13197 | ||
6d2ebf8b | 13198 | @node Assignment |
79a6e687 | 13199 | @section Assignment to Variables |
c906108c SS |
13200 | |
13201 | @cindex assignment | |
13202 | @cindex setting variables | |
13203 | To alter the value of a variable, evaluate an assignment expression. | |
13204 | @xref{Expressions, ,Expressions}. For example, | |
13205 | ||
474c8240 | 13206 | @smallexample |
c906108c | 13207 | print x=4 |
474c8240 | 13208 | @end smallexample |
c906108c SS |
13209 | |
13210 | @noindent | |
13211 | stores the value 4 into the variable @code{x}, and then prints the | |
5d161b24 | 13212 | value of the assignment expression (which is 4). |
c906108c SS |
13213 | @xref{Languages, ,Using @value{GDBN} with Different Languages}, for more |
13214 | information on operators in supported languages. | |
c906108c SS |
13215 | |
13216 | @kindex set variable | |
13217 | @cindex variables, setting | |
13218 | If you are not interested in seeing the value of the assignment, use the | |
13219 | @code{set} command instead of the @code{print} command. @code{set} is | |
13220 | really the same as @code{print} except that the expression's value is | |
13221 | not printed and is not put in the value history (@pxref{Value History, | |
79a6e687 | 13222 | ,Value History}). The expression is evaluated only for its effects. |
c906108c | 13223 | |
c906108c SS |
13224 | If the beginning of the argument string of the @code{set} command |
13225 | appears identical to a @code{set} subcommand, use the @code{set | |
13226 | variable} command instead of just @code{set}. This command is identical | |
13227 | to @code{set} except for its lack of subcommands. For example, if your | |
13228 | program has a variable @code{width}, you get an error if you try to set | |
13229 | a new value with just @samp{set width=13}, because @value{GDBN} has the | |
13230 | command @code{set width}: | |
13231 | ||
474c8240 | 13232 | @smallexample |
c906108c SS |
13233 | (@value{GDBP}) whatis width |
13234 | type = double | |
13235 | (@value{GDBP}) p width | |
13236 | $4 = 13 | |
13237 | (@value{GDBP}) set width=47 | |
13238 | Invalid syntax in expression. | |
474c8240 | 13239 | @end smallexample |
c906108c SS |
13240 | |
13241 | @noindent | |
13242 | The invalid expression, of course, is @samp{=47}. In | |
13243 | order to actually set the program's variable @code{width}, use | |
13244 | ||
474c8240 | 13245 | @smallexample |
c906108c | 13246 | (@value{GDBP}) set var width=47 |
474c8240 | 13247 | @end smallexample |
53a5351d | 13248 | |
c906108c SS |
13249 | Because the @code{set} command has many subcommands that can conflict |
13250 | with the names of program variables, it is a good idea to use the | |
13251 | @code{set variable} command instead of just @code{set}. For example, if | |
13252 | your program has a variable @code{g}, you run into problems if you try | |
13253 | to set a new value with just @samp{set g=4}, because @value{GDBN} has | |
13254 | the command @code{set gnutarget}, abbreviated @code{set g}: | |
13255 | ||
474c8240 | 13256 | @smallexample |
c906108c SS |
13257 | @group |
13258 | (@value{GDBP}) whatis g | |
13259 | type = double | |
13260 | (@value{GDBP}) p g | |
13261 | $1 = 1 | |
13262 | (@value{GDBP}) set g=4 | |
2df3850c | 13263 | (@value{GDBP}) p g |
c906108c SS |
13264 | $2 = 1 |
13265 | (@value{GDBP}) r | |
13266 | The program being debugged has been started already. | |
13267 | Start it from the beginning? (y or n) y | |
13268 | Starting program: /home/smith/cc_progs/a.out | |
6d2ebf8b SS |
13269 | "/home/smith/cc_progs/a.out": can't open to read symbols: |
13270 | Invalid bfd target. | |
c906108c SS |
13271 | (@value{GDBP}) show g |
13272 | The current BFD target is "=4". | |
13273 | @end group | |
474c8240 | 13274 | @end smallexample |
c906108c SS |
13275 | |
13276 | @noindent | |
13277 | The program variable @code{g} did not change, and you silently set the | |
13278 | @code{gnutarget} to an invalid value. In order to set the variable | |
13279 | @code{g}, use | |
13280 | ||
474c8240 | 13281 | @smallexample |
c906108c | 13282 | (@value{GDBP}) set var g=4 |
474c8240 | 13283 | @end smallexample |
c906108c SS |
13284 | |
13285 | @value{GDBN} allows more implicit conversions in assignments than C; you can | |
13286 | freely store an integer value into a pointer variable or vice versa, | |
13287 | and you can convert any structure to any other structure that is the | |
13288 | same length or shorter. | |
13289 | @comment FIXME: how do structs align/pad in these conversions? | |
13290 | @comment /doc@cygnus.com 18dec1990 | |
13291 | ||
13292 | To store values into arbitrary places in memory, use the @samp{@{@dots{}@}} | |
13293 | construct to generate a value of specified type at a specified address | |
13294 | (@pxref{Expressions, ,Expressions}). For example, @code{@{int@}0x83040} refers | |
13295 | to memory location @code{0x83040} as an integer (which implies a certain size | |
13296 | and representation in memory), and | |
13297 | ||
474c8240 | 13298 | @smallexample |
c906108c | 13299 | set @{int@}0x83040 = 4 |
474c8240 | 13300 | @end smallexample |
c906108c SS |
13301 | |
13302 | @noindent | |
13303 | stores the value 4 into that memory location. | |
13304 | ||
6d2ebf8b | 13305 | @node Jumping |
79a6e687 | 13306 | @section Continuing at a Different Address |
c906108c SS |
13307 | |
13308 | Ordinarily, when you continue your program, you do so at the place where | |
13309 | it stopped, with the @code{continue} command. You can instead continue at | |
13310 | an address of your own choosing, with the following commands: | |
13311 | ||
13312 | @table @code | |
13313 | @kindex jump | |
13314 | @item jump @var{linespec} | |
2a25a5ba EZ |
13315 | @itemx jump @var{location} |
13316 | Resume execution at line @var{linespec} or at address given by | |
13317 | @var{location}. Execution stops again immediately if there is a | |
13318 | breakpoint there. @xref{Specify Location}, for a description of the | |
13319 | different forms of @var{linespec} and @var{location}. It is common | |
13320 | practice to use the @code{tbreak} command in conjunction with | |
13321 | @code{jump}. @xref{Set Breaks, ,Setting Breakpoints}. | |
c906108c SS |
13322 | |
13323 | The @code{jump} command does not change the current stack frame, or | |
13324 | the stack pointer, or the contents of any memory location or any | |
13325 | register other than the program counter. If line @var{linespec} is in | |
13326 | a different function from the one currently executing, the results may | |
13327 | be bizarre if the two functions expect different patterns of arguments or | |
13328 | of local variables. For this reason, the @code{jump} command requests | |
13329 | confirmation if the specified line is not in the function currently | |
13330 | executing. However, even bizarre results are predictable if you are | |
13331 | well acquainted with the machine-language code of your program. | |
c906108c SS |
13332 | @end table |
13333 | ||
c906108c | 13334 | @c Doesn't work on HP-UX; have to set $pcoqh and $pcoqt. |
53a5351d JM |
13335 | On many systems, you can get much the same effect as the @code{jump} |
13336 | command by storing a new value into the register @code{$pc}. The | |
13337 | difference is that this does not start your program running; it only | |
13338 | changes the address of where it @emph{will} run when you continue. For | |
13339 | example, | |
c906108c | 13340 | |
474c8240 | 13341 | @smallexample |
c906108c | 13342 | set $pc = 0x485 |
474c8240 | 13343 | @end smallexample |
c906108c SS |
13344 | |
13345 | @noindent | |
13346 | makes the next @code{continue} command or stepping command execute at | |
13347 | address @code{0x485}, rather than at the address where your program stopped. | |
79a6e687 | 13348 | @xref{Continuing and Stepping, ,Continuing and Stepping}. |
c906108c SS |
13349 | |
13350 | The most common occasion to use the @code{jump} command is to back | |
13351 | up---perhaps with more breakpoints set---over a portion of a program | |
13352 | that has already executed, in order to examine its execution in more | |
13353 | detail. | |
13354 | ||
c906108c | 13355 | @c @group |
6d2ebf8b | 13356 | @node Signaling |
79a6e687 | 13357 | @section Giving your Program a Signal |
9c16f35a | 13358 | @cindex deliver a signal to a program |
c906108c SS |
13359 | |
13360 | @table @code | |
13361 | @kindex signal | |
13362 | @item signal @var{signal} | |
13363 | Resume execution where your program stopped, but immediately give it the | |
13364 | signal @var{signal}. @var{signal} can be the name or the number of a | |
13365 | signal. For example, on many systems @code{signal 2} and @code{signal | |
13366 | SIGINT} are both ways of sending an interrupt signal. | |
13367 | ||
13368 | Alternatively, if @var{signal} is zero, continue execution without | |
13369 | giving a signal. This is useful when your program stopped on account of | |
13370 | a signal and would ordinary see the signal when resumed with the | |
13371 | @code{continue} command; @samp{signal 0} causes it to resume without a | |
13372 | signal. | |
13373 | ||
13374 | @code{signal} does not repeat when you press @key{RET} a second time | |
13375 | after executing the command. | |
13376 | @end table | |
13377 | @c @end group | |
13378 | ||
13379 | Invoking the @code{signal} command is not the same as invoking the | |
13380 | @code{kill} utility from the shell. Sending a signal with @code{kill} | |
13381 | causes @value{GDBN} to decide what to do with the signal depending on | |
13382 | the signal handling tables (@pxref{Signals}). The @code{signal} command | |
13383 | passes the signal directly to your program. | |
13384 | ||
c906108c | 13385 | |
6d2ebf8b | 13386 | @node Returning |
79a6e687 | 13387 | @section Returning from a Function |
c906108c SS |
13388 | |
13389 | @table @code | |
13390 | @cindex returning from a function | |
13391 | @kindex return | |
13392 | @item return | |
13393 | @itemx return @var{expression} | |
13394 | You can cancel execution of a function call with the @code{return} | |
13395 | command. If you give an | |
13396 | @var{expression} argument, its value is used as the function's return | |
13397 | value. | |
13398 | @end table | |
13399 | ||
13400 | When you use @code{return}, @value{GDBN} discards the selected stack frame | |
13401 | (and all frames within it). You can think of this as making the | |
13402 | discarded frame return prematurely. If you wish to specify a value to | |
13403 | be returned, give that value as the argument to @code{return}. | |
13404 | ||
13405 | This pops the selected stack frame (@pxref{Selection, ,Selecting a | |
79a6e687 | 13406 | Frame}), and any other frames inside of it, leaving its caller as the |
c906108c SS |
13407 | innermost remaining frame. That frame becomes selected. The |
13408 | specified value is stored in the registers used for returning values | |
13409 | of functions. | |
13410 | ||
13411 | The @code{return} command does not resume execution; it leaves the | |
13412 | program stopped in the state that would exist if the function had just | |
13413 | returned. In contrast, the @code{finish} command (@pxref{Continuing | |
79a6e687 | 13414 | and Stepping, ,Continuing and Stepping}) resumes execution until the |
c906108c SS |
13415 | selected stack frame returns naturally. |
13416 | ||
61ff14c6 JK |
13417 | @value{GDBN} needs to know how the @var{expression} argument should be set for |
13418 | the inferior. The concrete registers assignment depends on the OS ABI and the | |
13419 | type being returned by the selected stack frame. For example it is common for | |
13420 | OS ABI to return floating point values in FPU registers while integer values in | |
13421 | CPU registers. Still some ABIs return even floating point values in CPU | |
13422 | registers. Larger integer widths (such as @code{long long int}) also have | |
13423 | specific placement rules. @value{GDBN} already knows the OS ABI from its | |
13424 | current target so it needs to find out also the type being returned to make the | |
13425 | assignment into the right register(s). | |
13426 | ||
13427 | Normally, the selected stack frame has debug info. @value{GDBN} will always | |
13428 | use the debug info instead of the implicit type of @var{expression} when the | |
13429 | debug info is available. For example, if you type @kbd{return -1}, and the | |
13430 | function in the current stack frame is declared to return a @code{long long | |
13431 | int}, @value{GDBN} transparently converts the implicit @code{int} value of -1 | |
13432 | into a @code{long long int}: | |
13433 | ||
13434 | @smallexample | |
13435 | Breakpoint 1, func () at gdb.base/return-nodebug.c:29 | |
13436 | 29 return 31; | |
13437 | (@value{GDBP}) return -1 | |
13438 | Make func return now? (y or n) y | |
13439 | #0 0x004004f6 in main () at gdb.base/return-nodebug.c:43 | |
13440 | 43 printf ("result=%lld\n", func ()); | |
13441 | (@value{GDBP}) | |
13442 | @end smallexample | |
13443 | ||
13444 | However, if the selected stack frame does not have a debug info, e.g., if the | |
13445 | function was compiled without debug info, @value{GDBN} has to find out the type | |
13446 | to return from user. Specifying a different type by mistake may set the value | |
13447 | in different inferior registers than the caller code expects. For example, | |
13448 | typing @kbd{return -1} with its implicit type @code{int} would set only a part | |
13449 | of a @code{long long int} result for a debug info less function (on 32-bit | |
13450 | architectures). Therefore the user is required to specify the return type by | |
13451 | an appropriate cast explicitly: | |
13452 | ||
13453 | @smallexample | |
13454 | Breakpoint 2, 0x0040050b in func () | |
13455 | (@value{GDBP}) return -1 | |
13456 | Return value type not available for selected stack frame. | |
13457 | Please use an explicit cast of the value to return. | |
13458 | (@value{GDBP}) return (long long int) -1 | |
13459 | Make selected stack frame return now? (y or n) y | |
13460 | #0 0x00400526 in main () | |
13461 | (@value{GDBP}) | |
13462 | @end smallexample | |
13463 | ||
6d2ebf8b | 13464 | @node Calling |
79a6e687 | 13465 | @section Calling Program Functions |
c906108c | 13466 | |
f8568604 | 13467 | @table @code |
c906108c | 13468 | @cindex calling functions |
f8568604 EZ |
13469 | @cindex inferior functions, calling |
13470 | @item print @var{expr} | |
d3e8051b | 13471 | Evaluate the expression @var{expr} and display the resulting value. |
f8568604 EZ |
13472 | @var{expr} may include calls to functions in the program being |
13473 | debugged. | |
13474 | ||
c906108c | 13475 | @kindex call |
c906108c SS |
13476 | @item call @var{expr} |
13477 | Evaluate the expression @var{expr} without displaying @code{void} | |
13478 | returned values. | |
c906108c SS |
13479 | |
13480 | You can use this variant of the @code{print} command if you want to | |
f8568604 EZ |
13481 | execute a function from your program that does not return anything |
13482 | (a.k.a.@: @dfn{a void function}), but without cluttering the output | |
13483 | with @code{void} returned values that @value{GDBN} will otherwise | |
13484 | print. If the result is not void, it is printed and saved in the | |
13485 | value history. | |
13486 | @end table | |
13487 | ||
9c16f35a EZ |
13488 | It is possible for the function you call via the @code{print} or |
13489 | @code{call} command to generate a signal (e.g., if there's a bug in | |
13490 | the function, or if you passed it incorrect arguments). What happens | |
13491 | in that case is controlled by the @code{set unwindonsignal} command. | |
13492 | ||
7cd1089b PM |
13493 | Similarly, with a C@t{++} program it is possible for the function you |
13494 | call via the @code{print} or @code{call} command to generate an | |
13495 | exception that is not handled due to the constraints of the dummy | |
13496 | frame. In this case, any exception that is raised in the frame, but has | |
13497 | an out-of-frame exception handler will not be found. GDB builds a | |
13498 | dummy-frame for the inferior function call, and the unwinder cannot | |
13499 | seek for exception handlers outside of this dummy-frame. What happens | |
13500 | in that case is controlled by the | |
13501 | @code{set unwind-on-terminating-exception} command. | |
13502 | ||
9c16f35a EZ |
13503 | @table @code |
13504 | @item set unwindonsignal | |
13505 | @kindex set unwindonsignal | |
13506 | @cindex unwind stack in called functions | |
13507 | @cindex call dummy stack unwinding | |
13508 | Set unwinding of the stack if a signal is received while in a function | |
13509 | that @value{GDBN} called in the program being debugged. If set to on, | |
13510 | @value{GDBN} unwinds the stack it created for the call and restores | |
13511 | the context to what it was before the call. If set to off (the | |
13512 | default), @value{GDBN} stops in the frame where the signal was | |
13513 | received. | |
13514 | ||
13515 | @item show unwindonsignal | |
13516 | @kindex show unwindonsignal | |
13517 | Show the current setting of stack unwinding in the functions called by | |
13518 | @value{GDBN}. | |
7cd1089b PM |
13519 | |
13520 | @item set unwind-on-terminating-exception | |
13521 | @kindex set unwind-on-terminating-exception | |
13522 | @cindex unwind stack in called functions with unhandled exceptions | |
13523 | @cindex call dummy stack unwinding on unhandled exception. | |
13524 | Set unwinding of the stack if a C@t{++} exception is raised, but left | |
13525 | unhandled while in a function that @value{GDBN} called in the program being | |
13526 | debugged. If set to on (the default), @value{GDBN} unwinds the stack | |
13527 | it created for the call and restores the context to what it was before | |
13528 | the call. If set to off, @value{GDBN} the exception is delivered to | |
13529 | the default C@t{++} exception handler and the inferior terminated. | |
13530 | ||
13531 | @item show unwind-on-terminating-exception | |
13532 | @kindex show unwind-on-terminating-exception | |
13533 | Show the current setting of stack unwinding in the functions called by | |
13534 | @value{GDBN}. | |
13535 | ||
9c16f35a EZ |
13536 | @end table |
13537 | ||
f8568604 EZ |
13538 | @cindex weak alias functions |
13539 | Sometimes, a function you wish to call is actually a @dfn{weak alias} | |
13540 | for another function. In such case, @value{GDBN} might not pick up | |
13541 | the type information, including the types of the function arguments, | |
13542 | which causes @value{GDBN} to call the inferior function incorrectly. | |
13543 | As a result, the called function will function erroneously and may | |
13544 | even crash. A solution to that is to use the name of the aliased | |
13545 | function instead. | |
c906108c | 13546 | |
6d2ebf8b | 13547 | @node Patching |
79a6e687 | 13548 | @section Patching Programs |
7a292a7a | 13549 | |
c906108c SS |
13550 | @cindex patching binaries |
13551 | @cindex writing into executables | |
c906108c | 13552 | @cindex writing into corefiles |
c906108c | 13553 | |
7a292a7a SS |
13554 | By default, @value{GDBN} opens the file containing your program's |
13555 | executable code (or the corefile) read-only. This prevents accidental | |
13556 | alterations to machine code; but it also prevents you from intentionally | |
13557 | patching your program's binary. | |
c906108c SS |
13558 | |
13559 | If you'd like to be able to patch the binary, you can specify that | |
13560 | explicitly with the @code{set write} command. For example, you might | |
13561 | want to turn on internal debugging flags, or even to make emergency | |
13562 | repairs. | |
13563 | ||
13564 | @table @code | |
13565 | @kindex set write | |
13566 | @item set write on | |
13567 | @itemx set write off | |
7a292a7a | 13568 | If you specify @samp{set write on}, @value{GDBN} opens executable and |
20924a55 | 13569 | core files for both reading and writing; if you specify @kbd{set write |
c906108c SS |
13570 | off} (the default), @value{GDBN} opens them read-only. |
13571 | ||
13572 | If you have already loaded a file, you must load it again (using the | |
7a292a7a SS |
13573 | @code{exec-file} or @code{core-file} command) after changing @code{set |
13574 | write}, for your new setting to take effect. | |
c906108c SS |
13575 | |
13576 | @item show write | |
13577 | @kindex show write | |
7a292a7a SS |
13578 | Display whether executable files and core files are opened for writing |
13579 | as well as reading. | |
c906108c SS |
13580 | @end table |
13581 | ||
6d2ebf8b | 13582 | @node GDB Files |
c906108c SS |
13583 | @chapter @value{GDBN} Files |
13584 | ||
7a292a7a SS |
13585 | @value{GDBN} needs to know the file name of the program to be debugged, |
13586 | both in order to read its symbol table and in order to start your | |
13587 | program. To debug a core dump of a previous run, you must also tell | |
13588 | @value{GDBN} the name of the core dump file. | |
c906108c SS |
13589 | |
13590 | @menu | |
13591 | * Files:: Commands to specify files | |
5b5d99cf | 13592 | * Separate Debug Files:: Debugging information in separate files |
c906108c | 13593 | * Symbol Errors:: Errors reading symbol files |
b14b1491 | 13594 | * Data Files:: GDB data files |
c906108c SS |
13595 | @end menu |
13596 | ||
6d2ebf8b | 13597 | @node Files |
79a6e687 | 13598 | @section Commands to Specify Files |
c906108c | 13599 | |
7a292a7a | 13600 | @cindex symbol table |
c906108c | 13601 | @cindex core dump file |
7a292a7a SS |
13602 | |
13603 | You may want to specify executable and core dump file names. The usual | |
13604 | way to do this is at start-up time, using the arguments to | |
13605 | @value{GDBN}'s start-up commands (@pxref{Invocation, , Getting In and | |
13606 | Out of @value{GDBN}}). | |
c906108c SS |
13607 | |
13608 | Occasionally it is necessary to change to a different file during a | |
397ca115 EZ |
13609 | @value{GDBN} session. Or you may run @value{GDBN} and forget to |
13610 | specify a file you want to use. Or you are debugging a remote target | |
79a6e687 BW |
13611 | via @code{gdbserver} (@pxref{Server, file, Using the @code{gdbserver} |
13612 | Program}). In these situations the @value{GDBN} commands to specify | |
0869d01b | 13613 | new files are useful. |
c906108c SS |
13614 | |
13615 | @table @code | |
13616 | @cindex executable file | |
13617 | @kindex file | |
13618 | @item file @var{filename} | |
13619 | Use @var{filename} as the program to be debugged. It is read for its | |
13620 | symbols and for the contents of pure memory. It is also the program | |
13621 | executed when you use the @code{run} command. If you do not specify a | |
5d161b24 DB |
13622 | directory and the file is not found in the @value{GDBN} working directory, |
13623 | @value{GDBN} uses the environment variable @code{PATH} as a list of | |
13624 | directories to search, just as the shell does when looking for a program | |
13625 | to run. You can change the value of this variable, for both @value{GDBN} | |
c906108c SS |
13626 | and your program, using the @code{path} command. |
13627 | ||
fc8be69e EZ |
13628 | @cindex unlinked object files |
13629 | @cindex patching object files | |
13630 | You can load unlinked object @file{.o} files into @value{GDBN} using | |
13631 | the @code{file} command. You will not be able to ``run'' an object | |
13632 | file, but you can disassemble functions and inspect variables. Also, | |
13633 | if the underlying BFD functionality supports it, you could use | |
13634 | @kbd{gdb -write} to patch object files using this technique. Note | |
13635 | that @value{GDBN} can neither interpret nor modify relocations in this | |
13636 | case, so branches and some initialized variables will appear to go to | |
13637 | the wrong place. But this feature is still handy from time to time. | |
13638 | ||
c906108c SS |
13639 | @item file |
13640 | @code{file} with no argument makes @value{GDBN} discard any information it | |
13641 | has on both executable file and the symbol table. | |
13642 | ||
13643 | @kindex exec-file | |
13644 | @item exec-file @r{[} @var{filename} @r{]} | |
13645 | Specify that the program to be run (but not the symbol table) is found | |
13646 | in @var{filename}. @value{GDBN} searches the environment variable @code{PATH} | |
13647 | if necessary to locate your program. Omitting @var{filename} means to | |
13648 | discard information on the executable file. | |
13649 | ||
13650 | @kindex symbol-file | |
13651 | @item symbol-file @r{[} @var{filename} @r{]} | |
13652 | Read symbol table information from file @var{filename}. @code{PATH} is | |
13653 | searched when necessary. Use the @code{file} command to get both symbol | |
13654 | table and program to run from the same file. | |
13655 | ||
13656 | @code{symbol-file} with no argument clears out @value{GDBN} information on your | |
13657 | program's symbol table. | |
13658 | ||
ae5a43e0 DJ |
13659 | The @code{symbol-file} command causes @value{GDBN} to forget the contents of |
13660 | some breakpoints and auto-display expressions. This is because they may | |
13661 | contain pointers to the internal data recording symbols and data types, | |
13662 | which are part of the old symbol table data being discarded inside | |
13663 | @value{GDBN}. | |
c906108c SS |
13664 | |
13665 | @code{symbol-file} does not repeat if you press @key{RET} again after | |
13666 | executing it once. | |
13667 | ||
13668 | When @value{GDBN} is configured for a particular environment, it | |
13669 | understands debugging information in whatever format is the standard | |
13670 | generated for that environment; you may use either a @sc{gnu} compiler, or | |
13671 | other compilers that adhere to the local conventions. | |
c906108c | 13672 | Best results are usually obtained from @sc{gnu} compilers; for example, |
e22ea452 | 13673 | using @code{@value{NGCC}} you can generate debugging information for |
c906108c | 13674 | optimized code. |
c906108c SS |
13675 | |
13676 | For most kinds of object files, with the exception of old SVR3 systems | |
13677 | using COFF, the @code{symbol-file} command does not normally read the | |
13678 | symbol table in full right away. Instead, it scans the symbol table | |
13679 | quickly to find which source files and which symbols are present. The | |
13680 | details are read later, one source file at a time, as they are needed. | |
13681 | ||
13682 | The purpose of this two-stage reading strategy is to make @value{GDBN} | |
13683 | start up faster. For the most part, it is invisible except for | |
13684 | occasional pauses while the symbol table details for a particular source | |
13685 | file are being read. (The @code{set verbose} command can turn these | |
13686 | pauses into messages if desired. @xref{Messages/Warnings, ,Optional | |
79a6e687 | 13687 | Warnings and Messages}.) |
c906108c | 13688 | |
c906108c SS |
13689 | We have not implemented the two-stage strategy for COFF yet. When the |
13690 | symbol table is stored in COFF format, @code{symbol-file} reads the | |
13691 | symbol table data in full right away. Note that ``stabs-in-COFF'' | |
13692 | still does the two-stage strategy, since the debug info is actually | |
13693 | in stabs format. | |
13694 | ||
13695 | @kindex readnow | |
13696 | @cindex reading symbols immediately | |
13697 | @cindex symbols, reading immediately | |
a94ab193 EZ |
13698 | @item symbol-file @var{filename} @r{[} -readnow @r{]} |
13699 | @itemx file @var{filename} @r{[} -readnow @r{]} | |
c906108c SS |
13700 | You can override the @value{GDBN} two-stage strategy for reading symbol |
13701 | tables by using the @samp{-readnow} option with any of the commands that | |
13702 | load symbol table information, if you want to be sure @value{GDBN} has the | |
5d161b24 | 13703 | entire symbol table available. |
c906108c | 13704 | |
c906108c SS |
13705 | @c FIXME: for now no mention of directories, since this seems to be in |
13706 | @c flux. 13mar1992 status is that in theory GDB would look either in | |
13707 | @c current dir or in same dir as myprog; but issues like competing | |
13708 | @c GDB's, or clutter in system dirs, mean that in practice right now | |
13709 | @c only current dir is used. FFish says maybe a special GDB hierarchy | |
13710 | @c (eg rooted in val of env var GDBSYMS) could exist for mappable symbol | |
13711 | @c files. | |
13712 | ||
c906108c | 13713 | @kindex core-file |
09d4efe1 | 13714 | @item core-file @r{[}@var{filename}@r{]} |
4644b6e3 | 13715 | @itemx core |
c906108c SS |
13716 | Specify the whereabouts of a core dump file to be used as the ``contents |
13717 | of memory''. Traditionally, core files contain only some parts of the | |
13718 | address space of the process that generated them; @value{GDBN} can access the | |
13719 | executable file itself for other parts. | |
13720 | ||
13721 | @code{core-file} with no argument specifies that no core file is | |
13722 | to be used. | |
13723 | ||
13724 | Note that the core file is ignored when your program is actually running | |
7a292a7a SS |
13725 | under @value{GDBN}. So, if you have been running your program and you |
13726 | wish to debug a core file instead, you must kill the subprocess in which | |
13727 | the program is running. To do this, use the @code{kill} command | |
79a6e687 | 13728 | (@pxref{Kill Process, ,Killing the Child Process}). |
c906108c | 13729 | |
c906108c SS |
13730 | @kindex add-symbol-file |
13731 | @cindex dynamic linking | |
13732 | @item add-symbol-file @var{filename} @var{address} | |
a94ab193 | 13733 | @itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]} |
17d9d558 | 13734 | @itemx add-symbol-file @var{filename} @r{-s}@var{section} @var{address} @dots{} |
96a2c332 SS |
13735 | The @code{add-symbol-file} command reads additional symbol table |
13736 | information from the file @var{filename}. You would use this command | |
13737 | when @var{filename} has been dynamically loaded (by some other means) | |
13738 | into the program that is running. @var{address} should be the memory | |
13739 | address at which the file has been loaded; @value{GDBN} cannot figure | |
d167840f EZ |
13740 | this out for itself. You can additionally specify an arbitrary number |
13741 | of @samp{@r{-s}@var{section} @var{address}} pairs, to give an explicit | |
13742 | section name and base address for that section. You can specify any | |
13743 | @var{address} as an expression. | |
c906108c SS |
13744 | |
13745 | The symbol table of the file @var{filename} is added to the symbol table | |
13746 | originally read with the @code{symbol-file} command. You can use the | |
96a2c332 SS |
13747 | @code{add-symbol-file} command any number of times; the new symbol data |
13748 | thus read keeps adding to the old. To discard all old symbol data | |
13749 | instead, use the @code{symbol-file} command without any arguments. | |
c906108c | 13750 | |
17d9d558 JB |
13751 | @cindex relocatable object files, reading symbols from |
13752 | @cindex object files, relocatable, reading symbols from | |
13753 | @cindex reading symbols from relocatable object files | |
13754 | @cindex symbols, reading from relocatable object files | |
13755 | @cindex @file{.o} files, reading symbols from | |
13756 | Although @var{filename} is typically a shared library file, an | |
13757 | executable file, or some other object file which has been fully | |
13758 | relocated for loading into a process, you can also load symbolic | |
13759 | information from relocatable @file{.o} files, as long as: | |
13760 | ||
13761 | @itemize @bullet | |
13762 | @item | |
13763 | the file's symbolic information refers only to linker symbols defined in | |
13764 | that file, not to symbols defined by other object files, | |
13765 | @item | |
13766 | every section the file's symbolic information refers to has actually | |
13767 | been loaded into the inferior, as it appears in the file, and | |
13768 | @item | |
13769 | you can determine the address at which every section was loaded, and | |
13770 | provide these to the @code{add-symbol-file} command. | |
13771 | @end itemize | |
13772 | ||
13773 | @noindent | |
13774 | Some embedded operating systems, like Sun Chorus and VxWorks, can load | |
13775 | relocatable files into an already running program; such systems | |
13776 | typically make the requirements above easy to meet. However, it's | |
13777 | important to recognize that many native systems use complex link | |
49efadf5 | 13778 | procedures (@code{.linkonce} section factoring and C@t{++} constructor table |
17d9d558 JB |
13779 | assembly, for example) that make the requirements difficult to meet. In |
13780 | general, one cannot assume that using @code{add-symbol-file} to read a | |
13781 | relocatable object file's symbolic information will have the same effect | |
13782 | as linking the relocatable object file into the program in the normal | |
13783 | way. | |
13784 | ||
c906108c SS |
13785 | @code{add-symbol-file} does not repeat if you press @key{RET} after using it. |
13786 | ||
c45da7e6 EZ |
13787 | @kindex add-symbol-file-from-memory |
13788 | @cindex @code{syscall DSO} | |
13789 | @cindex load symbols from memory | |
13790 | @item add-symbol-file-from-memory @var{address} | |
13791 | Load symbols from the given @var{address} in a dynamically loaded | |
13792 | object file whose image is mapped directly into the inferior's memory. | |
13793 | For example, the Linux kernel maps a @code{syscall DSO} into each | |
13794 | process's address space; this DSO provides kernel-specific code for | |
13795 | some system calls. The argument can be any expression whose | |
13796 | evaluation yields the address of the file's shared object file header. | |
13797 | For this command to work, you must have used @code{symbol-file} or | |
13798 | @code{exec-file} commands in advance. | |
13799 | ||
09d4efe1 EZ |
13800 | @kindex add-shared-symbol-files |
13801 | @kindex assf | |
13802 | @item add-shared-symbol-files @var{library-file} | |
13803 | @itemx assf @var{library-file} | |
13804 | The @code{add-shared-symbol-files} command can currently be used only | |
13805 | in the Cygwin build of @value{GDBN} on MS-Windows OS, where it is an | |
13806 | alias for the @code{dll-symbols} command (@pxref{Cygwin Native}). | |
13807 | @value{GDBN} automatically looks for shared libraries, however if | |
13808 | @value{GDBN} does not find yours, you can invoke | |
13809 | @code{add-shared-symbol-files}. It takes one argument: the shared | |
13810 | library's file name. @code{assf} is a shorthand alias for | |
13811 | @code{add-shared-symbol-files}. | |
c906108c | 13812 | |
c906108c | 13813 | @kindex section |
09d4efe1 EZ |
13814 | @item section @var{section} @var{addr} |
13815 | The @code{section} command changes the base address of the named | |
13816 | @var{section} of the exec file to @var{addr}. This can be used if the | |
13817 | exec file does not contain section addresses, (such as in the | |
13818 | @code{a.out} format), or when the addresses specified in the file | |
13819 | itself are wrong. Each section must be changed separately. The | |
13820 | @code{info files} command, described below, lists all the sections and | |
13821 | their addresses. | |
c906108c SS |
13822 | |
13823 | @kindex info files | |
13824 | @kindex info target | |
13825 | @item info files | |
13826 | @itemx info target | |
7a292a7a SS |
13827 | @code{info files} and @code{info target} are synonymous; both print the |
13828 | current target (@pxref{Targets, ,Specifying a Debugging Target}), | |
13829 | including the names of the executable and core dump files currently in | |
13830 | use by @value{GDBN}, and the files from which symbols were loaded. The | |
13831 | command @code{help target} lists all possible targets rather than | |
13832 | current ones. | |
13833 | ||
fe95c787 MS |
13834 | @kindex maint info sections |
13835 | @item maint info sections | |
13836 | Another command that can give you extra information about program sections | |
13837 | is @code{maint info sections}. In addition to the section information | |
13838 | displayed by @code{info files}, this command displays the flags and file | |
13839 | offset of each section in the executable and core dump files. In addition, | |
13840 | @code{maint info sections} provides the following command options (which | |
13841 | may be arbitrarily combined): | |
13842 | ||
13843 | @table @code | |
13844 | @item ALLOBJ | |
13845 | Display sections for all loaded object files, including shared libraries. | |
13846 | @item @var{sections} | |
6600abed | 13847 | Display info only for named @var{sections}. |
fe95c787 MS |
13848 | @item @var{section-flags} |
13849 | Display info only for sections for which @var{section-flags} are true. | |
13850 | The section flags that @value{GDBN} currently knows about are: | |
13851 | @table @code | |
13852 | @item ALLOC | |
13853 | Section will have space allocated in the process when loaded. | |
13854 | Set for all sections except those containing debug information. | |
13855 | @item LOAD | |
13856 | Section will be loaded from the file into the child process memory. | |
13857 | Set for pre-initialized code and data, clear for @code{.bss} sections. | |
13858 | @item RELOC | |
13859 | Section needs to be relocated before loading. | |
13860 | @item READONLY | |
13861 | Section cannot be modified by the child process. | |
13862 | @item CODE | |
13863 | Section contains executable code only. | |
6600abed | 13864 | @item DATA |
fe95c787 MS |
13865 | Section contains data only (no executable code). |
13866 | @item ROM | |
13867 | Section will reside in ROM. | |
13868 | @item CONSTRUCTOR | |
13869 | Section contains data for constructor/destructor lists. | |
13870 | @item HAS_CONTENTS | |
13871 | Section is not empty. | |
13872 | @item NEVER_LOAD | |
13873 | An instruction to the linker to not output the section. | |
13874 | @item COFF_SHARED_LIBRARY | |
13875 | A notification to the linker that the section contains | |
13876 | COFF shared library information. | |
13877 | @item IS_COMMON | |
13878 | Section contains common symbols. | |
13879 | @end table | |
13880 | @end table | |
6763aef9 | 13881 | @kindex set trust-readonly-sections |
9c16f35a | 13882 | @cindex read-only sections |
6763aef9 MS |
13883 | @item set trust-readonly-sections on |
13884 | Tell @value{GDBN} that readonly sections in your object file | |
6ca652b0 | 13885 | really are read-only (i.e.@: that their contents will not change). |
6763aef9 MS |
13886 | In that case, @value{GDBN} can fetch values from these sections |
13887 | out of the object file, rather than from the target program. | |
13888 | For some targets (notably embedded ones), this can be a significant | |
13889 | enhancement to debugging performance. | |
13890 | ||
13891 | The default is off. | |
13892 | ||
13893 | @item set trust-readonly-sections off | |
15110bc3 | 13894 | Tell @value{GDBN} not to trust readonly sections. This means that |
6763aef9 MS |
13895 | the contents of the section might change while the program is running, |
13896 | and must therefore be fetched from the target when needed. | |
9c16f35a EZ |
13897 | |
13898 | @item show trust-readonly-sections | |
13899 | Show the current setting of trusting readonly sections. | |
c906108c SS |
13900 | @end table |
13901 | ||
13902 | All file-specifying commands allow both absolute and relative file names | |
13903 | as arguments. @value{GDBN} always converts the file name to an absolute file | |
13904 | name and remembers it that way. | |
13905 | ||
c906108c | 13906 | @cindex shared libraries |
9cceb671 DJ |
13907 | @anchor{Shared Libraries} |
13908 | @value{GDBN} supports @sc{gnu}/Linux, MS-Windows, HP-UX, SunOS, SVr4, Irix, | |
9c16f35a | 13909 | and IBM RS/6000 AIX shared libraries. |
53a5351d | 13910 | |
9cceb671 DJ |
13911 | On MS-Windows @value{GDBN} must be linked with the Expat library to support |
13912 | shared libraries. @xref{Expat}. | |
13913 | ||
c906108c SS |
13914 | @value{GDBN} automatically loads symbol definitions from shared libraries |
13915 | when you use the @code{run} command, or when you examine a core file. | |
13916 | (Before you issue the @code{run} command, @value{GDBN} does not understand | |
13917 | references to a function in a shared library, however---unless you are | |
13918 | debugging a core file). | |
53a5351d JM |
13919 | |
13920 | On HP-UX, if the program loads a library explicitly, @value{GDBN} | |
13921 | automatically loads the symbols at the time of the @code{shl_load} call. | |
13922 | ||
c906108c SS |
13923 | @c FIXME: some @value{GDBN} release may permit some refs to undef |
13924 | @c FIXME...symbols---eg in a break cmd---assuming they are from a shared | |
13925 | @c FIXME...lib; check this from time to time when updating manual | |
13926 | ||
b7209cb4 FF |
13927 | There are times, however, when you may wish to not automatically load |
13928 | symbol definitions from shared libraries, such as when they are | |
13929 | particularly large or there are many of them. | |
13930 | ||
13931 | To control the automatic loading of shared library symbols, use the | |
13932 | commands: | |
13933 | ||
13934 | @table @code | |
13935 | @kindex set auto-solib-add | |
13936 | @item set auto-solib-add @var{mode} | |
13937 | If @var{mode} is @code{on}, symbols from all shared object libraries | |
13938 | will be loaded automatically when the inferior begins execution, you | |
13939 | attach to an independently started inferior, or when the dynamic linker | |
13940 | informs @value{GDBN} that a new library has been loaded. If @var{mode} | |
13941 | is @code{off}, symbols must be loaded manually, using the | |
13942 | @code{sharedlibrary} command. The default value is @code{on}. | |
13943 | ||
dcaf7c2c EZ |
13944 | @cindex memory used for symbol tables |
13945 | If your program uses lots of shared libraries with debug info that | |
13946 | takes large amounts of memory, you can decrease the @value{GDBN} | |
13947 | memory footprint by preventing it from automatically loading the | |
13948 | symbols from shared libraries. To that end, type @kbd{set | |
13949 | auto-solib-add off} before running the inferior, then load each | |
13950 | library whose debug symbols you do need with @kbd{sharedlibrary | |
d3e8051b | 13951 | @var{regexp}}, where @var{regexp} is a regular expression that matches |
dcaf7c2c EZ |
13952 | the libraries whose symbols you want to be loaded. |
13953 | ||
b7209cb4 FF |
13954 | @kindex show auto-solib-add |
13955 | @item show auto-solib-add | |
13956 | Display the current autoloading mode. | |
13957 | @end table | |
13958 | ||
c45da7e6 | 13959 | @cindex load shared library |
b7209cb4 FF |
13960 | To explicitly load shared library symbols, use the @code{sharedlibrary} |
13961 | command: | |
13962 | ||
c906108c SS |
13963 | @table @code |
13964 | @kindex info sharedlibrary | |
13965 | @kindex info share | |
55333a84 DE |
13966 | @item info share @var{regex} |
13967 | @itemx info sharedlibrary @var{regex} | |
13968 | Print the names of the shared libraries which are currently loaded | |
13969 | that match @var{regex}. If @var{regex} is omitted then print | |
13970 | all shared libraries that are loaded. | |
c906108c SS |
13971 | |
13972 | @kindex sharedlibrary | |
13973 | @kindex share | |
13974 | @item sharedlibrary @var{regex} | |
13975 | @itemx share @var{regex} | |
c906108c SS |
13976 | Load shared object library symbols for files matching a |
13977 | Unix regular expression. | |
13978 | As with files loaded automatically, it only loads shared libraries | |
13979 | required by your program for a core file or after typing @code{run}. If | |
13980 | @var{regex} is omitted all shared libraries required by your program are | |
13981 | loaded. | |
c45da7e6 EZ |
13982 | |
13983 | @item nosharedlibrary | |
13984 | @kindex nosharedlibrary | |
13985 | @cindex unload symbols from shared libraries | |
13986 | Unload all shared object library symbols. This discards all symbols | |
13987 | that have been loaded from all shared libraries. Symbols from shared | |
13988 | libraries that were loaded by explicit user requests are not | |
13989 | discarded. | |
c906108c SS |
13990 | @end table |
13991 | ||
721c2651 EZ |
13992 | Sometimes you may wish that @value{GDBN} stops and gives you control |
13993 | when any of shared library events happen. Use the @code{set | |
13994 | stop-on-solib-events} command for this: | |
13995 | ||
13996 | @table @code | |
13997 | @item set stop-on-solib-events | |
13998 | @kindex set stop-on-solib-events | |
13999 | This command controls whether @value{GDBN} should give you control | |
14000 | when the dynamic linker notifies it about some shared library event. | |
14001 | The most common event of interest is loading or unloading of a new | |
14002 | shared library. | |
14003 | ||
14004 | @item show stop-on-solib-events | |
14005 | @kindex show stop-on-solib-events | |
14006 | Show whether @value{GDBN} stops and gives you control when shared | |
14007 | library events happen. | |
14008 | @end table | |
14009 | ||
f5ebfba0 | 14010 | Shared libraries are also supported in many cross or remote debugging |
f1838a98 UW |
14011 | configurations. @value{GDBN} needs to have access to the target's libraries; |
14012 | this can be accomplished either by providing copies of the libraries | |
14013 | on the host system, or by asking @value{GDBN} to automatically retrieve the | |
14014 | libraries from the target. If copies of the target libraries are | |
14015 | provided, they need to be the same as the target libraries, although the | |
f5ebfba0 DJ |
14016 | copies on the target can be stripped as long as the copies on the host are |
14017 | not. | |
14018 | ||
59b7b46f EZ |
14019 | @cindex where to look for shared libraries |
14020 | For remote debugging, you need to tell @value{GDBN} where the target | |
14021 | libraries are, so that it can load the correct copies---otherwise, it | |
14022 | may try to load the host's libraries. @value{GDBN} has two variables | |
14023 | to specify the search directories for target libraries. | |
f5ebfba0 DJ |
14024 | |
14025 | @table @code | |
59b7b46f | 14026 | @cindex prefix for shared library file names |
f822c95b | 14027 | @cindex system root, alternate |
f5ebfba0 | 14028 | @kindex set solib-absolute-prefix |
f822c95b DJ |
14029 | @kindex set sysroot |
14030 | @item set sysroot @var{path} | |
14031 | Use @var{path} as the system root for the program being debugged. Any | |
14032 | absolute shared library paths will be prefixed with @var{path}; many | |
14033 | runtime loaders store the absolute paths to the shared library in the | |
14034 | target program's memory. If you use @code{set sysroot} to find shared | |
14035 | libraries, they need to be laid out in the same way that they are on | |
14036 | the target, with e.g.@: a @file{/lib} and @file{/usr/lib} hierarchy | |
14037 | under @var{path}. | |
14038 | ||
f1838a98 UW |
14039 | If @var{path} starts with the sequence @file{remote:}, @value{GDBN} will |
14040 | retrieve the target libraries from the remote system. This is only | |
14041 | supported when using a remote target that supports the @code{remote get} | |
14042 | command (@pxref{File Transfer,,Sending files to a remote system}). | |
14043 | The part of @var{path} following the initial @file{remote:} | |
14044 | (if present) is used as system root prefix on the remote file system. | |
14045 | @footnote{If you want to specify a local system root using a directory | |
14046 | that happens to be named @file{remote:}, you need to use some equivalent | |
14047 | variant of the name like @file{./remote:}.} | |
14048 | ||
f822c95b DJ |
14049 | The @code{set solib-absolute-prefix} command is an alias for @code{set |
14050 | sysroot}. | |
14051 | ||
14052 | @cindex default system root | |
59b7b46f | 14053 | @cindex @samp{--with-sysroot} |
f822c95b DJ |
14054 | You can set the default system root by using the configure-time |
14055 | @samp{--with-sysroot} option. If the system root is inside | |
14056 | @value{GDBN}'s configured binary prefix (set with @samp{--prefix} or | |
14057 | @samp{--exec-prefix}), then the default system root will be updated | |
14058 | automatically if the installed @value{GDBN} is moved to a new | |
14059 | location. | |
14060 | ||
14061 | @kindex show sysroot | |
14062 | @item show sysroot | |
f5ebfba0 DJ |
14063 | Display the current shared library prefix. |
14064 | ||
14065 | @kindex set solib-search-path | |
14066 | @item set solib-search-path @var{path} | |
f822c95b DJ |
14067 | If this variable is set, @var{path} is a colon-separated list of |
14068 | directories to search for shared libraries. @samp{solib-search-path} | |
14069 | is used after @samp{sysroot} fails to locate the library, or if the | |
14070 | path to the library is relative instead of absolute. If you want to | |
14071 | use @samp{solib-search-path} instead of @samp{sysroot}, be sure to set | |
d3e8051b | 14072 | @samp{sysroot} to a nonexistent directory to prevent @value{GDBN} from |
f822c95b | 14073 | finding your host's libraries. @samp{sysroot} is preferred; setting |
d3e8051b | 14074 | it to a nonexistent directory may interfere with automatic loading |
f822c95b | 14075 | of shared library symbols. |
f5ebfba0 DJ |
14076 | |
14077 | @kindex show solib-search-path | |
14078 | @item show solib-search-path | |
14079 | Display the current shared library search path. | |
14080 | @end table | |
14081 | ||
5b5d99cf JB |
14082 | |
14083 | @node Separate Debug Files | |
14084 | @section Debugging Information in Separate Files | |
14085 | @cindex separate debugging information files | |
14086 | @cindex debugging information in separate files | |
14087 | @cindex @file{.debug} subdirectories | |
14088 | @cindex debugging information directory, global | |
14089 | @cindex global debugging information directory | |
c7e83d54 EZ |
14090 | @cindex build ID, and separate debugging files |
14091 | @cindex @file{.build-id} directory | |
5b5d99cf JB |
14092 | |
14093 | @value{GDBN} allows you to put a program's debugging information in a | |
14094 | file separate from the executable itself, in a way that allows | |
14095 | @value{GDBN} to find and load the debugging information automatically. | |
c7e83d54 EZ |
14096 | Since debugging information can be very large---sometimes larger |
14097 | than the executable code itself---some systems distribute debugging | |
5b5d99cf JB |
14098 | information for their executables in separate files, which users can |
14099 | install only when they need to debug a problem. | |
14100 | ||
c7e83d54 EZ |
14101 | @value{GDBN} supports two ways of specifying the separate debug info |
14102 | file: | |
5b5d99cf JB |
14103 | |
14104 | @itemize @bullet | |
14105 | @item | |
c7e83d54 EZ |
14106 | The executable contains a @dfn{debug link} that specifies the name of |
14107 | the separate debug info file. The separate debug file's name is | |
14108 | usually @file{@var{executable}.debug}, where @var{executable} is the | |
14109 | name of the corresponding executable file without leading directories | |
14110 | (e.g., @file{ls.debug} for @file{/usr/bin/ls}). In addition, the | |
99e008fe EZ |
14111 | debug link specifies a 32-bit @dfn{Cyclic Redundancy Check} (CRC) |
14112 | checksum for the debug file, which @value{GDBN} uses to validate that | |
14113 | the executable and the debug file came from the same build. | |
c7e83d54 EZ |
14114 | |
14115 | @item | |
7e27a47a | 14116 | The executable contains a @dfn{build ID}, a unique bit string that is |
c7e83d54 | 14117 | also present in the corresponding debug info file. (This is supported |
7e27a47a EZ |
14118 | only on some operating systems, notably those which use the ELF format |
14119 | for binary files and the @sc{gnu} Binutils.) For more details about | |
14120 | this feature, see the description of the @option{--build-id} | |
14121 | command-line option in @ref{Options, , Command Line Options, ld.info, | |
14122 | The GNU Linker}. The debug info file's name is not specified | |
14123 | explicitly by the build ID, but can be computed from the build ID, see | |
14124 | below. | |
d3750b24 JK |
14125 | @end itemize |
14126 | ||
c7e83d54 EZ |
14127 | Depending on the way the debug info file is specified, @value{GDBN} |
14128 | uses two different methods of looking for the debug file: | |
d3750b24 JK |
14129 | |
14130 | @itemize @bullet | |
14131 | @item | |
c7e83d54 EZ |
14132 | For the ``debug link'' method, @value{GDBN} looks up the named file in |
14133 | the directory of the executable file, then in a subdirectory of that | |
14134 | directory named @file{.debug}, and finally under the global debug | |
14135 | directory, in a subdirectory whose name is identical to the leading | |
14136 | directories of the executable's absolute file name. | |
14137 | ||
14138 | @item | |
83f83d7f | 14139 | For the ``build ID'' method, @value{GDBN} looks in the |
c7e83d54 EZ |
14140 | @file{.build-id} subdirectory of the global debug directory for a file |
14141 | named @file{@var{nn}/@var{nnnnnnnn}.debug}, where @var{nn} are the | |
7e27a47a EZ |
14142 | first 2 hex characters of the build ID bit string, and @var{nnnnnnnn} |
14143 | are the rest of the bit string. (Real build ID strings are 32 or more | |
14144 | hex characters, not 10.) | |
c7e83d54 EZ |
14145 | @end itemize |
14146 | ||
14147 | So, for example, suppose you ask @value{GDBN} to debug | |
7e27a47a EZ |
14148 | @file{/usr/bin/ls}, which has a debug link that specifies the |
14149 | file @file{ls.debug}, and a build ID whose value in hex is | |
c7e83d54 EZ |
14150 | @code{abcdef1234}. If the global debug directory is |
14151 | @file{/usr/lib/debug}, then @value{GDBN} will look for the following | |
14152 | debug information files, in the indicated order: | |
14153 | ||
14154 | @itemize @minus | |
14155 | @item | |
14156 | @file{/usr/lib/debug/.build-id/ab/cdef1234.debug} | |
d3750b24 | 14157 | @item |
c7e83d54 | 14158 | @file{/usr/bin/ls.debug} |
5b5d99cf | 14159 | @item |
c7e83d54 | 14160 | @file{/usr/bin/.debug/ls.debug} |
5b5d99cf | 14161 | @item |
c7e83d54 | 14162 | @file{/usr/lib/debug/usr/bin/ls.debug}. |
5b5d99cf | 14163 | @end itemize |
5b5d99cf JB |
14164 | |
14165 | You can set the global debugging info directory's name, and view the | |
14166 | name @value{GDBN} is currently using. | |
14167 | ||
14168 | @table @code | |
14169 | ||
14170 | @kindex set debug-file-directory | |
24ddea62 JK |
14171 | @item set debug-file-directory @var{directories} |
14172 | Set the directories which @value{GDBN} searches for separate debugging | |
14173 | information files to @var{directory}. Multiple directory components can be set | |
14174 | concatenating them by a directory separator. | |
5b5d99cf JB |
14175 | |
14176 | @kindex show debug-file-directory | |
14177 | @item show debug-file-directory | |
24ddea62 | 14178 | Show the directories @value{GDBN} searches for separate debugging |
5b5d99cf JB |
14179 | information files. |
14180 | ||
14181 | @end table | |
14182 | ||
14183 | @cindex @code{.gnu_debuglink} sections | |
c7e83d54 | 14184 | @cindex debug link sections |
5b5d99cf JB |
14185 | A debug link is a special section of the executable file named |
14186 | @code{.gnu_debuglink}. The section must contain: | |
14187 | ||
14188 | @itemize | |
14189 | @item | |
14190 | A filename, with any leading directory components removed, followed by | |
14191 | a zero byte, | |
14192 | @item | |
14193 | zero to three bytes of padding, as needed to reach the next four-byte | |
14194 | boundary within the section, and | |
14195 | @item | |
14196 | a four-byte CRC checksum, stored in the same endianness used for the | |
14197 | executable file itself. The checksum is computed on the debugging | |
14198 | information file's full contents by the function given below, passing | |
14199 | zero as the @var{crc} argument. | |
14200 | @end itemize | |
14201 | ||
14202 | Any executable file format can carry a debug link, as long as it can | |
14203 | contain a section named @code{.gnu_debuglink} with the contents | |
14204 | described above. | |
14205 | ||
d3750b24 | 14206 | @cindex @code{.note.gnu.build-id} sections |
c7e83d54 | 14207 | @cindex build ID sections |
7e27a47a EZ |
14208 | The build ID is a special section in the executable file (and in other |
14209 | ELF binary files that @value{GDBN} may consider). This section is | |
14210 | often named @code{.note.gnu.build-id}, but that name is not mandatory. | |
14211 | It contains unique identification for the built files---the ID remains | |
14212 | the same across multiple builds of the same build tree. The default | |
14213 | algorithm SHA1 produces 160 bits (40 hexadecimal characters) of the | |
14214 | content for the build ID string. The same section with an identical | |
14215 | value is present in the original built binary with symbols, in its | |
14216 | stripped variant, and in the separate debugging information file. | |
d3750b24 | 14217 | |
5b5d99cf JB |
14218 | The debugging information file itself should be an ordinary |
14219 | executable, containing a full set of linker symbols, sections, and | |
14220 | debugging information. The sections of the debugging information file | |
c7e83d54 EZ |
14221 | should have the same names, addresses, and sizes as the original file, |
14222 | but they need not contain any data---much like a @code{.bss} section | |
5b5d99cf JB |
14223 | in an ordinary executable. |
14224 | ||
7e27a47a | 14225 | The @sc{gnu} binary utilities (Binutils) package includes the |
c7e83d54 EZ |
14226 | @samp{objcopy} utility that can produce |
14227 | the separated executable / debugging information file pairs using the | |
14228 | following commands: | |
14229 | ||
14230 | @smallexample | |
14231 | @kbd{objcopy --only-keep-debug foo foo.debug} | |
14232 | @kbd{strip -g foo} | |
c7e83d54 EZ |
14233 | @end smallexample |
14234 | ||
14235 | @noindent | |
14236 | These commands remove the debugging | |
83f83d7f JK |
14237 | information from the executable file @file{foo} and place it in the file |
14238 | @file{foo.debug}. You can use the first, second or both methods to link the | |
14239 | two files: | |
14240 | ||
14241 | @itemize @bullet | |
14242 | @item | |
14243 | The debug link method needs the following additional command to also leave | |
14244 | behind a debug link in @file{foo}: | |
14245 | ||
14246 | @smallexample | |
14247 | @kbd{objcopy --add-gnu-debuglink=foo.debug foo} | |
14248 | @end smallexample | |
14249 | ||
14250 | Ulrich Drepper's @file{elfutils} package, starting with version 0.53, contains | |
d3750b24 | 14251 | a version of the @code{strip} command such that the command @kbd{strip foo -f |
83f83d7f JK |
14252 | foo.debug} has the same functionality as the two @code{objcopy} commands and |
14253 | the @code{ln -s} command above, together. | |
14254 | ||
14255 | @item | |
14256 | Build ID gets embedded into the main executable using @code{ld --build-id} or | |
14257 | the @value{NGCC} counterpart @code{gcc -Wl,--build-id}. Build ID support plus | |
14258 | compatibility fixes for debug files separation are present in @sc{gnu} binary | |
7e27a47a | 14259 | utilities (Binutils) package since version 2.18. |
83f83d7f JK |
14260 | @end itemize |
14261 | ||
14262 | @noindent | |
d3750b24 | 14263 | |
99e008fe EZ |
14264 | @cindex CRC algorithm definition |
14265 | The CRC used in @code{.gnu_debuglink} is the CRC-32 defined in | |
14266 | IEEE 802.3 using the polynomial: | |
14267 | ||
14268 | @c TexInfo requires naked braces for multi-digit exponents for Tex | |
14269 | @c output, but this causes HTML output to barf. HTML has to be set using | |
14270 | @c raw commands. So we end up having to specify this equation in 2 | |
14271 | @c different ways! | |
14272 | @ifhtml | |
14273 | @display | |
14274 | @html | |
14275 | <em>x</em><sup>32</sup> + <em>x</em><sup>26</sup> + <em>x</em><sup>23</sup> + <em>x</em><sup>22</sup> + <em>x</em><sup>16</sup> + <em>x</em><sup>12</sup> + <em>x</em><sup>11</sup> | |
14276 | + <em>x</em><sup>10</sup> + <em>x</em><sup>8</sup> + <em>x</em><sup>7</sup> + <em>x</em><sup>5</sup> + <em>x</em><sup>4</sup> + <em>x</em><sup>2</sup> + <em>x</em> + 1 | |
14277 | @end html | |
14278 | @end display | |
14279 | @end ifhtml | |
14280 | @ifnothtml | |
14281 | @display | |
14282 | @math{x^{32} + x^{26} + x^{23} + x^{22} + x^{16} + x^{12} + x^{11}} | |
14283 | @math{+ x^{10} + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1} | |
14284 | @end display | |
14285 | @end ifnothtml | |
14286 | ||
14287 | The function is computed byte at a time, taking the least | |
14288 | significant bit of each byte first. The initial pattern | |
14289 | @code{0xffffffff} is used, to ensure leading zeros affect the CRC and | |
14290 | the final result is inverted to ensure trailing zeros also affect the | |
14291 | CRC. | |
14292 | ||
14293 | @emph{Note:} This is the same CRC polynomial as used in handling the | |
14294 | @dfn{Remote Serial Protocol} @code{qCRC} packet (@pxref{Remote Protocol, | |
14295 | , @value{GDBN} Remote Serial Protocol}). However in the | |
14296 | case of the Remote Serial Protocol, the CRC is computed @emph{most} | |
14297 | significant bit first, and the result is not inverted, so trailing | |
14298 | zeros have no effect on the CRC value. | |
14299 | ||
14300 | To complete the description, we show below the code of the function | |
14301 | which produces the CRC used in @code{.gnu_debuglink}. Inverting the | |
14302 | initially supplied @code{crc} argument means that an initial call to | |
14303 | this function passing in zero will start computing the CRC using | |
14304 | @code{0xffffffff}. | |
5b5d99cf | 14305 | |
4644b6e3 | 14306 | @kindex gnu_debuglink_crc32 |
5b5d99cf JB |
14307 | @smallexample |
14308 | unsigned long | |
14309 | gnu_debuglink_crc32 (unsigned long crc, | |
14310 | unsigned char *buf, size_t len) | |
14311 | @{ | |
14312 | static const unsigned long crc32_table[256] = | |
14313 | @{ | |
14314 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, | |
14315 | 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, | |
14316 | 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, | |
14317 | 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, | |
14318 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, | |
14319 | 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, | |
14320 | 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, | |
14321 | 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, | |
14322 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, | |
14323 | 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, | |
14324 | 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, | |
14325 | 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, | |
14326 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, | |
14327 | 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, | |
14328 | 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, | |
14329 | 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, | |
14330 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, | |
14331 | 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, | |
14332 | 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, | |
14333 | 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, | |
14334 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, | |
14335 | 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, | |
14336 | 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, | |
14337 | 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, | |
14338 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, | |
14339 | 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, | |
14340 | 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, | |
14341 | 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, | |
14342 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, | |
14343 | 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, | |
14344 | 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, | |
14345 | 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, | |
14346 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, | |
14347 | 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, | |
14348 | 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, | |
14349 | 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, | |
14350 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, | |
14351 | 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, | |
14352 | 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, | |
14353 | 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, | |
14354 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, | |
14355 | 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, | |
14356 | 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, | |
14357 | 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, | |
14358 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, | |
14359 | 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, | |
14360 | 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, | |
14361 | 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, | |
14362 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, | |
14363 | 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, | |
14364 | 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, | |
14365 | 0x2d02ef8d | |
14366 | @}; | |
14367 | unsigned char *end; | |
14368 | ||
14369 | crc = ~crc & 0xffffffff; | |
14370 | for (end = buf + len; buf < end; ++buf) | |
14371 | crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8); | |
e7a3abfc | 14372 | return ~crc & 0xffffffff; |
5b5d99cf JB |
14373 | @} |
14374 | @end smallexample | |
14375 | ||
c7e83d54 EZ |
14376 | @noindent |
14377 | This computation does not apply to the ``build ID'' method. | |
14378 | ||
5b5d99cf | 14379 | |
6d2ebf8b | 14380 | @node Symbol Errors |
79a6e687 | 14381 | @section Errors Reading Symbol Files |
c906108c SS |
14382 | |
14383 | While reading a symbol file, @value{GDBN} occasionally encounters problems, | |
14384 | such as symbol types it does not recognize, or known bugs in compiler | |
14385 | output. By default, @value{GDBN} does not notify you of such problems, since | |
14386 | they are relatively common and primarily of interest to people | |
14387 | debugging compilers. If you are interested in seeing information | |
14388 | about ill-constructed symbol tables, you can either ask @value{GDBN} to print | |
14389 | only one message about each such type of problem, no matter how many | |
14390 | times the problem occurs; or you can ask @value{GDBN} to print more messages, | |
14391 | to see how many times the problems occur, with the @code{set | |
79a6e687 BW |
14392 | complaints} command (@pxref{Messages/Warnings, ,Optional Warnings and |
14393 | Messages}). | |
c906108c SS |
14394 | |
14395 | The messages currently printed, and their meanings, include: | |
14396 | ||
14397 | @table @code | |
14398 | @item inner block not inside outer block in @var{symbol} | |
14399 | ||
14400 | The symbol information shows where symbol scopes begin and end | |
14401 | (such as at the start of a function or a block of statements). This | |
14402 | error indicates that an inner scope block is not fully contained | |
14403 | in its outer scope blocks. | |
14404 | ||
14405 | @value{GDBN} circumvents the problem by treating the inner block as if it had | |
14406 | the same scope as the outer block. In the error message, @var{symbol} | |
14407 | may be shown as ``@code{(don't know)}'' if the outer block is not a | |
14408 | function. | |
14409 | ||
14410 | @item block at @var{address} out of order | |
14411 | ||
14412 | The symbol information for symbol scope blocks should occur in | |
14413 | order of increasing addresses. This error indicates that it does not | |
14414 | do so. | |
14415 | ||
14416 | @value{GDBN} does not circumvent this problem, and has trouble | |
14417 | locating symbols in the source file whose symbols it is reading. (You | |
14418 | can often determine what source file is affected by specifying | |
79a6e687 BW |
14419 | @code{set verbose on}. @xref{Messages/Warnings, ,Optional Warnings and |
14420 | Messages}.) | |
c906108c SS |
14421 | |
14422 | @item bad block start address patched | |
14423 | ||
14424 | The symbol information for a symbol scope block has a start address | |
14425 | smaller than the address of the preceding source line. This is known | |
14426 | to occur in the SunOS 4.1.1 (and earlier) C compiler. | |
14427 | ||
14428 | @value{GDBN} circumvents the problem by treating the symbol scope block as | |
14429 | starting on the previous source line. | |
14430 | ||
14431 | @item bad string table offset in symbol @var{n} | |
14432 | ||
14433 | @cindex foo | |
14434 | Symbol number @var{n} contains a pointer into the string table which is | |
14435 | larger than the size of the string table. | |
14436 | ||
14437 | @value{GDBN} circumvents the problem by considering the symbol to have the | |
14438 | name @code{foo}, which may cause other problems if many symbols end up | |
14439 | with this name. | |
14440 | ||
14441 | @item unknown symbol type @code{0x@var{nn}} | |
14442 | ||
7a292a7a SS |
14443 | The symbol information contains new data types that @value{GDBN} does |
14444 | not yet know how to read. @code{0x@var{nn}} is the symbol type of the | |
d4f3574e | 14445 | uncomprehended information, in hexadecimal. |
c906108c | 14446 | |
7a292a7a SS |
14447 | @value{GDBN} circumvents the error by ignoring this symbol information. |
14448 | This usually allows you to debug your program, though certain symbols | |
c906108c | 14449 | are not accessible. If you encounter such a problem and feel like |
7a292a7a SS |
14450 | debugging it, you can debug @code{@value{GDBP}} with itself, breakpoint |
14451 | on @code{complain}, then go up to the function @code{read_dbx_symtab} | |
14452 | and examine @code{*bufp} to see the symbol. | |
c906108c SS |
14453 | |
14454 | @item stub type has NULL name | |
c906108c | 14455 | |
7a292a7a | 14456 | @value{GDBN} could not find the full definition for a struct or class. |
c906108c | 14457 | |
7a292a7a | 14458 | @item const/volatile indicator missing (ok if using g++ v1.x), got@dots{} |
b37052ae | 14459 | The symbol information for a C@t{++} member function is missing some |
7a292a7a SS |
14460 | information that recent versions of the compiler should have output for |
14461 | it. | |
c906108c SS |
14462 | |
14463 | @item info mismatch between compiler and debugger | |
14464 | ||
14465 | @value{GDBN} could not parse a type specification output by the compiler. | |
7a292a7a | 14466 | |
c906108c SS |
14467 | @end table |
14468 | ||
b14b1491 TT |
14469 | @node Data Files |
14470 | @section GDB Data Files | |
14471 | ||
14472 | @cindex prefix for data files | |
14473 | @value{GDBN} will sometimes read an auxiliary data file. These files | |
14474 | are kept in a directory known as the @dfn{data directory}. | |
14475 | ||
14476 | You can set the data directory's name, and view the name @value{GDBN} | |
14477 | is currently using. | |
14478 | ||
14479 | @table @code | |
14480 | @kindex set data-directory | |
14481 | @item set data-directory @var{directory} | |
14482 | Set the directory which @value{GDBN} searches for auxiliary data files | |
14483 | to @var{directory}. | |
14484 | ||
14485 | @kindex show data-directory | |
14486 | @item show data-directory | |
14487 | Show the directory @value{GDBN} searches for auxiliary data files. | |
14488 | @end table | |
14489 | ||
14490 | @cindex default data directory | |
14491 | @cindex @samp{--with-gdb-datadir} | |
14492 | You can set the default data directory by using the configure-time | |
14493 | @samp{--with-gdb-datadir} option. If the data directory is inside | |
14494 | @value{GDBN}'s configured binary prefix (set with @samp{--prefix} or | |
14495 | @samp{--exec-prefix}), then the default data directory will be updated | |
14496 | automatically if the installed @value{GDBN} is moved to a new | |
14497 | location. | |
14498 | ||
6d2ebf8b | 14499 | @node Targets |
c906108c | 14500 | @chapter Specifying a Debugging Target |
7a292a7a | 14501 | |
c906108c | 14502 | @cindex debugging target |
c906108c | 14503 | A @dfn{target} is the execution environment occupied by your program. |
53a5351d JM |
14504 | |
14505 | Often, @value{GDBN} runs in the same host environment as your program; | |
14506 | in that case, the debugging target is specified as a side effect when | |
14507 | you use the @code{file} or @code{core} commands. When you need more | |
c906108c SS |
14508 | flexibility---for example, running @value{GDBN} on a physically separate |
14509 | host, or controlling a standalone system over a serial port or a | |
53a5351d JM |
14510 | realtime system over a TCP/IP connection---you can use the @code{target} |
14511 | command to specify one of the target types configured for @value{GDBN} | |
79a6e687 | 14512 | (@pxref{Target Commands, ,Commands for Managing Targets}). |
c906108c | 14513 | |
a8f24a35 EZ |
14514 | @cindex target architecture |
14515 | It is possible to build @value{GDBN} for several different @dfn{target | |
14516 | architectures}. When @value{GDBN} is built like that, you can choose | |
14517 | one of the available architectures with the @kbd{set architecture} | |
14518 | command. | |
14519 | ||
14520 | @table @code | |
14521 | @kindex set architecture | |
14522 | @kindex show architecture | |
14523 | @item set architecture @var{arch} | |
14524 | This command sets the current target architecture to @var{arch}. The | |
14525 | value of @var{arch} can be @code{"auto"}, in addition to one of the | |
14526 | supported architectures. | |
14527 | ||
14528 | @item show architecture | |
14529 | Show the current target architecture. | |
9c16f35a EZ |
14530 | |
14531 | @item set processor | |
14532 | @itemx processor | |
14533 | @kindex set processor | |
14534 | @kindex show processor | |
14535 | These are alias commands for, respectively, @code{set architecture} | |
14536 | and @code{show architecture}. | |
a8f24a35 EZ |
14537 | @end table |
14538 | ||
c906108c SS |
14539 | @menu |
14540 | * Active Targets:: Active targets | |
14541 | * Target Commands:: Commands for managing targets | |
c906108c | 14542 | * Byte Order:: Choosing target byte order |
c906108c SS |
14543 | @end menu |
14544 | ||
6d2ebf8b | 14545 | @node Active Targets |
79a6e687 | 14546 | @section Active Targets |
7a292a7a | 14547 | |
c906108c SS |
14548 | @cindex stacking targets |
14549 | @cindex active targets | |
14550 | @cindex multiple targets | |
14551 | ||
c906108c | 14552 | There are three classes of targets: processes, core files, and |
7a292a7a SS |
14553 | executable files. @value{GDBN} can work concurrently on up to three |
14554 | active targets, one in each class. This allows you to (for example) | |
14555 | start a process and inspect its activity without abandoning your work on | |
14556 | a core file. | |
c906108c SS |
14557 | |
14558 | For example, if you execute @samp{gdb a.out}, then the executable file | |
14559 | @code{a.out} is the only active target. If you designate a core file as | |
14560 | well---presumably from a prior run that crashed and coredumped---then | |
14561 | @value{GDBN} has two active targets and uses them in tandem, looking | |
14562 | first in the corefile target, then in the executable file, to satisfy | |
14563 | requests for memory addresses. (Typically, these two classes of target | |
14564 | are complementary, since core files contain only a program's | |
14565 | read-write memory---variables and so on---plus machine status, while | |
14566 | executable files contain only the program text and initialized data.) | |
c906108c SS |
14567 | |
14568 | When you type @code{run}, your executable file becomes an active process | |
7a292a7a SS |
14569 | target as well. When a process target is active, all @value{GDBN} |
14570 | commands requesting memory addresses refer to that target; addresses in | |
14571 | an active core file or executable file target are obscured while the | |
14572 | process target is active. | |
c906108c | 14573 | |
7a292a7a | 14574 | Use the @code{core-file} and @code{exec-file} commands to select a new |
79a6e687 BW |
14575 | core file or executable target (@pxref{Files, ,Commands to Specify |
14576 | Files}). To specify as a target a process that is already running, use | |
14577 | the @code{attach} command (@pxref{Attach, ,Debugging an Already-running | |
14578 | Process}). | |
c906108c | 14579 | |
6d2ebf8b | 14580 | @node Target Commands |
79a6e687 | 14581 | @section Commands for Managing Targets |
c906108c SS |
14582 | |
14583 | @table @code | |
14584 | @item target @var{type} @var{parameters} | |
7a292a7a SS |
14585 | Connects the @value{GDBN} host environment to a target machine or |
14586 | process. A target is typically a protocol for talking to debugging | |
14587 | facilities. You use the argument @var{type} to specify the type or | |
14588 | protocol of the target machine. | |
c906108c SS |
14589 | |
14590 | Further @var{parameters} are interpreted by the target protocol, but | |
14591 | typically include things like device names or host names to connect | |
14592 | with, process numbers, and baud rates. | |
c906108c SS |
14593 | |
14594 | The @code{target} command does not repeat if you press @key{RET} again | |
14595 | after executing the command. | |
14596 | ||
14597 | @kindex help target | |
14598 | @item help target | |
14599 | Displays the names of all targets available. To display targets | |
14600 | currently selected, use either @code{info target} or @code{info files} | |
79a6e687 | 14601 | (@pxref{Files, ,Commands to Specify Files}). |
c906108c SS |
14602 | |
14603 | @item help target @var{name} | |
14604 | Describe a particular target, including any parameters necessary to | |
14605 | select it. | |
14606 | ||
14607 | @kindex set gnutarget | |
14608 | @item set gnutarget @var{args} | |
5d161b24 | 14609 | @value{GDBN} uses its own library BFD to read your files. @value{GDBN} |
c906108c | 14610 | knows whether it is reading an @dfn{executable}, |
5d161b24 DB |
14611 | a @dfn{core}, or a @dfn{.o} file; however, you can specify the file format |
14612 | with the @code{set gnutarget} command. Unlike most @code{target} commands, | |
c906108c SS |
14613 | with @code{gnutarget} the @code{target} refers to a program, not a machine. |
14614 | ||
d4f3574e | 14615 | @quotation |
c906108c SS |
14616 | @emph{Warning:} To specify a file format with @code{set gnutarget}, |
14617 | you must know the actual BFD name. | |
d4f3574e | 14618 | @end quotation |
c906108c | 14619 | |
d4f3574e | 14620 | @noindent |
79a6e687 | 14621 | @xref{Files, , Commands to Specify Files}. |
c906108c | 14622 | |
5d161b24 | 14623 | @kindex show gnutarget |
c906108c SS |
14624 | @item show gnutarget |
14625 | Use the @code{show gnutarget} command to display what file format | |
14626 | @code{gnutarget} is set to read. If you have not set @code{gnutarget}, | |
14627 | @value{GDBN} will determine the file format for each file automatically, | |
14628 | and @code{show gnutarget} displays @samp{The current BDF target is "auto"}. | |
14629 | @end table | |
14630 | ||
4644b6e3 | 14631 | @cindex common targets |
c906108c SS |
14632 | Here are some common targets (available, or not, depending on the GDB |
14633 | configuration): | |
c906108c SS |
14634 | |
14635 | @table @code | |
4644b6e3 | 14636 | @kindex target |
c906108c | 14637 | @item target exec @var{program} |
4644b6e3 | 14638 | @cindex executable file target |
c906108c SS |
14639 | An executable file. @samp{target exec @var{program}} is the same as |
14640 | @samp{exec-file @var{program}}. | |
14641 | ||
c906108c | 14642 | @item target core @var{filename} |
4644b6e3 | 14643 | @cindex core dump file target |
c906108c SS |
14644 | A core dump file. @samp{target core @var{filename}} is the same as |
14645 | @samp{core-file @var{filename}}. | |
c906108c | 14646 | |
1a10341b | 14647 | @item target remote @var{medium} |
4644b6e3 | 14648 | @cindex remote target |
1a10341b JB |
14649 | A remote system connected to @value{GDBN} via a serial line or network |
14650 | connection. This command tells @value{GDBN} to use its own remote | |
14651 | protocol over @var{medium} for debugging. @xref{Remote Debugging}. | |
14652 | ||
14653 | For example, if you have a board connected to @file{/dev/ttya} on the | |
14654 | machine running @value{GDBN}, you could say: | |
14655 | ||
14656 | @smallexample | |
14657 | target remote /dev/ttya | |
14658 | @end smallexample | |
14659 | ||
14660 | @code{target remote} supports the @code{load} command. This is only | |
14661 | useful if you have some other way of getting the stub to the target | |
14662 | system, and you can put it somewhere in memory where it won't get | |
14663 | clobbered by the download. | |
c906108c | 14664 | |
c906108c | 14665 | @item target sim |
4644b6e3 | 14666 | @cindex built-in simulator target |
2df3850c | 14667 | Builtin CPU simulator. @value{GDBN} includes simulators for most architectures. |
104c1213 | 14668 | In general, |
474c8240 | 14669 | @smallexample |
104c1213 JM |
14670 | target sim |
14671 | load | |
14672 | run | |
474c8240 | 14673 | @end smallexample |
d4f3574e | 14674 | @noindent |
104c1213 | 14675 | works; however, you cannot assume that a specific memory map, device |
d4f3574e | 14676 | drivers, or even basic I/O is available, although some simulators do |
104c1213 JM |
14677 | provide these. For info about any processor-specific simulator details, |
14678 | see the appropriate section in @ref{Embedded Processors, ,Embedded | |
14679 | Processors}. | |
14680 | ||
c906108c SS |
14681 | @end table |
14682 | ||
104c1213 | 14683 | Some configurations may include these targets as well: |
c906108c SS |
14684 | |
14685 | @table @code | |
14686 | ||
c906108c | 14687 | @item target nrom @var{dev} |
4644b6e3 | 14688 | @cindex NetROM ROM emulator target |
c906108c SS |
14689 | NetROM ROM emulator. This target only supports downloading. |
14690 | ||
c906108c SS |
14691 | @end table |
14692 | ||
5d161b24 | 14693 | Different targets are available on different configurations of @value{GDBN}; |
c906108c | 14694 | your configuration may have more or fewer targets. |
c906108c | 14695 | |
721c2651 EZ |
14696 | Many remote targets require you to download the executable's code once |
14697 | you've successfully established a connection. You may wish to control | |
3d00d119 DJ |
14698 | various aspects of this process. |
14699 | ||
14700 | @table @code | |
721c2651 EZ |
14701 | |
14702 | @item set hash | |
14703 | @kindex set hash@r{, for remote monitors} | |
14704 | @cindex hash mark while downloading | |
14705 | This command controls whether a hash mark @samp{#} is displayed while | |
14706 | downloading a file to the remote monitor. If on, a hash mark is | |
14707 | displayed after each S-record is successfully downloaded to the | |
14708 | monitor. | |
14709 | ||
14710 | @item show hash | |
14711 | @kindex show hash@r{, for remote monitors} | |
14712 | Show the current status of displaying the hash mark. | |
14713 | ||
14714 | @item set debug monitor | |
14715 | @kindex set debug monitor | |
14716 | @cindex display remote monitor communications | |
14717 | Enable or disable display of communications messages between | |
14718 | @value{GDBN} and the remote monitor. | |
14719 | ||
14720 | @item show debug monitor | |
14721 | @kindex show debug monitor | |
14722 | Show the current status of displaying communications between | |
14723 | @value{GDBN} and the remote monitor. | |
a8f24a35 | 14724 | @end table |
c906108c SS |
14725 | |
14726 | @table @code | |
14727 | ||
14728 | @kindex load @var{filename} | |
14729 | @item load @var{filename} | |
8edfe269 | 14730 | @anchor{load} |
c906108c SS |
14731 | Depending on what remote debugging facilities are configured into |
14732 | @value{GDBN}, the @code{load} command may be available. Where it exists, it | |
14733 | is meant to make @var{filename} (an executable) available for debugging | |
14734 | on the remote system---by downloading, or dynamic linking, for example. | |
14735 | @code{load} also records the @var{filename} symbol table in @value{GDBN}, like | |
14736 | the @code{add-symbol-file} command. | |
14737 | ||
14738 | If your @value{GDBN} does not have a @code{load} command, attempting to | |
14739 | execute it gets the error message ``@code{You can't do that when your | |
14740 | target is @dots{}}'' | |
c906108c SS |
14741 | |
14742 | The file is loaded at whatever address is specified in the executable. | |
14743 | For some object file formats, you can specify the load address when you | |
14744 | link the program; for other formats, like a.out, the object file format | |
14745 | specifies a fixed address. | |
14746 | @c FIXME! This would be a good place for an xref to the GNU linker doc. | |
14747 | ||
68437a39 DJ |
14748 | Depending on the remote side capabilities, @value{GDBN} may be able to |
14749 | load programs into flash memory. | |
14750 | ||
c906108c SS |
14751 | @code{load} does not repeat if you press @key{RET} again after using it. |
14752 | @end table | |
14753 | ||
6d2ebf8b | 14754 | @node Byte Order |
79a6e687 | 14755 | @section Choosing Target Byte Order |
7a292a7a | 14756 | |
c906108c SS |
14757 | @cindex choosing target byte order |
14758 | @cindex target byte order | |
c906108c | 14759 | |
172c2a43 | 14760 | Some types of processors, such as the MIPS, PowerPC, and Renesas SH, |
c906108c SS |
14761 | offer the ability to run either big-endian or little-endian byte |
14762 | orders. Usually the executable or symbol will include a bit to | |
14763 | designate the endian-ness, and you will not need to worry about | |
14764 | which to use. However, you may still find it useful to adjust | |
d4f3574e | 14765 | @value{GDBN}'s idea of processor endian-ness manually. |
c906108c SS |
14766 | |
14767 | @table @code | |
4644b6e3 | 14768 | @kindex set endian |
c906108c SS |
14769 | @item set endian big |
14770 | Instruct @value{GDBN} to assume the target is big-endian. | |
14771 | ||
c906108c SS |
14772 | @item set endian little |
14773 | Instruct @value{GDBN} to assume the target is little-endian. | |
14774 | ||
c906108c SS |
14775 | @item set endian auto |
14776 | Instruct @value{GDBN} to use the byte order associated with the | |
14777 | executable. | |
14778 | ||
14779 | @item show endian | |
14780 | Display @value{GDBN}'s current idea of the target byte order. | |
14781 | ||
14782 | @end table | |
14783 | ||
14784 | Note that these commands merely adjust interpretation of symbolic | |
14785 | data on the host, and that they have absolutely no effect on the | |
14786 | target system. | |
14787 | ||
ea35711c DJ |
14788 | |
14789 | @node Remote Debugging | |
14790 | @chapter Debugging Remote Programs | |
c906108c SS |
14791 | @cindex remote debugging |
14792 | ||
14793 | If you are trying to debug a program running on a machine that cannot run | |
5d161b24 DB |
14794 | @value{GDBN} in the usual way, it is often useful to use remote debugging. |
14795 | For example, you might use remote debugging on an operating system kernel, | |
c906108c SS |
14796 | or on a small system which does not have a general purpose operating system |
14797 | powerful enough to run a full-featured debugger. | |
14798 | ||
14799 | Some configurations of @value{GDBN} have special serial or TCP/IP interfaces | |
14800 | to make this work with particular debugging targets. In addition, | |
5d161b24 | 14801 | @value{GDBN} comes with a generic serial protocol (specific to @value{GDBN}, |
c906108c SS |
14802 | but not specific to any particular target system) which you can use if you |
14803 | write the remote stubs---the code that runs on the remote system to | |
14804 | communicate with @value{GDBN}. | |
14805 | ||
14806 | Other remote targets may be available in your | |
14807 | configuration of @value{GDBN}; use @code{help target} to list them. | |
c906108c | 14808 | |
6b2f586d | 14809 | @menu |
07f31aa6 | 14810 | * Connecting:: Connecting to a remote target |
a6b151f1 | 14811 | * File Transfer:: Sending files to a remote system |
6b2f586d | 14812 | * Server:: Using the gdbserver program |
79a6e687 BW |
14813 | * Remote Configuration:: Remote configuration |
14814 | * Remote Stub:: Implementing a remote stub | |
6b2f586d AC |
14815 | @end menu |
14816 | ||
07f31aa6 | 14817 | @node Connecting |
79a6e687 | 14818 | @section Connecting to a Remote Target |
07f31aa6 DJ |
14819 | |
14820 | On the @value{GDBN} host machine, you will need an unstripped copy of | |
d3e8051b | 14821 | your program, since @value{GDBN} needs symbol and debugging information. |
07f31aa6 DJ |
14822 | Start up @value{GDBN} as usual, using the name of the local copy of your |
14823 | program as the first argument. | |
14824 | ||
86941c27 JB |
14825 | @cindex @code{target remote} |
14826 | @value{GDBN} can communicate with the target over a serial line, or | |
14827 | over an @acronym{IP} network using @acronym{TCP} or @acronym{UDP}. In | |
14828 | each case, @value{GDBN} uses the same protocol for debugging your | |
14829 | program; only the medium carrying the debugging packets varies. The | |
14830 | @code{target remote} command establishes a connection to the target. | |
14831 | Its arguments indicate which medium to use: | |
14832 | ||
14833 | @table @code | |
14834 | ||
14835 | @item target remote @var{serial-device} | |
07f31aa6 | 14836 | @cindex serial line, @code{target remote} |
86941c27 JB |
14837 | Use @var{serial-device} to communicate with the target. For example, |
14838 | to use a serial line connected to the device named @file{/dev/ttyb}: | |
14839 | ||
14840 | @smallexample | |
14841 | target remote /dev/ttyb | |
14842 | @end smallexample | |
14843 | ||
07f31aa6 DJ |
14844 | If you're using a serial line, you may want to give @value{GDBN} the |
14845 | @w{@samp{--baud}} option, or use the @code{set remotebaud} command | |
79a6e687 | 14846 | (@pxref{Remote Configuration, set remotebaud}) before the |
9c16f35a | 14847 | @code{target} command. |
07f31aa6 | 14848 | |
86941c27 JB |
14849 | @item target remote @code{@var{host}:@var{port}} |
14850 | @itemx target remote @code{tcp:@var{host}:@var{port}} | |
14851 | @cindex @acronym{TCP} port, @code{target remote} | |
14852 | Debug using a @acronym{TCP} connection to @var{port} on @var{host}. | |
14853 | The @var{host} may be either a host name or a numeric @acronym{IP} | |
14854 | address; @var{port} must be a decimal number. The @var{host} could be | |
14855 | the target machine itself, if it is directly connected to the net, or | |
14856 | it might be a terminal server which in turn has a serial line to the | |
14857 | target. | |
07f31aa6 | 14858 | |
86941c27 JB |
14859 | For example, to connect to port 2828 on a terminal server named |
14860 | @code{manyfarms}: | |
07f31aa6 DJ |
14861 | |
14862 | @smallexample | |
14863 | target remote manyfarms:2828 | |
14864 | @end smallexample | |
14865 | ||
86941c27 JB |
14866 | If your remote target is actually running on the same machine as your |
14867 | debugger session (e.g.@: a simulator for your target running on the | |
14868 | same host), you can omit the hostname. For example, to connect to | |
14869 | port 1234 on your local machine: | |
07f31aa6 DJ |
14870 | |
14871 | @smallexample | |
14872 | target remote :1234 | |
14873 | @end smallexample | |
14874 | @noindent | |
14875 | ||
14876 | Note that the colon is still required here. | |
14877 | ||
86941c27 JB |
14878 | @item target remote @code{udp:@var{host}:@var{port}} |
14879 | @cindex @acronym{UDP} port, @code{target remote} | |
14880 | Debug using @acronym{UDP} packets to @var{port} on @var{host}. For example, to | |
14881 | connect to @acronym{UDP} port 2828 on a terminal server named @code{manyfarms}: | |
07f31aa6 DJ |
14882 | |
14883 | @smallexample | |
14884 | target remote udp:manyfarms:2828 | |
14885 | @end smallexample | |
14886 | ||
86941c27 JB |
14887 | When using a @acronym{UDP} connection for remote debugging, you should |
14888 | keep in mind that the `U' stands for ``Unreliable''. @acronym{UDP} | |
14889 | can silently drop packets on busy or unreliable networks, which will | |
14890 | cause havoc with your debugging session. | |
14891 | ||
66b8c7f6 JB |
14892 | @item target remote | @var{command} |
14893 | @cindex pipe, @code{target remote} to | |
14894 | Run @var{command} in the background and communicate with it using a | |
14895 | pipe. The @var{command} is a shell command, to be parsed and expanded | |
14896 | by the system's command shell, @code{/bin/sh}; it should expect remote | |
14897 | protocol packets on its standard input, and send replies on its | |
14898 | standard output. You could use this to run a stand-alone simulator | |
14899 | that speaks the remote debugging protocol, to make net connections | |
14900 | using programs like @code{ssh}, or for other similar tricks. | |
14901 | ||
14902 | If @var{command} closes its standard output (perhaps by exiting), | |
14903 | @value{GDBN} will try to send it a @code{SIGTERM} signal. (If the | |
14904 | program has already exited, this will have no effect.) | |
14905 | ||
86941c27 | 14906 | @end table |
07f31aa6 | 14907 | |
86941c27 | 14908 | Once the connection has been established, you can use all the usual |
8edfe269 DJ |
14909 | commands to examine and change data. The remote program is already |
14910 | running; you can use @kbd{step} and @kbd{continue}, and you do not | |
14911 | need to use @kbd{run}. | |
07f31aa6 DJ |
14912 | |
14913 | @cindex interrupting remote programs | |
14914 | @cindex remote programs, interrupting | |
14915 | Whenever @value{GDBN} is waiting for the remote program, if you type the | |
c8aa23ab | 14916 | interrupt character (often @kbd{Ctrl-c}), @value{GDBN} attempts to stop the |
07f31aa6 DJ |
14917 | program. This may or may not succeed, depending in part on the hardware |
14918 | and the serial drivers the remote system uses. If you type the | |
14919 | interrupt character once again, @value{GDBN} displays this prompt: | |
14920 | ||
14921 | @smallexample | |
14922 | Interrupted while waiting for the program. | |
14923 | Give up (and stop debugging it)? (y or n) | |
14924 | @end smallexample | |
14925 | ||
14926 | If you type @kbd{y}, @value{GDBN} abandons the remote debugging session. | |
14927 | (If you decide you want to try again later, you can use @samp{target | |
14928 | remote} again to connect once more.) If you type @kbd{n}, @value{GDBN} | |
14929 | goes back to waiting. | |
14930 | ||
14931 | @table @code | |
14932 | @kindex detach (remote) | |
14933 | @item detach | |
14934 | When you have finished debugging the remote program, you can use the | |
14935 | @code{detach} command to release it from @value{GDBN} control. | |
14936 | Detaching from the target normally resumes its execution, but the results | |
14937 | will depend on your particular remote stub. After the @code{detach} | |
14938 | command, @value{GDBN} is free to connect to another target. | |
14939 | ||
14940 | @kindex disconnect | |
14941 | @item disconnect | |
14942 | The @code{disconnect} command behaves like @code{detach}, except that | |
14943 | the target is generally not resumed. It will wait for @value{GDBN} | |
14944 | (this instance or another one) to connect and continue debugging. After | |
14945 | the @code{disconnect} command, @value{GDBN} is again free to connect to | |
14946 | another target. | |
09d4efe1 EZ |
14947 | |
14948 | @cindex send command to remote monitor | |
fad38dfa EZ |
14949 | @cindex extend @value{GDBN} for remote targets |
14950 | @cindex add new commands for external monitor | |
09d4efe1 EZ |
14951 | @kindex monitor |
14952 | @item monitor @var{cmd} | |
fad38dfa EZ |
14953 | This command allows you to send arbitrary commands directly to the |
14954 | remote monitor. Since @value{GDBN} doesn't care about the commands it | |
14955 | sends like this, this command is the way to extend @value{GDBN}---you | |
14956 | can add new commands that only the external monitor will understand | |
14957 | and implement. | |
07f31aa6 DJ |
14958 | @end table |
14959 | ||
a6b151f1 DJ |
14960 | @node File Transfer |
14961 | @section Sending files to a remote system | |
14962 | @cindex remote target, file transfer | |
14963 | @cindex file transfer | |
14964 | @cindex sending files to remote systems | |
14965 | ||
14966 | Some remote targets offer the ability to transfer files over the same | |
14967 | connection used to communicate with @value{GDBN}. This is convenient | |
14968 | for targets accessible through other means, e.g.@: @sc{gnu}/Linux systems | |
14969 | running @code{gdbserver} over a network interface. For other targets, | |
14970 | e.g.@: embedded devices with only a single serial port, this may be | |
14971 | the only way to upload or download files. | |
14972 | ||
14973 | Not all remote targets support these commands. | |
14974 | ||
14975 | @table @code | |
14976 | @kindex remote put | |
14977 | @item remote put @var{hostfile} @var{targetfile} | |
14978 | Copy file @var{hostfile} from the host system (the machine running | |
14979 | @value{GDBN}) to @var{targetfile} on the target system. | |
14980 | ||
14981 | @kindex remote get | |
14982 | @item remote get @var{targetfile} @var{hostfile} | |
14983 | Copy file @var{targetfile} from the target system to @var{hostfile} | |
14984 | on the host system. | |
14985 | ||
14986 | @kindex remote delete | |
14987 | @item remote delete @var{targetfile} | |
14988 | Delete @var{targetfile} from the target system. | |
14989 | ||
14990 | @end table | |
14991 | ||
6f05cf9f | 14992 | @node Server |
79a6e687 | 14993 | @section Using the @code{gdbserver} Program |
6f05cf9f AC |
14994 | |
14995 | @kindex gdbserver | |
14996 | @cindex remote connection without stubs | |
14997 | @code{gdbserver} is a control program for Unix-like systems, which | |
14998 | allows you to connect your program with a remote @value{GDBN} via | |
14999 | @code{target remote}---but without linking in the usual debugging stub. | |
15000 | ||
15001 | @code{gdbserver} is not a complete replacement for the debugging stubs, | |
15002 | because it requires essentially the same operating-system facilities | |
15003 | that @value{GDBN} itself does. In fact, a system that can run | |
15004 | @code{gdbserver} to connect to a remote @value{GDBN} could also run | |
15005 | @value{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless, | |
15006 | because it is a much smaller program than @value{GDBN} itself. It is | |
15007 | also easier to port than all of @value{GDBN}, so you may be able to get | |
15008 | started more quickly on a new system by using @code{gdbserver}. | |
15009 | Finally, if you develop code for real-time systems, you may find that | |
15010 | the tradeoffs involved in real-time operation make it more convenient to | |
15011 | do as much development work as possible on another system, for example | |
15012 | by cross-compiling. You can use @code{gdbserver} to make a similar | |
15013 | choice for debugging. | |
15014 | ||
15015 | @value{GDBN} and @code{gdbserver} communicate via either a serial line | |
15016 | or a TCP connection, using the standard @value{GDBN} remote serial | |
15017 | protocol. | |
15018 | ||
2d717e4f DJ |
15019 | @quotation |
15020 | @emph{Warning:} @code{gdbserver} does not have any built-in security. | |
15021 | Do not run @code{gdbserver} connected to any public network; a | |
15022 | @value{GDBN} connection to @code{gdbserver} provides access to the | |
15023 | target system with the same privileges as the user running | |
15024 | @code{gdbserver}. | |
15025 | @end quotation | |
15026 | ||
15027 | @subsection Running @code{gdbserver} | |
15028 | @cindex arguments, to @code{gdbserver} | |
15029 | ||
15030 | Run @code{gdbserver} on the target system. You need a copy of the | |
15031 | program you want to debug, including any libraries it requires. | |
6f05cf9f AC |
15032 | @code{gdbserver} does not need your program's symbol table, so you can |
15033 | strip the program if necessary to save space. @value{GDBN} on the host | |
15034 | system does all the symbol handling. | |
15035 | ||
15036 | To use the server, you must tell it how to communicate with @value{GDBN}; | |
56460a61 | 15037 | the name of your program; and the arguments for your program. The usual |
6f05cf9f AC |
15038 | syntax is: |
15039 | ||
15040 | @smallexample | |
15041 | target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ] | |
15042 | @end smallexample | |
15043 | ||
15044 | @var{comm} is either a device name (to use a serial line) or a TCP | |
15045 | hostname and portnumber. For example, to debug Emacs with the argument | |
15046 | @samp{foo.txt} and communicate with @value{GDBN} over the serial port | |
15047 | @file{/dev/com1}: | |
15048 | ||
15049 | @smallexample | |
15050 | target> gdbserver /dev/com1 emacs foo.txt | |
15051 | @end smallexample | |
15052 | ||
15053 | @code{gdbserver} waits passively for the host @value{GDBN} to communicate | |
15054 | with it. | |
15055 | ||
15056 | To use a TCP connection instead of a serial line: | |
15057 | ||
15058 | @smallexample | |
15059 | target> gdbserver host:2345 emacs foo.txt | |
15060 | @end smallexample | |
15061 | ||
15062 | The only difference from the previous example is the first argument, | |
15063 | specifying that you are communicating with the host @value{GDBN} via | |
15064 | TCP. The @samp{host:2345} argument means that @code{gdbserver} is to | |
15065 | expect a TCP connection from machine @samp{host} to local TCP port 2345. | |
15066 | (Currently, the @samp{host} part is ignored.) You can choose any number | |
15067 | you want for the port number as long as it does not conflict with any | |
15068 | TCP ports already in use on the target system (for example, @code{23} is | |
15069 | reserved for @code{telnet}).@footnote{If you choose a port number that | |
15070 | conflicts with another service, @code{gdbserver} prints an error message | |
15071 | and exits.} You must use the same port number with the host @value{GDBN} | |
15072 | @code{target remote} command. | |
15073 | ||
2d717e4f DJ |
15074 | @subsubsection Attaching to a Running Program |
15075 | ||
56460a61 DJ |
15076 | On some targets, @code{gdbserver} can also attach to running programs. |
15077 | This is accomplished via the @code{--attach} argument. The syntax is: | |
15078 | ||
15079 | @smallexample | |
2d717e4f | 15080 | target> gdbserver --attach @var{comm} @var{pid} |
56460a61 DJ |
15081 | @end smallexample |
15082 | ||
15083 | @var{pid} is the process ID of a currently running process. It isn't necessary | |
15084 | to point @code{gdbserver} at a binary for the running process. | |
15085 | ||
b1fe9455 DJ |
15086 | @pindex pidof |
15087 | @cindex attach to a program by name | |
15088 | You can debug processes by name instead of process ID if your target has the | |
15089 | @code{pidof} utility: | |
15090 | ||
15091 | @smallexample | |
2d717e4f | 15092 | target> gdbserver --attach @var{comm} `pidof @var{program}` |
b1fe9455 DJ |
15093 | @end smallexample |
15094 | ||
f822c95b | 15095 | In case more than one copy of @var{program} is running, or @var{program} |
b1fe9455 DJ |
15096 | has multiple threads, most versions of @code{pidof} support the |
15097 | @code{-s} option to only return the first process ID. | |
15098 | ||
2d717e4f DJ |
15099 | @subsubsection Multi-Process Mode for @code{gdbserver} |
15100 | @cindex gdbserver, multiple processes | |
15101 | @cindex multiple processes with gdbserver | |
15102 | ||
15103 | When you connect to @code{gdbserver} using @code{target remote}, | |
15104 | @code{gdbserver} debugs the specified program only once. When the | |
15105 | program exits, or you detach from it, @value{GDBN} closes the connection | |
15106 | and @code{gdbserver} exits. | |
15107 | ||
6e6c6f50 | 15108 | If you connect using @kbd{target extended-remote}, @code{gdbserver} |
2d717e4f DJ |
15109 | enters multi-process mode. When the debugged program exits, or you |
15110 | detach from it, @value{GDBN} stays connected to @code{gdbserver} even | |
15111 | though no program is running. The @code{run} and @code{attach} | |
15112 | commands instruct @code{gdbserver} to run or attach to a new program. | |
15113 | The @code{run} command uses @code{set remote exec-file} (@pxref{set | |
15114 | remote exec-file}) to select the program to run. Command line | |
15115 | arguments are supported, except for wildcard expansion and I/O | |
15116 | redirection (@pxref{Arguments}). | |
15117 | ||
15118 | To start @code{gdbserver} without supplying an initial command to run | |
15119 | or process ID to attach, use the @option{--multi} command line option. | |
6e6c6f50 | 15120 | Then you can connect using @kbd{target extended-remote} and start |
2d717e4f DJ |
15121 | the program you want to debug. |
15122 | ||
15123 | @code{gdbserver} does not automatically exit in multi-process mode. | |
15124 | You can terminate it by using @code{monitor exit} | |
15125 | (@pxref{Monitor Commands for gdbserver}). | |
15126 | ||
15127 | @subsubsection Other Command-Line Arguments for @code{gdbserver} | |
15128 | ||
62709adf PA |
15129 | The @option{--debug} option tells @code{gdbserver} to display extra |
15130 | status information about the debugging process. The | |
15131 | @option{--remote-debug} option tells @code{gdbserver} to display | |
15132 | remote protocol debug output. These options are intended for | |
15133 | @code{gdbserver} development and for bug reports to the developers. | |
2d717e4f | 15134 | |
ccd213ac DJ |
15135 | The @option{--wrapper} option specifies a wrapper to launch programs |
15136 | for debugging. The option should be followed by the name of the | |
15137 | wrapper, then any command-line arguments to pass to the wrapper, then | |
15138 | @kbd{--} indicating the end of the wrapper arguments. | |
15139 | ||
15140 | @code{gdbserver} runs the specified wrapper program with a combined | |
15141 | command line including the wrapper arguments, then the name of the | |
15142 | program to debug, then any arguments to the program. The wrapper | |
15143 | runs until it executes your program, and then @value{GDBN} gains control. | |
15144 | ||
15145 | You can use any program that eventually calls @code{execve} with | |
15146 | its arguments as a wrapper. Several standard Unix utilities do | |
15147 | this, e.g.@: @code{env} and @code{nohup}. Any Unix shell script ending | |
15148 | with @code{exec "$@@"} will also work. | |
15149 | ||
15150 | For example, you can use @code{env} to pass an environment variable to | |
15151 | the debugged program, without setting the variable in @code{gdbserver}'s | |
15152 | environment: | |
15153 | ||
15154 | @smallexample | |
15155 | $ gdbserver --wrapper env LD_PRELOAD=libtest.so -- :2222 ./testprog | |
15156 | @end smallexample | |
15157 | ||
2d717e4f DJ |
15158 | @subsection Connecting to @code{gdbserver} |
15159 | ||
15160 | Run @value{GDBN} on the host system. | |
15161 | ||
15162 | First make sure you have the necessary symbol files. Load symbols for | |
f822c95b DJ |
15163 | your application using the @code{file} command before you connect. Use |
15164 | @code{set sysroot} to locate target libraries (unless your @value{GDBN} | |
2d717e4f | 15165 | was compiled with the correct sysroot using @code{--with-sysroot}). |
f822c95b DJ |
15166 | |
15167 | The symbol file and target libraries must exactly match the executable | |
15168 | and libraries on the target, with one exception: the files on the host | |
15169 | system should not be stripped, even if the files on the target system | |
15170 | are. Mismatched or missing files will lead to confusing results | |
15171 | during debugging. On @sc{gnu}/Linux targets, mismatched or missing | |
15172 | files may also prevent @code{gdbserver} from debugging multi-threaded | |
15173 | programs. | |
15174 | ||
79a6e687 | 15175 | Connect to your target (@pxref{Connecting,,Connecting to a Remote Target}). |
6f05cf9f AC |
15176 | For TCP connections, you must start up @code{gdbserver} prior to using |
15177 | the @code{target remote} command. Otherwise you may get an error whose | |
15178 | text depends on the host system, but which usually looks something like | |
2d717e4f | 15179 | @samp{Connection refused}. Don't use the @code{load} |
397ca115 | 15180 | command in @value{GDBN} when using @code{gdbserver}, since the program is |
f822c95b | 15181 | already on the target. |
07f31aa6 | 15182 | |
79a6e687 | 15183 | @subsection Monitor Commands for @code{gdbserver} |
c74d0ad8 | 15184 | @cindex monitor commands, for @code{gdbserver} |
2d717e4f | 15185 | @anchor{Monitor Commands for gdbserver} |
c74d0ad8 DJ |
15186 | |
15187 | During a @value{GDBN} session using @code{gdbserver}, you can use the | |
15188 | @code{monitor} command to send special requests to @code{gdbserver}. | |
2d717e4f | 15189 | Here are the available commands. |
c74d0ad8 DJ |
15190 | |
15191 | @table @code | |
15192 | @item monitor help | |
15193 | List the available monitor commands. | |
15194 | ||
15195 | @item monitor set debug 0 | |
15196 | @itemx monitor set debug 1 | |
15197 | Disable or enable general debugging messages. | |
15198 | ||
15199 | @item monitor set remote-debug 0 | |
15200 | @itemx monitor set remote-debug 1 | |
15201 | Disable or enable specific debugging messages associated with the remote | |
15202 | protocol (@pxref{Remote Protocol}). | |
15203 | ||
cdbfd419 PP |
15204 | @item monitor set libthread-db-search-path [PATH] |
15205 | @cindex gdbserver, search path for @code{libthread_db} | |
15206 | When this command is issued, @var{path} is a colon-separated list of | |
15207 | directories to search for @code{libthread_db} (@pxref{Threads,,set | |
15208 | libthread-db-search-path}). If you omit @var{path}, | |
15209 | @samp{libthread-db-search-path} will be reset to an empty list. | |
15210 | ||
2d717e4f DJ |
15211 | @item monitor exit |
15212 | Tell gdbserver to exit immediately. This command should be followed by | |
15213 | @code{disconnect} to close the debugging session. @code{gdbserver} will | |
15214 | detach from any attached processes and kill any processes it created. | |
15215 | Use @code{monitor exit} to terminate @code{gdbserver} at the end | |
15216 | of a multi-process mode debug session. | |
15217 | ||
c74d0ad8 DJ |
15218 | @end table |
15219 | ||
79a6e687 BW |
15220 | @node Remote Configuration |
15221 | @section Remote Configuration | |
501eef12 | 15222 | |
9c16f35a EZ |
15223 | @kindex set remote |
15224 | @kindex show remote | |
15225 | This section documents the configuration options available when | |
15226 | debugging remote programs. For the options related to the File I/O | |
fc320d37 | 15227 | extensions of the remote protocol, see @ref{system, |
9c16f35a | 15228 | system-call-allowed}. |
501eef12 AC |
15229 | |
15230 | @table @code | |
9c16f35a | 15231 | @item set remoteaddresssize @var{bits} |
d3e8051b | 15232 | @cindex address size for remote targets |
9c16f35a EZ |
15233 | @cindex bits in remote address |
15234 | Set the maximum size of address in a memory packet to the specified | |
15235 | number of bits. @value{GDBN} will mask off the address bits above | |
15236 | that number, when it passes addresses to the remote target. The | |
15237 | default value is the number of bits in the target's address. | |
15238 | ||
15239 | @item show remoteaddresssize | |
15240 | Show the current value of remote address size in bits. | |
15241 | ||
15242 | @item set remotebaud @var{n} | |
15243 | @cindex baud rate for remote targets | |
15244 | Set the baud rate for the remote serial I/O to @var{n} baud. The | |
15245 | value is used to set the speed of the serial port used for debugging | |
15246 | remote targets. | |
15247 | ||
15248 | @item show remotebaud | |
15249 | Show the current speed of the remote connection. | |
15250 | ||
15251 | @item set remotebreak | |
15252 | @cindex interrupt remote programs | |
15253 | @cindex BREAK signal instead of Ctrl-C | |
9a6253be | 15254 | @anchor{set remotebreak} |
9c16f35a | 15255 | If set to on, @value{GDBN} sends a @code{BREAK} signal to the remote |
c8aa23ab | 15256 | when you type @kbd{Ctrl-c} to interrupt the program running |
9a7a1b36 | 15257 | on the remote. If set to off, @value{GDBN} sends the @samp{Ctrl-C} |
9c16f35a EZ |
15258 | character instead. The default is off, since most remote systems |
15259 | expect to see @samp{Ctrl-C} as the interrupt signal. | |
15260 | ||
15261 | @item show remotebreak | |
15262 | Show whether @value{GDBN} sends @code{BREAK} or @samp{Ctrl-C} to | |
15263 | interrupt the remote program. | |
15264 | ||
23776285 MR |
15265 | @item set remoteflow on |
15266 | @itemx set remoteflow off | |
15267 | @kindex set remoteflow | |
15268 | Enable or disable hardware flow control (@code{RTS}/@code{CTS}) | |
15269 | on the serial port used to communicate to the remote target. | |
15270 | ||
15271 | @item show remoteflow | |
15272 | @kindex show remoteflow | |
15273 | Show the current setting of hardware flow control. | |
15274 | ||
9c16f35a EZ |
15275 | @item set remotelogbase @var{base} |
15276 | Set the base (a.k.a.@: radix) of logging serial protocol | |
15277 | communications to @var{base}. Supported values of @var{base} are: | |
15278 | @code{ascii}, @code{octal}, and @code{hex}. The default is | |
15279 | @code{ascii}. | |
15280 | ||
15281 | @item show remotelogbase | |
15282 | Show the current setting of the radix for logging remote serial | |
15283 | protocol. | |
15284 | ||
15285 | @item set remotelogfile @var{file} | |
15286 | @cindex record serial communications on file | |
15287 | Record remote serial communications on the named @var{file}. The | |
15288 | default is not to record at all. | |
15289 | ||
15290 | @item show remotelogfile. | |
15291 | Show the current setting of the file name on which to record the | |
15292 | serial communications. | |
15293 | ||
15294 | @item set remotetimeout @var{num} | |
15295 | @cindex timeout for serial communications | |
15296 | @cindex remote timeout | |
15297 | Set the timeout limit to wait for the remote target to respond to | |
15298 | @var{num} seconds. The default is 2 seconds. | |
15299 | ||
15300 | @item show remotetimeout | |
15301 | Show the current number of seconds to wait for the remote target | |
15302 | responses. | |
15303 | ||
15304 | @cindex limit hardware breakpoints and watchpoints | |
15305 | @cindex remote target, limit break- and watchpoints | |
501eef12 AC |
15306 | @anchor{set remote hardware-watchpoint-limit} |
15307 | @anchor{set remote hardware-breakpoint-limit} | |
15308 | @item set remote hardware-watchpoint-limit @var{limit} | |
15309 | @itemx set remote hardware-breakpoint-limit @var{limit} | |
15310 | Restrict @value{GDBN} to using @var{limit} remote hardware breakpoint or | |
15311 | watchpoints. A limit of -1, the default, is treated as unlimited. | |
2d717e4f DJ |
15312 | |
15313 | @item set remote exec-file @var{filename} | |
15314 | @itemx show remote exec-file | |
15315 | @anchor{set remote exec-file} | |
15316 | @cindex executable file, for remote target | |
15317 | Select the file used for @code{run} with @code{target | |
15318 | extended-remote}. This should be set to a filename valid on the | |
15319 | target system. If it is not set, the target will use a default | |
15320 | filename (e.g.@: the last program run). | |
84603566 | 15321 | |
9a7071a8 JB |
15322 | @item set remote interrupt-sequence |
15323 | @cindex interrupt remote programs | |
15324 | @cindex select Ctrl-C, BREAK or BREAK-g | |
15325 | Allow the user to select one of @samp{Ctrl-C}, a @code{BREAK} or | |
15326 | @samp{BREAK-g} as the | |
15327 | sequence to the remote target in order to interrupt the execution. | |
15328 | @samp{Ctrl-C} is a default. Some system prefers @code{BREAK} which | |
15329 | is high level of serial line for some certain time. | |
15330 | Linux kernel prefers @samp{BREAK-g}, a.k.a Magic SysRq g. | |
15331 | It is @code{BREAK} signal followed by character @code{g}. | |
15332 | ||
15333 | @item show interrupt-sequence | |
15334 | Show which of @samp{Ctrl-C}, @code{BREAK} or @code{BREAK-g} | |
15335 | is sent by @value{GDBN} to interrupt the remote program. | |
15336 | @code{BREAK-g} is BREAK signal followed by @code{g} and | |
15337 | also known as Magic SysRq g. | |
15338 | ||
15339 | @item set remote interrupt-on-connect | |
15340 | @cindex send interrupt-sequence on start | |
15341 | Specify whether interrupt-sequence is sent to remote target when | |
15342 | @value{GDBN} connects to it. This is mostly needed when you debug | |
15343 | Linux kernel. Linux kernel expects @code{BREAK} followed by @code{g} | |
15344 | which is known as Magic SysRq g in order to connect @value{GDBN}. | |
15345 | ||
15346 | @item show interrupt-on-connect | |
15347 | Show whether interrupt-sequence is sent | |
15348 | to remote target when @value{GDBN} connects to it. | |
15349 | ||
84603566 SL |
15350 | @kindex set tcp |
15351 | @kindex show tcp | |
15352 | @item set tcp auto-retry on | |
15353 | @cindex auto-retry, for remote TCP target | |
15354 | Enable auto-retry for remote TCP connections. This is useful if the remote | |
15355 | debugging agent is launched in parallel with @value{GDBN}; there is a race | |
15356 | condition because the agent may not become ready to accept the connection | |
15357 | before @value{GDBN} attempts to connect. When auto-retry is | |
15358 | enabled, if the initial attempt to connect fails, @value{GDBN} reattempts | |
15359 | to establish the connection using the timeout specified by | |
15360 | @code{set tcp connect-timeout}. | |
15361 | ||
15362 | @item set tcp auto-retry off | |
15363 | Do not auto-retry failed TCP connections. | |
15364 | ||
15365 | @item show tcp auto-retry | |
15366 | Show the current auto-retry setting. | |
15367 | ||
15368 | @item set tcp connect-timeout @var{seconds} | |
15369 | @cindex connection timeout, for remote TCP target | |
15370 | @cindex timeout, for remote target connection | |
15371 | Set the timeout for establishing a TCP connection to the remote target to | |
15372 | @var{seconds}. The timeout affects both polling to retry failed connections | |
15373 | (enabled by @code{set tcp auto-retry on}) and waiting for connections | |
15374 | that are merely slow to complete, and represents an approximate cumulative | |
15375 | value. | |
15376 | ||
15377 | @item show tcp connect-timeout | |
15378 | Show the current connection timeout setting. | |
501eef12 AC |
15379 | @end table |
15380 | ||
427c3a89 DJ |
15381 | @cindex remote packets, enabling and disabling |
15382 | The @value{GDBN} remote protocol autodetects the packets supported by | |
15383 | your debugging stub. If you need to override the autodetection, you | |
15384 | can use these commands to enable or disable individual packets. Each | |
15385 | packet can be set to @samp{on} (the remote target supports this | |
15386 | packet), @samp{off} (the remote target does not support this packet), | |
15387 | or @samp{auto} (detect remote target support for this packet). They | |
15388 | all default to @samp{auto}. For more information about each packet, | |
15389 | see @ref{Remote Protocol}. | |
15390 | ||
15391 | During normal use, you should not have to use any of these commands. | |
15392 | If you do, that may be a bug in your remote debugging stub, or a bug | |
15393 | in @value{GDBN}. You may want to report the problem to the | |
15394 | @value{GDBN} developers. | |
15395 | ||
cfa9d6d9 DJ |
15396 | For each packet @var{name}, the command to enable or disable the |
15397 | packet is @code{set remote @var{name}-packet}. The available settings | |
15398 | are: | |
427c3a89 | 15399 | |
cfa9d6d9 | 15400 | @multitable @columnfractions 0.28 0.32 0.25 |
427c3a89 DJ |
15401 | @item Command Name |
15402 | @tab Remote Packet | |
15403 | @tab Related Features | |
15404 | ||
cfa9d6d9 | 15405 | @item @code{fetch-register} |
427c3a89 DJ |
15406 | @tab @code{p} |
15407 | @tab @code{info registers} | |
15408 | ||
cfa9d6d9 | 15409 | @item @code{set-register} |
427c3a89 DJ |
15410 | @tab @code{P} |
15411 | @tab @code{set} | |
15412 | ||
cfa9d6d9 | 15413 | @item @code{binary-download} |
427c3a89 DJ |
15414 | @tab @code{X} |
15415 | @tab @code{load}, @code{set} | |
15416 | ||
cfa9d6d9 | 15417 | @item @code{read-aux-vector} |
427c3a89 DJ |
15418 | @tab @code{qXfer:auxv:read} |
15419 | @tab @code{info auxv} | |
15420 | ||
cfa9d6d9 | 15421 | @item @code{symbol-lookup} |
427c3a89 DJ |
15422 | @tab @code{qSymbol} |
15423 | @tab Detecting multiple threads | |
15424 | ||
2d717e4f DJ |
15425 | @item @code{attach} |
15426 | @tab @code{vAttach} | |
15427 | @tab @code{attach} | |
15428 | ||
cfa9d6d9 | 15429 | @item @code{verbose-resume} |
427c3a89 DJ |
15430 | @tab @code{vCont} |
15431 | @tab Stepping or resuming multiple threads | |
15432 | ||
2d717e4f DJ |
15433 | @item @code{run} |
15434 | @tab @code{vRun} | |
15435 | @tab @code{run} | |
15436 | ||
cfa9d6d9 | 15437 | @item @code{software-breakpoint} |
427c3a89 DJ |
15438 | @tab @code{Z0} |
15439 | @tab @code{break} | |
15440 | ||
cfa9d6d9 | 15441 | @item @code{hardware-breakpoint} |
427c3a89 DJ |
15442 | @tab @code{Z1} |
15443 | @tab @code{hbreak} | |
15444 | ||
cfa9d6d9 | 15445 | @item @code{write-watchpoint} |
427c3a89 DJ |
15446 | @tab @code{Z2} |
15447 | @tab @code{watch} | |
15448 | ||
cfa9d6d9 | 15449 | @item @code{read-watchpoint} |
427c3a89 DJ |
15450 | @tab @code{Z3} |
15451 | @tab @code{rwatch} | |
15452 | ||
cfa9d6d9 | 15453 | @item @code{access-watchpoint} |
427c3a89 DJ |
15454 | @tab @code{Z4} |
15455 | @tab @code{awatch} | |
15456 | ||
cfa9d6d9 DJ |
15457 | @item @code{target-features} |
15458 | @tab @code{qXfer:features:read} | |
15459 | @tab @code{set architecture} | |
15460 | ||
15461 | @item @code{library-info} | |
15462 | @tab @code{qXfer:libraries:read} | |
15463 | @tab @code{info sharedlibrary} | |
15464 | ||
15465 | @item @code{memory-map} | |
15466 | @tab @code{qXfer:memory-map:read} | |
15467 | @tab @code{info mem} | |
15468 | ||
15469 | @item @code{read-spu-object} | |
15470 | @tab @code{qXfer:spu:read} | |
15471 | @tab @code{info spu} | |
15472 | ||
15473 | @item @code{write-spu-object} | |
15474 | @tab @code{qXfer:spu:write} | |
15475 | @tab @code{info spu} | |
15476 | ||
4aa995e1 PA |
15477 | @item @code{read-siginfo-object} |
15478 | @tab @code{qXfer:siginfo:read} | |
15479 | @tab @code{print $_siginfo} | |
15480 | ||
15481 | @item @code{write-siginfo-object} | |
15482 | @tab @code{qXfer:siginfo:write} | |
15483 | @tab @code{set $_siginfo} | |
15484 | ||
cfa9d6d9 | 15485 | @item @code{get-thread-local-@*storage-address} |
427c3a89 DJ |
15486 | @tab @code{qGetTLSAddr} |
15487 | @tab Displaying @code{__thread} variables | |
15488 | ||
08388c79 DE |
15489 | @item @code{search-memory} |
15490 | @tab @code{qSearch:memory} | |
15491 | @tab @code{find} | |
15492 | ||
427c3a89 DJ |
15493 | @item @code{supported-packets} |
15494 | @tab @code{qSupported} | |
15495 | @tab Remote communications parameters | |
15496 | ||
cfa9d6d9 | 15497 | @item @code{pass-signals} |
89be2091 DJ |
15498 | @tab @code{QPassSignals} |
15499 | @tab @code{handle @var{signal}} | |
15500 | ||
a6b151f1 DJ |
15501 | @item @code{hostio-close-packet} |
15502 | @tab @code{vFile:close} | |
15503 | @tab @code{remote get}, @code{remote put} | |
15504 | ||
15505 | @item @code{hostio-open-packet} | |
15506 | @tab @code{vFile:open} | |
15507 | @tab @code{remote get}, @code{remote put} | |
15508 | ||
15509 | @item @code{hostio-pread-packet} | |
15510 | @tab @code{vFile:pread} | |
15511 | @tab @code{remote get}, @code{remote put} | |
15512 | ||
15513 | @item @code{hostio-pwrite-packet} | |
15514 | @tab @code{vFile:pwrite} | |
15515 | @tab @code{remote get}, @code{remote put} | |
15516 | ||
15517 | @item @code{hostio-unlink-packet} | |
15518 | @tab @code{vFile:unlink} | |
15519 | @tab @code{remote delete} | |
a6f3e723 SL |
15520 | |
15521 | @item @code{noack-packet} | |
15522 | @tab @code{QStartNoAckMode} | |
15523 | @tab Packet acknowledgment | |
07e059b5 VP |
15524 | |
15525 | @item @code{osdata} | |
15526 | @tab @code{qXfer:osdata:read} | |
15527 | @tab @code{info os} | |
0b16c5cf PA |
15528 | |
15529 | @item @code{query-attached} | |
15530 | @tab @code{qAttached} | |
15531 | @tab Querying remote process attach state. | |
427c3a89 DJ |
15532 | @end multitable |
15533 | ||
79a6e687 BW |
15534 | @node Remote Stub |
15535 | @section Implementing a Remote Stub | |
7a292a7a | 15536 | |
8e04817f AC |
15537 | @cindex debugging stub, example |
15538 | @cindex remote stub, example | |
15539 | @cindex stub example, remote debugging | |
15540 | The stub files provided with @value{GDBN} implement the target side of the | |
15541 | communication protocol, and the @value{GDBN} side is implemented in the | |
15542 | @value{GDBN} source file @file{remote.c}. Normally, you can simply allow | |
15543 | these subroutines to communicate, and ignore the details. (If you're | |
15544 | implementing your own stub file, you can still ignore the details: start | |
15545 | with one of the existing stub files. @file{sparc-stub.c} is the best | |
15546 | organized, and therefore the easiest to read.) | |
15547 | ||
104c1213 JM |
15548 | @cindex remote serial debugging, overview |
15549 | To debug a program running on another machine (the debugging | |
15550 | @dfn{target} machine), you must first arrange for all the usual | |
15551 | prerequisites for the program to run by itself. For example, for a C | |
15552 | program, you need: | |
c906108c | 15553 | |
104c1213 JM |
15554 | @enumerate |
15555 | @item | |
15556 | A startup routine to set up the C runtime environment; these usually | |
15557 | have a name like @file{crt0}. The startup routine may be supplied by | |
15558 | your hardware supplier, or you may have to write your own. | |
96baa820 | 15559 | |
5d161b24 | 15560 | @item |
d4f3574e | 15561 | A C subroutine library to support your program's |
104c1213 | 15562 | subroutine calls, notably managing input and output. |
96baa820 | 15563 | |
104c1213 JM |
15564 | @item |
15565 | A way of getting your program to the other machine---for example, a | |
15566 | download program. These are often supplied by the hardware | |
15567 | manufacturer, but you may have to write your own from hardware | |
15568 | documentation. | |
15569 | @end enumerate | |
96baa820 | 15570 | |
104c1213 JM |
15571 | The next step is to arrange for your program to use a serial port to |
15572 | communicate with the machine where @value{GDBN} is running (the @dfn{host} | |
15573 | machine). In general terms, the scheme looks like this: | |
96baa820 | 15574 | |
104c1213 JM |
15575 | @table @emph |
15576 | @item On the host, | |
15577 | @value{GDBN} already understands how to use this protocol; when everything | |
15578 | else is set up, you can simply use the @samp{target remote} command | |
15579 | (@pxref{Targets,,Specifying a Debugging Target}). | |
15580 | ||
15581 | @item On the target, | |
15582 | you must link with your program a few special-purpose subroutines that | |
15583 | implement the @value{GDBN} remote serial protocol. The file containing these | |
15584 | subroutines is called a @dfn{debugging stub}. | |
15585 | ||
15586 | On certain remote targets, you can use an auxiliary program | |
15587 | @code{gdbserver} instead of linking a stub into your program. | |
79a6e687 | 15588 | @xref{Server,,Using the @code{gdbserver} Program}, for details. |
104c1213 | 15589 | @end table |
96baa820 | 15590 | |
104c1213 JM |
15591 | The debugging stub is specific to the architecture of the remote |
15592 | machine; for example, use @file{sparc-stub.c} to debug programs on | |
15593 | @sc{sparc} boards. | |
96baa820 | 15594 | |
104c1213 JM |
15595 | @cindex remote serial stub list |
15596 | These working remote stubs are distributed with @value{GDBN}: | |
96baa820 | 15597 | |
104c1213 JM |
15598 | @table @code |
15599 | ||
15600 | @item i386-stub.c | |
41afff9a | 15601 | @cindex @file{i386-stub.c} |
104c1213 JM |
15602 | @cindex Intel |
15603 | @cindex i386 | |
15604 | For Intel 386 and compatible architectures. | |
15605 | ||
15606 | @item m68k-stub.c | |
41afff9a | 15607 | @cindex @file{m68k-stub.c} |
104c1213 JM |
15608 | @cindex Motorola 680x0 |
15609 | @cindex m680x0 | |
15610 | For Motorola 680x0 architectures. | |
15611 | ||
15612 | @item sh-stub.c | |
41afff9a | 15613 | @cindex @file{sh-stub.c} |
172c2a43 | 15614 | @cindex Renesas |
104c1213 | 15615 | @cindex SH |
172c2a43 | 15616 | For Renesas SH architectures. |
104c1213 JM |
15617 | |
15618 | @item sparc-stub.c | |
41afff9a | 15619 | @cindex @file{sparc-stub.c} |
104c1213 JM |
15620 | @cindex Sparc |
15621 | For @sc{sparc} architectures. | |
15622 | ||
15623 | @item sparcl-stub.c | |
41afff9a | 15624 | @cindex @file{sparcl-stub.c} |
104c1213 JM |
15625 | @cindex Fujitsu |
15626 | @cindex SparcLite | |
15627 | For Fujitsu @sc{sparclite} architectures. | |
15628 | ||
15629 | @end table | |
15630 | ||
15631 | The @file{README} file in the @value{GDBN} distribution may list other | |
15632 | recently added stubs. | |
15633 | ||
15634 | @menu | |
15635 | * Stub Contents:: What the stub can do for you | |
15636 | * Bootstrapping:: What you must do for the stub | |
15637 | * Debug Session:: Putting it all together | |
104c1213 JM |
15638 | @end menu |
15639 | ||
6d2ebf8b | 15640 | @node Stub Contents |
79a6e687 | 15641 | @subsection What the Stub Can Do for You |
104c1213 JM |
15642 | |
15643 | @cindex remote serial stub | |
15644 | The debugging stub for your architecture supplies these three | |
15645 | subroutines: | |
15646 | ||
15647 | @table @code | |
15648 | @item set_debug_traps | |
4644b6e3 | 15649 | @findex set_debug_traps |
104c1213 JM |
15650 | @cindex remote serial stub, initialization |
15651 | This routine arranges for @code{handle_exception} to run when your | |
15652 | program stops. You must call this subroutine explicitly near the | |
15653 | beginning of your program. | |
15654 | ||
15655 | @item handle_exception | |
4644b6e3 | 15656 | @findex handle_exception |
104c1213 JM |
15657 | @cindex remote serial stub, main routine |
15658 | This is the central workhorse, but your program never calls it | |
15659 | explicitly---the setup code arranges for @code{handle_exception} to | |
15660 | run when a trap is triggered. | |
15661 | ||
15662 | @code{handle_exception} takes control when your program stops during | |
15663 | execution (for example, on a breakpoint), and mediates communications | |
15664 | with @value{GDBN} on the host machine. This is where the communications | |
15665 | protocol is implemented; @code{handle_exception} acts as the @value{GDBN} | |
d4f3574e | 15666 | representative on the target machine. It begins by sending summary |
104c1213 JM |
15667 | information on the state of your program, then continues to execute, |
15668 | retrieving and transmitting any information @value{GDBN} needs, until you | |
15669 | execute a @value{GDBN} command that makes your program resume; at that point, | |
15670 | @code{handle_exception} returns control to your own code on the target | |
5d161b24 | 15671 | machine. |
104c1213 JM |
15672 | |
15673 | @item breakpoint | |
15674 | @cindex @code{breakpoint} subroutine, remote | |
15675 | Use this auxiliary subroutine to make your program contain a | |
15676 | breakpoint. Depending on the particular situation, this may be the only | |
15677 | way for @value{GDBN} to get control. For instance, if your target | |
15678 | machine has some sort of interrupt button, you won't need to call this; | |
15679 | pressing the interrupt button transfers control to | |
15680 | @code{handle_exception}---in effect, to @value{GDBN}. On some machines, | |
15681 | simply receiving characters on the serial port may also trigger a trap; | |
15682 | again, in that situation, you don't need to call @code{breakpoint} from | |
15683 | your own program---simply running @samp{target remote} from the host | |
5d161b24 | 15684 | @value{GDBN} session gets control. |
104c1213 JM |
15685 | |
15686 | Call @code{breakpoint} if none of these is true, or if you simply want | |
15687 | to make certain your program stops at a predetermined point for the | |
15688 | start of your debugging session. | |
15689 | @end table | |
15690 | ||
6d2ebf8b | 15691 | @node Bootstrapping |
79a6e687 | 15692 | @subsection What You Must Do for the Stub |
104c1213 JM |
15693 | |
15694 | @cindex remote stub, support routines | |
15695 | The debugging stubs that come with @value{GDBN} are set up for a particular | |
15696 | chip architecture, but they have no information about the rest of your | |
15697 | debugging target machine. | |
15698 | ||
15699 | First of all you need to tell the stub how to communicate with the | |
15700 | serial port. | |
15701 | ||
15702 | @table @code | |
15703 | @item int getDebugChar() | |
4644b6e3 | 15704 | @findex getDebugChar |
104c1213 JM |
15705 | Write this subroutine to read a single character from the serial port. |
15706 | It may be identical to @code{getchar} for your target system; a | |
15707 | different name is used to allow you to distinguish the two if you wish. | |
15708 | ||
15709 | @item void putDebugChar(int) | |
4644b6e3 | 15710 | @findex putDebugChar |
104c1213 | 15711 | Write this subroutine to write a single character to the serial port. |
5d161b24 | 15712 | It may be identical to @code{putchar} for your target system; a |
104c1213 JM |
15713 | different name is used to allow you to distinguish the two if you wish. |
15714 | @end table | |
15715 | ||
15716 | @cindex control C, and remote debugging | |
15717 | @cindex interrupting remote targets | |
15718 | If you want @value{GDBN} to be able to stop your program while it is | |
15719 | running, you need to use an interrupt-driven serial driver, and arrange | |
15720 | for it to stop when it receives a @code{^C} (@samp{\003}, the control-C | |
15721 | character). That is the character which @value{GDBN} uses to tell the | |
15722 | remote system to stop. | |
15723 | ||
15724 | Getting the debugging target to return the proper status to @value{GDBN} | |
15725 | probably requires changes to the standard stub; one quick and dirty way | |
15726 | is to just execute a breakpoint instruction (the ``dirty'' part is that | |
15727 | @value{GDBN} reports a @code{SIGTRAP} instead of a @code{SIGINT}). | |
15728 | ||
15729 | Other routines you need to supply are: | |
15730 | ||
15731 | @table @code | |
15732 | @item void exceptionHandler (int @var{exception_number}, void *@var{exception_address}) | |
4644b6e3 | 15733 | @findex exceptionHandler |
104c1213 JM |
15734 | Write this function to install @var{exception_address} in the exception |
15735 | handling tables. You need to do this because the stub does not have any | |
15736 | way of knowing what the exception handling tables on your target system | |
15737 | are like (for example, the processor's table might be in @sc{rom}, | |
15738 | containing entries which point to a table in @sc{ram}). | |
15739 | @var{exception_number} is the exception number which should be changed; | |
15740 | its meaning is architecture-dependent (for example, different numbers | |
15741 | might represent divide by zero, misaligned access, etc). When this | |
15742 | exception occurs, control should be transferred directly to | |
15743 | @var{exception_address}, and the processor state (stack, registers, | |
15744 | and so on) should be just as it is when a processor exception occurs. So if | |
15745 | you want to use a jump instruction to reach @var{exception_address}, it | |
15746 | should be a simple jump, not a jump to subroutine. | |
15747 | ||
15748 | For the 386, @var{exception_address} should be installed as an interrupt | |
15749 | gate so that interrupts are masked while the handler runs. The gate | |
15750 | should be at privilege level 0 (the most privileged level). The | |
15751 | @sc{sparc} and 68k stubs are able to mask interrupts themselves without | |
15752 | help from @code{exceptionHandler}. | |
15753 | ||
15754 | @item void flush_i_cache() | |
4644b6e3 | 15755 | @findex flush_i_cache |
d4f3574e | 15756 | On @sc{sparc} and @sc{sparclite} only, write this subroutine to flush the |
104c1213 JM |
15757 | instruction cache, if any, on your target machine. If there is no |
15758 | instruction cache, this subroutine may be a no-op. | |
15759 | ||
15760 | On target machines that have instruction caches, @value{GDBN} requires this | |
15761 | function to make certain that the state of your program is stable. | |
15762 | @end table | |
15763 | ||
15764 | @noindent | |
15765 | You must also make sure this library routine is available: | |
15766 | ||
15767 | @table @code | |
15768 | @item void *memset(void *, int, int) | |
4644b6e3 | 15769 | @findex memset |
104c1213 JM |
15770 | This is the standard library function @code{memset} that sets an area of |
15771 | memory to a known value. If you have one of the free versions of | |
15772 | @code{libc.a}, @code{memset} can be found there; otherwise, you must | |
15773 | either obtain it from your hardware manufacturer, or write your own. | |
15774 | @end table | |
15775 | ||
15776 | If you do not use the GNU C compiler, you may need other standard | |
15777 | library subroutines as well; this varies from one stub to another, | |
15778 | but in general the stubs are likely to use any of the common library | |
e22ea452 | 15779 | subroutines which @code{@value{NGCC}} generates as inline code. |
104c1213 JM |
15780 | |
15781 | ||
6d2ebf8b | 15782 | @node Debug Session |
79a6e687 | 15783 | @subsection Putting it All Together |
104c1213 JM |
15784 | |
15785 | @cindex remote serial debugging summary | |
15786 | In summary, when your program is ready to debug, you must follow these | |
15787 | steps. | |
15788 | ||
15789 | @enumerate | |
15790 | @item | |
6d2ebf8b | 15791 | Make sure you have defined the supporting low-level routines |
79a6e687 | 15792 | (@pxref{Bootstrapping,,What You Must Do for the Stub}): |
104c1213 JM |
15793 | @display |
15794 | @code{getDebugChar}, @code{putDebugChar}, | |
15795 | @code{flush_i_cache}, @code{memset}, @code{exceptionHandler}. | |
15796 | @end display | |
15797 | ||
15798 | @item | |
15799 | Insert these lines near the top of your program: | |
15800 | ||
474c8240 | 15801 | @smallexample |
104c1213 JM |
15802 | set_debug_traps(); |
15803 | breakpoint(); | |
474c8240 | 15804 | @end smallexample |
104c1213 JM |
15805 | |
15806 | @item | |
15807 | For the 680x0 stub only, you need to provide a variable called | |
15808 | @code{exceptionHook}. Normally you just use: | |
15809 | ||
474c8240 | 15810 | @smallexample |
104c1213 | 15811 | void (*exceptionHook)() = 0; |
474c8240 | 15812 | @end smallexample |
104c1213 | 15813 | |
d4f3574e | 15814 | @noindent |
104c1213 | 15815 | but if before calling @code{set_debug_traps}, you set it to point to a |
598ca718 | 15816 | function in your program, that function is called when |
104c1213 JM |
15817 | @code{@value{GDBN}} continues after stopping on a trap (for example, bus |
15818 | error). The function indicated by @code{exceptionHook} is called with | |
15819 | one parameter: an @code{int} which is the exception number. | |
15820 | ||
15821 | @item | |
15822 | Compile and link together: your program, the @value{GDBN} debugging stub for | |
15823 | your target architecture, and the supporting subroutines. | |
15824 | ||
15825 | @item | |
15826 | Make sure you have a serial connection between your target machine and | |
15827 | the @value{GDBN} host, and identify the serial port on the host. | |
15828 | ||
15829 | @item | |
15830 | @c The "remote" target now provides a `load' command, so we should | |
15831 | @c document that. FIXME. | |
15832 | Download your program to your target machine (or get it there by | |
15833 | whatever means the manufacturer provides), and start it. | |
15834 | ||
15835 | @item | |
07f31aa6 | 15836 | Start @value{GDBN} on the host, and connect to the target |
79a6e687 | 15837 | (@pxref{Connecting,,Connecting to a Remote Target}). |
9db8d71f | 15838 | |
104c1213 JM |
15839 | @end enumerate |
15840 | ||
8e04817f AC |
15841 | @node Configurations |
15842 | @chapter Configuration-Specific Information | |
104c1213 | 15843 | |
8e04817f AC |
15844 | While nearly all @value{GDBN} commands are available for all native and |
15845 | cross versions of the debugger, there are some exceptions. This chapter | |
15846 | describes things that are only available in certain configurations. | |
104c1213 | 15847 | |
8e04817f AC |
15848 | There are three major categories of configurations: native |
15849 | configurations, where the host and target are the same, embedded | |
15850 | operating system configurations, which are usually the same for several | |
15851 | different processor architectures, and bare embedded processors, which | |
15852 | are quite different from each other. | |
104c1213 | 15853 | |
8e04817f AC |
15854 | @menu |
15855 | * Native:: | |
15856 | * Embedded OS:: | |
15857 | * Embedded Processors:: | |
15858 | * Architectures:: | |
15859 | @end menu | |
104c1213 | 15860 | |
8e04817f AC |
15861 | @node Native |
15862 | @section Native | |
104c1213 | 15863 | |
8e04817f AC |
15864 | This section describes details specific to particular native |
15865 | configurations. | |
6cf7e474 | 15866 | |
8e04817f AC |
15867 | @menu |
15868 | * HP-UX:: HP-UX | |
7561d450 | 15869 | * BSD libkvm Interface:: Debugging BSD kernel memory images |
8e04817f AC |
15870 | * SVR4 Process Information:: SVR4 process information |
15871 | * DJGPP Native:: Features specific to the DJGPP port | |
78c47bea | 15872 | * Cygwin Native:: Features specific to the Cygwin port |
14d6dd68 | 15873 | * Hurd Native:: Features specific to @sc{gnu} Hurd |
a64548ea | 15874 | * Neutrino:: Features specific to QNX Neutrino |
a80b95ba | 15875 | * Darwin:: Features specific to Darwin |
8e04817f | 15876 | @end menu |
6cf7e474 | 15877 | |
8e04817f AC |
15878 | @node HP-UX |
15879 | @subsection HP-UX | |
104c1213 | 15880 | |
8e04817f AC |
15881 | On HP-UX systems, if you refer to a function or variable name that |
15882 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
15883 | name first, before it searches for a convenience variable. | |
104c1213 | 15884 | |
9c16f35a | 15885 | |
7561d450 MK |
15886 | @node BSD libkvm Interface |
15887 | @subsection BSD libkvm Interface | |
15888 | ||
15889 | @cindex libkvm | |
15890 | @cindex kernel memory image | |
15891 | @cindex kernel crash dump | |
15892 | ||
15893 | BSD-derived systems (FreeBSD/NetBSD/OpenBSD) have a kernel memory | |
15894 | interface that provides a uniform interface for accessing kernel virtual | |
15895 | memory images, including live systems and crash dumps. @value{GDBN} | |
15896 | uses this interface to allow you to debug live kernels and kernel crash | |
15897 | dumps on many native BSD configurations. This is implemented as a | |
15898 | special @code{kvm} debugging target. For debugging a live system, load | |
15899 | the currently running kernel into @value{GDBN} and connect to the | |
15900 | @code{kvm} target: | |
15901 | ||
15902 | @smallexample | |
15903 | (@value{GDBP}) @b{target kvm} | |
15904 | @end smallexample | |
15905 | ||
15906 | For debugging crash dumps, provide the file name of the crash dump as an | |
15907 | argument: | |
15908 | ||
15909 | @smallexample | |
15910 | (@value{GDBP}) @b{target kvm /var/crash/bsd.0} | |
15911 | @end smallexample | |
15912 | ||
15913 | Once connected to the @code{kvm} target, the following commands are | |
15914 | available: | |
15915 | ||
15916 | @table @code | |
15917 | @kindex kvm | |
15918 | @item kvm pcb | |
721c2651 | 15919 | Set current context from the @dfn{Process Control Block} (PCB) address. |
7561d450 MK |
15920 | |
15921 | @item kvm proc | |
15922 | Set current context from proc address. This command isn't available on | |
15923 | modern FreeBSD systems. | |
15924 | @end table | |
15925 | ||
8e04817f | 15926 | @node SVR4 Process Information |
79a6e687 | 15927 | @subsection SVR4 Process Information |
60bf7e09 EZ |
15928 | @cindex /proc |
15929 | @cindex examine process image | |
15930 | @cindex process info via @file{/proc} | |
104c1213 | 15931 | |
60bf7e09 EZ |
15932 | Many versions of SVR4 and compatible systems provide a facility called |
15933 | @samp{/proc} that can be used to examine the image of a running | |
15934 | process using file-system subroutines. If @value{GDBN} is configured | |
15935 | for an operating system with this facility, the command @code{info | |
15936 | proc} is available to report information about the process running | |
15937 | your program, or about any process running on your system. @code{info | |
15938 | proc} works only on SVR4 systems that include the @code{procfs} code. | |
15939 | This includes, as of this writing, @sc{gnu}/Linux, OSF/1 (Digital | |
15940 | Unix), Solaris, Irix, and Unixware, but not HP-UX, for example. | |
104c1213 | 15941 | |
8e04817f AC |
15942 | @table @code |
15943 | @kindex info proc | |
60bf7e09 | 15944 | @cindex process ID |
8e04817f | 15945 | @item info proc |
60bf7e09 EZ |
15946 | @itemx info proc @var{process-id} |
15947 | Summarize available information about any running process. If a | |
15948 | process ID is specified by @var{process-id}, display information about | |
15949 | that process; otherwise display information about the program being | |
15950 | debugged. The summary includes the debugged process ID, the command | |
15951 | line used to invoke it, its current working directory, and its | |
15952 | executable file's absolute file name. | |
15953 | ||
15954 | On some systems, @var{process-id} can be of the form | |
15955 | @samp{[@var{pid}]/@var{tid}} which specifies a certain thread ID | |
15956 | within a process. If the optional @var{pid} part is missing, it means | |
15957 | a thread from the process being debugged (the leading @samp{/} still | |
15958 | needs to be present, or else @value{GDBN} will interpret the number as | |
15959 | a process ID rather than a thread ID). | |
6cf7e474 | 15960 | |
8e04817f | 15961 | @item info proc mappings |
60bf7e09 EZ |
15962 | @cindex memory address space mappings |
15963 | Report the memory address space ranges accessible in the program, with | |
15964 | information on whether the process has read, write, or execute access | |
15965 | rights to each range. On @sc{gnu}/Linux systems, each memory range | |
15966 | includes the object file which is mapped to that range, instead of the | |
15967 | memory access rights to that range. | |
15968 | ||
15969 | @item info proc stat | |
15970 | @itemx info proc status | |
15971 | @cindex process detailed status information | |
15972 | These subcommands are specific to @sc{gnu}/Linux systems. They show | |
15973 | the process-related information, including the user ID and group ID; | |
15974 | how many threads are there in the process; its virtual memory usage; | |
15975 | the signals that are pending, blocked, and ignored; its TTY; its | |
15976 | consumption of system and user time; its stack size; its @samp{nice} | |
2eecc4ab | 15977 | value; etc. For more information, see the @samp{proc} man page |
60bf7e09 EZ |
15978 | (type @kbd{man 5 proc} from your shell prompt). |
15979 | ||
15980 | @item info proc all | |
15981 | Show all the information about the process described under all of the | |
15982 | above @code{info proc} subcommands. | |
15983 | ||
8e04817f AC |
15984 | @ignore |
15985 | @comment These sub-options of 'info proc' were not included when | |
15986 | @comment procfs.c was re-written. Keep their descriptions around | |
15987 | @comment against the day when someone finds the time to put them back in. | |
15988 | @kindex info proc times | |
15989 | @item info proc times | |
15990 | Starting time, user CPU time, and system CPU time for your program and | |
15991 | its children. | |
6cf7e474 | 15992 | |
8e04817f AC |
15993 | @kindex info proc id |
15994 | @item info proc id | |
15995 | Report on the process IDs related to your program: its own process ID, | |
15996 | the ID of its parent, the process group ID, and the session ID. | |
8e04817f | 15997 | @end ignore |
721c2651 EZ |
15998 | |
15999 | @item set procfs-trace | |
16000 | @kindex set procfs-trace | |
16001 | @cindex @code{procfs} API calls | |
16002 | This command enables and disables tracing of @code{procfs} API calls. | |
16003 | ||
16004 | @item show procfs-trace | |
16005 | @kindex show procfs-trace | |
16006 | Show the current state of @code{procfs} API call tracing. | |
16007 | ||
16008 | @item set procfs-file @var{file} | |
16009 | @kindex set procfs-file | |
16010 | Tell @value{GDBN} to write @code{procfs} API trace to the named | |
16011 | @var{file}. @value{GDBN} appends the trace info to the previous | |
16012 | contents of the file. The default is to display the trace on the | |
16013 | standard output. | |
16014 | ||
16015 | @item show procfs-file | |
16016 | @kindex show procfs-file | |
16017 | Show the file to which @code{procfs} API trace is written. | |
16018 | ||
16019 | @item proc-trace-entry | |
16020 | @itemx proc-trace-exit | |
16021 | @itemx proc-untrace-entry | |
16022 | @itemx proc-untrace-exit | |
16023 | @kindex proc-trace-entry | |
16024 | @kindex proc-trace-exit | |
16025 | @kindex proc-untrace-entry | |
16026 | @kindex proc-untrace-exit | |
16027 | These commands enable and disable tracing of entries into and exits | |
16028 | from the @code{syscall} interface. | |
16029 | ||
16030 | @item info pidlist | |
16031 | @kindex info pidlist | |
16032 | @cindex process list, QNX Neutrino | |
16033 | For QNX Neutrino only, this command displays the list of all the | |
16034 | processes and all the threads within each process. | |
16035 | ||
16036 | @item info meminfo | |
16037 | @kindex info meminfo | |
16038 | @cindex mapinfo list, QNX Neutrino | |
16039 | For QNX Neutrino only, this command displays the list of all mapinfos. | |
8e04817f | 16040 | @end table |
104c1213 | 16041 | |
8e04817f AC |
16042 | @node DJGPP Native |
16043 | @subsection Features for Debugging @sc{djgpp} Programs | |
16044 | @cindex @sc{djgpp} debugging | |
16045 | @cindex native @sc{djgpp} debugging | |
16046 | @cindex MS-DOS-specific commands | |
104c1213 | 16047 | |
514c4d71 EZ |
16048 | @cindex DPMI |
16049 | @sc{djgpp} is a port of the @sc{gnu} development tools to MS-DOS and | |
8e04817f AC |
16050 | MS-Windows. @sc{djgpp} programs are 32-bit protected-mode programs |
16051 | that use the @dfn{DPMI} (DOS Protected-Mode Interface) API to run on | |
16052 | top of real-mode DOS systems and their emulations. | |
104c1213 | 16053 | |
8e04817f AC |
16054 | @value{GDBN} supports native debugging of @sc{djgpp} programs, and |
16055 | defines a few commands specific to the @sc{djgpp} port. This | |
16056 | subsection describes those commands. | |
104c1213 | 16057 | |
8e04817f AC |
16058 | @table @code |
16059 | @kindex info dos | |
16060 | @item info dos | |
16061 | This is a prefix of @sc{djgpp}-specific commands which print | |
16062 | information about the target system and important OS structures. | |
f1251bdd | 16063 | |
8e04817f AC |
16064 | @kindex sysinfo |
16065 | @cindex MS-DOS system info | |
16066 | @cindex free memory information (MS-DOS) | |
16067 | @item info dos sysinfo | |
16068 | This command displays assorted information about the underlying | |
16069 | platform: the CPU type and features, the OS version and flavor, the | |
16070 | DPMI version, and the available conventional and DPMI memory. | |
104c1213 | 16071 | |
8e04817f AC |
16072 | @cindex GDT |
16073 | @cindex LDT | |
16074 | @cindex IDT | |
16075 | @cindex segment descriptor tables | |
16076 | @cindex descriptor tables display | |
16077 | @item info dos gdt | |
16078 | @itemx info dos ldt | |
16079 | @itemx info dos idt | |
16080 | These 3 commands display entries from, respectively, Global, Local, | |
16081 | and Interrupt Descriptor Tables (GDT, LDT, and IDT). The descriptor | |
16082 | tables are data structures which store a descriptor for each segment | |
16083 | that is currently in use. The segment's selector is an index into a | |
16084 | descriptor table; the table entry for that index holds the | |
16085 | descriptor's base address and limit, and its attributes and access | |
16086 | rights. | |
104c1213 | 16087 | |
8e04817f AC |
16088 | A typical @sc{djgpp} program uses 3 segments: a code segment, a data |
16089 | segment (used for both data and the stack), and a DOS segment (which | |
16090 | allows access to DOS/BIOS data structures and absolute addresses in | |
16091 | conventional memory). However, the DPMI host will usually define | |
16092 | additional segments in order to support the DPMI environment. | |
d4f3574e | 16093 | |
8e04817f AC |
16094 | @cindex garbled pointers |
16095 | These commands allow to display entries from the descriptor tables. | |
16096 | Without an argument, all entries from the specified table are | |
16097 | displayed. An argument, which should be an integer expression, means | |
16098 | display a single entry whose index is given by the argument. For | |
16099 | example, here's a convenient way to display information about the | |
16100 | debugged program's data segment: | |
104c1213 | 16101 | |
8e04817f AC |
16102 | @smallexample |
16103 | @exdent @code{(@value{GDBP}) info dos ldt $ds} | |
16104 | @exdent @code{0x13f: base=0x11970000 limit=0x0009ffff 32-Bit Data (Read/Write, Exp-up)} | |
16105 | @end smallexample | |
104c1213 | 16106 | |
8e04817f AC |
16107 | @noindent |
16108 | This comes in handy when you want to see whether a pointer is outside | |
16109 | the data segment's limit (i.e.@: @dfn{garbled}). | |
104c1213 | 16110 | |
8e04817f AC |
16111 | @cindex page tables display (MS-DOS) |
16112 | @item info dos pde | |
16113 | @itemx info dos pte | |
16114 | These two commands display entries from, respectively, the Page | |
16115 | Directory and the Page Tables. Page Directories and Page Tables are | |
16116 | data structures which control how virtual memory addresses are mapped | |
16117 | into physical addresses. A Page Table includes an entry for every | |
16118 | page of memory that is mapped into the program's address space; there | |
16119 | may be several Page Tables, each one holding up to 4096 entries. A | |
16120 | Page Directory has up to 4096 entries, one each for every Page Table | |
16121 | that is currently in use. | |
104c1213 | 16122 | |
8e04817f AC |
16123 | Without an argument, @kbd{info dos pde} displays the entire Page |
16124 | Directory, and @kbd{info dos pte} displays all the entries in all of | |
16125 | the Page Tables. An argument, an integer expression, given to the | |
16126 | @kbd{info dos pde} command means display only that entry from the Page | |
16127 | Directory table. An argument given to the @kbd{info dos pte} command | |
16128 | means display entries from a single Page Table, the one pointed to by | |
16129 | the specified entry in the Page Directory. | |
104c1213 | 16130 | |
8e04817f AC |
16131 | @cindex direct memory access (DMA) on MS-DOS |
16132 | These commands are useful when your program uses @dfn{DMA} (Direct | |
16133 | Memory Access), which needs physical addresses to program the DMA | |
16134 | controller. | |
104c1213 | 16135 | |
8e04817f | 16136 | These commands are supported only with some DPMI servers. |
104c1213 | 16137 | |
8e04817f AC |
16138 | @cindex physical address from linear address |
16139 | @item info dos address-pte @var{addr} | |
16140 | This command displays the Page Table entry for a specified linear | |
514c4d71 EZ |
16141 | address. The argument @var{addr} is a linear address which should |
16142 | already have the appropriate segment's base address added to it, | |
16143 | because this command accepts addresses which may belong to @emph{any} | |
16144 | segment. For example, here's how to display the Page Table entry for | |
16145 | the page where a variable @code{i} is stored: | |
104c1213 | 16146 | |
b383017d | 16147 | @smallexample |
8e04817f AC |
16148 | @exdent @code{(@value{GDBP}) info dos address-pte __djgpp_base_address + (char *)&i} |
16149 | @exdent @code{Page Table entry for address 0x11a00d30:} | |
b383017d | 16150 | @exdent @code{Base=0x02698000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0xd30} |
8e04817f | 16151 | @end smallexample |
104c1213 | 16152 | |
8e04817f AC |
16153 | @noindent |
16154 | This says that @code{i} is stored at offset @code{0xd30} from the page | |
514c4d71 | 16155 | whose physical base address is @code{0x02698000}, and shows all the |
8e04817f | 16156 | attributes of that page. |
104c1213 | 16157 | |
8e04817f AC |
16158 | Note that you must cast the addresses of variables to a @code{char *}, |
16159 | since otherwise the value of @code{__djgpp_base_address}, the base | |
16160 | address of all variables and functions in a @sc{djgpp} program, will | |
16161 | be added using the rules of C pointer arithmetics: if @code{i} is | |
16162 | declared an @code{int}, @value{GDBN} will add 4 times the value of | |
16163 | @code{__djgpp_base_address} to the address of @code{i}. | |
104c1213 | 16164 | |
8e04817f AC |
16165 | Here's another example, it displays the Page Table entry for the |
16166 | transfer buffer: | |
104c1213 | 16167 | |
8e04817f AC |
16168 | @smallexample |
16169 | @exdent @code{(@value{GDBP}) info dos address-pte *((unsigned *)&_go32_info_block + 3)} | |
16170 | @exdent @code{Page Table entry for address 0x29110:} | |
16171 | @exdent @code{Base=0x00029000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0x110} | |
16172 | @end smallexample | |
104c1213 | 16173 | |
8e04817f AC |
16174 | @noindent |
16175 | (The @code{+ 3} offset is because the transfer buffer's address is the | |
514c4d71 EZ |
16176 | 3rd member of the @code{_go32_info_block} structure.) The output |
16177 | clearly shows that this DPMI server maps the addresses in conventional | |
16178 | memory 1:1, i.e.@: the physical (@code{0x00029000} + @code{0x110}) and | |
16179 | linear (@code{0x29110}) addresses are identical. | |
104c1213 | 16180 | |
8e04817f AC |
16181 | This command is supported only with some DPMI servers. |
16182 | @end table | |
104c1213 | 16183 | |
c45da7e6 | 16184 | @cindex DOS serial data link, remote debugging |
a8f24a35 EZ |
16185 | In addition to native debugging, the DJGPP port supports remote |
16186 | debugging via a serial data link. The following commands are specific | |
16187 | to remote serial debugging in the DJGPP port of @value{GDBN}. | |
16188 | ||
16189 | @table @code | |
16190 | @kindex set com1base | |
16191 | @kindex set com1irq | |
16192 | @kindex set com2base | |
16193 | @kindex set com2irq | |
16194 | @kindex set com3base | |
16195 | @kindex set com3irq | |
16196 | @kindex set com4base | |
16197 | @kindex set com4irq | |
16198 | @item set com1base @var{addr} | |
16199 | This command sets the base I/O port address of the @file{COM1} serial | |
16200 | port. | |
16201 | ||
16202 | @item set com1irq @var{irq} | |
16203 | This command sets the @dfn{Interrupt Request} (@code{IRQ}) line to use | |
16204 | for the @file{COM1} serial port. | |
16205 | ||
16206 | There are similar commands @samp{set com2base}, @samp{set com3irq}, | |
16207 | etc.@: for setting the port address and the @code{IRQ} lines for the | |
16208 | other 3 COM ports. | |
16209 | ||
16210 | @kindex show com1base | |
16211 | @kindex show com1irq | |
16212 | @kindex show com2base | |
16213 | @kindex show com2irq | |
16214 | @kindex show com3base | |
16215 | @kindex show com3irq | |
16216 | @kindex show com4base | |
16217 | @kindex show com4irq | |
16218 | The related commands @samp{show com1base}, @samp{show com1irq} etc.@: | |
16219 | display the current settings of the base address and the @code{IRQ} | |
16220 | lines used by the COM ports. | |
c45da7e6 EZ |
16221 | |
16222 | @item info serial | |
16223 | @kindex info serial | |
16224 | @cindex DOS serial port status | |
16225 | This command prints the status of the 4 DOS serial ports. For each | |
16226 | port, it prints whether it's active or not, its I/O base address and | |
16227 | IRQ number, whether it uses a 16550-style FIFO, its baudrate, and the | |
16228 | counts of various errors encountered so far. | |
a8f24a35 EZ |
16229 | @end table |
16230 | ||
16231 | ||
78c47bea | 16232 | @node Cygwin Native |
79a6e687 | 16233 | @subsection Features for Debugging MS Windows PE Executables |
78c47bea PM |
16234 | @cindex MS Windows debugging |
16235 | @cindex native Cygwin debugging | |
16236 | @cindex Cygwin-specific commands | |
16237 | ||
be448670 | 16238 | @value{GDBN} supports native debugging of MS Windows programs, including |
cbb8f428 EZ |
16239 | DLLs with and without symbolic debugging information. |
16240 | ||
16241 | @cindex Ctrl-BREAK, MS-Windows | |
16242 | @cindex interrupt debuggee on MS-Windows | |
16243 | MS-Windows programs that call @code{SetConsoleMode} to switch off the | |
16244 | special meaning of the @samp{Ctrl-C} keystroke cannot be interrupted | |
16245 | by typing @kbd{C-c}. For this reason, @value{GDBN} on MS-Windows | |
16246 | supports @kbd{C-@key{BREAK}} as an alternative interrupt key | |
16247 | sequence, which can be used to interrupt the debuggee even if it | |
16248 | ignores @kbd{C-c}. | |
16249 | ||
16250 | There are various additional Cygwin-specific commands, described in | |
16251 | this section. Working with DLLs that have no debugging symbols is | |
16252 | described in @ref{Non-debug DLL Symbols}. | |
78c47bea PM |
16253 | |
16254 | @table @code | |
16255 | @kindex info w32 | |
16256 | @item info w32 | |
db2e3e2e | 16257 | This is a prefix of MS Windows-specific commands which print |
78c47bea PM |
16258 | information about the target system and important OS structures. |
16259 | ||
16260 | @item info w32 selector | |
16261 | This command displays information returned by | |
16262 | the Win32 API @code{GetThreadSelectorEntry} function. | |
16263 | It takes an optional argument that is evaluated to | |
16264 | a long value to give the information about this given selector. | |
16265 | Without argument, this command displays information | |
d3e8051b | 16266 | about the six segment registers. |
78c47bea PM |
16267 | |
16268 | @kindex info dll | |
16269 | @item info dll | |
db2e3e2e | 16270 | This is a Cygwin-specific alias of @code{info shared}. |
78c47bea PM |
16271 | |
16272 | @kindex dll-symbols | |
16273 | @item dll-symbols | |
16274 | This command loads symbols from a dll similarly to | |
16275 | add-sym command but without the need to specify a base address. | |
16276 | ||
be90c084 | 16277 | @kindex set cygwin-exceptions |
e16b02ee EZ |
16278 | @cindex debugging the Cygwin DLL |
16279 | @cindex Cygwin DLL, debugging | |
be90c084 | 16280 | @item set cygwin-exceptions @var{mode} |
e16b02ee EZ |
16281 | If @var{mode} is @code{on}, @value{GDBN} will break on exceptions that |
16282 | happen inside the Cygwin DLL. If @var{mode} is @code{off}, | |
16283 | @value{GDBN} will delay recognition of exceptions, and may ignore some | |
16284 | exceptions which seem to be caused by internal Cygwin DLL | |
16285 | ``bookkeeping''. This option is meant primarily for debugging the | |
16286 | Cygwin DLL itself; the default value is @code{off} to avoid annoying | |
16287 | @value{GDBN} users with false @code{SIGSEGV} signals. | |
be90c084 CF |
16288 | |
16289 | @kindex show cygwin-exceptions | |
16290 | @item show cygwin-exceptions | |
e16b02ee EZ |
16291 | Displays whether @value{GDBN} will break on exceptions that happen |
16292 | inside the Cygwin DLL itself. | |
be90c084 | 16293 | |
b383017d | 16294 | @kindex set new-console |
78c47bea | 16295 | @item set new-console @var{mode} |
b383017d | 16296 | If @var{mode} is @code{on} the debuggee will |
78c47bea PM |
16297 | be started in a new console on next start. |
16298 | If @var{mode} is @code{off}i, the debuggee will | |
16299 | be started in the same console as the debugger. | |
16300 | ||
16301 | @kindex show new-console | |
16302 | @item show new-console | |
16303 | Displays whether a new console is used | |
16304 | when the debuggee is started. | |
16305 | ||
16306 | @kindex set new-group | |
16307 | @item set new-group @var{mode} | |
16308 | This boolean value controls whether the debuggee should | |
16309 | start a new group or stay in the same group as the debugger. | |
16310 | This affects the way the Windows OS handles | |
c8aa23ab | 16311 | @samp{Ctrl-C}. |
78c47bea PM |
16312 | |
16313 | @kindex show new-group | |
16314 | @item show new-group | |
16315 | Displays current value of new-group boolean. | |
16316 | ||
16317 | @kindex set debugevents | |
16318 | @item set debugevents | |
219eec71 EZ |
16319 | This boolean value adds debug output concerning kernel events related |
16320 | to the debuggee seen by the debugger. This includes events that | |
16321 | signal thread and process creation and exit, DLL loading and | |
16322 | unloading, console interrupts, and debugging messages produced by the | |
16323 | Windows @code{OutputDebugString} API call. | |
78c47bea PM |
16324 | |
16325 | @kindex set debugexec | |
16326 | @item set debugexec | |
b383017d | 16327 | This boolean value adds debug output concerning execute events |
219eec71 | 16328 | (such as resume thread) seen by the debugger. |
78c47bea PM |
16329 | |
16330 | @kindex set debugexceptions | |
16331 | @item set debugexceptions | |
219eec71 EZ |
16332 | This boolean value adds debug output concerning exceptions in the |
16333 | debuggee seen by the debugger. | |
78c47bea PM |
16334 | |
16335 | @kindex set debugmemory | |
16336 | @item set debugmemory | |
219eec71 EZ |
16337 | This boolean value adds debug output concerning debuggee memory reads |
16338 | and writes by the debugger. | |
78c47bea PM |
16339 | |
16340 | @kindex set shell | |
16341 | @item set shell | |
16342 | This boolean values specifies whether the debuggee is called | |
16343 | via a shell or directly (default value is on). | |
16344 | ||
16345 | @kindex show shell | |
16346 | @item show shell | |
16347 | Displays if the debuggee will be started with a shell. | |
16348 | ||
16349 | @end table | |
16350 | ||
be448670 | 16351 | @menu |
79a6e687 | 16352 | * Non-debug DLL Symbols:: Support for DLLs without debugging symbols |
be448670 CF |
16353 | @end menu |
16354 | ||
79a6e687 BW |
16355 | @node Non-debug DLL Symbols |
16356 | @subsubsection Support for DLLs without Debugging Symbols | |
be448670 CF |
16357 | @cindex DLLs with no debugging symbols |
16358 | @cindex Minimal symbols and DLLs | |
16359 | ||
16360 | Very often on windows, some of the DLLs that your program relies on do | |
16361 | not include symbolic debugging information (for example, | |
db2e3e2e | 16362 | @file{kernel32.dll}). When @value{GDBN} doesn't recognize any debugging |
be448670 | 16363 | symbols in a DLL, it relies on the minimal amount of symbolic |
db2e3e2e | 16364 | information contained in the DLL's export table. This section |
be448670 CF |
16365 | describes working with such symbols, known internally to @value{GDBN} as |
16366 | ``minimal symbols''. | |
16367 | ||
16368 | Note that before the debugged program has started execution, no DLLs | |
db2e3e2e | 16369 | will have been loaded. The easiest way around this problem is simply to |
be448670 | 16370 | start the program --- either by setting a breakpoint or letting the |
db2e3e2e | 16371 | program run once to completion. It is also possible to force |
be448670 | 16372 | @value{GDBN} to load a particular DLL before starting the executable --- |
12c27660 | 16373 | see the shared library information in @ref{Files}, or the |
db2e3e2e | 16374 | @code{dll-symbols} command in @ref{Cygwin Native}. Currently, |
be448670 CF |
16375 | explicitly loading symbols from a DLL with no debugging information will |
16376 | cause the symbol names to be duplicated in @value{GDBN}'s lookup table, | |
16377 | which may adversely affect symbol lookup performance. | |
16378 | ||
79a6e687 | 16379 | @subsubsection DLL Name Prefixes |
be448670 CF |
16380 | |
16381 | In keeping with the naming conventions used by the Microsoft debugging | |
16382 | tools, DLL export symbols are made available with a prefix based on the | |
16383 | DLL name, for instance @code{KERNEL32!CreateFileA}. The plain name is | |
16384 | also entered into the symbol table, so @code{CreateFileA} is often | |
99e008fe | 16385 | sufficient. In some cases there will be name clashes within a program |
be448670 CF |
16386 | (particularly if the executable itself includes full debugging symbols) |
16387 | necessitating the use of the fully qualified name when referring to the | |
99e008fe | 16388 | contents of the DLL. Use single-quotes around the name to avoid the |
be448670 CF |
16389 | exclamation mark (``!'') being interpreted as a language operator. |
16390 | ||
16391 | Note that the internal name of the DLL may be all upper-case, even | |
99e008fe | 16392 | though the file name of the DLL is lower-case, or vice-versa. Since |
be448670 CF |
16393 | symbols within @value{GDBN} are @emph{case-sensitive} this may cause |
16394 | some confusion. If in doubt, try the @code{info functions} and | |
0869d01b NR |
16395 | @code{info variables} commands or even @code{maint print msymbols} |
16396 | (@pxref{Symbols}). Here's an example: | |
be448670 CF |
16397 | |
16398 | @smallexample | |
f7dc1244 | 16399 | (@value{GDBP}) info function CreateFileA |
be448670 CF |
16400 | All functions matching regular expression "CreateFileA": |
16401 | ||
16402 | Non-debugging symbols: | |
16403 | 0x77e885f4 CreateFileA | |
16404 | 0x77e885f4 KERNEL32!CreateFileA | |
16405 | @end smallexample | |
16406 | ||
16407 | @smallexample | |
f7dc1244 | 16408 | (@value{GDBP}) info function ! |
be448670 CF |
16409 | All functions matching regular expression "!": |
16410 | ||
16411 | Non-debugging symbols: | |
16412 | 0x6100114c cygwin1!__assert | |
16413 | 0x61004034 cygwin1!_dll_crt0@@0 | |
16414 | 0x61004240 cygwin1!dll_crt0(per_process *) | |
16415 | [etc...] | |
16416 | @end smallexample | |
16417 | ||
79a6e687 | 16418 | @subsubsection Working with Minimal Symbols |
be448670 CF |
16419 | |
16420 | Symbols extracted from a DLL's export table do not contain very much | |
16421 | type information. All that @value{GDBN} can do is guess whether a symbol | |
16422 | refers to a function or variable depending on the linker section that | |
16423 | contains the symbol. Also note that the actual contents of the memory | |
16424 | contained in a DLL are not available unless the program is running. This | |
16425 | means that you cannot examine the contents of a variable or disassemble | |
16426 | a function within a DLL without a running program. | |
16427 | ||
16428 | Variables are generally treated as pointers and dereferenced | |
16429 | automatically. For this reason, it is often necessary to prefix a | |
16430 | variable name with the address-of operator (``&'') and provide explicit | |
16431 | type information in the command. Here's an example of the type of | |
16432 | problem: | |
16433 | ||
16434 | @smallexample | |
f7dc1244 | 16435 | (@value{GDBP}) print 'cygwin1!__argv' |
be448670 CF |
16436 | $1 = 268572168 |
16437 | @end smallexample | |
16438 | ||
16439 | @smallexample | |
f7dc1244 | 16440 | (@value{GDBP}) x 'cygwin1!__argv' |
be448670 CF |
16441 | 0x10021610: "\230y\"" |
16442 | @end smallexample | |
16443 | ||
16444 | And two possible solutions: | |
16445 | ||
16446 | @smallexample | |
f7dc1244 | 16447 | (@value{GDBP}) print ((char **)'cygwin1!__argv')[0] |
be448670 CF |
16448 | $2 = 0x22fd98 "/cygdrive/c/mydirectory/myprogram" |
16449 | @end smallexample | |
16450 | ||
16451 | @smallexample | |
f7dc1244 | 16452 | (@value{GDBP}) x/2x &'cygwin1!__argv' |
be448670 | 16453 | 0x610c0aa8 <cygwin1!__argv>: 0x10021608 0x00000000 |
f7dc1244 | 16454 | (@value{GDBP}) x/x 0x10021608 |
be448670 | 16455 | 0x10021608: 0x0022fd98 |
f7dc1244 | 16456 | (@value{GDBP}) x/s 0x0022fd98 |
be448670 CF |
16457 | 0x22fd98: "/cygdrive/c/mydirectory/myprogram" |
16458 | @end smallexample | |
16459 | ||
16460 | Setting a break point within a DLL is possible even before the program | |
16461 | starts execution. However, under these circumstances, @value{GDBN} can't | |
16462 | examine the initial instructions of the function in order to skip the | |
16463 | function's frame set-up code. You can work around this by using ``*&'' | |
16464 | to set the breakpoint at a raw memory address: | |
16465 | ||
16466 | @smallexample | |
f7dc1244 | 16467 | (@value{GDBP}) break *&'python22!PyOS_Readline' |
be448670 CF |
16468 | Breakpoint 1 at 0x1e04eff0 |
16469 | @end smallexample | |
16470 | ||
16471 | The author of these extensions is not entirely convinced that setting a | |
16472 | break point within a shared DLL like @file{kernel32.dll} is completely | |
16473 | safe. | |
16474 | ||
14d6dd68 | 16475 | @node Hurd Native |
79a6e687 | 16476 | @subsection Commands Specific to @sc{gnu} Hurd Systems |
14d6dd68 EZ |
16477 | @cindex @sc{gnu} Hurd debugging |
16478 | ||
16479 | This subsection describes @value{GDBN} commands specific to the | |
16480 | @sc{gnu} Hurd native debugging. | |
16481 | ||
16482 | @table @code | |
16483 | @item set signals | |
16484 | @itemx set sigs | |
16485 | @kindex set signals@r{, Hurd command} | |
16486 | @kindex set sigs@r{, Hurd command} | |
16487 | This command toggles the state of inferior signal interception by | |
16488 | @value{GDBN}. Mach exceptions, such as breakpoint traps, are not | |
16489 | affected by this command. @code{sigs} is a shorthand alias for | |
16490 | @code{signals}. | |
16491 | ||
16492 | @item show signals | |
16493 | @itemx show sigs | |
16494 | @kindex show signals@r{, Hurd command} | |
16495 | @kindex show sigs@r{, Hurd command} | |
16496 | Show the current state of intercepting inferior's signals. | |
16497 | ||
16498 | @item set signal-thread | |
16499 | @itemx set sigthread | |
16500 | @kindex set signal-thread | |
16501 | @kindex set sigthread | |
16502 | This command tells @value{GDBN} which thread is the @code{libc} signal | |
16503 | thread. That thread is run when a signal is delivered to a running | |
16504 | process. @code{set sigthread} is the shorthand alias of @code{set | |
16505 | signal-thread}. | |
16506 | ||
16507 | @item show signal-thread | |
16508 | @itemx show sigthread | |
16509 | @kindex show signal-thread | |
16510 | @kindex show sigthread | |
16511 | These two commands show which thread will run when the inferior is | |
16512 | delivered a signal. | |
16513 | ||
16514 | @item set stopped | |
16515 | @kindex set stopped@r{, Hurd command} | |
16516 | This commands tells @value{GDBN} that the inferior process is stopped, | |
16517 | as with the @code{SIGSTOP} signal. The stopped process can be | |
16518 | continued by delivering a signal to it. | |
16519 | ||
16520 | @item show stopped | |
16521 | @kindex show stopped@r{, Hurd command} | |
16522 | This command shows whether @value{GDBN} thinks the debuggee is | |
16523 | stopped. | |
16524 | ||
16525 | @item set exceptions | |
16526 | @kindex set exceptions@r{, Hurd command} | |
16527 | Use this command to turn off trapping of exceptions in the inferior. | |
16528 | When exception trapping is off, neither breakpoints nor | |
16529 | single-stepping will work. To restore the default, set exception | |
16530 | trapping on. | |
16531 | ||
16532 | @item show exceptions | |
16533 | @kindex show exceptions@r{, Hurd command} | |
16534 | Show the current state of trapping exceptions in the inferior. | |
16535 | ||
16536 | @item set task pause | |
16537 | @kindex set task@r{, Hurd commands} | |
16538 | @cindex task attributes (@sc{gnu} Hurd) | |
16539 | @cindex pause current task (@sc{gnu} Hurd) | |
16540 | This command toggles task suspension when @value{GDBN} has control. | |
16541 | Setting it to on takes effect immediately, and the task is suspended | |
16542 | whenever @value{GDBN} gets control. Setting it to off will take | |
16543 | effect the next time the inferior is continued. If this option is set | |
16544 | to off, you can use @code{set thread default pause on} or @code{set | |
16545 | thread pause on} (see below) to pause individual threads. | |
16546 | ||
16547 | @item show task pause | |
16548 | @kindex show task@r{, Hurd commands} | |
16549 | Show the current state of task suspension. | |
16550 | ||
16551 | @item set task detach-suspend-count | |
16552 | @cindex task suspend count | |
16553 | @cindex detach from task, @sc{gnu} Hurd | |
16554 | This command sets the suspend count the task will be left with when | |
16555 | @value{GDBN} detaches from it. | |
16556 | ||
16557 | @item show task detach-suspend-count | |
16558 | Show the suspend count the task will be left with when detaching. | |
16559 | ||
16560 | @item set task exception-port | |
16561 | @itemx set task excp | |
16562 | @cindex task exception port, @sc{gnu} Hurd | |
16563 | This command sets the task exception port to which @value{GDBN} will | |
16564 | forward exceptions. The argument should be the value of the @dfn{send | |
16565 | rights} of the task. @code{set task excp} is a shorthand alias. | |
16566 | ||
16567 | @item set noninvasive | |
16568 | @cindex noninvasive task options | |
16569 | This command switches @value{GDBN} to a mode that is the least | |
16570 | invasive as far as interfering with the inferior is concerned. This | |
16571 | is the same as using @code{set task pause}, @code{set exceptions}, and | |
16572 | @code{set signals} to values opposite to the defaults. | |
16573 | ||
16574 | @item info send-rights | |
16575 | @itemx info receive-rights | |
16576 | @itemx info port-rights | |
16577 | @itemx info port-sets | |
16578 | @itemx info dead-names | |
16579 | @itemx info ports | |
16580 | @itemx info psets | |
16581 | @cindex send rights, @sc{gnu} Hurd | |
16582 | @cindex receive rights, @sc{gnu} Hurd | |
16583 | @cindex port rights, @sc{gnu} Hurd | |
16584 | @cindex port sets, @sc{gnu} Hurd | |
16585 | @cindex dead names, @sc{gnu} Hurd | |
16586 | These commands display information about, respectively, send rights, | |
16587 | receive rights, port rights, port sets, and dead names of a task. | |
16588 | There are also shorthand aliases: @code{info ports} for @code{info | |
16589 | port-rights} and @code{info psets} for @code{info port-sets}. | |
16590 | ||
16591 | @item set thread pause | |
16592 | @kindex set thread@r{, Hurd command} | |
16593 | @cindex thread properties, @sc{gnu} Hurd | |
16594 | @cindex pause current thread (@sc{gnu} Hurd) | |
16595 | This command toggles current thread suspension when @value{GDBN} has | |
16596 | control. Setting it to on takes effect immediately, and the current | |
16597 | thread is suspended whenever @value{GDBN} gets control. Setting it to | |
16598 | off will take effect the next time the inferior is continued. | |
16599 | Normally, this command has no effect, since when @value{GDBN} has | |
16600 | control, the whole task is suspended. However, if you used @code{set | |
16601 | task pause off} (see above), this command comes in handy to suspend | |
16602 | only the current thread. | |
16603 | ||
16604 | @item show thread pause | |
16605 | @kindex show thread@r{, Hurd command} | |
16606 | This command shows the state of current thread suspension. | |
16607 | ||
16608 | @item set thread run | |
d3e8051b | 16609 | This command sets whether the current thread is allowed to run. |
14d6dd68 EZ |
16610 | |
16611 | @item show thread run | |
16612 | Show whether the current thread is allowed to run. | |
16613 | ||
16614 | @item set thread detach-suspend-count | |
16615 | @cindex thread suspend count, @sc{gnu} Hurd | |
16616 | @cindex detach from thread, @sc{gnu} Hurd | |
16617 | This command sets the suspend count @value{GDBN} will leave on a | |
16618 | thread when detaching. This number is relative to the suspend count | |
16619 | found by @value{GDBN} when it notices the thread; use @code{set thread | |
16620 | takeover-suspend-count} to force it to an absolute value. | |
16621 | ||
16622 | @item show thread detach-suspend-count | |
16623 | Show the suspend count @value{GDBN} will leave on the thread when | |
16624 | detaching. | |
16625 | ||
16626 | @item set thread exception-port | |
16627 | @itemx set thread excp | |
16628 | Set the thread exception port to which to forward exceptions. This | |
16629 | overrides the port set by @code{set task exception-port} (see above). | |
16630 | @code{set thread excp} is the shorthand alias. | |
16631 | ||
16632 | @item set thread takeover-suspend-count | |
16633 | Normally, @value{GDBN}'s thread suspend counts are relative to the | |
16634 | value @value{GDBN} finds when it notices each thread. This command | |
16635 | changes the suspend counts to be absolute instead. | |
16636 | ||
16637 | @item set thread default | |
16638 | @itemx show thread default | |
16639 | @cindex thread default settings, @sc{gnu} Hurd | |
16640 | Each of the above @code{set thread} commands has a @code{set thread | |
16641 | default} counterpart (e.g., @code{set thread default pause}, @code{set | |
16642 | thread default exception-port}, etc.). The @code{thread default} | |
16643 | variety of commands sets the default thread properties for all | |
16644 | threads; you can then change the properties of individual threads with | |
16645 | the non-default commands. | |
16646 | @end table | |
16647 | ||
16648 | ||
a64548ea EZ |
16649 | @node Neutrino |
16650 | @subsection QNX Neutrino | |
16651 | @cindex QNX Neutrino | |
16652 | ||
16653 | @value{GDBN} provides the following commands specific to the QNX | |
16654 | Neutrino target: | |
16655 | ||
16656 | @table @code | |
16657 | @item set debug nto-debug | |
16658 | @kindex set debug nto-debug | |
16659 | When set to on, enables debugging messages specific to the QNX | |
16660 | Neutrino support. | |
16661 | ||
16662 | @item show debug nto-debug | |
16663 | @kindex show debug nto-debug | |
16664 | Show the current state of QNX Neutrino messages. | |
16665 | @end table | |
16666 | ||
a80b95ba TG |
16667 | @node Darwin |
16668 | @subsection Darwin | |
16669 | @cindex Darwin | |
16670 | ||
16671 | @value{GDBN} provides the following commands specific to the Darwin target: | |
16672 | ||
16673 | @table @code | |
16674 | @item set debug darwin @var{num} | |
16675 | @kindex set debug darwin | |
16676 | When set to a non zero value, enables debugging messages specific to | |
16677 | the Darwin support. Higher values produce more verbose output. | |
16678 | ||
16679 | @item show debug darwin | |
16680 | @kindex show debug darwin | |
16681 | Show the current state of Darwin messages. | |
16682 | ||
16683 | @item set debug mach-o @var{num} | |
16684 | @kindex set debug mach-o | |
16685 | When set to a non zero value, enables debugging messages while | |
16686 | @value{GDBN} is reading Darwin object files. (@dfn{Mach-O} is the | |
16687 | file format used on Darwin for object and executable files.) Higher | |
16688 | values produce more verbose output. This is a command to diagnose | |
16689 | problems internal to @value{GDBN} and should not be needed in normal | |
16690 | usage. | |
16691 | ||
16692 | @item show debug mach-o | |
16693 | @kindex show debug mach-o | |
16694 | Show the current state of Mach-O file messages. | |
16695 | ||
16696 | @item set mach-exceptions on | |
16697 | @itemx set mach-exceptions off | |
16698 | @kindex set mach-exceptions | |
16699 | On Darwin, faults are first reported as a Mach exception and are then | |
16700 | mapped to a Posix signal. Use this command to turn on trapping of | |
16701 | Mach exceptions in the inferior. This might be sometimes useful to | |
16702 | better understand the cause of a fault. The default is off. | |
16703 | ||
16704 | @item show mach-exceptions | |
16705 | @kindex show mach-exceptions | |
16706 | Show the current state of exceptions trapping. | |
16707 | @end table | |
16708 | ||
a64548ea | 16709 | |
8e04817f AC |
16710 | @node Embedded OS |
16711 | @section Embedded Operating Systems | |
104c1213 | 16712 | |
8e04817f AC |
16713 | This section describes configurations involving the debugging of |
16714 | embedded operating systems that are available for several different | |
16715 | architectures. | |
d4f3574e | 16716 | |
8e04817f AC |
16717 | @menu |
16718 | * VxWorks:: Using @value{GDBN} with VxWorks | |
16719 | @end menu | |
104c1213 | 16720 | |
8e04817f AC |
16721 | @value{GDBN} includes the ability to debug programs running on |
16722 | various real-time operating systems. | |
104c1213 | 16723 | |
8e04817f AC |
16724 | @node VxWorks |
16725 | @subsection Using @value{GDBN} with VxWorks | |
104c1213 | 16726 | |
8e04817f | 16727 | @cindex VxWorks |
104c1213 | 16728 | |
8e04817f | 16729 | @table @code |
104c1213 | 16730 | |
8e04817f AC |
16731 | @kindex target vxworks |
16732 | @item target vxworks @var{machinename} | |
16733 | A VxWorks system, attached via TCP/IP. The argument @var{machinename} | |
16734 | is the target system's machine name or IP address. | |
104c1213 | 16735 | |
8e04817f | 16736 | @end table |
104c1213 | 16737 | |
8e04817f AC |
16738 | On VxWorks, @code{load} links @var{filename} dynamically on the |
16739 | current target system as well as adding its symbols in @value{GDBN}. | |
104c1213 | 16740 | |
8e04817f AC |
16741 | @value{GDBN} enables developers to spawn and debug tasks running on networked |
16742 | VxWorks targets from a Unix host. Already-running tasks spawned from | |
16743 | the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on | |
16744 | both the Unix host and on the VxWorks target. The program | |
16745 | @code{@value{GDBP}} is installed and executed on the Unix host. (It may be | |
16746 | installed with the name @code{vxgdb}, to distinguish it from a | |
16747 | @value{GDBN} for debugging programs on the host itself.) | |
104c1213 | 16748 | |
8e04817f AC |
16749 | @table @code |
16750 | @item VxWorks-timeout @var{args} | |
16751 | @kindex vxworks-timeout | |
16752 | All VxWorks-based targets now support the option @code{vxworks-timeout}. | |
16753 | This option is set by the user, and @var{args} represents the number of | |
16754 | seconds @value{GDBN} waits for responses to rpc's. You might use this if | |
16755 | your VxWorks target is a slow software simulator or is on the far side | |
16756 | of a thin network line. | |
16757 | @end table | |
104c1213 | 16758 | |
8e04817f AC |
16759 | The following information on connecting to VxWorks was current when |
16760 | this manual was produced; newer releases of VxWorks may use revised | |
16761 | procedures. | |
104c1213 | 16762 | |
4644b6e3 | 16763 | @findex INCLUDE_RDB |
8e04817f AC |
16764 | To use @value{GDBN} with VxWorks, you must rebuild your VxWorks kernel |
16765 | to include the remote debugging interface routines in the VxWorks | |
16766 | library @file{rdb.a}. To do this, define @code{INCLUDE_RDB} in the | |
16767 | VxWorks configuration file @file{configAll.h} and rebuild your VxWorks | |
16768 | kernel. The resulting kernel contains @file{rdb.a}, and spawns the | |
16769 | source debugging task @code{tRdbTask} when VxWorks is booted. For more | |
16770 | information on configuring and remaking VxWorks, see the manufacturer's | |
16771 | manual. | |
16772 | @c VxWorks, see the @cite{VxWorks Programmer's Guide}. | |
104c1213 | 16773 | |
8e04817f AC |
16774 | Once you have included @file{rdb.a} in your VxWorks system image and set |
16775 | your Unix execution search path to find @value{GDBN}, you are ready to | |
16776 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} (or | |
16777 | @code{vxgdb}, depending on your installation). | |
104c1213 | 16778 | |
8e04817f | 16779 | @value{GDBN} comes up showing the prompt: |
104c1213 | 16780 | |
474c8240 | 16781 | @smallexample |
8e04817f | 16782 | (vxgdb) |
474c8240 | 16783 | @end smallexample |
104c1213 | 16784 | |
8e04817f AC |
16785 | @menu |
16786 | * VxWorks Connection:: Connecting to VxWorks | |
16787 | * VxWorks Download:: VxWorks download | |
16788 | * VxWorks Attach:: Running tasks | |
16789 | @end menu | |
104c1213 | 16790 | |
8e04817f AC |
16791 | @node VxWorks Connection |
16792 | @subsubsection Connecting to VxWorks | |
104c1213 | 16793 | |
8e04817f AC |
16794 | The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the |
16795 | network. To connect to a target whose host name is ``@code{tt}'', type: | |
104c1213 | 16796 | |
474c8240 | 16797 | @smallexample |
8e04817f | 16798 | (vxgdb) target vxworks tt |
474c8240 | 16799 | @end smallexample |
104c1213 | 16800 | |
8e04817f AC |
16801 | @need 750 |
16802 | @value{GDBN} displays messages like these: | |
104c1213 | 16803 | |
8e04817f AC |
16804 | @smallexample |
16805 | Attaching remote machine across net... | |
16806 | Connected to tt. | |
16807 | @end smallexample | |
104c1213 | 16808 | |
8e04817f AC |
16809 | @need 1000 |
16810 | @value{GDBN} then attempts to read the symbol tables of any object modules | |
16811 | loaded into the VxWorks target since it was last booted. @value{GDBN} locates | |
16812 | these files by searching the directories listed in the command search | |
79a6e687 | 16813 | path (@pxref{Environment, ,Your Program's Environment}); if it fails |
8e04817f | 16814 | to find an object file, it displays a message such as: |
5d161b24 | 16815 | |
474c8240 | 16816 | @smallexample |
8e04817f | 16817 | prog.o: No such file or directory. |
474c8240 | 16818 | @end smallexample |
104c1213 | 16819 | |
8e04817f AC |
16820 | When this happens, add the appropriate directory to the search path with |
16821 | the @value{GDBN} command @code{path}, and execute the @code{target} | |
16822 | command again. | |
104c1213 | 16823 | |
8e04817f | 16824 | @node VxWorks Download |
79a6e687 | 16825 | @subsubsection VxWorks Download |
104c1213 | 16826 | |
8e04817f AC |
16827 | @cindex download to VxWorks |
16828 | If you have connected to the VxWorks target and you want to debug an | |
16829 | object that has not yet been loaded, you can use the @value{GDBN} | |
16830 | @code{load} command to download a file from Unix to VxWorks | |
16831 | incrementally. The object file given as an argument to the @code{load} | |
16832 | command is actually opened twice: first by the VxWorks target in order | |
16833 | to download the code, then by @value{GDBN} in order to read the symbol | |
16834 | table. This can lead to problems if the current working directories on | |
16835 | the two systems differ. If both systems have NFS mounted the same | |
16836 | filesystems, you can avoid these problems by using absolute paths. | |
16837 | Otherwise, it is simplest to set the working directory on both systems | |
16838 | to the directory in which the object file resides, and then to reference | |
16839 | the file by its name, without any path. For instance, a program | |
16840 | @file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks | |
16841 | and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this | |
16842 | program, type this on VxWorks: | |
104c1213 | 16843 | |
474c8240 | 16844 | @smallexample |
8e04817f | 16845 | -> cd "@var{vxpath}/vw/demo/rdb" |
474c8240 | 16846 | @end smallexample |
104c1213 | 16847 | |
8e04817f AC |
16848 | @noindent |
16849 | Then, in @value{GDBN}, type: | |
104c1213 | 16850 | |
474c8240 | 16851 | @smallexample |
8e04817f AC |
16852 | (vxgdb) cd @var{hostpath}/vw/demo/rdb |
16853 | (vxgdb) load prog.o | |
474c8240 | 16854 | @end smallexample |
104c1213 | 16855 | |
8e04817f | 16856 | @value{GDBN} displays a response similar to this: |
104c1213 | 16857 | |
8e04817f AC |
16858 | @smallexample |
16859 | Reading symbol data from wherever/vw/demo/rdb/prog.o... done. | |
16860 | @end smallexample | |
104c1213 | 16861 | |
8e04817f AC |
16862 | You can also use the @code{load} command to reload an object module |
16863 | after editing and recompiling the corresponding source file. Note that | |
16864 | this makes @value{GDBN} delete all currently-defined breakpoints, | |
16865 | auto-displays, and convenience variables, and to clear the value | |
16866 | history. (This is necessary in order to preserve the integrity of | |
16867 | debugger's data structures that reference the target system's symbol | |
16868 | table.) | |
104c1213 | 16869 | |
8e04817f | 16870 | @node VxWorks Attach |
79a6e687 | 16871 | @subsubsection Running Tasks |
104c1213 JM |
16872 | |
16873 | @cindex running VxWorks tasks | |
16874 | You can also attach to an existing task using the @code{attach} command as | |
16875 | follows: | |
16876 | ||
474c8240 | 16877 | @smallexample |
104c1213 | 16878 | (vxgdb) attach @var{task} |
474c8240 | 16879 | @end smallexample |
104c1213 JM |
16880 | |
16881 | @noindent | |
16882 | where @var{task} is the VxWorks hexadecimal task ID. The task can be running | |
16883 | or suspended when you attach to it. Running tasks are suspended at | |
16884 | the time of attachment. | |
16885 | ||
6d2ebf8b | 16886 | @node Embedded Processors |
104c1213 JM |
16887 | @section Embedded Processors |
16888 | ||
16889 | This section goes into details specific to particular embedded | |
16890 | configurations. | |
16891 | ||
c45da7e6 EZ |
16892 | @cindex send command to simulator |
16893 | Whenever a specific embedded processor has a simulator, @value{GDBN} | |
16894 | allows to send an arbitrary command to the simulator. | |
16895 | ||
16896 | @table @code | |
16897 | @item sim @var{command} | |
16898 | @kindex sim@r{, a command} | |
16899 | Send an arbitrary @var{command} string to the simulator. Consult the | |
16900 | documentation for the specific simulator in use for information about | |
16901 | acceptable commands. | |
16902 | @end table | |
16903 | ||
7d86b5d5 | 16904 | |
104c1213 | 16905 | @menu |
c45da7e6 | 16906 | * ARM:: ARM RDI |
172c2a43 | 16907 | * M32R/D:: Renesas M32R/D |
104c1213 | 16908 | * M68K:: Motorola M68K |
08be9d71 | 16909 | * MicroBlaze:: Xilinx MicroBlaze |
104c1213 | 16910 | * MIPS Embedded:: MIPS Embedded |
a37295f9 | 16911 | * OpenRISC 1000:: OpenRisc 1000 |
104c1213 | 16912 | * PA:: HP PA Embedded |
4acd40f3 | 16913 | * PowerPC Embedded:: PowerPC Embedded |
104c1213 JM |
16914 | * Sparclet:: Tsqware Sparclet |
16915 | * Sparclite:: Fujitsu Sparclite | |
104c1213 | 16916 | * Z8000:: Zilog Z8000 |
a64548ea EZ |
16917 | * AVR:: Atmel AVR |
16918 | * CRIS:: CRIS | |
16919 | * Super-H:: Renesas Super-H | |
104c1213 JM |
16920 | @end menu |
16921 | ||
6d2ebf8b | 16922 | @node ARM |
104c1213 | 16923 | @subsection ARM |
c45da7e6 | 16924 | @cindex ARM RDI |
104c1213 JM |
16925 | |
16926 | @table @code | |
8e04817f AC |
16927 | @kindex target rdi |
16928 | @item target rdi @var{dev} | |
16929 | ARM Angel monitor, via RDI library interface to ADP protocol. You may | |
16930 | use this target to communicate with both boards running the Angel | |
16931 | monitor, or with the EmbeddedICE JTAG debug device. | |
16932 | ||
16933 | @kindex target rdp | |
16934 | @item target rdp @var{dev} | |
16935 | ARM Demon monitor. | |
16936 | ||
16937 | @end table | |
16938 | ||
e2f4edfd EZ |
16939 | @value{GDBN} provides the following ARM-specific commands: |
16940 | ||
16941 | @table @code | |
16942 | @item set arm disassembler | |
16943 | @kindex set arm | |
16944 | This commands selects from a list of disassembly styles. The | |
16945 | @code{"std"} style is the standard style. | |
16946 | ||
16947 | @item show arm disassembler | |
16948 | @kindex show arm | |
16949 | Show the current disassembly style. | |
16950 | ||
16951 | @item set arm apcs32 | |
16952 | @cindex ARM 32-bit mode | |
16953 | This command toggles ARM operation mode between 32-bit and 26-bit. | |
16954 | ||
16955 | @item show arm apcs32 | |
16956 | Display the current usage of the ARM 32-bit mode. | |
16957 | ||
16958 | @item set arm fpu @var{fputype} | |
16959 | This command sets the ARM floating-point unit (FPU) type. The | |
16960 | argument @var{fputype} can be one of these: | |
16961 | ||
16962 | @table @code | |
16963 | @item auto | |
16964 | Determine the FPU type by querying the OS ABI. | |
16965 | @item softfpa | |
16966 | Software FPU, with mixed-endian doubles on little-endian ARM | |
16967 | processors. | |
16968 | @item fpa | |
16969 | GCC-compiled FPA co-processor. | |
16970 | @item softvfp | |
16971 | Software FPU with pure-endian doubles. | |
16972 | @item vfp | |
16973 | VFP co-processor. | |
16974 | @end table | |
16975 | ||
16976 | @item show arm fpu | |
16977 | Show the current type of the FPU. | |
16978 | ||
16979 | @item set arm abi | |
16980 | This command forces @value{GDBN} to use the specified ABI. | |
16981 | ||
16982 | @item show arm abi | |
16983 | Show the currently used ABI. | |
16984 | ||
0428b8f5 DJ |
16985 | @item set arm fallback-mode (arm|thumb|auto) |
16986 | @value{GDBN} uses the symbol table, when available, to determine | |
16987 | whether instructions are ARM or Thumb. This command controls | |
16988 | @value{GDBN}'s default behavior when the symbol table is not | |
16989 | available. The default is @samp{auto}, which causes @value{GDBN} to | |
16990 | use the current execution mode (from the @code{T} bit in the @code{CPSR} | |
16991 | register). | |
16992 | ||
16993 | @item show arm fallback-mode | |
16994 | Show the current fallback instruction mode. | |
16995 | ||
16996 | @item set arm force-mode (arm|thumb|auto) | |
16997 | This command overrides use of the symbol table to determine whether | |
16998 | instructions are ARM or Thumb. The default is @samp{auto}, which | |
16999 | causes @value{GDBN} to use the symbol table and then the setting | |
17000 | of @samp{set arm fallback-mode}. | |
17001 | ||
17002 | @item show arm force-mode | |
17003 | Show the current forced instruction mode. | |
17004 | ||
e2f4edfd EZ |
17005 | @item set debug arm |
17006 | Toggle whether to display ARM-specific debugging messages from the ARM | |
17007 | target support subsystem. | |
17008 | ||
17009 | @item show debug arm | |
17010 | Show whether ARM-specific debugging messages are enabled. | |
17011 | @end table | |
17012 | ||
c45da7e6 EZ |
17013 | The following commands are available when an ARM target is debugged |
17014 | using the RDI interface: | |
17015 | ||
17016 | @table @code | |
17017 | @item rdilogfile @r{[}@var{file}@r{]} | |
17018 | @kindex rdilogfile | |
17019 | @cindex ADP (Angel Debugger Protocol) logging | |
17020 | Set the filename for the ADP (Angel Debugger Protocol) packet log. | |
17021 | With an argument, sets the log file to the specified @var{file}. With | |
17022 | no argument, show the current log file name. The default log file is | |
17023 | @file{rdi.log}. | |
17024 | ||
17025 | @item rdilogenable @r{[}@var{arg}@r{]} | |
17026 | @kindex rdilogenable | |
17027 | Control logging of ADP packets. With an argument of 1 or @code{"yes"} | |
17028 | enables logging, with an argument 0 or @code{"no"} disables it. With | |
17029 | no arguments displays the current setting. When logging is enabled, | |
17030 | ADP packets exchanged between @value{GDBN} and the RDI target device | |
17031 | are logged to a file. | |
17032 | ||
17033 | @item set rdiromatzero | |
17034 | @kindex set rdiromatzero | |
17035 | @cindex ROM at zero address, RDI | |
17036 | Tell @value{GDBN} whether the target has ROM at address 0. If on, | |
17037 | vector catching is disabled, so that zero address can be used. If off | |
17038 | (the default), vector catching is enabled. For this command to take | |
17039 | effect, it needs to be invoked prior to the @code{target rdi} command. | |
17040 | ||
17041 | @item show rdiromatzero | |
17042 | @kindex show rdiromatzero | |
17043 | Show the current setting of ROM at zero address. | |
17044 | ||
17045 | @item set rdiheartbeat | |
17046 | @kindex set rdiheartbeat | |
17047 | @cindex RDI heartbeat | |
17048 | Enable or disable RDI heartbeat packets. It is not recommended to | |
17049 | turn on this option, since it confuses ARM and EPI JTAG interface, as | |
17050 | well as the Angel monitor. | |
17051 | ||
17052 | @item show rdiheartbeat | |
17053 | @kindex show rdiheartbeat | |
17054 | Show the setting of RDI heartbeat packets. | |
17055 | @end table | |
17056 | ||
e2f4edfd | 17057 | |
8e04817f | 17058 | @node M32R/D |
ba04e063 | 17059 | @subsection Renesas M32R/D and M32R/SDI |
8e04817f AC |
17060 | |
17061 | @table @code | |
8e04817f AC |
17062 | @kindex target m32r |
17063 | @item target m32r @var{dev} | |
172c2a43 | 17064 | Renesas M32R/D ROM monitor. |
8e04817f | 17065 | |
fb3e19c0 KI |
17066 | @kindex target m32rsdi |
17067 | @item target m32rsdi @var{dev} | |
17068 | Renesas M32R SDI server, connected via parallel port to the board. | |
721c2651 EZ |
17069 | @end table |
17070 | ||
17071 | The following @value{GDBN} commands are specific to the M32R monitor: | |
17072 | ||
17073 | @table @code | |
17074 | @item set download-path @var{path} | |
17075 | @kindex set download-path | |
17076 | @cindex find downloadable @sc{srec} files (M32R) | |
d3e8051b | 17077 | Set the default path for finding downloadable @sc{srec} files. |
721c2651 EZ |
17078 | |
17079 | @item show download-path | |
17080 | @kindex show download-path | |
17081 | Show the default path for downloadable @sc{srec} files. | |
fb3e19c0 | 17082 | |
721c2651 EZ |
17083 | @item set board-address @var{addr} |
17084 | @kindex set board-address | |
17085 | @cindex M32-EVA target board address | |
17086 | Set the IP address for the M32R-EVA target board. | |
17087 | ||
17088 | @item show board-address | |
17089 | @kindex show board-address | |
17090 | Show the current IP address of the target board. | |
17091 | ||
17092 | @item set server-address @var{addr} | |
17093 | @kindex set server-address | |
17094 | @cindex download server address (M32R) | |
17095 | Set the IP address for the download server, which is the @value{GDBN}'s | |
17096 | host machine. | |
17097 | ||
17098 | @item show server-address | |
17099 | @kindex show server-address | |
17100 | Display the IP address of the download server. | |
17101 | ||
17102 | @item upload @r{[}@var{file}@r{]} | |
17103 | @kindex upload@r{, M32R} | |
17104 | Upload the specified @sc{srec} @var{file} via the monitor's Ethernet | |
17105 | upload capability. If no @var{file} argument is given, the current | |
17106 | executable file is uploaded. | |
17107 | ||
17108 | @item tload @r{[}@var{file}@r{]} | |
17109 | @kindex tload@r{, M32R} | |
17110 | Test the @code{upload} command. | |
8e04817f AC |
17111 | @end table |
17112 | ||
ba04e063 EZ |
17113 | The following commands are available for M32R/SDI: |
17114 | ||
17115 | @table @code | |
17116 | @item sdireset | |
17117 | @kindex sdireset | |
17118 | @cindex reset SDI connection, M32R | |
17119 | This command resets the SDI connection. | |
17120 | ||
17121 | @item sdistatus | |
17122 | @kindex sdistatus | |
17123 | This command shows the SDI connection status. | |
17124 | ||
17125 | @item debug_chaos | |
17126 | @kindex debug_chaos | |
17127 | @cindex M32R/Chaos debugging | |
17128 | Instructs the remote that M32R/Chaos debugging is to be used. | |
17129 | ||
17130 | @item use_debug_dma | |
17131 | @kindex use_debug_dma | |
17132 | Instructs the remote to use the DEBUG_DMA method of accessing memory. | |
17133 | ||
17134 | @item use_mon_code | |
17135 | @kindex use_mon_code | |
17136 | Instructs the remote to use the MON_CODE method of accessing memory. | |
17137 | ||
17138 | @item use_ib_break | |
17139 | @kindex use_ib_break | |
17140 | Instructs the remote to set breakpoints by IB break. | |
17141 | ||
17142 | @item use_dbt_break | |
17143 | @kindex use_dbt_break | |
17144 | Instructs the remote to set breakpoints by DBT. | |
17145 | @end table | |
17146 | ||
8e04817f AC |
17147 | @node M68K |
17148 | @subsection M68k | |
17149 | ||
7ce59000 DJ |
17150 | The Motorola m68k configuration includes ColdFire support, and a |
17151 | target command for the following ROM monitor. | |
8e04817f AC |
17152 | |
17153 | @table @code | |
17154 | ||
8e04817f AC |
17155 | @kindex target dbug |
17156 | @item target dbug @var{dev} | |
17157 | dBUG ROM monitor for Motorola ColdFire. | |
17158 | ||
8e04817f AC |
17159 | @end table |
17160 | ||
08be9d71 ME |
17161 | @node MicroBlaze |
17162 | @subsection MicroBlaze | |
17163 | @cindex Xilinx MicroBlaze | |
17164 | @cindex XMD, Xilinx Microprocessor Debugger | |
17165 | ||
17166 | The MicroBlaze is a soft-core processor supported on various Xilinx | |
17167 | FPGAs, such as Spartan or Virtex series. Boards with these processors | |
17168 | usually have JTAG ports which connect to a host system running the Xilinx | |
17169 | Embedded Development Kit (EDK) or Software Development Kit (SDK). | |
17170 | This host system is used to download the configuration bitstream to | |
17171 | the target FPGA. The Xilinx Microprocessor Debugger (XMD) program | |
17172 | communicates with the target board using the JTAG interface and | |
17173 | presents a @code{gdbserver} interface to the board. By default | |
17174 | @code{xmd} uses port @code{1234}. (While it is possible to change | |
17175 | this default port, it requires the use of undocumented @code{xmd} | |
17176 | commands. Contact Xilinx support if you need to do this.) | |
17177 | ||
17178 | Use these GDB commands to connect to the MicroBlaze target processor. | |
17179 | ||
17180 | @table @code | |
17181 | @item target remote :1234 | |
17182 | Use this command to connect to the target if you are running @value{GDBN} | |
17183 | on the same system as @code{xmd}. | |
17184 | ||
17185 | @item target remote @var{xmd-host}:1234 | |
17186 | Use this command to connect to the target if it is connected to @code{xmd} | |
17187 | running on a different system named @var{xmd-host}. | |
17188 | ||
17189 | @item load | |
17190 | Use this command to download a program to the MicroBlaze target. | |
17191 | ||
17192 | @item set debug microblaze @var{n} | |
17193 | Enable MicroBlaze-specific debugging messages if non-zero. | |
17194 | ||
17195 | @item show debug microblaze @var{n} | |
17196 | Show MicroBlaze-specific debugging level. | |
17197 | @end table | |
17198 | ||
8e04817f AC |
17199 | @node MIPS Embedded |
17200 | @subsection MIPS Embedded | |
17201 | ||
17202 | @cindex MIPS boards | |
17203 | @value{GDBN} can use the MIPS remote debugging protocol to talk to a | |
17204 | MIPS board attached to a serial line. This is available when | |
17205 | you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}. | |
104c1213 | 17206 | |
8e04817f AC |
17207 | @need 1000 |
17208 | Use these @value{GDBN} commands to specify the connection to your target board: | |
104c1213 | 17209 | |
8e04817f AC |
17210 | @table @code |
17211 | @item target mips @var{port} | |
17212 | @kindex target mips @var{port} | |
17213 | To run a program on the board, start up @code{@value{GDBP}} with the | |
17214 | name of your program as the argument. To connect to the board, use the | |
17215 | command @samp{target mips @var{port}}, where @var{port} is the name of | |
17216 | the serial port connected to the board. If the program has not already | |
17217 | been downloaded to the board, you may use the @code{load} command to | |
17218 | download it. You can then use all the usual @value{GDBN} commands. | |
104c1213 | 17219 | |
8e04817f AC |
17220 | For example, this sequence connects to the target board through a serial |
17221 | port, and loads and runs a program called @var{prog} through the | |
17222 | debugger: | |
104c1213 | 17223 | |
474c8240 | 17224 | @smallexample |
8e04817f AC |
17225 | host$ @value{GDBP} @var{prog} |
17226 | @value{GDBN} is free software and @dots{} | |
17227 | (@value{GDBP}) target mips /dev/ttyb | |
17228 | (@value{GDBP}) load @var{prog} | |
17229 | (@value{GDBP}) run | |
474c8240 | 17230 | @end smallexample |
104c1213 | 17231 | |
8e04817f AC |
17232 | @item target mips @var{hostname}:@var{portnumber} |
17233 | On some @value{GDBN} host configurations, you can specify a TCP | |
17234 | connection (for instance, to a serial line managed by a terminal | |
17235 | concentrator) instead of a serial port, using the syntax | |
17236 | @samp{@var{hostname}:@var{portnumber}}. | |
104c1213 | 17237 | |
8e04817f AC |
17238 | @item target pmon @var{port} |
17239 | @kindex target pmon @var{port} | |
17240 | PMON ROM monitor. | |
104c1213 | 17241 | |
8e04817f AC |
17242 | @item target ddb @var{port} |
17243 | @kindex target ddb @var{port} | |
17244 | NEC's DDB variant of PMON for Vr4300. | |
104c1213 | 17245 | |
8e04817f AC |
17246 | @item target lsi @var{port} |
17247 | @kindex target lsi @var{port} | |
17248 | LSI variant of PMON. | |
104c1213 | 17249 | |
8e04817f AC |
17250 | @kindex target r3900 |
17251 | @item target r3900 @var{dev} | |
17252 | Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips. | |
104c1213 | 17253 | |
8e04817f AC |
17254 | @kindex target array |
17255 | @item target array @var{dev} | |
17256 | Array Tech LSI33K RAID controller board. | |
104c1213 | 17257 | |
8e04817f | 17258 | @end table |
104c1213 | 17259 | |
104c1213 | 17260 | |
8e04817f AC |
17261 | @noindent |
17262 | @value{GDBN} also supports these special commands for MIPS targets: | |
104c1213 | 17263 | |
8e04817f | 17264 | @table @code |
8e04817f AC |
17265 | @item set mipsfpu double |
17266 | @itemx set mipsfpu single | |
17267 | @itemx set mipsfpu none | |
a64548ea | 17268 | @itemx set mipsfpu auto |
8e04817f AC |
17269 | @itemx show mipsfpu |
17270 | @kindex set mipsfpu | |
17271 | @kindex show mipsfpu | |
17272 | @cindex MIPS remote floating point | |
17273 | @cindex floating point, MIPS remote | |
17274 | If your target board does not support the MIPS floating point | |
17275 | coprocessor, you should use the command @samp{set mipsfpu none} (if you | |
17276 | need this, you may wish to put the command in your @value{GDBN} init | |
17277 | file). This tells @value{GDBN} how to find the return value of | |
17278 | functions which return floating point values. It also allows | |
17279 | @value{GDBN} to avoid saving the floating point registers when calling | |
17280 | functions on the board. If you are using a floating point coprocessor | |
17281 | with only single precision floating point support, as on the @sc{r4650} | |
17282 | processor, use the command @samp{set mipsfpu single}. The default | |
17283 | double precision floating point coprocessor may be selected using | |
17284 | @samp{set mipsfpu double}. | |
104c1213 | 17285 | |
8e04817f AC |
17286 | In previous versions the only choices were double precision or no |
17287 | floating point, so @samp{set mipsfpu on} will select double precision | |
17288 | and @samp{set mipsfpu off} will select no floating point. | |
104c1213 | 17289 | |
8e04817f AC |
17290 | As usual, you can inquire about the @code{mipsfpu} variable with |
17291 | @samp{show mipsfpu}. | |
104c1213 | 17292 | |
8e04817f AC |
17293 | @item set timeout @var{seconds} |
17294 | @itemx set retransmit-timeout @var{seconds} | |
17295 | @itemx show timeout | |
17296 | @itemx show retransmit-timeout | |
17297 | @cindex @code{timeout}, MIPS protocol | |
17298 | @cindex @code{retransmit-timeout}, MIPS protocol | |
17299 | @kindex set timeout | |
17300 | @kindex show timeout | |
17301 | @kindex set retransmit-timeout | |
17302 | @kindex show retransmit-timeout | |
17303 | You can control the timeout used while waiting for a packet, in the MIPS | |
17304 | remote protocol, with the @code{set timeout @var{seconds}} command. The | |
17305 | default is 5 seconds. Similarly, you can control the timeout used while | |
a6f3e723 | 17306 | waiting for an acknowledgment of a packet with the @code{set |
8e04817f AC |
17307 | retransmit-timeout @var{seconds}} command. The default is 3 seconds. |
17308 | You can inspect both values with @code{show timeout} and @code{show | |
17309 | retransmit-timeout}. (These commands are @emph{only} available when | |
17310 | @value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.) | |
104c1213 | 17311 | |
8e04817f AC |
17312 | The timeout set by @code{set timeout} does not apply when @value{GDBN} |
17313 | is waiting for your program to stop. In that case, @value{GDBN} waits | |
17314 | forever because it has no way of knowing how long the program is going | |
17315 | to run before stopping. | |
ba04e063 EZ |
17316 | |
17317 | @item set syn-garbage-limit @var{num} | |
17318 | @kindex set syn-garbage-limit@r{, MIPS remote} | |
17319 | @cindex synchronize with remote MIPS target | |
17320 | Limit the maximum number of characters @value{GDBN} should ignore when | |
17321 | it tries to synchronize with the remote target. The default is 10 | |
17322 | characters. Setting the limit to -1 means there's no limit. | |
17323 | ||
17324 | @item show syn-garbage-limit | |
17325 | @kindex show syn-garbage-limit@r{, MIPS remote} | |
17326 | Show the current limit on the number of characters to ignore when | |
17327 | trying to synchronize with the remote system. | |
17328 | ||
17329 | @item set monitor-prompt @var{prompt} | |
17330 | @kindex set monitor-prompt@r{, MIPS remote} | |
17331 | @cindex remote monitor prompt | |
17332 | Tell @value{GDBN} to expect the specified @var{prompt} string from the | |
17333 | remote monitor. The default depends on the target: | |
17334 | @table @asis | |
17335 | @item pmon target | |
17336 | @samp{PMON} | |
17337 | @item ddb target | |
17338 | @samp{NEC010} | |
17339 | @item lsi target | |
17340 | @samp{PMON>} | |
17341 | @end table | |
17342 | ||
17343 | @item show monitor-prompt | |
17344 | @kindex show monitor-prompt@r{, MIPS remote} | |
17345 | Show the current strings @value{GDBN} expects as the prompt from the | |
17346 | remote monitor. | |
17347 | ||
17348 | @item set monitor-warnings | |
17349 | @kindex set monitor-warnings@r{, MIPS remote} | |
17350 | Enable or disable monitor warnings about hardware breakpoints. This | |
17351 | has effect only for the @code{lsi} target. When on, @value{GDBN} will | |
17352 | display warning messages whose codes are returned by the @code{lsi} | |
17353 | PMON monitor for breakpoint commands. | |
17354 | ||
17355 | @item show monitor-warnings | |
17356 | @kindex show monitor-warnings@r{, MIPS remote} | |
17357 | Show the current setting of printing monitor warnings. | |
17358 | ||
17359 | @item pmon @var{command} | |
17360 | @kindex pmon@r{, MIPS remote} | |
17361 | @cindex send PMON command | |
17362 | This command allows sending an arbitrary @var{command} string to the | |
17363 | monitor. The monitor must be in debug mode for this to work. | |
8e04817f | 17364 | @end table |
104c1213 | 17365 | |
a37295f9 MM |
17366 | @node OpenRISC 1000 |
17367 | @subsection OpenRISC 1000 | |
17368 | @cindex OpenRISC 1000 | |
17369 | ||
17370 | @cindex or1k boards | |
17371 | See OR1k Architecture document (@uref{www.opencores.org}) for more information | |
17372 | about platform and commands. | |
17373 | ||
17374 | @table @code | |
17375 | ||
17376 | @kindex target jtag | |
17377 | @item target jtag jtag://@var{host}:@var{port} | |
17378 | ||
17379 | Connects to remote JTAG server. | |
17380 | JTAG remote server can be either an or1ksim or JTAG server, | |
17381 | connected via parallel port to the board. | |
17382 | ||
17383 | Example: @code{target jtag jtag://localhost:9999} | |
17384 | ||
17385 | @kindex or1ksim | |
17386 | @item or1ksim @var{command} | |
17387 | If connected to @code{or1ksim} OpenRISC 1000 Architectural | |
17388 | Simulator, proprietary commands can be executed. | |
17389 | ||
17390 | @kindex info or1k spr | |
17391 | @item info or1k spr | |
17392 | Displays spr groups. | |
17393 | ||
17394 | @item info or1k spr @var{group} | |
17395 | @itemx info or1k spr @var{groupno} | |
17396 | Displays register names in selected group. | |
17397 | ||
17398 | @item info or1k spr @var{group} @var{register} | |
17399 | @itemx info or1k spr @var{register} | |
17400 | @itemx info or1k spr @var{groupno} @var{registerno} | |
17401 | @itemx info or1k spr @var{registerno} | |
17402 | Shows information about specified spr register. | |
17403 | ||
17404 | @kindex spr | |
17405 | @item spr @var{group} @var{register} @var{value} | |
17406 | @itemx spr @var{register @var{value}} | |
17407 | @itemx spr @var{groupno} @var{registerno @var{value}} | |
17408 | @itemx spr @var{registerno @var{value}} | |
17409 | Writes @var{value} to specified spr register. | |
17410 | @end table | |
17411 | ||
17412 | Some implementations of OpenRISC 1000 Architecture also have hardware trace. | |
17413 | It is very similar to @value{GDBN} trace, except it does not interfere with normal | |
17414 | program execution and is thus much faster. Hardware breakpoints/watchpoint | |
17415 | triggers can be set using: | |
17416 | @table @code | |
17417 | @item $LEA/$LDATA | |
17418 | Load effective address/data | |
17419 | @item $SEA/$SDATA | |
17420 | Store effective address/data | |
17421 | @item $AEA/$ADATA | |
17422 | Access effective address ($SEA or $LEA) or data ($SDATA/$LDATA) | |
17423 | @item $FETCH | |
17424 | Fetch data | |
17425 | @end table | |
17426 | ||
17427 | When triggered, it can capture low level data, like: @code{PC}, @code{LSEA}, | |
17428 | @code{LDATA}, @code{SDATA}, @code{READSPR}, @code{WRITESPR}, @code{INSTR}. | |
17429 | ||
17430 | @code{htrace} commands: | |
17431 | @cindex OpenRISC 1000 htrace | |
17432 | @table @code | |
17433 | @kindex hwatch | |
17434 | @item hwatch @var{conditional} | |
d3e8051b | 17435 | Set hardware watchpoint on combination of Load/Store Effective Address(es) |
a37295f9 MM |
17436 | or Data. For example: |
17437 | ||
17438 | @code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)} | |
17439 | ||
17440 | @code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)} | |
17441 | ||
4644b6e3 | 17442 | @kindex htrace |
a37295f9 MM |
17443 | @item htrace info |
17444 | Display information about current HW trace configuration. | |
17445 | ||
a37295f9 MM |
17446 | @item htrace trigger @var{conditional} |
17447 | Set starting criteria for HW trace. | |
17448 | ||
a37295f9 MM |
17449 | @item htrace qualifier @var{conditional} |
17450 | Set acquisition qualifier for HW trace. | |
17451 | ||
a37295f9 MM |
17452 | @item htrace stop @var{conditional} |
17453 | Set HW trace stopping criteria. | |
17454 | ||
f153cc92 | 17455 | @item htrace record [@var{data}]* |
a37295f9 MM |
17456 | Selects the data to be recorded, when qualifier is met and HW trace was |
17457 | triggered. | |
17458 | ||
a37295f9 | 17459 | @item htrace enable |
a37295f9 MM |
17460 | @itemx htrace disable |
17461 | Enables/disables the HW trace. | |
17462 | ||
f153cc92 | 17463 | @item htrace rewind [@var{filename}] |
a37295f9 MM |
17464 | Clears currently recorded trace data. |
17465 | ||
17466 | If filename is specified, new trace file is made and any newly collected data | |
17467 | will be written there. | |
17468 | ||
f153cc92 | 17469 | @item htrace print [@var{start} [@var{len}]] |
a37295f9 MM |
17470 | Prints trace buffer, using current record configuration. |
17471 | ||
a37295f9 MM |
17472 | @item htrace mode continuous |
17473 | Set continuous trace mode. | |
17474 | ||
a37295f9 MM |
17475 | @item htrace mode suspend |
17476 | Set suspend trace mode. | |
17477 | ||
17478 | @end table | |
17479 | ||
4acd40f3 TJB |
17480 | @node PowerPC Embedded |
17481 | @subsection PowerPC Embedded | |
104c1213 | 17482 | |
55eddb0f DJ |
17483 | @value{GDBN} provides the following PowerPC-specific commands: |
17484 | ||
104c1213 | 17485 | @table @code |
55eddb0f DJ |
17486 | @kindex set powerpc |
17487 | @item set powerpc soft-float | |
17488 | @itemx show powerpc soft-float | |
17489 | Force @value{GDBN} to use (or not use) a software floating point calling | |
17490 | convention. By default, @value{GDBN} selects the calling convention based | |
17491 | on the selected architecture and the provided executable file. | |
17492 | ||
17493 | @item set powerpc vector-abi | |
17494 | @itemx show powerpc vector-abi | |
17495 | Force @value{GDBN} to use the specified calling convention for vector | |
17496 | arguments and return values. The valid options are @samp{auto}; | |
17497 | @samp{generic}, to avoid vector registers even if they are present; | |
17498 | @samp{altivec}, to use AltiVec registers; and @samp{spe} to use SPE | |
17499 | registers. By default, @value{GDBN} selects the calling convention | |
17500 | based on the selected architecture and the provided executable file. | |
17501 | ||
8e04817f AC |
17502 | @kindex target dink32 |
17503 | @item target dink32 @var{dev} | |
17504 | DINK32 ROM monitor. | |
104c1213 | 17505 | |
8e04817f AC |
17506 | @kindex target ppcbug |
17507 | @item target ppcbug @var{dev} | |
17508 | @kindex target ppcbug1 | |
17509 | @item target ppcbug1 @var{dev} | |
17510 | PPCBUG ROM monitor for PowerPC. | |
104c1213 | 17511 | |
8e04817f AC |
17512 | @kindex target sds |
17513 | @item target sds @var{dev} | |
17514 | SDS monitor, running on a PowerPC board (such as Motorola's ADS). | |
c45da7e6 | 17515 | @end table |
8e04817f | 17516 | |
c45da7e6 | 17517 | @cindex SDS protocol |
d52fb0e9 | 17518 | The following commands specific to the SDS protocol are supported |
55eddb0f | 17519 | by @value{GDBN}: |
c45da7e6 EZ |
17520 | |
17521 | @table @code | |
17522 | @item set sdstimeout @var{nsec} | |
17523 | @kindex set sdstimeout | |
17524 | Set the timeout for SDS protocol reads to be @var{nsec} seconds. The | |
17525 | default is 2 seconds. | |
17526 | ||
17527 | @item show sdstimeout | |
17528 | @kindex show sdstimeout | |
17529 | Show the current value of the SDS timeout. | |
17530 | ||
17531 | @item sds @var{command} | |
17532 | @kindex sds@r{, a command} | |
17533 | Send the specified @var{command} string to the SDS monitor. | |
8e04817f AC |
17534 | @end table |
17535 | ||
c45da7e6 | 17536 | |
8e04817f AC |
17537 | @node PA |
17538 | @subsection HP PA Embedded | |
104c1213 JM |
17539 | |
17540 | @table @code | |
17541 | ||
8e04817f AC |
17542 | @kindex target op50n |
17543 | @item target op50n @var{dev} | |
17544 | OP50N monitor, running on an OKI HPPA board. | |
17545 | ||
17546 | @kindex target w89k | |
17547 | @item target w89k @var{dev} | |
17548 | W89K monitor, running on a Winbond HPPA board. | |
104c1213 JM |
17549 | |
17550 | @end table | |
17551 | ||
8e04817f AC |
17552 | @node Sparclet |
17553 | @subsection Tsqware Sparclet | |
104c1213 | 17554 | |
8e04817f AC |
17555 | @cindex Sparclet |
17556 | ||
17557 | @value{GDBN} enables developers to debug tasks running on | |
17558 | Sparclet targets from a Unix host. | |
17559 | @value{GDBN} uses code that runs on | |
17560 | both the Unix host and on the Sparclet target. The program | |
17561 | @code{@value{GDBP}} is installed and executed on the Unix host. | |
104c1213 | 17562 | |
8e04817f AC |
17563 | @table @code |
17564 | @item remotetimeout @var{args} | |
17565 | @kindex remotetimeout | |
17566 | @value{GDBN} supports the option @code{remotetimeout}. | |
17567 | This option is set by the user, and @var{args} represents the number of | |
17568 | seconds @value{GDBN} waits for responses. | |
104c1213 JM |
17569 | @end table |
17570 | ||
8e04817f AC |
17571 | @cindex compiling, on Sparclet |
17572 | When compiling for debugging, include the options @samp{-g} to get debug | |
17573 | information and @samp{-Ttext} to relocate the program to where you wish to | |
17574 | load it on the target. You may also want to add the options @samp{-n} or | |
17575 | @samp{-N} in order to reduce the size of the sections. Example: | |
104c1213 | 17576 | |
474c8240 | 17577 | @smallexample |
8e04817f | 17578 | sparclet-aout-gcc prog.c -Ttext 0x12010000 -g -o prog -N |
474c8240 | 17579 | @end smallexample |
104c1213 | 17580 | |
8e04817f | 17581 | You can use @code{objdump} to verify that the addresses are what you intended: |
104c1213 | 17582 | |
474c8240 | 17583 | @smallexample |
8e04817f | 17584 | sparclet-aout-objdump --headers --syms prog |
474c8240 | 17585 | @end smallexample |
104c1213 | 17586 | |
8e04817f AC |
17587 | @cindex running, on Sparclet |
17588 | Once you have set | |
17589 | your Unix execution search path to find @value{GDBN}, you are ready to | |
17590 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} | |
17591 | (or @code{sparclet-aout-gdb}, depending on your installation). | |
104c1213 | 17592 | |
8e04817f AC |
17593 | @value{GDBN} comes up showing the prompt: |
17594 | ||
474c8240 | 17595 | @smallexample |
8e04817f | 17596 | (gdbslet) |
474c8240 | 17597 | @end smallexample |
104c1213 JM |
17598 | |
17599 | @menu | |
8e04817f AC |
17600 | * Sparclet File:: Setting the file to debug |
17601 | * Sparclet Connection:: Connecting to Sparclet | |
17602 | * Sparclet Download:: Sparclet download | |
17603 | * Sparclet Execution:: Running and debugging | |
104c1213 JM |
17604 | @end menu |
17605 | ||
8e04817f | 17606 | @node Sparclet File |
79a6e687 | 17607 | @subsubsection Setting File to Debug |
104c1213 | 17608 | |
8e04817f | 17609 | The @value{GDBN} command @code{file} lets you choose with program to debug. |
104c1213 | 17610 | |
474c8240 | 17611 | @smallexample |
8e04817f | 17612 | (gdbslet) file prog |
474c8240 | 17613 | @end smallexample |
104c1213 | 17614 | |
8e04817f AC |
17615 | @need 1000 |
17616 | @value{GDBN} then attempts to read the symbol table of @file{prog}. | |
17617 | @value{GDBN} locates | |
17618 | the file by searching the directories listed in the command search | |
17619 | path. | |
12c27660 | 17620 | If the file was compiled with debug information (option @samp{-g}), source |
8e04817f AC |
17621 | files will be searched as well. |
17622 | @value{GDBN} locates | |
17623 | the source files by searching the directories listed in the directory search | |
79a6e687 | 17624 | path (@pxref{Environment, ,Your Program's Environment}). |
8e04817f AC |
17625 | If it fails |
17626 | to find a file, it displays a message such as: | |
104c1213 | 17627 | |
474c8240 | 17628 | @smallexample |
8e04817f | 17629 | prog: No such file or directory. |
474c8240 | 17630 | @end smallexample |
104c1213 | 17631 | |
8e04817f AC |
17632 | When this happens, add the appropriate directories to the search paths with |
17633 | the @value{GDBN} commands @code{path} and @code{dir}, and execute the | |
17634 | @code{target} command again. | |
104c1213 | 17635 | |
8e04817f AC |
17636 | @node Sparclet Connection |
17637 | @subsubsection Connecting to Sparclet | |
104c1213 | 17638 | |
8e04817f AC |
17639 | The @value{GDBN} command @code{target} lets you connect to a Sparclet target. |
17640 | To connect to a target on serial port ``@code{ttya}'', type: | |
104c1213 | 17641 | |
474c8240 | 17642 | @smallexample |
8e04817f AC |
17643 | (gdbslet) target sparclet /dev/ttya |
17644 | Remote target sparclet connected to /dev/ttya | |
17645 | main () at ../prog.c:3 | |
474c8240 | 17646 | @end smallexample |
104c1213 | 17647 | |
8e04817f AC |
17648 | @need 750 |
17649 | @value{GDBN} displays messages like these: | |
104c1213 | 17650 | |
474c8240 | 17651 | @smallexample |
8e04817f | 17652 | Connected to ttya. |
474c8240 | 17653 | @end smallexample |
104c1213 | 17654 | |
8e04817f | 17655 | @node Sparclet Download |
79a6e687 | 17656 | @subsubsection Sparclet Download |
104c1213 | 17657 | |
8e04817f AC |
17658 | @cindex download to Sparclet |
17659 | Once connected to the Sparclet target, | |
17660 | you can use the @value{GDBN} | |
17661 | @code{load} command to download the file from the host to the target. | |
17662 | The file name and load offset should be given as arguments to the @code{load} | |
17663 | command. | |
17664 | Since the file format is aout, the program must be loaded to the starting | |
17665 | address. You can use @code{objdump} to find out what this value is. The load | |
17666 | offset is an offset which is added to the VMA (virtual memory address) | |
17667 | of each of the file's sections. | |
17668 | For instance, if the program | |
17669 | @file{prog} was linked to text address 0x1201000, with data at 0x12010160 | |
17670 | and bss at 0x12010170, in @value{GDBN}, type: | |
104c1213 | 17671 | |
474c8240 | 17672 | @smallexample |
8e04817f AC |
17673 | (gdbslet) load prog 0x12010000 |
17674 | Loading section .text, size 0xdb0 vma 0x12010000 | |
474c8240 | 17675 | @end smallexample |
104c1213 | 17676 | |
8e04817f AC |
17677 | If the code is loaded at a different address then what the program was linked |
17678 | to, you may need to use the @code{section} and @code{add-symbol-file} commands | |
17679 | to tell @value{GDBN} where to map the symbol table. | |
17680 | ||
17681 | @node Sparclet Execution | |
79a6e687 | 17682 | @subsubsection Running and Debugging |
8e04817f AC |
17683 | |
17684 | @cindex running and debugging Sparclet programs | |
17685 | You can now begin debugging the task using @value{GDBN}'s execution control | |
17686 | commands, @code{b}, @code{step}, @code{run}, etc. See the @value{GDBN} | |
17687 | manual for the list of commands. | |
17688 | ||
474c8240 | 17689 | @smallexample |
8e04817f AC |
17690 | (gdbslet) b main |
17691 | Breakpoint 1 at 0x12010000: file prog.c, line 3. | |
17692 | (gdbslet) run | |
17693 | Starting program: prog | |
17694 | Breakpoint 1, main (argc=1, argv=0xeffff21c) at prog.c:3 | |
17695 | 3 char *symarg = 0; | |
17696 | (gdbslet) step | |
17697 | 4 char *execarg = "hello!"; | |
17698 | (gdbslet) | |
474c8240 | 17699 | @end smallexample |
8e04817f AC |
17700 | |
17701 | @node Sparclite | |
17702 | @subsection Fujitsu Sparclite | |
104c1213 JM |
17703 | |
17704 | @table @code | |
17705 | ||
8e04817f AC |
17706 | @kindex target sparclite |
17707 | @item target sparclite @var{dev} | |
17708 | Fujitsu sparclite boards, used only for the purpose of loading. | |
17709 | You must use an additional command to debug the program. | |
17710 | For example: target remote @var{dev} using @value{GDBN} standard | |
17711 | remote protocol. | |
104c1213 JM |
17712 | |
17713 | @end table | |
17714 | ||
8e04817f AC |
17715 | @node Z8000 |
17716 | @subsection Zilog Z8000 | |
104c1213 | 17717 | |
8e04817f AC |
17718 | @cindex Z8000 |
17719 | @cindex simulator, Z8000 | |
17720 | @cindex Zilog Z8000 simulator | |
104c1213 | 17721 | |
8e04817f AC |
17722 | When configured for debugging Zilog Z8000 targets, @value{GDBN} includes |
17723 | a Z8000 simulator. | |
17724 | ||
17725 | For the Z8000 family, @samp{target sim} simulates either the Z8002 (the | |
17726 | unsegmented variant of the Z8000 architecture) or the Z8001 (the | |
17727 | segmented variant). The simulator recognizes which architecture is | |
17728 | appropriate by inspecting the object code. | |
104c1213 | 17729 | |
8e04817f AC |
17730 | @table @code |
17731 | @item target sim @var{args} | |
17732 | @kindex sim | |
17733 | @kindex target sim@r{, with Z8000} | |
17734 | Debug programs on a simulated CPU. If the simulator supports setup | |
17735 | options, specify them via @var{args}. | |
104c1213 JM |
17736 | @end table |
17737 | ||
8e04817f AC |
17738 | @noindent |
17739 | After specifying this target, you can debug programs for the simulated | |
17740 | CPU in the same style as programs for your host computer; use the | |
17741 | @code{file} command to load a new program image, the @code{run} command | |
17742 | to run your program, and so on. | |
17743 | ||
17744 | As well as making available all the usual machine registers | |
17745 | (@pxref{Registers, ,Registers}), the Z8000 simulator provides three | |
17746 | additional items of information as specially named registers: | |
104c1213 JM |
17747 | |
17748 | @table @code | |
17749 | ||
8e04817f AC |
17750 | @item cycles |
17751 | Counts clock-ticks in the simulator. | |
104c1213 | 17752 | |
8e04817f AC |
17753 | @item insts |
17754 | Counts instructions run in the simulator. | |
104c1213 | 17755 | |
8e04817f AC |
17756 | @item time |
17757 | Execution time in 60ths of a second. | |
104c1213 | 17758 | |
8e04817f | 17759 | @end table |
104c1213 | 17760 | |
8e04817f AC |
17761 | You can refer to these values in @value{GDBN} expressions with the usual |
17762 | conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a | |
17763 | conditional breakpoint that suspends only after at least 5000 | |
17764 | simulated clock ticks. | |
104c1213 | 17765 | |
a64548ea EZ |
17766 | @node AVR |
17767 | @subsection Atmel AVR | |
17768 | @cindex AVR | |
17769 | ||
17770 | When configured for debugging the Atmel AVR, @value{GDBN} supports the | |
17771 | following AVR-specific commands: | |
17772 | ||
17773 | @table @code | |
17774 | @item info io_registers | |
17775 | @kindex info io_registers@r{, AVR} | |
17776 | @cindex I/O registers (Atmel AVR) | |
17777 | This command displays information about the AVR I/O registers. For | |
17778 | each register, @value{GDBN} prints its number and value. | |
17779 | @end table | |
17780 | ||
17781 | @node CRIS | |
17782 | @subsection CRIS | |
17783 | @cindex CRIS | |
17784 | ||
17785 | When configured for debugging CRIS, @value{GDBN} provides the | |
17786 | following CRIS-specific commands: | |
17787 | ||
17788 | @table @code | |
17789 | @item set cris-version @var{ver} | |
17790 | @cindex CRIS version | |
e22e55c9 OF |
17791 | Set the current CRIS version to @var{ver}, either @samp{10} or @samp{32}. |
17792 | The CRIS version affects register names and sizes. This command is useful in | |
17793 | case autodetection of the CRIS version fails. | |
a64548ea EZ |
17794 | |
17795 | @item show cris-version | |
17796 | Show the current CRIS version. | |
17797 | ||
17798 | @item set cris-dwarf2-cfi | |
17799 | @cindex DWARF-2 CFI and CRIS | |
e22e55c9 OF |
17800 | Set the usage of DWARF-2 CFI for CRIS debugging. The default is @samp{on}. |
17801 | Change to @samp{off} when using @code{gcc-cris} whose version is below | |
17802 | @code{R59}. | |
a64548ea EZ |
17803 | |
17804 | @item show cris-dwarf2-cfi | |
17805 | Show the current state of using DWARF-2 CFI. | |
e22e55c9 OF |
17806 | |
17807 | @item set cris-mode @var{mode} | |
17808 | @cindex CRIS mode | |
17809 | Set the current CRIS mode to @var{mode}. It should only be changed when | |
17810 | debugging in guru mode, in which case it should be set to | |
17811 | @samp{guru} (the default is @samp{normal}). | |
17812 | ||
17813 | @item show cris-mode | |
17814 | Show the current CRIS mode. | |
a64548ea EZ |
17815 | @end table |
17816 | ||
17817 | @node Super-H | |
17818 | @subsection Renesas Super-H | |
17819 | @cindex Super-H | |
17820 | ||
17821 | For the Renesas Super-H processor, @value{GDBN} provides these | |
17822 | commands: | |
17823 | ||
17824 | @table @code | |
17825 | @item regs | |
17826 | @kindex regs@r{, Super-H} | |
17827 | Show the values of all Super-H registers. | |
c055b101 CV |
17828 | |
17829 | @item set sh calling-convention @var{convention} | |
17830 | @kindex set sh calling-convention | |
17831 | Set the calling-convention used when calling functions from @value{GDBN}. | |
17832 | Allowed values are @samp{gcc}, which is the default setting, and @samp{renesas}. | |
17833 | With the @samp{gcc} setting, functions are called using the @value{NGCC} calling | |
17834 | convention. If the DWARF-2 information of the called function specifies | |
17835 | that the function follows the Renesas calling convention, the function | |
17836 | is called using the Renesas calling convention. If the calling convention | |
17837 | is set to @samp{renesas}, the Renesas calling convention is always used, | |
17838 | regardless of the DWARF-2 information. This can be used to override the | |
17839 | default of @samp{gcc} if debug information is missing, or the compiler | |
17840 | does not emit the DWARF-2 calling convention entry for a function. | |
17841 | ||
17842 | @item show sh calling-convention | |
17843 | @kindex show sh calling-convention | |
17844 | Show the current calling convention setting. | |
17845 | ||
a64548ea EZ |
17846 | @end table |
17847 | ||
17848 | ||
8e04817f AC |
17849 | @node Architectures |
17850 | @section Architectures | |
104c1213 | 17851 | |
8e04817f AC |
17852 | This section describes characteristics of architectures that affect |
17853 | all uses of @value{GDBN} with the architecture, both native and cross. | |
104c1213 | 17854 | |
8e04817f | 17855 | @menu |
9c16f35a | 17856 | * i386:: |
8e04817f AC |
17857 | * A29K:: |
17858 | * Alpha:: | |
17859 | * MIPS:: | |
a64548ea | 17860 | * HPPA:: HP PA architecture |
23d964e7 | 17861 | * SPU:: Cell Broadband Engine SPU architecture |
4acd40f3 | 17862 | * PowerPC:: |
8e04817f | 17863 | @end menu |
104c1213 | 17864 | |
9c16f35a | 17865 | @node i386 |
db2e3e2e | 17866 | @subsection x86 Architecture-specific Issues |
9c16f35a EZ |
17867 | |
17868 | @table @code | |
17869 | @item set struct-convention @var{mode} | |
17870 | @kindex set struct-convention | |
17871 | @cindex struct return convention | |
17872 | @cindex struct/union returned in registers | |
17873 | Set the convention used by the inferior to return @code{struct}s and | |
17874 | @code{union}s from functions to @var{mode}. Possible values of | |
17875 | @var{mode} are @code{"pcc"}, @code{"reg"}, and @code{"default"} (the | |
17876 | default). @code{"default"} or @code{"pcc"} means that @code{struct}s | |
17877 | are returned on the stack, while @code{"reg"} means that a | |
17878 | @code{struct} or a @code{union} whose size is 1, 2, 4, or 8 bytes will | |
17879 | be returned in a register. | |
17880 | ||
17881 | @item show struct-convention | |
17882 | @kindex show struct-convention | |
17883 | Show the current setting of the convention to return @code{struct}s | |
17884 | from functions. | |
17885 | @end table | |
17886 | ||
8e04817f AC |
17887 | @node A29K |
17888 | @subsection A29K | |
104c1213 JM |
17889 | |
17890 | @table @code | |
104c1213 | 17891 | |
8e04817f AC |
17892 | @kindex set rstack_high_address |
17893 | @cindex AMD 29K register stack | |
17894 | @cindex register stack, AMD29K | |
17895 | @item set rstack_high_address @var{address} | |
17896 | On AMD 29000 family processors, registers are saved in a separate | |
17897 | @dfn{register stack}. There is no way for @value{GDBN} to determine the | |
17898 | extent of this stack. Normally, @value{GDBN} just assumes that the | |
17899 | stack is ``large enough''. This may result in @value{GDBN} referencing | |
17900 | memory locations that do not exist. If necessary, you can get around | |
17901 | this problem by specifying the ending address of the register stack with | |
17902 | the @code{set rstack_high_address} command. The argument should be an | |
17903 | address, which you probably want to precede with @samp{0x} to specify in | |
17904 | hexadecimal. | |
104c1213 | 17905 | |
8e04817f AC |
17906 | @kindex show rstack_high_address |
17907 | @item show rstack_high_address | |
17908 | Display the current limit of the register stack, on AMD 29000 family | |
17909 | processors. | |
104c1213 | 17910 | |
8e04817f | 17911 | @end table |
104c1213 | 17912 | |
8e04817f AC |
17913 | @node Alpha |
17914 | @subsection Alpha | |
104c1213 | 17915 | |
8e04817f | 17916 | See the following section. |
104c1213 | 17917 | |
8e04817f AC |
17918 | @node MIPS |
17919 | @subsection MIPS | |
104c1213 | 17920 | |
8e04817f AC |
17921 | @cindex stack on Alpha |
17922 | @cindex stack on MIPS | |
17923 | @cindex Alpha stack | |
17924 | @cindex MIPS stack | |
17925 | Alpha- and MIPS-based computers use an unusual stack frame, which | |
17926 | sometimes requires @value{GDBN} to search backward in the object code to | |
17927 | find the beginning of a function. | |
104c1213 | 17928 | |
8e04817f AC |
17929 | @cindex response time, MIPS debugging |
17930 | To improve response time (especially for embedded applications, where | |
17931 | @value{GDBN} may be restricted to a slow serial line for this search) | |
17932 | you may want to limit the size of this search, using one of these | |
17933 | commands: | |
104c1213 | 17934 | |
8e04817f AC |
17935 | @table @code |
17936 | @cindex @code{heuristic-fence-post} (Alpha, MIPS) | |
17937 | @item set heuristic-fence-post @var{limit} | |
17938 | Restrict @value{GDBN} to examining at most @var{limit} bytes in its | |
17939 | search for the beginning of a function. A value of @var{0} (the | |
17940 | default) means there is no limit. However, except for @var{0}, the | |
17941 | larger the limit the more bytes @code{heuristic-fence-post} must search | |
e2f4edfd EZ |
17942 | and therefore the longer it takes to run. You should only need to use |
17943 | this command when debugging a stripped executable. | |
104c1213 | 17944 | |
8e04817f AC |
17945 | @item show heuristic-fence-post |
17946 | Display the current limit. | |
17947 | @end table | |
104c1213 JM |
17948 | |
17949 | @noindent | |
8e04817f AC |
17950 | These commands are available @emph{only} when @value{GDBN} is configured |
17951 | for debugging programs on Alpha or MIPS processors. | |
104c1213 | 17952 | |
a64548ea EZ |
17953 | Several MIPS-specific commands are available when debugging MIPS |
17954 | programs: | |
17955 | ||
17956 | @table @code | |
a64548ea EZ |
17957 | @item set mips abi @var{arg} |
17958 | @kindex set mips abi | |
17959 | @cindex set ABI for MIPS | |
17960 | Tell @value{GDBN} which MIPS ABI is used by the inferior. Possible | |
17961 | values of @var{arg} are: | |
17962 | ||
17963 | @table @samp | |
17964 | @item auto | |
17965 | The default ABI associated with the current binary (this is the | |
17966 | default). | |
17967 | @item o32 | |
17968 | @item o64 | |
17969 | @item n32 | |
17970 | @item n64 | |
17971 | @item eabi32 | |
17972 | @item eabi64 | |
17973 | @item auto | |
17974 | @end table | |
17975 | ||
17976 | @item show mips abi | |
17977 | @kindex show mips abi | |
17978 | Show the MIPS ABI used by @value{GDBN} to debug the inferior. | |
17979 | ||
17980 | @item set mipsfpu | |
17981 | @itemx show mipsfpu | |
17982 | @xref{MIPS Embedded, set mipsfpu}. | |
17983 | ||
17984 | @item set mips mask-address @var{arg} | |
17985 | @kindex set mips mask-address | |
17986 | @cindex MIPS addresses, masking | |
17987 | This command determines whether the most-significant 32 bits of 64-bit | |
17988 | MIPS addresses are masked off. The argument @var{arg} can be | |
17989 | @samp{on}, @samp{off}, or @samp{auto}. The latter is the default | |
17990 | setting, which lets @value{GDBN} determine the correct value. | |
17991 | ||
17992 | @item show mips mask-address | |
17993 | @kindex show mips mask-address | |
17994 | Show whether the upper 32 bits of MIPS addresses are masked off or | |
17995 | not. | |
17996 | ||
17997 | @item set remote-mips64-transfers-32bit-regs | |
17998 | @kindex set remote-mips64-transfers-32bit-regs | |
17999 | This command controls compatibility with 64-bit MIPS targets that | |
18000 | transfer data in 32-bit quantities. If you have an old MIPS 64 target | |
18001 | that transfers 32 bits for some registers, like @sc{sr} and @sc{fsr}, | |
18002 | and 64 bits for other registers, set this option to @samp{on}. | |
18003 | ||
18004 | @item show remote-mips64-transfers-32bit-regs | |
18005 | @kindex show remote-mips64-transfers-32bit-regs | |
18006 | Show the current setting of compatibility with older MIPS 64 targets. | |
18007 | ||
18008 | @item set debug mips | |
18009 | @kindex set debug mips | |
18010 | This command turns on and off debugging messages for the MIPS-specific | |
18011 | target code in @value{GDBN}. | |
18012 | ||
18013 | @item show debug mips | |
18014 | @kindex show debug mips | |
18015 | Show the current setting of MIPS debugging messages. | |
18016 | @end table | |
18017 | ||
18018 | ||
18019 | @node HPPA | |
18020 | @subsection HPPA | |
18021 | @cindex HPPA support | |
18022 | ||
d3e8051b | 18023 | When @value{GDBN} is debugging the HP PA architecture, it provides the |
a64548ea EZ |
18024 | following special commands: |
18025 | ||
18026 | @table @code | |
18027 | @item set debug hppa | |
18028 | @kindex set debug hppa | |
db2e3e2e | 18029 | This command determines whether HPPA architecture-specific debugging |
a64548ea EZ |
18030 | messages are to be displayed. |
18031 | ||
18032 | @item show debug hppa | |
18033 | Show whether HPPA debugging messages are displayed. | |
18034 | ||
18035 | @item maint print unwind @var{address} | |
18036 | @kindex maint print unwind@r{, HPPA} | |
18037 | This command displays the contents of the unwind table entry at the | |
18038 | given @var{address}. | |
18039 | ||
18040 | @end table | |
18041 | ||
104c1213 | 18042 | |
23d964e7 UW |
18043 | @node SPU |
18044 | @subsection Cell Broadband Engine SPU architecture | |
18045 | @cindex Cell Broadband Engine | |
18046 | @cindex SPU | |
18047 | ||
18048 | When @value{GDBN} is debugging the Cell Broadband Engine SPU architecture, | |
18049 | it provides the following special commands: | |
18050 | ||
18051 | @table @code | |
18052 | @item info spu event | |
18053 | @kindex info spu | |
18054 | Display SPU event facility status. Shows current event mask | |
18055 | and pending event status. | |
18056 | ||
18057 | @item info spu signal | |
18058 | Display SPU signal notification facility status. Shows pending | |
18059 | signal-control word and signal notification mode of both signal | |
18060 | notification channels. | |
18061 | ||
18062 | @item info spu mailbox | |
18063 | Display SPU mailbox facility status. Shows all pending entries, | |
18064 | in order of processing, in each of the SPU Write Outbound, | |
18065 | SPU Write Outbound Interrupt, and SPU Read Inbound mailboxes. | |
18066 | ||
18067 | @item info spu dma | |
18068 | Display MFC DMA status. Shows all pending commands in the MFC | |
18069 | DMA queue. For each entry, opcode, tag, class IDs, effective | |
18070 | and local store addresses and transfer size are shown. | |
18071 | ||
18072 | @item info spu proxydma | |
18073 | Display MFC Proxy-DMA status. Shows all pending commands in the MFC | |
18074 | Proxy-DMA queue. For each entry, opcode, tag, class IDs, effective | |
18075 | and local store addresses and transfer size are shown. | |
18076 | ||
18077 | @end table | |
18078 | ||
3285f3fe UW |
18079 | When @value{GDBN} is debugging a combined PowerPC/SPU application |
18080 | on the Cell Broadband Engine, it provides in addition the following | |
18081 | special commands: | |
18082 | ||
18083 | @table @code | |
18084 | @item set spu stop-on-load @var{arg} | |
18085 | @kindex set spu | |
18086 | Set whether to stop for new SPE threads. When set to @code{on}, @value{GDBN} | |
18087 | will give control to the user when a new SPE thread enters its @code{main} | |
18088 | function. The default is @code{off}. | |
18089 | ||
18090 | @item show spu stop-on-load | |
18091 | @kindex show spu | |
18092 | Show whether to stop for new SPE threads. | |
18093 | ||
ff1a52c6 UW |
18094 | @item set spu auto-flush-cache @var{arg} |
18095 | Set whether to automatically flush the software-managed cache. When set to | |
18096 | @code{on}, @value{GDBN} will automatically cause the SPE software-managed | |
18097 | cache to be flushed whenever SPE execution stops. This provides a consistent | |
18098 | view of PowerPC memory that is accessed via the cache. If an application | |
18099 | does not use the software-managed cache, this option has no effect. | |
18100 | ||
18101 | @item show spu auto-flush-cache | |
18102 | Show whether to automatically flush the software-managed cache. | |
18103 | ||
3285f3fe UW |
18104 | @end table |
18105 | ||
4acd40f3 TJB |
18106 | @node PowerPC |
18107 | @subsection PowerPC | |
18108 | @cindex PowerPC architecture | |
18109 | ||
18110 | When @value{GDBN} is debugging the PowerPC architecture, it provides a set of | |
18111 | pseudo-registers to enable inspection of 128-bit wide Decimal Floating Point | |
18112 | numbers stored in the floating point registers. These values must be stored | |
18113 | in two consecutive registers, always starting at an even register like | |
18114 | @code{f0} or @code{f2}. | |
18115 | ||
18116 | The pseudo-registers go from @code{$dl0} through @code{$dl15}, and are formed | |
18117 | by joining the even/odd register pairs @code{f0} and @code{f1} for @code{$dl0}, | |
18118 | @code{f2} and @code{f3} for @code{$dl1} and so on. | |
18119 | ||
aeac0ff9 | 18120 | For POWER7 processors, @value{GDBN} provides a set of pseudo-registers, the 64-bit |
677c5bb1 LM |
18121 | wide Extended Floating Point Registers (@samp{f32} through @samp{f63}). |
18122 | ||
23d964e7 | 18123 | |
8e04817f AC |
18124 | @node Controlling GDB |
18125 | @chapter Controlling @value{GDBN} | |
18126 | ||
18127 | You can alter the way @value{GDBN} interacts with you by using the | |
18128 | @code{set} command. For commands controlling how @value{GDBN} displays | |
79a6e687 | 18129 | data, see @ref{Print Settings, ,Print Settings}. Other settings are |
8e04817f AC |
18130 | described here. |
18131 | ||
18132 | @menu | |
18133 | * Prompt:: Prompt | |
18134 | * Editing:: Command editing | |
d620b259 | 18135 | * Command History:: Command history |
8e04817f AC |
18136 | * Screen Size:: Screen size |
18137 | * Numbers:: Numbers | |
1e698235 | 18138 | * ABI:: Configuring the current ABI |
8e04817f AC |
18139 | * Messages/Warnings:: Optional warnings and messages |
18140 | * Debugging Output:: Optional messages about internal happenings | |
14fb1bac | 18141 | * Other Misc Settings:: Other Miscellaneous Settings |
8e04817f AC |
18142 | @end menu |
18143 | ||
18144 | @node Prompt | |
18145 | @section Prompt | |
104c1213 | 18146 | |
8e04817f | 18147 | @cindex prompt |
104c1213 | 18148 | |
8e04817f AC |
18149 | @value{GDBN} indicates its readiness to read a command by printing a string |
18150 | called the @dfn{prompt}. This string is normally @samp{(@value{GDBP})}. You | |
18151 | can change the prompt string with the @code{set prompt} command. For | |
18152 | instance, when debugging @value{GDBN} with @value{GDBN}, it is useful to change | |
18153 | the prompt in one of the @value{GDBN} sessions so that you can always tell | |
18154 | which one you are talking to. | |
104c1213 | 18155 | |
8e04817f AC |
18156 | @emph{Note:} @code{set prompt} does not add a space for you after the |
18157 | prompt you set. This allows you to set a prompt which ends in a space | |
18158 | or a prompt that does not. | |
104c1213 | 18159 | |
8e04817f AC |
18160 | @table @code |
18161 | @kindex set prompt | |
18162 | @item set prompt @var{newprompt} | |
18163 | Directs @value{GDBN} to use @var{newprompt} as its prompt string henceforth. | |
104c1213 | 18164 | |
8e04817f AC |
18165 | @kindex show prompt |
18166 | @item show prompt | |
18167 | Prints a line of the form: @samp{Gdb's prompt is: @var{your-prompt}} | |
104c1213 JM |
18168 | @end table |
18169 | ||
8e04817f | 18170 | @node Editing |
79a6e687 | 18171 | @section Command Editing |
8e04817f AC |
18172 | @cindex readline |
18173 | @cindex command line editing | |
104c1213 | 18174 | |
703663ab | 18175 | @value{GDBN} reads its input commands via the @dfn{Readline} interface. This |
8e04817f AC |
18176 | @sc{gnu} library provides consistent behavior for programs which provide a |
18177 | command line interface to the user. Advantages are @sc{gnu} Emacs-style | |
18178 | or @dfn{vi}-style inline editing of commands, @code{csh}-like history | |
18179 | substitution, and a storage and recall of command history across | |
18180 | debugging sessions. | |
104c1213 | 18181 | |
8e04817f AC |
18182 | You may control the behavior of command line editing in @value{GDBN} with the |
18183 | command @code{set}. | |
104c1213 | 18184 | |
8e04817f AC |
18185 | @table @code |
18186 | @kindex set editing | |
18187 | @cindex editing | |
18188 | @item set editing | |
18189 | @itemx set editing on | |
18190 | Enable command line editing (enabled by default). | |
104c1213 | 18191 | |
8e04817f AC |
18192 | @item set editing off |
18193 | Disable command line editing. | |
104c1213 | 18194 | |
8e04817f AC |
18195 | @kindex show editing |
18196 | @item show editing | |
18197 | Show whether command line editing is enabled. | |
104c1213 JM |
18198 | @end table |
18199 | ||
703663ab EZ |
18200 | @xref{Command Line Editing}, for more details about the Readline |
18201 | interface. Users unfamiliar with @sc{gnu} Emacs or @code{vi} are | |
18202 | encouraged to read that chapter. | |
18203 | ||
d620b259 | 18204 | @node Command History |
79a6e687 | 18205 | @section Command History |
703663ab | 18206 | @cindex command history |
8e04817f AC |
18207 | |
18208 | @value{GDBN} can keep track of the commands you type during your | |
18209 | debugging sessions, so that you can be certain of precisely what | |
18210 | happened. Use these commands to manage the @value{GDBN} command | |
18211 | history facility. | |
104c1213 | 18212 | |
703663ab EZ |
18213 | @value{GDBN} uses the @sc{gnu} History library, a part of the Readline |
18214 | package, to provide the history facility. @xref{Using History | |
18215 | Interactively}, for the detailed description of the History library. | |
18216 | ||
d620b259 | 18217 | To issue a command to @value{GDBN} without affecting certain aspects of |
9e6c4bd5 NR |
18218 | the state which is seen by users, prefix it with @samp{server } |
18219 | (@pxref{Server Prefix}). This | |
d620b259 NR |
18220 | means that this command will not affect the command history, nor will it |
18221 | affect @value{GDBN}'s notion of which command to repeat if @key{RET} is | |
18222 | pressed on a line by itself. | |
18223 | ||
18224 | @cindex @code{server}, command prefix | |
18225 | The server prefix does not affect the recording of values into the value | |
18226 | history; to print a value without recording it into the value history, | |
18227 | use the @code{output} command instead of the @code{print} command. | |
18228 | ||
703663ab EZ |
18229 | Here is the description of @value{GDBN} commands related to command |
18230 | history. | |
18231 | ||
104c1213 | 18232 | @table @code |
8e04817f AC |
18233 | @cindex history substitution |
18234 | @cindex history file | |
18235 | @kindex set history filename | |
4644b6e3 | 18236 | @cindex @env{GDBHISTFILE}, environment variable |
8e04817f AC |
18237 | @item set history filename @var{fname} |
18238 | Set the name of the @value{GDBN} command history file to @var{fname}. | |
18239 | This is the file where @value{GDBN} reads an initial command history | |
18240 | list, and where it writes the command history from this session when it | |
18241 | exits. You can access this list through history expansion or through | |
18242 | the history command editing characters listed below. This file defaults | |
18243 | to the value of the environment variable @code{GDBHISTFILE}, or to | |
18244 | @file{./.gdb_history} (@file{./_gdb_history} on MS-DOS) if this variable | |
18245 | is not set. | |
104c1213 | 18246 | |
9c16f35a EZ |
18247 | @cindex save command history |
18248 | @kindex set history save | |
8e04817f AC |
18249 | @item set history save |
18250 | @itemx set history save on | |
18251 | Record command history in a file, whose name may be specified with the | |
18252 | @code{set history filename} command. By default, this option is disabled. | |
104c1213 | 18253 | |
8e04817f AC |
18254 | @item set history save off |
18255 | Stop recording command history in a file. | |
104c1213 | 18256 | |
8e04817f | 18257 | @cindex history size |
9c16f35a | 18258 | @kindex set history size |
6fc08d32 | 18259 | @cindex @env{HISTSIZE}, environment variable |
8e04817f AC |
18260 | @item set history size @var{size} |
18261 | Set the number of commands which @value{GDBN} keeps in its history list. | |
18262 | This defaults to the value of the environment variable | |
18263 | @code{HISTSIZE}, or to 256 if this variable is not set. | |
104c1213 JM |
18264 | @end table |
18265 | ||
8e04817f | 18266 | History expansion assigns special meaning to the character @kbd{!}. |
703663ab | 18267 | @xref{Event Designators}, for more details. |
8e04817f | 18268 | |
703663ab | 18269 | @cindex history expansion, turn on/off |
8e04817f AC |
18270 | Since @kbd{!} is also the logical not operator in C, history expansion |
18271 | is off by default. If you decide to enable history expansion with the | |
18272 | @code{set history expansion on} command, you may sometimes need to | |
18273 | follow @kbd{!} (when it is used as logical not, in an expression) with | |
18274 | a space or a tab to prevent it from being expanded. The readline | |
18275 | history facilities do not attempt substitution on the strings | |
18276 | @kbd{!=} and @kbd{!(}, even when history expansion is enabled. | |
18277 | ||
18278 | The commands to control history expansion are: | |
104c1213 JM |
18279 | |
18280 | @table @code | |
8e04817f AC |
18281 | @item set history expansion on |
18282 | @itemx set history expansion | |
703663ab | 18283 | @kindex set history expansion |
8e04817f | 18284 | Enable history expansion. History expansion is off by default. |
104c1213 | 18285 | |
8e04817f AC |
18286 | @item set history expansion off |
18287 | Disable history expansion. | |
104c1213 | 18288 | |
8e04817f AC |
18289 | @c @group |
18290 | @kindex show history | |
18291 | @item show history | |
18292 | @itemx show history filename | |
18293 | @itemx show history save | |
18294 | @itemx show history size | |
18295 | @itemx show history expansion | |
18296 | These commands display the state of the @value{GDBN} history parameters. | |
18297 | @code{show history} by itself displays all four states. | |
18298 | @c @end group | |
18299 | @end table | |
18300 | ||
18301 | @table @code | |
9c16f35a EZ |
18302 | @kindex show commands |
18303 | @cindex show last commands | |
18304 | @cindex display command history | |
8e04817f AC |
18305 | @item show commands |
18306 | Display the last ten commands in the command history. | |
104c1213 | 18307 | |
8e04817f AC |
18308 | @item show commands @var{n} |
18309 | Print ten commands centered on command number @var{n}. | |
18310 | ||
18311 | @item show commands + | |
18312 | Print ten commands just after the commands last printed. | |
104c1213 JM |
18313 | @end table |
18314 | ||
8e04817f | 18315 | @node Screen Size |
79a6e687 | 18316 | @section Screen Size |
8e04817f AC |
18317 | @cindex size of screen |
18318 | @cindex pauses in output | |
104c1213 | 18319 | |
8e04817f AC |
18320 | Certain commands to @value{GDBN} may produce large amounts of |
18321 | information output to the screen. To help you read all of it, | |
18322 | @value{GDBN} pauses and asks you for input at the end of each page of | |
18323 | output. Type @key{RET} when you want to continue the output, or @kbd{q} | |
18324 | to discard the remaining output. Also, the screen width setting | |
18325 | determines when to wrap lines of output. Depending on what is being | |
18326 | printed, @value{GDBN} tries to break the line at a readable place, | |
18327 | rather than simply letting it overflow onto the following line. | |
18328 | ||
18329 | Normally @value{GDBN} knows the size of the screen from the terminal | |
18330 | driver software. For example, on Unix @value{GDBN} uses the termcap data base | |
18331 | together with the value of the @code{TERM} environment variable and the | |
18332 | @code{stty rows} and @code{stty cols} settings. If this is not correct, | |
18333 | you can override it with the @code{set height} and @code{set | |
18334 | width} commands: | |
18335 | ||
18336 | @table @code | |
18337 | @kindex set height | |
18338 | @kindex set width | |
18339 | @kindex show width | |
18340 | @kindex show height | |
18341 | @item set height @var{lpp} | |
18342 | @itemx show height | |
18343 | @itemx set width @var{cpl} | |
18344 | @itemx show width | |
18345 | These @code{set} commands specify a screen height of @var{lpp} lines and | |
18346 | a screen width of @var{cpl} characters. The associated @code{show} | |
18347 | commands display the current settings. | |
104c1213 | 18348 | |
8e04817f AC |
18349 | If you specify a height of zero lines, @value{GDBN} does not pause during |
18350 | output no matter how long the output is. This is useful if output is to a | |
18351 | file or to an editor buffer. | |
104c1213 | 18352 | |
8e04817f AC |
18353 | Likewise, you can specify @samp{set width 0} to prevent @value{GDBN} |
18354 | from wrapping its output. | |
9c16f35a EZ |
18355 | |
18356 | @item set pagination on | |
18357 | @itemx set pagination off | |
18358 | @kindex set pagination | |
18359 | Turn the output pagination on or off; the default is on. Turning | |
18360 | pagination off is the alternative to @code{set height 0}. | |
18361 | ||
18362 | @item show pagination | |
18363 | @kindex show pagination | |
18364 | Show the current pagination mode. | |
104c1213 JM |
18365 | @end table |
18366 | ||
8e04817f AC |
18367 | @node Numbers |
18368 | @section Numbers | |
18369 | @cindex number representation | |
18370 | @cindex entering numbers | |
104c1213 | 18371 | |
8e04817f AC |
18372 | You can always enter numbers in octal, decimal, or hexadecimal in |
18373 | @value{GDBN} by the usual conventions: octal numbers begin with | |
18374 | @samp{0}, decimal numbers end with @samp{.}, and hexadecimal numbers | |
eb2dae08 EZ |
18375 | begin with @samp{0x}. Numbers that neither begin with @samp{0} or |
18376 | @samp{0x}, nor end with a @samp{.} are, by default, entered in base | |
18377 | 10; likewise, the default display for numbers---when no particular | |
18378 | format is specified---is base 10. You can change the default base for | |
18379 | both input and output with the commands described below. | |
104c1213 | 18380 | |
8e04817f AC |
18381 | @table @code |
18382 | @kindex set input-radix | |
18383 | @item set input-radix @var{base} | |
18384 | Set the default base for numeric input. Supported choices | |
18385 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
eb2dae08 | 18386 | specified either unambiguously or using the current input radix; for |
8e04817f | 18387 | example, any of |
104c1213 | 18388 | |
8e04817f | 18389 | @smallexample |
9c16f35a EZ |
18390 | set input-radix 012 |
18391 | set input-radix 10. | |
18392 | set input-radix 0xa | |
8e04817f | 18393 | @end smallexample |
104c1213 | 18394 | |
8e04817f | 18395 | @noindent |
9c16f35a | 18396 | sets the input base to decimal. On the other hand, @samp{set input-radix 10} |
eb2dae08 EZ |
18397 | leaves the input radix unchanged, no matter what it was, since |
18398 | @samp{10}, being without any leading or trailing signs of its base, is | |
18399 | interpreted in the current radix. Thus, if the current radix is 16, | |
18400 | @samp{10} is interpreted in hex, i.e.@: as 16 decimal, which doesn't | |
18401 | change the radix. | |
104c1213 | 18402 | |
8e04817f AC |
18403 | @kindex set output-radix |
18404 | @item set output-radix @var{base} | |
18405 | Set the default base for numeric display. Supported choices | |
18406 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
eb2dae08 | 18407 | specified either unambiguously or using the current input radix. |
104c1213 | 18408 | |
8e04817f AC |
18409 | @kindex show input-radix |
18410 | @item show input-radix | |
18411 | Display the current default base for numeric input. | |
104c1213 | 18412 | |
8e04817f AC |
18413 | @kindex show output-radix |
18414 | @item show output-radix | |
18415 | Display the current default base for numeric display. | |
9c16f35a EZ |
18416 | |
18417 | @item set radix @r{[}@var{base}@r{]} | |
18418 | @itemx show radix | |
18419 | @kindex set radix | |
18420 | @kindex show radix | |
18421 | These commands set and show the default base for both input and output | |
18422 | of numbers. @code{set radix} sets the radix of input and output to | |
18423 | the same base; without an argument, it resets the radix back to its | |
18424 | default value of 10. | |
18425 | ||
8e04817f | 18426 | @end table |
104c1213 | 18427 | |
1e698235 | 18428 | @node ABI |
79a6e687 | 18429 | @section Configuring the Current ABI |
1e698235 DJ |
18430 | |
18431 | @value{GDBN} can determine the @dfn{ABI} (Application Binary Interface) of your | |
18432 | application automatically. However, sometimes you need to override its | |
18433 | conclusions. Use these commands to manage @value{GDBN}'s view of the | |
18434 | current ABI. | |
18435 | ||
98b45e30 DJ |
18436 | @cindex OS ABI |
18437 | @kindex set osabi | |
b4e9345d | 18438 | @kindex show osabi |
98b45e30 DJ |
18439 | |
18440 | One @value{GDBN} configuration can debug binaries for multiple operating | |
b383017d | 18441 | system targets, either via remote debugging or native emulation. |
98b45e30 DJ |
18442 | @value{GDBN} will autodetect the @dfn{OS ABI} (Operating System ABI) in use, |
18443 | but you can override its conclusion using the @code{set osabi} command. | |
18444 | One example where this is useful is in debugging of binaries which use | |
18445 | an alternate C library (e.g.@: @sc{uClibc} for @sc{gnu}/Linux) which does | |
18446 | not have the same identifying marks that the standard C library for your | |
18447 | platform provides. | |
18448 | ||
18449 | @table @code | |
18450 | @item show osabi | |
18451 | Show the OS ABI currently in use. | |
18452 | ||
18453 | @item set osabi | |
18454 | With no argument, show the list of registered available OS ABI's. | |
18455 | ||
18456 | @item set osabi @var{abi} | |
18457 | Set the current OS ABI to @var{abi}. | |
18458 | @end table | |
18459 | ||
1e698235 | 18460 | @cindex float promotion |
1e698235 DJ |
18461 | |
18462 | Generally, the way that an argument of type @code{float} is passed to a | |
18463 | function depends on whether the function is prototyped. For a prototyped | |
18464 | (i.e.@: ANSI/ISO style) function, @code{float} arguments are passed unchanged, | |
18465 | according to the architecture's convention for @code{float}. For unprototyped | |
18466 | (i.e.@: K&R style) functions, @code{float} arguments are first promoted to type | |
18467 | @code{double} and then passed. | |
18468 | ||
18469 | Unfortunately, some forms of debug information do not reliably indicate whether | |
18470 | a function is prototyped. If @value{GDBN} calls a function that is not marked | |
18471 | as prototyped, it consults @kbd{set coerce-float-to-double}. | |
18472 | ||
18473 | @table @code | |
a8f24a35 | 18474 | @kindex set coerce-float-to-double |
1e698235 DJ |
18475 | @item set coerce-float-to-double |
18476 | @itemx set coerce-float-to-double on | |
18477 | Arguments of type @code{float} will be promoted to @code{double} when passed | |
18478 | to an unprototyped function. This is the default setting. | |
18479 | ||
18480 | @item set coerce-float-to-double off | |
18481 | Arguments of type @code{float} will be passed directly to unprototyped | |
18482 | functions. | |
9c16f35a EZ |
18483 | |
18484 | @kindex show coerce-float-to-double | |
18485 | @item show coerce-float-to-double | |
18486 | Show the current setting of promoting @code{float} to @code{double}. | |
1e698235 DJ |
18487 | @end table |
18488 | ||
f1212245 DJ |
18489 | @kindex set cp-abi |
18490 | @kindex show cp-abi | |
18491 | @value{GDBN} needs to know the ABI used for your program's C@t{++} | |
18492 | objects. The correct C@t{++} ABI depends on which C@t{++} compiler was | |
18493 | used to build your application. @value{GDBN} only fully supports | |
18494 | programs with a single C@t{++} ABI; if your program contains code using | |
18495 | multiple C@t{++} ABI's or if @value{GDBN} can not identify your | |
18496 | program's ABI correctly, you can tell @value{GDBN} which ABI to use. | |
18497 | Currently supported ABI's include ``gnu-v2'', for @code{g++} versions | |
18498 | before 3.0, ``gnu-v3'', for @code{g++} versions 3.0 and later, and | |
18499 | ``hpaCC'' for the HP ANSI C@t{++} compiler. Other C@t{++} compilers may | |
18500 | use the ``gnu-v2'' or ``gnu-v3'' ABI's as well. The default setting is | |
18501 | ``auto''. | |
18502 | ||
18503 | @table @code | |
18504 | @item show cp-abi | |
18505 | Show the C@t{++} ABI currently in use. | |
18506 | ||
18507 | @item set cp-abi | |
18508 | With no argument, show the list of supported C@t{++} ABI's. | |
18509 | ||
18510 | @item set cp-abi @var{abi} | |
18511 | @itemx set cp-abi auto | |
18512 | Set the current C@t{++} ABI to @var{abi}, or return to automatic detection. | |
18513 | @end table | |
18514 | ||
8e04817f | 18515 | @node Messages/Warnings |
79a6e687 | 18516 | @section Optional Warnings and Messages |
104c1213 | 18517 | |
9c16f35a EZ |
18518 | @cindex verbose operation |
18519 | @cindex optional warnings | |
8e04817f AC |
18520 | By default, @value{GDBN} is silent about its inner workings. If you are |
18521 | running on a slow machine, you may want to use the @code{set verbose} | |
18522 | command. This makes @value{GDBN} tell you when it does a lengthy | |
18523 | internal operation, so you will not think it has crashed. | |
104c1213 | 18524 | |
8e04817f AC |
18525 | Currently, the messages controlled by @code{set verbose} are those |
18526 | which announce that the symbol table for a source file is being read; | |
79a6e687 | 18527 | see @code{symbol-file} in @ref{Files, ,Commands to Specify Files}. |
104c1213 | 18528 | |
8e04817f AC |
18529 | @table @code |
18530 | @kindex set verbose | |
18531 | @item set verbose on | |
18532 | Enables @value{GDBN} output of certain informational messages. | |
104c1213 | 18533 | |
8e04817f AC |
18534 | @item set verbose off |
18535 | Disables @value{GDBN} output of certain informational messages. | |
104c1213 | 18536 | |
8e04817f AC |
18537 | @kindex show verbose |
18538 | @item show verbose | |
18539 | Displays whether @code{set verbose} is on or off. | |
18540 | @end table | |
104c1213 | 18541 | |
8e04817f AC |
18542 | By default, if @value{GDBN} encounters bugs in the symbol table of an |
18543 | object file, it is silent; but if you are debugging a compiler, you may | |
79a6e687 BW |
18544 | find this information useful (@pxref{Symbol Errors, ,Errors Reading |
18545 | Symbol Files}). | |
104c1213 | 18546 | |
8e04817f | 18547 | @table @code |
104c1213 | 18548 | |
8e04817f AC |
18549 | @kindex set complaints |
18550 | @item set complaints @var{limit} | |
18551 | Permits @value{GDBN} to output @var{limit} complaints about each type of | |
18552 | unusual symbols before becoming silent about the problem. Set | |
18553 | @var{limit} to zero to suppress all complaints; set it to a large number | |
18554 | to prevent complaints from being suppressed. | |
104c1213 | 18555 | |
8e04817f AC |
18556 | @kindex show complaints |
18557 | @item show complaints | |
18558 | Displays how many symbol complaints @value{GDBN} is permitted to produce. | |
104c1213 | 18559 | |
8e04817f | 18560 | @end table |
104c1213 | 18561 | |
d837706a | 18562 | @anchor{confirmation requests} |
8e04817f AC |
18563 | By default, @value{GDBN} is cautious, and asks what sometimes seems to be a |
18564 | lot of stupid questions to confirm certain commands. For example, if | |
18565 | you try to run a program which is already running: | |
104c1213 | 18566 | |
474c8240 | 18567 | @smallexample |
8e04817f AC |
18568 | (@value{GDBP}) run |
18569 | The program being debugged has been started already. | |
18570 | Start it from the beginning? (y or n) | |
474c8240 | 18571 | @end smallexample |
104c1213 | 18572 | |
8e04817f AC |
18573 | If you are willing to unflinchingly face the consequences of your own |
18574 | commands, you can disable this ``feature'': | |
104c1213 | 18575 | |
8e04817f | 18576 | @table @code |
104c1213 | 18577 | |
8e04817f AC |
18578 | @kindex set confirm |
18579 | @cindex flinching | |
18580 | @cindex confirmation | |
18581 | @cindex stupid questions | |
18582 | @item set confirm off | |
18583 | Disables confirmation requests. | |
104c1213 | 18584 | |
8e04817f AC |
18585 | @item set confirm on |
18586 | Enables confirmation requests (the default). | |
104c1213 | 18587 | |
8e04817f AC |
18588 | @kindex show confirm |
18589 | @item show confirm | |
18590 | Displays state of confirmation requests. | |
18591 | ||
18592 | @end table | |
104c1213 | 18593 | |
16026cd7 AS |
18594 | @cindex command tracing |
18595 | If you need to debug user-defined commands or sourced files you may find it | |
18596 | useful to enable @dfn{command tracing}. In this mode each command will be | |
18597 | printed as it is executed, prefixed with one or more @samp{+} symbols, the | |
18598 | quantity denoting the call depth of each command. | |
18599 | ||
18600 | @table @code | |
18601 | @kindex set trace-commands | |
18602 | @cindex command scripts, debugging | |
18603 | @item set trace-commands on | |
18604 | Enable command tracing. | |
18605 | @item set trace-commands off | |
18606 | Disable command tracing. | |
18607 | @item show trace-commands | |
18608 | Display the current state of command tracing. | |
18609 | @end table | |
18610 | ||
8e04817f | 18611 | @node Debugging Output |
79a6e687 | 18612 | @section Optional Messages about Internal Happenings |
4644b6e3 EZ |
18613 | @cindex optional debugging messages |
18614 | ||
da316a69 EZ |
18615 | @value{GDBN} has commands that enable optional debugging messages from |
18616 | various @value{GDBN} subsystems; normally these commands are of | |
18617 | interest to @value{GDBN} maintainers, or when reporting a bug. This | |
18618 | section documents those commands. | |
18619 | ||
104c1213 | 18620 | @table @code |
a8f24a35 EZ |
18621 | @kindex set exec-done-display |
18622 | @item set exec-done-display | |
18623 | Turns on or off the notification of asynchronous commands' | |
18624 | completion. When on, @value{GDBN} will print a message when an | |
18625 | asynchronous command finishes its execution. The default is off. | |
18626 | @kindex show exec-done-display | |
18627 | @item show exec-done-display | |
18628 | Displays the current setting of asynchronous command completion | |
18629 | notification. | |
4644b6e3 EZ |
18630 | @kindex set debug |
18631 | @cindex gdbarch debugging info | |
a8f24a35 | 18632 | @cindex architecture debugging info |
8e04817f | 18633 | @item set debug arch |
a8f24a35 | 18634 | Turns on or off display of gdbarch debugging info. The default is off |
4644b6e3 | 18635 | @kindex show debug |
8e04817f AC |
18636 | @item show debug arch |
18637 | Displays the current state of displaying gdbarch debugging info. | |
721c2651 EZ |
18638 | @item set debug aix-thread |
18639 | @cindex AIX threads | |
18640 | Display debugging messages about inner workings of the AIX thread | |
18641 | module. | |
18642 | @item show debug aix-thread | |
18643 | Show the current state of AIX thread debugging info display. | |
d97bc12b DE |
18644 | @item set debug dwarf2-die |
18645 | @cindex DWARF2 DIEs | |
18646 | Dump DWARF2 DIEs after they are read in. | |
18647 | The value is the number of nesting levels to print. | |
18648 | A value of zero turns off the display. | |
18649 | @item show debug dwarf2-die | |
18650 | Show the current state of DWARF2 DIE debugging. | |
237fc4c9 PA |
18651 | @item set debug displaced |
18652 | @cindex displaced stepping debugging info | |
18653 | Turns on or off display of @value{GDBN} debugging info for the | |
18654 | displaced stepping support. The default is off. | |
18655 | @item show debug displaced | |
18656 | Displays the current state of displaying @value{GDBN} debugging info | |
18657 | related to displaced stepping. | |
8e04817f | 18658 | @item set debug event |
4644b6e3 | 18659 | @cindex event debugging info |
a8f24a35 | 18660 | Turns on or off display of @value{GDBN} event debugging info. The |
8e04817f | 18661 | default is off. |
8e04817f AC |
18662 | @item show debug event |
18663 | Displays the current state of displaying @value{GDBN} event debugging | |
18664 | info. | |
8e04817f | 18665 | @item set debug expression |
4644b6e3 | 18666 | @cindex expression debugging info |
721c2651 EZ |
18667 | Turns on or off display of debugging info about @value{GDBN} |
18668 | expression parsing. The default is off. | |
8e04817f | 18669 | @item show debug expression |
721c2651 EZ |
18670 | Displays the current state of displaying debugging info about |
18671 | @value{GDBN} expression parsing. | |
7453dc06 | 18672 | @item set debug frame |
4644b6e3 | 18673 | @cindex frame debugging info |
7453dc06 AC |
18674 | Turns on or off display of @value{GDBN} frame debugging info. The |
18675 | default is off. | |
7453dc06 AC |
18676 | @item show debug frame |
18677 | Displays the current state of displaying @value{GDBN} frame debugging | |
18678 | info. | |
cbe54154 PA |
18679 | @item set debug gnu-nat |
18680 | @cindex @sc{gnu}/Hurd debug messages | |
18681 | Turns on or off debugging messages from the @sc{gnu}/Hurd debug support. | |
18682 | @item show debug gnu-nat | |
18683 | Show the current state of @sc{gnu}/Hurd debugging messages. | |
30e91e0b RC |
18684 | @item set debug infrun |
18685 | @cindex inferior debugging info | |
18686 | Turns on or off display of @value{GDBN} debugging info for running the inferior. | |
18687 | The default is off. @file{infrun.c} contains GDB's runtime state machine used | |
18688 | for implementing operations such as single-stepping the inferior. | |
18689 | @item show debug infrun | |
18690 | Displays the current state of @value{GDBN} inferior debugging. | |
da316a69 EZ |
18691 | @item set debug lin-lwp |
18692 | @cindex @sc{gnu}/Linux LWP debug messages | |
18693 | @cindex Linux lightweight processes | |
721c2651 | 18694 | Turns on or off debugging messages from the Linux LWP debug support. |
da316a69 EZ |
18695 | @item show debug lin-lwp |
18696 | Show the current state of Linux LWP debugging messages. | |
b84876c2 PA |
18697 | @item set debug lin-lwp-async |
18698 | @cindex @sc{gnu}/Linux LWP async debug messages | |
18699 | @cindex Linux lightweight processes | |
18700 | Turns on or off debugging messages from the Linux LWP async debug support. | |
18701 | @item show debug lin-lwp-async | |
18702 | Show the current state of Linux LWP async debugging messages. | |
2b4855ab | 18703 | @item set debug observer |
4644b6e3 | 18704 | @cindex observer debugging info |
2b4855ab AC |
18705 | Turns on or off display of @value{GDBN} observer debugging. This |
18706 | includes info such as the notification of observable events. | |
2b4855ab AC |
18707 | @item show debug observer |
18708 | Displays the current state of observer debugging. | |
8e04817f | 18709 | @item set debug overload |
4644b6e3 | 18710 | @cindex C@t{++} overload debugging info |
8e04817f | 18711 | Turns on or off display of @value{GDBN} C@t{++} overload debugging |
359df76b | 18712 | info. This includes info such as ranking of functions, etc. The default |
8e04817f | 18713 | is off. |
8e04817f AC |
18714 | @item show debug overload |
18715 | Displays the current state of displaying @value{GDBN} C@t{++} overload | |
18716 | debugging info. | |
8e04817f AC |
18717 | @cindex packets, reporting on stdout |
18718 | @cindex serial connections, debugging | |
605a56cb DJ |
18719 | @cindex debug remote protocol |
18720 | @cindex remote protocol debugging | |
18721 | @cindex display remote packets | |
8e04817f AC |
18722 | @item set debug remote |
18723 | Turns on or off display of reports on all packets sent back and forth across | |
18724 | the serial line to the remote machine. The info is printed on the | |
18725 | @value{GDBN} standard output stream. The default is off. | |
8e04817f AC |
18726 | @item show debug remote |
18727 | Displays the state of display of remote packets. | |
8e04817f AC |
18728 | @item set debug serial |
18729 | Turns on or off display of @value{GDBN} serial debugging info. The | |
18730 | default is off. | |
8e04817f AC |
18731 | @item show debug serial |
18732 | Displays the current state of displaying @value{GDBN} serial debugging | |
18733 | info. | |
c45da7e6 EZ |
18734 | @item set debug solib-frv |
18735 | @cindex FR-V shared-library debugging | |
18736 | Turns on or off debugging messages for FR-V shared-library code. | |
18737 | @item show debug solib-frv | |
18738 | Display the current state of FR-V shared-library code debugging | |
18739 | messages. | |
8e04817f | 18740 | @item set debug target |
4644b6e3 | 18741 | @cindex target debugging info |
8e04817f AC |
18742 | Turns on or off display of @value{GDBN} target debugging info. This info |
18743 | includes what is going on at the target level of GDB, as it happens. The | |
701b08bb DJ |
18744 | default is 0. Set it to 1 to track events, and to 2 to also track the |
18745 | value of large memory transfers. Changes to this flag do not take effect | |
18746 | until the next time you connect to a target or use the @code{run} command. | |
8e04817f AC |
18747 | @item show debug target |
18748 | Displays the current state of displaying @value{GDBN} target debugging | |
18749 | info. | |
75feb17d DJ |
18750 | @item set debug timestamp |
18751 | @cindex timestampping debugging info | |
18752 | Turns on or off display of timestamps with @value{GDBN} debugging info. | |
18753 | When enabled, seconds and microseconds are displayed before each debugging | |
18754 | message. | |
18755 | @item show debug timestamp | |
18756 | Displays the current state of displaying timestamps with @value{GDBN} | |
18757 | debugging info. | |
c45da7e6 | 18758 | @item set debugvarobj |
4644b6e3 | 18759 | @cindex variable object debugging info |
8e04817f AC |
18760 | Turns on or off display of @value{GDBN} variable object debugging |
18761 | info. The default is off. | |
c45da7e6 | 18762 | @item show debugvarobj |
8e04817f AC |
18763 | Displays the current state of displaying @value{GDBN} variable object |
18764 | debugging info. | |
e776119f DJ |
18765 | @item set debug xml |
18766 | @cindex XML parser debugging | |
18767 | Turns on or off debugging messages for built-in XML parsers. | |
18768 | @item show debug xml | |
18769 | Displays the current state of XML debugging messages. | |
8e04817f | 18770 | @end table |
104c1213 | 18771 | |
14fb1bac JB |
18772 | @node Other Misc Settings |
18773 | @section Other Miscellaneous Settings | |
18774 | @cindex miscellaneous settings | |
18775 | ||
18776 | @table @code | |
18777 | @kindex set interactive-mode | |
18778 | @item set interactive-mode | |
18779 | If @code{on}, forces @value{GDBN} to operate interactively. | |
18780 | If @code{off}, forces @value{GDBN} to operate non-interactively, | |
18781 | If @code{auto} (the default), @value{GDBN} guesses which mode to use, | |
18782 | based on whether the debugger was started in a terminal or not. | |
18783 | ||
18784 | In the vast majority of cases, the debugger should be able to guess | |
18785 | correctly which mode should be used. But this setting can be useful | |
18786 | in certain specific cases, such as running a MinGW @value{GDBN} | |
18787 | inside a cygwin window. | |
18788 | ||
18789 | @kindex show interactive-mode | |
18790 | @item show interactive-mode | |
18791 | Displays whether the debugger is operating in interactive mode or not. | |
18792 | @end table | |
18793 | ||
d57a3c85 TJB |
18794 | @node Extending GDB |
18795 | @chapter Extending @value{GDBN} | |
18796 | @cindex extending GDB | |
18797 | ||
18798 | @value{GDBN} provides two mechanisms for extension. The first is based | |
18799 | on composition of @value{GDBN} commands, and the second is based on the | |
18800 | Python scripting language. | |
18801 | ||
18802 | @menu | |
18803 | * Sequences:: Canned Sequences of Commands | |
18804 | * Python:: Scripting @value{GDBN} using Python | |
18805 | @end menu | |
18806 | ||
8e04817f | 18807 | @node Sequences |
d57a3c85 | 18808 | @section Canned Sequences of Commands |
104c1213 | 18809 | |
8e04817f | 18810 | Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint |
79a6e687 | 18811 | Command Lists}), @value{GDBN} provides two ways to store sequences of |
8e04817f AC |
18812 | commands for execution as a unit: user-defined commands and command |
18813 | files. | |
104c1213 | 18814 | |
8e04817f | 18815 | @menu |
fcc73fe3 EZ |
18816 | * Define:: How to define your own commands |
18817 | * Hooks:: Hooks for user-defined commands | |
18818 | * Command Files:: How to write scripts of commands to be stored in a file | |
18819 | * Output:: Commands for controlled output | |
8e04817f | 18820 | @end menu |
104c1213 | 18821 | |
8e04817f | 18822 | @node Define |
d57a3c85 | 18823 | @subsection User-defined Commands |
104c1213 | 18824 | |
8e04817f | 18825 | @cindex user-defined command |
fcc73fe3 | 18826 | @cindex arguments, to user-defined commands |
8e04817f AC |
18827 | A @dfn{user-defined command} is a sequence of @value{GDBN} commands to |
18828 | which you assign a new name as a command. This is done with the | |
18829 | @code{define} command. User commands may accept up to 10 arguments | |
18830 | separated by whitespace. Arguments are accessed within the user command | |
c03c782f | 18831 | via @code{$arg0@dots{}$arg9}. A trivial example: |
104c1213 | 18832 | |
8e04817f AC |
18833 | @smallexample |
18834 | define adder | |
18835 | print $arg0 + $arg1 + $arg2 | |
c03c782f | 18836 | end |
8e04817f | 18837 | @end smallexample |
104c1213 JM |
18838 | |
18839 | @noindent | |
8e04817f | 18840 | To execute the command use: |
104c1213 | 18841 | |
8e04817f AC |
18842 | @smallexample |
18843 | adder 1 2 3 | |
18844 | @end smallexample | |
104c1213 | 18845 | |
8e04817f AC |
18846 | @noindent |
18847 | This defines the command @code{adder}, which prints the sum of | |
18848 | its three arguments. Note the arguments are text substitutions, so they may | |
18849 | reference variables, use complex expressions, or even perform inferior | |
18850 | functions calls. | |
104c1213 | 18851 | |
fcc73fe3 EZ |
18852 | @cindex argument count in user-defined commands |
18853 | @cindex how many arguments (user-defined commands) | |
c03c782f AS |
18854 | In addition, @code{$argc} may be used to find out how many arguments have |
18855 | been passed. This expands to a number in the range 0@dots{}10. | |
18856 | ||
18857 | @smallexample | |
18858 | define adder | |
18859 | if $argc == 2 | |
18860 | print $arg0 + $arg1 | |
18861 | end | |
18862 | if $argc == 3 | |
18863 | print $arg0 + $arg1 + $arg2 | |
18864 | end | |
18865 | end | |
18866 | @end smallexample | |
18867 | ||
104c1213 | 18868 | @table @code |
104c1213 | 18869 | |
8e04817f AC |
18870 | @kindex define |
18871 | @item define @var{commandname} | |
18872 | Define a command named @var{commandname}. If there is already a command | |
18873 | by that name, you are asked to confirm that you want to redefine it. | |
adb483fe DJ |
18874 | @var{commandname} may be a bare command name consisting of letters, |
18875 | numbers, dashes, and underscores. It may also start with any predefined | |
18876 | prefix command. For example, @samp{define target my-target} creates | |
18877 | a user-defined @samp{target my-target} command. | |
104c1213 | 18878 | |
8e04817f AC |
18879 | The definition of the command is made up of other @value{GDBN} command lines, |
18880 | which are given following the @code{define} command. The end of these | |
18881 | commands is marked by a line containing @code{end}. | |
104c1213 | 18882 | |
8e04817f | 18883 | @kindex document |
ca91424e | 18884 | @kindex end@r{ (user-defined commands)} |
8e04817f AC |
18885 | @item document @var{commandname} |
18886 | Document the user-defined command @var{commandname}, so that it can be | |
18887 | accessed by @code{help}. The command @var{commandname} must already be | |
18888 | defined. This command reads lines of documentation just as @code{define} | |
18889 | reads the lines of the command definition, ending with @code{end}. | |
18890 | After the @code{document} command is finished, @code{help} on command | |
18891 | @var{commandname} displays the documentation you have written. | |
104c1213 | 18892 | |
8e04817f AC |
18893 | You may use the @code{document} command again to change the |
18894 | documentation of a command. Redefining the command with @code{define} | |
18895 | does not change the documentation. | |
104c1213 | 18896 | |
c45da7e6 EZ |
18897 | @kindex dont-repeat |
18898 | @cindex don't repeat command | |
18899 | @item dont-repeat | |
18900 | Used inside a user-defined command, this tells @value{GDBN} that this | |
18901 | command should not be repeated when the user hits @key{RET} | |
18902 | (@pxref{Command Syntax, repeat last command}). | |
18903 | ||
8e04817f AC |
18904 | @kindex help user-defined |
18905 | @item help user-defined | |
18906 | List all user-defined commands, with the first line of the documentation | |
18907 | (if any) for each. | |
104c1213 | 18908 | |
8e04817f AC |
18909 | @kindex show user |
18910 | @item show user | |
18911 | @itemx show user @var{commandname} | |
18912 | Display the @value{GDBN} commands used to define @var{commandname} (but | |
18913 | not its documentation). If no @var{commandname} is given, display the | |
18914 | definitions for all user-defined commands. | |
104c1213 | 18915 | |
fcc73fe3 | 18916 | @cindex infinite recursion in user-defined commands |
20f01a46 DH |
18917 | @kindex show max-user-call-depth |
18918 | @kindex set max-user-call-depth | |
18919 | @item show max-user-call-depth | |
5ca0cb28 DH |
18920 | @itemx set max-user-call-depth |
18921 | The value of @code{max-user-call-depth} controls how many recursion | |
3f94c067 | 18922 | levels are allowed in user-defined commands before @value{GDBN} suspects an |
5ca0cb28 | 18923 | infinite recursion and aborts the command. |
104c1213 JM |
18924 | @end table |
18925 | ||
fcc73fe3 EZ |
18926 | In addition to the above commands, user-defined commands frequently |
18927 | use control flow commands, described in @ref{Command Files}. | |
18928 | ||
8e04817f AC |
18929 | When user-defined commands are executed, the |
18930 | commands of the definition are not printed. An error in any command | |
18931 | stops execution of the user-defined command. | |
104c1213 | 18932 | |
8e04817f AC |
18933 | If used interactively, commands that would ask for confirmation proceed |
18934 | without asking when used inside a user-defined command. Many @value{GDBN} | |
18935 | commands that normally print messages to say what they are doing omit the | |
18936 | messages when used in a user-defined command. | |
104c1213 | 18937 | |
8e04817f | 18938 | @node Hooks |
d57a3c85 | 18939 | @subsection User-defined Command Hooks |
8e04817f AC |
18940 | @cindex command hooks |
18941 | @cindex hooks, for commands | |
18942 | @cindex hooks, pre-command | |
104c1213 | 18943 | |
8e04817f | 18944 | @kindex hook |
8e04817f AC |
18945 | You may define @dfn{hooks}, which are a special kind of user-defined |
18946 | command. Whenever you run the command @samp{foo}, if the user-defined | |
18947 | command @samp{hook-foo} exists, it is executed (with no arguments) | |
18948 | before that command. | |
104c1213 | 18949 | |
8e04817f AC |
18950 | @cindex hooks, post-command |
18951 | @kindex hookpost | |
8e04817f AC |
18952 | A hook may also be defined which is run after the command you executed. |
18953 | Whenever you run the command @samp{foo}, if the user-defined command | |
18954 | @samp{hookpost-foo} exists, it is executed (with no arguments) after | |
18955 | that command. Post-execution hooks may exist simultaneously with | |
18956 | pre-execution hooks, for the same command. | |
104c1213 | 18957 | |
8e04817f | 18958 | It is valid for a hook to call the command which it hooks. If this |
9f1c6395 | 18959 | occurs, the hook is not re-executed, thereby avoiding infinite recursion. |
104c1213 | 18960 | |
8e04817f AC |
18961 | @c It would be nice if hookpost could be passed a parameter indicating |
18962 | @c if the command it hooks executed properly or not. FIXME! | |
104c1213 | 18963 | |
8e04817f AC |
18964 | @kindex stop@r{, a pseudo-command} |
18965 | In addition, a pseudo-command, @samp{stop} exists. Defining | |
18966 | (@samp{hook-stop}) makes the associated commands execute every time | |
18967 | execution stops in your program: before breakpoint commands are run, | |
18968 | displays are printed, or the stack frame is printed. | |
104c1213 | 18969 | |
8e04817f AC |
18970 | For example, to ignore @code{SIGALRM} signals while |
18971 | single-stepping, but treat them normally during normal execution, | |
18972 | you could define: | |
104c1213 | 18973 | |
474c8240 | 18974 | @smallexample |
8e04817f AC |
18975 | define hook-stop |
18976 | handle SIGALRM nopass | |
18977 | end | |
104c1213 | 18978 | |
8e04817f AC |
18979 | define hook-run |
18980 | handle SIGALRM pass | |
18981 | end | |
104c1213 | 18982 | |
8e04817f | 18983 | define hook-continue |
d3e8051b | 18984 | handle SIGALRM pass |
8e04817f | 18985 | end |
474c8240 | 18986 | @end smallexample |
104c1213 | 18987 | |
d3e8051b | 18988 | As a further example, to hook at the beginning and end of the @code{echo} |
b383017d | 18989 | command, and to add extra text to the beginning and end of the message, |
8e04817f | 18990 | you could define: |
104c1213 | 18991 | |
474c8240 | 18992 | @smallexample |
8e04817f AC |
18993 | define hook-echo |
18994 | echo <<<--- | |
18995 | end | |
104c1213 | 18996 | |
8e04817f AC |
18997 | define hookpost-echo |
18998 | echo --->>>\n | |
18999 | end | |
104c1213 | 19000 | |
8e04817f AC |
19001 | (@value{GDBP}) echo Hello World |
19002 | <<<---Hello World--->>> | |
19003 | (@value{GDBP}) | |
104c1213 | 19004 | |
474c8240 | 19005 | @end smallexample |
104c1213 | 19006 | |
8e04817f AC |
19007 | You can define a hook for any single-word command in @value{GDBN}, but |
19008 | not for command aliases; you should define a hook for the basic command | |
c1468174 | 19009 | name, e.g.@: @code{backtrace} rather than @code{bt}. |
8e04817f AC |
19010 | @c FIXME! So how does Joe User discover whether a command is an alias |
19011 | @c or not? | |
adb483fe DJ |
19012 | You can hook a multi-word command by adding @code{hook-} or |
19013 | @code{hookpost-} to the last word of the command, e.g.@: | |
19014 | @samp{define target hook-remote} to add a hook to @samp{target remote}. | |
19015 | ||
8e04817f AC |
19016 | If an error occurs during the execution of your hook, execution of |
19017 | @value{GDBN} commands stops and @value{GDBN} issues a prompt | |
19018 | (before the command that you actually typed had a chance to run). | |
104c1213 | 19019 | |
8e04817f AC |
19020 | If you try to define a hook which does not match any known command, you |
19021 | get a warning from the @code{define} command. | |
c906108c | 19022 | |
8e04817f | 19023 | @node Command Files |
d57a3c85 | 19024 | @subsection Command Files |
c906108c | 19025 | |
8e04817f | 19026 | @cindex command files |
fcc73fe3 | 19027 | @cindex scripting commands |
6fc08d32 EZ |
19028 | A command file for @value{GDBN} is a text file made of lines that are |
19029 | @value{GDBN} commands. Comments (lines starting with @kbd{#}) may | |
19030 | also be included. An empty line in a command file does nothing; it | |
19031 | does not mean to repeat the last command, as it would from the | |
19032 | terminal. | |
c906108c | 19033 | |
6fc08d32 EZ |
19034 | You can request the execution of a command file with the @code{source} |
19035 | command: | |
c906108c | 19036 | |
8e04817f AC |
19037 | @table @code |
19038 | @kindex source | |
ca91424e | 19039 | @cindex execute commands from a file |
16026cd7 | 19040 | @item source [@code{-v}] @var{filename} |
8e04817f | 19041 | Execute the command file @var{filename}. |
c906108c SS |
19042 | @end table |
19043 | ||
fcc73fe3 EZ |
19044 | The lines in a command file are generally executed sequentially, |
19045 | unless the order of execution is changed by one of the | |
19046 | @emph{flow-control commands} described below. The commands are not | |
a71ec265 DH |
19047 | printed as they are executed. An error in any command terminates |
19048 | execution of the command file and control is returned to the console. | |
c906108c | 19049 | |
4b505b12 AS |
19050 | @value{GDBN} searches for @var{filename} in the current directory and then |
19051 | on the search path (specified with the @samp{directory} command). | |
19052 | ||
16026cd7 AS |
19053 | If @code{-v}, for verbose mode, is given then @value{GDBN} displays |
19054 | each command as it is executed. The option must be given before | |
19055 | @var{filename}, and is interpreted as part of the filename anywhere else. | |
19056 | ||
8e04817f AC |
19057 | Commands that would ask for confirmation if used interactively proceed |
19058 | without asking when used in a command file. Many @value{GDBN} commands that | |
19059 | normally print messages to say what they are doing omit the messages | |
19060 | when called from command files. | |
c906108c | 19061 | |
8e04817f AC |
19062 | @value{GDBN} also accepts command input from standard input. In this |
19063 | mode, normal output goes to standard output and error output goes to | |
19064 | standard error. Errors in a command file supplied on standard input do | |
6fc08d32 | 19065 | not terminate execution of the command file---execution continues with |
8e04817f | 19066 | the next command. |
c906108c | 19067 | |
474c8240 | 19068 | @smallexample |
8e04817f | 19069 | gdb < cmds > log 2>&1 |
474c8240 | 19070 | @end smallexample |
c906108c | 19071 | |
8e04817f AC |
19072 | (The syntax above will vary depending on the shell used.) This example |
19073 | will execute commands from the file @file{cmds}. All output and errors | |
19074 | would be directed to @file{log}. | |
c906108c | 19075 | |
fcc73fe3 EZ |
19076 | Since commands stored on command files tend to be more general than |
19077 | commands typed interactively, they frequently need to deal with | |
19078 | complicated situations, such as different or unexpected values of | |
19079 | variables and symbols, changes in how the program being debugged is | |
19080 | built, etc. @value{GDBN} provides a set of flow-control commands to | |
19081 | deal with these complexities. Using these commands, you can write | |
19082 | complex scripts that loop over data structures, execute commands | |
19083 | conditionally, etc. | |
19084 | ||
19085 | @table @code | |
19086 | @kindex if | |
19087 | @kindex else | |
19088 | @item if | |
19089 | @itemx else | |
19090 | This command allows to include in your script conditionally executed | |
19091 | commands. The @code{if} command takes a single argument, which is an | |
19092 | expression to evaluate. It is followed by a series of commands that | |
19093 | are executed only if the expression is true (its value is nonzero). | |
19094 | There can then optionally be an @code{else} line, followed by a series | |
19095 | of commands that are only executed if the expression was false. The | |
19096 | end of the list is marked by a line containing @code{end}. | |
19097 | ||
19098 | @kindex while | |
19099 | @item while | |
19100 | This command allows to write loops. Its syntax is similar to | |
19101 | @code{if}: the command takes a single argument, which is an expression | |
19102 | to evaluate, and must be followed by the commands to execute, one per | |
19103 | line, terminated by an @code{end}. These commands are called the | |
19104 | @dfn{body} of the loop. The commands in the body of @code{while} are | |
19105 | executed repeatedly as long as the expression evaluates to true. | |
19106 | ||
19107 | @kindex loop_break | |
19108 | @item loop_break | |
19109 | This command exits the @code{while} loop in whose body it is included. | |
19110 | Execution of the script continues after that @code{while}s @code{end} | |
19111 | line. | |
19112 | ||
19113 | @kindex loop_continue | |
19114 | @item loop_continue | |
19115 | This command skips the execution of the rest of the body of commands | |
19116 | in the @code{while} loop in whose body it is included. Execution | |
19117 | branches to the beginning of the @code{while} loop, where it evaluates | |
19118 | the controlling expression. | |
ca91424e EZ |
19119 | |
19120 | @kindex end@r{ (if/else/while commands)} | |
19121 | @item end | |
19122 | Terminate the block of commands that are the body of @code{if}, | |
19123 | @code{else}, or @code{while} flow-control commands. | |
fcc73fe3 EZ |
19124 | @end table |
19125 | ||
19126 | ||
8e04817f | 19127 | @node Output |
d57a3c85 | 19128 | @subsection Commands for Controlled Output |
c906108c | 19129 | |
8e04817f AC |
19130 | During the execution of a command file or a user-defined command, normal |
19131 | @value{GDBN} output is suppressed; the only output that appears is what is | |
19132 | explicitly printed by the commands in the definition. This section | |
19133 | describes three commands useful for generating exactly the output you | |
19134 | want. | |
c906108c SS |
19135 | |
19136 | @table @code | |
8e04817f AC |
19137 | @kindex echo |
19138 | @item echo @var{text} | |
19139 | @c I do not consider backslash-space a standard C escape sequence | |
19140 | @c because it is not in ANSI. | |
19141 | Print @var{text}. Nonprinting characters can be included in | |
19142 | @var{text} using C escape sequences, such as @samp{\n} to print a | |
19143 | newline. @strong{No newline is printed unless you specify one.} | |
19144 | In addition to the standard C escape sequences, a backslash followed | |
19145 | by a space stands for a space. This is useful for displaying a | |
19146 | string with spaces at the beginning or the end, since leading and | |
19147 | trailing spaces are otherwise trimmed from all arguments. | |
19148 | To print @samp{@w{ }and foo =@w{ }}, use the command | |
19149 | @samp{echo \@w{ }and foo = \@w{ }}. | |
c906108c | 19150 | |
8e04817f AC |
19151 | A backslash at the end of @var{text} can be used, as in C, to continue |
19152 | the command onto subsequent lines. For example, | |
c906108c | 19153 | |
474c8240 | 19154 | @smallexample |
8e04817f AC |
19155 | echo This is some text\n\ |
19156 | which is continued\n\ | |
19157 | onto several lines.\n | |
474c8240 | 19158 | @end smallexample |
c906108c | 19159 | |
8e04817f | 19160 | produces the same output as |
c906108c | 19161 | |
474c8240 | 19162 | @smallexample |
8e04817f AC |
19163 | echo This is some text\n |
19164 | echo which is continued\n | |
19165 | echo onto several lines.\n | |
474c8240 | 19166 | @end smallexample |
c906108c | 19167 | |
8e04817f AC |
19168 | @kindex output |
19169 | @item output @var{expression} | |
19170 | Print the value of @var{expression} and nothing but that value: no | |
19171 | newlines, no @samp{$@var{nn} = }. The value is not entered in the | |
19172 | value history either. @xref{Expressions, ,Expressions}, for more information | |
19173 | on expressions. | |
c906108c | 19174 | |
8e04817f AC |
19175 | @item output/@var{fmt} @var{expression} |
19176 | Print the value of @var{expression} in format @var{fmt}. You can use | |
19177 | the same formats as for @code{print}. @xref{Output Formats,,Output | |
79a6e687 | 19178 | Formats}, for more information. |
c906108c | 19179 | |
8e04817f | 19180 | @kindex printf |
82160952 EZ |
19181 | @item printf @var{template}, @var{expressions}@dots{} |
19182 | Print the values of one or more @var{expressions} under the control of | |
19183 | the string @var{template}. To print several values, make | |
19184 | @var{expressions} be a comma-separated list of individual expressions, | |
19185 | which may be either numbers or pointers. Their values are printed as | |
19186 | specified by @var{template}, exactly as a C program would do by | |
19187 | executing the code below: | |
c906108c | 19188 | |
474c8240 | 19189 | @smallexample |
82160952 | 19190 | printf (@var{template}, @var{expressions}@dots{}); |
474c8240 | 19191 | @end smallexample |
c906108c | 19192 | |
82160952 EZ |
19193 | As in @code{C} @code{printf}, ordinary characters in @var{template} |
19194 | are printed verbatim, while @dfn{conversion specification} introduced | |
19195 | by the @samp{%} character cause subsequent @var{expressions} to be | |
19196 | evaluated, their values converted and formatted according to type and | |
19197 | style information encoded in the conversion specifications, and then | |
19198 | printed. | |
19199 | ||
8e04817f | 19200 | For example, you can print two values in hex like this: |
c906108c | 19201 | |
8e04817f AC |
19202 | @smallexample |
19203 | printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo | |
19204 | @end smallexample | |
c906108c | 19205 | |
82160952 EZ |
19206 | @code{printf} supports all the standard @code{C} conversion |
19207 | specifications, including the flags and modifiers between the @samp{%} | |
19208 | character and the conversion letter, with the following exceptions: | |
19209 | ||
19210 | @itemize @bullet | |
19211 | @item | |
19212 | The argument-ordering modifiers, such as @samp{2$}, are not supported. | |
19213 | ||
19214 | @item | |
19215 | The modifier @samp{*} is not supported for specifying precision or | |
19216 | width. | |
19217 | ||
19218 | @item | |
19219 | The @samp{'} flag (for separation of digits into groups according to | |
19220 | @code{LC_NUMERIC'}) is not supported. | |
19221 | ||
19222 | @item | |
19223 | The type modifiers @samp{hh}, @samp{j}, @samp{t}, and @samp{z} are not | |
19224 | supported. | |
19225 | ||
19226 | @item | |
19227 | The conversion letter @samp{n} (as in @samp{%n}) is not supported. | |
19228 | ||
19229 | @item | |
19230 | The conversion letters @samp{a} and @samp{A} are not supported. | |
19231 | @end itemize | |
19232 | ||
19233 | @noindent | |
19234 | Note that the @samp{ll} type modifier is supported only if the | |
19235 | underlying @code{C} implementation used to build @value{GDBN} supports | |
19236 | the @code{long long int} type, and the @samp{L} type modifier is | |
19237 | supported only if @code{long double} type is available. | |
19238 | ||
19239 | As in @code{C}, @code{printf} supports simple backslash-escape | |
19240 | sequences, such as @code{\n}, @samp{\t}, @samp{\\}, @samp{\"}, | |
19241 | @samp{\a}, and @samp{\f}, that consist of backslash followed by a | |
19242 | single character. Octal and hexadecimal escape sequences are not | |
19243 | supported. | |
1a619819 LM |
19244 | |
19245 | Additionally, @code{printf} supports conversion specifications for DFP | |
0aea4bf3 LM |
19246 | (@dfn{Decimal Floating Point}) types using the following length modifiers |
19247 | together with a floating point specifier. | |
1a619819 LM |
19248 | letters: |
19249 | ||
19250 | @itemize @bullet | |
19251 | @item | |
19252 | @samp{H} for printing @code{Decimal32} types. | |
19253 | ||
19254 | @item | |
19255 | @samp{D} for printing @code{Decimal64} types. | |
19256 | ||
19257 | @item | |
19258 | @samp{DD} for printing @code{Decimal128} types. | |
19259 | @end itemize | |
19260 | ||
19261 | If the underlying @code{C} implementation used to build @value{GDBN} has | |
0aea4bf3 | 19262 | support for the three length modifiers for DFP types, other modifiers |
3b784c4f | 19263 | such as width and precision will also be available for @value{GDBN} to use. |
1a619819 LM |
19264 | |
19265 | In case there is no such @code{C} support, no additional modifiers will be | |
19266 | available and the value will be printed in the standard way. | |
19267 | ||
19268 | Here's an example of printing DFP types using the above conversion letters: | |
19269 | @smallexample | |
0aea4bf3 | 19270 | printf "D32: %Hf - D64: %Df - D128: %DDf\n",1.2345df,1.2E10dd,1.2E1dl |
1a619819 LM |
19271 | @end smallexample |
19272 | ||
c906108c SS |
19273 | @end table |
19274 | ||
d57a3c85 TJB |
19275 | @node Python |
19276 | @section Scripting @value{GDBN} using Python | |
19277 | @cindex python scripting | |
19278 | @cindex scripting with python | |
19279 | ||
19280 | You can script @value{GDBN} using the @uref{http://www.python.org/, | |
19281 | Python programming language}. This feature is available only if | |
19282 | @value{GDBN} was configured using @option{--with-python}. | |
19283 | ||
19284 | @menu | |
19285 | * Python Commands:: Accessing Python from @value{GDBN}. | |
19286 | * Python API:: Accessing @value{GDBN} from Python. | |
19287 | @end menu | |
19288 | ||
19289 | @node Python Commands | |
19290 | @subsection Python Commands | |
19291 | @cindex python commands | |
19292 | @cindex commands to access python | |
19293 | ||
19294 | @value{GDBN} provides one command for accessing the Python interpreter, | |
19295 | and one related setting: | |
19296 | ||
19297 | @table @code | |
19298 | @kindex python | |
19299 | @item python @r{[}@var{code}@r{]} | |
19300 | The @code{python} command can be used to evaluate Python code. | |
19301 | ||
19302 | If given an argument, the @code{python} command will evaluate the | |
19303 | argument as a Python command. For example: | |
19304 | ||
19305 | @smallexample | |
19306 | (@value{GDBP}) python print 23 | |
19307 | 23 | |
19308 | @end smallexample | |
19309 | ||
19310 | If you do not provide an argument to @code{python}, it will act as a | |
19311 | multi-line command, like @code{define}. In this case, the Python | |
19312 | script is made up of subsequent command lines, given after the | |
19313 | @code{python} command. This command list is terminated using a line | |
19314 | containing @code{end}. For example: | |
19315 | ||
19316 | @smallexample | |
19317 | (@value{GDBP}) python | |
19318 | Type python script | |
19319 | End with a line saying just "end". | |
19320 | >print 23 | |
19321 | >end | |
19322 | 23 | |
19323 | @end smallexample | |
19324 | ||
19325 | @kindex maint set python print-stack | |
19326 | @item maint set python print-stack | |
19327 | By default, @value{GDBN} will print a stack trace when an error occurs | |
19328 | in a Python script. This can be controlled using @code{maint set | |
19329 | python print-stack}: if @code{on}, the default, then Python stack | |
19330 | printing is enabled; if @code{off}, then Python stack printing is | |
19331 | disabled. | |
19332 | @end table | |
19333 | ||
19334 | @node Python API | |
19335 | @subsection Python API | |
19336 | @cindex python api | |
19337 | @cindex programming in python | |
19338 | ||
19339 | @cindex python stdout | |
19340 | @cindex python pagination | |
19341 | At startup, @value{GDBN} overrides Python's @code{sys.stdout} and | |
19342 | @code{sys.stderr} to print using @value{GDBN}'s output-paging streams. | |
19343 | A Python program which outputs to one of these streams may have its | |
19344 | output interrupted by the user (@pxref{Screen Size}). In this | |
19345 | situation, a Python @code{KeyboardInterrupt} exception is thrown. | |
19346 | ||
19347 | @menu | |
19348 | * Basic Python:: Basic Python Functions. | |
19349 | * Exception Handling:: | |
89c73ade | 19350 | * Auto-loading:: Automatically loading Python code. |
a08702d6 | 19351 | * Values From Inferior:: |
2c74e833 | 19352 | * Types In Python:: Python representation of types. |
a6bac58e TT |
19353 | * Pretty Printing:: Pretty-printing values. |
19354 | * Selecting Pretty-Printers:: How GDB chooses a pretty-printer. | |
d8906c6f | 19355 | * Commands In Python:: Implementing new commands in Python. |
bc3b79fd | 19356 | * Functions In Python:: Writing new convenience functions. |
89c73ade | 19357 | * Objfiles In Python:: Object files. |
f8f6f20b | 19358 | * Frames In Python:: Acessing inferior stack frames from Python. |
d57a3c85 TJB |
19359 | @end menu |
19360 | ||
19361 | @node Basic Python | |
19362 | @subsubsection Basic Python | |
19363 | ||
19364 | @cindex python functions | |
19365 | @cindex python module | |
19366 | @cindex gdb module | |
19367 | @value{GDBN} introduces a new Python module, named @code{gdb}. All | |
19368 | methods and classes added by @value{GDBN} are placed in this module. | |
19369 | @value{GDBN} automatically @code{import}s the @code{gdb} module for | |
19370 | use in all scripts evaluated by the @code{python} command. | |
19371 | ||
19372 | @findex gdb.execute | |
12453b93 | 19373 | @defun execute command [from_tty] |
d57a3c85 TJB |
19374 | Evaluate @var{command}, a string, as a @value{GDBN} CLI command. |
19375 | If a GDB exception happens while @var{command} runs, it is | |
19376 | translated as described in @ref{Exception Handling,,Exception Handling}. | |
19377 | If no exceptions occur, this function returns @code{None}. | |
12453b93 TJB |
19378 | |
19379 | @var{from_tty} specifies whether @value{GDBN} ought to consider this | |
19380 | command as having originated from the user invoking it interactively. | |
19381 | It must be a boolean value. If omitted, it defaults to @code{False}. | |
d57a3c85 TJB |
19382 | @end defun |
19383 | ||
8f500870 TT |
19384 | @findex gdb.parameter |
19385 | @defun parameter parameter | |
d57a3c85 TJB |
19386 | Return the value of a @value{GDBN} parameter. @var{parameter} is a |
19387 | string naming the parameter to look up; @var{parameter} may contain | |
19388 | spaces if the parameter has a multi-part name. For example, | |
19389 | @samp{print object} is a valid parameter name. | |
19390 | ||
19391 | If the named parameter does not exist, this function throws a | |
19392 | @code{RuntimeError}. Otherwise, the parameter's value is converted to | |
19393 | a Python value of the appropriate type, and returned. | |
19394 | @end defun | |
19395 | ||
08c637de TJB |
19396 | @findex gdb.history |
19397 | @defun history number | |
19398 | Return a value from @value{GDBN}'s value history (@pxref{Value | |
19399 | History}). @var{number} indicates which history element to return. | |
19400 | If @var{number} is negative, then @value{GDBN} will take its absolute value | |
19401 | and count backward from the last element (i.e., the most recent element) to | |
19402 | find the value to return. If @var{number} is zero, then @value{GDBN} will | |
a0c36267 | 19403 | return the most recent element. If the element specified by @var{number} |
08c637de TJB |
19404 | doesn't exist in the value history, a @code{RuntimeError} exception will be |
19405 | raised. | |
19406 | ||
19407 | If no exception is raised, the return value is always an instance of | |
19408 | @code{gdb.Value} (@pxref{Values From Inferior}). | |
19409 | @end defun | |
19410 | ||
57a1d736 TT |
19411 | @findex gdb.parse_and_eval |
19412 | @defun parse_and_eval expression | |
19413 | Parse @var{expression} as an expression in the current language, | |
19414 | evaluate it, and return the result as a @code{gdb.Value}. | |
19415 | @var{expression} must be a string. | |
19416 | ||
19417 | This function can be useful when implementing a new command | |
19418 | (@pxref{Commands In Python}), as it provides a way to parse the | |
19419 | command's argument as an expression. It is also useful simply to | |
19420 | compute values, for example, it is the only way to get the value of a | |
19421 | convenience variable (@pxref{Convenience Vars}) as a @code{gdb.Value}. | |
19422 | @end defun | |
19423 | ||
d57a3c85 TJB |
19424 | @findex gdb.write |
19425 | @defun write string | |
19426 | Print a string to @value{GDBN}'s paginated standard output stream. | |
19427 | Writing to @code{sys.stdout} or @code{sys.stderr} will automatically | |
19428 | call this function. | |
19429 | @end defun | |
19430 | ||
19431 | @findex gdb.flush | |
19432 | @defun flush | |
19433 | Flush @value{GDBN}'s paginated standard output stream. Flushing | |
19434 | @code{sys.stdout} or @code{sys.stderr} will automatically call this | |
19435 | function. | |
19436 | @end defun | |
19437 | ||
19438 | @node Exception Handling | |
19439 | @subsubsection Exception Handling | |
19440 | @cindex python exceptions | |
19441 | @cindex exceptions, python | |
19442 | ||
19443 | When executing the @code{python} command, Python exceptions | |
19444 | uncaught within the Python code are translated to calls to | |
19445 | @value{GDBN} error-reporting mechanism. If the command that called | |
19446 | @code{python} does not handle the error, @value{GDBN} will | |
19447 | terminate it and print an error message containing the Python | |
19448 | exception name, the associated value, and the Python call stack | |
19449 | backtrace at the point where the exception was raised. Example: | |
19450 | ||
19451 | @smallexample | |
19452 | (@value{GDBP}) python print foo | |
19453 | Traceback (most recent call last): | |
19454 | File "<string>", line 1, in <module> | |
19455 | NameError: name 'foo' is not defined | |
19456 | @end smallexample | |
19457 | ||
19458 | @value{GDBN} errors that happen in @value{GDBN} commands invoked by Python | |
19459 | code are converted to Python @code{RuntimeError} exceptions. User | |
19460 | interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination | |
19461 | prompt) is translated to a Python @code{KeyboardInterrupt} | |
19462 | exception. If you catch these exceptions in your Python code, your | |
19463 | exception handler will see @code{RuntimeError} or | |
19464 | @code{KeyboardInterrupt} as the exception type, the @value{GDBN} error | |
19465 | message as its value, and the Python call stack backtrace at the | |
19466 | Python statement closest to where the @value{GDBN} error occured as the | |
19467 | traceback. | |
19468 | ||
89c73ade TT |
19469 | @node Auto-loading |
19470 | @subsubsection Auto-loading | |
19471 | @cindex auto-loading, Python | |
19472 | ||
19473 | When a new object file is read (for example, due to the @code{file} | |
19474 | command, or because the inferior has loaded a shared library), | |
19475 | @value{GDBN} will look for a file named @file{@var{objfile}-gdb.py}, | |
19476 | where @var{objfile} is the object file's real name, formed by ensuring | |
19477 | that the file name is absolute, following all symlinks, and resolving | |
19478 | @code{.} and @code{..} components. If this file exists and is | |
19479 | readable, @value{GDBN} will evaluate it as a Python script. | |
19480 | ||
19481 | If this file does not exist, and if the parameter | |
19482 | @code{debug-file-directory} is set (@pxref{Separate Debug Files}), | |
24ddea62 JK |
19483 | then @value{GDBN} will use for its each separated directory component |
19484 | @code{component} the file named @file{@code{component}/@var{real-name}}, where | |
89c73ade TT |
19485 | @var{real-name} is the object file's real name, as described above. |
19486 | ||
19487 | Finally, if this file does not exist, then @value{GDBN} will look for | |
19488 | a file named @file{@var{data-directory}/python/auto-load/@var{real-name}}, where | |
19489 | @var{data-directory} is @value{GDBN}'s data directory (available via | |
19490 | @code{show data-directory}, @pxref{Data Files}), and @var{real-name} | |
19491 | is the object file's real name, as described above. | |
19492 | ||
19493 | When reading an auto-loaded file, @value{GDBN} sets the ``current | |
19494 | objfile''. This is available via the @code{gdb.current_objfile} | |
19495 | function (@pxref{Objfiles In Python}). This can be useful for | |
19496 | registering objfile-specific pretty-printers. | |
19497 | ||
19498 | The auto-loading feature is useful for supplying application-specific | |
19499 | debugging commands and scripts. You can enable or disable this | |
19500 | feature, and view its current state. | |
19501 | ||
19502 | @table @code | |
19503 | @kindex maint set python auto-load | |
19504 | @item maint set python auto-load [yes|no] | |
19505 | Enable or disable the Python auto-loading feature. | |
19506 | ||
19507 | @kindex show python auto-load | |
19508 | @item show python auto-load | |
19509 | Show whether Python auto-loading is enabled or disabled. | |
19510 | @end table | |
19511 | ||
19512 | @value{GDBN} does not track which files it has already auto-loaded. | |
19513 | So, your @samp{-gdb.py} file should take care to ensure that it may be | |
19514 | evaluated multiple times without error. | |
19515 | ||
a08702d6 TJB |
19516 | @node Values From Inferior |
19517 | @subsubsection Values From Inferior | |
19518 | @cindex values from inferior, with Python | |
19519 | @cindex python, working with values from inferior | |
19520 | ||
19521 | @cindex @code{gdb.Value} | |
19522 | @value{GDBN} provides values it obtains from the inferior program in | |
19523 | an object of type @code{gdb.Value}. @value{GDBN} uses this object | |
19524 | for its internal bookkeeping of the inferior's values, and for | |
19525 | fetching values when necessary. | |
19526 | ||
19527 | Inferior values that are simple scalars can be used directly in | |
19528 | Python expressions that are valid for the value's data type. Here's | |
19529 | an example for an integer or floating-point value @code{some_val}: | |
19530 | ||
19531 | @smallexample | |
19532 | bar = some_val + 2 | |
19533 | @end smallexample | |
19534 | ||
19535 | @noindent | |
19536 | As result of this, @code{bar} will also be a @code{gdb.Value} object | |
19537 | whose values are of the same type as those of @code{some_val}. | |
19538 | ||
19539 | Inferior values that are structures or instances of some class can | |
19540 | be accessed using the Python @dfn{dictionary syntax}. For example, if | |
19541 | @code{some_val} is a @code{gdb.Value} instance holding a structure, you | |
19542 | can access its @code{foo} element with: | |
19543 | ||
19544 | @smallexample | |
19545 | bar = some_val['foo'] | |
19546 | @end smallexample | |
19547 | ||
19548 | Again, @code{bar} will also be a @code{gdb.Value} object. | |
19549 | ||
c0c6f777 | 19550 | The following attributes are provided: |
a08702d6 | 19551 | |
def2b000 | 19552 | @table @code |
2c74e833 | 19553 | @defivar Value address |
c0c6f777 TJB |
19554 | If this object is addressable, this read-only attribute holds a |
19555 | @code{gdb.Value} object representing the address. Otherwise, | |
19556 | this attribute holds @code{None}. | |
2c74e833 | 19557 | @end defivar |
c0c6f777 | 19558 | |
def2b000 | 19559 | @cindex optimized out value in Python |
2c74e833 | 19560 | @defivar Value is_optimized_out |
def2b000 TJB |
19561 | This read-only boolean attribute is true if the compiler optimized out |
19562 | this value, thus it is not available for fetching from the inferior. | |
2c74e833 TT |
19563 | @end defivar |
19564 | ||
19565 | @defivar Value type | |
19566 | The type of this @code{gdb.Value}. The value of this attribute is a | |
19567 | @code{gdb.Type} object. | |
19568 | @end defivar | |
def2b000 TJB |
19569 | @end table |
19570 | ||
19571 | The following methods are provided: | |
19572 | ||
19573 | @table @code | |
14ff2235 PM |
19574 | @defmethod Value cast type |
19575 | Return a new instance of @code{gdb.Value} that is the result of | |
19576 | casting this instance to the type described by @var{type}, which must | |
19577 | be a @code{gdb.Type} object. If the cast cannot be performed for some | |
19578 | reason, this method throws an exception. | |
19579 | @end defmethod | |
19580 | ||
a08702d6 | 19581 | @defmethod Value dereference |
def2b000 TJB |
19582 | For pointer data types, this method returns a new @code{gdb.Value} object |
19583 | whose contents is the object pointed to by the pointer. For example, if | |
19584 | @code{foo} is a C pointer to an @code{int}, declared in your C program as | |
a08702d6 TJB |
19585 | |
19586 | @smallexample | |
19587 | int *foo; | |
19588 | @end smallexample | |
19589 | ||
19590 | @noindent | |
19591 | then you can use the corresponding @code{gdb.Value} to access what | |
19592 | @code{foo} points to like this: | |
19593 | ||
19594 | @smallexample | |
19595 | bar = foo.dereference () | |
19596 | @end smallexample | |
19597 | ||
19598 | The result @code{bar} will be a @code{gdb.Value} object holding the | |
19599 | value pointed to by @code{foo}. | |
19600 | @end defmethod | |
19601 | ||
fbb8f299 | 19602 | @defmethod Value string @r{[}encoding@r{]} @r{[}errors@r{]} @r{[}length@r{]} |
b6cb8e7d TJB |
19603 | If this @code{gdb.Value} represents a string, then this method |
19604 | converts the contents to a Python string. Otherwise, this method will | |
19605 | throw an exception. | |
19606 | ||
19607 | Strings are recognized in a language-specific way; whether a given | |
19608 | @code{gdb.Value} represents a string is determined by the current | |
19609 | language. | |
19610 | ||
19611 | For C-like languages, a value is a string if it is a pointer to or an | |
19612 | array of characters or ints. The string is assumed to be terminated | |
fbb8f299 PM |
19613 | by a zero of the appropriate width. However if the optional length |
19614 | argument is given, the string will be converted to that given length, | |
19615 | ignoring any embedded zeros that the string may contain. | |
b6cb8e7d TJB |
19616 | |
19617 | If the optional @var{encoding} argument is given, it must be a string | |
19618 | naming the encoding of the string in the @code{gdb.Value}, such as | |
19619 | @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. It accepts | |
19620 | the same encodings as the corresponding argument to Python's | |
19621 | @code{string.decode} method, and the Python codec machinery will be used | |
19622 | to convert the string. If @var{encoding} is not given, or if | |
19623 | @var{encoding} is the empty string, then either the @code{target-charset} | |
19624 | (@pxref{Character Sets}) will be used, or a language-specific encoding | |
19625 | will be used, if the current language is able to supply one. | |
19626 | ||
19627 | The optional @var{errors} argument is the same as the corresponding | |
19628 | argument to Python's @code{string.decode} method. | |
fbb8f299 PM |
19629 | |
19630 | If the optional @var{length} argument is given, the string will be | |
19631 | fetched and converted to the given length. | |
b6cb8e7d | 19632 | @end defmethod |
def2b000 | 19633 | @end table |
b6cb8e7d | 19634 | |
2c74e833 TT |
19635 | @node Types In Python |
19636 | @subsubsection Types In Python | |
19637 | @cindex types in Python | |
19638 | @cindex Python, working with types | |
19639 | ||
19640 | @tindex gdb.Type | |
19641 | @value{GDBN} represents types from the inferior using the class | |
19642 | @code{gdb.Type}. | |
19643 | ||
19644 | The following type-related functions are available in the @code{gdb} | |
19645 | module: | |
19646 | ||
19647 | @findex gdb.lookup_type | |
19648 | @defun lookup_type name [block] | |
19649 | This function looks up a type by name. @var{name} is the name of the | |
19650 | type to look up. It must be a string. | |
19651 | ||
19652 | Ordinarily, this function will return an instance of @code{gdb.Type}. | |
19653 | If the named type cannot be found, it will throw an exception. | |
19654 | @end defun | |
19655 | ||
19656 | An instance of @code{Type} has the following attributes: | |
19657 | ||
19658 | @table @code | |
19659 | @defivar Type code | |
19660 | The type code for this type. The type code will be one of the | |
19661 | @code{TYPE_CODE_} constants defined below. | |
19662 | @end defivar | |
19663 | ||
19664 | @defivar Type sizeof | |
19665 | The size of this type, in target @code{char} units. Usually, a | |
19666 | target's @code{char} type will be an 8-bit byte. However, on some | |
19667 | unusual platforms, this type may have a different size. | |
19668 | @end defivar | |
19669 | ||
19670 | @defivar Type tag | |
19671 | The tag name for this type. The tag name is the name after | |
19672 | @code{struct}, @code{union}, or @code{enum} in C and C@t{++}; not all | |
19673 | languages have this concept. If this type has no tag name, then | |
19674 | @code{None} is returned. | |
19675 | @end defivar | |
19676 | @end table | |
19677 | ||
19678 | The following methods are provided: | |
19679 | ||
19680 | @table @code | |
19681 | @defmethod Type fields | |
19682 | For structure and union types, this method returns the fields. Range | |
19683 | types have two fields, the minimum and maximum values. Enum types | |
19684 | have one field per enum constant. Function and method types have one | |
19685 | field per parameter. The base types of C@t{++} classes are also | |
19686 | represented as fields. If the type has no fields, or does not fit | |
19687 | into one of these categories, an empty sequence will be returned. | |
19688 | ||
19689 | Each field is an object, with some pre-defined attributes: | |
19690 | @table @code | |
19691 | @item bitpos | |
19692 | This attribute is not available for @code{static} fields (as in | |
19693 | C@t{++} or Java). For non-@code{static} fields, the value is the bit | |
19694 | position of the field. | |
19695 | ||
19696 | @item name | |
19697 | The name of the field, or @code{None} for anonymous fields. | |
19698 | ||
19699 | @item artificial | |
19700 | This is @code{True} if the field is artificial, usually meaning that | |
19701 | it was provided by the compiler and not the user. This attribute is | |
19702 | always provided, and is @code{False} if the field is not artificial. | |
19703 | ||
bfd31e71 PM |
19704 | @item is_base_class |
19705 | This is @code{True} if the field represents a base class of a C@t{++} | |
19706 | structure. This attribute is always provided, and is @code{False} | |
19707 | if the field is not a base class of the type that is the argument of | |
19708 | @code{fields}, or if that type was not a C@t{++} class. | |
19709 | ||
2c74e833 TT |
19710 | @item bitsize |
19711 | If the field is packed, or is a bitfield, then this will have a | |
19712 | non-zero value, which is the size of the field in bits. Otherwise, | |
19713 | this will be zero; in this case the field's size is given by its type. | |
19714 | ||
19715 | @item type | |
19716 | The type of the field. This is usually an instance of @code{Type}, | |
19717 | but it can be @code{None} in some situations. | |
19718 | @end table | |
19719 | @end defmethod | |
19720 | ||
19721 | @defmethod Type const | |
19722 | Return a new @code{gdb.Type} object which represents a | |
19723 | @code{const}-qualified variant of this type. | |
19724 | @end defmethod | |
19725 | ||
19726 | @defmethod Type volatile | |
19727 | Return a new @code{gdb.Type} object which represents a | |
19728 | @code{volatile}-qualified variant of this type. | |
19729 | @end defmethod | |
19730 | ||
19731 | @defmethod Type unqualified | |
19732 | Return a new @code{gdb.Type} object which represents an unqualified | |
19733 | variant of this type. That is, the result is neither @code{const} nor | |
19734 | @code{volatile}. | |
19735 | @end defmethod | |
19736 | ||
361ae042 PM |
19737 | @defmethod Type range |
19738 | Return a Python @code{Tuple} object that contains two elements: the | |
19739 | low bound of the argument type and the high bound of that type. If | |
19740 | the type does not have a range, @value{GDBN} will raise a | |
19741 | @code{RuntimeError} exception. | |
19742 | @end defmethod | |
19743 | ||
2c74e833 TT |
19744 | @defmethod Type reference |
19745 | Return a new @code{gdb.Type} object which represents a reference to this | |
19746 | type. | |
19747 | @end defmethod | |
19748 | ||
7a6973ad TT |
19749 | @defmethod Type pointer |
19750 | Return a new @code{gdb.Type} object which represents a pointer to this | |
19751 | type. | |
19752 | @end defmethod | |
19753 | ||
2c74e833 TT |
19754 | @defmethod Type strip_typedefs |
19755 | Return a new @code{gdb.Type} that represents the real type, | |
19756 | after removing all layers of typedefs. | |
19757 | @end defmethod | |
19758 | ||
19759 | @defmethod Type target | |
19760 | Return a new @code{gdb.Type} object which represents the target type | |
19761 | of this type. | |
19762 | ||
19763 | For a pointer type, the target type is the type of the pointed-to | |
19764 | object. For an array type (meaning C-like arrays), the target type is | |
19765 | the type of the elements of the array. For a function or method type, | |
19766 | the target type is the type of the return value. For a complex type, | |
19767 | the target type is the type of the elements. For a typedef, the | |
19768 | target type is the aliased type. | |
19769 | ||
19770 | If the type does not have a target, this method will throw an | |
19771 | exception. | |
19772 | @end defmethod | |
19773 | ||
19774 | @defmethod Type template_argument n | |
19775 | If this @code{gdb.Type} is an instantiation of a template, this will | |
19776 | return a new @code{gdb.Type} which represents the type of the | |
19777 | @var{n}th template argument. | |
19778 | ||
19779 | If this @code{gdb.Type} is not a template type, this will throw an | |
19780 | exception. Ordinarily, only C@t{++} code will have template types. | |
19781 | ||
19782 | @var{name} is searched for globally. | |
19783 | @end defmethod | |
19784 | @end table | |
19785 | ||
19786 | ||
19787 | Each type has a code, which indicates what category this type falls | |
19788 | into. The available type categories are represented by constants | |
19789 | defined in the @code{gdb} module: | |
19790 | ||
19791 | @table @code | |
19792 | @findex TYPE_CODE_PTR | |
19793 | @findex gdb.TYPE_CODE_PTR | |
19794 | @item TYPE_CODE_PTR | |
19795 | The type is a pointer. | |
19796 | ||
19797 | @findex TYPE_CODE_ARRAY | |
19798 | @findex gdb.TYPE_CODE_ARRAY | |
19799 | @item TYPE_CODE_ARRAY | |
19800 | The type is an array. | |
19801 | ||
19802 | @findex TYPE_CODE_STRUCT | |
19803 | @findex gdb.TYPE_CODE_STRUCT | |
19804 | @item TYPE_CODE_STRUCT | |
19805 | The type is a structure. | |
19806 | ||
19807 | @findex TYPE_CODE_UNION | |
19808 | @findex gdb.TYPE_CODE_UNION | |
19809 | @item TYPE_CODE_UNION | |
19810 | The type is a union. | |
19811 | ||
19812 | @findex TYPE_CODE_ENUM | |
19813 | @findex gdb.TYPE_CODE_ENUM | |
19814 | @item TYPE_CODE_ENUM | |
19815 | The type is an enum. | |
19816 | ||
19817 | @findex TYPE_CODE_FLAGS | |
19818 | @findex gdb.TYPE_CODE_FLAGS | |
19819 | @item TYPE_CODE_FLAGS | |
19820 | A bit flags type, used for things such as status registers. | |
19821 | ||
19822 | @findex TYPE_CODE_FUNC | |
19823 | @findex gdb.TYPE_CODE_FUNC | |
19824 | @item TYPE_CODE_FUNC | |
19825 | The type is a function. | |
19826 | ||
19827 | @findex TYPE_CODE_INT | |
19828 | @findex gdb.TYPE_CODE_INT | |
19829 | @item TYPE_CODE_INT | |
19830 | The type is an integer type. | |
19831 | ||
19832 | @findex TYPE_CODE_FLT | |
19833 | @findex gdb.TYPE_CODE_FLT | |
19834 | @item TYPE_CODE_FLT | |
19835 | A floating point type. | |
19836 | ||
19837 | @findex TYPE_CODE_VOID | |
19838 | @findex gdb.TYPE_CODE_VOID | |
19839 | @item TYPE_CODE_VOID | |
19840 | The special type @code{void}. | |
19841 | ||
19842 | @findex TYPE_CODE_SET | |
19843 | @findex gdb.TYPE_CODE_SET | |
19844 | @item TYPE_CODE_SET | |
19845 | A Pascal set type. | |
19846 | ||
19847 | @findex TYPE_CODE_RANGE | |
19848 | @findex gdb.TYPE_CODE_RANGE | |
19849 | @item TYPE_CODE_RANGE | |
19850 | A range type, that is, an integer type with bounds. | |
19851 | ||
19852 | @findex TYPE_CODE_STRING | |
19853 | @findex gdb.TYPE_CODE_STRING | |
19854 | @item TYPE_CODE_STRING | |
19855 | A string type. Note that this is only used for certain languages with | |
19856 | language-defined string types; C strings are not represented this way. | |
19857 | ||
19858 | @findex TYPE_CODE_BITSTRING | |
19859 | @findex gdb.TYPE_CODE_BITSTRING | |
19860 | @item TYPE_CODE_BITSTRING | |
19861 | A string of bits. | |
19862 | ||
19863 | @findex TYPE_CODE_ERROR | |
19864 | @findex gdb.TYPE_CODE_ERROR | |
19865 | @item TYPE_CODE_ERROR | |
19866 | An unknown or erroneous type. | |
19867 | ||
19868 | @findex TYPE_CODE_METHOD | |
19869 | @findex gdb.TYPE_CODE_METHOD | |
19870 | @item TYPE_CODE_METHOD | |
19871 | A method type, as found in C@t{++} or Java. | |
19872 | ||
19873 | @findex TYPE_CODE_METHODPTR | |
19874 | @findex gdb.TYPE_CODE_METHODPTR | |
19875 | @item TYPE_CODE_METHODPTR | |
19876 | A pointer-to-member-function. | |
19877 | ||
19878 | @findex TYPE_CODE_MEMBERPTR | |
19879 | @findex gdb.TYPE_CODE_MEMBERPTR | |
19880 | @item TYPE_CODE_MEMBERPTR | |
19881 | A pointer-to-member. | |
19882 | ||
19883 | @findex TYPE_CODE_REF | |
19884 | @findex gdb.TYPE_CODE_REF | |
19885 | @item TYPE_CODE_REF | |
19886 | A reference type. | |
19887 | ||
19888 | @findex TYPE_CODE_CHAR | |
19889 | @findex gdb.TYPE_CODE_CHAR | |
19890 | @item TYPE_CODE_CHAR | |
19891 | A character type. | |
19892 | ||
19893 | @findex TYPE_CODE_BOOL | |
19894 | @findex gdb.TYPE_CODE_BOOL | |
19895 | @item TYPE_CODE_BOOL | |
19896 | A boolean type. | |
19897 | ||
19898 | @findex TYPE_CODE_COMPLEX | |
19899 | @findex gdb.TYPE_CODE_COMPLEX | |
19900 | @item TYPE_CODE_COMPLEX | |
19901 | A complex float type. | |
19902 | ||
19903 | @findex TYPE_CODE_TYPEDEF | |
19904 | @findex gdb.TYPE_CODE_TYPEDEF | |
19905 | @item TYPE_CODE_TYPEDEF | |
19906 | A typedef to some other type. | |
19907 | ||
19908 | @findex TYPE_CODE_NAMESPACE | |
19909 | @findex gdb.TYPE_CODE_NAMESPACE | |
19910 | @item TYPE_CODE_NAMESPACE | |
19911 | A C@t{++} namespace. | |
19912 | ||
19913 | @findex TYPE_CODE_DECFLOAT | |
19914 | @findex gdb.TYPE_CODE_DECFLOAT | |
19915 | @item TYPE_CODE_DECFLOAT | |
19916 | A decimal floating point type. | |
19917 | ||
19918 | @findex TYPE_CODE_INTERNAL_FUNCTION | |
19919 | @findex gdb.TYPE_CODE_INTERNAL_FUNCTION | |
19920 | @item TYPE_CODE_INTERNAL_FUNCTION | |
19921 | A function internal to @value{GDBN}. This is the type used to represent | |
19922 | convenience functions. | |
19923 | @end table | |
19924 | ||
a6bac58e TT |
19925 | @node Pretty Printing |
19926 | @subsubsection Pretty Printing | |
19927 | ||
19928 | @value{GDBN} provides a mechanism to allow pretty-printing of values | |
19929 | using Python code. The pretty-printer API allows application-specific | |
19930 | code to greatly simplify the display of complex objects. This | |
19931 | mechanism works for both MI and the CLI. | |
19932 | ||
19933 | For example, here is how a C@t{++} @code{std::string} looks without a | |
19934 | pretty-printer: | |
19935 | ||
19936 | @smallexample | |
19937 | (@value{GDBP}) print s | |
19938 | $1 = @{ | |
19939 | static npos = 4294967295, | |
19940 | _M_dataplus = @{ | |
19941 | <std::allocator<char>> = @{ | |
19942 | <__gnu_cxx::new_allocator<char>> = @{<No data fields>@}, <No data fields>@}, | |
19943 | members of std::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider: | |
19944 | _M_p = 0x804a014 "abcd" | |
19945 | @} | |
19946 | @} | |
19947 | @end smallexample | |
19948 | ||
19949 | After a pretty-printer for @code{std::string} has been installed, only | |
19950 | the contents are printed: | |
19951 | ||
19952 | @smallexample | |
19953 | (@value{GDBP}) print s | |
19954 | $2 = "abcd" | |
19955 | @end smallexample | |
19956 | ||
19957 | A pretty-printer is just an object that holds a value and implements a | |
19958 | specific interface, defined here. | |
19959 | ||
19960 | @defop Operation {pretty printer} children (self) | |
19961 | @value{GDBN} will call this method on a pretty-printer to compute the | |
19962 | children of the pretty-printer's value. | |
19963 | ||
19964 | This method must return an object conforming to the Python iterator | |
19965 | protocol. Each item returned by the iterator must be a tuple holding | |
19966 | two elements. The first element is the ``name'' of the child; the | |
19967 | second element is the child's value. The value can be any Python | |
19968 | object which is convertible to a @value{GDBN} value. | |
19969 | ||
19970 | This method is optional. If it does not exist, @value{GDBN} will act | |
19971 | as though the value has no children. | |
19972 | @end defop | |
19973 | ||
19974 | @defop Operation {pretty printer} display_hint (self) | |
19975 | The CLI may call this method and use its result to change the | |
19976 | formatting of a value. The result will also be supplied to an MI | |
19977 | consumer as a @samp{displayhint} attribute of the variable being | |
19978 | printed. | |
19979 | ||
19980 | This method is optional. If it does exist, this method must return a | |
19981 | string. | |
19982 | ||
19983 | Some display hints are predefined by @value{GDBN}: | |
19984 | ||
19985 | @table @samp | |
19986 | @item array | |
19987 | Indicate that the object being printed is ``array-like''. The CLI | |
19988 | uses this to respect parameters such as @code{set print elements} and | |
19989 | @code{set print array}. | |
19990 | ||
19991 | @item map | |
19992 | Indicate that the object being printed is ``map-like'', and that the | |
19993 | children of this value can be assumed to alternate between keys and | |
19994 | values. | |
19995 | ||
19996 | @item string | |
19997 | Indicate that the object being printed is ``string-like''. If the | |
19998 | printer's @code{to_string} method returns a Python string of some | |
19999 | kind, then @value{GDBN} will call its internal language-specific | |
20000 | string-printing function to format the string. For the CLI this means | |
20001 | adding quotation marks, possibly escaping some characters, respecting | |
20002 | @code{set print elements}, and the like. | |
20003 | @end table | |
20004 | @end defop | |
20005 | ||
20006 | @defop Operation {pretty printer} to_string (self) | |
20007 | @value{GDBN} will call this method to display the string | |
20008 | representation of the value passed to the object's constructor. | |
20009 | ||
20010 | When printing from the CLI, if the @code{to_string} method exists, | |
20011 | then @value{GDBN} will prepend its result to the values returned by | |
20012 | @code{children}. Exactly how this formatting is done is dependent on | |
20013 | the display hint, and may change as more hints are added. Also, | |
20014 | depending on the print settings (@pxref{Print Settings}), the CLI may | |
20015 | print just the result of @code{to_string} in a stack trace, omitting | |
20016 | the result of @code{children}. | |
20017 | ||
20018 | If this method returns a string, it is printed verbatim. | |
20019 | ||
20020 | Otherwise, if this method returns an instance of @code{gdb.Value}, | |
20021 | then @value{GDBN} prints this value. This may result in a call to | |
20022 | another pretty-printer. | |
20023 | ||
20024 | If instead the method returns a Python value which is convertible to a | |
20025 | @code{gdb.Value}, then @value{GDBN} performs the conversion and prints | |
20026 | the resulting value. Again, this may result in a call to another | |
20027 | pretty-printer. Python scalars (integers, floats, and booleans) and | |
20028 | strings are convertible to @code{gdb.Value}; other types are not. | |
20029 | ||
20030 | If the result is not one of these types, an exception is raised. | |
20031 | @end defop | |
20032 | ||
20033 | @node Selecting Pretty-Printers | |
20034 | @subsubsection Selecting Pretty-Printers | |
20035 | ||
20036 | The Python list @code{gdb.pretty_printers} contains an array of | |
20037 | functions that have been registered via addition as a pretty-printer. | |
20038 | Each @code{gdb.Objfile} also contains a @code{pretty_printers} | |
20039 | attribute. | |
20040 | ||
20041 | A function on one of these lists is passed a single @code{gdb.Value} | |
20042 | argument and should return a pretty-printer object conforming to the | |
20043 | interface definition above (@pxref{Pretty Printing}). If a function | |
20044 | cannot create a pretty-printer for the value, it should return | |
20045 | @code{None}. | |
20046 | ||
20047 | @value{GDBN} first checks the @code{pretty_printers} attribute of each | |
20048 | @code{gdb.Objfile} and iteratively calls each function in the list for | |
20049 | that @code{gdb.Objfile} until it receives a pretty-printer object. | |
20050 | After these lists have been exhausted, it tries the global | |
20051 | @code{gdb.pretty-printers} list, again calling each function until an | |
20052 | object is returned. | |
20053 | ||
20054 | The order in which the objfiles are searched is not specified. For a | |
20055 | given list, functions are always invoked from the head of the list, | |
20056 | and iterated over sequentially until the end of the list, or a printer | |
20057 | object is returned. | |
20058 | ||
20059 | Here is an example showing how a @code{std::string} printer might be | |
20060 | written: | |
20061 | ||
20062 | @smallexample | |
20063 | class StdStringPrinter: | |
20064 | "Print a std::string" | |
20065 | ||
20066 | def __init__ (self, val): | |
20067 | self.val = val | |
20068 | ||
20069 | def to_string (self): | |
20070 | return self.val['_M_dataplus']['_M_p'] | |
20071 | ||
20072 | def display_hint (self): | |
20073 | return 'string' | |
20074 | @end smallexample | |
20075 | ||
20076 | And here is an example showing how a lookup function for the printer | |
20077 | example above might be written. | |
20078 | ||
20079 | @smallexample | |
20080 | def str_lookup_function (val): | |
20081 | ||
20082 | lookup_tag = val.type.tag | |
20083 | regex = re.compile ("^std::basic_string<char,.*>$") | |
20084 | if lookup_tag == None: | |
20085 | return None | |
20086 | if regex.match (lookup_tag): | |
20087 | return StdStringPrinter (val) | |
20088 | ||
20089 | return None | |
20090 | @end smallexample | |
20091 | ||
20092 | The example lookup function extracts the value's type, and attempts to | |
20093 | match it to a type that it can pretty-print. If it is a type the | |
20094 | printer can pretty-print, it will return a printer object. If not, it | |
20095 | returns @code{None}. | |
20096 | ||
20097 | We recommend that you put your core pretty-printers into a Python | |
20098 | package. If your pretty-printers are for use with a library, we | |
20099 | further recommend embedding a version number into the package name. | |
20100 | This practice will enable @value{GDBN} to load multiple versions of | |
20101 | your pretty-printers at the same time, because they will have | |
20102 | different names. | |
20103 | ||
20104 | You should write auto-loaded code (@pxref{Auto-loading}) such that it | |
20105 | can be evaluated multiple times without changing its meaning. An | |
20106 | ideal auto-load file will consist solely of @code{import}s of your | |
20107 | printer modules, followed by a call to a register pretty-printers with | |
20108 | the current objfile. | |
20109 | ||
20110 | Taken as a whole, this approach will scale nicely to multiple | |
20111 | inferiors, each potentially using a different library version. | |
20112 | Embedding a version number in the Python package name will ensure that | |
20113 | @value{GDBN} is able to load both sets of printers simultaneously. | |
20114 | Then, because the search for pretty-printers is done by objfile, and | |
20115 | because your auto-loaded code took care to register your library's | |
20116 | printers with a specific objfile, @value{GDBN} will find the correct | |
20117 | printers for the specific version of the library used by each | |
20118 | inferior. | |
20119 | ||
20120 | To continue the @code{std::string} example (@pxref{Pretty Printing}), | |
20121 | this code might appear in @code{gdb.libstdcxx.v6}: | |
20122 | ||
20123 | @smallexample | |
20124 | def register_printers (objfile): | |
20125 | objfile.pretty_printers.add (str_lookup_function) | |
20126 | @end smallexample | |
20127 | ||
20128 | @noindent | |
20129 | And then the corresponding contents of the auto-load file would be: | |
20130 | ||
20131 | @smallexample | |
20132 | import gdb.libstdcxx.v6 | |
20133 | gdb.libstdcxx.v6.register_printers (gdb.current_objfile ()) | |
20134 | @end smallexample | |
20135 | ||
d8906c6f TJB |
20136 | @node Commands In Python |
20137 | @subsubsection Commands In Python | |
20138 | ||
20139 | @cindex commands in python | |
20140 | @cindex python commands | |
d8906c6f TJB |
20141 | You can implement new @value{GDBN} CLI commands in Python. A CLI |
20142 | command is implemented using an instance of the @code{gdb.Command} | |
20143 | class, most commonly using a subclass. | |
20144 | ||
cc924cad | 20145 | @defmethod Command __init__ name @var{command_class} @r{[}@var{completer_class}@r{]} @r{[}@var{prefix}@r{]} |
d8906c6f TJB |
20146 | The object initializer for @code{Command} registers the new command |
20147 | with @value{GDBN}. This initializer is normally invoked from the | |
20148 | subclass' own @code{__init__} method. | |
20149 | ||
20150 | @var{name} is the name of the command. If @var{name} consists of | |
20151 | multiple words, then the initial words are looked for as prefix | |
20152 | commands. In this case, if one of the prefix commands does not exist, | |
20153 | an exception is raised. | |
20154 | ||
20155 | There is no support for multi-line commands. | |
20156 | ||
cc924cad | 20157 | @var{command_class} should be one of the @samp{COMMAND_} constants |
d8906c6f TJB |
20158 | defined below. This argument tells @value{GDBN} how to categorize the |
20159 | new command in the help system. | |
20160 | ||
cc924cad | 20161 | @var{completer_class} is an optional argument. If given, it should be |
d8906c6f TJB |
20162 | one of the @samp{COMPLETE_} constants defined below. This argument |
20163 | tells @value{GDBN} how to perform completion for this command. If not | |
20164 | given, @value{GDBN} will attempt to complete using the object's | |
20165 | @code{complete} method (see below); if no such method is found, an | |
20166 | error will occur when completion is attempted. | |
20167 | ||
20168 | @var{prefix} is an optional argument. If @code{True}, then the new | |
20169 | command is a prefix command; sub-commands of this command may be | |
20170 | registered. | |
20171 | ||
20172 | The help text for the new command is taken from the Python | |
20173 | documentation string for the command's class, if there is one. If no | |
20174 | documentation string is provided, the default value ``This command is | |
20175 | not documented.'' is used. | |
20176 | @end defmethod | |
20177 | ||
a0c36267 | 20178 | @cindex don't repeat Python command |
d8906c6f TJB |
20179 | @defmethod Command dont_repeat |
20180 | By default, a @value{GDBN} command is repeated when the user enters a | |
20181 | blank line at the command prompt. A command can suppress this | |
20182 | behavior by invoking the @code{dont_repeat} method. This is similar | |
20183 | to the user command @code{dont-repeat}, see @ref{Define, dont-repeat}. | |
20184 | @end defmethod | |
20185 | ||
20186 | @defmethod Command invoke argument from_tty | |
20187 | This method is called by @value{GDBN} when this command is invoked. | |
20188 | ||
20189 | @var{argument} is a string. It is the argument to the command, after | |
20190 | leading and trailing whitespace has been stripped. | |
20191 | ||
20192 | @var{from_tty} is a boolean argument. When true, this means that the | |
20193 | command was entered by the user at the terminal; when false it means | |
20194 | that the command came from elsewhere. | |
20195 | ||
20196 | If this method throws an exception, it is turned into a @value{GDBN} | |
20197 | @code{error} call. Otherwise, the return value is ignored. | |
20198 | @end defmethod | |
20199 | ||
a0c36267 | 20200 | @cindex completion of Python commands |
d8906c6f TJB |
20201 | @defmethod Command complete text word |
20202 | This method is called by @value{GDBN} when the user attempts | |
20203 | completion on this command. All forms of completion are handled by | |
a0c36267 EZ |
20204 | this method, that is, the @key{TAB} and @key{M-?} key bindings |
20205 | (@pxref{Completion}), and the @code{complete} command (@pxref{Help, | |
20206 | complete}). | |
d8906c6f TJB |
20207 | |
20208 | The arguments @var{text} and @var{word} are both strings. @var{text} | |
20209 | holds the complete command line up to the cursor's location. | |
20210 | @var{word} holds the last word of the command line; this is computed | |
20211 | using a word-breaking heuristic. | |
20212 | ||
20213 | The @code{complete} method can return several values: | |
20214 | @itemize @bullet | |
20215 | @item | |
20216 | If the return value is a sequence, the contents of the sequence are | |
20217 | used as the completions. It is up to @code{complete} to ensure that the | |
20218 | contents actually do complete the word. A zero-length sequence is | |
20219 | allowed, it means that there were no completions available. Only | |
20220 | string elements of the sequence are used; other elements in the | |
20221 | sequence are ignored. | |
20222 | ||
20223 | @item | |
20224 | If the return value is one of the @samp{COMPLETE_} constants defined | |
20225 | below, then the corresponding @value{GDBN}-internal completion | |
20226 | function is invoked, and its result is used. | |
20227 | ||
20228 | @item | |
20229 | All other results are treated as though there were no available | |
20230 | completions. | |
20231 | @end itemize | |
20232 | @end defmethod | |
20233 | ||
d8906c6f TJB |
20234 | When a new command is registered, it must be declared as a member of |
20235 | some general class of commands. This is used to classify top-level | |
20236 | commands in the on-line help system; note that prefix commands are not | |
20237 | listed under their own category but rather that of their top-level | |
20238 | command. The available classifications are represented by constants | |
20239 | defined in the @code{gdb} module: | |
20240 | ||
20241 | @table @code | |
20242 | @findex COMMAND_NONE | |
20243 | @findex gdb.COMMAND_NONE | |
20244 | @item COMMAND_NONE | |
20245 | The command does not belong to any particular class. A command in | |
20246 | this category will not be displayed in any of the help categories. | |
20247 | ||
20248 | @findex COMMAND_RUNNING | |
20249 | @findex gdb.COMMAND_RUNNING | |
a0c36267 | 20250 | @item COMMAND_RUNNING |
d8906c6f TJB |
20251 | The command is related to running the inferior. For example, |
20252 | @code{start}, @code{step}, and @code{continue} are in this category. | |
a0c36267 | 20253 | Type @kbd{help running} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
20254 | commands in this category. |
20255 | ||
20256 | @findex COMMAND_DATA | |
20257 | @findex gdb.COMMAND_DATA | |
a0c36267 | 20258 | @item COMMAND_DATA |
d8906c6f TJB |
20259 | The command is related to data or variables. For example, |
20260 | @code{call}, @code{find}, and @code{print} are in this category. Type | |
a0c36267 | 20261 | @kbd{help data} at the @value{GDBN} prompt to see a list of commands |
d8906c6f TJB |
20262 | in this category. |
20263 | ||
20264 | @findex COMMAND_STACK | |
20265 | @findex gdb.COMMAND_STACK | |
20266 | @item COMMAND_STACK | |
20267 | The command has to do with manipulation of the stack. For example, | |
20268 | @code{backtrace}, @code{frame}, and @code{return} are in this | |
a0c36267 | 20269 | category. Type @kbd{help stack} at the @value{GDBN} prompt to see a |
d8906c6f TJB |
20270 | list of commands in this category. |
20271 | ||
20272 | @findex COMMAND_FILES | |
20273 | @findex gdb.COMMAND_FILES | |
20274 | @item COMMAND_FILES | |
20275 | This class is used for file-related commands. For example, | |
20276 | @code{file}, @code{list} and @code{section} are in this category. | |
a0c36267 | 20277 | Type @kbd{help files} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
20278 | commands in this category. |
20279 | ||
20280 | @findex COMMAND_SUPPORT | |
20281 | @findex gdb.COMMAND_SUPPORT | |
20282 | @item COMMAND_SUPPORT | |
20283 | This should be used for ``support facilities'', generally meaning | |
20284 | things that are useful to the user when interacting with @value{GDBN}, | |
20285 | but not related to the state of the inferior. For example, | |
20286 | @code{help}, @code{make}, and @code{shell} are in this category. Type | |
a0c36267 | 20287 | @kbd{help support} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
20288 | commands in this category. |
20289 | ||
20290 | @findex COMMAND_STATUS | |
20291 | @findex gdb.COMMAND_STATUS | |
a0c36267 | 20292 | @item COMMAND_STATUS |
d8906c6f TJB |
20293 | The command is an @samp{info}-related command, that is, related to the |
20294 | state of @value{GDBN} itself. For example, @code{info}, @code{macro}, | |
a0c36267 | 20295 | and @code{show} are in this category. Type @kbd{help status} at the |
d8906c6f TJB |
20296 | @value{GDBN} prompt to see a list of commands in this category. |
20297 | ||
20298 | @findex COMMAND_BREAKPOINTS | |
20299 | @findex gdb.COMMAND_BREAKPOINTS | |
a0c36267 | 20300 | @item COMMAND_BREAKPOINTS |
d8906c6f | 20301 | The command has to do with breakpoints. For example, @code{break}, |
a0c36267 | 20302 | @code{clear}, and @code{delete} are in this category. Type @kbd{help |
d8906c6f TJB |
20303 | breakpoints} at the @value{GDBN} prompt to see a list of commands in |
20304 | this category. | |
20305 | ||
20306 | @findex COMMAND_TRACEPOINTS | |
20307 | @findex gdb.COMMAND_TRACEPOINTS | |
a0c36267 | 20308 | @item COMMAND_TRACEPOINTS |
d8906c6f TJB |
20309 | The command has to do with tracepoints. For example, @code{trace}, |
20310 | @code{actions}, and @code{tfind} are in this category. Type | |
a0c36267 | 20311 | @kbd{help tracepoints} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
20312 | commands in this category. |
20313 | ||
20314 | @findex COMMAND_OBSCURE | |
20315 | @findex gdb.COMMAND_OBSCURE | |
20316 | @item COMMAND_OBSCURE | |
20317 | The command is only used in unusual circumstances, or is not of | |
20318 | general interest to users. For example, @code{checkpoint}, | |
a0c36267 | 20319 | @code{fork}, and @code{stop} are in this category. Type @kbd{help |
d8906c6f TJB |
20320 | obscure} at the @value{GDBN} prompt to see a list of commands in this |
20321 | category. | |
20322 | ||
20323 | @findex COMMAND_MAINTENANCE | |
20324 | @findex gdb.COMMAND_MAINTENANCE | |
20325 | @item COMMAND_MAINTENANCE | |
20326 | The command is only useful to @value{GDBN} maintainers. The | |
20327 | @code{maintenance} and @code{flushregs} commands are in this category. | |
a0c36267 | 20328 | Type @kbd{help internals} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
20329 | commands in this category. |
20330 | @end table | |
20331 | ||
d8906c6f TJB |
20332 | A new command can use a predefined completion function, either by |
20333 | specifying it via an argument at initialization, or by returning it | |
20334 | from the @code{complete} method. These predefined completion | |
20335 | constants are all defined in the @code{gdb} module: | |
20336 | ||
20337 | @table @code | |
20338 | @findex COMPLETE_NONE | |
20339 | @findex gdb.COMPLETE_NONE | |
20340 | @item COMPLETE_NONE | |
20341 | This constant means that no completion should be done. | |
20342 | ||
20343 | @findex COMPLETE_FILENAME | |
20344 | @findex gdb.COMPLETE_FILENAME | |
20345 | @item COMPLETE_FILENAME | |
20346 | This constant means that filename completion should be performed. | |
20347 | ||
20348 | @findex COMPLETE_LOCATION | |
20349 | @findex gdb.COMPLETE_LOCATION | |
20350 | @item COMPLETE_LOCATION | |
20351 | This constant means that location completion should be done. | |
20352 | @xref{Specify Location}. | |
20353 | ||
20354 | @findex COMPLETE_COMMAND | |
20355 | @findex gdb.COMPLETE_COMMAND | |
20356 | @item COMPLETE_COMMAND | |
20357 | This constant means that completion should examine @value{GDBN} | |
20358 | command names. | |
20359 | ||
20360 | @findex COMPLETE_SYMBOL | |
20361 | @findex gdb.COMPLETE_SYMBOL | |
20362 | @item COMPLETE_SYMBOL | |
20363 | This constant means that completion should be done using symbol names | |
20364 | as the source. | |
20365 | @end table | |
20366 | ||
20367 | The following code snippet shows how a trivial CLI command can be | |
20368 | implemented in Python: | |
20369 | ||
20370 | @smallexample | |
20371 | class HelloWorld (gdb.Command): | |
20372 | """Greet the whole world.""" | |
20373 | ||
20374 | def __init__ (self): | |
20375 | super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE) | |
20376 | ||
20377 | def invoke (self, arg, from_tty): | |
20378 | print "Hello, World!" | |
20379 | ||
20380 | HelloWorld () | |
20381 | @end smallexample | |
20382 | ||
20383 | The last line instantiates the class, and is necessary to trigger the | |
20384 | registration of the command with @value{GDBN}. Depending on how the | |
20385 | Python code is read into @value{GDBN}, you may need to import the | |
20386 | @code{gdb} module explicitly. | |
20387 | ||
bc3b79fd TJB |
20388 | @node Functions In Python |
20389 | @subsubsection Writing new convenience functions | |
20390 | ||
20391 | @cindex writing convenience functions | |
20392 | @cindex convenience functions in python | |
20393 | @cindex python convenience functions | |
20394 | @tindex gdb.Function | |
20395 | @tindex Function | |
20396 | You can implement new convenience functions (@pxref{Convenience Vars}) | |
20397 | in Python. A convenience function is an instance of a subclass of the | |
20398 | class @code{gdb.Function}. | |
20399 | ||
20400 | @defmethod Function __init__ name | |
20401 | The initializer for @code{Function} registers the new function with | |
20402 | @value{GDBN}. The argument @var{name} is the name of the function, | |
20403 | a string. The function will be visible to the user as a convenience | |
20404 | variable of type @code{internal function}, whose name is the same as | |
20405 | the given @var{name}. | |
20406 | ||
20407 | The documentation for the new function is taken from the documentation | |
20408 | string for the new class. | |
20409 | @end defmethod | |
20410 | ||
20411 | @defmethod Function invoke @var{*args} | |
20412 | When a convenience function is evaluated, its arguments are converted | |
20413 | to instances of @code{gdb.Value}, and then the function's | |
20414 | @code{invoke} method is called. Note that @value{GDBN} does not | |
20415 | predetermine the arity of convenience functions. Instead, all | |
20416 | available arguments are passed to @code{invoke}, following the | |
20417 | standard Python calling convention. In particular, a convenience | |
20418 | function can have default values for parameters without ill effect. | |
20419 | ||
20420 | The return value of this method is used as its value in the enclosing | |
20421 | expression. If an ordinary Python value is returned, it is converted | |
20422 | to a @code{gdb.Value} following the usual rules. | |
20423 | @end defmethod | |
20424 | ||
20425 | The following code snippet shows how a trivial convenience function can | |
20426 | be implemented in Python: | |
20427 | ||
20428 | @smallexample | |
20429 | class Greet (gdb.Function): | |
20430 | """Return string to greet someone. | |
20431 | Takes a name as argument.""" | |
20432 | ||
20433 | def __init__ (self): | |
20434 | super (Greet, self).__init__ ("greet") | |
20435 | ||
20436 | def invoke (self, name): | |
20437 | return "Hello, %s!" % name.string () | |
20438 | ||
20439 | Greet () | |
20440 | @end smallexample | |
20441 | ||
20442 | The last line instantiates the class, and is necessary to trigger the | |
20443 | registration of the function with @value{GDBN}. Depending on how the | |
20444 | Python code is read into @value{GDBN}, you may need to import the | |
20445 | @code{gdb} module explicitly. | |
20446 | ||
89c73ade TT |
20447 | @node Objfiles In Python |
20448 | @subsubsection Objfiles In Python | |
20449 | ||
20450 | @cindex objfiles in python | |
20451 | @tindex gdb.Objfile | |
20452 | @tindex Objfile | |
20453 | @value{GDBN} loads symbols for an inferior from various | |
20454 | symbol-containing files (@pxref{Files}). These include the primary | |
20455 | executable file, any shared libraries used by the inferior, and any | |
20456 | separate debug info files (@pxref{Separate Debug Files}). | |
20457 | @value{GDBN} calls these symbol-containing files @dfn{objfiles}. | |
20458 | ||
20459 | The following objfile-related functions are available in the | |
20460 | @code{gdb} module: | |
20461 | ||
20462 | @findex gdb.current_objfile | |
20463 | @defun current_objfile | |
20464 | When auto-loading a Python script (@pxref{Auto-loading}), @value{GDBN} | |
20465 | sets the ``current objfile'' to the corresponding objfile. This | |
20466 | function returns the current objfile. If there is no current objfile, | |
20467 | this function returns @code{None}. | |
20468 | @end defun | |
20469 | ||
20470 | @findex gdb.objfiles | |
20471 | @defun objfiles | |
20472 | Return a sequence of all the objfiles current known to @value{GDBN}. | |
20473 | @xref{Objfiles In Python}. | |
20474 | @end defun | |
20475 | ||
20476 | Each objfile is represented by an instance of the @code{gdb.Objfile} | |
20477 | class. | |
20478 | ||
20479 | @defivar Objfile filename | |
20480 | The file name of the objfile as a string. | |
20481 | @end defivar | |
20482 | ||
20483 | @defivar Objfile pretty_printers | |
20484 | The @code{pretty_printers} attribute is a list of functions. It is | |
20485 | used to look up pretty-printers. A @code{Value} is passed to each | |
20486 | function in order; if the function returns @code{None}, then the | |
20487 | search continues. Otherwise, the return value should be an object | |
a6bac58e TT |
20488 | which is used to format the value. @xref{Pretty Printing}, for more |
20489 | information. | |
89c73ade TT |
20490 | @end defivar |
20491 | ||
f8f6f20b TJB |
20492 | @node Frames In Python |
20493 | @subsubsection Acessing inferior stack frames from Python. | |
20494 | ||
20495 | @cindex frames in python | |
20496 | When the debugged program stops, @value{GDBN} is able to analyze its call | |
20497 | stack (@pxref{Frames,,Stack frames}). The @code{gdb.Frame} class | |
20498 | represents a frame in the stack. A @code{gdb.Frame} object is only valid | |
20499 | while its corresponding frame exists in the inferior's stack. If you try | |
20500 | to use an invalid frame object, @value{GDBN} will throw a @code{RuntimeError} | |
20501 | exception. | |
20502 | ||
20503 | Two @code{gdb.Frame} objects can be compared for equality with the @code{==} | |
20504 | operator, like: | |
20505 | ||
20506 | @smallexample | |
20507 | (@value{GDBP}) python print gdb.newest_frame() == gdb.selected_frame () | |
20508 | True | |
20509 | @end smallexample | |
20510 | ||
20511 | The following frame-related functions are available in the @code{gdb} module: | |
20512 | ||
20513 | @findex gdb.selected_frame | |
20514 | @defun selected_frame | |
20515 | Return the selected frame object. (@pxref{Selection,,Selecting a Frame}). | |
20516 | @end defun | |
20517 | ||
20518 | @defun frame_stop_reason_string reason | |
20519 | Return a string explaining the reason why @value{GDBN} stopped unwinding | |
20520 | frames, as expressed by the given @var{reason} code (an integer, see the | |
20521 | @code{unwind_stop_reason} method further down in this section). | |
20522 | @end defun | |
20523 | ||
20524 | A @code{gdb.Frame} object has the following methods: | |
20525 | ||
20526 | @table @code | |
20527 | @defmethod Frame is_valid | |
20528 | Returns true if the @code{gdb.Frame} object is valid, false if not. | |
20529 | A frame object can become invalid if the frame it refers to doesn't | |
20530 | exist anymore in the inferior. All @code{gdb.Frame} methods will throw | |
20531 | an exception if it is invalid at the time the method is called. | |
20532 | @end defmethod | |
20533 | ||
20534 | @defmethod Frame name | |
20535 | Returns the function name of the frame, or @code{None} if it can't be | |
20536 | obtained. | |
20537 | @end defmethod | |
20538 | ||
20539 | @defmethod Frame type | |
20540 | Returns the type of the frame. The value can be one of | |
20541 | @code{gdb.NORMAL_FRAME}, @code{gdb.DUMMY_FRAME}, @code{gdb.SIGTRAMP_FRAME} | |
20542 | or @code{gdb.SENTINEL_FRAME}. | |
20543 | @end defmethod | |
20544 | ||
20545 | @defmethod Frame unwind_stop_reason | |
20546 | Return an integer representing the reason why it's not possible to find | |
20547 | more frames toward the outermost frame. Use | |
20548 | @code{gdb.frame_stop_reason_string} to convert the value returned by this | |
20549 | function to a string. | |
20550 | @end defmethod | |
20551 | ||
20552 | @defmethod Frame pc | |
20553 | Returns the frame's resume address. | |
20554 | @end defmethod | |
20555 | ||
20556 | @defmethod Frame older | |
20557 | Return the frame that called this frame. | |
20558 | @end defmethod | |
20559 | ||
20560 | @defmethod Frame newer | |
20561 | Return the frame called by this frame. | |
20562 | @end defmethod | |
20563 | ||
20564 | @defmethod Frame read_var variable | |
20565 | Return the value of the given variable in this frame. @var{variable} must | |
20566 | be a string. | |
20567 | @end defmethod | |
20568 | @end table | |
20569 | ||
21c294e6 AC |
20570 | @node Interpreters |
20571 | @chapter Command Interpreters | |
20572 | @cindex command interpreters | |
20573 | ||
20574 | @value{GDBN} supports multiple command interpreters, and some command | |
20575 | infrastructure to allow users or user interface writers to switch | |
20576 | between interpreters or run commands in other interpreters. | |
20577 | ||
20578 | @value{GDBN} currently supports two command interpreters, the console | |
20579 | interpreter (sometimes called the command-line interpreter or @sc{cli}) | |
20580 | and the machine interface interpreter (or @sc{gdb/mi}). This manual | |
20581 | describes both of these interfaces in great detail. | |
20582 | ||
20583 | By default, @value{GDBN} will start with the console interpreter. | |
20584 | However, the user may choose to start @value{GDBN} with another | |
20585 | interpreter by specifying the @option{-i} or @option{--interpreter} | |
20586 | startup options. Defined interpreters include: | |
20587 | ||
20588 | @table @code | |
20589 | @item console | |
20590 | @cindex console interpreter | |
20591 | The traditional console or command-line interpreter. This is the most often | |
20592 | used interpreter with @value{GDBN}. With no interpreter specified at runtime, | |
20593 | @value{GDBN} will use this interpreter. | |
20594 | ||
20595 | @item mi | |
20596 | @cindex mi interpreter | |
20597 | The newest @sc{gdb/mi} interface (currently @code{mi2}). Used primarily | |
20598 | by programs wishing to use @value{GDBN} as a backend for a debugger GUI | |
20599 | or an IDE. For more information, see @ref{GDB/MI, ,The @sc{gdb/mi} | |
20600 | Interface}. | |
20601 | ||
20602 | @item mi2 | |
20603 | @cindex mi2 interpreter | |
20604 | The current @sc{gdb/mi} interface. | |
20605 | ||
20606 | @item mi1 | |
20607 | @cindex mi1 interpreter | |
20608 | The @sc{gdb/mi} interface included in @value{GDBN} 5.1, 5.2, and 5.3. | |
20609 | ||
20610 | @end table | |
20611 | ||
20612 | @cindex invoke another interpreter | |
20613 | The interpreter being used by @value{GDBN} may not be dynamically | |
20614 | switched at runtime. Although possible, this could lead to a very | |
20615 | precarious situation. Consider an IDE using @sc{gdb/mi}. If a user | |
20616 | enters the command "interpreter-set console" in a console view, | |
20617 | @value{GDBN} would switch to using the console interpreter, rendering | |
20618 | the IDE inoperable! | |
20619 | ||
20620 | @kindex interpreter-exec | |
20621 | Although you may only choose a single interpreter at startup, you may execute | |
20622 | commands in any interpreter from the current interpreter using the appropriate | |
20623 | command. If you are running the console interpreter, simply use the | |
20624 | @code{interpreter-exec} command: | |
20625 | ||
20626 | @smallexample | |
20627 | interpreter-exec mi "-data-list-register-names" | |
20628 | @end smallexample | |
20629 | ||
20630 | @sc{gdb/mi} has a similar command, although it is only available in versions of | |
20631 | @value{GDBN} which support @sc{gdb/mi} version 2 (or greater). | |
20632 | ||
8e04817f AC |
20633 | @node TUI |
20634 | @chapter @value{GDBN} Text User Interface | |
20635 | @cindex TUI | |
d0d5df6f | 20636 | @cindex Text User Interface |
c906108c | 20637 | |
8e04817f AC |
20638 | @menu |
20639 | * TUI Overview:: TUI overview | |
20640 | * TUI Keys:: TUI key bindings | |
7cf36c78 | 20641 | * TUI Single Key Mode:: TUI single key mode |
db2e3e2e | 20642 | * TUI Commands:: TUI-specific commands |
8e04817f AC |
20643 | * TUI Configuration:: TUI configuration variables |
20644 | @end menu | |
c906108c | 20645 | |
46ba6afa | 20646 | The @value{GDBN} Text User Interface (TUI) is a terminal |
d0d5df6f AC |
20647 | interface which uses the @code{curses} library to show the source |
20648 | file, the assembly output, the program registers and @value{GDBN} | |
46ba6afa BW |
20649 | commands in separate text windows. The TUI mode is supported only |
20650 | on platforms where a suitable version of the @code{curses} library | |
20651 | is available. | |
d0d5df6f | 20652 | |
46ba6afa BW |
20653 | @pindex @value{GDBTUI} |
20654 | The TUI mode is enabled by default when you invoke @value{GDBN} as | |
20655 | either @samp{@value{GDBTUI}} or @samp{@value{GDBP} -tui}. | |
20656 | You can also switch in and out of TUI mode while @value{GDBN} runs by | |
20657 | using various TUI commands and key bindings, such as @kbd{C-x C-a}. | |
20658 | @xref{TUI Keys, ,TUI Key Bindings}. | |
c906108c | 20659 | |
8e04817f | 20660 | @node TUI Overview |
79a6e687 | 20661 | @section TUI Overview |
c906108c | 20662 | |
46ba6afa | 20663 | In TUI mode, @value{GDBN} can display several text windows: |
c906108c | 20664 | |
8e04817f AC |
20665 | @table @emph |
20666 | @item command | |
20667 | This window is the @value{GDBN} command window with the @value{GDBN} | |
46ba6afa BW |
20668 | prompt and the @value{GDBN} output. The @value{GDBN} input is still |
20669 | managed using readline. | |
c906108c | 20670 | |
8e04817f AC |
20671 | @item source |
20672 | The source window shows the source file of the program. The current | |
46ba6afa | 20673 | line and active breakpoints are displayed in this window. |
c906108c | 20674 | |
8e04817f AC |
20675 | @item assembly |
20676 | The assembly window shows the disassembly output of the program. | |
c906108c | 20677 | |
8e04817f | 20678 | @item register |
46ba6afa BW |
20679 | This window shows the processor registers. Registers are highlighted |
20680 | when their values change. | |
c906108c SS |
20681 | @end table |
20682 | ||
269c21fe | 20683 | The source and assembly windows show the current program position |
46ba6afa BW |
20684 | by highlighting the current line and marking it with a @samp{>} marker. |
20685 | Breakpoints are indicated with two markers. The first marker | |
269c21fe SC |
20686 | indicates the breakpoint type: |
20687 | ||
20688 | @table @code | |
20689 | @item B | |
20690 | Breakpoint which was hit at least once. | |
20691 | ||
20692 | @item b | |
20693 | Breakpoint which was never hit. | |
20694 | ||
20695 | @item H | |
20696 | Hardware breakpoint which was hit at least once. | |
20697 | ||
20698 | @item h | |
20699 | Hardware breakpoint which was never hit. | |
269c21fe SC |
20700 | @end table |
20701 | ||
20702 | The second marker indicates whether the breakpoint is enabled or not: | |
20703 | ||
20704 | @table @code | |
20705 | @item + | |
20706 | Breakpoint is enabled. | |
20707 | ||
20708 | @item - | |
20709 | Breakpoint is disabled. | |
269c21fe SC |
20710 | @end table |
20711 | ||
46ba6afa BW |
20712 | The source, assembly and register windows are updated when the current |
20713 | thread changes, when the frame changes, or when the program counter | |
20714 | changes. | |
20715 | ||
20716 | These windows are not all visible at the same time. The command | |
20717 | window is always visible. The others can be arranged in several | |
20718 | layouts: | |
c906108c | 20719 | |
8e04817f AC |
20720 | @itemize @bullet |
20721 | @item | |
46ba6afa | 20722 | source only, |
2df3850c | 20723 | |
8e04817f | 20724 | @item |
46ba6afa | 20725 | assembly only, |
8e04817f AC |
20726 | |
20727 | @item | |
46ba6afa | 20728 | source and assembly, |
8e04817f AC |
20729 | |
20730 | @item | |
46ba6afa | 20731 | source and registers, or |
c906108c | 20732 | |
8e04817f | 20733 | @item |
46ba6afa | 20734 | assembly and registers. |
8e04817f | 20735 | @end itemize |
c906108c | 20736 | |
46ba6afa | 20737 | A status line above the command window shows the following information: |
b7bb15bc SC |
20738 | |
20739 | @table @emph | |
20740 | @item target | |
46ba6afa | 20741 | Indicates the current @value{GDBN} target. |
b7bb15bc SC |
20742 | (@pxref{Targets, ,Specifying a Debugging Target}). |
20743 | ||
20744 | @item process | |
46ba6afa | 20745 | Gives the current process or thread number. |
b7bb15bc SC |
20746 | When no process is being debugged, this field is set to @code{No process}. |
20747 | ||
20748 | @item function | |
20749 | Gives the current function name for the selected frame. | |
20750 | The name is demangled if demangling is turned on (@pxref{Print Settings}). | |
46ba6afa | 20751 | When there is no symbol corresponding to the current program counter, |
b7bb15bc SC |
20752 | the string @code{??} is displayed. |
20753 | ||
20754 | @item line | |
20755 | Indicates the current line number for the selected frame. | |
46ba6afa | 20756 | When the current line number is not known, the string @code{??} is displayed. |
b7bb15bc SC |
20757 | |
20758 | @item pc | |
20759 | Indicates the current program counter address. | |
b7bb15bc SC |
20760 | @end table |
20761 | ||
8e04817f AC |
20762 | @node TUI Keys |
20763 | @section TUI Key Bindings | |
20764 | @cindex TUI key bindings | |
c906108c | 20765 | |
8e04817f | 20766 | The TUI installs several key bindings in the readline keymaps |
46ba6afa | 20767 | (@pxref{Command Line Editing}). The following key bindings |
8e04817f | 20768 | are installed for both TUI mode and the @value{GDBN} standard mode. |
c906108c | 20769 | |
8e04817f AC |
20770 | @table @kbd |
20771 | @kindex C-x C-a | |
20772 | @item C-x C-a | |
20773 | @kindex C-x a | |
20774 | @itemx C-x a | |
20775 | @kindex C-x A | |
20776 | @itemx C-x A | |
46ba6afa BW |
20777 | Enter or leave the TUI mode. When leaving the TUI mode, |
20778 | the curses window management stops and @value{GDBN} operates using | |
20779 | its standard mode, writing on the terminal directly. When reentering | |
20780 | the TUI mode, control is given back to the curses windows. | |
8e04817f | 20781 | The screen is then refreshed. |
c906108c | 20782 | |
8e04817f AC |
20783 | @kindex C-x 1 |
20784 | @item C-x 1 | |
20785 | Use a TUI layout with only one window. The layout will | |
20786 | either be @samp{source} or @samp{assembly}. When the TUI mode | |
20787 | is not active, it will switch to the TUI mode. | |
2df3850c | 20788 | |
8e04817f | 20789 | Think of this key binding as the Emacs @kbd{C-x 1} binding. |
c906108c | 20790 | |
8e04817f AC |
20791 | @kindex C-x 2 |
20792 | @item C-x 2 | |
20793 | Use a TUI layout with at least two windows. When the current | |
46ba6afa | 20794 | layout already has two windows, the next layout with two windows is used. |
8e04817f AC |
20795 | When a new layout is chosen, one window will always be common to the |
20796 | previous layout and the new one. | |
c906108c | 20797 | |
8e04817f | 20798 | Think of it as the Emacs @kbd{C-x 2} binding. |
2df3850c | 20799 | |
72ffddc9 SC |
20800 | @kindex C-x o |
20801 | @item C-x o | |
20802 | Change the active window. The TUI associates several key bindings | |
46ba6afa | 20803 | (like scrolling and arrow keys) with the active window. This command |
72ffddc9 SC |
20804 | gives the focus to the next TUI window. |
20805 | ||
20806 | Think of it as the Emacs @kbd{C-x o} binding. | |
20807 | ||
7cf36c78 SC |
20808 | @kindex C-x s |
20809 | @item C-x s | |
46ba6afa BW |
20810 | Switch in and out of the TUI SingleKey mode that binds single |
20811 | keys to @value{GDBN} commands (@pxref{TUI Single Key Mode}). | |
c906108c SS |
20812 | @end table |
20813 | ||
46ba6afa | 20814 | The following key bindings only work in the TUI mode: |
5d161b24 | 20815 | |
46ba6afa | 20816 | @table @asis |
8e04817f | 20817 | @kindex PgUp |
46ba6afa | 20818 | @item @key{PgUp} |
8e04817f | 20819 | Scroll the active window one page up. |
c906108c | 20820 | |
8e04817f | 20821 | @kindex PgDn |
46ba6afa | 20822 | @item @key{PgDn} |
8e04817f | 20823 | Scroll the active window one page down. |
c906108c | 20824 | |
8e04817f | 20825 | @kindex Up |
46ba6afa | 20826 | @item @key{Up} |
8e04817f | 20827 | Scroll the active window one line up. |
c906108c | 20828 | |
8e04817f | 20829 | @kindex Down |
46ba6afa | 20830 | @item @key{Down} |
8e04817f | 20831 | Scroll the active window one line down. |
c906108c | 20832 | |
8e04817f | 20833 | @kindex Left |
46ba6afa | 20834 | @item @key{Left} |
8e04817f | 20835 | Scroll the active window one column left. |
c906108c | 20836 | |
8e04817f | 20837 | @kindex Right |
46ba6afa | 20838 | @item @key{Right} |
8e04817f | 20839 | Scroll the active window one column right. |
c906108c | 20840 | |
8e04817f | 20841 | @kindex C-L |
46ba6afa | 20842 | @item @kbd{C-L} |
8e04817f | 20843 | Refresh the screen. |
8e04817f | 20844 | @end table |
c906108c | 20845 | |
46ba6afa BW |
20846 | Because the arrow keys scroll the active window in the TUI mode, they |
20847 | are not available for their normal use by readline unless the command | |
20848 | window has the focus. When another window is active, you must use | |
20849 | other readline key bindings such as @kbd{C-p}, @kbd{C-n}, @kbd{C-b} | |
20850 | and @kbd{C-f} to control the command window. | |
8e04817f | 20851 | |
7cf36c78 SC |
20852 | @node TUI Single Key Mode |
20853 | @section TUI Single Key Mode | |
20854 | @cindex TUI single key mode | |
20855 | ||
46ba6afa BW |
20856 | The TUI also provides a @dfn{SingleKey} mode, which binds several |
20857 | frequently used @value{GDBN} commands to single keys. Type @kbd{C-x s} to | |
20858 | switch into this mode, where the following key bindings are used: | |
7cf36c78 SC |
20859 | |
20860 | @table @kbd | |
20861 | @kindex c @r{(SingleKey TUI key)} | |
20862 | @item c | |
20863 | continue | |
20864 | ||
20865 | @kindex d @r{(SingleKey TUI key)} | |
20866 | @item d | |
20867 | down | |
20868 | ||
20869 | @kindex f @r{(SingleKey TUI key)} | |
20870 | @item f | |
20871 | finish | |
20872 | ||
20873 | @kindex n @r{(SingleKey TUI key)} | |
20874 | @item n | |
20875 | next | |
20876 | ||
20877 | @kindex q @r{(SingleKey TUI key)} | |
20878 | @item q | |
46ba6afa | 20879 | exit the SingleKey mode. |
7cf36c78 SC |
20880 | |
20881 | @kindex r @r{(SingleKey TUI key)} | |
20882 | @item r | |
20883 | run | |
20884 | ||
20885 | @kindex s @r{(SingleKey TUI key)} | |
20886 | @item s | |
20887 | step | |
20888 | ||
20889 | @kindex u @r{(SingleKey TUI key)} | |
20890 | @item u | |
20891 | up | |
20892 | ||
20893 | @kindex v @r{(SingleKey TUI key)} | |
20894 | @item v | |
20895 | info locals | |
20896 | ||
20897 | @kindex w @r{(SingleKey TUI key)} | |
20898 | @item w | |
20899 | where | |
7cf36c78 SC |
20900 | @end table |
20901 | ||
20902 | Other keys temporarily switch to the @value{GDBN} command prompt. | |
20903 | The key that was pressed is inserted in the editing buffer so that | |
20904 | it is possible to type most @value{GDBN} commands without interaction | |
46ba6afa BW |
20905 | with the TUI SingleKey mode. Once the command is entered the TUI |
20906 | SingleKey mode is restored. The only way to permanently leave | |
7f9087cb | 20907 | this mode is by typing @kbd{q} or @kbd{C-x s}. |
7cf36c78 SC |
20908 | |
20909 | ||
8e04817f | 20910 | @node TUI Commands |
db2e3e2e | 20911 | @section TUI-specific Commands |
8e04817f AC |
20912 | @cindex TUI commands |
20913 | ||
20914 | The TUI has specific commands to control the text windows. | |
46ba6afa BW |
20915 | These commands are always available, even when @value{GDBN} is not in |
20916 | the TUI mode. When @value{GDBN} is in the standard mode, most | |
20917 | of these commands will automatically switch to the TUI mode. | |
c906108c SS |
20918 | |
20919 | @table @code | |
3d757584 SC |
20920 | @item info win |
20921 | @kindex info win | |
20922 | List and give the size of all displayed windows. | |
20923 | ||
8e04817f | 20924 | @item layout next |
4644b6e3 | 20925 | @kindex layout |
8e04817f | 20926 | Display the next layout. |
2df3850c | 20927 | |
8e04817f | 20928 | @item layout prev |
8e04817f | 20929 | Display the previous layout. |
c906108c | 20930 | |
8e04817f | 20931 | @item layout src |
8e04817f | 20932 | Display the source window only. |
c906108c | 20933 | |
8e04817f | 20934 | @item layout asm |
8e04817f | 20935 | Display the assembly window only. |
c906108c | 20936 | |
8e04817f | 20937 | @item layout split |
8e04817f | 20938 | Display the source and assembly window. |
c906108c | 20939 | |
8e04817f | 20940 | @item layout regs |
8e04817f AC |
20941 | Display the register window together with the source or assembly window. |
20942 | ||
46ba6afa | 20943 | @item focus next |
8e04817f | 20944 | @kindex focus |
46ba6afa BW |
20945 | Make the next window active for scrolling. |
20946 | ||
20947 | @item focus prev | |
20948 | Make the previous window active for scrolling. | |
20949 | ||
20950 | @item focus src | |
20951 | Make the source window active for scrolling. | |
20952 | ||
20953 | @item focus asm | |
20954 | Make the assembly window active for scrolling. | |
20955 | ||
20956 | @item focus regs | |
20957 | Make the register window active for scrolling. | |
20958 | ||
20959 | @item focus cmd | |
20960 | Make the command window active for scrolling. | |
c906108c | 20961 | |
8e04817f AC |
20962 | @item refresh |
20963 | @kindex refresh | |
7f9087cb | 20964 | Refresh the screen. This is similar to typing @kbd{C-L}. |
c906108c | 20965 | |
6a1b180d SC |
20966 | @item tui reg float |
20967 | @kindex tui reg | |
20968 | Show the floating point registers in the register window. | |
20969 | ||
20970 | @item tui reg general | |
20971 | Show the general registers in the register window. | |
20972 | ||
20973 | @item tui reg next | |
20974 | Show the next register group. The list of register groups as well as | |
20975 | their order is target specific. The predefined register groups are the | |
20976 | following: @code{general}, @code{float}, @code{system}, @code{vector}, | |
20977 | @code{all}, @code{save}, @code{restore}. | |
20978 | ||
20979 | @item tui reg system | |
20980 | Show the system registers in the register window. | |
20981 | ||
8e04817f AC |
20982 | @item update |
20983 | @kindex update | |
20984 | Update the source window and the current execution point. | |
c906108c | 20985 | |
8e04817f AC |
20986 | @item winheight @var{name} +@var{count} |
20987 | @itemx winheight @var{name} -@var{count} | |
20988 | @kindex winheight | |
20989 | Change the height of the window @var{name} by @var{count} | |
20990 | lines. Positive counts increase the height, while negative counts | |
20991 | decrease it. | |
2df3850c | 20992 | |
46ba6afa BW |
20993 | @item tabset @var{nchars} |
20994 | @kindex tabset | |
c45da7e6 | 20995 | Set the width of tab stops to be @var{nchars} characters. |
c906108c SS |
20996 | @end table |
20997 | ||
8e04817f | 20998 | @node TUI Configuration |
79a6e687 | 20999 | @section TUI Configuration Variables |
8e04817f | 21000 | @cindex TUI configuration variables |
c906108c | 21001 | |
46ba6afa | 21002 | Several configuration variables control the appearance of TUI windows. |
c906108c | 21003 | |
8e04817f AC |
21004 | @table @code |
21005 | @item set tui border-kind @var{kind} | |
21006 | @kindex set tui border-kind | |
21007 | Select the border appearance for the source, assembly and register windows. | |
21008 | The possible values are the following: | |
21009 | @table @code | |
21010 | @item space | |
21011 | Use a space character to draw the border. | |
c906108c | 21012 | |
8e04817f | 21013 | @item ascii |
46ba6afa | 21014 | Use @sc{ascii} characters @samp{+}, @samp{-} and @samp{|} to draw the border. |
c906108c | 21015 | |
8e04817f AC |
21016 | @item acs |
21017 | Use the Alternate Character Set to draw the border. The border is | |
21018 | drawn using character line graphics if the terminal supports them. | |
8e04817f | 21019 | @end table |
c78b4128 | 21020 | |
8e04817f AC |
21021 | @item set tui border-mode @var{mode} |
21022 | @kindex set tui border-mode | |
46ba6afa BW |
21023 | @itemx set tui active-border-mode @var{mode} |
21024 | @kindex set tui active-border-mode | |
21025 | Select the display attributes for the borders of the inactive windows | |
21026 | or the active window. The @var{mode} can be one of the following: | |
8e04817f AC |
21027 | @table @code |
21028 | @item normal | |
21029 | Use normal attributes to display the border. | |
c906108c | 21030 | |
8e04817f AC |
21031 | @item standout |
21032 | Use standout mode. | |
c906108c | 21033 | |
8e04817f AC |
21034 | @item reverse |
21035 | Use reverse video mode. | |
c906108c | 21036 | |
8e04817f AC |
21037 | @item half |
21038 | Use half bright mode. | |
c906108c | 21039 | |
8e04817f AC |
21040 | @item half-standout |
21041 | Use half bright and standout mode. | |
c906108c | 21042 | |
8e04817f AC |
21043 | @item bold |
21044 | Use extra bright or bold mode. | |
c78b4128 | 21045 | |
8e04817f AC |
21046 | @item bold-standout |
21047 | Use extra bright or bold and standout mode. | |
8e04817f | 21048 | @end table |
8e04817f | 21049 | @end table |
c78b4128 | 21050 | |
8e04817f AC |
21051 | @node Emacs |
21052 | @chapter Using @value{GDBN} under @sc{gnu} Emacs | |
c78b4128 | 21053 | |
8e04817f AC |
21054 | @cindex Emacs |
21055 | @cindex @sc{gnu} Emacs | |
21056 | A special interface allows you to use @sc{gnu} Emacs to view (and | |
21057 | edit) the source files for the program you are debugging with | |
21058 | @value{GDBN}. | |
c906108c | 21059 | |
8e04817f AC |
21060 | To use this interface, use the command @kbd{M-x gdb} in Emacs. Give the |
21061 | executable file you want to debug as an argument. This command starts | |
21062 | @value{GDBN} as a subprocess of Emacs, with input and output through a newly | |
21063 | created Emacs buffer. | |
21064 | @c (Do not use the @code{-tui} option to run @value{GDBN} from Emacs.) | |
c906108c | 21065 | |
5e252a2e | 21066 | Running @value{GDBN} under Emacs can be just like running @value{GDBN} normally except for two |
8e04817f | 21067 | things: |
c906108c | 21068 | |
8e04817f AC |
21069 | @itemize @bullet |
21070 | @item | |
5e252a2e NR |
21071 | All ``terminal'' input and output goes through an Emacs buffer, called |
21072 | the GUD buffer. | |
c906108c | 21073 | |
8e04817f AC |
21074 | This applies both to @value{GDBN} commands and their output, and to the input |
21075 | and output done by the program you are debugging. | |
bf0184be | 21076 | |
8e04817f AC |
21077 | This is useful because it means that you can copy the text of previous |
21078 | commands and input them again; you can even use parts of the output | |
21079 | in this way. | |
bf0184be | 21080 | |
8e04817f AC |
21081 | All the facilities of Emacs' Shell mode are available for interacting |
21082 | with your program. In particular, you can send signals the usual | |
21083 | way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a | |
21084 | stop. | |
bf0184be ND |
21085 | |
21086 | @item | |
8e04817f | 21087 | @value{GDBN} displays source code through Emacs. |
bf0184be | 21088 | |
8e04817f AC |
21089 | Each time @value{GDBN} displays a stack frame, Emacs automatically finds the |
21090 | source file for that frame and puts an arrow (@samp{=>}) at the | |
21091 | left margin of the current line. Emacs uses a separate buffer for | |
21092 | source display, and splits the screen to show both your @value{GDBN} session | |
21093 | and the source. | |
bf0184be | 21094 | |
8e04817f AC |
21095 | Explicit @value{GDBN} @code{list} or search commands still produce output as |
21096 | usual, but you probably have no reason to use them from Emacs. | |
5e252a2e NR |
21097 | @end itemize |
21098 | ||
21099 | We call this @dfn{text command mode}. Emacs 22.1, and later, also uses | |
21100 | a graphical mode, enabled by default, which provides further buffers | |
21101 | that can control the execution and describe the state of your program. | |
21102 | @xref{GDB Graphical Interface,,, Emacs, The @sc{gnu} Emacs Manual}. | |
c906108c | 21103 | |
64fabec2 AC |
21104 | If you specify an absolute file name when prompted for the @kbd{M-x |
21105 | gdb} argument, then Emacs sets your current working directory to where | |
21106 | your program resides. If you only specify the file name, then Emacs | |
21107 | sets your current working directory to to the directory associated | |
21108 | with the previous buffer. In this case, @value{GDBN} may find your | |
21109 | program by searching your environment's @code{PATH} variable, but on | |
21110 | some operating systems it might not find the source. So, although the | |
21111 | @value{GDBN} input and output session proceeds normally, the auxiliary | |
21112 | buffer does not display the current source and line of execution. | |
21113 | ||
21114 | The initial working directory of @value{GDBN} is printed on the top | |
5e252a2e NR |
21115 | line of the GUD buffer and this serves as a default for the commands |
21116 | that specify files for @value{GDBN} to operate on. @xref{Files, | |
21117 | ,Commands to Specify Files}. | |
64fabec2 AC |
21118 | |
21119 | By default, @kbd{M-x gdb} calls the program called @file{gdb}. If you | |
21120 | need to call @value{GDBN} by a different name (for example, if you | |
21121 | keep several configurations around, with different names) you can | |
21122 | customize the Emacs variable @code{gud-gdb-command-name} to run the | |
21123 | one you want. | |
8e04817f | 21124 | |
5e252a2e | 21125 | In the GUD buffer, you can use these special Emacs commands in |
8e04817f | 21126 | addition to the standard Shell mode commands: |
c906108c | 21127 | |
8e04817f AC |
21128 | @table @kbd |
21129 | @item C-h m | |
5e252a2e | 21130 | Describe the features of Emacs' GUD Mode. |
c906108c | 21131 | |
64fabec2 | 21132 | @item C-c C-s |
8e04817f AC |
21133 | Execute to another source line, like the @value{GDBN} @code{step} command; also |
21134 | update the display window to show the current file and location. | |
c906108c | 21135 | |
64fabec2 | 21136 | @item C-c C-n |
8e04817f AC |
21137 | Execute to next source line in this function, skipping all function |
21138 | calls, like the @value{GDBN} @code{next} command. Then update the display window | |
21139 | to show the current file and location. | |
c906108c | 21140 | |
64fabec2 | 21141 | @item C-c C-i |
8e04817f AC |
21142 | Execute one instruction, like the @value{GDBN} @code{stepi} command; update |
21143 | display window accordingly. | |
c906108c | 21144 | |
8e04817f AC |
21145 | @item C-c C-f |
21146 | Execute until exit from the selected stack frame, like the @value{GDBN} | |
21147 | @code{finish} command. | |
c906108c | 21148 | |
64fabec2 | 21149 | @item C-c C-r |
8e04817f AC |
21150 | Continue execution of your program, like the @value{GDBN} @code{continue} |
21151 | command. | |
b433d00b | 21152 | |
64fabec2 | 21153 | @item C-c < |
8e04817f AC |
21154 | Go up the number of frames indicated by the numeric argument |
21155 | (@pxref{Arguments, , Numeric Arguments, Emacs, The @sc{gnu} Emacs Manual}), | |
21156 | like the @value{GDBN} @code{up} command. | |
b433d00b | 21157 | |
64fabec2 | 21158 | @item C-c > |
8e04817f AC |
21159 | Go down the number of frames indicated by the numeric argument, like the |
21160 | @value{GDBN} @code{down} command. | |
8e04817f | 21161 | @end table |
c906108c | 21162 | |
7f9087cb | 21163 | In any source file, the Emacs command @kbd{C-x @key{SPC}} (@code{gud-break}) |
8e04817f | 21164 | tells @value{GDBN} to set a breakpoint on the source line point is on. |
c906108c | 21165 | |
5e252a2e NR |
21166 | In text command mode, if you type @kbd{M-x speedbar}, Emacs displays a |
21167 | separate frame which shows a backtrace when the GUD buffer is current. | |
21168 | Move point to any frame in the stack and type @key{RET} to make it | |
21169 | become the current frame and display the associated source in the | |
21170 | source buffer. Alternatively, click @kbd{Mouse-2} to make the | |
21171 | selected frame become the current one. In graphical mode, the | |
21172 | speedbar displays watch expressions. | |
64fabec2 | 21173 | |
8e04817f AC |
21174 | If you accidentally delete the source-display buffer, an easy way to get |
21175 | it back is to type the command @code{f} in the @value{GDBN} buffer, to | |
21176 | request a frame display; when you run under Emacs, this recreates | |
21177 | the source buffer if necessary to show you the context of the current | |
21178 | frame. | |
c906108c | 21179 | |
8e04817f AC |
21180 | The source files displayed in Emacs are in ordinary Emacs buffers |
21181 | which are visiting the source files in the usual way. You can edit | |
21182 | the files with these buffers if you wish; but keep in mind that @value{GDBN} | |
21183 | communicates with Emacs in terms of line numbers. If you add or | |
21184 | delete lines from the text, the line numbers that @value{GDBN} knows cease | |
21185 | to correspond properly with the code. | |
b383017d | 21186 | |
5e252a2e NR |
21187 | A more detailed description of Emacs' interaction with @value{GDBN} is |
21188 | given in the Emacs manual (@pxref{Debuggers,,, Emacs, The @sc{gnu} | |
21189 | Emacs Manual}). | |
c906108c | 21190 | |
8e04817f AC |
21191 | @c The following dropped because Epoch is nonstandard. Reactivate |
21192 | @c if/when v19 does something similar. ---doc@cygnus.com 19dec1990 | |
21193 | @ignore | |
21194 | @kindex Emacs Epoch environment | |
21195 | @kindex Epoch | |
21196 | @kindex inspect | |
c906108c | 21197 | |
8e04817f AC |
21198 | Version 18 of @sc{gnu} Emacs has a built-in window system |
21199 | called the @code{epoch} | |
21200 | environment. Users of this environment can use a new command, | |
21201 | @code{inspect} which performs identically to @code{print} except that | |
21202 | each value is printed in its own window. | |
21203 | @end ignore | |
c906108c | 21204 | |
922fbb7b AC |
21205 | |
21206 | @node GDB/MI | |
21207 | @chapter The @sc{gdb/mi} Interface | |
21208 | ||
21209 | @unnumberedsec Function and Purpose | |
21210 | ||
21211 | @cindex @sc{gdb/mi}, its purpose | |
6b5e8c01 NR |
21212 | @sc{gdb/mi} is a line based machine oriented text interface to |
21213 | @value{GDBN} and is activated by specifying using the | |
21214 | @option{--interpreter} command line option (@pxref{Mode Options}). It | |
21215 | is specifically intended to support the development of systems which | |
21216 | use the debugger as just one small component of a larger system. | |
922fbb7b AC |
21217 | |
21218 | This chapter is a specification of the @sc{gdb/mi} interface. It is written | |
21219 | in the form of a reference manual. | |
21220 | ||
21221 | Note that @sc{gdb/mi} is still under construction, so some of the | |
af6eff6f NR |
21222 | features described below are incomplete and subject to change |
21223 | (@pxref{GDB/MI Development and Front Ends, , @sc{gdb/mi} Development and Front Ends}). | |
922fbb7b AC |
21224 | |
21225 | @unnumberedsec Notation and Terminology | |
21226 | ||
21227 | @cindex notational conventions, for @sc{gdb/mi} | |
21228 | This chapter uses the following notation: | |
21229 | ||
21230 | @itemize @bullet | |
21231 | @item | |
21232 | @code{|} separates two alternatives. | |
21233 | ||
21234 | @item | |
21235 | @code{[ @var{something} ]} indicates that @var{something} is optional: | |
21236 | it may or may not be given. | |
21237 | ||
21238 | @item | |
21239 | @code{( @var{group} )*} means that @var{group} inside the parentheses | |
21240 | may repeat zero or more times. | |
21241 | ||
21242 | @item | |
21243 | @code{( @var{group} )+} means that @var{group} inside the parentheses | |
21244 | may repeat one or more times. | |
21245 | ||
21246 | @item | |
21247 | @code{"@var{string}"} means a literal @var{string}. | |
21248 | @end itemize | |
21249 | ||
21250 | @ignore | |
21251 | @heading Dependencies | |
21252 | @end ignore | |
21253 | ||
922fbb7b | 21254 | @menu |
c3b108f7 | 21255 | * GDB/MI General Design:: |
922fbb7b AC |
21256 | * GDB/MI Command Syntax:: |
21257 | * GDB/MI Compatibility with CLI:: | |
af6eff6f | 21258 | * GDB/MI Development and Front Ends:: |
922fbb7b | 21259 | * GDB/MI Output Records:: |
ef21caaf | 21260 | * GDB/MI Simple Examples:: |
922fbb7b | 21261 | * GDB/MI Command Description Format:: |
ef21caaf | 21262 | * GDB/MI Breakpoint Commands:: |
a2c02241 NR |
21263 | * GDB/MI Program Context:: |
21264 | * GDB/MI Thread Commands:: | |
21265 | * GDB/MI Program Execution:: | |
21266 | * GDB/MI Stack Manipulation:: | |
21267 | * GDB/MI Variable Objects:: | |
922fbb7b | 21268 | * GDB/MI Data Manipulation:: |
a2c02241 NR |
21269 | * GDB/MI Tracepoint Commands:: |
21270 | * GDB/MI Symbol Query:: | |
351ff01a | 21271 | * GDB/MI File Commands:: |
922fbb7b AC |
21272 | @ignore |
21273 | * GDB/MI Kod Commands:: | |
21274 | * GDB/MI Memory Overlay Commands:: | |
21275 | * GDB/MI Signal Handling Commands:: | |
21276 | @end ignore | |
922fbb7b | 21277 | * GDB/MI Target Manipulation:: |
a6b151f1 | 21278 | * GDB/MI File Transfer Commands:: |
ef21caaf | 21279 | * GDB/MI Miscellaneous Commands:: |
922fbb7b AC |
21280 | @end menu |
21281 | ||
c3b108f7 VP |
21282 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21283 | @node GDB/MI General Design | |
21284 | @section @sc{gdb/mi} General Design | |
21285 | @cindex GDB/MI General Design | |
21286 | ||
21287 | Interaction of a @sc{GDB/MI} frontend with @value{GDBN} involves three | |
21288 | parts---commands sent to @value{GDBN}, responses to those commands | |
21289 | and notifications. Each command results in exactly one response, | |
21290 | indicating either successful completion of the command, or an error. | |
21291 | For the commands that do not resume the target, the response contains the | |
21292 | requested information. For the commands that resume the target, the | |
21293 | response only indicates whether the target was successfully resumed. | |
21294 | Notifications is the mechanism for reporting changes in the state of the | |
21295 | target, or in @value{GDBN} state, that cannot conveniently be associated with | |
21296 | a command and reported as part of that command response. | |
21297 | ||
21298 | The important examples of notifications are: | |
21299 | @itemize @bullet | |
21300 | ||
21301 | @item | |
21302 | Exec notifications. These are used to report changes in | |
21303 | target state---when a target is resumed, or stopped. It would not | |
21304 | be feasible to include this information in response of resuming | |
21305 | commands, because one resume commands can result in multiple events in | |
21306 | different threads. Also, quite some time may pass before any event | |
21307 | happens in the target, while a frontend needs to know whether the resuming | |
21308 | command itself was successfully executed. | |
21309 | ||
21310 | @item | |
21311 | Console output, and status notifications. Console output | |
21312 | notifications are used to report output of CLI commands, as well as | |
21313 | diagnostics for other commands. Status notifications are used to | |
21314 | report the progress of a long-running operation. Naturally, including | |
21315 | this information in command response would mean no output is produced | |
21316 | until the command is finished, which is undesirable. | |
21317 | ||
21318 | @item | |
21319 | General notifications. Commands may have various side effects on | |
21320 | the @value{GDBN} or target state beyond their official purpose. For example, | |
21321 | a command may change the selected thread. Although such changes can | |
21322 | be included in command response, using notification allows for more | |
21323 | orthogonal frontend design. | |
21324 | ||
21325 | @end itemize | |
21326 | ||
21327 | There's no guarantee that whenever an MI command reports an error, | |
21328 | @value{GDBN} or the target are in any specific state, and especially, | |
21329 | the state is not reverted to the state before the MI command was | |
21330 | processed. Therefore, whenever an MI command results in an error, | |
21331 | we recommend that the frontend refreshes all the information shown in | |
21332 | the user interface. | |
21333 | ||
508094de NR |
21334 | |
21335 | @menu | |
21336 | * Context management:: | |
21337 | * Asynchronous and non-stop modes:: | |
21338 | * Thread groups:: | |
21339 | @end menu | |
21340 | ||
21341 | @node Context management | |
c3b108f7 VP |
21342 | @subsection Context management |
21343 | ||
21344 | In most cases when @value{GDBN} accesses the target, this access is | |
21345 | done in context of a specific thread and frame (@pxref{Frames}). | |
21346 | Often, even when accessing global data, the target requires that a thread | |
21347 | be specified. The CLI interface maintains the selected thread and frame, | |
21348 | and supplies them to target on each command. This is convenient, | |
21349 | because a command line user would not want to specify that information | |
21350 | explicitly on each command, and because user interacts with | |
21351 | @value{GDBN} via a single terminal, so no confusion is possible as | |
21352 | to what thread and frame are the current ones. | |
21353 | ||
21354 | In the case of MI, the concept of selected thread and frame is less | |
21355 | useful. First, a frontend can easily remember this information | |
21356 | itself. Second, a graphical frontend can have more than one window, | |
21357 | each one used for debugging a different thread, and the frontend might | |
21358 | want to access additional threads for internal purposes. This | |
21359 | increases the risk that by relying on implicitly selected thread, the | |
21360 | frontend may be operating on a wrong one. Therefore, each MI command | |
21361 | should explicitly specify which thread and frame to operate on. To | |
21362 | make it possible, each MI command accepts the @samp{--thread} and | |
21363 | @samp{--frame} options, the value to each is @value{GDBN} identifier | |
21364 | for thread and frame to operate on. | |
21365 | ||
21366 | Usually, each top-level window in a frontend allows the user to select | |
21367 | a thread and a frame, and remembers the user selection for further | |
21368 | operations. However, in some cases @value{GDBN} may suggest that the | |
21369 | current thread be changed. For example, when stopping on a breakpoint | |
21370 | it is reasonable to switch to the thread where breakpoint is hit. For | |
21371 | another example, if the user issues the CLI @samp{thread} command via | |
21372 | the frontend, it is desirable to change the frontend's selected thread to the | |
21373 | one specified by user. @value{GDBN} communicates the suggestion to | |
21374 | change current thread using the @samp{=thread-selected} notification. | |
21375 | No such notification is available for the selected frame at the moment. | |
21376 | ||
21377 | Note that historically, MI shares the selected thread with CLI, so | |
21378 | frontends used the @code{-thread-select} to execute commands in the | |
21379 | right context. However, getting this to work right is cumbersome. The | |
21380 | simplest way is for frontend to emit @code{-thread-select} command | |
21381 | before every command. This doubles the number of commands that need | |
21382 | to be sent. The alternative approach is to suppress @code{-thread-select} | |
21383 | if the selected thread in @value{GDBN} is supposed to be identical to the | |
21384 | thread the frontend wants to operate on. However, getting this | |
21385 | optimization right can be tricky. In particular, if the frontend | |
21386 | sends several commands to @value{GDBN}, and one of the commands changes the | |
21387 | selected thread, then the behaviour of subsequent commands will | |
21388 | change. So, a frontend should either wait for response from such | |
21389 | problematic commands, or explicitly add @code{-thread-select} for | |
21390 | all subsequent commands. No frontend is known to do this exactly | |
21391 | right, so it is suggested to just always pass the @samp{--thread} and | |
21392 | @samp{--frame} options. | |
21393 | ||
508094de | 21394 | @node Asynchronous and non-stop modes |
c3b108f7 VP |
21395 | @subsection Asynchronous command execution and non-stop mode |
21396 | ||
21397 | On some targets, @value{GDBN} is capable of processing MI commands | |
21398 | even while the target is running. This is called @dfn{asynchronous | |
21399 | command execution} (@pxref{Background Execution}). The frontend may | |
21400 | specify a preferrence for asynchronous execution using the | |
21401 | @code{-gdb-set target-async 1} command, which should be emitted before | |
21402 | either running the executable or attaching to the target. After the | |
21403 | frontend has started the executable or attached to the target, it can | |
21404 | find if asynchronous execution is enabled using the | |
21405 | @code{-list-target-features} command. | |
21406 | ||
21407 | Even if @value{GDBN} can accept a command while target is running, | |
21408 | many commands that access the target do not work when the target is | |
21409 | running. Therefore, asynchronous command execution is most useful | |
21410 | when combined with non-stop mode (@pxref{Non-Stop Mode}). Then, | |
21411 | it is possible to examine the state of one thread, while other threads | |
21412 | are running. | |
21413 | ||
21414 | When a given thread is running, MI commands that try to access the | |
21415 | target in the context of that thread may not work, or may work only on | |
21416 | some targets. In particular, commands that try to operate on thread's | |
21417 | stack will not work, on any target. Commands that read memory, or | |
21418 | modify breakpoints, may work or not work, depending on the target. Note | |
21419 | that even commands that operate on global state, such as @code{print}, | |
21420 | @code{set}, and breakpoint commands, still access the target in the | |
21421 | context of a specific thread, so frontend should try to find a | |
21422 | stopped thread and perform the operation on that thread (using the | |
21423 | @samp{--thread} option). | |
21424 | ||
21425 | Which commands will work in the context of a running thread is | |
21426 | highly target dependent. However, the two commands | |
21427 | @code{-exec-interrupt}, to stop a thread, and @code{-thread-info}, | |
21428 | to find the state of a thread, will always work. | |
21429 | ||
508094de | 21430 | @node Thread groups |
c3b108f7 VP |
21431 | @subsection Thread groups |
21432 | @value{GDBN} may be used to debug several processes at the same time. | |
21433 | On some platfroms, @value{GDBN} may support debugging of several | |
21434 | hardware systems, each one having several cores with several different | |
21435 | processes running on each core. This section describes the MI | |
21436 | mechanism to support such debugging scenarios. | |
21437 | ||
21438 | The key observation is that regardless of the structure of the | |
21439 | target, MI can have a global list of threads, because most commands that | |
21440 | accept the @samp{--thread} option do not need to know what process that | |
21441 | thread belongs to. Therefore, it is not necessary to introduce | |
21442 | neither additional @samp{--process} option, nor an notion of the | |
21443 | current process in the MI interface. The only strictly new feature | |
21444 | that is required is the ability to find how the threads are grouped | |
21445 | into processes. | |
21446 | ||
21447 | To allow the user to discover such grouping, and to support arbitrary | |
21448 | hierarchy of machines/cores/processes, MI introduces the concept of a | |
21449 | @dfn{thread group}. Thread group is a collection of threads and other | |
21450 | thread groups. A thread group always has a string identifier, a type, | |
21451 | and may have additional attributes specific to the type. A new | |
21452 | command, @code{-list-thread-groups}, returns the list of top-level | |
21453 | thread groups, which correspond to processes that @value{GDBN} is | |
21454 | debugging at the moment. By passing an identifier of a thread group | |
21455 | to the @code{-list-thread-groups} command, it is possible to obtain | |
21456 | the members of specific thread group. | |
21457 | ||
21458 | To allow the user to easily discover processes, and other objects, he | |
21459 | wishes to debug, a concept of @dfn{available thread group} is | |
21460 | introduced. Available thread group is an thread group that | |
21461 | @value{GDBN} is not debugging, but that can be attached to, using the | |
21462 | @code{-target-attach} command. The list of available top-level thread | |
21463 | groups can be obtained using @samp{-list-thread-groups --available}. | |
21464 | In general, the content of a thread group may be only retrieved only | |
21465 | after attaching to that thread group. | |
21466 | ||
922fbb7b AC |
21467 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21468 | @node GDB/MI Command Syntax | |
21469 | @section @sc{gdb/mi} Command Syntax | |
21470 | ||
21471 | @menu | |
21472 | * GDB/MI Input Syntax:: | |
21473 | * GDB/MI Output Syntax:: | |
922fbb7b AC |
21474 | @end menu |
21475 | ||
21476 | @node GDB/MI Input Syntax | |
21477 | @subsection @sc{gdb/mi} Input Syntax | |
21478 | ||
21479 | @cindex input syntax for @sc{gdb/mi} | |
21480 | @cindex @sc{gdb/mi}, input syntax | |
21481 | @table @code | |
21482 | @item @var{command} @expansion{} | |
21483 | @code{@var{cli-command} | @var{mi-command}} | |
21484 | ||
21485 | @item @var{cli-command} @expansion{} | |
21486 | @code{[ @var{token} ] @var{cli-command} @var{nl}}, where | |
21487 | @var{cli-command} is any existing @value{GDBN} CLI command. | |
21488 | ||
21489 | @item @var{mi-command} @expansion{} | |
21490 | @code{[ @var{token} ] "-" @var{operation} ( " " @var{option} )* | |
21491 | @code{[} " --" @code{]} ( " " @var{parameter} )* @var{nl}} | |
21492 | ||
21493 | @item @var{token} @expansion{} | |
21494 | "any sequence of digits" | |
21495 | ||
21496 | @item @var{option} @expansion{} | |
21497 | @code{"-" @var{parameter} [ " " @var{parameter} ]} | |
21498 | ||
21499 | @item @var{parameter} @expansion{} | |
21500 | @code{@var{non-blank-sequence} | @var{c-string}} | |
21501 | ||
21502 | @item @var{operation} @expansion{} | |
21503 | @emph{any of the operations described in this chapter} | |
21504 | ||
21505 | @item @var{non-blank-sequence} @expansion{} | |
21506 | @emph{anything, provided it doesn't contain special characters such as | |
21507 | "-", @var{nl}, """ and of course " "} | |
21508 | ||
21509 | @item @var{c-string} @expansion{} | |
21510 | @code{""" @var{seven-bit-iso-c-string-content} """} | |
21511 | ||
21512 | @item @var{nl} @expansion{} | |
21513 | @code{CR | CR-LF} | |
21514 | @end table | |
21515 | ||
21516 | @noindent | |
21517 | Notes: | |
21518 | ||
21519 | @itemize @bullet | |
21520 | @item | |
21521 | The CLI commands are still handled by the @sc{mi} interpreter; their | |
21522 | output is described below. | |
21523 | ||
21524 | @item | |
21525 | The @code{@var{token}}, when present, is passed back when the command | |
21526 | finishes. | |
21527 | ||
21528 | @item | |
21529 | Some @sc{mi} commands accept optional arguments as part of the parameter | |
21530 | list. Each option is identified by a leading @samp{-} (dash) and may be | |
21531 | followed by an optional argument parameter. Options occur first in the | |
21532 | parameter list and can be delimited from normal parameters using | |
21533 | @samp{--} (this is useful when some parameters begin with a dash). | |
21534 | @end itemize | |
21535 | ||
21536 | Pragmatics: | |
21537 | ||
21538 | @itemize @bullet | |
21539 | @item | |
21540 | We want easy access to the existing CLI syntax (for debugging). | |
21541 | ||
21542 | @item | |
21543 | We want it to be easy to spot a @sc{mi} operation. | |
21544 | @end itemize | |
21545 | ||
21546 | @node GDB/MI Output Syntax | |
21547 | @subsection @sc{gdb/mi} Output Syntax | |
21548 | ||
21549 | @cindex output syntax of @sc{gdb/mi} | |
21550 | @cindex @sc{gdb/mi}, output syntax | |
21551 | The output from @sc{gdb/mi} consists of zero or more out-of-band records | |
21552 | followed, optionally, by a single result record. This result record | |
21553 | is for the most recent command. The sequence of output records is | |
594fe323 | 21554 | terminated by @samp{(gdb)}. |
922fbb7b AC |
21555 | |
21556 | If an input command was prefixed with a @code{@var{token}} then the | |
21557 | corresponding output for that command will also be prefixed by that same | |
21558 | @var{token}. | |
21559 | ||
21560 | @table @code | |
21561 | @item @var{output} @expansion{} | |
594fe323 | 21562 | @code{( @var{out-of-band-record} )* [ @var{result-record} ] "(gdb)" @var{nl}} |
922fbb7b AC |
21563 | |
21564 | @item @var{result-record} @expansion{} | |
21565 | @code{ [ @var{token} ] "^" @var{result-class} ( "," @var{result} )* @var{nl}} | |
21566 | ||
21567 | @item @var{out-of-band-record} @expansion{} | |
21568 | @code{@var{async-record} | @var{stream-record}} | |
21569 | ||
21570 | @item @var{async-record} @expansion{} | |
21571 | @code{@var{exec-async-output} | @var{status-async-output} | @var{notify-async-output}} | |
21572 | ||
21573 | @item @var{exec-async-output} @expansion{} | |
21574 | @code{[ @var{token} ] "*" @var{async-output}} | |
21575 | ||
21576 | @item @var{status-async-output} @expansion{} | |
21577 | @code{[ @var{token} ] "+" @var{async-output}} | |
21578 | ||
21579 | @item @var{notify-async-output} @expansion{} | |
21580 | @code{[ @var{token} ] "=" @var{async-output}} | |
21581 | ||
21582 | @item @var{async-output} @expansion{} | |
21583 | @code{@var{async-class} ( "," @var{result} )* @var{nl}} | |
21584 | ||
21585 | @item @var{result-class} @expansion{} | |
21586 | @code{"done" | "running" | "connected" | "error" | "exit"} | |
21587 | ||
21588 | @item @var{async-class} @expansion{} | |
21589 | @code{"stopped" | @var{others}} (where @var{others} will be added | |
21590 | depending on the needs---this is still in development). | |
21591 | ||
21592 | @item @var{result} @expansion{} | |
21593 | @code{ @var{variable} "=" @var{value}} | |
21594 | ||
21595 | @item @var{variable} @expansion{} | |
21596 | @code{ @var{string} } | |
21597 | ||
21598 | @item @var{value} @expansion{} | |
21599 | @code{ @var{const} | @var{tuple} | @var{list} } | |
21600 | ||
21601 | @item @var{const} @expansion{} | |
21602 | @code{@var{c-string}} | |
21603 | ||
21604 | @item @var{tuple} @expansion{} | |
21605 | @code{ "@{@}" | "@{" @var{result} ( "," @var{result} )* "@}" } | |
21606 | ||
21607 | @item @var{list} @expansion{} | |
21608 | @code{ "[]" | "[" @var{value} ( "," @var{value} )* "]" | "[" | |
21609 | @var{result} ( "," @var{result} )* "]" } | |
21610 | ||
21611 | @item @var{stream-record} @expansion{} | |
21612 | @code{@var{console-stream-output} | @var{target-stream-output} | @var{log-stream-output}} | |
21613 | ||
21614 | @item @var{console-stream-output} @expansion{} | |
21615 | @code{"~" @var{c-string}} | |
21616 | ||
21617 | @item @var{target-stream-output} @expansion{} | |
21618 | @code{"@@" @var{c-string}} | |
21619 | ||
21620 | @item @var{log-stream-output} @expansion{} | |
21621 | @code{"&" @var{c-string}} | |
21622 | ||
21623 | @item @var{nl} @expansion{} | |
21624 | @code{CR | CR-LF} | |
21625 | ||
21626 | @item @var{token} @expansion{} | |
21627 | @emph{any sequence of digits}. | |
21628 | @end table | |
21629 | ||
21630 | @noindent | |
21631 | Notes: | |
21632 | ||
21633 | @itemize @bullet | |
21634 | @item | |
21635 | All output sequences end in a single line containing a period. | |
21636 | ||
21637 | @item | |
721c02de VP |
21638 | The @code{@var{token}} is from the corresponding request. Note that |
21639 | for all async output, while the token is allowed by the grammar and | |
21640 | may be output by future versions of @value{GDBN} for select async | |
21641 | output messages, it is generally omitted. Frontends should treat | |
21642 | all async output as reporting general changes in the state of the | |
21643 | target and there should be no need to associate async output to any | |
21644 | prior command. | |
922fbb7b AC |
21645 | |
21646 | @item | |
21647 | @cindex status output in @sc{gdb/mi} | |
21648 | @var{status-async-output} contains on-going status information about the | |
21649 | progress of a slow operation. It can be discarded. All status output is | |
21650 | prefixed by @samp{+}. | |
21651 | ||
21652 | @item | |
21653 | @cindex async output in @sc{gdb/mi} | |
21654 | @var{exec-async-output} contains asynchronous state change on the target | |
21655 | (stopped, started, disappeared). All async output is prefixed by | |
21656 | @samp{*}. | |
21657 | ||
21658 | @item | |
21659 | @cindex notify output in @sc{gdb/mi} | |
21660 | @var{notify-async-output} contains supplementary information that the | |
21661 | client should handle (e.g., a new breakpoint information). All notify | |
21662 | output is prefixed by @samp{=}. | |
21663 | ||
21664 | @item | |
21665 | @cindex console output in @sc{gdb/mi} | |
21666 | @var{console-stream-output} is output that should be displayed as is in the | |
21667 | console. It is the textual response to a CLI command. All the console | |
21668 | output is prefixed by @samp{~}. | |
21669 | ||
21670 | @item | |
21671 | @cindex target output in @sc{gdb/mi} | |
21672 | @var{target-stream-output} is the output produced by the target program. | |
21673 | All the target output is prefixed by @samp{@@}. | |
21674 | ||
21675 | @item | |
21676 | @cindex log output in @sc{gdb/mi} | |
21677 | @var{log-stream-output} is output text coming from @value{GDBN}'s internals, for | |
21678 | instance messages that should be displayed as part of an error log. All | |
21679 | the log output is prefixed by @samp{&}. | |
21680 | ||
21681 | @item | |
21682 | @cindex list output in @sc{gdb/mi} | |
21683 | New @sc{gdb/mi} commands should only output @var{lists} containing | |
21684 | @var{values}. | |
21685 | ||
21686 | ||
21687 | @end itemize | |
21688 | ||
21689 | @xref{GDB/MI Stream Records, , @sc{gdb/mi} Stream Records}, for more | |
21690 | details about the various output records. | |
21691 | ||
922fbb7b AC |
21692 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21693 | @node GDB/MI Compatibility with CLI | |
21694 | @section @sc{gdb/mi} Compatibility with CLI | |
21695 | ||
21696 | @cindex compatibility, @sc{gdb/mi} and CLI | |
21697 | @cindex @sc{gdb/mi}, compatibility with CLI | |
922fbb7b | 21698 | |
a2c02241 NR |
21699 | For the developers convenience CLI commands can be entered directly, |
21700 | but there may be some unexpected behaviour. For example, commands | |
21701 | that query the user will behave as if the user replied yes, breakpoint | |
21702 | command lists are not executed and some CLI commands, such as | |
21703 | @code{if}, @code{when} and @code{define}, prompt for further input with | |
21704 | @samp{>}, which is not valid MI output. | |
ef21caaf NR |
21705 | |
21706 | This feature may be removed at some stage in the future and it is | |
a2c02241 NR |
21707 | recommended that front ends use the @code{-interpreter-exec} command |
21708 | (@pxref{-interpreter-exec}). | |
922fbb7b | 21709 | |
af6eff6f NR |
21710 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21711 | @node GDB/MI Development and Front Ends | |
21712 | @section @sc{gdb/mi} Development and Front Ends | |
21713 | @cindex @sc{gdb/mi} development | |
21714 | ||
21715 | The application which takes the MI output and presents the state of the | |
21716 | program being debugged to the user is called a @dfn{front end}. | |
21717 | ||
21718 | Although @sc{gdb/mi} is still incomplete, it is currently being used | |
21719 | by a variety of front ends to @value{GDBN}. This makes it difficult | |
21720 | to introduce new functionality without breaking existing usage. This | |
21721 | section tries to minimize the problems by describing how the protocol | |
21722 | might change. | |
21723 | ||
21724 | Some changes in MI need not break a carefully designed front end, and | |
21725 | for these the MI version will remain unchanged. The following is a | |
21726 | list of changes that may occur within one level, so front ends should | |
21727 | parse MI output in a way that can handle them: | |
21728 | ||
21729 | @itemize @bullet | |
21730 | @item | |
21731 | New MI commands may be added. | |
21732 | ||
21733 | @item | |
21734 | New fields may be added to the output of any MI command. | |
21735 | ||
36ece8b3 NR |
21736 | @item |
21737 | The range of values for fields with specified values, e.g., | |
9f708cb2 | 21738 | @code{in_scope} (@pxref{-var-update}) may be extended. |
36ece8b3 | 21739 | |
af6eff6f NR |
21740 | @c The format of field's content e.g type prefix, may change so parse it |
21741 | @c at your own risk. Yes, in general? | |
21742 | ||
21743 | @c The order of fields may change? Shouldn't really matter but it might | |
21744 | @c resolve inconsistencies. | |
21745 | @end itemize | |
21746 | ||
21747 | If the changes are likely to break front ends, the MI version level | |
21748 | will be increased by one. This will allow the front end to parse the | |
21749 | output according to the MI version. Apart from mi0, new versions of | |
21750 | @value{GDBN} will not support old versions of MI and it will be the | |
21751 | responsibility of the front end to work with the new one. | |
21752 | ||
21753 | @c Starting with mi3, add a new command -mi-version that prints the MI | |
21754 | @c version? | |
21755 | ||
21756 | The best way to avoid unexpected changes in MI that might break your front | |
21757 | end is to make your project known to @value{GDBN} developers and | |
7a9a6b69 | 21758 | follow development on @email{gdb@@sourceware.org} and |
fa0f268d | 21759 | @email{gdb-patches@@sourceware.org}. |
af6eff6f NR |
21760 | @cindex mailing lists |
21761 | ||
922fbb7b AC |
21762 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21763 | @node GDB/MI Output Records | |
21764 | @section @sc{gdb/mi} Output Records | |
21765 | ||
21766 | @menu | |
21767 | * GDB/MI Result Records:: | |
21768 | * GDB/MI Stream Records:: | |
82f68b1c | 21769 | * GDB/MI Async Records:: |
c3b108f7 | 21770 | * GDB/MI Frame Information:: |
922fbb7b AC |
21771 | @end menu |
21772 | ||
21773 | @node GDB/MI Result Records | |
21774 | @subsection @sc{gdb/mi} Result Records | |
21775 | ||
21776 | @cindex result records in @sc{gdb/mi} | |
21777 | @cindex @sc{gdb/mi}, result records | |
21778 | In addition to a number of out-of-band notifications, the response to a | |
21779 | @sc{gdb/mi} command includes one of the following result indications: | |
21780 | ||
21781 | @table @code | |
21782 | @findex ^done | |
21783 | @item "^done" [ "," @var{results} ] | |
21784 | The synchronous operation was successful, @code{@var{results}} are the return | |
21785 | values. | |
21786 | ||
21787 | @item "^running" | |
21788 | @findex ^running | |
21789 | @c Is this one correct? Should it be an out-of-band notification? | |
21790 | The asynchronous operation was successfully started. The target is | |
21791 | running. | |
21792 | ||
ef21caaf NR |
21793 | @item "^connected" |
21794 | @findex ^connected | |
3f94c067 | 21795 | @value{GDBN} has connected to a remote target. |
ef21caaf | 21796 | |
922fbb7b AC |
21797 | @item "^error" "," @var{c-string} |
21798 | @findex ^error | |
21799 | The operation failed. The @code{@var{c-string}} contains the corresponding | |
21800 | error message. | |
ef21caaf NR |
21801 | |
21802 | @item "^exit" | |
21803 | @findex ^exit | |
3f94c067 | 21804 | @value{GDBN} has terminated. |
ef21caaf | 21805 | |
922fbb7b AC |
21806 | @end table |
21807 | ||
21808 | @node GDB/MI Stream Records | |
21809 | @subsection @sc{gdb/mi} Stream Records | |
21810 | ||
21811 | @cindex @sc{gdb/mi}, stream records | |
21812 | @cindex stream records in @sc{gdb/mi} | |
21813 | @value{GDBN} internally maintains a number of output streams: the console, the | |
21814 | target, and the log. The output intended for each of these streams is | |
21815 | funneled through the @sc{gdb/mi} interface using @dfn{stream records}. | |
21816 | ||
21817 | Each stream record begins with a unique @dfn{prefix character} which | |
21818 | identifies its stream (@pxref{GDB/MI Output Syntax, , @sc{gdb/mi} Output | |
21819 | Syntax}). In addition to the prefix, each stream record contains a | |
21820 | @code{@var{string-output}}. This is either raw text (with an implicit new | |
21821 | line) or a quoted C string (which does not contain an implicit newline). | |
21822 | ||
21823 | @table @code | |
21824 | @item "~" @var{string-output} | |
21825 | The console output stream contains text that should be displayed in the | |
21826 | CLI console window. It contains the textual responses to CLI commands. | |
21827 | ||
21828 | @item "@@" @var{string-output} | |
21829 | The target output stream contains any textual output from the running | |
ef21caaf NR |
21830 | target. This is only present when GDB's event loop is truly |
21831 | asynchronous, which is currently only the case for remote targets. | |
922fbb7b AC |
21832 | |
21833 | @item "&" @var{string-output} | |
21834 | The log stream contains debugging messages being produced by @value{GDBN}'s | |
21835 | internals. | |
21836 | @end table | |
21837 | ||
82f68b1c VP |
21838 | @node GDB/MI Async Records |
21839 | @subsection @sc{gdb/mi} Async Records | |
922fbb7b | 21840 | |
82f68b1c VP |
21841 | @cindex async records in @sc{gdb/mi} |
21842 | @cindex @sc{gdb/mi}, async records | |
21843 | @dfn{Async} records are used to notify the @sc{gdb/mi} client of | |
922fbb7b | 21844 | additional changes that have occurred. Those changes can either be a |
82f68b1c | 21845 | consequence of @sc{gdb/mi} commands (e.g., a breakpoint modified) or a result of |
922fbb7b AC |
21846 | target activity (e.g., target stopped). |
21847 | ||
8eb41542 | 21848 | The following is the list of possible async records: |
922fbb7b AC |
21849 | |
21850 | @table @code | |
034dad6f | 21851 | |
e1ac3328 VP |
21852 | @item *running,thread-id="@var{thread}" |
21853 | The target is now running. The @var{thread} field tells which | |
21854 | specific thread is now running, and can be @samp{all} if all threads | |
21855 | are running. The frontend should assume that no interaction with a | |
21856 | running thread is possible after this notification is produced. | |
21857 | The frontend should not assume that this notification is output | |
21858 | only once for any command. @value{GDBN} may emit this notification | |
21859 | several times, either for different threads, because it cannot resume | |
21860 | all threads together, or even for a single thread, if the thread must | |
21861 | be stepped though some code before letting it run freely. | |
21862 | ||
c3b108f7 | 21863 | @item *stopped,reason="@var{reason}",thread-id="@var{id}",stopped-threads="@var{stopped}" |
82f68b1c VP |
21864 | The target has stopped. The @var{reason} field can have one of the |
21865 | following values: | |
034dad6f BR |
21866 | |
21867 | @table @code | |
21868 | @item breakpoint-hit | |
21869 | A breakpoint was reached. | |
21870 | @item watchpoint-trigger | |
21871 | A watchpoint was triggered. | |
21872 | @item read-watchpoint-trigger | |
21873 | A read watchpoint was triggered. | |
21874 | @item access-watchpoint-trigger | |
21875 | An access watchpoint was triggered. | |
21876 | @item function-finished | |
21877 | An -exec-finish or similar CLI command was accomplished. | |
21878 | @item location-reached | |
21879 | An -exec-until or similar CLI command was accomplished. | |
21880 | @item watchpoint-scope | |
21881 | A watchpoint has gone out of scope. | |
21882 | @item end-stepping-range | |
21883 | An -exec-next, -exec-next-instruction, -exec-step, -exec-step-instruction or | |
21884 | similar CLI command was accomplished. | |
21885 | @item exited-signalled | |
21886 | The inferior exited because of a signal. | |
21887 | @item exited | |
21888 | The inferior exited. | |
21889 | @item exited-normally | |
21890 | The inferior exited normally. | |
21891 | @item signal-received | |
21892 | A signal was received by the inferior. | |
922fbb7b AC |
21893 | @end table |
21894 | ||
c3b108f7 VP |
21895 | The @var{id} field identifies the thread that directly caused the stop |
21896 | -- for example by hitting a breakpoint. Depending on whether all-stop | |
21897 | mode is in effect (@pxref{All-Stop Mode}), @value{GDBN} may either | |
21898 | stop all threads, or only the thread that directly triggered the stop. | |
21899 | If all threads are stopped, the @var{stopped} field will have the | |
21900 | value of @code{"all"}. Otherwise, the value of the @var{stopped} | |
21901 | field will be a list of thread identifiers. Presently, this list will | |
21902 | always include a single thread, but frontend should be prepared to see | |
21903 | several threads in the list. | |
21904 | ||
21905 | @item =thread-group-created,id="@var{id}" | |
21906 | @itemx =thread-group-exited,id="@var{id}" | |
21907 | A thread thread group either was attached to, or has exited/detached | |
21908 | from. The @var{id} field contains the @value{GDBN} identifier of the | |
21909 | thread group. | |
21910 | ||
21911 | @item =thread-created,id="@var{id}",group-id="@var{gid}" | |
21912 | @itemx =thread-exited,id="@var{id}",group-id="@var{gid}" | |
82f68b1c | 21913 | A thread either was created, or has exited. The @var{id} field |
c3b108f7 VP |
21914 | contains the @value{GDBN} identifier of the thread. The @var{gid} |
21915 | field identifies the thread group this thread belongs to. | |
66bb093b VP |
21916 | |
21917 | @item =thread-selected,id="@var{id}" | |
21918 | Informs that the selected thread was changed as result of the last | |
21919 | command. This notification is not emitted as result of @code{-thread-select} | |
21920 | command but is emitted whenever an MI command that is not documented | |
21921 | to change the selected thread actually changes it. In particular, | |
21922 | invoking, directly or indirectly (via user-defined command), the CLI | |
21923 | @code{thread} command, will generate this notification. | |
21924 | ||
21925 | We suggest that in response to this notification, front ends | |
21926 | highlight the selected thread and cause subsequent commands to apply to | |
21927 | that thread. | |
21928 | ||
c86cf029 VP |
21929 | @item =library-loaded,... |
21930 | Reports that a new library file was loaded by the program. This | |
21931 | notification has 4 fields---@var{id}, @var{target-name}, | |
134eb42c | 21932 | @var{host-name}, and @var{symbols-loaded}. The @var{id} field is an |
c86cf029 VP |
21933 | opaque identifier of the library. For remote debugging case, |
21934 | @var{target-name} and @var{host-name} fields give the name of the | |
134eb42c VP |
21935 | library file on the target, and on the host respectively. For native |
21936 | debugging, both those fields have the same value. The | |
c86cf029 VP |
21937 | @var{symbols-loaded} field reports if the debug symbols for this |
21938 | library are loaded. | |
21939 | ||
21940 | @item =library-unloaded,... | |
134eb42c | 21941 | Reports that a library was unloaded by the program. This notification |
c86cf029 VP |
21942 | has 3 fields---@var{id}, @var{target-name} and @var{host-name} with |
21943 | the same meaning as for the @code{=library-loaded} notification | |
21944 | ||
82f68b1c VP |
21945 | @end table |
21946 | ||
c3b108f7 VP |
21947 | @node GDB/MI Frame Information |
21948 | @subsection @sc{gdb/mi} Frame Information | |
21949 | ||
21950 | Response from many MI commands includes an information about stack | |
21951 | frame. This information is a tuple that may have the following | |
21952 | fields: | |
21953 | ||
21954 | @table @code | |
21955 | @item level | |
21956 | The level of the stack frame. The innermost frame has the level of | |
21957 | zero. This field is always present. | |
21958 | ||
21959 | @item func | |
21960 | The name of the function corresponding to the frame. This field may | |
21961 | be absent if @value{GDBN} is unable to determine the function name. | |
21962 | ||
21963 | @item addr | |
21964 | The code address for the frame. This field is always present. | |
21965 | ||
21966 | @item file | |
21967 | The name of the source files that correspond to the frame's code | |
21968 | address. This field may be absent. | |
21969 | ||
21970 | @item line | |
21971 | The source line corresponding to the frames' code address. This field | |
21972 | may be absent. | |
21973 | ||
21974 | @item from | |
21975 | The name of the binary file (either executable or shared library) the | |
21976 | corresponds to the frame's code address. This field may be absent. | |
21977 | ||
21978 | @end table | |
82f68b1c | 21979 | |
922fbb7b | 21980 | |
ef21caaf NR |
21981 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21982 | @node GDB/MI Simple Examples | |
21983 | @section Simple Examples of @sc{gdb/mi} Interaction | |
21984 | @cindex @sc{gdb/mi}, simple examples | |
21985 | ||
21986 | This subsection presents several simple examples of interaction using | |
21987 | the @sc{gdb/mi} interface. In these examples, @samp{->} means that the | |
21988 | following line is passed to @sc{gdb/mi} as input, while @samp{<-} means | |
21989 | the output received from @sc{gdb/mi}. | |
21990 | ||
d3e8051b | 21991 | Note the line breaks shown in the examples are here only for |
ef21caaf NR |
21992 | readability, they don't appear in the real output. |
21993 | ||
79a6e687 | 21994 | @subheading Setting a Breakpoint |
ef21caaf NR |
21995 | |
21996 | Setting a breakpoint generates synchronous output which contains detailed | |
21997 | information of the breakpoint. | |
21998 | ||
21999 | @smallexample | |
22000 | -> -break-insert main | |
22001 | <- ^done,bkpt=@{number="1",type="breakpoint",disp="keep", | |
22002 | enabled="y",addr="0x08048564",func="main",file="myprog.c", | |
22003 | fullname="/home/nickrob/myprog.c",line="68",times="0"@} | |
22004 | <- (gdb) | |
22005 | @end smallexample | |
22006 | ||
22007 | @subheading Program Execution | |
22008 | ||
22009 | Program execution generates asynchronous records and MI gives the | |
22010 | reason that execution stopped. | |
22011 | ||
22012 | @smallexample | |
22013 | -> -exec-run | |
22014 | <- ^running | |
22015 | <- (gdb) | |
a47ec5fe | 22016 | <- *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",thread-id="0", |
ef21caaf NR |
22017 | frame=@{addr="0x08048564",func="main", |
22018 | args=[@{name="argc",value="1"@},@{name="argv",value="0xbfc4d4d4"@}], | |
22019 | file="myprog.c",fullname="/home/nickrob/myprog.c",line="68"@} | |
22020 | <- (gdb) | |
22021 | -> -exec-continue | |
22022 | <- ^running | |
22023 | <- (gdb) | |
22024 | <- *stopped,reason="exited-normally" | |
22025 | <- (gdb) | |
22026 | @end smallexample | |
22027 | ||
3f94c067 | 22028 | @subheading Quitting @value{GDBN} |
ef21caaf | 22029 | |
3f94c067 | 22030 | Quitting @value{GDBN} just prints the result class @samp{^exit}. |
ef21caaf NR |
22031 | |
22032 | @smallexample | |
22033 | -> (gdb) | |
22034 | <- -gdb-exit | |
22035 | <- ^exit | |
22036 | @end smallexample | |
22037 | ||
a6b29f87 VP |
22038 | Please note that @samp{^exit} is printed immediately, but it might |
22039 | take some time for @value{GDBN} to actually exit. During that time, @value{GDBN} | |
22040 | performs necessary cleanups, including killing programs being debugged | |
22041 | or disconnecting from debug hardware, so the frontend should wait till | |
22042 | @value{GDBN} exits and should only forcibly kill @value{GDBN} if it | |
22043 | fails to exit in reasonable time. | |
22044 | ||
a2c02241 | 22045 | @subheading A Bad Command |
ef21caaf NR |
22046 | |
22047 | Here's what happens if you pass a non-existent command: | |
22048 | ||
22049 | @smallexample | |
22050 | -> -rubbish | |
22051 | <- ^error,msg="Undefined MI command: rubbish" | |
594fe323 | 22052 | <- (gdb) |
ef21caaf NR |
22053 | @end smallexample |
22054 | ||
22055 | ||
922fbb7b AC |
22056 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
22057 | @node GDB/MI Command Description Format | |
22058 | @section @sc{gdb/mi} Command Description Format | |
22059 | ||
22060 | The remaining sections describe blocks of commands. Each block of | |
22061 | commands is laid out in a fashion similar to this section. | |
22062 | ||
922fbb7b AC |
22063 | @subheading Motivation |
22064 | ||
22065 | The motivation for this collection of commands. | |
22066 | ||
22067 | @subheading Introduction | |
22068 | ||
22069 | A brief introduction to this collection of commands as a whole. | |
22070 | ||
22071 | @subheading Commands | |
22072 | ||
22073 | For each command in the block, the following is described: | |
22074 | ||
22075 | @subsubheading Synopsis | |
22076 | ||
22077 | @smallexample | |
22078 | -command @var{args}@dots{} | |
22079 | @end smallexample | |
22080 | ||
922fbb7b AC |
22081 | @subsubheading Result |
22082 | ||
265eeb58 | 22083 | @subsubheading @value{GDBN} Command |
922fbb7b | 22084 | |
265eeb58 | 22085 | The corresponding @value{GDBN} CLI command(s), if any. |
922fbb7b AC |
22086 | |
22087 | @subsubheading Example | |
22088 | ||
ef21caaf NR |
22089 | Example(s) formatted for readability. Some of the described commands have |
22090 | not been implemented yet and these are labeled N.A.@: (not available). | |
22091 | ||
22092 | ||
922fbb7b | 22093 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
ef21caaf NR |
22094 | @node GDB/MI Breakpoint Commands |
22095 | @section @sc{gdb/mi} Breakpoint Commands | |
922fbb7b AC |
22096 | |
22097 | @cindex breakpoint commands for @sc{gdb/mi} | |
22098 | @cindex @sc{gdb/mi}, breakpoint commands | |
22099 | This section documents @sc{gdb/mi} commands for manipulating | |
22100 | breakpoints. | |
22101 | ||
22102 | @subheading The @code{-break-after} Command | |
22103 | @findex -break-after | |
22104 | ||
22105 | @subsubheading Synopsis | |
22106 | ||
22107 | @smallexample | |
22108 | -break-after @var{number} @var{count} | |
22109 | @end smallexample | |
22110 | ||
22111 | The breakpoint number @var{number} is not in effect until it has been | |
22112 | hit @var{count} times. To see how this is reflected in the output of | |
22113 | the @samp{-break-list} command, see the description of the | |
22114 | @samp{-break-list} command below. | |
22115 | ||
22116 | @subsubheading @value{GDBN} Command | |
22117 | ||
22118 | The corresponding @value{GDBN} command is @samp{ignore}. | |
22119 | ||
22120 | @subsubheading Example | |
22121 | ||
22122 | @smallexample | |
594fe323 | 22123 | (gdb) |
922fbb7b | 22124 | -break-insert main |
a47ec5fe AR |
22125 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep", |
22126 | enabled="y",addr="0x000100d0",func="main",file="hello.c", | |
948d5102 | 22127 | fullname="/home/foo/hello.c",line="5",times="0"@} |
594fe323 | 22128 | (gdb) |
922fbb7b AC |
22129 | -break-after 1 3 |
22130 | ~ | |
22131 | ^done | |
594fe323 | 22132 | (gdb) |
922fbb7b AC |
22133 | -break-list |
22134 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22135 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22136 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22137 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22138 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22139 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22140 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22141 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22142 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
22143 | line="5",times="0",ignore="3"@}]@} | |
594fe323 | 22144 | (gdb) |
922fbb7b AC |
22145 | @end smallexample |
22146 | ||
22147 | @ignore | |
22148 | @subheading The @code{-break-catch} Command | |
22149 | @findex -break-catch | |
48cb2d85 | 22150 | @end ignore |
922fbb7b AC |
22151 | |
22152 | @subheading The @code{-break-commands} Command | |
22153 | @findex -break-commands | |
922fbb7b | 22154 | |
48cb2d85 VP |
22155 | @subsubheading Synopsis |
22156 | ||
22157 | @smallexample | |
22158 | -break-commands @var{number} [ @var{command1} ... @var{commandN} ] | |
22159 | @end smallexample | |
22160 | ||
22161 | Specifies the CLI commands that should be executed when breakpoint | |
22162 | @var{number} is hit. The parameters @var{command1} to @var{commandN} | |
22163 | are the commands. If no command is specified, any previously-set | |
22164 | commands are cleared. @xref{Break Commands}. Typical use of this | |
22165 | functionality is tracing a program, that is, printing of values of | |
22166 | some variables whenever breakpoint is hit and then continuing. | |
22167 | ||
22168 | @subsubheading @value{GDBN} Command | |
22169 | ||
22170 | The corresponding @value{GDBN} command is @samp{commands}. | |
22171 | ||
22172 | @subsubheading Example | |
22173 | ||
22174 | @smallexample | |
22175 | (gdb) | |
22176 | -break-insert main | |
22177 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep", | |
22178 | enabled="y",addr="0x000100d0",func="main",file="hello.c", | |
22179 | fullname="/home/foo/hello.c",line="5",times="0"@} | |
22180 | (gdb) | |
22181 | -break-commands 1 "print v" "continue" | |
22182 | ^done | |
22183 | (gdb) | |
22184 | @end smallexample | |
922fbb7b AC |
22185 | |
22186 | @subheading The @code{-break-condition} Command | |
22187 | @findex -break-condition | |
22188 | ||
22189 | @subsubheading Synopsis | |
22190 | ||
22191 | @smallexample | |
22192 | -break-condition @var{number} @var{expr} | |
22193 | @end smallexample | |
22194 | ||
22195 | Breakpoint @var{number} will stop the program only if the condition in | |
22196 | @var{expr} is true. The condition becomes part of the | |
22197 | @samp{-break-list} output (see the description of the @samp{-break-list} | |
22198 | command below). | |
22199 | ||
22200 | @subsubheading @value{GDBN} Command | |
22201 | ||
22202 | The corresponding @value{GDBN} command is @samp{condition}. | |
22203 | ||
22204 | @subsubheading Example | |
22205 | ||
22206 | @smallexample | |
594fe323 | 22207 | (gdb) |
922fbb7b AC |
22208 | -break-condition 1 1 |
22209 | ^done | |
594fe323 | 22210 | (gdb) |
922fbb7b AC |
22211 | -break-list |
22212 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22213 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22214 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22215 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22216 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22217 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22218 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22219 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22220 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
22221 | line="5",cond="1",times="0",ignore="3"@}]@} | |
594fe323 | 22222 | (gdb) |
922fbb7b AC |
22223 | @end smallexample |
22224 | ||
22225 | @subheading The @code{-break-delete} Command | |
22226 | @findex -break-delete | |
22227 | ||
22228 | @subsubheading Synopsis | |
22229 | ||
22230 | @smallexample | |
22231 | -break-delete ( @var{breakpoint} )+ | |
22232 | @end smallexample | |
22233 | ||
22234 | Delete the breakpoint(s) whose number(s) are specified in the argument | |
22235 | list. This is obviously reflected in the breakpoint list. | |
22236 | ||
79a6e687 | 22237 | @subsubheading @value{GDBN} Command |
922fbb7b AC |
22238 | |
22239 | The corresponding @value{GDBN} command is @samp{delete}. | |
22240 | ||
22241 | @subsubheading Example | |
22242 | ||
22243 | @smallexample | |
594fe323 | 22244 | (gdb) |
922fbb7b AC |
22245 | -break-delete 1 |
22246 | ^done | |
594fe323 | 22247 | (gdb) |
922fbb7b AC |
22248 | -break-list |
22249 | ^done,BreakpointTable=@{nr_rows="0",nr_cols="6", | |
22250 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22251 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22252 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22253 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22254 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22255 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22256 | body=[]@} | |
594fe323 | 22257 | (gdb) |
922fbb7b AC |
22258 | @end smallexample |
22259 | ||
22260 | @subheading The @code{-break-disable} Command | |
22261 | @findex -break-disable | |
22262 | ||
22263 | @subsubheading Synopsis | |
22264 | ||
22265 | @smallexample | |
22266 | -break-disable ( @var{breakpoint} )+ | |
22267 | @end smallexample | |
22268 | ||
22269 | Disable the named @var{breakpoint}(s). The field @samp{enabled} in the | |
22270 | break list is now set to @samp{n} for the named @var{breakpoint}(s). | |
22271 | ||
22272 | @subsubheading @value{GDBN} Command | |
22273 | ||
22274 | The corresponding @value{GDBN} command is @samp{disable}. | |
22275 | ||
22276 | @subsubheading Example | |
22277 | ||
22278 | @smallexample | |
594fe323 | 22279 | (gdb) |
922fbb7b AC |
22280 | -break-disable 2 |
22281 | ^done | |
594fe323 | 22282 | (gdb) |
922fbb7b AC |
22283 | -break-list |
22284 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22285 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22286 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22287 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22288 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22289 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22290 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22291 | body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="n", | |
948d5102 NR |
22292 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
22293 | line="5",times="0"@}]@} | |
594fe323 | 22294 | (gdb) |
922fbb7b AC |
22295 | @end smallexample |
22296 | ||
22297 | @subheading The @code{-break-enable} Command | |
22298 | @findex -break-enable | |
22299 | ||
22300 | @subsubheading Synopsis | |
22301 | ||
22302 | @smallexample | |
22303 | -break-enable ( @var{breakpoint} )+ | |
22304 | @end smallexample | |
22305 | ||
22306 | Enable (previously disabled) @var{breakpoint}(s). | |
22307 | ||
22308 | @subsubheading @value{GDBN} Command | |
22309 | ||
22310 | The corresponding @value{GDBN} command is @samp{enable}. | |
22311 | ||
22312 | @subsubheading Example | |
22313 | ||
22314 | @smallexample | |
594fe323 | 22315 | (gdb) |
922fbb7b AC |
22316 | -break-enable 2 |
22317 | ^done | |
594fe323 | 22318 | (gdb) |
922fbb7b AC |
22319 | -break-list |
22320 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22321 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22322 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22323 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22324 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22325 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22326 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22327 | body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22328 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
22329 | line="5",times="0"@}]@} | |
594fe323 | 22330 | (gdb) |
922fbb7b AC |
22331 | @end smallexample |
22332 | ||
22333 | @subheading The @code{-break-info} Command | |
22334 | @findex -break-info | |
22335 | ||
22336 | @subsubheading Synopsis | |
22337 | ||
22338 | @smallexample | |
22339 | -break-info @var{breakpoint} | |
22340 | @end smallexample | |
22341 | ||
22342 | @c REDUNDANT??? | |
22343 | Get information about a single breakpoint. | |
22344 | ||
79a6e687 | 22345 | @subsubheading @value{GDBN} Command |
922fbb7b AC |
22346 | |
22347 | The corresponding @value{GDBN} command is @samp{info break @var{breakpoint}}. | |
22348 | ||
22349 | @subsubheading Example | |
22350 | N.A. | |
22351 | ||
22352 | @subheading The @code{-break-insert} Command | |
22353 | @findex -break-insert | |
22354 | ||
22355 | @subsubheading Synopsis | |
22356 | ||
22357 | @smallexample | |
41447f92 | 22358 | -break-insert [ -t ] [ -h ] [ -f ] [ -d ] |
922fbb7b | 22359 | [ -c @var{condition} ] [ -i @var{ignore-count} ] |
afe8ab22 | 22360 | [ -p @var{thread} ] [ @var{location} ] |
922fbb7b AC |
22361 | @end smallexample |
22362 | ||
22363 | @noindent | |
afe8ab22 | 22364 | If specified, @var{location}, can be one of: |
922fbb7b AC |
22365 | |
22366 | @itemize @bullet | |
22367 | @item function | |
22368 | @c @item +offset | |
22369 | @c @item -offset | |
22370 | @c @item linenum | |
22371 | @item filename:linenum | |
22372 | @item filename:function | |
22373 | @item *address | |
22374 | @end itemize | |
22375 | ||
22376 | The possible optional parameters of this command are: | |
22377 | ||
22378 | @table @samp | |
22379 | @item -t | |
948d5102 | 22380 | Insert a temporary breakpoint. |
922fbb7b AC |
22381 | @item -h |
22382 | Insert a hardware breakpoint. | |
22383 | @item -c @var{condition} | |
22384 | Make the breakpoint conditional on @var{condition}. | |
22385 | @item -i @var{ignore-count} | |
22386 | Initialize the @var{ignore-count}. | |
afe8ab22 VP |
22387 | @item -f |
22388 | If @var{location} cannot be parsed (for example if it | |
22389 | refers to unknown files or functions), create a pending | |
22390 | breakpoint. Without this flag, @value{GDBN} will report | |
22391 | an error, and won't create a breakpoint, if @var{location} | |
22392 | cannot be parsed. | |
41447f92 VP |
22393 | @item -d |
22394 | Create a disabled breakpoint. | |
922fbb7b AC |
22395 | @end table |
22396 | ||
22397 | @subsubheading Result | |
22398 | ||
22399 | The result is in the form: | |
22400 | ||
22401 | @smallexample | |
948d5102 NR |
22402 | ^done,bkpt=@{number="@var{number}",type="@var{type}",disp="del"|"keep", |
22403 | enabled="y"|"n",addr="@var{hex}",func="@var{funcname}",file="@var{filename}", | |
ef21caaf NR |
22404 | fullname="@var{full_filename}",line="@var{lineno}",[thread="@var{threadno},] |
22405 | times="@var{times}"@} | |
922fbb7b AC |
22406 | @end smallexample |
22407 | ||
22408 | @noindent | |
948d5102 NR |
22409 | where @var{number} is the @value{GDBN} number for this breakpoint, |
22410 | @var{funcname} is the name of the function where the breakpoint was | |
22411 | inserted, @var{filename} is the name of the source file which contains | |
22412 | this function, @var{lineno} is the source line number within that file | |
22413 | and @var{times} the number of times that the breakpoint has been hit | |
22414 | (always 0 for -break-insert but may be greater for -break-info or -break-list | |
22415 | which use the same output). | |
922fbb7b AC |
22416 | |
22417 | Note: this format is open to change. | |
22418 | @c An out-of-band breakpoint instead of part of the result? | |
22419 | ||
22420 | @subsubheading @value{GDBN} Command | |
22421 | ||
22422 | The corresponding @value{GDBN} commands are @samp{break}, @samp{tbreak}, | |
22423 | @samp{hbreak}, @samp{thbreak}, and @samp{rbreak}. | |
22424 | ||
22425 | @subsubheading Example | |
22426 | ||
22427 | @smallexample | |
594fe323 | 22428 | (gdb) |
922fbb7b | 22429 | -break-insert main |
948d5102 NR |
22430 | ^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c", |
22431 | fullname="/home/foo/recursive2.c,line="4",times="0"@} | |
594fe323 | 22432 | (gdb) |
922fbb7b | 22433 | -break-insert -t foo |
948d5102 NR |
22434 | ^done,bkpt=@{number="2",addr="0x00010774",file="recursive2.c", |
22435 | fullname="/home/foo/recursive2.c,line="11",times="0"@} | |
594fe323 | 22436 | (gdb) |
922fbb7b AC |
22437 | -break-list |
22438 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22439 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22440 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22441 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22442 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22443 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22444 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22445 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22446 | addr="0x0001072c", func="main",file="recursive2.c", |
22447 | fullname="/home/foo/recursive2.c,"line="4",times="0"@}, | |
922fbb7b | 22448 | bkpt=@{number="2",type="breakpoint",disp="del",enabled="y", |
948d5102 NR |
22449 | addr="0x00010774",func="foo",file="recursive2.c", |
22450 | fullname="/home/foo/recursive2.c",line="11",times="0"@}]@} | |
594fe323 | 22451 | (gdb) |
922fbb7b AC |
22452 | -break-insert -r foo.* |
22453 | ~int foo(int, int); | |
948d5102 NR |
22454 | ^done,bkpt=@{number="3",addr="0x00010774",file="recursive2.c, |
22455 | "fullname="/home/foo/recursive2.c",line="11",times="0"@} | |
594fe323 | 22456 | (gdb) |
922fbb7b AC |
22457 | @end smallexample |
22458 | ||
22459 | @subheading The @code{-break-list} Command | |
22460 | @findex -break-list | |
22461 | ||
22462 | @subsubheading Synopsis | |
22463 | ||
22464 | @smallexample | |
22465 | -break-list | |
22466 | @end smallexample | |
22467 | ||
22468 | Displays the list of inserted breakpoints, showing the following fields: | |
22469 | ||
22470 | @table @samp | |
22471 | @item Number | |
22472 | number of the breakpoint | |
22473 | @item Type | |
22474 | type of the breakpoint: @samp{breakpoint} or @samp{watchpoint} | |
22475 | @item Disposition | |
22476 | should the breakpoint be deleted or disabled when it is hit: @samp{keep} | |
22477 | or @samp{nokeep} | |
22478 | @item Enabled | |
22479 | is the breakpoint enabled or no: @samp{y} or @samp{n} | |
22480 | @item Address | |
22481 | memory location at which the breakpoint is set | |
22482 | @item What | |
22483 | logical location of the breakpoint, expressed by function name, file | |
22484 | name, line number | |
22485 | @item Times | |
22486 | number of times the breakpoint has been hit | |
22487 | @end table | |
22488 | ||
22489 | If there are no breakpoints or watchpoints, the @code{BreakpointTable} | |
22490 | @code{body} field is an empty list. | |
22491 | ||
22492 | @subsubheading @value{GDBN} Command | |
22493 | ||
22494 | The corresponding @value{GDBN} command is @samp{info break}. | |
22495 | ||
22496 | @subsubheading Example | |
22497 | ||
22498 | @smallexample | |
594fe323 | 22499 | (gdb) |
922fbb7b AC |
22500 | -break-list |
22501 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22502 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22503 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22504 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22505 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22506 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22507 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22508 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22509 | addr="0x000100d0",func="main",file="hello.c",line="5",times="0"@}, | |
22510 | bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22511 | addr="0x00010114",func="foo",file="hello.c",fullname="/home/foo/hello.c", |
22512 | line="13",times="0"@}]@} | |
594fe323 | 22513 | (gdb) |
922fbb7b AC |
22514 | @end smallexample |
22515 | ||
22516 | Here's an example of the result when there are no breakpoints: | |
22517 | ||
22518 | @smallexample | |
594fe323 | 22519 | (gdb) |
922fbb7b AC |
22520 | -break-list |
22521 | ^done,BreakpointTable=@{nr_rows="0",nr_cols="6", | |
22522 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22523 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22524 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22525 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22526 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22527 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22528 | body=[]@} | |
594fe323 | 22529 | (gdb) |
922fbb7b AC |
22530 | @end smallexample |
22531 | ||
22532 | @subheading The @code{-break-watch} Command | |
22533 | @findex -break-watch | |
22534 | ||
22535 | @subsubheading Synopsis | |
22536 | ||
22537 | @smallexample | |
22538 | -break-watch [ -a | -r ] | |
22539 | @end smallexample | |
22540 | ||
22541 | Create a watchpoint. With the @samp{-a} option it will create an | |
d3e8051b | 22542 | @dfn{access} watchpoint, i.e., a watchpoint that triggers either on a |
922fbb7b | 22543 | read from or on a write to the memory location. With the @samp{-r} |
d3e8051b | 22544 | option, the watchpoint created is a @dfn{read} watchpoint, i.e., it will |
922fbb7b AC |
22545 | trigger only when the memory location is accessed for reading. Without |
22546 | either of the options, the watchpoint created is a regular watchpoint, | |
d3e8051b | 22547 | i.e., it will trigger when the memory location is accessed for writing. |
79a6e687 | 22548 | @xref{Set Watchpoints, , Setting Watchpoints}. |
922fbb7b AC |
22549 | |
22550 | Note that @samp{-break-list} will report a single list of watchpoints and | |
22551 | breakpoints inserted. | |
22552 | ||
22553 | @subsubheading @value{GDBN} Command | |
22554 | ||
22555 | The corresponding @value{GDBN} commands are @samp{watch}, @samp{awatch}, and | |
22556 | @samp{rwatch}. | |
22557 | ||
22558 | @subsubheading Example | |
22559 | ||
22560 | Setting a watchpoint on a variable in the @code{main} function: | |
22561 | ||
22562 | @smallexample | |
594fe323 | 22563 | (gdb) |
922fbb7b AC |
22564 | -break-watch x |
22565 | ^done,wpt=@{number="2",exp="x"@} | |
594fe323 | 22566 | (gdb) |
922fbb7b AC |
22567 | -exec-continue |
22568 | ^running | |
0869d01b NR |
22569 | (gdb) |
22570 | *stopped,reason="watchpoint-trigger",wpt=@{number="2",exp="x"@}, | |
922fbb7b | 22571 | value=@{old="-268439212",new="55"@}, |
76ff342d | 22572 | frame=@{func="main",args=[],file="recursive2.c", |
948d5102 | 22573 | fullname="/home/foo/bar/recursive2.c",line="5"@} |
594fe323 | 22574 | (gdb) |
922fbb7b AC |
22575 | @end smallexample |
22576 | ||
22577 | Setting a watchpoint on a variable local to a function. @value{GDBN} will stop | |
22578 | the program execution twice: first for the variable changing value, then | |
22579 | for the watchpoint going out of scope. | |
22580 | ||
22581 | @smallexample | |
594fe323 | 22582 | (gdb) |
922fbb7b AC |
22583 | -break-watch C |
22584 | ^done,wpt=@{number="5",exp="C"@} | |
594fe323 | 22585 | (gdb) |
922fbb7b AC |
22586 | -exec-continue |
22587 | ^running | |
0869d01b NR |
22588 | (gdb) |
22589 | *stopped,reason="watchpoint-trigger", | |
922fbb7b AC |
22590 | wpt=@{number="5",exp="C"@},value=@{old="-276895068",new="3"@}, |
22591 | frame=@{func="callee4",args=[], | |
76ff342d DJ |
22592 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22593 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@} | |
594fe323 | 22594 | (gdb) |
922fbb7b AC |
22595 | -exec-continue |
22596 | ^running | |
0869d01b NR |
22597 | (gdb) |
22598 | *stopped,reason="watchpoint-scope",wpnum="5", | |
922fbb7b AC |
22599 | frame=@{func="callee3",args=[@{name="strarg", |
22600 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
22601 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22602 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 22603 | (gdb) |
922fbb7b AC |
22604 | @end smallexample |
22605 | ||
22606 | Listing breakpoints and watchpoints, at different points in the program | |
22607 | execution. Note that once the watchpoint goes out of scope, it is | |
22608 | deleted. | |
22609 | ||
22610 | @smallexample | |
594fe323 | 22611 | (gdb) |
922fbb7b AC |
22612 | -break-watch C |
22613 | ^done,wpt=@{number="2",exp="C"@} | |
594fe323 | 22614 | (gdb) |
922fbb7b AC |
22615 | -break-list |
22616 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22617 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22618 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22619 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22620 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22621 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22622 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22623 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22624 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22625 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22626 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c"line="8",times="1"@}, | |
922fbb7b AC |
22627 | bkpt=@{number="2",type="watchpoint",disp="keep", |
22628 | enabled="y",addr="",what="C",times="0"@}]@} | |
594fe323 | 22629 | (gdb) |
922fbb7b AC |
22630 | -exec-continue |
22631 | ^running | |
0869d01b NR |
22632 | (gdb) |
22633 | *stopped,reason="watchpoint-trigger",wpt=@{number="2",exp="C"@}, | |
922fbb7b AC |
22634 | value=@{old="-276895068",new="3"@}, |
22635 | frame=@{func="callee4",args=[], | |
76ff342d DJ |
22636 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22637 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@} | |
594fe323 | 22638 | (gdb) |
922fbb7b AC |
22639 | -break-list |
22640 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22641 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22642 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22643 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22644 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22645 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22646 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22647 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22648 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22649 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22650 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"@}, | |
922fbb7b AC |
22651 | bkpt=@{number="2",type="watchpoint",disp="keep", |
22652 | enabled="y",addr="",what="C",times="-5"@}]@} | |
594fe323 | 22653 | (gdb) |
922fbb7b AC |
22654 | -exec-continue |
22655 | ^running | |
22656 | ^done,reason="watchpoint-scope",wpnum="2", | |
22657 | frame=@{func="callee3",args=[@{name="strarg", | |
22658 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
22659 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22660 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 22661 | (gdb) |
922fbb7b AC |
22662 | -break-list |
22663 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22664 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22665 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22666 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22667 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22668 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22669 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22670 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22671 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22672 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22673 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8", | |
22674 | times="1"@}]@} | |
594fe323 | 22675 | (gdb) |
922fbb7b AC |
22676 | @end smallexample |
22677 | ||
22678 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
a2c02241 NR |
22679 | @node GDB/MI Program Context |
22680 | @section @sc{gdb/mi} Program Context | |
922fbb7b | 22681 | |
a2c02241 NR |
22682 | @subheading The @code{-exec-arguments} Command |
22683 | @findex -exec-arguments | |
922fbb7b | 22684 | |
922fbb7b AC |
22685 | |
22686 | @subsubheading Synopsis | |
22687 | ||
22688 | @smallexample | |
a2c02241 | 22689 | -exec-arguments @var{args} |
922fbb7b AC |
22690 | @end smallexample |
22691 | ||
a2c02241 NR |
22692 | Set the inferior program arguments, to be used in the next |
22693 | @samp{-exec-run}. | |
922fbb7b | 22694 | |
a2c02241 | 22695 | @subsubheading @value{GDBN} Command |
922fbb7b | 22696 | |
a2c02241 | 22697 | The corresponding @value{GDBN} command is @samp{set args}. |
922fbb7b | 22698 | |
a2c02241 | 22699 | @subsubheading Example |
922fbb7b | 22700 | |
fbc5282e MK |
22701 | @smallexample |
22702 | (gdb) | |
22703 | -exec-arguments -v word | |
22704 | ^done | |
22705 | (gdb) | |
22706 | @end smallexample | |
922fbb7b | 22707 | |
a2c02241 | 22708 | |
9901a55b | 22709 | @ignore |
a2c02241 NR |
22710 | @subheading The @code{-exec-show-arguments} Command |
22711 | @findex -exec-show-arguments | |
22712 | ||
22713 | @subsubheading Synopsis | |
22714 | ||
22715 | @smallexample | |
22716 | -exec-show-arguments | |
22717 | @end smallexample | |
22718 | ||
22719 | Print the arguments of the program. | |
922fbb7b AC |
22720 | |
22721 | @subsubheading @value{GDBN} Command | |
22722 | ||
a2c02241 | 22723 | The corresponding @value{GDBN} command is @samp{show args}. |
922fbb7b AC |
22724 | |
22725 | @subsubheading Example | |
a2c02241 | 22726 | N.A. |
9901a55b | 22727 | @end ignore |
922fbb7b | 22728 | |
922fbb7b | 22729 | |
a2c02241 NR |
22730 | @subheading The @code{-environment-cd} Command |
22731 | @findex -environment-cd | |
922fbb7b | 22732 | |
a2c02241 | 22733 | @subsubheading Synopsis |
922fbb7b AC |
22734 | |
22735 | @smallexample | |
a2c02241 | 22736 | -environment-cd @var{pathdir} |
922fbb7b AC |
22737 | @end smallexample |
22738 | ||
a2c02241 | 22739 | Set @value{GDBN}'s working directory. |
922fbb7b | 22740 | |
a2c02241 | 22741 | @subsubheading @value{GDBN} Command |
922fbb7b | 22742 | |
a2c02241 NR |
22743 | The corresponding @value{GDBN} command is @samp{cd}. |
22744 | ||
22745 | @subsubheading Example | |
922fbb7b AC |
22746 | |
22747 | @smallexample | |
594fe323 | 22748 | (gdb) |
a2c02241 NR |
22749 | -environment-cd /kwikemart/marge/ezannoni/flathead-dev/devo/gdb |
22750 | ^done | |
594fe323 | 22751 | (gdb) |
922fbb7b AC |
22752 | @end smallexample |
22753 | ||
22754 | ||
a2c02241 NR |
22755 | @subheading The @code{-environment-directory} Command |
22756 | @findex -environment-directory | |
922fbb7b AC |
22757 | |
22758 | @subsubheading Synopsis | |
22759 | ||
22760 | @smallexample | |
a2c02241 | 22761 | -environment-directory [ -r ] [ @var{pathdir} ]+ |
922fbb7b AC |
22762 | @end smallexample |
22763 | ||
a2c02241 NR |
22764 | Add directories @var{pathdir} to beginning of search path for source files. |
22765 | If the @samp{-r} option is used, the search path is reset to the default | |
22766 | search path. If directories @var{pathdir} are supplied in addition to the | |
22767 | @samp{-r} option, the search path is first reset and then addition | |
22768 | occurs as normal. | |
22769 | Multiple directories may be specified, separated by blanks. Specifying | |
22770 | multiple directories in a single command | |
22771 | results in the directories added to the beginning of the | |
22772 | search path in the same order they were presented in the command. | |
22773 | If blanks are needed as | |
22774 | part of a directory name, double-quotes should be used around | |
22775 | the name. In the command output, the path will show up separated | |
d3e8051b | 22776 | by the system directory-separator character. The directory-separator |
a2c02241 NR |
22777 | character must not be used |
22778 | in any directory name. | |
22779 | If no directories are specified, the current search path is displayed. | |
922fbb7b AC |
22780 | |
22781 | @subsubheading @value{GDBN} Command | |
22782 | ||
a2c02241 | 22783 | The corresponding @value{GDBN} command is @samp{dir}. |
922fbb7b AC |
22784 | |
22785 | @subsubheading Example | |
22786 | ||
922fbb7b | 22787 | @smallexample |
594fe323 | 22788 | (gdb) |
a2c02241 NR |
22789 | -environment-directory /kwikemart/marge/ezannoni/flathead-dev/devo/gdb |
22790 | ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" | |
594fe323 | 22791 | (gdb) |
a2c02241 NR |
22792 | -environment-directory "" |
22793 | ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" | |
594fe323 | 22794 | (gdb) |
a2c02241 NR |
22795 | -environment-directory -r /home/jjohnstn/src/gdb /usr/src |
22796 | ^done,source-path="/home/jjohnstn/src/gdb:/usr/src:$cdir:$cwd" | |
594fe323 | 22797 | (gdb) |
a2c02241 NR |
22798 | -environment-directory -r |
22799 | ^done,source-path="$cdir:$cwd" | |
594fe323 | 22800 | (gdb) |
922fbb7b AC |
22801 | @end smallexample |
22802 | ||
22803 | ||
a2c02241 NR |
22804 | @subheading The @code{-environment-path} Command |
22805 | @findex -environment-path | |
922fbb7b AC |
22806 | |
22807 | @subsubheading Synopsis | |
22808 | ||
22809 | @smallexample | |
a2c02241 | 22810 | -environment-path [ -r ] [ @var{pathdir} ]+ |
922fbb7b AC |
22811 | @end smallexample |
22812 | ||
a2c02241 NR |
22813 | Add directories @var{pathdir} to beginning of search path for object files. |
22814 | If the @samp{-r} option is used, the search path is reset to the original | |
22815 | search path that existed at gdb start-up. If directories @var{pathdir} are | |
22816 | supplied in addition to the | |
22817 | @samp{-r} option, the search path is first reset and then addition | |
22818 | occurs as normal. | |
22819 | Multiple directories may be specified, separated by blanks. Specifying | |
22820 | multiple directories in a single command | |
22821 | results in the directories added to the beginning of the | |
22822 | search path in the same order they were presented in the command. | |
22823 | If blanks are needed as | |
22824 | part of a directory name, double-quotes should be used around | |
22825 | the name. In the command output, the path will show up separated | |
d3e8051b | 22826 | by the system directory-separator character. The directory-separator |
a2c02241 NR |
22827 | character must not be used |
22828 | in any directory name. | |
22829 | If no directories are specified, the current path is displayed. | |
22830 | ||
922fbb7b AC |
22831 | |
22832 | @subsubheading @value{GDBN} Command | |
22833 | ||
a2c02241 | 22834 | The corresponding @value{GDBN} command is @samp{path}. |
922fbb7b AC |
22835 | |
22836 | @subsubheading Example | |
22837 | ||
922fbb7b | 22838 | @smallexample |
594fe323 | 22839 | (gdb) |
a2c02241 NR |
22840 | -environment-path |
22841 | ^done,path="/usr/bin" | |
594fe323 | 22842 | (gdb) |
a2c02241 NR |
22843 | -environment-path /kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb /bin |
22844 | ^done,path="/kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb:/bin:/usr/bin" | |
594fe323 | 22845 | (gdb) |
a2c02241 NR |
22846 | -environment-path -r /usr/local/bin |
22847 | ^done,path="/usr/local/bin:/usr/bin" | |
594fe323 | 22848 | (gdb) |
922fbb7b AC |
22849 | @end smallexample |
22850 | ||
22851 | ||
a2c02241 NR |
22852 | @subheading The @code{-environment-pwd} Command |
22853 | @findex -environment-pwd | |
922fbb7b AC |
22854 | |
22855 | @subsubheading Synopsis | |
22856 | ||
22857 | @smallexample | |
a2c02241 | 22858 | -environment-pwd |
922fbb7b AC |
22859 | @end smallexample |
22860 | ||
a2c02241 | 22861 | Show the current working directory. |
922fbb7b | 22862 | |
79a6e687 | 22863 | @subsubheading @value{GDBN} Command |
922fbb7b | 22864 | |
a2c02241 | 22865 | The corresponding @value{GDBN} command is @samp{pwd}. |
922fbb7b AC |
22866 | |
22867 | @subsubheading Example | |
22868 | ||
922fbb7b | 22869 | @smallexample |
594fe323 | 22870 | (gdb) |
a2c02241 NR |
22871 | -environment-pwd |
22872 | ^done,cwd="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb" | |
594fe323 | 22873 | (gdb) |
922fbb7b AC |
22874 | @end smallexample |
22875 | ||
a2c02241 NR |
22876 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
22877 | @node GDB/MI Thread Commands | |
22878 | @section @sc{gdb/mi} Thread Commands | |
22879 | ||
22880 | ||
22881 | @subheading The @code{-thread-info} Command | |
22882 | @findex -thread-info | |
922fbb7b AC |
22883 | |
22884 | @subsubheading Synopsis | |
22885 | ||
22886 | @smallexample | |
8e8901c5 | 22887 | -thread-info [ @var{thread-id} ] |
922fbb7b AC |
22888 | @end smallexample |
22889 | ||
8e8901c5 VP |
22890 | Reports information about either a specific thread, if |
22891 | the @var{thread-id} parameter is present, or about all | |
22892 | threads. When printing information about all threads, | |
22893 | also reports the current thread. | |
22894 | ||
79a6e687 | 22895 | @subsubheading @value{GDBN} Command |
922fbb7b | 22896 | |
8e8901c5 VP |
22897 | The @samp{info thread} command prints the same information |
22898 | about all threads. | |
922fbb7b AC |
22899 | |
22900 | @subsubheading Example | |
922fbb7b AC |
22901 | |
22902 | @smallexample | |
8e8901c5 VP |
22903 | -thread-info |
22904 | ^done,threads=[ | |
22905 | @{id="2",target-id="Thread 0xb7e14b90 (LWP 21257)", | |
c3b108f7 | 22906 | frame=@{level="0",addr="0xffffe410",func="__kernel_vsyscall",args=[]@},state="running"@}, |
8e8901c5 VP |
22907 | @{id="1",target-id="Thread 0xb7e156b0 (LWP 21254)", |
22908 | frame=@{level="0",addr="0x0804891f",func="foo",args=[@{name="i",value="10"@}], | |
c3b108f7 | 22909 | file="/tmp/a.c",fullname="/tmp/a.c",line="158"@},state="running"@}], |
8e8901c5 VP |
22910 | current-thread-id="1" |
22911 | (gdb) | |
922fbb7b AC |
22912 | @end smallexample |
22913 | ||
c3b108f7 VP |
22914 | The @samp{state} field may have the following values: |
22915 | ||
22916 | @table @code | |
22917 | @item stopped | |
22918 | The thread is stopped. Frame information is available for stopped | |
22919 | threads. | |
22920 | ||
22921 | @item running | |
22922 | The thread is running. There's no frame information for running | |
22923 | threads. | |
22924 | ||
22925 | @end table | |
22926 | ||
a2c02241 NR |
22927 | @subheading The @code{-thread-list-ids} Command |
22928 | @findex -thread-list-ids | |
922fbb7b | 22929 | |
a2c02241 | 22930 | @subsubheading Synopsis |
922fbb7b | 22931 | |
a2c02241 NR |
22932 | @smallexample |
22933 | -thread-list-ids | |
22934 | @end smallexample | |
922fbb7b | 22935 | |
a2c02241 NR |
22936 | Produces a list of the currently known @value{GDBN} thread ids. At the |
22937 | end of the list it also prints the total number of such threads. | |
922fbb7b | 22938 | |
c3b108f7 VP |
22939 | This command is retained for historical reasons, the |
22940 | @code{-thread-info} command should be used instead. | |
22941 | ||
922fbb7b AC |
22942 | @subsubheading @value{GDBN} Command |
22943 | ||
a2c02241 | 22944 | Part of @samp{info threads} supplies the same information. |
922fbb7b AC |
22945 | |
22946 | @subsubheading Example | |
22947 | ||
922fbb7b | 22948 | @smallexample |
594fe323 | 22949 | (gdb) |
a2c02241 NR |
22950 | -thread-list-ids |
22951 | ^done,thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@}, | |
592375cd | 22952 | current-thread-id="1",number-of-threads="3" |
594fe323 | 22953 | (gdb) |
922fbb7b AC |
22954 | @end smallexample |
22955 | ||
a2c02241 NR |
22956 | |
22957 | @subheading The @code{-thread-select} Command | |
22958 | @findex -thread-select | |
922fbb7b AC |
22959 | |
22960 | @subsubheading Synopsis | |
22961 | ||
22962 | @smallexample | |
a2c02241 | 22963 | -thread-select @var{threadnum} |
922fbb7b AC |
22964 | @end smallexample |
22965 | ||
a2c02241 NR |
22966 | Make @var{threadnum} the current thread. It prints the number of the new |
22967 | current thread, and the topmost frame for that thread. | |
922fbb7b | 22968 | |
c3b108f7 VP |
22969 | This command is deprecated in favor of explicitly using the |
22970 | @samp{--thread} option to each command. | |
22971 | ||
922fbb7b AC |
22972 | @subsubheading @value{GDBN} Command |
22973 | ||
a2c02241 | 22974 | The corresponding @value{GDBN} command is @samp{thread}. |
922fbb7b AC |
22975 | |
22976 | @subsubheading Example | |
922fbb7b AC |
22977 | |
22978 | @smallexample | |
594fe323 | 22979 | (gdb) |
a2c02241 NR |
22980 | -exec-next |
22981 | ^running | |
594fe323 | 22982 | (gdb) |
a2c02241 NR |
22983 | *stopped,reason="end-stepping-range",thread-id="2",line="187", |
22984 | file="../../../devo/gdb/testsuite/gdb.threads/linux-dp.c" | |
594fe323 | 22985 | (gdb) |
a2c02241 NR |
22986 | -thread-list-ids |
22987 | ^done, | |
22988 | thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@}, | |
22989 | number-of-threads="3" | |
594fe323 | 22990 | (gdb) |
a2c02241 NR |
22991 | -thread-select 3 |
22992 | ^done,new-thread-id="3", | |
22993 | frame=@{level="0",func="vprintf", | |
22994 | args=[@{name="format",value="0x8048e9c \"%*s%c %d %c\\n\""@}, | |
22995 | @{name="arg",value="0x2"@}],file="vprintf.c",line="31"@} | |
594fe323 | 22996 | (gdb) |
922fbb7b AC |
22997 | @end smallexample |
22998 | ||
a2c02241 NR |
22999 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
23000 | @node GDB/MI Program Execution | |
23001 | @section @sc{gdb/mi} Program Execution | |
922fbb7b | 23002 | |
ef21caaf | 23003 | These are the asynchronous commands which generate the out-of-band |
3f94c067 | 23004 | record @samp{*stopped}. Currently @value{GDBN} only really executes |
ef21caaf NR |
23005 | asynchronously with remote targets and this interaction is mimicked in |
23006 | other cases. | |
922fbb7b | 23007 | |
922fbb7b AC |
23008 | @subheading The @code{-exec-continue} Command |
23009 | @findex -exec-continue | |
23010 | ||
23011 | @subsubheading Synopsis | |
23012 | ||
23013 | @smallexample | |
c3b108f7 | 23014 | -exec-continue [--all|--thread-group N] |
922fbb7b AC |
23015 | @end smallexample |
23016 | ||
ef21caaf | 23017 | Resumes the execution of the inferior program until a breakpoint is |
c3b108f7 VP |
23018 | encountered, or until the inferior exits. In all-stop mode |
23019 | (@pxref{All-Stop Mode}), may resume only one thread, or all threads, | |
23020 | depending on the value of the @samp{scheduler-locking} variable. In | |
23021 | non-stop mode (@pxref{Non-Stop Mode}), if the @samp{--all} is not | |
23022 | specified, only the thread specified with the @samp{--thread} option | |
23023 | (or current thread, if no @samp{--thread} is provided) is resumed. If | |
23024 | @samp{--all} is specified, all threads will be resumed. The | |
23025 | @samp{--all} option is ignored in all-stop mode. If the | |
23026 | @samp{--thread-group} options is specified, then all threads in that | |
23027 | thread group are resumed. | |
922fbb7b AC |
23028 | |
23029 | @subsubheading @value{GDBN} Command | |
23030 | ||
23031 | The corresponding @value{GDBN} corresponding is @samp{continue}. | |
23032 | ||
23033 | @subsubheading Example | |
23034 | ||
23035 | @smallexample | |
23036 | -exec-continue | |
23037 | ^running | |
594fe323 | 23038 | (gdb) |
922fbb7b | 23039 | @@Hello world |
a47ec5fe AR |
23040 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="2",frame=@{ |
23041 | func="foo",args=[],file="hello.c",fullname="/home/foo/bar/hello.c", | |
23042 | line="13"@} | |
594fe323 | 23043 | (gdb) |
922fbb7b AC |
23044 | @end smallexample |
23045 | ||
23046 | ||
23047 | @subheading The @code{-exec-finish} Command | |
23048 | @findex -exec-finish | |
23049 | ||
23050 | @subsubheading Synopsis | |
23051 | ||
23052 | @smallexample | |
23053 | -exec-finish | |
23054 | @end smallexample | |
23055 | ||
ef21caaf NR |
23056 | Resumes the execution of the inferior program until the current |
23057 | function is exited. Displays the results returned by the function. | |
922fbb7b AC |
23058 | |
23059 | @subsubheading @value{GDBN} Command | |
23060 | ||
23061 | The corresponding @value{GDBN} command is @samp{finish}. | |
23062 | ||
23063 | @subsubheading Example | |
23064 | ||
23065 | Function returning @code{void}. | |
23066 | ||
23067 | @smallexample | |
23068 | -exec-finish | |
23069 | ^running | |
594fe323 | 23070 | (gdb) |
922fbb7b AC |
23071 | @@hello from foo |
23072 | *stopped,reason="function-finished",frame=@{func="main",args=[], | |
948d5102 | 23073 | file="hello.c",fullname="/home/foo/bar/hello.c",line="7"@} |
594fe323 | 23074 | (gdb) |
922fbb7b AC |
23075 | @end smallexample |
23076 | ||
23077 | Function returning other than @code{void}. The name of the internal | |
23078 | @value{GDBN} variable storing the result is printed, together with the | |
23079 | value itself. | |
23080 | ||
23081 | @smallexample | |
23082 | -exec-finish | |
23083 | ^running | |
594fe323 | 23084 | (gdb) |
922fbb7b AC |
23085 | *stopped,reason="function-finished",frame=@{addr="0x000107b0",func="foo", |
23086 | args=[@{name="a",value="1"],@{name="b",value="9"@}@}, | |
948d5102 | 23087 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, |
922fbb7b | 23088 | gdb-result-var="$1",return-value="0" |
594fe323 | 23089 | (gdb) |
922fbb7b AC |
23090 | @end smallexample |
23091 | ||
23092 | ||
23093 | @subheading The @code{-exec-interrupt} Command | |
23094 | @findex -exec-interrupt | |
23095 | ||
23096 | @subsubheading Synopsis | |
23097 | ||
23098 | @smallexample | |
c3b108f7 | 23099 | -exec-interrupt [--all|--thread-group N] |
922fbb7b AC |
23100 | @end smallexample |
23101 | ||
ef21caaf NR |
23102 | Interrupts the background execution of the target. Note how the token |
23103 | associated with the stop message is the one for the execution command | |
23104 | that has been interrupted. The token for the interrupt itself only | |
23105 | appears in the @samp{^done} output. If the user is trying to | |
922fbb7b AC |
23106 | interrupt a non-running program, an error message will be printed. |
23107 | ||
c3b108f7 VP |
23108 | Note that when asynchronous execution is enabled, this command is |
23109 | asynchronous just like other execution commands. That is, first the | |
23110 | @samp{^done} response will be printed, and the target stop will be | |
23111 | reported after that using the @samp{*stopped} notification. | |
23112 | ||
23113 | In non-stop mode, only the context thread is interrupted by default. | |
23114 | All threads will be interrupted if the @samp{--all} option is | |
23115 | specified. If the @samp{--thread-group} option is specified, all | |
23116 | threads in that group will be interrupted. | |
23117 | ||
922fbb7b AC |
23118 | @subsubheading @value{GDBN} Command |
23119 | ||
23120 | The corresponding @value{GDBN} command is @samp{interrupt}. | |
23121 | ||
23122 | @subsubheading Example | |
23123 | ||
23124 | @smallexample | |
594fe323 | 23125 | (gdb) |
922fbb7b AC |
23126 | 111-exec-continue |
23127 | 111^running | |
23128 | ||
594fe323 | 23129 | (gdb) |
922fbb7b AC |
23130 | 222-exec-interrupt |
23131 | 222^done | |
594fe323 | 23132 | (gdb) |
922fbb7b | 23133 | 111*stopped,signal-name="SIGINT",signal-meaning="Interrupt", |
76ff342d | 23134 | frame=@{addr="0x00010140",func="foo",args=[],file="try.c", |
948d5102 | 23135 | fullname="/home/foo/bar/try.c",line="13"@} |
594fe323 | 23136 | (gdb) |
922fbb7b | 23137 | |
594fe323 | 23138 | (gdb) |
922fbb7b AC |
23139 | -exec-interrupt |
23140 | ^error,msg="mi_cmd_exec_interrupt: Inferior not executing." | |
594fe323 | 23141 | (gdb) |
922fbb7b AC |
23142 | @end smallexample |
23143 | ||
83eba9b7 VP |
23144 | @subheading The @code{-exec-jump} Command |
23145 | @findex -exec-jump | |
23146 | ||
23147 | @subsubheading Synopsis | |
23148 | ||
23149 | @smallexample | |
23150 | -exec-jump @var{location} | |
23151 | @end smallexample | |
23152 | ||
23153 | Resumes execution of the inferior program at the location specified by | |
23154 | parameter. @xref{Specify Location}, for a description of the | |
23155 | different forms of @var{location}. | |
23156 | ||
23157 | @subsubheading @value{GDBN} Command | |
23158 | ||
23159 | The corresponding @value{GDBN} command is @samp{jump}. | |
23160 | ||
23161 | @subsubheading Example | |
23162 | ||
23163 | @smallexample | |
23164 | -exec-jump foo.c:10 | |
23165 | *running,thread-id="all" | |
23166 | ^running | |
23167 | @end smallexample | |
23168 | ||
922fbb7b AC |
23169 | |
23170 | @subheading The @code{-exec-next} Command | |
23171 | @findex -exec-next | |
23172 | ||
23173 | @subsubheading Synopsis | |
23174 | ||
23175 | @smallexample | |
23176 | -exec-next | |
23177 | @end smallexample | |
23178 | ||
ef21caaf NR |
23179 | Resumes execution of the inferior program, stopping when the beginning |
23180 | of the next source line is reached. | |
922fbb7b AC |
23181 | |
23182 | @subsubheading @value{GDBN} Command | |
23183 | ||
23184 | The corresponding @value{GDBN} command is @samp{next}. | |
23185 | ||
23186 | @subsubheading Example | |
23187 | ||
23188 | @smallexample | |
23189 | -exec-next | |
23190 | ^running | |
594fe323 | 23191 | (gdb) |
922fbb7b | 23192 | *stopped,reason="end-stepping-range",line="8",file="hello.c" |
594fe323 | 23193 | (gdb) |
922fbb7b AC |
23194 | @end smallexample |
23195 | ||
23196 | ||
23197 | @subheading The @code{-exec-next-instruction} Command | |
23198 | @findex -exec-next-instruction | |
23199 | ||
23200 | @subsubheading Synopsis | |
23201 | ||
23202 | @smallexample | |
23203 | -exec-next-instruction | |
23204 | @end smallexample | |
23205 | ||
ef21caaf NR |
23206 | Executes one machine instruction. If the instruction is a function |
23207 | call, continues until the function returns. If the program stops at an | |
23208 | instruction in the middle of a source line, the address will be | |
23209 | printed as well. | |
922fbb7b AC |
23210 | |
23211 | @subsubheading @value{GDBN} Command | |
23212 | ||
23213 | The corresponding @value{GDBN} command is @samp{nexti}. | |
23214 | ||
23215 | @subsubheading Example | |
23216 | ||
23217 | @smallexample | |
594fe323 | 23218 | (gdb) |
922fbb7b AC |
23219 | -exec-next-instruction |
23220 | ^running | |
23221 | ||
594fe323 | 23222 | (gdb) |
922fbb7b AC |
23223 | *stopped,reason="end-stepping-range", |
23224 | addr="0x000100d4",line="5",file="hello.c" | |
594fe323 | 23225 | (gdb) |
922fbb7b AC |
23226 | @end smallexample |
23227 | ||
23228 | ||
23229 | @subheading The @code{-exec-return} Command | |
23230 | @findex -exec-return | |
23231 | ||
23232 | @subsubheading Synopsis | |
23233 | ||
23234 | @smallexample | |
23235 | -exec-return | |
23236 | @end smallexample | |
23237 | ||
23238 | Makes current function return immediately. Doesn't execute the inferior. | |
23239 | Displays the new current frame. | |
23240 | ||
23241 | @subsubheading @value{GDBN} Command | |
23242 | ||
23243 | The corresponding @value{GDBN} command is @samp{return}. | |
23244 | ||
23245 | @subsubheading Example | |
23246 | ||
23247 | @smallexample | |
594fe323 | 23248 | (gdb) |
922fbb7b AC |
23249 | 200-break-insert callee4 |
23250 | 200^done,bkpt=@{number="1",addr="0x00010734", | |
23251 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"@} | |
594fe323 | 23252 | (gdb) |
922fbb7b AC |
23253 | 000-exec-run |
23254 | 000^running | |
594fe323 | 23255 | (gdb) |
a47ec5fe | 23256 | 000*stopped,reason="breakpoint-hit",disp="keep",bkptno="1", |
922fbb7b | 23257 | frame=@{func="callee4",args=[], |
76ff342d DJ |
23258 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
23259 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@} | |
594fe323 | 23260 | (gdb) |
922fbb7b AC |
23261 | 205-break-delete |
23262 | 205^done | |
594fe323 | 23263 | (gdb) |
922fbb7b AC |
23264 | 111-exec-return |
23265 | 111^done,frame=@{level="0",func="callee3", | |
23266 | args=[@{name="strarg", | |
23267 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
23268 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
23269 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 23270 | (gdb) |
922fbb7b AC |
23271 | @end smallexample |
23272 | ||
23273 | ||
23274 | @subheading The @code{-exec-run} Command | |
23275 | @findex -exec-run | |
23276 | ||
23277 | @subsubheading Synopsis | |
23278 | ||
23279 | @smallexample | |
23280 | -exec-run | |
23281 | @end smallexample | |
23282 | ||
ef21caaf NR |
23283 | Starts execution of the inferior from the beginning. The inferior |
23284 | executes until either a breakpoint is encountered or the program | |
23285 | exits. In the latter case the output will include an exit code, if | |
23286 | the program has exited exceptionally. | |
922fbb7b AC |
23287 | |
23288 | @subsubheading @value{GDBN} Command | |
23289 | ||
23290 | The corresponding @value{GDBN} command is @samp{run}. | |
23291 | ||
ef21caaf | 23292 | @subsubheading Examples |
922fbb7b AC |
23293 | |
23294 | @smallexample | |
594fe323 | 23295 | (gdb) |
922fbb7b AC |
23296 | -break-insert main |
23297 | ^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c",line="4"@} | |
594fe323 | 23298 | (gdb) |
922fbb7b AC |
23299 | -exec-run |
23300 | ^running | |
594fe323 | 23301 | (gdb) |
a47ec5fe | 23302 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1", |
76ff342d | 23303 | frame=@{func="main",args=[],file="recursive2.c", |
948d5102 | 23304 | fullname="/home/foo/bar/recursive2.c",line="4"@} |
594fe323 | 23305 | (gdb) |
922fbb7b AC |
23306 | @end smallexample |
23307 | ||
ef21caaf NR |
23308 | @noindent |
23309 | Program exited normally: | |
23310 | ||
23311 | @smallexample | |
594fe323 | 23312 | (gdb) |
ef21caaf NR |
23313 | -exec-run |
23314 | ^running | |
594fe323 | 23315 | (gdb) |
ef21caaf NR |
23316 | x = 55 |
23317 | *stopped,reason="exited-normally" | |
594fe323 | 23318 | (gdb) |
ef21caaf NR |
23319 | @end smallexample |
23320 | ||
23321 | @noindent | |
23322 | Program exited exceptionally: | |
23323 | ||
23324 | @smallexample | |
594fe323 | 23325 | (gdb) |
ef21caaf NR |
23326 | -exec-run |
23327 | ^running | |
594fe323 | 23328 | (gdb) |
ef21caaf NR |
23329 | x = 55 |
23330 | *stopped,reason="exited",exit-code="01" | |
594fe323 | 23331 | (gdb) |
ef21caaf NR |
23332 | @end smallexample |
23333 | ||
23334 | Another way the program can terminate is if it receives a signal such as | |
23335 | @code{SIGINT}. In this case, @sc{gdb/mi} displays this: | |
23336 | ||
23337 | @smallexample | |
594fe323 | 23338 | (gdb) |
ef21caaf NR |
23339 | *stopped,reason="exited-signalled",signal-name="SIGINT", |
23340 | signal-meaning="Interrupt" | |
23341 | @end smallexample | |
23342 | ||
922fbb7b | 23343 | |
a2c02241 NR |
23344 | @c @subheading -exec-signal |
23345 | ||
23346 | ||
23347 | @subheading The @code{-exec-step} Command | |
23348 | @findex -exec-step | |
922fbb7b AC |
23349 | |
23350 | @subsubheading Synopsis | |
23351 | ||
23352 | @smallexample | |
a2c02241 | 23353 | -exec-step |
922fbb7b AC |
23354 | @end smallexample |
23355 | ||
a2c02241 NR |
23356 | Resumes execution of the inferior program, stopping when the beginning |
23357 | of the next source line is reached, if the next source line is not a | |
23358 | function call. If it is, stop at the first instruction of the called | |
23359 | function. | |
922fbb7b AC |
23360 | |
23361 | @subsubheading @value{GDBN} Command | |
23362 | ||
a2c02241 | 23363 | The corresponding @value{GDBN} command is @samp{step}. |
922fbb7b AC |
23364 | |
23365 | @subsubheading Example | |
23366 | ||
23367 | Stepping into a function: | |
23368 | ||
23369 | @smallexample | |
23370 | -exec-step | |
23371 | ^running | |
594fe323 | 23372 | (gdb) |
922fbb7b AC |
23373 | *stopped,reason="end-stepping-range", |
23374 | frame=@{func="foo",args=[@{name="a",value="10"@}, | |
76ff342d | 23375 | @{name="b",value="0"@}],file="recursive2.c", |
948d5102 | 23376 | fullname="/home/foo/bar/recursive2.c",line="11"@} |
594fe323 | 23377 | (gdb) |
922fbb7b AC |
23378 | @end smallexample |
23379 | ||
23380 | Regular stepping: | |
23381 | ||
23382 | @smallexample | |
23383 | -exec-step | |
23384 | ^running | |
594fe323 | 23385 | (gdb) |
922fbb7b | 23386 | *stopped,reason="end-stepping-range",line="14",file="recursive2.c" |
594fe323 | 23387 | (gdb) |
922fbb7b AC |
23388 | @end smallexample |
23389 | ||
23390 | ||
23391 | @subheading The @code{-exec-step-instruction} Command | |
23392 | @findex -exec-step-instruction | |
23393 | ||
23394 | @subsubheading Synopsis | |
23395 | ||
23396 | @smallexample | |
23397 | -exec-step-instruction | |
23398 | @end smallexample | |
23399 | ||
ef21caaf NR |
23400 | Resumes the inferior which executes one machine instruction. The |
23401 | output, once @value{GDBN} has stopped, will vary depending on whether | |
23402 | we have stopped in the middle of a source line or not. In the former | |
23403 | case, the address at which the program stopped will be printed as | |
922fbb7b AC |
23404 | well. |
23405 | ||
23406 | @subsubheading @value{GDBN} Command | |
23407 | ||
23408 | The corresponding @value{GDBN} command is @samp{stepi}. | |
23409 | ||
23410 | @subsubheading Example | |
23411 | ||
23412 | @smallexample | |
594fe323 | 23413 | (gdb) |
922fbb7b AC |
23414 | -exec-step-instruction |
23415 | ^running | |
23416 | ||
594fe323 | 23417 | (gdb) |
922fbb7b | 23418 | *stopped,reason="end-stepping-range", |
76ff342d | 23419 | frame=@{func="foo",args=[],file="try.c", |
948d5102 | 23420 | fullname="/home/foo/bar/try.c",line="10"@} |
594fe323 | 23421 | (gdb) |
922fbb7b AC |
23422 | -exec-step-instruction |
23423 | ^running | |
23424 | ||
594fe323 | 23425 | (gdb) |
922fbb7b | 23426 | *stopped,reason="end-stepping-range", |
76ff342d | 23427 | frame=@{addr="0x000100f4",func="foo",args=[],file="try.c", |
948d5102 | 23428 | fullname="/home/foo/bar/try.c",line="10"@} |
594fe323 | 23429 | (gdb) |
922fbb7b AC |
23430 | @end smallexample |
23431 | ||
23432 | ||
23433 | @subheading The @code{-exec-until} Command | |
23434 | @findex -exec-until | |
23435 | ||
23436 | @subsubheading Synopsis | |
23437 | ||
23438 | @smallexample | |
23439 | -exec-until [ @var{location} ] | |
23440 | @end smallexample | |
23441 | ||
ef21caaf NR |
23442 | Executes the inferior until the @var{location} specified in the |
23443 | argument is reached. If there is no argument, the inferior executes | |
23444 | until a source line greater than the current one is reached. The | |
23445 | reason for stopping in this case will be @samp{location-reached}. | |
922fbb7b AC |
23446 | |
23447 | @subsubheading @value{GDBN} Command | |
23448 | ||
23449 | The corresponding @value{GDBN} command is @samp{until}. | |
23450 | ||
23451 | @subsubheading Example | |
23452 | ||
23453 | @smallexample | |
594fe323 | 23454 | (gdb) |
922fbb7b AC |
23455 | -exec-until recursive2.c:6 |
23456 | ^running | |
594fe323 | 23457 | (gdb) |
922fbb7b AC |
23458 | x = 55 |
23459 | *stopped,reason="location-reached",frame=@{func="main",args=[], | |
948d5102 | 23460 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="6"@} |
594fe323 | 23461 | (gdb) |
922fbb7b AC |
23462 | @end smallexample |
23463 | ||
23464 | @ignore | |
23465 | @subheading -file-clear | |
23466 | Is this going away???? | |
23467 | @end ignore | |
23468 | ||
351ff01a | 23469 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
a2c02241 NR |
23470 | @node GDB/MI Stack Manipulation |
23471 | @section @sc{gdb/mi} Stack Manipulation Commands | |
351ff01a | 23472 | |
922fbb7b | 23473 | |
a2c02241 NR |
23474 | @subheading The @code{-stack-info-frame} Command |
23475 | @findex -stack-info-frame | |
922fbb7b AC |
23476 | |
23477 | @subsubheading Synopsis | |
23478 | ||
23479 | @smallexample | |
a2c02241 | 23480 | -stack-info-frame |
922fbb7b AC |
23481 | @end smallexample |
23482 | ||
a2c02241 | 23483 | Get info on the selected frame. |
922fbb7b AC |
23484 | |
23485 | @subsubheading @value{GDBN} Command | |
23486 | ||
a2c02241 NR |
23487 | The corresponding @value{GDBN} command is @samp{info frame} or @samp{frame} |
23488 | (without arguments). | |
922fbb7b AC |
23489 | |
23490 | @subsubheading Example | |
23491 | ||
23492 | @smallexample | |
594fe323 | 23493 | (gdb) |
a2c02241 NR |
23494 | -stack-info-frame |
23495 | ^done,frame=@{level="1",addr="0x0001076c",func="callee3", | |
23496 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23497 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@} | |
594fe323 | 23498 | (gdb) |
922fbb7b AC |
23499 | @end smallexample |
23500 | ||
a2c02241 NR |
23501 | @subheading The @code{-stack-info-depth} Command |
23502 | @findex -stack-info-depth | |
922fbb7b AC |
23503 | |
23504 | @subsubheading Synopsis | |
23505 | ||
23506 | @smallexample | |
a2c02241 | 23507 | -stack-info-depth [ @var{max-depth} ] |
922fbb7b AC |
23508 | @end smallexample |
23509 | ||
a2c02241 NR |
23510 | Return the depth of the stack. If the integer argument @var{max-depth} |
23511 | is specified, do not count beyond @var{max-depth} frames. | |
922fbb7b AC |
23512 | |
23513 | @subsubheading @value{GDBN} Command | |
23514 | ||
a2c02241 | 23515 | There's no equivalent @value{GDBN} command. |
922fbb7b AC |
23516 | |
23517 | @subsubheading Example | |
23518 | ||
a2c02241 NR |
23519 | For a stack with frame levels 0 through 11: |
23520 | ||
922fbb7b | 23521 | @smallexample |
594fe323 | 23522 | (gdb) |
a2c02241 NR |
23523 | -stack-info-depth |
23524 | ^done,depth="12" | |
594fe323 | 23525 | (gdb) |
a2c02241 NR |
23526 | -stack-info-depth 4 |
23527 | ^done,depth="4" | |
594fe323 | 23528 | (gdb) |
a2c02241 NR |
23529 | -stack-info-depth 12 |
23530 | ^done,depth="12" | |
594fe323 | 23531 | (gdb) |
a2c02241 NR |
23532 | -stack-info-depth 11 |
23533 | ^done,depth="11" | |
594fe323 | 23534 | (gdb) |
a2c02241 NR |
23535 | -stack-info-depth 13 |
23536 | ^done,depth="12" | |
594fe323 | 23537 | (gdb) |
922fbb7b AC |
23538 | @end smallexample |
23539 | ||
a2c02241 NR |
23540 | @subheading The @code{-stack-list-arguments} Command |
23541 | @findex -stack-list-arguments | |
922fbb7b AC |
23542 | |
23543 | @subsubheading Synopsis | |
23544 | ||
23545 | @smallexample | |
3afae151 | 23546 | -stack-list-arguments @var{print-values} |
a2c02241 | 23547 | [ @var{low-frame} @var{high-frame} ] |
922fbb7b AC |
23548 | @end smallexample |
23549 | ||
a2c02241 NR |
23550 | Display a list of the arguments for the frames between @var{low-frame} |
23551 | and @var{high-frame} (inclusive). If @var{low-frame} and | |
2f1acb09 VP |
23552 | @var{high-frame} are not provided, list the arguments for the whole |
23553 | call stack. If the two arguments are equal, show the single frame | |
23554 | at the corresponding level. It is an error if @var{low-frame} is | |
23555 | larger than the actual number of frames. On the other hand, | |
23556 | @var{high-frame} may be larger than the actual number of frames, in | |
23557 | which case only existing frames will be returned. | |
a2c02241 | 23558 | |
3afae151 VP |
23559 | If @var{print-values} is 0 or @code{--no-values}, print only the names of |
23560 | the variables; if it is 1 or @code{--all-values}, print also their | |
23561 | values; and if it is 2 or @code{--simple-values}, print the name, | |
23562 | type and value for simple data types, and the name and type for arrays, | |
23563 | structures and unions. | |
922fbb7b | 23564 | |
b3372f91 VP |
23565 | Use of this command to obtain arguments in a single frame is |
23566 | deprecated in favor of the @samp{-stack-list-variables} command. | |
23567 | ||
922fbb7b AC |
23568 | @subsubheading @value{GDBN} Command |
23569 | ||
a2c02241 NR |
23570 | @value{GDBN} does not have an equivalent command. @code{gdbtk} has a |
23571 | @samp{gdb_get_args} command which partially overlaps with the | |
23572 | functionality of @samp{-stack-list-arguments}. | |
922fbb7b AC |
23573 | |
23574 | @subsubheading Example | |
922fbb7b | 23575 | |
a2c02241 | 23576 | @smallexample |
594fe323 | 23577 | (gdb) |
a2c02241 NR |
23578 | -stack-list-frames |
23579 | ^done, | |
23580 | stack=[ | |
23581 | frame=@{level="0",addr="0x00010734",func="callee4", | |
23582 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23583 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@}, | |
23584 | frame=@{level="1",addr="0x0001076c",func="callee3", | |
23585 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23586 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@}, | |
23587 | frame=@{level="2",addr="0x0001078c",func="callee2", | |
23588 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23589 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="22"@}, | |
23590 | frame=@{level="3",addr="0x000107b4",func="callee1", | |
23591 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23592 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="27"@}, | |
23593 | frame=@{level="4",addr="0x000107e0",func="main", | |
23594 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23595 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="32"@}] | |
594fe323 | 23596 | (gdb) |
a2c02241 NR |
23597 | -stack-list-arguments 0 |
23598 | ^done, | |
23599 | stack-args=[ | |
23600 | frame=@{level="0",args=[]@}, | |
23601 | frame=@{level="1",args=[name="strarg"]@}, | |
23602 | frame=@{level="2",args=[name="intarg",name="strarg"]@}, | |
23603 | frame=@{level="3",args=[name="intarg",name="strarg",name="fltarg"]@}, | |
23604 | frame=@{level="4",args=[]@}] | |
594fe323 | 23605 | (gdb) |
a2c02241 NR |
23606 | -stack-list-arguments 1 |
23607 | ^done, | |
23608 | stack-args=[ | |
23609 | frame=@{level="0",args=[]@}, | |
23610 | frame=@{level="1", | |
23611 | args=[@{name="strarg",value="0x11940 \"A string argument.\""@}]@}, | |
23612 | frame=@{level="2",args=[ | |
23613 | @{name="intarg",value="2"@}, | |
23614 | @{name="strarg",value="0x11940 \"A string argument.\""@}]@}, | |
23615 | @{frame=@{level="3",args=[ | |
23616 | @{name="intarg",value="2"@}, | |
23617 | @{name="strarg",value="0x11940 \"A string argument.\""@}, | |
23618 | @{name="fltarg",value="3.5"@}]@}, | |
23619 | frame=@{level="4",args=[]@}] | |
594fe323 | 23620 | (gdb) |
a2c02241 NR |
23621 | -stack-list-arguments 0 2 2 |
23622 | ^done,stack-args=[frame=@{level="2",args=[name="intarg",name="strarg"]@}] | |
594fe323 | 23623 | (gdb) |
a2c02241 NR |
23624 | -stack-list-arguments 1 2 2 |
23625 | ^done,stack-args=[frame=@{level="2", | |
23626 | args=[@{name="intarg",value="2"@}, | |
23627 | @{name="strarg",value="0x11940 \"A string argument.\""@}]@}] | |
594fe323 | 23628 | (gdb) |
a2c02241 NR |
23629 | @end smallexample |
23630 | ||
23631 | @c @subheading -stack-list-exception-handlers | |
922fbb7b | 23632 | |
a2c02241 NR |
23633 | |
23634 | @subheading The @code{-stack-list-frames} Command | |
23635 | @findex -stack-list-frames | |
1abaf70c BR |
23636 | |
23637 | @subsubheading Synopsis | |
23638 | ||
23639 | @smallexample | |
a2c02241 | 23640 | -stack-list-frames [ @var{low-frame} @var{high-frame} ] |
1abaf70c BR |
23641 | @end smallexample |
23642 | ||
a2c02241 NR |
23643 | List the frames currently on the stack. For each frame it displays the |
23644 | following info: | |
23645 | ||
23646 | @table @samp | |
23647 | @item @var{level} | |
d3e8051b | 23648 | The frame number, 0 being the topmost frame, i.e., the innermost function. |
a2c02241 NR |
23649 | @item @var{addr} |
23650 | The @code{$pc} value for that frame. | |
23651 | @item @var{func} | |
23652 | Function name. | |
23653 | @item @var{file} | |
23654 | File name of the source file where the function lives. | |
23655 | @item @var{line} | |
23656 | Line number corresponding to the @code{$pc}. | |
23657 | @end table | |
23658 | ||
23659 | If invoked without arguments, this command prints a backtrace for the | |
23660 | whole stack. If given two integer arguments, it shows the frames whose | |
23661 | levels are between the two arguments (inclusive). If the two arguments | |
2ab1eb7a VP |
23662 | are equal, it shows the single frame at the corresponding level. It is |
23663 | an error if @var{low-frame} is larger than the actual number of | |
a5451f4e | 23664 | frames. On the other hand, @var{high-frame} may be larger than the |
2ab1eb7a | 23665 | actual number of frames, in which case only existing frames will be returned. |
1abaf70c BR |
23666 | |
23667 | @subsubheading @value{GDBN} Command | |
23668 | ||
a2c02241 | 23669 | The corresponding @value{GDBN} commands are @samp{backtrace} and @samp{where}. |
1abaf70c BR |
23670 | |
23671 | @subsubheading Example | |
23672 | ||
a2c02241 NR |
23673 | Full stack backtrace: |
23674 | ||
1abaf70c | 23675 | @smallexample |
594fe323 | 23676 | (gdb) |
a2c02241 NR |
23677 | -stack-list-frames |
23678 | ^done,stack= | |
23679 | [frame=@{level="0",addr="0x0001076c",func="foo", | |
23680 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="11"@}, | |
23681 | frame=@{level="1",addr="0x000107a4",func="foo", | |
23682 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23683 | frame=@{level="2",addr="0x000107a4",func="foo", | |
23684 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23685 | frame=@{level="3",addr="0x000107a4",func="foo", | |
23686 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23687 | frame=@{level="4",addr="0x000107a4",func="foo", | |
23688 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23689 | frame=@{level="5",addr="0x000107a4",func="foo", | |
23690 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23691 | frame=@{level="6",addr="0x000107a4",func="foo", | |
23692 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23693 | frame=@{level="7",addr="0x000107a4",func="foo", | |
23694 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23695 | frame=@{level="8",addr="0x000107a4",func="foo", | |
23696 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23697 | frame=@{level="9",addr="0x000107a4",func="foo", | |
23698 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23699 | frame=@{level="10",addr="0x000107a4",func="foo", | |
23700 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23701 | frame=@{level="11",addr="0x00010738",func="main", | |
23702 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="4"@}] | |
594fe323 | 23703 | (gdb) |
1abaf70c BR |
23704 | @end smallexample |
23705 | ||
a2c02241 | 23706 | Show frames between @var{low_frame} and @var{high_frame}: |
1abaf70c | 23707 | |
a2c02241 | 23708 | @smallexample |
594fe323 | 23709 | (gdb) |
a2c02241 NR |
23710 | -stack-list-frames 3 5 |
23711 | ^done,stack= | |
23712 | [frame=@{level="3",addr="0x000107a4",func="foo", | |
23713 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23714 | frame=@{level="4",addr="0x000107a4",func="foo", | |
23715 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23716 | frame=@{level="5",addr="0x000107a4",func="foo", | |
23717 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}] | |
594fe323 | 23718 | (gdb) |
a2c02241 | 23719 | @end smallexample |
922fbb7b | 23720 | |
a2c02241 | 23721 | Show a single frame: |
922fbb7b AC |
23722 | |
23723 | @smallexample | |
594fe323 | 23724 | (gdb) |
a2c02241 NR |
23725 | -stack-list-frames 3 3 |
23726 | ^done,stack= | |
23727 | [frame=@{level="3",addr="0x000107a4",func="foo", | |
23728 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}] | |
594fe323 | 23729 | (gdb) |
922fbb7b AC |
23730 | @end smallexample |
23731 | ||
922fbb7b | 23732 | |
a2c02241 NR |
23733 | @subheading The @code{-stack-list-locals} Command |
23734 | @findex -stack-list-locals | |
57c22c6c | 23735 | |
a2c02241 | 23736 | @subsubheading Synopsis |
922fbb7b AC |
23737 | |
23738 | @smallexample | |
a2c02241 | 23739 | -stack-list-locals @var{print-values} |
922fbb7b AC |
23740 | @end smallexample |
23741 | ||
a2c02241 NR |
23742 | Display the local variable names for the selected frame. If |
23743 | @var{print-values} is 0 or @code{--no-values}, print only the names of | |
23744 | the variables; if it is 1 or @code{--all-values}, print also their | |
23745 | values; and if it is 2 or @code{--simple-values}, print the name, | |
3afae151 | 23746 | type and value for simple data types, and the name and type for arrays, |
a2c02241 NR |
23747 | structures and unions. In this last case, a frontend can immediately |
23748 | display the value of simple data types and create variable objects for | |
d3e8051b | 23749 | other data types when the user wishes to explore their values in |
a2c02241 | 23750 | more detail. |
922fbb7b | 23751 | |
b3372f91 VP |
23752 | This command is deprecated in favor of the |
23753 | @samp{-stack-list-variables} command. | |
23754 | ||
922fbb7b AC |
23755 | @subsubheading @value{GDBN} Command |
23756 | ||
a2c02241 | 23757 | @samp{info locals} in @value{GDBN}, @samp{gdb_get_locals} in @code{gdbtk}. |
922fbb7b AC |
23758 | |
23759 | @subsubheading Example | |
922fbb7b AC |
23760 | |
23761 | @smallexample | |
594fe323 | 23762 | (gdb) |
a2c02241 NR |
23763 | -stack-list-locals 0 |
23764 | ^done,locals=[name="A",name="B",name="C"] | |
594fe323 | 23765 | (gdb) |
a2c02241 NR |
23766 | -stack-list-locals --all-values |
23767 | ^done,locals=[@{name="A",value="1"@},@{name="B",value="2"@}, | |
23768 | @{name="C",value="@{1, 2, 3@}"@}] | |
23769 | -stack-list-locals --simple-values | |
23770 | ^done,locals=[@{name="A",type="int",value="1"@}, | |
23771 | @{name="B",type="int",value="2"@},@{name="C",type="int [3]"@}] | |
594fe323 | 23772 | (gdb) |
922fbb7b AC |
23773 | @end smallexample |
23774 | ||
b3372f91 VP |
23775 | @subheading The @code{-stack-list-variables} Command |
23776 | @findex -stack-list-variables | |
23777 | ||
23778 | @subsubheading Synopsis | |
23779 | ||
23780 | @smallexample | |
23781 | -stack-list-variables @var{print-values} | |
23782 | @end smallexample | |
23783 | ||
23784 | Display the names of local variables and function arguments for the selected frame. If | |
23785 | @var{print-values} is 0 or @code{--no-values}, print only the names of | |
23786 | the variables; if it is 1 or @code{--all-values}, print also their | |
23787 | values; and if it is 2 or @code{--simple-values}, print the name, | |
3afae151 | 23788 | type and value for simple data types, and the name and type for arrays, |
b3372f91 VP |
23789 | structures and unions. |
23790 | ||
23791 | @subsubheading Example | |
23792 | ||
23793 | @smallexample | |
23794 | (gdb) | |
23795 | -stack-list-variables --thread 1 --frame 0 --all-values | |
4f412fd0 | 23796 | ^done,variables=[@{name="x",value="11"@},@{name="s",value="@{a = 1, b = 2@}"@}] |
b3372f91 VP |
23797 | (gdb) |
23798 | @end smallexample | |
23799 | ||
922fbb7b | 23800 | |
a2c02241 NR |
23801 | @subheading The @code{-stack-select-frame} Command |
23802 | @findex -stack-select-frame | |
922fbb7b AC |
23803 | |
23804 | @subsubheading Synopsis | |
23805 | ||
23806 | @smallexample | |
a2c02241 | 23807 | -stack-select-frame @var{framenum} |
922fbb7b AC |
23808 | @end smallexample |
23809 | ||
a2c02241 NR |
23810 | Change the selected frame. Select a different frame @var{framenum} on |
23811 | the stack. | |
922fbb7b | 23812 | |
c3b108f7 VP |
23813 | This command in deprecated in favor of passing the @samp{--frame} |
23814 | option to every command. | |
23815 | ||
922fbb7b AC |
23816 | @subsubheading @value{GDBN} Command |
23817 | ||
a2c02241 NR |
23818 | The corresponding @value{GDBN} commands are @samp{frame}, @samp{up}, |
23819 | @samp{down}, @samp{select-frame}, @samp{up-silent}, and @samp{down-silent}. | |
922fbb7b AC |
23820 | |
23821 | @subsubheading Example | |
23822 | ||
23823 | @smallexample | |
594fe323 | 23824 | (gdb) |
a2c02241 | 23825 | -stack-select-frame 2 |
922fbb7b | 23826 | ^done |
594fe323 | 23827 | (gdb) |
922fbb7b AC |
23828 | @end smallexample |
23829 | ||
23830 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
a2c02241 NR |
23831 | @node GDB/MI Variable Objects |
23832 | @section @sc{gdb/mi} Variable Objects | |
922fbb7b | 23833 | |
a1b5960f | 23834 | @ignore |
922fbb7b | 23835 | |
a2c02241 | 23836 | @subheading Motivation for Variable Objects in @sc{gdb/mi} |
922fbb7b | 23837 | |
a2c02241 NR |
23838 | For the implementation of a variable debugger window (locals, watched |
23839 | expressions, etc.), we are proposing the adaptation of the existing code | |
23840 | used by @code{Insight}. | |
922fbb7b | 23841 | |
a2c02241 | 23842 | The two main reasons for that are: |
922fbb7b | 23843 | |
a2c02241 NR |
23844 | @enumerate 1 |
23845 | @item | |
23846 | It has been proven in practice (it is already on its second generation). | |
922fbb7b | 23847 | |
a2c02241 NR |
23848 | @item |
23849 | It will shorten development time (needless to say how important it is | |
23850 | now). | |
23851 | @end enumerate | |
922fbb7b | 23852 | |
a2c02241 NR |
23853 | The original interface was designed to be used by Tcl code, so it was |
23854 | slightly changed so it could be used through @sc{gdb/mi}. This section | |
23855 | describes the @sc{gdb/mi} operations that will be available and gives some | |
23856 | hints about their use. | |
922fbb7b | 23857 | |
a2c02241 NR |
23858 | @emph{Note}: In addition to the set of operations described here, we |
23859 | expect the @sc{gui} implementation of a variable window to require, at | |
23860 | least, the following operations: | |
922fbb7b | 23861 | |
a2c02241 NR |
23862 | @itemize @bullet |
23863 | @item @code{-gdb-show} @code{output-radix} | |
23864 | @item @code{-stack-list-arguments} | |
23865 | @item @code{-stack-list-locals} | |
23866 | @item @code{-stack-select-frame} | |
23867 | @end itemize | |
922fbb7b | 23868 | |
a1b5960f VP |
23869 | @end ignore |
23870 | ||
c8b2f53c | 23871 | @subheading Introduction to Variable Objects |
922fbb7b | 23872 | |
a2c02241 | 23873 | @cindex variable objects in @sc{gdb/mi} |
c8b2f53c VP |
23874 | |
23875 | Variable objects are "object-oriented" MI interface for examining and | |
23876 | changing values of expressions. Unlike some other MI interfaces that | |
23877 | work with expressions, variable objects are specifically designed for | |
23878 | simple and efficient presentation in the frontend. A variable object | |
23879 | is identified by string name. When a variable object is created, the | |
23880 | frontend specifies the expression for that variable object. The | |
23881 | expression can be a simple variable, or it can be an arbitrary complex | |
23882 | expression, and can even involve CPU registers. After creating a | |
23883 | variable object, the frontend can invoke other variable object | |
23884 | operations---for example to obtain or change the value of a variable | |
23885 | object, or to change display format. | |
23886 | ||
23887 | Variable objects have hierarchical tree structure. Any variable object | |
23888 | that corresponds to a composite type, such as structure in C, has | |
23889 | a number of child variable objects, for example corresponding to each | |
23890 | element of a structure. A child variable object can itself have | |
23891 | children, recursively. Recursion ends when we reach | |
25d5ea92 VP |
23892 | leaf variable objects, which always have built-in types. Child variable |
23893 | objects are created only by explicit request, so if a frontend | |
23894 | is not interested in the children of a particular variable object, no | |
23895 | child will be created. | |
c8b2f53c VP |
23896 | |
23897 | For a leaf variable object it is possible to obtain its value as a | |
23898 | string, or set the value from a string. String value can be also | |
23899 | obtained for a non-leaf variable object, but it's generally a string | |
23900 | that only indicates the type of the object, and does not list its | |
23901 | contents. Assignment to a non-leaf variable object is not allowed. | |
23902 | ||
23903 | A frontend does not need to read the values of all variable objects each time | |
23904 | the program stops. Instead, MI provides an update command that lists all | |
23905 | variable objects whose values has changed since the last update | |
23906 | operation. This considerably reduces the amount of data that must | |
25d5ea92 VP |
23907 | be transferred to the frontend. As noted above, children variable |
23908 | objects are created on demand, and only leaf variable objects have a | |
23909 | real value. As result, gdb will read target memory only for leaf | |
23910 | variables that frontend has created. | |
23911 | ||
23912 | The automatic update is not always desirable. For example, a frontend | |
23913 | might want to keep a value of some expression for future reference, | |
23914 | and never update it. For another example, fetching memory is | |
23915 | relatively slow for embedded targets, so a frontend might want | |
23916 | to disable automatic update for the variables that are either not | |
23917 | visible on the screen, or ``closed''. This is possible using so | |
23918 | called ``frozen variable objects''. Such variable objects are never | |
23919 | implicitly updated. | |
922fbb7b | 23920 | |
c3b108f7 VP |
23921 | Variable objects can be either @dfn{fixed} or @dfn{floating}. For the |
23922 | fixed variable object, the expression is parsed when the variable | |
23923 | object is created, including associating identifiers to specific | |
23924 | variables. The meaning of expression never changes. For a floating | |
23925 | variable object the values of variables whose names appear in the | |
23926 | expressions are re-evaluated every time in the context of the current | |
23927 | frame. Consider this example: | |
23928 | ||
23929 | @smallexample | |
23930 | void do_work(...) | |
23931 | @{ | |
23932 | struct work_state state; | |
23933 | ||
23934 | if (...) | |
23935 | do_work(...); | |
23936 | @} | |
23937 | @end smallexample | |
23938 | ||
23939 | If a fixed variable object for the @code{state} variable is created in | |
23940 | this function, and we enter the recursive call, the the variable | |
23941 | object will report the value of @code{state} in the top-level | |
23942 | @code{do_work} invocation. On the other hand, a floating variable | |
23943 | object will report the value of @code{state} in the current frame. | |
23944 | ||
23945 | If an expression specified when creating a fixed variable object | |
23946 | refers to a local variable, the variable object becomes bound to the | |
23947 | thread and frame in which the variable object is created. When such | |
23948 | variable object is updated, @value{GDBN} makes sure that the | |
23949 | thread/frame combination the variable object is bound to still exists, | |
23950 | and re-evaluates the variable object in context of that thread/frame. | |
23951 | ||
a2c02241 NR |
23952 | The following is the complete set of @sc{gdb/mi} operations defined to |
23953 | access this functionality: | |
922fbb7b | 23954 | |
a2c02241 NR |
23955 | @multitable @columnfractions .4 .6 |
23956 | @item @strong{Operation} | |
23957 | @tab @strong{Description} | |
922fbb7b | 23958 | |
0cc7d26f TT |
23959 | @item @code{-enable-pretty-printing} |
23960 | @tab enable Python-based pretty-printing | |
a2c02241 NR |
23961 | @item @code{-var-create} |
23962 | @tab create a variable object | |
23963 | @item @code{-var-delete} | |
22d8a470 | 23964 | @tab delete the variable object and/or its children |
a2c02241 NR |
23965 | @item @code{-var-set-format} |
23966 | @tab set the display format of this variable | |
23967 | @item @code{-var-show-format} | |
23968 | @tab show the display format of this variable | |
23969 | @item @code{-var-info-num-children} | |
23970 | @tab tells how many children this object has | |
23971 | @item @code{-var-list-children} | |
23972 | @tab return a list of the object's children | |
23973 | @item @code{-var-info-type} | |
23974 | @tab show the type of this variable object | |
23975 | @item @code{-var-info-expression} | |
02142340 VP |
23976 | @tab print parent-relative expression that this variable object represents |
23977 | @item @code{-var-info-path-expression} | |
23978 | @tab print full expression that this variable object represents | |
a2c02241 NR |
23979 | @item @code{-var-show-attributes} |
23980 | @tab is this variable editable? does it exist here? | |
23981 | @item @code{-var-evaluate-expression} | |
23982 | @tab get the value of this variable | |
23983 | @item @code{-var-assign} | |
23984 | @tab set the value of this variable | |
23985 | @item @code{-var-update} | |
23986 | @tab update the variable and its children | |
25d5ea92 VP |
23987 | @item @code{-var-set-frozen} |
23988 | @tab set frozeness attribute | |
0cc7d26f TT |
23989 | @item @code{-var-set-update-range} |
23990 | @tab set range of children to display on update | |
a2c02241 | 23991 | @end multitable |
922fbb7b | 23992 | |
a2c02241 NR |
23993 | In the next subsection we describe each operation in detail and suggest |
23994 | how it can be used. | |
922fbb7b | 23995 | |
a2c02241 | 23996 | @subheading Description And Use of Operations on Variable Objects |
922fbb7b | 23997 | |
0cc7d26f TT |
23998 | @subheading The @code{-enable-pretty-printing} Command |
23999 | @findex -enable-pretty-printing | |
24000 | ||
24001 | @smallexample | |
24002 | -enable-pretty-printing | |
24003 | @end smallexample | |
24004 | ||
24005 | @value{GDBN} allows Python-based visualizers to affect the output of the | |
24006 | MI variable object commands. However, because there was no way to | |
24007 | implement this in a fully backward-compatible way, a front end must | |
24008 | request that this functionality be enabled. | |
24009 | ||
24010 | Once enabled, this feature cannot be disabled. | |
24011 | ||
24012 | Note that if Python support has not been compiled into @value{GDBN}, | |
24013 | this command will still succeed (and do nothing). | |
24014 | ||
f43030c4 TT |
24015 | This feature is currently (as of @value{GDBN} 7.0) experimental, and |
24016 | may work differently in future versions of @value{GDBN}. | |
24017 | ||
a2c02241 NR |
24018 | @subheading The @code{-var-create} Command |
24019 | @findex -var-create | |
ef21caaf | 24020 | |
a2c02241 | 24021 | @subsubheading Synopsis |
ef21caaf | 24022 | |
a2c02241 NR |
24023 | @smallexample |
24024 | -var-create @{@var{name} | "-"@} | |
c3b108f7 | 24025 | @{@var{frame-addr} | "*" | "@@"@} @var{expression} |
a2c02241 NR |
24026 | @end smallexample |
24027 | ||
24028 | This operation creates a variable object, which allows the monitoring of | |
24029 | a variable, the result of an expression, a memory cell or a CPU | |
24030 | register. | |
ef21caaf | 24031 | |
a2c02241 NR |
24032 | The @var{name} parameter is the string by which the object can be |
24033 | referenced. It must be unique. If @samp{-} is specified, the varobj | |
24034 | system will generate a string ``varNNNNNN'' automatically. It will be | |
c3b108f7 | 24035 | unique provided that one does not specify @var{name} of that format. |
a2c02241 | 24036 | The command fails if a duplicate name is found. |
ef21caaf | 24037 | |
a2c02241 NR |
24038 | The frame under which the expression should be evaluated can be |
24039 | specified by @var{frame-addr}. A @samp{*} indicates that the current | |
c3b108f7 VP |
24040 | frame should be used. A @samp{@@} indicates that a floating variable |
24041 | object must be created. | |
922fbb7b | 24042 | |
a2c02241 NR |
24043 | @var{expression} is any expression valid on the current language set (must not |
24044 | begin with a @samp{*}), or one of the following: | |
922fbb7b | 24045 | |
a2c02241 NR |
24046 | @itemize @bullet |
24047 | @item | |
24048 | @samp{*@var{addr}}, where @var{addr} is the address of a memory cell | |
922fbb7b | 24049 | |
a2c02241 NR |
24050 | @item |
24051 | @samp{*@var{addr}-@var{addr}} --- a memory address range (TBD) | |
922fbb7b | 24052 | |
a2c02241 NR |
24053 | @item |
24054 | @samp{$@var{regname}} --- a CPU register name | |
24055 | @end itemize | |
922fbb7b | 24056 | |
0cc7d26f TT |
24057 | @cindex dynamic varobj |
24058 | A varobj's contents may be provided by a Python-based pretty-printer. In this | |
24059 | case the varobj is known as a @dfn{dynamic varobj}. Dynamic varobjs | |
24060 | have slightly different semantics in some cases. If the | |
24061 | @code{-enable-pretty-printing} command is not sent, then @value{GDBN} | |
24062 | will never create a dynamic varobj. This ensures backward | |
24063 | compatibility for existing clients. | |
24064 | ||
a2c02241 | 24065 | @subsubheading Result |
922fbb7b | 24066 | |
0cc7d26f TT |
24067 | This operation returns attributes of the newly-created varobj. These |
24068 | are: | |
24069 | ||
24070 | @table @samp | |
24071 | @item name | |
24072 | The name of the varobj. | |
24073 | ||
24074 | @item numchild | |
24075 | The number of children of the varobj. This number is not necessarily | |
24076 | reliable for a dynamic varobj. Instead, you must examine the | |
24077 | @samp{has_more} attribute. | |
24078 | ||
24079 | @item value | |
24080 | The varobj's scalar value. For a varobj whose type is some sort of | |
24081 | aggregate (e.g., a @code{struct}), or for a dynamic varobj, this value | |
24082 | will not be interesting. | |
24083 | ||
24084 | @item type | |
24085 | The varobj's type. This is a string representation of the type, as | |
24086 | would be printed by the @value{GDBN} CLI. | |
24087 | ||
24088 | @item thread-id | |
24089 | If a variable object is bound to a specific thread, then this is the | |
24090 | thread's identifier. | |
24091 | ||
24092 | @item has_more | |
24093 | For a dynamic varobj, this indicates whether there appear to be any | |
24094 | children available. For a non-dynamic varobj, this will be 0. | |
24095 | ||
24096 | @item dynamic | |
24097 | This attribute will be present and have the value @samp{1} if the | |
24098 | varobj is a dynamic varobj. If the varobj is not a dynamic varobj, | |
24099 | then this attribute will not be present. | |
24100 | ||
24101 | @item displayhint | |
24102 | A dynamic varobj can supply a display hint to the front end. The | |
24103 | value comes directly from the Python pretty-printer object's | |
24104 | @code{display_hint} method. @xref{Pretty Printing}. | |
24105 | @end table | |
24106 | ||
24107 | Typical output will look like this: | |
922fbb7b AC |
24108 | |
24109 | @smallexample | |
0cc7d26f TT |
24110 | name="@var{name}",numchild="@var{N}",type="@var{type}",thread-id="@var{M}", |
24111 | has_more="@var{has_more}" | |
dcaaae04 NR |
24112 | @end smallexample |
24113 | ||
a2c02241 NR |
24114 | |
24115 | @subheading The @code{-var-delete} Command | |
24116 | @findex -var-delete | |
922fbb7b AC |
24117 | |
24118 | @subsubheading Synopsis | |
24119 | ||
24120 | @smallexample | |
22d8a470 | 24121 | -var-delete [ -c ] @var{name} |
922fbb7b AC |
24122 | @end smallexample |
24123 | ||
a2c02241 | 24124 | Deletes a previously created variable object and all of its children. |
22d8a470 | 24125 | With the @samp{-c} option, just deletes the children. |
922fbb7b | 24126 | |
a2c02241 | 24127 | Returns an error if the object @var{name} is not found. |
922fbb7b | 24128 | |
922fbb7b | 24129 | |
a2c02241 NR |
24130 | @subheading The @code{-var-set-format} Command |
24131 | @findex -var-set-format | |
922fbb7b | 24132 | |
a2c02241 | 24133 | @subsubheading Synopsis |
922fbb7b AC |
24134 | |
24135 | @smallexample | |
a2c02241 | 24136 | -var-set-format @var{name} @var{format-spec} |
922fbb7b AC |
24137 | @end smallexample |
24138 | ||
a2c02241 NR |
24139 | Sets the output format for the value of the object @var{name} to be |
24140 | @var{format-spec}. | |
24141 | ||
de051565 | 24142 | @anchor{-var-set-format} |
a2c02241 NR |
24143 | The syntax for the @var{format-spec} is as follows: |
24144 | ||
24145 | @smallexample | |
24146 | @var{format-spec} @expansion{} | |
24147 | @{binary | decimal | hexadecimal | octal | natural@} | |
24148 | @end smallexample | |
24149 | ||
c8b2f53c VP |
24150 | The natural format is the default format choosen automatically |
24151 | based on the variable type (like decimal for an @code{int}, hex | |
24152 | for pointers, etc.). | |
24153 | ||
24154 | For a variable with children, the format is set only on the | |
24155 | variable itself, and the children are not affected. | |
a2c02241 NR |
24156 | |
24157 | @subheading The @code{-var-show-format} Command | |
24158 | @findex -var-show-format | |
922fbb7b AC |
24159 | |
24160 | @subsubheading Synopsis | |
24161 | ||
24162 | @smallexample | |
a2c02241 | 24163 | -var-show-format @var{name} |
922fbb7b AC |
24164 | @end smallexample |
24165 | ||
a2c02241 | 24166 | Returns the format used to display the value of the object @var{name}. |
922fbb7b | 24167 | |
a2c02241 NR |
24168 | @smallexample |
24169 | @var{format} @expansion{} | |
24170 | @var{format-spec} | |
24171 | @end smallexample | |
922fbb7b | 24172 | |
922fbb7b | 24173 | |
a2c02241 NR |
24174 | @subheading The @code{-var-info-num-children} Command |
24175 | @findex -var-info-num-children | |
24176 | ||
24177 | @subsubheading Synopsis | |
24178 | ||
24179 | @smallexample | |
24180 | -var-info-num-children @var{name} | |
24181 | @end smallexample | |
24182 | ||
24183 | Returns the number of children of a variable object @var{name}: | |
24184 | ||
24185 | @smallexample | |
24186 | numchild=@var{n} | |
24187 | @end smallexample | |
24188 | ||
0cc7d26f TT |
24189 | Note that this number is not completely reliable for a dynamic varobj. |
24190 | It will return the current number of children, but more children may | |
24191 | be available. | |
24192 | ||
a2c02241 NR |
24193 | |
24194 | @subheading The @code{-var-list-children} Command | |
24195 | @findex -var-list-children | |
24196 | ||
24197 | @subsubheading Synopsis | |
24198 | ||
24199 | @smallexample | |
0cc7d26f | 24200 | -var-list-children [@var{print-values}] @var{name} [@var{from} @var{to}] |
a2c02241 | 24201 | @end smallexample |
b569d230 | 24202 | @anchor{-var-list-children} |
a2c02241 NR |
24203 | |
24204 | Return a list of the children of the specified variable object and | |
24205 | create variable objects for them, if they do not already exist. With | |
24206 | a single argument or if @var{print-values} has a value for of 0 or | |
24207 | @code{--no-values}, print only the names of the variables; if | |
24208 | @var{print-values} is 1 or @code{--all-values}, also print their | |
24209 | values; and if it is 2 or @code{--simple-values} print the name and | |
24210 | value for simple data types and just the name for arrays, structures | |
24211 | and unions. | |
922fbb7b | 24212 | |
0cc7d26f TT |
24213 | @var{from} and @var{to}, if specified, indicate the range of children |
24214 | to report. If @var{from} or @var{to} is less than zero, the range is | |
24215 | reset and all children will be reported. Otherwise, children starting | |
24216 | at @var{from} (zero-based) and up to and excluding @var{to} will be | |
24217 | reported. | |
24218 | ||
24219 | If a child range is requested, it will only affect the current call to | |
24220 | @code{-var-list-children}, but not future calls to @code{-var-update}. | |
24221 | For this, you must instead use @code{-var-set-update-range}. The | |
24222 | intent of this approach is to enable a front end to implement any | |
24223 | update approach it likes; for example, scrolling a view may cause the | |
24224 | front end to request more children with @code{-var-list-children}, and | |
24225 | then the front end could call @code{-var-set-update-range} with a | |
24226 | different range to ensure that future updates are restricted to just | |
24227 | the visible items. | |
24228 | ||
b569d230 EZ |
24229 | For each child the following results are returned: |
24230 | ||
24231 | @table @var | |
24232 | ||
24233 | @item name | |
24234 | Name of the variable object created for this child. | |
24235 | ||
24236 | @item exp | |
24237 | The expression to be shown to the user by the front end to designate this child. | |
24238 | For example this may be the name of a structure member. | |
24239 | ||
0cc7d26f TT |
24240 | For a dynamic varobj, this value cannot be used to form an |
24241 | expression. There is no way to do this at all with a dynamic varobj. | |
24242 | ||
b569d230 EZ |
24243 | For C/C@t{++} structures there are several pseudo children returned to |
24244 | designate access qualifiers. For these pseudo children @var{exp} is | |
24245 | @samp{public}, @samp{private}, or @samp{protected}. In this case the | |
24246 | type and value are not present. | |
24247 | ||
0cc7d26f TT |
24248 | A dynamic varobj will not report the access qualifying |
24249 | pseudo-children, regardless of the language. This information is not | |
24250 | available at all with a dynamic varobj. | |
24251 | ||
b569d230 | 24252 | @item numchild |
0cc7d26f TT |
24253 | Number of children this child has. For a dynamic varobj, this will be |
24254 | 0. | |
b569d230 EZ |
24255 | |
24256 | @item type | |
24257 | The type of the child. | |
24258 | ||
24259 | @item value | |
24260 | If values were requested, this is the value. | |
24261 | ||
24262 | @item thread-id | |
24263 | If this variable object is associated with a thread, this is the thread id. | |
24264 | Otherwise this result is not present. | |
24265 | ||
24266 | @item frozen | |
24267 | If the variable object is frozen, this variable will be present with a value of 1. | |
24268 | @end table | |
24269 | ||
0cc7d26f TT |
24270 | The result may have its own attributes: |
24271 | ||
24272 | @table @samp | |
24273 | @item displayhint | |
24274 | A dynamic varobj can supply a display hint to the front end. The | |
24275 | value comes directly from the Python pretty-printer object's | |
24276 | @code{display_hint} method. @xref{Pretty Printing}. | |
24277 | ||
24278 | @item has_more | |
24279 | This is an integer attribute which is nonzero if there are children | |
24280 | remaining after the end of the selected range. | |
24281 | @end table | |
24282 | ||
922fbb7b AC |
24283 | @subsubheading Example |
24284 | ||
24285 | @smallexample | |
594fe323 | 24286 | (gdb) |
a2c02241 | 24287 | -var-list-children n |
b569d230 | 24288 | ^done,numchild=@var{n},children=[child=@{name=@var{name},exp=@var{exp}, |
a2c02241 | 24289 | numchild=@var{n},type=@var{type}@},@r{(repeats N times)}] |
594fe323 | 24290 | (gdb) |
a2c02241 | 24291 | -var-list-children --all-values n |
b569d230 | 24292 | ^done,numchild=@var{n},children=[child=@{name=@var{name},exp=@var{exp}, |
a2c02241 | 24293 | numchild=@var{n},value=@var{value},type=@var{type}@},@r{(repeats N times)}] |
922fbb7b AC |
24294 | @end smallexample |
24295 | ||
922fbb7b | 24296 | |
a2c02241 NR |
24297 | @subheading The @code{-var-info-type} Command |
24298 | @findex -var-info-type | |
922fbb7b | 24299 | |
a2c02241 NR |
24300 | @subsubheading Synopsis |
24301 | ||
24302 | @smallexample | |
24303 | -var-info-type @var{name} | |
24304 | @end smallexample | |
24305 | ||
24306 | Returns the type of the specified variable @var{name}. The type is | |
24307 | returned as a string in the same format as it is output by the | |
24308 | @value{GDBN} CLI: | |
24309 | ||
24310 | @smallexample | |
24311 | type=@var{typename} | |
24312 | @end smallexample | |
24313 | ||
24314 | ||
24315 | @subheading The @code{-var-info-expression} Command | |
24316 | @findex -var-info-expression | |
922fbb7b AC |
24317 | |
24318 | @subsubheading Synopsis | |
24319 | ||
24320 | @smallexample | |
a2c02241 | 24321 | -var-info-expression @var{name} |
922fbb7b AC |
24322 | @end smallexample |
24323 | ||
02142340 VP |
24324 | Returns a string that is suitable for presenting this |
24325 | variable object in user interface. The string is generally | |
24326 | not valid expression in the current language, and cannot be evaluated. | |
24327 | ||
24328 | For example, if @code{a} is an array, and variable object | |
24329 | @code{A} was created for @code{a}, then we'll get this output: | |
922fbb7b | 24330 | |
a2c02241 | 24331 | @smallexample |
02142340 VP |
24332 | (gdb) -var-info-expression A.1 |
24333 | ^done,lang="C",exp="1" | |
a2c02241 | 24334 | @end smallexample |
922fbb7b | 24335 | |
a2c02241 | 24336 | @noindent |
02142340 VP |
24337 | Here, the values of @code{lang} can be @code{@{"C" | "C++" | "Java"@}}. |
24338 | ||
24339 | Note that the output of the @code{-var-list-children} command also | |
24340 | includes those expressions, so the @code{-var-info-expression} command | |
24341 | is of limited use. | |
24342 | ||
24343 | @subheading The @code{-var-info-path-expression} Command | |
24344 | @findex -var-info-path-expression | |
24345 | ||
24346 | @subsubheading Synopsis | |
24347 | ||
24348 | @smallexample | |
24349 | -var-info-path-expression @var{name} | |
24350 | @end smallexample | |
24351 | ||
24352 | Returns an expression that can be evaluated in the current | |
24353 | context and will yield the same value that a variable object has. | |
24354 | Compare this with the @code{-var-info-expression} command, which | |
24355 | result can be used only for UI presentation. Typical use of | |
24356 | the @code{-var-info-path-expression} command is creating a | |
24357 | watchpoint from a variable object. | |
24358 | ||
0cc7d26f TT |
24359 | This command is currently not valid for children of a dynamic varobj, |
24360 | and will give an error when invoked on one. | |
24361 | ||
02142340 VP |
24362 | For example, suppose @code{C} is a C@t{++} class, derived from class |
24363 | @code{Base}, and that the @code{Base} class has a member called | |
24364 | @code{m_size}. Assume a variable @code{c} is has the type of | |
24365 | @code{C} and a variable object @code{C} was created for variable | |
24366 | @code{c}. Then, we'll get this output: | |
24367 | @smallexample | |
24368 | (gdb) -var-info-path-expression C.Base.public.m_size | |
24369 | ^done,path_expr=((Base)c).m_size) | |
24370 | @end smallexample | |
922fbb7b | 24371 | |
a2c02241 NR |
24372 | @subheading The @code{-var-show-attributes} Command |
24373 | @findex -var-show-attributes | |
922fbb7b | 24374 | |
a2c02241 | 24375 | @subsubheading Synopsis |
922fbb7b | 24376 | |
a2c02241 NR |
24377 | @smallexample |
24378 | -var-show-attributes @var{name} | |
24379 | @end smallexample | |
922fbb7b | 24380 | |
a2c02241 | 24381 | List attributes of the specified variable object @var{name}: |
922fbb7b AC |
24382 | |
24383 | @smallexample | |
a2c02241 | 24384 | status=@var{attr} [ ( ,@var{attr} )* ] |
922fbb7b AC |
24385 | @end smallexample |
24386 | ||
a2c02241 NR |
24387 | @noindent |
24388 | where @var{attr} is @code{@{ @{ editable | noneditable @} | TBD @}}. | |
24389 | ||
24390 | @subheading The @code{-var-evaluate-expression} Command | |
24391 | @findex -var-evaluate-expression | |
24392 | ||
24393 | @subsubheading Synopsis | |
24394 | ||
24395 | @smallexample | |
de051565 | 24396 | -var-evaluate-expression [-f @var{format-spec}] @var{name} |
a2c02241 NR |
24397 | @end smallexample |
24398 | ||
24399 | Evaluates the expression that is represented by the specified variable | |
de051565 MK |
24400 | object and returns its value as a string. The format of the string |
24401 | can be specified with the @samp{-f} option. The possible values of | |
24402 | this option are the same as for @code{-var-set-format} | |
24403 | (@pxref{-var-set-format}). If the @samp{-f} option is not specified, | |
24404 | the current display format will be used. The current display format | |
24405 | can be changed using the @code{-var-set-format} command. | |
a2c02241 NR |
24406 | |
24407 | @smallexample | |
24408 | value=@var{value} | |
24409 | @end smallexample | |
24410 | ||
24411 | Note that one must invoke @code{-var-list-children} for a variable | |
24412 | before the value of a child variable can be evaluated. | |
24413 | ||
24414 | @subheading The @code{-var-assign} Command | |
24415 | @findex -var-assign | |
24416 | ||
24417 | @subsubheading Synopsis | |
24418 | ||
24419 | @smallexample | |
24420 | -var-assign @var{name} @var{expression} | |
24421 | @end smallexample | |
24422 | ||
24423 | Assigns the value of @var{expression} to the variable object specified | |
24424 | by @var{name}. The object must be @samp{editable}. If the variable's | |
24425 | value is altered by the assign, the variable will show up in any | |
24426 | subsequent @code{-var-update} list. | |
24427 | ||
24428 | @subsubheading Example | |
922fbb7b AC |
24429 | |
24430 | @smallexample | |
594fe323 | 24431 | (gdb) |
a2c02241 NR |
24432 | -var-assign var1 3 |
24433 | ^done,value="3" | |
594fe323 | 24434 | (gdb) |
a2c02241 NR |
24435 | -var-update * |
24436 | ^done,changelist=[@{name="var1",in_scope="true",type_changed="false"@}] | |
594fe323 | 24437 | (gdb) |
922fbb7b AC |
24438 | @end smallexample |
24439 | ||
a2c02241 NR |
24440 | @subheading The @code{-var-update} Command |
24441 | @findex -var-update | |
24442 | ||
24443 | @subsubheading Synopsis | |
24444 | ||
24445 | @smallexample | |
24446 | -var-update [@var{print-values}] @{@var{name} | "*"@} | |
24447 | @end smallexample | |
24448 | ||
c8b2f53c VP |
24449 | Reevaluate the expressions corresponding to the variable object |
24450 | @var{name} and all its direct and indirect children, and return the | |
36ece8b3 NR |
24451 | list of variable objects whose values have changed; @var{name} must |
24452 | be a root variable object. Here, ``changed'' means that the result of | |
24453 | @code{-var-evaluate-expression} before and after the | |
24454 | @code{-var-update} is different. If @samp{*} is used as the variable | |
9f708cb2 VP |
24455 | object names, all existing variable objects are updated, except |
24456 | for frozen ones (@pxref{-var-set-frozen}). The option | |
36ece8b3 | 24457 | @var{print-values} determines whether both names and values, or just |
de051565 | 24458 | names are printed. The possible values of this option are the same |
36ece8b3 NR |
24459 | as for @code{-var-list-children} (@pxref{-var-list-children}). It is |
24460 | recommended to use the @samp{--all-values} option, to reduce the | |
24461 | number of MI commands needed on each program stop. | |
c8b2f53c | 24462 | |
c3b108f7 VP |
24463 | With the @samp{*} parameter, if a variable object is bound to a |
24464 | currently running thread, it will not be updated, without any | |
24465 | diagnostic. | |
a2c02241 | 24466 | |
0cc7d26f TT |
24467 | If @code{-var-set-update-range} was previously used on a varobj, then |
24468 | only the selected range of children will be reported. | |
922fbb7b | 24469 | |
0cc7d26f TT |
24470 | @code{-var-update} reports all the changed varobjs in a tuple named |
24471 | @samp{changelist}. | |
24472 | ||
24473 | Each item in the change list is itself a tuple holding: | |
24474 | ||
24475 | @table @samp | |
24476 | @item name | |
24477 | The name of the varobj. | |
24478 | ||
24479 | @item value | |
24480 | If values were requested for this update, then this field will be | |
24481 | present and will hold the value of the varobj. | |
922fbb7b | 24482 | |
0cc7d26f | 24483 | @item in_scope |
9f708cb2 | 24484 | @anchor{-var-update} |
0cc7d26f | 24485 | This field is a string which may take one of three values: |
36ece8b3 NR |
24486 | |
24487 | @table @code | |
24488 | @item "true" | |
24489 | The variable object's current value is valid. | |
24490 | ||
24491 | @item "false" | |
24492 | The variable object does not currently hold a valid value but it may | |
24493 | hold one in the future if its associated expression comes back into | |
24494 | scope. | |
24495 | ||
24496 | @item "invalid" | |
24497 | The variable object no longer holds a valid value. | |
24498 | This can occur when the executable file being debugged has changed, | |
24499 | either through recompilation or by using the @value{GDBN} @code{file} | |
24500 | command. The front end should normally choose to delete these variable | |
24501 | objects. | |
24502 | @end table | |
24503 | ||
24504 | In the future new values may be added to this list so the front should | |
24505 | be prepared for this possibility. @xref{GDB/MI Development and Front Ends, ,@sc{GDB/MI} Development and Front Ends}. | |
24506 | ||
0cc7d26f TT |
24507 | @item type_changed |
24508 | This is only present if the varobj is still valid. If the type | |
24509 | changed, then this will be the string @samp{true}; otherwise it will | |
24510 | be @samp{false}. | |
24511 | ||
24512 | @item new_type | |
24513 | If the varobj's type changed, then this field will be present and will | |
24514 | hold the new type. | |
24515 | ||
24516 | @item new_num_children | |
24517 | For a dynamic varobj, if the number of children changed, or if the | |
24518 | type changed, this will be the new number of children. | |
24519 | ||
24520 | The @samp{numchild} field in other varobj responses is generally not | |
24521 | valid for a dynamic varobj -- it will show the number of children that | |
24522 | @value{GDBN} knows about, but because dynamic varobjs lazily | |
24523 | instantiate their children, this will not reflect the number of | |
24524 | children which may be available. | |
24525 | ||
24526 | The @samp{new_num_children} attribute only reports changes to the | |
24527 | number of children known by @value{GDBN}. This is the only way to | |
24528 | detect whether an update has removed children (which necessarily can | |
24529 | only happen at the end of the update range). | |
24530 | ||
24531 | @item displayhint | |
24532 | The display hint, if any. | |
24533 | ||
24534 | @item has_more | |
24535 | This is an integer value, which will be 1 if there are more children | |
24536 | available outside the varobj's update range. | |
24537 | ||
24538 | @item dynamic | |
24539 | This attribute will be present and have the value @samp{1} if the | |
24540 | varobj is a dynamic varobj. If the varobj is not a dynamic varobj, | |
24541 | then this attribute will not be present. | |
24542 | ||
24543 | @item new_children | |
24544 | If new children were added to a dynamic varobj within the selected | |
24545 | update range (as set by @code{-var-set-update-range}), then they will | |
24546 | be listed in this attribute. | |
24547 | @end table | |
24548 | ||
24549 | @subsubheading Example | |
24550 | ||
24551 | @smallexample | |
24552 | (gdb) | |
24553 | -var-assign var1 3 | |
24554 | ^done,value="3" | |
24555 | (gdb) | |
24556 | -var-update --all-values var1 | |
24557 | ^done,changelist=[@{name="var1",value="3",in_scope="true", | |
24558 | type_changed="false"@}] | |
24559 | (gdb) | |
24560 | @end smallexample | |
24561 | ||
25d5ea92 VP |
24562 | @subheading The @code{-var-set-frozen} Command |
24563 | @findex -var-set-frozen | |
9f708cb2 | 24564 | @anchor{-var-set-frozen} |
25d5ea92 VP |
24565 | |
24566 | @subsubheading Synopsis | |
24567 | ||
24568 | @smallexample | |
9f708cb2 | 24569 | -var-set-frozen @var{name} @var{flag} |
25d5ea92 VP |
24570 | @end smallexample |
24571 | ||
9f708cb2 | 24572 | Set the frozenness flag on the variable object @var{name}. The |
25d5ea92 | 24573 | @var{flag} parameter should be either @samp{1} to make the variable |
9f708cb2 | 24574 | frozen or @samp{0} to make it unfrozen. If a variable object is |
25d5ea92 | 24575 | frozen, then neither itself, nor any of its children, are |
9f708cb2 | 24576 | implicitly updated by @code{-var-update} of |
25d5ea92 VP |
24577 | a parent variable or by @code{-var-update *}. Only |
24578 | @code{-var-update} of the variable itself will update its value and | |
24579 | values of its children. After a variable object is unfrozen, it is | |
24580 | implicitly updated by all subsequent @code{-var-update} operations. | |
24581 | Unfreezing a variable does not update it, only subsequent | |
24582 | @code{-var-update} does. | |
24583 | ||
24584 | @subsubheading Example | |
24585 | ||
24586 | @smallexample | |
24587 | (gdb) | |
24588 | -var-set-frozen V 1 | |
24589 | ^done | |
24590 | (gdb) | |
24591 | @end smallexample | |
24592 | ||
0cc7d26f TT |
24593 | @subheading The @code{-var-set-update-range} command |
24594 | @findex -var-set-update-range | |
24595 | @anchor{-var-set-update-range} | |
24596 | ||
24597 | @subsubheading Synopsis | |
24598 | ||
24599 | @smallexample | |
24600 | -var-set-update-range @var{name} @var{from} @var{to} | |
24601 | @end smallexample | |
24602 | ||
24603 | Set the range of children to be returned by future invocations of | |
24604 | @code{-var-update}. | |
24605 | ||
24606 | @var{from} and @var{to} indicate the range of children to report. If | |
24607 | @var{from} or @var{to} is less than zero, the range is reset and all | |
24608 | children will be reported. Otherwise, children starting at @var{from} | |
24609 | (zero-based) and up to and excluding @var{to} will be reported. | |
24610 | ||
24611 | @subsubheading Example | |
24612 | ||
24613 | @smallexample | |
24614 | (gdb) | |
24615 | -var-set-update-range V 1 2 | |
24616 | ^done | |
24617 | @end smallexample | |
24618 | ||
b6313243 TT |
24619 | @subheading The @code{-var-set-visualizer} command |
24620 | @findex -var-set-visualizer | |
24621 | @anchor{-var-set-visualizer} | |
24622 | ||
24623 | @subsubheading Synopsis | |
24624 | ||
24625 | @smallexample | |
24626 | -var-set-visualizer @var{name} @var{visualizer} | |
24627 | @end smallexample | |
24628 | ||
24629 | Set a visualizer for the variable object @var{name}. | |
24630 | ||
24631 | @var{visualizer} is the visualizer to use. The special value | |
24632 | @samp{None} means to disable any visualizer in use. | |
24633 | ||
24634 | If not @samp{None}, @var{visualizer} must be a Python expression. | |
24635 | This expression must evaluate to a callable object which accepts a | |
24636 | single argument. @value{GDBN} will call this object with the value of | |
24637 | the varobj @var{name} as an argument (this is done so that the same | |
24638 | Python pretty-printing code can be used for both the CLI and MI). | |
24639 | When called, this object must return an object which conforms to the | |
24640 | pretty-printing interface (@pxref{Pretty Printing}). | |
24641 | ||
24642 | The pre-defined function @code{gdb.default_visualizer} may be used to | |
24643 | select a visualizer by following the built-in process | |
24644 | (@pxref{Selecting Pretty-Printers}). This is done automatically when | |
24645 | a varobj is created, and so ordinarily is not needed. | |
24646 | ||
24647 | This feature is only available if Python support is enabled. The MI | |
24648 | command @code{-list-features} (@pxref{GDB/MI Miscellaneous Commands}) | |
24649 | can be used to check this. | |
24650 | ||
24651 | @subsubheading Example | |
24652 | ||
24653 | Resetting the visualizer: | |
24654 | ||
24655 | @smallexample | |
24656 | (gdb) | |
24657 | -var-set-visualizer V None | |
24658 | ^done | |
24659 | @end smallexample | |
24660 | ||
24661 | Reselecting the default (type-based) visualizer: | |
24662 | ||
24663 | @smallexample | |
24664 | (gdb) | |
24665 | -var-set-visualizer V gdb.default_visualizer | |
24666 | ^done | |
24667 | @end smallexample | |
24668 | ||
24669 | Suppose @code{SomeClass} is a visualizer class. A lambda expression | |
24670 | can be used to instantiate this class for a varobj: | |
24671 | ||
24672 | @smallexample | |
24673 | (gdb) | |
24674 | -var-set-visualizer V "lambda val: SomeClass()" | |
24675 | ^done | |
24676 | @end smallexample | |
25d5ea92 | 24677 | |
a2c02241 NR |
24678 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
24679 | @node GDB/MI Data Manipulation | |
24680 | @section @sc{gdb/mi} Data Manipulation | |
922fbb7b | 24681 | |
a2c02241 NR |
24682 | @cindex data manipulation, in @sc{gdb/mi} |
24683 | @cindex @sc{gdb/mi}, data manipulation | |
24684 | This section describes the @sc{gdb/mi} commands that manipulate data: | |
24685 | examine memory and registers, evaluate expressions, etc. | |
24686 | ||
24687 | @c REMOVED FROM THE INTERFACE. | |
24688 | @c @subheading -data-assign | |
24689 | @c Change the value of a program variable. Plenty of side effects. | |
79a6e687 | 24690 | @c @subsubheading GDB Command |
a2c02241 NR |
24691 | @c set variable |
24692 | @c @subsubheading Example | |
24693 | @c N.A. | |
24694 | ||
24695 | @subheading The @code{-data-disassemble} Command | |
24696 | @findex -data-disassemble | |
922fbb7b AC |
24697 | |
24698 | @subsubheading Synopsis | |
24699 | ||
24700 | @smallexample | |
a2c02241 NR |
24701 | -data-disassemble |
24702 | [ -s @var{start-addr} -e @var{end-addr} ] | |
24703 | | [ -f @var{filename} -l @var{linenum} [ -n @var{lines} ] ] | |
24704 | -- @var{mode} | |
922fbb7b AC |
24705 | @end smallexample |
24706 | ||
a2c02241 NR |
24707 | @noindent |
24708 | Where: | |
24709 | ||
24710 | @table @samp | |
24711 | @item @var{start-addr} | |
24712 | is the beginning address (or @code{$pc}) | |
24713 | @item @var{end-addr} | |
24714 | is the end address | |
24715 | @item @var{filename} | |
24716 | is the name of the file to disassemble | |
24717 | @item @var{linenum} | |
24718 | is the line number to disassemble around | |
24719 | @item @var{lines} | |
d3e8051b | 24720 | is the number of disassembly lines to be produced. If it is -1, |
a2c02241 NR |
24721 | the whole function will be disassembled, in case no @var{end-addr} is |
24722 | specified. If @var{end-addr} is specified as a non-zero value, and | |
24723 | @var{lines} is lower than the number of disassembly lines between | |
24724 | @var{start-addr} and @var{end-addr}, only @var{lines} lines are | |
24725 | displayed; if @var{lines} is higher than the number of lines between | |
24726 | @var{start-addr} and @var{end-addr}, only the lines up to @var{end-addr} | |
24727 | are displayed. | |
24728 | @item @var{mode} | |
24729 | is either 0 (meaning only disassembly) or 1 (meaning mixed source and | |
24730 | disassembly). | |
24731 | @end table | |
24732 | ||
24733 | @subsubheading Result | |
24734 | ||
24735 | The output for each instruction is composed of four fields: | |
24736 | ||
24737 | @itemize @bullet | |
24738 | @item Address | |
24739 | @item Func-name | |
24740 | @item Offset | |
24741 | @item Instruction | |
24742 | @end itemize | |
24743 | ||
24744 | Note that whatever included in the instruction field, is not manipulated | |
d3e8051b | 24745 | directly by @sc{gdb/mi}, i.e., it is not possible to adjust its format. |
922fbb7b AC |
24746 | |
24747 | @subsubheading @value{GDBN} Command | |
24748 | ||
a2c02241 | 24749 | There's no direct mapping from this command to the CLI. |
922fbb7b AC |
24750 | |
24751 | @subsubheading Example | |
24752 | ||
a2c02241 NR |
24753 | Disassemble from the current value of @code{$pc} to @code{$pc + 20}: |
24754 | ||
922fbb7b | 24755 | @smallexample |
594fe323 | 24756 | (gdb) |
a2c02241 NR |
24757 | -data-disassemble -s $pc -e "$pc + 20" -- 0 |
24758 | ^done, | |
24759 | asm_insns=[ | |
24760 | @{address="0x000107c0",func-name="main",offset="4", | |
24761 | inst="mov 2, %o0"@}, | |
24762 | @{address="0x000107c4",func-name="main",offset="8", | |
24763 | inst="sethi %hi(0x11800), %o2"@}, | |
24764 | @{address="0x000107c8",func-name="main",offset="12", | |
24765 | inst="or %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"@}, | |
24766 | @{address="0x000107cc",func-name="main",offset="16", | |
24767 | inst="sethi %hi(0x11800), %o2"@}, | |
24768 | @{address="0x000107d0",func-name="main",offset="20", | |
24769 | inst="or %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"@}] | |
594fe323 | 24770 | (gdb) |
a2c02241 NR |
24771 | @end smallexample |
24772 | ||
24773 | Disassemble the whole @code{main} function. Line 32 is part of | |
24774 | @code{main}. | |
24775 | ||
24776 | @smallexample | |
24777 | -data-disassemble -f basics.c -l 32 -- 0 | |
24778 | ^done,asm_insns=[ | |
24779 | @{address="0x000107bc",func-name="main",offset="0", | |
24780 | inst="save %sp, -112, %sp"@}, | |
24781 | @{address="0x000107c0",func-name="main",offset="4", | |
24782 | inst="mov 2, %o0"@}, | |
24783 | @{address="0x000107c4",func-name="main",offset="8", | |
24784 | inst="sethi %hi(0x11800), %o2"@}, | |
24785 | [@dots{}] | |
24786 | @{address="0x0001081c",func-name="main",offset="96",inst="ret "@}, | |
24787 | @{address="0x00010820",func-name="main",offset="100",inst="restore "@}] | |
594fe323 | 24788 | (gdb) |
922fbb7b AC |
24789 | @end smallexample |
24790 | ||
a2c02241 | 24791 | Disassemble 3 instructions from the start of @code{main}: |
922fbb7b | 24792 | |
a2c02241 | 24793 | @smallexample |
594fe323 | 24794 | (gdb) |
a2c02241 NR |
24795 | -data-disassemble -f basics.c -l 32 -n 3 -- 0 |
24796 | ^done,asm_insns=[ | |
24797 | @{address="0x000107bc",func-name="main",offset="0", | |
24798 | inst="save %sp, -112, %sp"@}, | |
24799 | @{address="0x000107c0",func-name="main",offset="4", | |
24800 | inst="mov 2, %o0"@}, | |
24801 | @{address="0x000107c4",func-name="main",offset="8", | |
24802 | inst="sethi %hi(0x11800), %o2"@}] | |
594fe323 | 24803 | (gdb) |
a2c02241 NR |
24804 | @end smallexample |
24805 | ||
24806 | Disassemble 3 instructions from the start of @code{main} in mixed mode: | |
24807 | ||
24808 | @smallexample | |
594fe323 | 24809 | (gdb) |
a2c02241 NR |
24810 | -data-disassemble -f basics.c -l 32 -n 3 -- 1 |
24811 | ^done,asm_insns=[ | |
24812 | src_and_asm_line=@{line="31", | |
24813 | file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ | |
24814 | testsuite/gdb.mi/basics.c",line_asm_insn=[ | |
24815 | @{address="0x000107bc",func-name="main",offset="0", | |
24816 | inst="save %sp, -112, %sp"@}]@}, | |
24817 | src_and_asm_line=@{line="32", | |
24818 | file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ | |
24819 | testsuite/gdb.mi/basics.c",line_asm_insn=[ | |
24820 | @{address="0x000107c0",func-name="main",offset="4", | |
24821 | inst="mov 2, %o0"@}, | |
24822 | @{address="0x000107c4",func-name="main",offset="8", | |
24823 | inst="sethi %hi(0x11800), %o2"@}]@}] | |
594fe323 | 24824 | (gdb) |
a2c02241 NR |
24825 | @end smallexample |
24826 | ||
24827 | ||
24828 | @subheading The @code{-data-evaluate-expression} Command | |
24829 | @findex -data-evaluate-expression | |
922fbb7b AC |
24830 | |
24831 | @subsubheading Synopsis | |
24832 | ||
24833 | @smallexample | |
a2c02241 | 24834 | -data-evaluate-expression @var{expr} |
922fbb7b AC |
24835 | @end smallexample |
24836 | ||
a2c02241 NR |
24837 | Evaluate @var{expr} as an expression. The expression could contain an |
24838 | inferior function call. The function call will execute synchronously. | |
24839 | If the expression contains spaces, it must be enclosed in double quotes. | |
922fbb7b AC |
24840 | |
24841 | @subsubheading @value{GDBN} Command | |
24842 | ||
a2c02241 NR |
24843 | The corresponding @value{GDBN} commands are @samp{print}, @samp{output}, and |
24844 | @samp{call}. In @code{gdbtk} only, there's a corresponding | |
24845 | @samp{gdb_eval} command. | |
922fbb7b AC |
24846 | |
24847 | @subsubheading Example | |
24848 | ||
a2c02241 NR |
24849 | In the following example, the numbers that precede the commands are the |
24850 | @dfn{tokens} described in @ref{GDB/MI Command Syntax, ,@sc{gdb/mi} | |
24851 | Command Syntax}. Notice how @sc{gdb/mi} returns the same tokens in its | |
24852 | output. | |
24853 | ||
922fbb7b | 24854 | @smallexample |
a2c02241 NR |
24855 | 211-data-evaluate-expression A |
24856 | 211^done,value="1" | |
594fe323 | 24857 | (gdb) |
a2c02241 NR |
24858 | 311-data-evaluate-expression &A |
24859 | 311^done,value="0xefffeb7c" | |
594fe323 | 24860 | (gdb) |
a2c02241 NR |
24861 | 411-data-evaluate-expression A+3 |
24862 | 411^done,value="4" | |
594fe323 | 24863 | (gdb) |
a2c02241 NR |
24864 | 511-data-evaluate-expression "A + 3" |
24865 | 511^done,value="4" | |
594fe323 | 24866 | (gdb) |
a2c02241 | 24867 | @end smallexample |
922fbb7b AC |
24868 | |
24869 | ||
a2c02241 NR |
24870 | @subheading The @code{-data-list-changed-registers} Command |
24871 | @findex -data-list-changed-registers | |
922fbb7b AC |
24872 | |
24873 | @subsubheading Synopsis | |
24874 | ||
24875 | @smallexample | |
a2c02241 | 24876 | -data-list-changed-registers |
922fbb7b AC |
24877 | @end smallexample |
24878 | ||
a2c02241 | 24879 | Display a list of the registers that have changed. |
922fbb7b AC |
24880 | |
24881 | @subsubheading @value{GDBN} Command | |
24882 | ||
a2c02241 NR |
24883 | @value{GDBN} doesn't have a direct analog for this command; @code{gdbtk} |
24884 | has the corresponding command @samp{gdb_changed_register_list}. | |
922fbb7b AC |
24885 | |
24886 | @subsubheading Example | |
922fbb7b | 24887 | |
a2c02241 | 24888 | On a PPC MBX board: |
922fbb7b AC |
24889 | |
24890 | @smallexample | |
594fe323 | 24891 | (gdb) |
a2c02241 NR |
24892 | -exec-continue |
24893 | ^running | |
922fbb7b | 24894 | |
594fe323 | 24895 | (gdb) |
a47ec5fe AR |
24896 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",frame=@{ |
24897 | func="main",args=[],file="try.c",fullname="/home/foo/bar/try.c", | |
24898 | line="5"@} | |
594fe323 | 24899 | (gdb) |
a2c02241 NR |
24900 | -data-list-changed-registers |
24901 | ^done,changed-registers=["0","1","2","4","5","6","7","8","9", | |
24902 | "10","11","13","14","15","16","17","18","19","20","21","22","23", | |
24903 | "24","25","26","27","28","30","31","64","65","66","67","69"] | |
594fe323 | 24904 | (gdb) |
a2c02241 | 24905 | @end smallexample |
922fbb7b AC |
24906 | |
24907 | ||
a2c02241 NR |
24908 | @subheading The @code{-data-list-register-names} Command |
24909 | @findex -data-list-register-names | |
922fbb7b AC |
24910 | |
24911 | @subsubheading Synopsis | |
24912 | ||
24913 | @smallexample | |
a2c02241 | 24914 | -data-list-register-names [ ( @var{regno} )+ ] |
922fbb7b AC |
24915 | @end smallexample |
24916 | ||
a2c02241 NR |
24917 | Show a list of register names for the current target. If no arguments |
24918 | are given, it shows a list of the names of all the registers. If | |
24919 | integer numbers are given as arguments, it will print a list of the | |
24920 | names of the registers corresponding to the arguments. To ensure | |
24921 | consistency between a register name and its number, the output list may | |
24922 | include empty register names. | |
922fbb7b AC |
24923 | |
24924 | @subsubheading @value{GDBN} Command | |
24925 | ||
a2c02241 NR |
24926 | @value{GDBN} does not have a command which corresponds to |
24927 | @samp{-data-list-register-names}. In @code{gdbtk} there is a | |
24928 | corresponding command @samp{gdb_regnames}. | |
922fbb7b AC |
24929 | |
24930 | @subsubheading Example | |
922fbb7b | 24931 | |
a2c02241 NR |
24932 | For the PPC MBX board: |
24933 | @smallexample | |
594fe323 | 24934 | (gdb) |
a2c02241 NR |
24935 | -data-list-register-names |
24936 | ^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7", | |
24937 | "r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18", | |
24938 | "r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29", | |
24939 | "r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9", | |
24940 | "f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20", | |
24941 | "f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31", | |
24942 | "", "pc","ps","cr","lr","ctr","xer"] | |
594fe323 | 24943 | (gdb) |
a2c02241 NR |
24944 | -data-list-register-names 1 2 3 |
24945 | ^done,register-names=["r1","r2","r3"] | |
594fe323 | 24946 | (gdb) |
a2c02241 | 24947 | @end smallexample |
922fbb7b | 24948 | |
a2c02241 NR |
24949 | @subheading The @code{-data-list-register-values} Command |
24950 | @findex -data-list-register-values | |
922fbb7b AC |
24951 | |
24952 | @subsubheading Synopsis | |
24953 | ||
24954 | @smallexample | |
a2c02241 | 24955 | -data-list-register-values @var{fmt} [ ( @var{regno} )*] |
922fbb7b AC |
24956 | @end smallexample |
24957 | ||
a2c02241 NR |
24958 | Display the registers' contents. @var{fmt} is the format according to |
24959 | which the registers' contents are to be returned, followed by an optional | |
24960 | list of numbers specifying the registers to display. A missing list of | |
24961 | numbers indicates that the contents of all the registers must be returned. | |
24962 | ||
24963 | Allowed formats for @var{fmt} are: | |
24964 | ||
24965 | @table @code | |
24966 | @item x | |
24967 | Hexadecimal | |
24968 | @item o | |
24969 | Octal | |
24970 | @item t | |
24971 | Binary | |
24972 | @item d | |
24973 | Decimal | |
24974 | @item r | |
24975 | Raw | |
24976 | @item N | |
24977 | Natural | |
24978 | @end table | |
922fbb7b AC |
24979 | |
24980 | @subsubheading @value{GDBN} Command | |
24981 | ||
a2c02241 NR |
24982 | The corresponding @value{GDBN} commands are @samp{info reg}, @samp{info |
24983 | all-reg}, and (in @code{gdbtk}) @samp{gdb_fetch_registers}. | |
922fbb7b AC |
24984 | |
24985 | @subsubheading Example | |
922fbb7b | 24986 | |
a2c02241 NR |
24987 | For a PPC MBX board (note: line breaks are for readability only, they |
24988 | don't appear in the actual output): | |
24989 | ||
24990 | @smallexample | |
594fe323 | 24991 | (gdb) |
a2c02241 NR |
24992 | -data-list-register-values r 64 65 |
24993 | ^done,register-values=[@{number="64",value="0xfe00a300"@}, | |
24994 | @{number="65",value="0x00029002"@}] | |
594fe323 | 24995 | (gdb) |
a2c02241 NR |
24996 | -data-list-register-values x |
24997 | ^done,register-values=[@{number="0",value="0xfe0043c8"@}, | |
24998 | @{number="1",value="0x3fff88"@},@{number="2",value="0xfffffffe"@}, | |
24999 | @{number="3",value="0x0"@},@{number="4",value="0xa"@}, | |
25000 | @{number="5",value="0x3fff68"@},@{number="6",value="0x3fff58"@}, | |
25001 | @{number="7",value="0xfe011e98"@},@{number="8",value="0x2"@}, | |
25002 | @{number="9",value="0xfa202820"@},@{number="10",value="0xfa202808"@}, | |
25003 | @{number="11",value="0x1"@},@{number="12",value="0x0"@}, | |
25004 | @{number="13",value="0x4544"@},@{number="14",value="0xffdfffff"@}, | |
25005 | @{number="15",value="0xffffffff"@},@{number="16",value="0xfffffeff"@}, | |
25006 | @{number="17",value="0xefffffed"@},@{number="18",value="0xfffffffe"@}, | |
25007 | @{number="19",value="0xffffffff"@},@{number="20",value="0xffffffff"@}, | |
25008 | @{number="21",value="0xffffffff"@},@{number="22",value="0xfffffff7"@}, | |
25009 | @{number="23",value="0xffffffff"@},@{number="24",value="0xffffffff"@}, | |
25010 | @{number="25",value="0xffffffff"@},@{number="26",value="0xfffffffb"@}, | |
25011 | @{number="27",value="0xffffffff"@},@{number="28",value="0xf7bfffff"@}, | |
25012 | @{number="29",value="0x0"@},@{number="30",value="0xfe010000"@}, | |
25013 | @{number="31",value="0x0"@},@{number="32",value="0x0"@}, | |
25014 | @{number="33",value="0x0"@},@{number="34",value="0x0"@}, | |
25015 | @{number="35",value="0x0"@},@{number="36",value="0x0"@}, | |
25016 | @{number="37",value="0x0"@},@{number="38",value="0x0"@}, | |
25017 | @{number="39",value="0x0"@},@{number="40",value="0x0"@}, | |
25018 | @{number="41",value="0x0"@},@{number="42",value="0x0"@}, | |
25019 | @{number="43",value="0x0"@},@{number="44",value="0x0"@}, | |
25020 | @{number="45",value="0x0"@},@{number="46",value="0x0"@}, | |
25021 | @{number="47",value="0x0"@},@{number="48",value="0x0"@}, | |
25022 | @{number="49",value="0x0"@},@{number="50",value="0x0"@}, | |
25023 | @{number="51",value="0x0"@},@{number="52",value="0x0"@}, | |
25024 | @{number="53",value="0x0"@},@{number="54",value="0x0"@}, | |
25025 | @{number="55",value="0x0"@},@{number="56",value="0x0"@}, | |
25026 | @{number="57",value="0x0"@},@{number="58",value="0x0"@}, | |
25027 | @{number="59",value="0x0"@},@{number="60",value="0x0"@}, | |
25028 | @{number="61",value="0x0"@},@{number="62",value="0x0"@}, | |
25029 | @{number="63",value="0x0"@},@{number="64",value="0xfe00a300"@}, | |
25030 | @{number="65",value="0x29002"@},@{number="66",value="0x202f04b5"@}, | |
25031 | @{number="67",value="0xfe0043b0"@},@{number="68",value="0xfe00b3e4"@}, | |
25032 | @{number="69",value="0x20002b03"@}] | |
594fe323 | 25033 | (gdb) |
a2c02241 | 25034 | @end smallexample |
922fbb7b | 25035 | |
a2c02241 NR |
25036 | |
25037 | @subheading The @code{-data-read-memory} Command | |
25038 | @findex -data-read-memory | |
922fbb7b AC |
25039 | |
25040 | @subsubheading Synopsis | |
25041 | ||
25042 | @smallexample | |
a2c02241 NR |
25043 | -data-read-memory [ -o @var{byte-offset} ] |
25044 | @var{address} @var{word-format} @var{word-size} | |
25045 | @var{nr-rows} @var{nr-cols} [ @var{aschar} ] | |
922fbb7b AC |
25046 | @end smallexample |
25047 | ||
a2c02241 NR |
25048 | @noindent |
25049 | where: | |
922fbb7b | 25050 | |
a2c02241 NR |
25051 | @table @samp |
25052 | @item @var{address} | |
25053 | An expression specifying the address of the first memory word to be | |
25054 | read. Complex expressions containing embedded white space should be | |
25055 | quoted using the C convention. | |
922fbb7b | 25056 | |
a2c02241 NR |
25057 | @item @var{word-format} |
25058 | The format to be used to print the memory words. The notation is the | |
25059 | same as for @value{GDBN}'s @code{print} command (@pxref{Output Formats, | |
79a6e687 | 25060 | ,Output Formats}). |
922fbb7b | 25061 | |
a2c02241 NR |
25062 | @item @var{word-size} |
25063 | The size of each memory word in bytes. | |
922fbb7b | 25064 | |
a2c02241 NR |
25065 | @item @var{nr-rows} |
25066 | The number of rows in the output table. | |
922fbb7b | 25067 | |
a2c02241 NR |
25068 | @item @var{nr-cols} |
25069 | The number of columns in the output table. | |
922fbb7b | 25070 | |
a2c02241 NR |
25071 | @item @var{aschar} |
25072 | If present, indicates that each row should include an @sc{ascii} dump. The | |
25073 | value of @var{aschar} is used as a padding character when a byte is not a | |
25074 | member of the printable @sc{ascii} character set (printable @sc{ascii} | |
25075 | characters are those whose code is between 32 and 126, inclusively). | |
922fbb7b | 25076 | |
a2c02241 NR |
25077 | @item @var{byte-offset} |
25078 | An offset to add to the @var{address} before fetching memory. | |
25079 | @end table | |
922fbb7b | 25080 | |
a2c02241 NR |
25081 | This command displays memory contents as a table of @var{nr-rows} by |
25082 | @var{nr-cols} words, each word being @var{word-size} bytes. In total, | |
25083 | @code{@var{nr-rows} * @var{nr-cols} * @var{word-size}} bytes are read | |
25084 | (returned as @samp{total-bytes}). Should less than the requested number | |
25085 | of bytes be returned by the target, the missing words are identified | |
25086 | using @samp{N/A}. The number of bytes read from the target is returned | |
25087 | in @samp{nr-bytes} and the starting address used to read memory in | |
25088 | @samp{addr}. | |
25089 | ||
25090 | The address of the next/previous row or page is available in | |
25091 | @samp{next-row} and @samp{prev-row}, @samp{next-page} and | |
25092 | @samp{prev-page}. | |
922fbb7b AC |
25093 | |
25094 | @subsubheading @value{GDBN} Command | |
25095 | ||
a2c02241 NR |
25096 | The corresponding @value{GDBN} command is @samp{x}. @code{gdbtk} has |
25097 | @samp{gdb_get_mem} memory read command. | |
922fbb7b AC |
25098 | |
25099 | @subsubheading Example | |
32e7087d | 25100 | |
a2c02241 NR |
25101 | Read six bytes of memory starting at @code{bytes+6} but then offset by |
25102 | @code{-6} bytes. Format as three rows of two columns. One byte per | |
25103 | word. Display each word in hex. | |
32e7087d JB |
25104 | |
25105 | @smallexample | |
594fe323 | 25106 | (gdb) |
a2c02241 NR |
25107 | 9-data-read-memory -o -6 -- bytes+6 x 1 3 2 |
25108 | 9^done,addr="0x00001390",nr-bytes="6",total-bytes="6", | |
25109 | next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396", | |
25110 | prev-page="0x0000138a",memory=[ | |
25111 | @{addr="0x00001390",data=["0x00","0x01"]@}, | |
25112 | @{addr="0x00001392",data=["0x02","0x03"]@}, | |
25113 | @{addr="0x00001394",data=["0x04","0x05"]@}] | |
594fe323 | 25114 | (gdb) |
32e7087d JB |
25115 | @end smallexample |
25116 | ||
a2c02241 NR |
25117 | Read two bytes of memory starting at address @code{shorts + 64} and |
25118 | display as a single word formatted in decimal. | |
32e7087d | 25119 | |
32e7087d | 25120 | @smallexample |
594fe323 | 25121 | (gdb) |
a2c02241 NR |
25122 | 5-data-read-memory shorts+64 d 2 1 1 |
25123 | 5^done,addr="0x00001510",nr-bytes="2",total-bytes="2", | |
25124 | next-row="0x00001512",prev-row="0x0000150e", | |
25125 | next-page="0x00001512",prev-page="0x0000150e",memory=[ | |
25126 | @{addr="0x00001510",data=["128"]@}] | |
594fe323 | 25127 | (gdb) |
32e7087d JB |
25128 | @end smallexample |
25129 | ||
a2c02241 NR |
25130 | Read thirty two bytes of memory starting at @code{bytes+16} and format |
25131 | as eight rows of four columns. Include a string encoding with @samp{x} | |
25132 | used as the non-printable character. | |
922fbb7b AC |
25133 | |
25134 | @smallexample | |
594fe323 | 25135 | (gdb) |
a2c02241 NR |
25136 | 4-data-read-memory bytes+16 x 1 8 4 x |
25137 | 4^done,addr="0x000013a0",nr-bytes="32",total-bytes="32", | |
25138 | next-row="0x000013c0",prev-row="0x0000139c", | |
25139 | next-page="0x000013c0",prev-page="0x00001380",memory=[ | |
25140 | @{addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"@}, | |
25141 | @{addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"@}, | |
25142 | @{addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"@}, | |
25143 | @{addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"@}, | |
25144 | @{addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"@}, | |
25145 | @{addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"@}, | |
25146 | @{addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"@}, | |
25147 | @{addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"@}] | |
594fe323 | 25148 | (gdb) |
922fbb7b AC |
25149 | @end smallexample |
25150 | ||
a2c02241 NR |
25151 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25152 | @node GDB/MI Tracepoint Commands | |
25153 | @section @sc{gdb/mi} Tracepoint Commands | |
922fbb7b | 25154 | |
a2c02241 | 25155 | The tracepoint commands are not yet implemented. |
922fbb7b | 25156 | |
a2c02241 | 25157 | @c @subheading -trace-actions |
922fbb7b | 25158 | |
a2c02241 | 25159 | @c @subheading -trace-delete |
922fbb7b | 25160 | |
a2c02241 | 25161 | @c @subheading -trace-disable |
922fbb7b | 25162 | |
a2c02241 | 25163 | @c @subheading -trace-dump |
922fbb7b | 25164 | |
a2c02241 | 25165 | @c @subheading -trace-enable |
922fbb7b | 25166 | |
a2c02241 | 25167 | @c @subheading -trace-exists |
922fbb7b | 25168 | |
a2c02241 | 25169 | @c @subheading -trace-find |
922fbb7b | 25170 | |
a2c02241 | 25171 | @c @subheading -trace-frame-number |
922fbb7b | 25172 | |
a2c02241 | 25173 | @c @subheading -trace-info |
922fbb7b | 25174 | |
a2c02241 | 25175 | @c @subheading -trace-insert |
922fbb7b | 25176 | |
a2c02241 | 25177 | @c @subheading -trace-list |
922fbb7b | 25178 | |
a2c02241 | 25179 | @c @subheading -trace-pass-count |
922fbb7b | 25180 | |
a2c02241 | 25181 | @c @subheading -trace-save |
922fbb7b | 25182 | |
a2c02241 | 25183 | @c @subheading -trace-start |
922fbb7b | 25184 | |
a2c02241 | 25185 | @c @subheading -trace-stop |
922fbb7b | 25186 | |
922fbb7b | 25187 | |
a2c02241 NR |
25188 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25189 | @node GDB/MI Symbol Query | |
25190 | @section @sc{gdb/mi} Symbol Query Commands | |
922fbb7b AC |
25191 | |
25192 | ||
9901a55b | 25193 | @ignore |
a2c02241 NR |
25194 | @subheading The @code{-symbol-info-address} Command |
25195 | @findex -symbol-info-address | |
922fbb7b AC |
25196 | |
25197 | @subsubheading Synopsis | |
25198 | ||
25199 | @smallexample | |
a2c02241 | 25200 | -symbol-info-address @var{symbol} |
922fbb7b AC |
25201 | @end smallexample |
25202 | ||
a2c02241 | 25203 | Describe where @var{symbol} is stored. |
922fbb7b AC |
25204 | |
25205 | @subsubheading @value{GDBN} Command | |
25206 | ||
a2c02241 | 25207 | The corresponding @value{GDBN} command is @samp{info address}. |
922fbb7b AC |
25208 | |
25209 | @subsubheading Example | |
25210 | N.A. | |
25211 | ||
25212 | ||
a2c02241 NR |
25213 | @subheading The @code{-symbol-info-file} Command |
25214 | @findex -symbol-info-file | |
922fbb7b AC |
25215 | |
25216 | @subsubheading Synopsis | |
25217 | ||
25218 | @smallexample | |
a2c02241 | 25219 | -symbol-info-file |
922fbb7b AC |
25220 | @end smallexample |
25221 | ||
a2c02241 | 25222 | Show the file for the symbol. |
922fbb7b | 25223 | |
a2c02241 | 25224 | @subsubheading @value{GDBN} Command |
922fbb7b | 25225 | |
a2c02241 NR |
25226 | There's no equivalent @value{GDBN} command. @code{gdbtk} has |
25227 | @samp{gdb_find_file}. | |
922fbb7b AC |
25228 | |
25229 | @subsubheading Example | |
25230 | N.A. | |
25231 | ||
25232 | ||
a2c02241 NR |
25233 | @subheading The @code{-symbol-info-function} Command |
25234 | @findex -symbol-info-function | |
922fbb7b AC |
25235 | |
25236 | @subsubheading Synopsis | |
25237 | ||
25238 | @smallexample | |
a2c02241 | 25239 | -symbol-info-function |
922fbb7b AC |
25240 | @end smallexample |
25241 | ||
a2c02241 | 25242 | Show which function the symbol lives in. |
922fbb7b AC |
25243 | |
25244 | @subsubheading @value{GDBN} Command | |
25245 | ||
a2c02241 | 25246 | @samp{gdb_get_function} in @code{gdbtk}. |
922fbb7b AC |
25247 | |
25248 | @subsubheading Example | |
25249 | N.A. | |
25250 | ||
25251 | ||
a2c02241 NR |
25252 | @subheading The @code{-symbol-info-line} Command |
25253 | @findex -symbol-info-line | |
922fbb7b AC |
25254 | |
25255 | @subsubheading Synopsis | |
25256 | ||
25257 | @smallexample | |
a2c02241 | 25258 | -symbol-info-line |
922fbb7b AC |
25259 | @end smallexample |
25260 | ||
a2c02241 | 25261 | Show the core addresses of the code for a source line. |
922fbb7b | 25262 | |
a2c02241 | 25263 | @subsubheading @value{GDBN} Command |
922fbb7b | 25264 | |
a2c02241 NR |
25265 | The corresponding @value{GDBN} command is @samp{info line}. |
25266 | @code{gdbtk} has the @samp{gdb_get_line} and @samp{gdb_get_file} commands. | |
922fbb7b AC |
25267 | |
25268 | @subsubheading Example | |
a2c02241 | 25269 | N.A. |
922fbb7b AC |
25270 | |
25271 | ||
a2c02241 NR |
25272 | @subheading The @code{-symbol-info-symbol} Command |
25273 | @findex -symbol-info-symbol | |
07f31aa6 DJ |
25274 | |
25275 | @subsubheading Synopsis | |
25276 | ||
a2c02241 NR |
25277 | @smallexample |
25278 | -symbol-info-symbol @var{addr} | |
25279 | @end smallexample | |
07f31aa6 | 25280 | |
a2c02241 | 25281 | Describe what symbol is at location @var{addr}. |
07f31aa6 | 25282 | |
a2c02241 | 25283 | @subsubheading @value{GDBN} Command |
07f31aa6 | 25284 | |
a2c02241 | 25285 | The corresponding @value{GDBN} command is @samp{info symbol}. |
07f31aa6 DJ |
25286 | |
25287 | @subsubheading Example | |
a2c02241 | 25288 | N.A. |
07f31aa6 DJ |
25289 | |
25290 | ||
a2c02241 NR |
25291 | @subheading The @code{-symbol-list-functions} Command |
25292 | @findex -symbol-list-functions | |
922fbb7b AC |
25293 | |
25294 | @subsubheading Synopsis | |
25295 | ||
25296 | @smallexample | |
a2c02241 | 25297 | -symbol-list-functions |
922fbb7b AC |
25298 | @end smallexample |
25299 | ||
a2c02241 | 25300 | List the functions in the executable. |
922fbb7b AC |
25301 | |
25302 | @subsubheading @value{GDBN} Command | |
25303 | ||
a2c02241 NR |
25304 | @samp{info functions} in @value{GDBN}, @samp{gdb_listfunc} and |
25305 | @samp{gdb_search} in @code{gdbtk}. | |
922fbb7b AC |
25306 | |
25307 | @subsubheading Example | |
a2c02241 | 25308 | N.A. |
9901a55b | 25309 | @end ignore |
922fbb7b AC |
25310 | |
25311 | ||
a2c02241 NR |
25312 | @subheading The @code{-symbol-list-lines} Command |
25313 | @findex -symbol-list-lines | |
922fbb7b AC |
25314 | |
25315 | @subsubheading Synopsis | |
25316 | ||
25317 | @smallexample | |
a2c02241 | 25318 | -symbol-list-lines @var{filename} |
922fbb7b AC |
25319 | @end smallexample |
25320 | ||
a2c02241 NR |
25321 | Print the list of lines that contain code and their associated program |
25322 | addresses for the given source filename. The entries are sorted in | |
25323 | ascending PC order. | |
922fbb7b AC |
25324 | |
25325 | @subsubheading @value{GDBN} Command | |
25326 | ||
a2c02241 | 25327 | There is no corresponding @value{GDBN} command. |
922fbb7b AC |
25328 | |
25329 | @subsubheading Example | |
a2c02241 | 25330 | @smallexample |
594fe323 | 25331 | (gdb) |
a2c02241 NR |
25332 | -symbol-list-lines basics.c |
25333 | ^done,lines=[@{pc="0x08048554",line="7"@},@{pc="0x0804855a",line="8"@}] | |
594fe323 | 25334 | (gdb) |
a2c02241 | 25335 | @end smallexample |
922fbb7b AC |
25336 | |
25337 | ||
9901a55b | 25338 | @ignore |
a2c02241 NR |
25339 | @subheading The @code{-symbol-list-types} Command |
25340 | @findex -symbol-list-types | |
922fbb7b AC |
25341 | |
25342 | @subsubheading Synopsis | |
25343 | ||
25344 | @smallexample | |
a2c02241 | 25345 | -symbol-list-types |
922fbb7b AC |
25346 | @end smallexample |
25347 | ||
a2c02241 | 25348 | List all the type names. |
922fbb7b AC |
25349 | |
25350 | @subsubheading @value{GDBN} Command | |
25351 | ||
a2c02241 NR |
25352 | The corresponding commands are @samp{info types} in @value{GDBN}, |
25353 | @samp{gdb_search} in @code{gdbtk}. | |
922fbb7b AC |
25354 | |
25355 | @subsubheading Example | |
25356 | N.A. | |
25357 | ||
25358 | ||
a2c02241 NR |
25359 | @subheading The @code{-symbol-list-variables} Command |
25360 | @findex -symbol-list-variables | |
922fbb7b AC |
25361 | |
25362 | @subsubheading Synopsis | |
25363 | ||
25364 | @smallexample | |
a2c02241 | 25365 | -symbol-list-variables |
922fbb7b AC |
25366 | @end smallexample |
25367 | ||
a2c02241 | 25368 | List all the global and static variable names. |
922fbb7b AC |
25369 | |
25370 | @subsubheading @value{GDBN} Command | |
25371 | ||
a2c02241 | 25372 | @samp{info variables} in @value{GDBN}, @samp{gdb_search} in @code{gdbtk}. |
922fbb7b AC |
25373 | |
25374 | @subsubheading Example | |
25375 | N.A. | |
25376 | ||
25377 | ||
a2c02241 NR |
25378 | @subheading The @code{-symbol-locate} Command |
25379 | @findex -symbol-locate | |
922fbb7b AC |
25380 | |
25381 | @subsubheading Synopsis | |
25382 | ||
25383 | @smallexample | |
a2c02241 | 25384 | -symbol-locate |
922fbb7b AC |
25385 | @end smallexample |
25386 | ||
922fbb7b AC |
25387 | @subsubheading @value{GDBN} Command |
25388 | ||
a2c02241 | 25389 | @samp{gdb_loc} in @code{gdbtk}. |
922fbb7b AC |
25390 | |
25391 | @subsubheading Example | |
25392 | N.A. | |
25393 | ||
25394 | ||
a2c02241 NR |
25395 | @subheading The @code{-symbol-type} Command |
25396 | @findex -symbol-type | |
922fbb7b AC |
25397 | |
25398 | @subsubheading Synopsis | |
25399 | ||
25400 | @smallexample | |
a2c02241 | 25401 | -symbol-type @var{variable} |
922fbb7b AC |
25402 | @end smallexample |
25403 | ||
a2c02241 | 25404 | Show type of @var{variable}. |
922fbb7b | 25405 | |
a2c02241 | 25406 | @subsubheading @value{GDBN} Command |
922fbb7b | 25407 | |
a2c02241 NR |
25408 | The corresponding @value{GDBN} command is @samp{ptype}, @code{gdbtk} has |
25409 | @samp{gdb_obj_variable}. | |
25410 | ||
25411 | @subsubheading Example | |
25412 | N.A. | |
9901a55b | 25413 | @end ignore |
a2c02241 NR |
25414 | |
25415 | ||
25416 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
25417 | @node GDB/MI File Commands | |
25418 | @section @sc{gdb/mi} File Commands | |
25419 | ||
25420 | This section describes the GDB/MI commands to specify executable file names | |
25421 | and to read in and obtain symbol table information. | |
25422 | ||
25423 | @subheading The @code{-file-exec-and-symbols} Command | |
25424 | @findex -file-exec-and-symbols | |
25425 | ||
25426 | @subsubheading Synopsis | |
922fbb7b AC |
25427 | |
25428 | @smallexample | |
a2c02241 | 25429 | -file-exec-and-symbols @var{file} |
922fbb7b AC |
25430 | @end smallexample |
25431 | ||
a2c02241 NR |
25432 | Specify the executable file to be debugged. This file is the one from |
25433 | which the symbol table is also read. If no file is specified, the | |
25434 | command clears the executable and symbol information. If breakpoints | |
25435 | are set when using this command with no arguments, @value{GDBN} will produce | |
25436 | error messages. Otherwise, no output is produced, except a completion | |
25437 | notification. | |
25438 | ||
922fbb7b AC |
25439 | @subsubheading @value{GDBN} Command |
25440 | ||
a2c02241 | 25441 | The corresponding @value{GDBN} command is @samp{file}. |
922fbb7b AC |
25442 | |
25443 | @subsubheading Example | |
25444 | ||
25445 | @smallexample | |
594fe323 | 25446 | (gdb) |
a2c02241 NR |
25447 | -file-exec-and-symbols /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25448 | ^done | |
594fe323 | 25449 | (gdb) |
922fbb7b AC |
25450 | @end smallexample |
25451 | ||
922fbb7b | 25452 | |
a2c02241 NR |
25453 | @subheading The @code{-file-exec-file} Command |
25454 | @findex -file-exec-file | |
922fbb7b AC |
25455 | |
25456 | @subsubheading Synopsis | |
25457 | ||
25458 | @smallexample | |
a2c02241 | 25459 | -file-exec-file @var{file} |
922fbb7b AC |
25460 | @end smallexample |
25461 | ||
a2c02241 NR |
25462 | Specify the executable file to be debugged. Unlike |
25463 | @samp{-file-exec-and-symbols}, the symbol table is @emph{not} read | |
25464 | from this file. If used without argument, @value{GDBN} clears the information | |
25465 | about the executable file. No output is produced, except a completion | |
25466 | notification. | |
922fbb7b | 25467 | |
a2c02241 NR |
25468 | @subsubheading @value{GDBN} Command |
25469 | ||
25470 | The corresponding @value{GDBN} command is @samp{exec-file}. | |
922fbb7b AC |
25471 | |
25472 | @subsubheading Example | |
a2c02241 NR |
25473 | |
25474 | @smallexample | |
594fe323 | 25475 | (gdb) |
a2c02241 NR |
25476 | -file-exec-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25477 | ^done | |
594fe323 | 25478 | (gdb) |
a2c02241 | 25479 | @end smallexample |
922fbb7b AC |
25480 | |
25481 | ||
9901a55b | 25482 | @ignore |
a2c02241 NR |
25483 | @subheading The @code{-file-list-exec-sections} Command |
25484 | @findex -file-list-exec-sections | |
922fbb7b AC |
25485 | |
25486 | @subsubheading Synopsis | |
25487 | ||
25488 | @smallexample | |
a2c02241 | 25489 | -file-list-exec-sections |
922fbb7b AC |
25490 | @end smallexample |
25491 | ||
a2c02241 NR |
25492 | List the sections of the current executable file. |
25493 | ||
922fbb7b AC |
25494 | @subsubheading @value{GDBN} Command |
25495 | ||
a2c02241 NR |
25496 | The @value{GDBN} command @samp{info file} shows, among the rest, the same |
25497 | information as this command. @code{gdbtk} has a corresponding command | |
25498 | @samp{gdb_load_info}. | |
922fbb7b AC |
25499 | |
25500 | @subsubheading Example | |
25501 | N.A. | |
9901a55b | 25502 | @end ignore |
922fbb7b AC |
25503 | |
25504 | ||
a2c02241 NR |
25505 | @subheading The @code{-file-list-exec-source-file} Command |
25506 | @findex -file-list-exec-source-file | |
922fbb7b AC |
25507 | |
25508 | @subsubheading Synopsis | |
25509 | ||
25510 | @smallexample | |
a2c02241 | 25511 | -file-list-exec-source-file |
922fbb7b AC |
25512 | @end smallexample |
25513 | ||
a2c02241 | 25514 | List the line number, the current source file, and the absolute path |
44288b44 NR |
25515 | to the current source file for the current executable. The macro |
25516 | information field has a value of @samp{1} or @samp{0} depending on | |
25517 | whether or not the file includes preprocessor macro information. | |
922fbb7b AC |
25518 | |
25519 | @subsubheading @value{GDBN} Command | |
25520 | ||
a2c02241 | 25521 | The @value{GDBN} equivalent is @samp{info source} |
922fbb7b AC |
25522 | |
25523 | @subsubheading Example | |
25524 | ||
922fbb7b | 25525 | @smallexample |
594fe323 | 25526 | (gdb) |
a2c02241 | 25527 | 123-file-list-exec-source-file |
44288b44 | 25528 | 123^done,line="1",file="foo.c",fullname="/home/bar/foo.c,macro-info="1" |
594fe323 | 25529 | (gdb) |
922fbb7b AC |
25530 | @end smallexample |
25531 | ||
25532 | ||
a2c02241 NR |
25533 | @subheading The @code{-file-list-exec-source-files} Command |
25534 | @findex -file-list-exec-source-files | |
922fbb7b AC |
25535 | |
25536 | @subsubheading Synopsis | |
25537 | ||
25538 | @smallexample | |
a2c02241 | 25539 | -file-list-exec-source-files |
922fbb7b AC |
25540 | @end smallexample |
25541 | ||
a2c02241 NR |
25542 | List the source files for the current executable. |
25543 | ||
3f94c067 BW |
25544 | It will always output the filename, but only when @value{GDBN} can find |
25545 | the absolute file name of a source file, will it output the fullname. | |
922fbb7b AC |
25546 | |
25547 | @subsubheading @value{GDBN} Command | |
25548 | ||
a2c02241 NR |
25549 | The @value{GDBN} equivalent is @samp{info sources}. |
25550 | @code{gdbtk} has an analogous command @samp{gdb_listfiles}. | |
922fbb7b AC |
25551 | |
25552 | @subsubheading Example | |
922fbb7b | 25553 | @smallexample |
594fe323 | 25554 | (gdb) |
a2c02241 NR |
25555 | -file-list-exec-source-files |
25556 | ^done,files=[ | |
25557 | @{file=foo.c,fullname=/home/foo.c@}, | |
25558 | @{file=/home/bar.c,fullname=/home/bar.c@}, | |
25559 | @{file=gdb_could_not_find_fullpath.c@}] | |
594fe323 | 25560 | (gdb) |
922fbb7b AC |
25561 | @end smallexample |
25562 | ||
9901a55b | 25563 | @ignore |
a2c02241 NR |
25564 | @subheading The @code{-file-list-shared-libraries} Command |
25565 | @findex -file-list-shared-libraries | |
922fbb7b | 25566 | |
a2c02241 | 25567 | @subsubheading Synopsis |
922fbb7b | 25568 | |
a2c02241 NR |
25569 | @smallexample |
25570 | -file-list-shared-libraries | |
25571 | @end smallexample | |
922fbb7b | 25572 | |
a2c02241 | 25573 | List the shared libraries in the program. |
922fbb7b | 25574 | |
a2c02241 | 25575 | @subsubheading @value{GDBN} Command |
922fbb7b | 25576 | |
a2c02241 | 25577 | The corresponding @value{GDBN} command is @samp{info shared}. |
922fbb7b | 25578 | |
a2c02241 NR |
25579 | @subsubheading Example |
25580 | N.A. | |
922fbb7b AC |
25581 | |
25582 | ||
a2c02241 NR |
25583 | @subheading The @code{-file-list-symbol-files} Command |
25584 | @findex -file-list-symbol-files | |
922fbb7b | 25585 | |
a2c02241 | 25586 | @subsubheading Synopsis |
922fbb7b | 25587 | |
a2c02241 NR |
25588 | @smallexample |
25589 | -file-list-symbol-files | |
25590 | @end smallexample | |
922fbb7b | 25591 | |
a2c02241 | 25592 | List symbol files. |
922fbb7b | 25593 | |
a2c02241 | 25594 | @subsubheading @value{GDBN} Command |
922fbb7b | 25595 | |
a2c02241 | 25596 | The corresponding @value{GDBN} command is @samp{info file} (part of it). |
922fbb7b | 25597 | |
a2c02241 NR |
25598 | @subsubheading Example |
25599 | N.A. | |
9901a55b | 25600 | @end ignore |
922fbb7b | 25601 | |
922fbb7b | 25602 | |
a2c02241 NR |
25603 | @subheading The @code{-file-symbol-file} Command |
25604 | @findex -file-symbol-file | |
922fbb7b | 25605 | |
a2c02241 | 25606 | @subsubheading Synopsis |
922fbb7b | 25607 | |
a2c02241 NR |
25608 | @smallexample |
25609 | -file-symbol-file @var{file} | |
25610 | @end smallexample | |
922fbb7b | 25611 | |
a2c02241 NR |
25612 | Read symbol table info from the specified @var{file} argument. When |
25613 | used without arguments, clears @value{GDBN}'s symbol table info. No output is | |
25614 | produced, except for a completion notification. | |
922fbb7b | 25615 | |
a2c02241 | 25616 | @subsubheading @value{GDBN} Command |
922fbb7b | 25617 | |
a2c02241 | 25618 | The corresponding @value{GDBN} command is @samp{symbol-file}. |
922fbb7b | 25619 | |
a2c02241 | 25620 | @subsubheading Example |
922fbb7b | 25621 | |
a2c02241 | 25622 | @smallexample |
594fe323 | 25623 | (gdb) |
a2c02241 NR |
25624 | -file-symbol-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25625 | ^done | |
594fe323 | 25626 | (gdb) |
a2c02241 | 25627 | @end smallexample |
922fbb7b | 25628 | |
a2c02241 | 25629 | @ignore |
a2c02241 NR |
25630 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25631 | @node GDB/MI Memory Overlay Commands | |
25632 | @section @sc{gdb/mi} Memory Overlay Commands | |
922fbb7b | 25633 | |
a2c02241 | 25634 | The memory overlay commands are not implemented. |
922fbb7b | 25635 | |
a2c02241 | 25636 | @c @subheading -overlay-auto |
922fbb7b | 25637 | |
a2c02241 | 25638 | @c @subheading -overlay-list-mapping-state |
922fbb7b | 25639 | |
a2c02241 | 25640 | @c @subheading -overlay-list-overlays |
922fbb7b | 25641 | |
a2c02241 | 25642 | @c @subheading -overlay-map |
922fbb7b | 25643 | |
a2c02241 | 25644 | @c @subheading -overlay-off |
922fbb7b | 25645 | |
a2c02241 | 25646 | @c @subheading -overlay-on |
922fbb7b | 25647 | |
a2c02241 | 25648 | @c @subheading -overlay-unmap |
922fbb7b | 25649 | |
a2c02241 NR |
25650 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25651 | @node GDB/MI Signal Handling Commands | |
25652 | @section @sc{gdb/mi} Signal Handling Commands | |
922fbb7b | 25653 | |
a2c02241 | 25654 | Signal handling commands are not implemented. |
922fbb7b | 25655 | |
a2c02241 | 25656 | @c @subheading -signal-handle |
922fbb7b | 25657 | |
a2c02241 | 25658 | @c @subheading -signal-list-handle-actions |
922fbb7b | 25659 | |
a2c02241 NR |
25660 | @c @subheading -signal-list-signal-types |
25661 | @end ignore | |
922fbb7b | 25662 | |
922fbb7b | 25663 | |
a2c02241 NR |
25664 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25665 | @node GDB/MI Target Manipulation | |
25666 | @section @sc{gdb/mi} Target Manipulation Commands | |
922fbb7b AC |
25667 | |
25668 | ||
a2c02241 NR |
25669 | @subheading The @code{-target-attach} Command |
25670 | @findex -target-attach | |
922fbb7b AC |
25671 | |
25672 | @subsubheading Synopsis | |
25673 | ||
25674 | @smallexample | |
c3b108f7 | 25675 | -target-attach @var{pid} | @var{gid} | @var{file} |
922fbb7b AC |
25676 | @end smallexample |
25677 | ||
c3b108f7 VP |
25678 | Attach to a process @var{pid} or a file @var{file} outside of |
25679 | @value{GDBN}, or a thread group @var{gid}. If attaching to a thread | |
25680 | group, the id previously returned by | |
25681 | @samp{-list-thread-groups --available} must be used. | |
922fbb7b | 25682 | |
79a6e687 | 25683 | @subsubheading @value{GDBN} Command |
922fbb7b | 25684 | |
a2c02241 | 25685 | The corresponding @value{GDBN} command is @samp{attach}. |
922fbb7b | 25686 | |
a2c02241 | 25687 | @subsubheading Example |
b56e7235 VP |
25688 | @smallexample |
25689 | (gdb) | |
25690 | -target-attach 34 | |
25691 | =thread-created,id="1" | |
5ae4183a | 25692 | *stopped,thread-id="1",frame=@{addr="0xb7f7e410",func="bar",args=[]@} |
b56e7235 VP |
25693 | ^done |
25694 | (gdb) | |
25695 | @end smallexample | |
a2c02241 | 25696 | |
9901a55b | 25697 | @ignore |
a2c02241 NR |
25698 | @subheading The @code{-target-compare-sections} Command |
25699 | @findex -target-compare-sections | |
922fbb7b AC |
25700 | |
25701 | @subsubheading Synopsis | |
25702 | ||
25703 | @smallexample | |
a2c02241 | 25704 | -target-compare-sections [ @var{section} ] |
922fbb7b AC |
25705 | @end smallexample |
25706 | ||
a2c02241 NR |
25707 | Compare data of section @var{section} on target to the exec file. |
25708 | Without the argument, all sections are compared. | |
922fbb7b | 25709 | |
a2c02241 | 25710 | @subsubheading @value{GDBN} Command |
922fbb7b | 25711 | |
a2c02241 | 25712 | The @value{GDBN} equivalent is @samp{compare-sections}. |
922fbb7b | 25713 | |
a2c02241 NR |
25714 | @subsubheading Example |
25715 | N.A. | |
9901a55b | 25716 | @end ignore |
a2c02241 NR |
25717 | |
25718 | ||
25719 | @subheading The @code{-target-detach} Command | |
25720 | @findex -target-detach | |
922fbb7b AC |
25721 | |
25722 | @subsubheading Synopsis | |
25723 | ||
25724 | @smallexample | |
c3b108f7 | 25725 | -target-detach [ @var{pid} | @var{gid} ] |
922fbb7b AC |
25726 | @end smallexample |
25727 | ||
a2c02241 | 25728 | Detach from the remote target which normally resumes its execution. |
c3b108f7 VP |
25729 | If either @var{pid} or @var{gid} is specified, detaches from either |
25730 | the specified process, or specified thread group. There's no output. | |
a2c02241 | 25731 | |
79a6e687 | 25732 | @subsubheading @value{GDBN} Command |
a2c02241 NR |
25733 | |
25734 | The corresponding @value{GDBN} command is @samp{detach}. | |
25735 | ||
25736 | @subsubheading Example | |
922fbb7b AC |
25737 | |
25738 | @smallexample | |
594fe323 | 25739 | (gdb) |
a2c02241 NR |
25740 | -target-detach |
25741 | ^done | |
594fe323 | 25742 | (gdb) |
922fbb7b AC |
25743 | @end smallexample |
25744 | ||
25745 | ||
a2c02241 NR |
25746 | @subheading The @code{-target-disconnect} Command |
25747 | @findex -target-disconnect | |
922fbb7b AC |
25748 | |
25749 | @subsubheading Synopsis | |
25750 | ||
123dc839 | 25751 | @smallexample |
a2c02241 | 25752 | -target-disconnect |
123dc839 | 25753 | @end smallexample |
922fbb7b | 25754 | |
a2c02241 NR |
25755 | Disconnect from the remote target. There's no output and the target is |
25756 | generally not resumed. | |
25757 | ||
79a6e687 | 25758 | @subsubheading @value{GDBN} Command |
a2c02241 NR |
25759 | |
25760 | The corresponding @value{GDBN} command is @samp{disconnect}. | |
bc8ced35 NR |
25761 | |
25762 | @subsubheading Example | |
922fbb7b AC |
25763 | |
25764 | @smallexample | |
594fe323 | 25765 | (gdb) |
a2c02241 NR |
25766 | -target-disconnect |
25767 | ^done | |
594fe323 | 25768 | (gdb) |
922fbb7b AC |
25769 | @end smallexample |
25770 | ||
25771 | ||
a2c02241 NR |
25772 | @subheading The @code{-target-download} Command |
25773 | @findex -target-download | |
922fbb7b AC |
25774 | |
25775 | @subsubheading Synopsis | |
25776 | ||
25777 | @smallexample | |
a2c02241 | 25778 | -target-download |
922fbb7b AC |
25779 | @end smallexample |
25780 | ||
a2c02241 NR |
25781 | Loads the executable onto the remote target. |
25782 | It prints out an update message every half second, which includes the fields: | |
25783 | ||
25784 | @table @samp | |
25785 | @item section | |
25786 | The name of the section. | |
25787 | @item section-sent | |
25788 | The size of what has been sent so far for that section. | |
25789 | @item section-size | |
25790 | The size of the section. | |
25791 | @item total-sent | |
25792 | The total size of what was sent so far (the current and the previous sections). | |
25793 | @item total-size | |
25794 | The size of the overall executable to download. | |
25795 | @end table | |
25796 | ||
25797 | @noindent | |
25798 | Each message is sent as status record (@pxref{GDB/MI Output Syntax, , | |
25799 | @sc{gdb/mi} Output Syntax}). | |
25800 | ||
25801 | In addition, it prints the name and size of the sections, as they are | |
25802 | downloaded. These messages include the following fields: | |
25803 | ||
25804 | @table @samp | |
25805 | @item section | |
25806 | The name of the section. | |
25807 | @item section-size | |
25808 | The size of the section. | |
25809 | @item total-size | |
25810 | The size of the overall executable to download. | |
25811 | @end table | |
25812 | ||
25813 | @noindent | |
25814 | At the end, a summary is printed. | |
25815 | ||
25816 | @subsubheading @value{GDBN} Command | |
25817 | ||
25818 | The corresponding @value{GDBN} command is @samp{load}. | |
25819 | ||
25820 | @subsubheading Example | |
25821 | ||
25822 | Note: each status message appears on a single line. Here the messages | |
25823 | have been broken down so that they can fit onto a page. | |
922fbb7b AC |
25824 | |
25825 | @smallexample | |
594fe323 | 25826 | (gdb) |
a2c02241 NR |
25827 | -target-download |
25828 | +download,@{section=".text",section-size="6668",total-size="9880"@} | |
25829 | +download,@{section=".text",section-sent="512",section-size="6668", | |
25830 | total-sent="512",total-size="9880"@} | |
25831 | +download,@{section=".text",section-sent="1024",section-size="6668", | |
25832 | total-sent="1024",total-size="9880"@} | |
25833 | +download,@{section=".text",section-sent="1536",section-size="6668", | |
25834 | total-sent="1536",total-size="9880"@} | |
25835 | +download,@{section=".text",section-sent="2048",section-size="6668", | |
25836 | total-sent="2048",total-size="9880"@} | |
25837 | +download,@{section=".text",section-sent="2560",section-size="6668", | |
25838 | total-sent="2560",total-size="9880"@} | |
25839 | +download,@{section=".text",section-sent="3072",section-size="6668", | |
25840 | total-sent="3072",total-size="9880"@} | |
25841 | +download,@{section=".text",section-sent="3584",section-size="6668", | |
25842 | total-sent="3584",total-size="9880"@} | |
25843 | +download,@{section=".text",section-sent="4096",section-size="6668", | |
25844 | total-sent="4096",total-size="9880"@} | |
25845 | +download,@{section=".text",section-sent="4608",section-size="6668", | |
25846 | total-sent="4608",total-size="9880"@} | |
25847 | +download,@{section=".text",section-sent="5120",section-size="6668", | |
25848 | total-sent="5120",total-size="9880"@} | |
25849 | +download,@{section=".text",section-sent="5632",section-size="6668", | |
25850 | total-sent="5632",total-size="9880"@} | |
25851 | +download,@{section=".text",section-sent="6144",section-size="6668", | |
25852 | total-sent="6144",total-size="9880"@} | |
25853 | +download,@{section=".text",section-sent="6656",section-size="6668", | |
25854 | total-sent="6656",total-size="9880"@} | |
25855 | +download,@{section=".init",section-size="28",total-size="9880"@} | |
25856 | +download,@{section=".fini",section-size="28",total-size="9880"@} | |
25857 | +download,@{section=".data",section-size="3156",total-size="9880"@} | |
25858 | +download,@{section=".data",section-sent="512",section-size="3156", | |
25859 | total-sent="7236",total-size="9880"@} | |
25860 | +download,@{section=".data",section-sent="1024",section-size="3156", | |
25861 | total-sent="7748",total-size="9880"@} | |
25862 | +download,@{section=".data",section-sent="1536",section-size="3156", | |
25863 | total-sent="8260",total-size="9880"@} | |
25864 | +download,@{section=".data",section-sent="2048",section-size="3156", | |
25865 | total-sent="8772",total-size="9880"@} | |
25866 | +download,@{section=".data",section-sent="2560",section-size="3156", | |
25867 | total-sent="9284",total-size="9880"@} | |
25868 | +download,@{section=".data",section-sent="3072",section-size="3156", | |
25869 | total-sent="9796",total-size="9880"@} | |
25870 | ^done,address="0x10004",load-size="9880",transfer-rate="6586", | |
25871 | write-rate="429" | |
594fe323 | 25872 | (gdb) |
922fbb7b AC |
25873 | @end smallexample |
25874 | ||
25875 | ||
9901a55b | 25876 | @ignore |
a2c02241 NR |
25877 | @subheading The @code{-target-exec-status} Command |
25878 | @findex -target-exec-status | |
922fbb7b AC |
25879 | |
25880 | @subsubheading Synopsis | |
25881 | ||
25882 | @smallexample | |
a2c02241 | 25883 | -target-exec-status |
922fbb7b AC |
25884 | @end smallexample |
25885 | ||
a2c02241 NR |
25886 | Provide information on the state of the target (whether it is running or |
25887 | not, for instance). | |
922fbb7b | 25888 | |
a2c02241 | 25889 | @subsubheading @value{GDBN} Command |
922fbb7b | 25890 | |
a2c02241 NR |
25891 | There's no equivalent @value{GDBN} command. |
25892 | ||
25893 | @subsubheading Example | |
25894 | N.A. | |
922fbb7b | 25895 | |
a2c02241 NR |
25896 | |
25897 | @subheading The @code{-target-list-available-targets} Command | |
25898 | @findex -target-list-available-targets | |
922fbb7b AC |
25899 | |
25900 | @subsubheading Synopsis | |
25901 | ||
25902 | @smallexample | |
a2c02241 | 25903 | -target-list-available-targets |
922fbb7b AC |
25904 | @end smallexample |
25905 | ||
a2c02241 | 25906 | List the possible targets to connect to. |
922fbb7b | 25907 | |
a2c02241 | 25908 | @subsubheading @value{GDBN} Command |
922fbb7b | 25909 | |
a2c02241 | 25910 | The corresponding @value{GDBN} command is @samp{help target}. |
922fbb7b | 25911 | |
a2c02241 NR |
25912 | @subsubheading Example |
25913 | N.A. | |
25914 | ||
25915 | ||
25916 | @subheading The @code{-target-list-current-targets} Command | |
25917 | @findex -target-list-current-targets | |
922fbb7b AC |
25918 | |
25919 | @subsubheading Synopsis | |
25920 | ||
25921 | @smallexample | |
a2c02241 | 25922 | -target-list-current-targets |
922fbb7b AC |
25923 | @end smallexample |
25924 | ||
a2c02241 | 25925 | Describe the current target. |
922fbb7b | 25926 | |
a2c02241 | 25927 | @subsubheading @value{GDBN} Command |
922fbb7b | 25928 | |
a2c02241 NR |
25929 | The corresponding information is printed by @samp{info file} (among |
25930 | other things). | |
922fbb7b | 25931 | |
a2c02241 NR |
25932 | @subsubheading Example |
25933 | N.A. | |
25934 | ||
25935 | ||
25936 | @subheading The @code{-target-list-parameters} Command | |
25937 | @findex -target-list-parameters | |
922fbb7b AC |
25938 | |
25939 | @subsubheading Synopsis | |
25940 | ||
25941 | @smallexample | |
a2c02241 | 25942 | -target-list-parameters |
922fbb7b AC |
25943 | @end smallexample |
25944 | ||
a2c02241 | 25945 | @c ???? |
9901a55b | 25946 | @end ignore |
a2c02241 NR |
25947 | |
25948 | @subsubheading @value{GDBN} Command | |
25949 | ||
25950 | No equivalent. | |
922fbb7b AC |
25951 | |
25952 | @subsubheading Example | |
a2c02241 NR |
25953 | N.A. |
25954 | ||
25955 | ||
25956 | @subheading The @code{-target-select} Command | |
25957 | @findex -target-select | |
25958 | ||
25959 | @subsubheading Synopsis | |
922fbb7b AC |
25960 | |
25961 | @smallexample | |
a2c02241 | 25962 | -target-select @var{type} @var{parameters @dots{}} |
922fbb7b AC |
25963 | @end smallexample |
25964 | ||
a2c02241 | 25965 | Connect @value{GDBN} to the remote target. This command takes two args: |
922fbb7b | 25966 | |
a2c02241 NR |
25967 | @table @samp |
25968 | @item @var{type} | |
75c99385 | 25969 | The type of target, for instance @samp{remote}, etc. |
a2c02241 NR |
25970 | @item @var{parameters} |
25971 | Device names, host names and the like. @xref{Target Commands, , | |
79a6e687 | 25972 | Commands for Managing Targets}, for more details. |
a2c02241 NR |
25973 | @end table |
25974 | ||
25975 | The output is a connection notification, followed by the address at | |
25976 | which the target program is, in the following form: | |
922fbb7b AC |
25977 | |
25978 | @smallexample | |
a2c02241 NR |
25979 | ^connected,addr="@var{address}",func="@var{function name}", |
25980 | args=[@var{arg list}] | |
922fbb7b AC |
25981 | @end smallexample |
25982 | ||
a2c02241 NR |
25983 | @subsubheading @value{GDBN} Command |
25984 | ||
25985 | The corresponding @value{GDBN} command is @samp{target}. | |
265eeb58 NR |
25986 | |
25987 | @subsubheading Example | |
922fbb7b | 25988 | |
265eeb58 | 25989 | @smallexample |
594fe323 | 25990 | (gdb) |
75c99385 | 25991 | -target-select remote /dev/ttya |
a2c02241 | 25992 | ^connected,addr="0xfe00a300",func="??",args=[] |
594fe323 | 25993 | (gdb) |
265eeb58 | 25994 | @end smallexample |
ef21caaf | 25995 | |
a6b151f1 DJ |
25996 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25997 | @node GDB/MI File Transfer Commands | |
25998 | @section @sc{gdb/mi} File Transfer Commands | |
25999 | ||
26000 | ||
26001 | @subheading The @code{-target-file-put} Command | |
26002 | @findex -target-file-put | |
26003 | ||
26004 | @subsubheading Synopsis | |
26005 | ||
26006 | @smallexample | |
26007 | -target-file-put @var{hostfile} @var{targetfile} | |
26008 | @end smallexample | |
26009 | ||
26010 | Copy file @var{hostfile} from the host system (the machine running | |
26011 | @value{GDBN}) to @var{targetfile} on the target system. | |
26012 | ||
26013 | @subsubheading @value{GDBN} Command | |
26014 | ||
26015 | The corresponding @value{GDBN} command is @samp{remote put}. | |
26016 | ||
26017 | @subsubheading Example | |
26018 | ||
26019 | @smallexample | |
26020 | (gdb) | |
26021 | -target-file-put localfile remotefile | |
26022 | ^done | |
26023 | (gdb) | |
26024 | @end smallexample | |
26025 | ||
26026 | ||
1763a388 | 26027 | @subheading The @code{-target-file-get} Command |
a6b151f1 DJ |
26028 | @findex -target-file-get |
26029 | ||
26030 | @subsubheading Synopsis | |
26031 | ||
26032 | @smallexample | |
26033 | -target-file-get @var{targetfile} @var{hostfile} | |
26034 | @end smallexample | |
26035 | ||
26036 | Copy file @var{targetfile} from the target system to @var{hostfile} | |
26037 | on the host system. | |
26038 | ||
26039 | @subsubheading @value{GDBN} Command | |
26040 | ||
26041 | The corresponding @value{GDBN} command is @samp{remote get}. | |
26042 | ||
26043 | @subsubheading Example | |
26044 | ||
26045 | @smallexample | |
26046 | (gdb) | |
26047 | -target-file-get remotefile localfile | |
26048 | ^done | |
26049 | (gdb) | |
26050 | @end smallexample | |
26051 | ||
26052 | ||
26053 | @subheading The @code{-target-file-delete} Command | |
26054 | @findex -target-file-delete | |
26055 | ||
26056 | @subsubheading Synopsis | |
26057 | ||
26058 | @smallexample | |
26059 | -target-file-delete @var{targetfile} | |
26060 | @end smallexample | |
26061 | ||
26062 | Delete @var{targetfile} from the target system. | |
26063 | ||
26064 | @subsubheading @value{GDBN} Command | |
26065 | ||
26066 | The corresponding @value{GDBN} command is @samp{remote delete}. | |
26067 | ||
26068 | @subsubheading Example | |
26069 | ||
26070 | @smallexample | |
26071 | (gdb) | |
26072 | -target-file-delete remotefile | |
26073 | ^done | |
26074 | (gdb) | |
26075 | @end smallexample | |
26076 | ||
26077 | ||
ef21caaf NR |
26078 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
26079 | @node GDB/MI Miscellaneous Commands | |
26080 | @section Miscellaneous @sc{gdb/mi} Commands | |
26081 | ||
26082 | @c @subheading -gdb-complete | |
26083 | ||
26084 | @subheading The @code{-gdb-exit} Command | |
26085 | @findex -gdb-exit | |
26086 | ||
26087 | @subsubheading Synopsis | |
26088 | ||
26089 | @smallexample | |
26090 | -gdb-exit | |
26091 | @end smallexample | |
26092 | ||
26093 | Exit @value{GDBN} immediately. | |
26094 | ||
26095 | @subsubheading @value{GDBN} Command | |
26096 | ||
26097 | Approximately corresponds to @samp{quit}. | |
26098 | ||
26099 | @subsubheading Example | |
26100 | ||
26101 | @smallexample | |
594fe323 | 26102 | (gdb) |
ef21caaf NR |
26103 | -gdb-exit |
26104 | ^exit | |
26105 | @end smallexample | |
26106 | ||
a2c02241 | 26107 | |
9901a55b | 26108 | @ignore |
a2c02241 NR |
26109 | @subheading The @code{-exec-abort} Command |
26110 | @findex -exec-abort | |
26111 | ||
26112 | @subsubheading Synopsis | |
26113 | ||
26114 | @smallexample | |
26115 | -exec-abort | |
26116 | @end smallexample | |
26117 | ||
26118 | Kill the inferior running program. | |
26119 | ||
26120 | @subsubheading @value{GDBN} Command | |
26121 | ||
26122 | The corresponding @value{GDBN} command is @samp{kill}. | |
26123 | ||
26124 | @subsubheading Example | |
26125 | N.A. | |
9901a55b | 26126 | @end ignore |
a2c02241 NR |
26127 | |
26128 | ||
ef21caaf NR |
26129 | @subheading The @code{-gdb-set} Command |
26130 | @findex -gdb-set | |
26131 | ||
26132 | @subsubheading Synopsis | |
26133 | ||
26134 | @smallexample | |
26135 | -gdb-set | |
26136 | @end smallexample | |
26137 | ||
26138 | Set an internal @value{GDBN} variable. | |
26139 | @c IS THIS A DOLLAR VARIABLE? OR SOMETHING LIKE ANNOTATE ????? | |
26140 | ||
26141 | @subsubheading @value{GDBN} Command | |
26142 | ||
26143 | The corresponding @value{GDBN} command is @samp{set}. | |
26144 | ||
26145 | @subsubheading Example | |
26146 | ||
26147 | @smallexample | |
594fe323 | 26148 | (gdb) |
ef21caaf NR |
26149 | -gdb-set $foo=3 |
26150 | ^done | |
594fe323 | 26151 | (gdb) |
ef21caaf NR |
26152 | @end smallexample |
26153 | ||
26154 | ||
26155 | @subheading The @code{-gdb-show} Command | |
26156 | @findex -gdb-show | |
26157 | ||
26158 | @subsubheading Synopsis | |
26159 | ||
26160 | @smallexample | |
26161 | -gdb-show | |
26162 | @end smallexample | |
26163 | ||
26164 | Show the current value of a @value{GDBN} variable. | |
26165 | ||
79a6e687 | 26166 | @subsubheading @value{GDBN} Command |
ef21caaf NR |
26167 | |
26168 | The corresponding @value{GDBN} command is @samp{show}. | |
26169 | ||
26170 | @subsubheading Example | |
26171 | ||
26172 | @smallexample | |
594fe323 | 26173 | (gdb) |
ef21caaf NR |
26174 | -gdb-show annotate |
26175 | ^done,value="0" | |
594fe323 | 26176 | (gdb) |
ef21caaf NR |
26177 | @end smallexample |
26178 | ||
26179 | @c @subheading -gdb-source | |
26180 | ||
26181 | ||
26182 | @subheading The @code{-gdb-version} Command | |
26183 | @findex -gdb-version | |
26184 | ||
26185 | @subsubheading Synopsis | |
26186 | ||
26187 | @smallexample | |
26188 | -gdb-version | |
26189 | @end smallexample | |
26190 | ||
26191 | Show version information for @value{GDBN}. Used mostly in testing. | |
26192 | ||
26193 | @subsubheading @value{GDBN} Command | |
26194 | ||
26195 | The @value{GDBN} equivalent is @samp{show version}. @value{GDBN} by | |
26196 | default shows this information when you start an interactive session. | |
26197 | ||
26198 | @subsubheading Example | |
26199 | ||
26200 | @c This example modifies the actual output from GDB to avoid overfull | |
26201 | @c box in TeX. | |
26202 | @smallexample | |
594fe323 | 26203 | (gdb) |
ef21caaf NR |
26204 | -gdb-version |
26205 | ~GNU gdb 5.2.1 | |
26206 | ~Copyright 2000 Free Software Foundation, Inc. | |
26207 | ~GDB is free software, covered by the GNU General Public License, and | |
26208 | ~you are welcome to change it and/or distribute copies of it under | |
26209 | ~ certain conditions. | |
26210 | ~Type "show copying" to see the conditions. | |
26211 | ~There is absolutely no warranty for GDB. Type "show warranty" for | |
26212 | ~ details. | |
26213 | ~This GDB was configured as | |
26214 | "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi". | |
26215 | ^done | |
594fe323 | 26216 | (gdb) |
ef21caaf NR |
26217 | @end smallexample |
26218 | ||
084344da VP |
26219 | @subheading The @code{-list-features} Command |
26220 | @findex -list-features | |
26221 | ||
26222 | Returns a list of particular features of the MI protocol that | |
26223 | this version of gdb implements. A feature can be a command, | |
26224 | or a new field in an output of some command, or even an | |
26225 | important bugfix. While a frontend can sometimes detect presence | |
26226 | of a feature at runtime, it is easier to perform detection at debugger | |
26227 | startup. | |
26228 | ||
26229 | The command returns a list of strings, with each string naming an | |
26230 | available feature. Each returned string is just a name, it does not | |
26231 | have any internal structure. The list of possible feature names | |
26232 | is given below. | |
26233 | ||
26234 | Example output: | |
26235 | ||
26236 | @smallexample | |
26237 | (gdb) -list-features | |
26238 | ^done,result=["feature1","feature2"] | |
26239 | @end smallexample | |
26240 | ||
26241 | The current list of features is: | |
26242 | ||
30e026bb VP |
26243 | @table @samp |
26244 | @item frozen-varobjs | |
26245 | Indicates presence of the @code{-var-set-frozen} command, as well | |
26246 | as possible presense of the @code{frozen} field in the output | |
26247 | of @code{-varobj-create}. | |
26248 | @item pending-breakpoints | |
26249 | Indicates presence of the @option{-f} option to the @code{-break-insert} command. | |
b6313243 TT |
26250 | @item python |
26251 | Indicates presence of Python scripting support, Python-based | |
26252 | pretty-printing commands, and possible presence of the | |
26253 | @samp{display_hint} field in the output of @code{-var-list-children} | |
30e026bb VP |
26254 | @item thread-info |
26255 | Indicates presence of the @code{-thread-info} command. | |
8b4ed427 | 26256 | |
30e026bb | 26257 | @end table |
084344da | 26258 | |
c6ebd6cf VP |
26259 | @subheading The @code{-list-target-features} Command |
26260 | @findex -list-target-features | |
26261 | ||
26262 | Returns a list of particular features that are supported by the | |
26263 | target. Those features affect the permitted MI commands, but | |
26264 | unlike the features reported by the @code{-list-features} command, the | |
26265 | features depend on which target GDB is using at the moment. Whenever | |
26266 | a target can change, due to commands such as @code{-target-select}, | |
26267 | @code{-target-attach} or @code{-exec-run}, the list of target features | |
26268 | may change, and the frontend should obtain it again. | |
26269 | Example output: | |
26270 | ||
26271 | @smallexample | |
26272 | (gdb) -list-features | |
26273 | ^done,result=["async"] | |
26274 | @end smallexample | |
26275 | ||
26276 | The current list of features is: | |
26277 | ||
26278 | @table @samp | |
26279 | @item async | |
26280 | Indicates that the target is capable of asynchronous command | |
26281 | execution, which means that @value{GDBN} will accept further commands | |
26282 | while the target is running. | |
26283 | ||
26284 | @end table | |
26285 | ||
c3b108f7 VP |
26286 | @subheading The @code{-list-thread-groups} Command |
26287 | @findex -list-thread-groups | |
26288 | ||
26289 | @subheading Synopsis | |
26290 | ||
26291 | @smallexample | |
26292 | -list-thread-groups [ --available ] [ @var{group} ] | |
26293 | @end smallexample | |
26294 | ||
26295 | When used without the @var{group} parameter, lists top-level thread | |
26296 | groups that are being debugged. When used with the @var{group} | |
26297 | parameter, the children of the specified group are listed. The | |
26298 | children can be either threads, or other groups. At present, | |
26299 | @value{GDBN} will not report both threads and groups as children at | |
26300 | the same time, but it may change in future. | |
26301 | ||
26302 | With the @samp{--available} option, instead of reporting groups that | |
26303 | are been debugged, GDB will report all thread groups available on the | |
26304 | target. Using the @samp{--available} option together with @var{group} | |
26305 | is not allowed. | |
26306 | ||
26307 | @subheading Example | |
26308 | ||
26309 | @smallexample | |
26310 | @value{GDBP} | |
26311 | -list-thread-groups | |
26312 | ^done,groups=[@{id="17",type="process",pid="yyy",num_children="2"@}] | |
26313 | -list-thread-groups 17 | |
26314 | ^done,threads=[@{id="2",target-id="Thread 0xb7e14b90 (LWP 21257)", | |
26315 | frame=@{level="0",addr="0xffffe410",func="__kernel_vsyscall",args=[]@},state="running"@}, | |
26316 | @{id="1",target-id="Thread 0xb7e156b0 (LWP 21254)", | |
26317 | frame=@{level="0",addr="0x0804891f",func="foo",args=[@{name="i",value="10"@}], | |
26318 | file="/tmp/a.c",fullname="/tmp/a.c",line="158"@},state="running"@}]] | |
26319 | @end smallexample | |
c6ebd6cf | 26320 | |
ef21caaf NR |
26321 | @subheading The @code{-interpreter-exec} Command |
26322 | @findex -interpreter-exec | |
26323 | ||
26324 | @subheading Synopsis | |
26325 | ||
26326 | @smallexample | |
26327 | -interpreter-exec @var{interpreter} @var{command} | |
26328 | @end smallexample | |
a2c02241 | 26329 | @anchor{-interpreter-exec} |
ef21caaf NR |
26330 | |
26331 | Execute the specified @var{command} in the given @var{interpreter}. | |
26332 | ||
26333 | @subheading @value{GDBN} Command | |
26334 | ||
26335 | The corresponding @value{GDBN} command is @samp{interpreter-exec}. | |
26336 | ||
26337 | @subheading Example | |
26338 | ||
26339 | @smallexample | |
594fe323 | 26340 | (gdb) |
ef21caaf NR |
26341 | -interpreter-exec console "break main" |
26342 | &"During symbol reading, couldn't parse type; debugger out of date?.\n" | |
26343 | &"During symbol reading, bad structure-type format.\n" | |
26344 | ~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n" | |
26345 | ^done | |
594fe323 | 26346 | (gdb) |
ef21caaf NR |
26347 | @end smallexample |
26348 | ||
26349 | @subheading The @code{-inferior-tty-set} Command | |
26350 | @findex -inferior-tty-set | |
26351 | ||
26352 | @subheading Synopsis | |
26353 | ||
26354 | @smallexample | |
26355 | -inferior-tty-set /dev/pts/1 | |
26356 | @end smallexample | |
26357 | ||
26358 | Set terminal for future runs of the program being debugged. | |
26359 | ||
26360 | @subheading @value{GDBN} Command | |
26361 | ||
26362 | The corresponding @value{GDBN} command is @samp{set inferior-tty} /dev/pts/1. | |
26363 | ||
26364 | @subheading Example | |
26365 | ||
26366 | @smallexample | |
594fe323 | 26367 | (gdb) |
ef21caaf NR |
26368 | -inferior-tty-set /dev/pts/1 |
26369 | ^done | |
594fe323 | 26370 | (gdb) |
ef21caaf NR |
26371 | @end smallexample |
26372 | ||
26373 | @subheading The @code{-inferior-tty-show} Command | |
26374 | @findex -inferior-tty-show | |
26375 | ||
26376 | @subheading Synopsis | |
26377 | ||
26378 | @smallexample | |
26379 | -inferior-tty-show | |
26380 | @end smallexample | |
26381 | ||
26382 | Show terminal for future runs of program being debugged. | |
26383 | ||
26384 | @subheading @value{GDBN} Command | |
26385 | ||
26386 | The corresponding @value{GDBN} command is @samp{show inferior-tty}. | |
26387 | ||
26388 | @subheading Example | |
26389 | ||
26390 | @smallexample | |
594fe323 | 26391 | (gdb) |
ef21caaf NR |
26392 | -inferior-tty-set /dev/pts/1 |
26393 | ^done | |
594fe323 | 26394 | (gdb) |
ef21caaf NR |
26395 | -inferior-tty-show |
26396 | ^done,inferior_tty_terminal="/dev/pts/1" | |
594fe323 | 26397 | (gdb) |
ef21caaf | 26398 | @end smallexample |
922fbb7b | 26399 | |
a4eefcd8 NR |
26400 | @subheading The @code{-enable-timings} Command |
26401 | @findex -enable-timings | |
26402 | ||
26403 | @subheading Synopsis | |
26404 | ||
26405 | @smallexample | |
26406 | -enable-timings [yes | no] | |
26407 | @end smallexample | |
26408 | ||
26409 | Toggle the printing of the wallclock, user and system times for an MI | |
26410 | command as a field in its output. This command is to help frontend | |
26411 | developers optimize the performance of their code. No argument is | |
26412 | equivalent to @samp{yes}. | |
26413 | ||
26414 | @subheading @value{GDBN} Command | |
26415 | ||
26416 | No equivalent. | |
26417 | ||
26418 | @subheading Example | |
26419 | ||
26420 | @smallexample | |
26421 | (gdb) | |
26422 | -enable-timings | |
26423 | ^done | |
26424 | (gdb) | |
26425 | -break-insert main | |
26426 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
26427 | addr="0x080484ed",func="main",file="myprog.c", | |
26428 | fullname="/home/nickrob/myprog.c",line="73",times="0"@}, | |
26429 | time=@{wallclock="0.05185",user="0.00800",system="0.00000"@} | |
26430 | (gdb) | |
26431 | -enable-timings no | |
26432 | ^done | |
26433 | (gdb) | |
26434 | -exec-run | |
26435 | ^running | |
26436 | (gdb) | |
a47ec5fe | 26437 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",thread-id="0", |
a4eefcd8 NR |
26438 | frame=@{addr="0x080484ed",func="main",args=[@{name="argc",value="1"@}, |
26439 | @{name="argv",value="0xbfb60364"@}],file="myprog.c", | |
26440 | fullname="/home/nickrob/myprog.c",line="73"@} | |
26441 | (gdb) | |
26442 | @end smallexample | |
26443 | ||
922fbb7b AC |
26444 | @node Annotations |
26445 | @chapter @value{GDBN} Annotations | |
26446 | ||
086432e2 AC |
26447 | This chapter describes annotations in @value{GDBN}. Annotations were |
26448 | designed to interface @value{GDBN} to graphical user interfaces or other | |
26449 | similar programs which want to interact with @value{GDBN} at a | |
922fbb7b AC |
26450 | relatively high level. |
26451 | ||
d3e8051b | 26452 | The annotation mechanism has largely been superseded by @sc{gdb/mi} |
086432e2 AC |
26453 | (@pxref{GDB/MI}). |
26454 | ||
922fbb7b AC |
26455 | @ignore |
26456 | This is Edition @value{EDITION}, @value{DATE}. | |
26457 | @end ignore | |
26458 | ||
26459 | @menu | |
26460 | * Annotations Overview:: What annotations are; the general syntax. | |
9e6c4bd5 | 26461 | * Server Prefix:: Issuing a command without affecting user state. |
922fbb7b AC |
26462 | * Prompting:: Annotations marking @value{GDBN}'s need for input. |
26463 | * Errors:: Annotations for error messages. | |
922fbb7b AC |
26464 | * Invalidation:: Some annotations describe things now invalid. |
26465 | * Annotations for Running:: | |
26466 | Whether the program is running, how it stopped, etc. | |
26467 | * Source Annotations:: Annotations describing source code. | |
922fbb7b AC |
26468 | @end menu |
26469 | ||
26470 | @node Annotations Overview | |
26471 | @section What is an Annotation? | |
26472 | @cindex annotations | |
26473 | ||
922fbb7b AC |
26474 | Annotations start with a newline character, two @samp{control-z} |
26475 | characters, and the name of the annotation. If there is no additional | |
26476 | information associated with this annotation, the name of the annotation | |
26477 | is followed immediately by a newline. If there is additional | |
26478 | information, the name of the annotation is followed by a space, the | |
26479 | additional information, and a newline. The additional information | |
26480 | cannot contain newline characters. | |
26481 | ||
26482 | Any output not beginning with a newline and two @samp{control-z} | |
26483 | characters denotes literal output from @value{GDBN}. Currently there is | |
26484 | no need for @value{GDBN} to output a newline followed by two | |
26485 | @samp{control-z} characters, but if there was such a need, the | |
26486 | annotations could be extended with an @samp{escape} annotation which | |
26487 | means those three characters as output. | |
26488 | ||
086432e2 AC |
26489 | The annotation @var{level}, which is specified using the |
26490 | @option{--annotate} command line option (@pxref{Mode Options}), controls | |
26491 | how much information @value{GDBN} prints together with its prompt, | |
26492 | values of expressions, source lines, and other types of output. Level 0 | |
d3e8051b | 26493 | is for no annotations, level 1 is for use when @value{GDBN} is run as a |
086432e2 AC |
26494 | subprocess of @sc{gnu} Emacs, level 3 is the maximum annotation suitable |
26495 | for programs that control @value{GDBN}, and level 2 annotations have | |
26496 | been made obsolete (@pxref{Limitations, , Limitations of the Annotation | |
09d4efe1 EZ |
26497 | Interface, annotate, GDB's Obsolete Annotations}). |
26498 | ||
26499 | @table @code | |
26500 | @kindex set annotate | |
26501 | @item set annotate @var{level} | |
e09f16f9 | 26502 | The @value{GDBN} command @code{set annotate} sets the level of |
09d4efe1 | 26503 | annotations to the specified @var{level}. |
9c16f35a EZ |
26504 | |
26505 | @item show annotate | |
26506 | @kindex show annotate | |
26507 | Show the current annotation level. | |
09d4efe1 EZ |
26508 | @end table |
26509 | ||
26510 | This chapter describes level 3 annotations. | |
086432e2 | 26511 | |
922fbb7b AC |
26512 | A simple example of starting up @value{GDBN} with annotations is: |
26513 | ||
26514 | @smallexample | |
086432e2 AC |
26515 | $ @kbd{gdb --annotate=3} |
26516 | GNU gdb 6.0 | |
26517 | Copyright 2003 Free Software Foundation, Inc. | |
922fbb7b AC |
26518 | GDB is free software, covered by the GNU General Public License, |
26519 | and you are welcome to change it and/or distribute copies of it | |
26520 | under certain conditions. | |
26521 | Type "show copying" to see the conditions. | |
26522 | There is absolutely no warranty for GDB. Type "show warranty" | |
26523 | for details. | |
086432e2 | 26524 | This GDB was configured as "i386-pc-linux-gnu" |
922fbb7b AC |
26525 | |
26526 | ^Z^Zpre-prompt | |
f7dc1244 | 26527 | (@value{GDBP}) |
922fbb7b | 26528 | ^Z^Zprompt |
086432e2 | 26529 | @kbd{quit} |
922fbb7b AC |
26530 | |
26531 | ^Z^Zpost-prompt | |
b383017d | 26532 | $ |
922fbb7b AC |
26533 | @end smallexample |
26534 | ||
26535 | Here @samp{quit} is input to @value{GDBN}; the rest is output from | |
26536 | @value{GDBN}. The three lines beginning @samp{^Z^Z} (where @samp{^Z} | |
26537 | denotes a @samp{control-z} character) are annotations; the rest is | |
26538 | output from @value{GDBN}. | |
26539 | ||
9e6c4bd5 NR |
26540 | @node Server Prefix |
26541 | @section The Server Prefix | |
26542 | @cindex server prefix | |
26543 | ||
26544 | If you prefix a command with @samp{server } then it will not affect | |
26545 | the command history, nor will it affect @value{GDBN}'s notion of which | |
26546 | command to repeat if @key{RET} is pressed on a line by itself. This | |
26547 | means that commands can be run behind a user's back by a front-end in | |
26548 | a transparent manner. | |
26549 | ||
d837706a NR |
26550 | The @code{server } prefix does not affect the recording of values into |
26551 | the value history; to print a value without recording it into the | |
26552 | value history, use the @code{output} command instead of the | |
26553 | @code{print} command. | |
26554 | ||
26555 | Using this prefix also disables confirmation requests | |
26556 | (@pxref{confirmation requests}). | |
9e6c4bd5 | 26557 | |
922fbb7b AC |
26558 | @node Prompting |
26559 | @section Annotation for @value{GDBN} Input | |
26560 | ||
26561 | @cindex annotations for prompts | |
26562 | When @value{GDBN} prompts for input, it annotates this fact so it is possible | |
26563 | to know when to send output, when the output from a given command is | |
26564 | over, etc. | |
26565 | ||
26566 | Different kinds of input each have a different @dfn{input type}. Each | |
26567 | input type has three annotations: a @code{pre-} annotation, which | |
26568 | denotes the beginning of any prompt which is being output, a plain | |
26569 | annotation, which denotes the end of the prompt, and then a @code{post-} | |
26570 | annotation which denotes the end of any echo which may (or may not) be | |
26571 | associated with the input. For example, the @code{prompt} input type | |
26572 | features the following annotations: | |
26573 | ||
26574 | @smallexample | |
26575 | ^Z^Zpre-prompt | |
26576 | ^Z^Zprompt | |
26577 | ^Z^Zpost-prompt | |
26578 | @end smallexample | |
26579 | ||
26580 | The input types are | |
26581 | ||
26582 | @table @code | |
e5ac9b53 EZ |
26583 | @findex pre-prompt annotation |
26584 | @findex prompt annotation | |
26585 | @findex post-prompt annotation | |
922fbb7b AC |
26586 | @item prompt |
26587 | When @value{GDBN} is prompting for a command (the main @value{GDBN} prompt). | |
26588 | ||
e5ac9b53 EZ |
26589 | @findex pre-commands annotation |
26590 | @findex commands annotation | |
26591 | @findex post-commands annotation | |
922fbb7b AC |
26592 | @item commands |
26593 | When @value{GDBN} prompts for a set of commands, like in the @code{commands} | |
26594 | command. The annotations are repeated for each command which is input. | |
26595 | ||
e5ac9b53 EZ |
26596 | @findex pre-overload-choice annotation |
26597 | @findex overload-choice annotation | |
26598 | @findex post-overload-choice annotation | |
922fbb7b AC |
26599 | @item overload-choice |
26600 | When @value{GDBN} wants the user to select between various overloaded functions. | |
26601 | ||
e5ac9b53 EZ |
26602 | @findex pre-query annotation |
26603 | @findex query annotation | |
26604 | @findex post-query annotation | |
922fbb7b AC |
26605 | @item query |
26606 | When @value{GDBN} wants the user to confirm a potentially dangerous operation. | |
26607 | ||
e5ac9b53 EZ |
26608 | @findex pre-prompt-for-continue annotation |
26609 | @findex prompt-for-continue annotation | |
26610 | @findex post-prompt-for-continue annotation | |
922fbb7b AC |
26611 | @item prompt-for-continue |
26612 | When @value{GDBN} is asking the user to press return to continue. Note: Don't | |
26613 | expect this to work well; instead use @code{set height 0} to disable | |
26614 | prompting. This is because the counting of lines is buggy in the | |
26615 | presence of annotations. | |
26616 | @end table | |
26617 | ||
26618 | @node Errors | |
26619 | @section Errors | |
26620 | @cindex annotations for errors, warnings and interrupts | |
26621 | ||
e5ac9b53 | 26622 | @findex quit annotation |
922fbb7b AC |
26623 | @smallexample |
26624 | ^Z^Zquit | |
26625 | @end smallexample | |
26626 | ||
26627 | This annotation occurs right before @value{GDBN} responds to an interrupt. | |
26628 | ||
e5ac9b53 | 26629 | @findex error annotation |
922fbb7b AC |
26630 | @smallexample |
26631 | ^Z^Zerror | |
26632 | @end smallexample | |
26633 | ||
26634 | This annotation occurs right before @value{GDBN} responds to an error. | |
26635 | ||
26636 | Quit and error annotations indicate that any annotations which @value{GDBN} was | |
26637 | in the middle of may end abruptly. For example, if a | |
26638 | @code{value-history-begin} annotation is followed by a @code{error}, one | |
26639 | cannot expect to receive the matching @code{value-history-end}. One | |
26640 | cannot expect not to receive it either, however; an error annotation | |
26641 | does not necessarily mean that @value{GDBN} is immediately returning all the way | |
26642 | to the top level. | |
26643 | ||
e5ac9b53 | 26644 | @findex error-begin annotation |
922fbb7b AC |
26645 | A quit or error annotation may be preceded by |
26646 | ||
26647 | @smallexample | |
26648 | ^Z^Zerror-begin | |
26649 | @end smallexample | |
26650 | ||
26651 | Any output between that and the quit or error annotation is the error | |
26652 | message. | |
26653 | ||
26654 | Warning messages are not yet annotated. | |
26655 | @c If we want to change that, need to fix warning(), type_error(), | |
26656 | @c range_error(), and possibly other places. | |
26657 | ||
922fbb7b AC |
26658 | @node Invalidation |
26659 | @section Invalidation Notices | |
26660 | ||
26661 | @cindex annotations for invalidation messages | |
26662 | The following annotations say that certain pieces of state may have | |
26663 | changed. | |
26664 | ||
26665 | @table @code | |
e5ac9b53 | 26666 | @findex frames-invalid annotation |
922fbb7b AC |
26667 | @item ^Z^Zframes-invalid |
26668 | ||
26669 | The frames (for example, output from the @code{backtrace} command) may | |
26670 | have changed. | |
26671 | ||
e5ac9b53 | 26672 | @findex breakpoints-invalid annotation |
922fbb7b AC |
26673 | @item ^Z^Zbreakpoints-invalid |
26674 | ||
26675 | The breakpoints may have changed. For example, the user just added or | |
26676 | deleted a breakpoint. | |
26677 | @end table | |
26678 | ||
26679 | @node Annotations for Running | |
26680 | @section Running the Program | |
26681 | @cindex annotations for running programs | |
26682 | ||
e5ac9b53 EZ |
26683 | @findex starting annotation |
26684 | @findex stopping annotation | |
922fbb7b | 26685 | When the program starts executing due to a @value{GDBN} command such as |
b383017d | 26686 | @code{step} or @code{continue}, |
922fbb7b AC |
26687 | |
26688 | @smallexample | |
26689 | ^Z^Zstarting | |
26690 | @end smallexample | |
26691 | ||
b383017d | 26692 | is output. When the program stops, |
922fbb7b AC |
26693 | |
26694 | @smallexample | |
26695 | ^Z^Zstopped | |
26696 | @end smallexample | |
26697 | ||
26698 | is output. Before the @code{stopped} annotation, a variety of | |
26699 | annotations describe how the program stopped. | |
26700 | ||
26701 | @table @code | |
e5ac9b53 | 26702 | @findex exited annotation |
922fbb7b AC |
26703 | @item ^Z^Zexited @var{exit-status} |
26704 | The program exited, and @var{exit-status} is the exit status (zero for | |
26705 | successful exit, otherwise nonzero). | |
26706 | ||
e5ac9b53 EZ |
26707 | @findex signalled annotation |
26708 | @findex signal-name annotation | |
26709 | @findex signal-name-end annotation | |
26710 | @findex signal-string annotation | |
26711 | @findex signal-string-end annotation | |
922fbb7b AC |
26712 | @item ^Z^Zsignalled |
26713 | The program exited with a signal. After the @code{^Z^Zsignalled}, the | |
26714 | annotation continues: | |
26715 | ||
26716 | @smallexample | |
26717 | @var{intro-text} | |
26718 | ^Z^Zsignal-name | |
26719 | @var{name} | |
26720 | ^Z^Zsignal-name-end | |
26721 | @var{middle-text} | |
26722 | ^Z^Zsignal-string | |
26723 | @var{string} | |
26724 | ^Z^Zsignal-string-end | |
26725 | @var{end-text} | |
26726 | @end smallexample | |
26727 | ||
26728 | @noindent | |
26729 | where @var{name} is the name of the signal, such as @code{SIGILL} or | |
26730 | @code{SIGSEGV}, and @var{string} is the explanation of the signal, such | |
26731 | as @code{Illegal Instruction} or @code{Segmentation fault}. | |
26732 | @var{intro-text}, @var{middle-text}, and @var{end-text} are for the | |
26733 | user's benefit and have no particular format. | |
26734 | ||
e5ac9b53 | 26735 | @findex signal annotation |
922fbb7b AC |
26736 | @item ^Z^Zsignal |
26737 | The syntax of this annotation is just like @code{signalled}, but @value{GDBN} is | |
26738 | just saying that the program received the signal, not that it was | |
26739 | terminated with it. | |
26740 | ||
e5ac9b53 | 26741 | @findex breakpoint annotation |
922fbb7b AC |
26742 | @item ^Z^Zbreakpoint @var{number} |
26743 | The program hit breakpoint number @var{number}. | |
26744 | ||
e5ac9b53 | 26745 | @findex watchpoint annotation |
922fbb7b AC |
26746 | @item ^Z^Zwatchpoint @var{number} |
26747 | The program hit watchpoint number @var{number}. | |
26748 | @end table | |
26749 | ||
26750 | @node Source Annotations | |
26751 | @section Displaying Source | |
26752 | @cindex annotations for source display | |
26753 | ||
e5ac9b53 | 26754 | @findex source annotation |
922fbb7b AC |
26755 | The following annotation is used instead of displaying source code: |
26756 | ||
26757 | @smallexample | |
26758 | ^Z^Zsource @var{filename}:@var{line}:@var{character}:@var{middle}:@var{addr} | |
26759 | @end smallexample | |
26760 | ||
26761 | where @var{filename} is an absolute file name indicating which source | |
26762 | file, @var{line} is the line number within that file (where 1 is the | |
26763 | first line in the file), @var{character} is the character position | |
26764 | within the file (where 0 is the first character in the file) (for most | |
26765 | debug formats this will necessarily point to the beginning of a line), | |
26766 | @var{middle} is @samp{middle} if @var{addr} is in the middle of the | |
26767 | line, or @samp{beg} if @var{addr} is at the beginning of the line, and | |
26768 | @var{addr} is the address in the target program associated with the | |
26769 | source which is being displayed. @var{addr} is in the form @samp{0x} | |
26770 | followed by one or more lowercase hex digits (note that this does not | |
26771 | depend on the language). | |
26772 | ||
4efc6507 DE |
26773 | @node JIT Interface |
26774 | @chapter JIT Compilation Interface | |
26775 | @cindex just-in-time compilation | |
26776 | @cindex JIT compilation interface | |
26777 | ||
26778 | This chapter documents @value{GDBN}'s @dfn{just-in-time} (JIT) compilation | |
26779 | interface. A JIT compiler is a program or library that generates native | |
26780 | executable code at runtime and executes it, usually in order to achieve good | |
26781 | performance while maintaining platform independence. | |
26782 | ||
26783 | Programs that use JIT compilation are normally difficult to debug because | |
26784 | portions of their code are generated at runtime, instead of being loaded from | |
26785 | object files, which is where @value{GDBN} normally finds the program's symbols | |
26786 | and debug information. In order to debug programs that use JIT compilation, | |
26787 | @value{GDBN} has an interface that allows the program to register in-memory | |
26788 | symbol files with @value{GDBN} at runtime. | |
26789 | ||
26790 | If you are using @value{GDBN} to debug a program that uses this interface, then | |
26791 | it should work transparently so long as you have not stripped the binary. If | |
26792 | you are developing a JIT compiler, then the interface is documented in the rest | |
26793 | of this chapter. At this time, the only known client of this interface is the | |
26794 | LLVM JIT. | |
26795 | ||
26796 | Broadly speaking, the JIT interface mirrors the dynamic loader interface. The | |
26797 | JIT compiler communicates with @value{GDBN} by writing data into a global | |
26798 | variable and calling a fuction at a well-known symbol. When @value{GDBN} | |
26799 | attaches, it reads a linked list of symbol files from the global variable to | |
26800 | find existing code, and puts a breakpoint in the function so that it can find | |
26801 | out about additional code. | |
26802 | ||
26803 | @menu | |
26804 | * Declarations:: Relevant C struct declarations | |
26805 | * Registering Code:: Steps to register code | |
26806 | * Unregistering Code:: Steps to unregister code | |
26807 | @end menu | |
26808 | ||
26809 | @node Declarations | |
26810 | @section JIT Declarations | |
26811 | ||
26812 | These are the relevant struct declarations that a C program should include to | |
26813 | implement the interface: | |
26814 | ||
26815 | @smallexample | |
26816 | typedef enum | |
26817 | @{ | |
26818 | JIT_NOACTION = 0, | |
26819 | JIT_REGISTER_FN, | |
26820 | JIT_UNREGISTER_FN | |
26821 | @} jit_actions_t; | |
26822 | ||
26823 | struct jit_code_entry | |
26824 | @{ | |
26825 | struct jit_code_entry *next_entry; | |
26826 | struct jit_code_entry *prev_entry; | |
26827 | const char *symfile_addr; | |
26828 | uint64_t symfile_size; | |
26829 | @}; | |
26830 | ||
26831 | struct jit_descriptor | |
26832 | @{ | |
26833 | uint32_t version; | |
26834 | /* This type should be jit_actions_t, but we use uint32_t | |
26835 | to be explicit about the bitwidth. */ | |
26836 | uint32_t action_flag; | |
26837 | struct jit_code_entry *relevant_entry; | |
26838 | struct jit_code_entry *first_entry; | |
26839 | @}; | |
26840 | ||
26841 | /* GDB puts a breakpoint in this function. */ | |
26842 | void __attribute__((noinline)) __jit_debug_register_code() @{ @}; | |
26843 | ||
26844 | /* Make sure to specify the version statically, because the | |
26845 | debugger may check the version before we can set it. */ | |
26846 | struct jit_descriptor __jit_debug_descriptor = @{ 1, 0, 0, 0 @}; | |
26847 | @end smallexample | |
26848 | ||
26849 | If the JIT is multi-threaded, then it is important that the JIT synchronize any | |
26850 | modifications to this global data properly, which can easily be done by putting | |
26851 | a global mutex around modifications to these structures. | |
26852 | ||
26853 | @node Registering Code | |
26854 | @section Registering Code | |
26855 | ||
26856 | To register code with @value{GDBN}, the JIT should follow this protocol: | |
26857 | ||
26858 | @itemize @bullet | |
26859 | @item | |
26860 | Generate an object file in memory with symbols and other desired debug | |
26861 | information. The file must include the virtual addresses of the sections. | |
26862 | ||
26863 | @item | |
26864 | Create a code entry for the file, which gives the start and size of the symbol | |
26865 | file. | |
26866 | ||
26867 | @item | |
26868 | Add it to the linked list in the JIT descriptor. | |
26869 | ||
26870 | @item | |
26871 | Point the relevant_entry field of the descriptor at the entry. | |
26872 | ||
26873 | @item | |
26874 | Set @code{action_flag} to @code{JIT_REGISTER} and call | |
26875 | @code{__jit_debug_register_code}. | |
26876 | @end itemize | |
26877 | ||
26878 | When @value{GDBN} is attached and the breakpoint fires, @value{GDBN} uses the | |
26879 | @code{relevant_entry} pointer so it doesn't have to walk the list looking for | |
26880 | new code. However, the linked list must still be maintained in order to allow | |
26881 | @value{GDBN} to attach to a running process and still find the symbol files. | |
26882 | ||
26883 | @node Unregistering Code | |
26884 | @section Unregistering Code | |
26885 | ||
26886 | If code is freed, then the JIT should use the following protocol: | |
26887 | ||
26888 | @itemize @bullet | |
26889 | @item | |
26890 | Remove the code entry corresponding to the code from the linked list. | |
26891 | ||
26892 | @item | |
26893 | Point the @code{relevant_entry} field of the descriptor at the code entry. | |
26894 | ||
26895 | @item | |
26896 | Set @code{action_flag} to @code{JIT_UNREGISTER} and call | |
26897 | @code{__jit_debug_register_code}. | |
26898 | @end itemize | |
26899 | ||
26900 | If the JIT frees or recompiles code without unregistering it, then @value{GDBN} | |
26901 | and the JIT will leak the memory used for the associated symbol files. | |
26902 | ||
8e04817f AC |
26903 | @node GDB Bugs |
26904 | @chapter Reporting Bugs in @value{GDBN} | |
26905 | @cindex bugs in @value{GDBN} | |
26906 | @cindex reporting bugs in @value{GDBN} | |
c906108c | 26907 | |
8e04817f | 26908 | Your bug reports play an essential role in making @value{GDBN} reliable. |
c906108c | 26909 | |
8e04817f AC |
26910 | Reporting a bug may help you by bringing a solution to your problem, or it |
26911 | may not. But in any case the principal function of a bug report is to help | |
26912 | the entire community by making the next version of @value{GDBN} work better. Bug | |
26913 | reports are your contribution to the maintenance of @value{GDBN}. | |
c906108c | 26914 | |
8e04817f AC |
26915 | In order for a bug report to serve its purpose, you must include the |
26916 | information that enables us to fix the bug. | |
c4555f82 SC |
26917 | |
26918 | @menu | |
8e04817f AC |
26919 | * Bug Criteria:: Have you found a bug? |
26920 | * Bug Reporting:: How to report bugs | |
c4555f82 SC |
26921 | @end menu |
26922 | ||
8e04817f | 26923 | @node Bug Criteria |
79a6e687 | 26924 | @section Have You Found a Bug? |
8e04817f | 26925 | @cindex bug criteria |
c4555f82 | 26926 | |
8e04817f | 26927 | If you are not sure whether you have found a bug, here are some guidelines: |
c4555f82 SC |
26928 | |
26929 | @itemize @bullet | |
8e04817f AC |
26930 | @cindex fatal signal |
26931 | @cindex debugger crash | |
26932 | @cindex crash of debugger | |
c4555f82 | 26933 | @item |
8e04817f AC |
26934 | If the debugger gets a fatal signal, for any input whatever, that is a |
26935 | @value{GDBN} bug. Reliable debuggers never crash. | |
26936 | ||
26937 | @cindex error on valid input | |
26938 | @item | |
26939 | If @value{GDBN} produces an error message for valid input, that is a | |
26940 | bug. (Note that if you're cross debugging, the problem may also be | |
26941 | somewhere in the connection to the target.) | |
c4555f82 | 26942 | |
8e04817f | 26943 | @cindex invalid input |
c4555f82 | 26944 | @item |
8e04817f AC |
26945 | If @value{GDBN} does not produce an error message for invalid input, |
26946 | that is a bug. However, you should note that your idea of | |
26947 | ``invalid input'' might be our idea of ``an extension'' or ``support | |
26948 | for traditional practice''. | |
26949 | ||
26950 | @item | |
26951 | If you are an experienced user of debugging tools, your suggestions | |
26952 | for improvement of @value{GDBN} are welcome in any case. | |
c4555f82 SC |
26953 | @end itemize |
26954 | ||
8e04817f | 26955 | @node Bug Reporting |
79a6e687 | 26956 | @section How to Report Bugs |
8e04817f AC |
26957 | @cindex bug reports |
26958 | @cindex @value{GDBN} bugs, reporting | |
26959 | ||
26960 | A number of companies and individuals offer support for @sc{gnu} products. | |
26961 | If you obtained @value{GDBN} from a support organization, we recommend you | |
26962 | contact that organization first. | |
26963 | ||
26964 | You can find contact information for many support companies and | |
26965 | individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs | |
26966 | distribution. | |
26967 | @c should add a web page ref... | |
26968 | ||
c16158bc JM |
26969 | @ifset BUGURL |
26970 | @ifset BUGURL_DEFAULT | |
129188f6 | 26971 | In any event, we also recommend that you submit bug reports for |
d3e8051b | 26972 | @value{GDBN}. The preferred method is to submit them directly using |
129188f6 AC |
26973 | @uref{http://www.gnu.org/software/gdb/bugs/, @value{GDBN}'s Bugs web |
26974 | page}. Alternatively, the @email{bug-gdb@@gnu.org, e-mail gateway} can | |
26975 | be used. | |
8e04817f AC |
26976 | |
26977 | @strong{Do not send bug reports to @samp{info-gdb}, or to | |
26978 | @samp{help-gdb}, or to any newsgroups.} Most users of @value{GDBN} do | |
26979 | not want to receive bug reports. Those that do have arranged to receive | |
26980 | @samp{bug-gdb}. | |
26981 | ||
26982 | The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which | |
26983 | serves as a repeater. The mailing list and the newsgroup carry exactly | |
26984 | the same messages. Often people think of posting bug reports to the | |
26985 | newsgroup instead of mailing them. This appears to work, but it has one | |
26986 | problem which can be crucial: a newsgroup posting often lacks a mail | |
26987 | path back to the sender. Thus, if we need to ask for more information, | |
26988 | we may be unable to reach you. For this reason, it is better to send | |
26989 | bug reports to the mailing list. | |
c16158bc JM |
26990 | @end ifset |
26991 | @ifclear BUGURL_DEFAULT | |
26992 | In any event, we also recommend that you submit bug reports for | |
26993 | @value{GDBN} to @value{BUGURL}. | |
26994 | @end ifclear | |
26995 | @end ifset | |
c4555f82 | 26996 | |
8e04817f AC |
26997 | The fundamental principle of reporting bugs usefully is this: |
26998 | @strong{report all the facts}. If you are not sure whether to state a | |
26999 | fact or leave it out, state it! | |
c4555f82 | 27000 | |
8e04817f AC |
27001 | Often people omit facts because they think they know what causes the |
27002 | problem and assume that some details do not matter. Thus, you might | |
27003 | assume that the name of the variable you use in an example does not matter. | |
27004 | Well, probably it does not, but one cannot be sure. Perhaps the bug is a | |
27005 | stray memory reference which happens to fetch from the location where that | |
27006 | name is stored in memory; perhaps, if the name were different, the contents | |
27007 | of that location would fool the debugger into doing the right thing despite | |
27008 | the bug. Play it safe and give a specific, complete example. That is the | |
27009 | easiest thing for you to do, and the most helpful. | |
c4555f82 | 27010 | |
8e04817f AC |
27011 | Keep in mind that the purpose of a bug report is to enable us to fix the |
27012 | bug. It may be that the bug has been reported previously, but neither | |
27013 | you nor we can know that unless your bug report is complete and | |
27014 | self-contained. | |
c4555f82 | 27015 | |
8e04817f AC |
27016 | Sometimes people give a few sketchy facts and ask, ``Does this ring a |
27017 | bell?'' Those bug reports are useless, and we urge everyone to | |
27018 | @emph{refuse to respond to them} except to chide the sender to report | |
27019 | bugs properly. | |
27020 | ||
27021 | To enable us to fix the bug, you should include all these things: | |
c4555f82 SC |
27022 | |
27023 | @itemize @bullet | |
27024 | @item | |
8e04817f AC |
27025 | The version of @value{GDBN}. @value{GDBN} announces it if you start |
27026 | with no arguments; you can also print it at any time using @code{show | |
27027 | version}. | |
c4555f82 | 27028 | |
8e04817f AC |
27029 | Without this, we will not know whether there is any point in looking for |
27030 | the bug in the current version of @value{GDBN}. | |
c4555f82 SC |
27031 | |
27032 | @item | |
8e04817f AC |
27033 | The type of machine you are using, and the operating system name and |
27034 | version number. | |
c4555f82 SC |
27035 | |
27036 | @item | |
c1468174 | 27037 | What compiler (and its version) was used to compile @value{GDBN}---e.g.@: |
8e04817f | 27038 | ``@value{GCC}--2.8.1''. |
c4555f82 SC |
27039 | |
27040 | @item | |
8e04817f | 27041 | What compiler (and its version) was used to compile the program you are |
c1468174 | 27042 | debugging---e.g.@: ``@value{GCC}--2.8.1'', or ``HP92453-01 A.10.32.03 HP |
3f94c067 BW |
27043 | C Compiler''. For @value{NGCC}, you can say @kbd{@value{GCC} --version} |
27044 | to get this information; for other compilers, see the documentation for | |
27045 | those compilers. | |
c4555f82 | 27046 | |
8e04817f AC |
27047 | @item |
27048 | The command arguments you gave the compiler to compile your example and | |
27049 | observe the bug. For example, did you use @samp{-O}? To guarantee | |
27050 | you will not omit something important, list them all. A copy of the | |
27051 | Makefile (or the output from make) is sufficient. | |
c4555f82 | 27052 | |
8e04817f AC |
27053 | If we were to try to guess the arguments, we would probably guess wrong |
27054 | and then we might not encounter the bug. | |
c4555f82 | 27055 | |
8e04817f AC |
27056 | @item |
27057 | A complete input script, and all necessary source files, that will | |
27058 | reproduce the bug. | |
c4555f82 | 27059 | |
8e04817f AC |
27060 | @item |
27061 | A description of what behavior you observe that you believe is | |
27062 | incorrect. For example, ``It gets a fatal signal.'' | |
c4555f82 | 27063 | |
8e04817f AC |
27064 | Of course, if the bug is that @value{GDBN} gets a fatal signal, then we |
27065 | will certainly notice it. But if the bug is incorrect output, we might | |
27066 | not notice unless it is glaringly wrong. You might as well not give us | |
27067 | a chance to make a mistake. | |
c4555f82 | 27068 | |
8e04817f AC |
27069 | Even if the problem you experience is a fatal signal, you should still |
27070 | say so explicitly. Suppose something strange is going on, such as, your | |
27071 | copy of @value{GDBN} is out of synch, or you have encountered a bug in | |
27072 | the C library on your system. (This has happened!) Your copy might | |
27073 | crash and ours would not. If you told us to expect a crash, then when | |
27074 | ours fails to crash, we would know that the bug was not happening for | |
27075 | us. If you had not told us to expect a crash, then we would not be able | |
27076 | to draw any conclusion from our observations. | |
c4555f82 | 27077 | |
e0c07bf0 MC |
27078 | @pindex script |
27079 | @cindex recording a session script | |
27080 | To collect all this information, you can use a session recording program | |
27081 | such as @command{script}, which is available on many Unix systems. | |
27082 | Just run your @value{GDBN} session inside @command{script} and then | |
27083 | include the @file{typescript} file with your bug report. | |
27084 | ||
27085 | Another way to record a @value{GDBN} session is to run @value{GDBN} | |
27086 | inside Emacs and then save the entire buffer to a file. | |
27087 | ||
8e04817f AC |
27088 | @item |
27089 | If you wish to suggest changes to the @value{GDBN} source, send us context | |
27090 | diffs. If you even discuss something in the @value{GDBN} source, refer to | |
27091 | it by context, not by line number. | |
c4555f82 | 27092 | |
8e04817f AC |
27093 | The line numbers in our development sources will not match those in your |
27094 | sources. Your line numbers would convey no useful information to us. | |
c4555f82 | 27095 | |
8e04817f | 27096 | @end itemize |
c4555f82 | 27097 | |
8e04817f | 27098 | Here are some things that are not necessary: |
c4555f82 | 27099 | |
8e04817f AC |
27100 | @itemize @bullet |
27101 | @item | |
27102 | A description of the envelope of the bug. | |
c4555f82 | 27103 | |
8e04817f AC |
27104 | Often people who encounter a bug spend a lot of time investigating |
27105 | which changes to the input file will make the bug go away and which | |
27106 | changes will not affect it. | |
c4555f82 | 27107 | |
8e04817f AC |
27108 | This is often time consuming and not very useful, because the way we |
27109 | will find the bug is by running a single example under the debugger | |
27110 | with breakpoints, not by pure deduction from a series of examples. | |
27111 | We recommend that you save your time for something else. | |
c4555f82 | 27112 | |
8e04817f AC |
27113 | Of course, if you can find a simpler example to report @emph{instead} |
27114 | of the original one, that is a convenience for us. Errors in the | |
27115 | output will be easier to spot, running under the debugger will take | |
27116 | less time, and so on. | |
c4555f82 | 27117 | |
8e04817f AC |
27118 | However, simplification is not vital; if you do not want to do this, |
27119 | report the bug anyway and send us the entire test case you used. | |
c4555f82 | 27120 | |
8e04817f AC |
27121 | @item |
27122 | A patch for the bug. | |
c4555f82 | 27123 | |
8e04817f AC |
27124 | A patch for the bug does help us if it is a good one. But do not omit |
27125 | the necessary information, such as the test case, on the assumption that | |
27126 | a patch is all we need. We might see problems with your patch and decide | |
27127 | to fix the problem another way, or we might not understand it at all. | |
c4555f82 | 27128 | |
8e04817f AC |
27129 | Sometimes with a program as complicated as @value{GDBN} it is very hard to |
27130 | construct an example that will make the program follow a certain path | |
27131 | through the code. If you do not send us the example, we will not be able | |
27132 | to construct one, so we will not be able to verify that the bug is fixed. | |
c4555f82 | 27133 | |
8e04817f AC |
27134 | And if we cannot understand what bug you are trying to fix, or why your |
27135 | patch should be an improvement, we will not install it. A test case will | |
27136 | help us to understand. | |
c4555f82 | 27137 | |
8e04817f AC |
27138 | @item |
27139 | A guess about what the bug is or what it depends on. | |
c4555f82 | 27140 | |
8e04817f AC |
27141 | Such guesses are usually wrong. Even we cannot guess right about such |
27142 | things without first using the debugger to find the facts. | |
27143 | @end itemize | |
c4555f82 | 27144 | |
8e04817f AC |
27145 | @c The readline documentation is distributed with the readline code |
27146 | @c and consists of the two following files: | |
27147 | @c rluser.texinfo | |
27148 | @c inc-hist.texinfo | |
27149 | @c Use -I with makeinfo to point to the appropriate directory, | |
27150 | @c environment var TEXINPUTS with TeX. | |
5bdf8622 | 27151 | @include rluser.texi |
8e04817f | 27152 | @include inc-hist.texinfo |
c4555f82 | 27153 | |
c4555f82 | 27154 | |
8e04817f AC |
27155 | @node Formatting Documentation |
27156 | @appendix Formatting Documentation | |
c4555f82 | 27157 | |
8e04817f AC |
27158 | @cindex @value{GDBN} reference card |
27159 | @cindex reference card | |
27160 | The @value{GDBN} 4 release includes an already-formatted reference card, ready | |
27161 | for printing with PostScript or Ghostscript, in the @file{gdb} | |
27162 | subdirectory of the main source directory@footnote{In | |
27163 | @file{gdb-@value{GDBVN}/gdb/refcard.ps} of the version @value{GDBVN} | |
27164 | release.}. If you can use PostScript or Ghostscript with your printer, | |
27165 | you can print the reference card immediately with @file{refcard.ps}. | |
c4555f82 | 27166 | |
8e04817f AC |
27167 | The release also includes the source for the reference card. You |
27168 | can format it, using @TeX{}, by typing: | |
c4555f82 | 27169 | |
474c8240 | 27170 | @smallexample |
8e04817f | 27171 | make refcard.dvi |
474c8240 | 27172 | @end smallexample |
c4555f82 | 27173 | |
8e04817f AC |
27174 | The @value{GDBN} reference card is designed to print in @dfn{landscape} |
27175 | mode on US ``letter'' size paper; | |
27176 | that is, on a sheet 11 inches wide by 8.5 inches | |
27177 | high. You will need to specify this form of printing as an option to | |
27178 | your @sc{dvi} output program. | |
c4555f82 | 27179 | |
8e04817f | 27180 | @cindex documentation |
c4555f82 | 27181 | |
8e04817f AC |
27182 | All the documentation for @value{GDBN} comes as part of the machine-readable |
27183 | distribution. The documentation is written in Texinfo format, which is | |
27184 | a documentation system that uses a single source file to produce both | |
27185 | on-line information and a printed manual. You can use one of the Info | |
27186 | formatting commands to create the on-line version of the documentation | |
27187 | and @TeX{} (or @code{texi2roff}) to typeset the printed version. | |
c4555f82 | 27188 | |
8e04817f AC |
27189 | @value{GDBN} includes an already formatted copy of the on-line Info |
27190 | version of this manual in the @file{gdb} subdirectory. The main Info | |
27191 | file is @file{gdb-@value{GDBVN}/gdb/gdb.info}, and it refers to | |
27192 | subordinate files matching @samp{gdb.info*} in the same directory. If | |
27193 | necessary, you can print out these files, or read them with any editor; | |
27194 | but they are easier to read using the @code{info} subsystem in @sc{gnu} | |
27195 | Emacs or the standalone @code{info} program, available as part of the | |
27196 | @sc{gnu} Texinfo distribution. | |
c4555f82 | 27197 | |
8e04817f AC |
27198 | If you want to format these Info files yourself, you need one of the |
27199 | Info formatting programs, such as @code{texinfo-format-buffer} or | |
27200 | @code{makeinfo}. | |
c4555f82 | 27201 | |
8e04817f AC |
27202 | If you have @code{makeinfo} installed, and are in the top level |
27203 | @value{GDBN} source directory (@file{gdb-@value{GDBVN}}, in the case of | |
27204 | version @value{GDBVN}), you can make the Info file by typing: | |
c4555f82 | 27205 | |
474c8240 | 27206 | @smallexample |
8e04817f AC |
27207 | cd gdb |
27208 | make gdb.info | |
474c8240 | 27209 | @end smallexample |
c4555f82 | 27210 | |
8e04817f AC |
27211 | If you want to typeset and print copies of this manual, you need @TeX{}, |
27212 | a program to print its @sc{dvi} output files, and @file{texinfo.tex}, the | |
27213 | Texinfo definitions file. | |
c4555f82 | 27214 | |
8e04817f AC |
27215 | @TeX{} is a typesetting program; it does not print files directly, but |
27216 | produces output files called @sc{dvi} files. To print a typeset | |
27217 | document, you need a program to print @sc{dvi} files. If your system | |
27218 | has @TeX{} installed, chances are it has such a program. The precise | |
27219 | command to use depends on your system; @kbd{lpr -d} is common; another | |
27220 | (for PostScript devices) is @kbd{dvips}. The @sc{dvi} print command may | |
27221 | require a file name without any extension or a @samp{.dvi} extension. | |
c4555f82 | 27222 | |
8e04817f AC |
27223 | @TeX{} also requires a macro definitions file called |
27224 | @file{texinfo.tex}. This file tells @TeX{} how to typeset a document | |
27225 | written in Texinfo format. On its own, @TeX{} cannot either read or | |
27226 | typeset a Texinfo file. @file{texinfo.tex} is distributed with GDB | |
27227 | and is located in the @file{gdb-@var{version-number}/texinfo} | |
27228 | directory. | |
c4555f82 | 27229 | |
8e04817f | 27230 | If you have @TeX{} and a @sc{dvi} printer program installed, you can |
d3e8051b | 27231 | typeset and print this manual. First switch to the @file{gdb} |
8e04817f AC |
27232 | subdirectory of the main source directory (for example, to |
27233 | @file{gdb-@value{GDBVN}/gdb}) and type: | |
c4555f82 | 27234 | |
474c8240 | 27235 | @smallexample |
8e04817f | 27236 | make gdb.dvi |
474c8240 | 27237 | @end smallexample |
c4555f82 | 27238 | |
8e04817f | 27239 | Then give @file{gdb.dvi} to your @sc{dvi} printing program. |
c4555f82 | 27240 | |
8e04817f AC |
27241 | @node Installing GDB |
27242 | @appendix Installing @value{GDBN} | |
8e04817f | 27243 | @cindex installation |
c4555f82 | 27244 | |
7fa2210b DJ |
27245 | @menu |
27246 | * Requirements:: Requirements for building @value{GDBN} | |
db2e3e2e | 27247 | * Running Configure:: Invoking the @value{GDBN} @file{configure} script |
7fa2210b DJ |
27248 | * Separate Objdir:: Compiling @value{GDBN} in another directory |
27249 | * Config Names:: Specifying names for hosts and targets | |
27250 | * Configure Options:: Summary of options for configure | |
098b41a6 | 27251 | * System-wide configuration:: Having a system-wide init file |
7fa2210b DJ |
27252 | @end menu |
27253 | ||
27254 | @node Requirements | |
79a6e687 | 27255 | @section Requirements for Building @value{GDBN} |
7fa2210b DJ |
27256 | @cindex building @value{GDBN}, requirements for |
27257 | ||
27258 | Building @value{GDBN} requires various tools and packages to be available. | |
27259 | Other packages will be used only if they are found. | |
27260 | ||
79a6e687 | 27261 | @heading Tools/Packages Necessary for Building @value{GDBN} |
7fa2210b DJ |
27262 | @table @asis |
27263 | @item ISO C90 compiler | |
27264 | @value{GDBN} is written in ISO C90. It should be buildable with any | |
27265 | working C90 compiler, e.g.@: GCC. | |
27266 | ||
27267 | @end table | |
27268 | ||
79a6e687 | 27269 | @heading Tools/Packages Optional for Building @value{GDBN} |
7fa2210b DJ |
27270 | @table @asis |
27271 | @item Expat | |
123dc839 | 27272 | @anchor{Expat} |
7fa2210b DJ |
27273 | @value{GDBN} can use the Expat XML parsing library. This library may be |
27274 | included with your operating system distribution; if it is not, you | |
27275 | can get the latest version from @url{http://expat.sourceforge.net}. | |
db2e3e2e | 27276 | The @file{configure} script will search for this library in several |
7fa2210b DJ |
27277 | standard locations; if it is installed in an unusual path, you can |
27278 | use the @option{--with-libexpat-prefix} option to specify its location. | |
27279 | ||
9cceb671 DJ |
27280 | Expat is used for: |
27281 | ||
27282 | @itemize @bullet | |
27283 | @item | |
27284 | Remote protocol memory maps (@pxref{Memory Map Format}) | |
27285 | @item | |
27286 | Target descriptions (@pxref{Target Descriptions}) | |
27287 | @item | |
27288 | Remote shared library lists (@pxref{Library List Format}) | |
27289 | @item | |
27290 | MS-Windows shared libraries (@pxref{Shared Libraries}) | |
27291 | @end itemize | |
7fa2210b | 27292 | |
31fffb02 CS |
27293 | @item zlib |
27294 | @cindex compressed debug sections | |
27295 | @value{GDBN} will use the @samp{zlib} library, if available, to read | |
27296 | compressed debug sections. Some linkers, such as GNU gold, are capable | |
27297 | of producing binaries with compressed debug sections. If @value{GDBN} | |
27298 | is compiled with @samp{zlib}, it will be able to read the debug | |
27299 | information in such binaries. | |
27300 | ||
27301 | The @samp{zlib} library is likely included with your operating system | |
27302 | distribution; if it is not, you can get the latest version from | |
27303 | @url{http://zlib.net}. | |
27304 | ||
6c7a06a3 TT |
27305 | @item iconv |
27306 | @value{GDBN}'s features related to character sets (@pxref{Character | |
27307 | Sets}) require a functioning @code{iconv} implementation. If you are | |
27308 | on a GNU system, then this is provided by the GNU C Library. Some | |
27309 | other systems also provide a working @code{iconv}. | |
27310 | ||
27311 | On systems with @code{iconv}, you can install GNU Libiconv. If you | |
27312 | have previously installed Libiconv, you can use the | |
27313 | @option{--with-libiconv-prefix} option to configure. | |
27314 | ||
27315 | @value{GDBN}'s top-level @file{configure} and @file{Makefile} will | |
27316 | arrange to build Libiconv if a directory named @file{libiconv} appears | |
27317 | in the top-most source directory. If Libiconv is built this way, and | |
27318 | if the operating system does not provide a suitable @code{iconv} | |
27319 | implementation, then the just-built library will automatically be used | |
27320 | by @value{GDBN}. One easy way to set this up is to download GNU | |
27321 | Libiconv, unpack it, and then rename the directory holding the | |
27322 | Libiconv source code to @samp{libiconv}. | |
7fa2210b DJ |
27323 | @end table |
27324 | ||
27325 | @node Running Configure | |
db2e3e2e | 27326 | @section Invoking the @value{GDBN} @file{configure} Script |
7fa2210b | 27327 | @cindex configuring @value{GDBN} |
db2e3e2e | 27328 | @value{GDBN} comes with a @file{configure} script that automates the process |
8e04817f AC |
27329 | of preparing @value{GDBN} for installation; you can then use @code{make} to |
27330 | build the @code{gdb} program. | |
27331 | @iftex | |
27332 | @c irrelevant in info file; it's as current as the code it lives with. | |
27333 | @footnote{If you have a more recent version of @value{GDBN} than @value{GDBVN}, | |
27334 | look at the @file{README} file in the sources; we may have improved the | |
27335 | installation procedures since publishing this manual.} | |
27336 | @end iftex | |
c4555f82 | 27337 | |
8e04817f AC |
27338 | The @value{GDBN} distribution includes all the source code you need for |
27339 | @value{GDBN} in a single directory, whose name is usually composed by | |
27340 | appending the version number to @samp{gdb}. | |
c4555f82 | 27341 | |
8e04817f AC |
27342 | For example, the @value{GDBN} version @value{GDBVN} distribution is in the |
27343 | @file{gdb-@value{GDBVN}} directory. That directory contains: | |
c4555f82 | 27344 | |
8e04817f AC |
27345 | @table @code |
27346 | @item gdb-@value{GDBVN}/configure @r{(and supporting files)} | |
27347 | script for configuring @value{GDBN} and all its supporting libraries | |
c4555f82 | 27348 | |
8e04817f AC |
27349 | @item gdb-@value{GDBVN}/gdb |
27350 | the source specific to @value{GDBN} itself | |
c4555f82 | 27351 | |
8e04817f AC |
27352 | @item gdb-@value{GDBVN}/bfd |
27353 | source for the Binary File Descriptor library | |
c906108c | 27354 | |
8e04817f AC |
27355 | @item gdb-@value{GDBVN}/include |
27356 | @sc{gnu} include files | |
c906108c | 27357 | |
8e04817f AC |
27358 | @item gdb-@value{GDBVN}/libiberty |
27359 | source for the @samp{-liberty} free software library | |
c906108c | 27360 | |
8e04817f AC |
27361 | @item gdb-@value{GDBVN}/opcodes |
27362 | source for the library of opcode tables and disassemblers | |
c906108c | 27363 | |
8e04817f AC |
27364 | @item gdb-@value{GDBVN}/readline |
27365 | source for the @sc{gnu} command-line interface | |
c906108c | 27366 | |
8e04817f AC |
27367 | @item gdb-@value{GDBVN}/glob |
27368 | source for the @sc{gnu} filename pattern-matching subroutine | |
c906108c | 27369 | |
8e04817f AC |
27370 | @item gdb-@value{GDBVN}/mmalloc |
27371 | source for the @sc{gnu} memory-mapped malloc package | |
27372 | @end table | |
c906108c | 27373 | |
db2e3e2e | 27374 | The simplest way to configure and build @value{GDBN} is to run @file{configure} |
8e04817f AC |
27375 | from the @file{gdb-@var{version-number}} source directory, which in |
27376 | this example is the @file{gdb-@value{GDBVN}} directory. | |
c906108c | 27377 | |
8e04817f | 27378 | First switch to the @file{gdb-@var{version-number}} source directory |
db2e3e2e | 27379 | if you are not already in it; then run @file{configure}. Pass the |
8e04817f AC |
27380 | identifier for the platform on which @value{GDBN} will run as an |
27381 | argument. | |
c906108c | 27382 | |
8e04817f | 27383 | For example: |
c906108c | 27384 | |
474c8240 | 27385 | @smallexample |
8e04817f AC |
27386 | cd gdb-@value{GDBVN} |
27387 | ./configure @var{host} | |
27388 | make | |
474c8240 | 27389 | @end smallexample |
c906108c | 27390 | |
8e04817f AC |
27391 | @noindent |
27392 | where @var{host} is an identifier such as @samp{sun4} or | |
27393 | @samp{decstation}, that identifies the platform where @value{GDBN} will run. | |
db2e3e2e | 27394 | (You can often leave off @var{host}; @file{configure} tries to guess the |
8e04817f | 27395 | correct value by examining your system.) |
c906108c | 27396 | |
8e04817f AC |
27397 | Running @samp{configure @var{host}} and then running @code{make} builds the |
27398 | @file{bfd}, @file{readline}, @file{mmalloc}, and @file{libiberty} | |
27399 | libraries, then @code{gdb} itself. The configured source files, and the | |
27400 | binaries, are left in the corresponding source directories. | |
c906108c | 27401 | |
8e04817f | 27402 | @need 750 |
db2e3e2e | 27403 | @file{configure} is a Bourne-shell (@code{/bin/sh}) script; if your |
8e04817f AC |
27404 | system does not recognize this automatically when you run a different |
27405 | shell, you may need to run @code{sh} on it explicitly: | |
c906108c | 27406 | |
474c8240 | 27407 | @smallexample |
8e04817f | 27408 | sh configure @var{host} |
474c8240 | 27409 | @end smallexample |
c906108c | 27410 | |
db2e3e2e | 27411 | If you run @file{configure} from a directory that contains source |
8e04817f | 27412 | directories for multiple libraries or programs, such as the |
db2e3e2e BW |
27413 | @file{gdb-@value{GDBVN}} source directory for version @value{GDBVN}, |
27414 | @file{configure} | |
8e04817f AC |
27415 | creates configuration files for every directory level underneath (unless |
27416 | you tell it not to, with the @samp{--norecursion} option). | |
27417 | ||
db2e3e2e | 27418 | You should run the @file{configure} script from the top directory in the |
94e91d6d | 27419 | source tree, the @file{gdb-@var{version-number}} directory. If you run |
db2e3e2e | 27420 | @file{configure} from one of the subdirectories, you will configure only |
94e91d6d | 27421 | that subdirectory. That is usually not what you want. In particular, |
db2e3e2e | 27422 | if you run the first @file{configure} from the @file{gdb} subdirectory |
94e91d6d MC |
27423 | of the @file{gdb-@var{version-number}} directory, you will omit the |
27424 | configuration of @file{bfd}, @file{readline}, and other sibling | |
27425 | directories of the @file{gdb} subdirectory. This leads to build errors | |
27426 | about missing include files such as @file{bfd/bfd.h}. | |
c906108c | 27427 | |
8e04817f AC |
27428 | You can install @code{@value{GDBP}} anywhere; it has no hardwired paths. |
27429 | However, you should make sure that the shell on your path (named by | |
27430 | the @samp{SHELL} environment variable) is publicly readable. Remember | |
27431 | that @value{GDBN} uses the shell to start your program---some systems refuse to | |
27432 | let @value{GDBN} debug child processes whose programs are not readable. | |
c906108c | 27433 | |
8e04817f | 27434 | @node Separate Objdir |
79a6e687 | 27435 | @section Compiling @value{GDBN} in Another Directory |
c906108c | 27436 | |
8e04817f AC |
27437 | If you want to run @value{GDBN} versions for several host or target machines, |
27438 | you need a different @code{gdb} compiled for each combination of | |
db2e3e2e | 27439 | host and target. @file{configure} is designed to make this easy by |
8e04817f AC |
27440 | allowing you to generate each configuration in a separate subdirectory, |
27441 | rather than in the source directory. If your @code{make} program | |
27442 | handles the @samp{VPATH} feature (@sc{gnu} @code{make} does), running | |
27443 | @code{make} in each of these directories builds the @code{gdb} | |
27444 | program specified there. | |
c906108c | 27445 | |
db2e3e2e | 27446 | To build @code{gdb} in a separate directory, run @file{configure} |
8e04817f | 27447 | with the @samp{--srcdir} option to specify where to find the source. |
db2e3e2e BW |
27448 | (You also need to specify a path to find @file{configure} |
27449 | itself from your working directory. If the path to @file{configure} | |
8e04817f AC |
27450 | would be the same as the argument to @samp{--srcdir}, you can leave out |
27451 | the @samp{--srcdir} option; it is assumed.) | |
c906108c | 27452 | |
8e04817f AC |
27453 | For example, with version @value{GDBVN}, you can build @value{GDBN} in a |
27454 | separate directory for a Sun 4 like this: | |
c906108c | 27455 | |
474c8240 | 27456 | @smallexample |
8e04817f AC |
27457 | @group |
27458 | cd gdb-@value{GDBVN} | |
27459 | mkdir ../gdb-sun4 | |
27460 | cd ../gdb-sun4 | |
27461 | ../gdb-@value{GDBVN}/configure sun4 | |
27462 | make | |
27463 | @end group | |
474c8240 | 27464 | @end smallexample |
c906108c | 27465 | |
db2e3e2e | 27466 | When @file{configure} builds a configuration using a remote source |
8e04817f AC |
27467 | directory, it creates a tree for the binaries with the same structure |
27468 | (and using the same names) as the tree under the source directory. In | |
27469 | the example, you'd find the Sun 4 library @file{libiberty.a} in the | |
27470 | directory @file{gdb-sun4/libiberty}, and @value{GDBN} itself in | |
27471 | @file{gdb-sun4/gdb}. | |
c906108c | 27472 | |
94e91d6d MC |
27473 | Make sure that your path to the @file{configure} script has just one |
27474 | instance of @file{gdb} in it. If your path to @file{configure} looks | |
27475 | like @file{../gdb-@value{GDBVN}/gdb/configure}, you are configuring only | |
27476 | one subdirectory of @value{GDBN}, not the whole package. This leads to | |
27477 | build errors about missing include files such as @file{bfd/bfd.h}. | |
27478 | ||
8e04817f AC |
27479 | One popular reason to build several @value{GDBN} configurations in separate |
27480 | directories is to configure @value{GDBN} for cross-compiling (where | |
27481 | @value{GDBN} runs on one machine---the @dfn{host}---while debugging | |
27482 | programs that run on another machine---the @dfn{target}). | |
27483 | You specify a cross-debugging target by | |
db2e3e2e | 27484 | giving the @samp{--target=@var{target}} option to @file{configure}. |
c906108c | 27485 | |
8e04817f AC |
27486 | When you run @code{make} to build a program or library, you must run |
27487 | it in a configured directory---whatever directory you were in when you | |
db2e3e2e | 27488 | called @file{configure} (or one of its subdirectories). |
c906108c | 27489 | |
db2e3e2e | 27490 | The @code{Makefile} that @file{configure} generates in each source |
8e04817f AC |
27491 | directory also runs recursively. If you type @code{make} in a source |
27492 | directory such as @file{gdb-@value{GDBVN}} (or in a separate configured | |
27493 | directory configured with @samp{--srcdir=@var{dirname}/gdb-@value{GDBVN}}), you | |
27494 | will build all the required libraries, and then build GDB. | |
c906108c | 27495 | |
8e04817f AC |
27496 | When you have multiple hosts or targets configured in separate |
27497 | directories, you can run @code{make} on them in parallel (for example, | |
27498 | if they are NFS-mounted on each of the hosts); they will not interfere | |
27499 | with each other. | |
c906108c | 27500 | |
8e04817f | 27501 | @node Config Names |
79a6e687 | 27502 | @section Specifying Names for Hosts and Targets |
c906108c | 27503 | |
db2e3e2e | 27504 | The specifications used for hosts and targets in the @file{configure} |
8e04817f AC |
27505 | script are based on a three-part naming scheme, but some short predefined |
27506 | aliases are also supported. The full naming scheme encodes three pieces | |
27507 | of information in the following pattern: | |
c906108c | 27508 | |
474c8240 | 27509 | @smallexample |
8e04817f | 27510 | @var{architecture}-@var{vendor}-@var{os} |
474c8240 | 27511 | @end smallexample |
c906108c | 27512 | |
8e04817f AC |
27513 | For example, you can use the alias @code{sun4} as a @var{host} argument, |
27514 | or as the value for @var{target} in a @code{--target=@var{target}} | |
27515 | option. The equivalent full name is @samp{sparc-sun-sunos4}. | |
c906108c | 27516 | |
db2e3e2e | 27517 | The @file{configure} script accompanying @value{GDBN} does not provide |
8e04817f | 27518 | any query facility to list all supported host and target names or |
db2e3e2e | 27519 | aliases. @file{configure} calls the Bourne shell script |
8e04817f AC |
27520 | @code{config.sub} to map abbreviations to full names; you can read the |
27521 | script, if you wish, or you can use it to test your guesses on | |
27522 | abbreviations---for example: | |
c906108c | 27523 | |
8e04817f AC |
27524 | @smallexample |
27525 | % sh config.sub i386-linux | |
27526 | i386-pc-linux-gnu | |
27527 | % sh config.sub alpha-linux | |
27528 | alpha-unknown-linux-gnu | |
27529 | % sh config.sub hp9k700 | |
27530 | hppa1.1-hp-hpux | |
27531 | % sh config.sub sun4 | |
27532 | sparc-sun-sunos4.1.1 | |
27533 | % sh config.sub sun3 | |
27534 | m68k-sun-sunos4.1.1 | |
27535 | % sh config.sub i986v | |
27536 | Invalid configuration `i986v': machine `i986v' not recognized | |
27537 | @end smallexample | |
c906108c | 27538 | |
8e04817f AC |
27539 | @noindent |
27540 | @code{config.sub} is also distributed in the @value{GDBN} source | |
27541 | directory (@file{gdb-@value{GDBVN}}, for version @value{GDBVN}). | |
d700128c | 27542 | |
8e04817f | 27543 | @node Configure Options |
db2e3e2e | 27544 | @section @file{configure} Options |
c906108c | 27545 | |
db2e3e2e BW |
27546 | Here is a summary of the @file{configure} options and arguments that |
27547 | are most often useful for building @value{GDBN}. @file{configure} also has | |
8e04817f | 27548 | several other options not listed here. @inforef{What Configure |
db2e3e2e | 27549 | Does,,configure.info}, for a full explanation of @file{configure}. |
c906108c | 27550 | |
474c8240 | 27551 | @smallexample |
8e04817f AC |
27552 | configure @r{[}--help@r{]} |
27553 | @r{[}--prefix=@var{dir}@r{]} | |
27554 | @r{[}--exec-prefix=@var{dir}@r{]} | |
27555 | @r{[}--srcdir=@var{dirname}@r{]} | |
27556 | @r{[}--norecursion@r{]} @r{[}--rm@r{]} | |
27557 | @r{[}--target=@var{target}@r{]} | |
27558 | @var{host} | |
474c8240 | 27559 | @end smallexample |
c906108c | 27560 | |
8e04817f AC |
27561 | @noindent |
27562 | You may introduce options with a single @samp{-} rather than | |
27563 | @samp{--} if you prefer; but you may abbreviate option names if you use | |
27564 | @samp{--}. | |
c906108c | 27565 | |
8e04817f AC |
27566 | @table @code |
27567 | @item --help | |
db2e3e2e | 27568 | Display a quick summary of how to invoke @file{configure}. |
c906108c | 27569 | |
8e04817f AC |
27570 | @item --prefix=@var{dir} |
27571 | Configure the source to install programs and files under directory | |
27572 | @file{@var{dir}}. | |
c906108c | 27573 | |
8e04817f AC |
27574 | @item --exec-prefix=@var{dir} |
27575 | Configure the source to install programs under directory | |
27576 | @file{@var{dir}}. | |
c906108c | 27577 | |
8e04817f AC |
27578 | @c avoid splitting the warning from the explanation: |
27579 | @need 2000 | |
27580 | @item --srcdir=@var{dirname} | |
27581 | @strong{Warning: using this option requires @sc{gnu} @code{make}, or another | |
27582 | @code{make} that implements the @code{VPATH} feature.}@* | |
27583 | Use this option to make configurations in directories separate from the | |
27584 | @value{GDBN} source directories. Among other things, you can use this to | |
27585 | build (or maintain) several configurations simultaneously, in separate | |
db2e3e2e | 27586 | directories. @file{configure} writes configuration-specific files in |
8e04817f | 27587 | the current directory, but arranges for them to use the source in the |
db2e3e2e | 27588 | directory @var{dirname}. @file{configure} creates directories under |
8e04817f AC |
27589 | the working directory in parallel to the source directories below |
27590 | @var{dirname}. | |
c906108c | 27591 | |
8e04817f | 27592 | @item --norecursion |
db2e3e2e | 27593 | Configure only the directory level where @file{configure} is executed; do not |
8e04817f | 27594 | propagate configuration to subdirectories. |
c906108c | 27595 | |
8e04817f AC |
27596 | @item --target=@var{target} |
27597 | Configure @value{GDBN} for cross-debugging programs running on the specified | |
27598 | @var{target}. Without this option, @value{GDBN} is configured to debug | |
27599 | programs that run on the same machine (@var{host}) as @value{GDBN} itself. | |
c906108c | 27600 | |
8e04817f | 27601 | There is no convenient way to generate a list of all available targets. |
c906108c | 27602 | |
8e04817f AC |
27603 | @item @var{host} @dots{} |
27604 | Configure @value{GDBN} to run on the specified @var{host}. | |
c906108c | 27605 | |
8e04817f AC |
27606 | There is no convenient way to generate a list of all available hosts. |
27607 | @end table | |
c906108c | 27608 | |
8e04817f AC |
27609 | There are many other options available as well, but they are generally |
27610 | needed for special purposes only. | |
c906108c | 27611 | |
098b41a6 JG |
27612 | @node System-wide configuration |
27613 | @section System-wide configuration and settings | |
27614 | @cindex system-wide init file | |
27615 | ||
27616 | @value{GDBN} can be configured to have a system-wide init file; | |
27617 | this file will be read and executed at startup (@pxref{Startup, , What | |
27618 | @value{GDBN} does during startup}). | |
27619 | ||
27620 | Here is the corresponding configure option: | |
27621 | ||
27622 | @table @code | |
27623 | @item --with-system-gdbinit=@var{file} | |
27624 | Specify that the default location of the system-wide init file is | |
27625 | @var{file}. | |
27626 | @end table | |
27627 | ||
27628 | If @value{GDBN} has been configured with the option @option{--prefix=$prefix}, | |
27629 | it may be subject to relocation. Two possible cases: | |
27630 | ||
27631 | @itemize @bullet | |
27632 | @item | |
27633 | If the default location of this init file contains @file{$prefix}, | |
27634 | it will be subject to relocation. Suppose that the configure options | |
27635 | are @option{--prefix=$prefix --with-system-gdbinit=$prefix/etc/gdbinit}; | |
27636 | if @value{GDBN} is moved from @file{$prefix} to @file{$install}, the system | |
27637 | init file is looked for as @file{$install/etc/gdbinit} instead of | |
27638 | @file{$prefix/etc/gdbinit}. | |
27639 | ||
27640 | @item | |
27641 | By contrast, if the default location does not contain the prefix, | |
27642 | it will not be relocated. E.g.@: if @value{GDBN} has been configured with | |
27643 | @option{--prefix=/usr/local --with-system-gdbinit=/usr/share/gdb/gdbinit}, | |
27644 | then @value{GDBN} will always look for @file{/usr/share/gdb/gdbinit}, | |
27645 | wherever @value{GDBN} is installed. | |
27646 | @end itemize | |
27647 | ||
8e04817f AC |
27648 | @node Maintenance Commands |
27649 | @appendix Maintenance Commands | |
27650 | @cindex maintenance commands | |
27651 | @cindex internal commands | |
c906108c | 27652 | |
8e04817f | 27653 | In addition to commands intended for @value{GDBN} users, @value{GDBN} |
09d4efe1 EZ |
27654 | includes a number of commands intended for @value{GDBN} developers, |
27655 | that are not documented elsewhere in this manual. These commands are | |
da316a69 EZ |
27656 | provided here for reference. (For commands that turn on debugging |
27657 | messages, see @ref{Debugging Output}.) | |
c906108c | 27658 | |
8e04817f | 27659 | @table @code |
09d4efe1 | 27660 | @kindex maint agent |
782b2b07 | 27661 | @kindex maint agent-eval |
09d4efe1 | 27662 | @item maint agent @var{expression} |
782b2b07 | 27663 | @itemx maint agent-eval @var{expression} |
09d4efe1 EZ |
27664 | Translate the given @var{expression} into remote agent bytecodes. |
27665 | This command is useful for debugging the Agent Expression mechanism | |
782b2b07 SS |
27666 | (@pxref{Agent Expressions}). The @samp{agent} version produces an |
27667 | expression useful for data collection, such as by tracepoints, while | |
27668 | @samp{maint agent-eval} produces an expression that evaluates directly | |
27669 | to a result. For instance, a collection expression for @code{globa + | |
27670 | globb} will include bytecodes to record four bytes of memory at each | |
27671 | of the addresses of @code{globa} and @code{globb}, while discarding | |
27672 | the result of the addition, while an evaluation expression will do the | |
27673 | addition and return the sum. | |
09d4efe1 | 27674 | |
8e04817f AC |
27675 | @kindex maint info breakpoints |
27676 | @item @anchor{maint info breakpoints}maint info breakpoints | |
27677 | Using the same format as @samp{info breakpoints}, display both the | |
27678 | breakpoints you've set explicitly, and those @value{GDBN} is using for | |
27679 | internal purposes. Internal breakpoints are shown with negative | |
27680 | breakpoint numbers. The type column identifies what kind of breakpoint | |
27681 | is shown: | |
c906108c | 27682 | |
8e04817f AC |
27683 | @table @code |
27684 | @item breakpoint | |
27685 | Normal, explicitly set breakpoint. | |
c906108c | 27686 | |
8e04817f AC |
27687 | @item watchpoint |
27688 | Normal, explicitly set watchpoint. | |
c906108c | 27689 | |
8e04817f AC |
27690 | @item longjmp |
27691 | Internal breakpoint, used to handle correctly stepping through | |
27692 | @code{longjmp} calls. | |
c906108c | 27693 | |
8e04817f AC |
27694 | @item longjmp resume |
27695 | Internal breakpoint at the target of a @code{longjmp}. | |
c906108c | 27696 | |
8e04817f AC |
27697 | @item until |
27698 | Temporary internal breakpoint used by the @value{GDBN} @code{until} command. | |
c906108c | 27699 | |
8e04817f AC |
27700 | @item finish |
27701 | Temporary internal breakpoint used by the @value{GDBN} @code{finish} command. | |
c906108c | 27702 | |
8e04817f AC |
27703 | @item shlib events |
27704 | Shared library events. | |
c906108c | 27705 | |
8e04817f | 27706 | @end table |
c906108c | 27707 | |
fff08868 HZ |
27708 | @kindex set displaced-stepping |
27709 | @kindex show displaced-stepping | |
237fc4c9 PA |
27710 | @cindex displaced stepping support |
27711 | @cindex out-of-line single-stepping | |
fff08868 HZ |
27712 | @item set displaced-stepping |
27713 | @itemx show displaced-stepping | |
237fc4c9 | 27714 | Control whether or not @value{GDBN} will do @dfn{displaced stepping} |
fff08868 HZ |
27715 | if the target supports it. Displaced stepping is a way to single-step |
27716 | over breakpoints without removing them from the inferior, by executing | |
27717 | an out-of-line copy of the instruction that was originally at the | |
27718 | breakpoint location. It is also known as out-of-line single-stepping. | |
27719 | ||
27720 | @table @code | |
27721 | @item set displaced-stepping on | |
27722 | If the target architecture supports it, @value{GDBN} will use | |
27723 | displaced stepping to step over breakpoints. | |
27724 | ||
27725 | @item set displaced-stepping off | |
27726 | @value{GDBN} will not use displaced stepping to step over breakpoints, | |
27727 | even if such is supported by the target architecture. | |
27728 | ||
27729 | @cindex non-stop mode, and @samp{set displaced-stepping} | |
27730 | @item set displaced-stepping auto | |
27731 | This is the default mode. @value{GDBN} will use displaced stepping | |
27732 | only if non-stop mode is active (@pxref{Non-Stop Mode}) and the target | |
27733 | architecture supports displaced stepping. | |
27734 | @end table | |
237fc4c9 | 27735 | |
09d4efe1 EZ |
27736 | @kindex maint check-symtabs |
27737 | @item maint check-symtabs | |
27738 | Check the consistency of psymtabs and symtabs. | |
27739 | ||
27740 | @kindex maint cplus first_component | |
27741 | @item maint cplus first_component @var{name} | |
27742 | Print the first C@t{++} class/namespace component of @var{name}. | |
27743 | ||
27744 | @kindex maint cplus namespace | |
27745 | @item maint cplus namespace | |
27746 | Print the list of possible C@t{++} namespaces. | |
27747 | ||
27748 | @kindex maint demangle | |
27749 | @item maint demangle @var{name} | |
d3e8051b | 27750 | Demangle a C@t{++} or Objective-C mangled @var{name}. |
09d4efe1 EZ |
27751 | |
27752 | @kindex maint deprecate | |
27753 | @kindex maint undeprecate | |
27754 | @cindex deprecated commands | |
27755 | @item maint deprecate @var{command} @r{[}@var{replacement}@r{]} | |
27756 | @itemx maint undeprecate @var{command} | |
27757 | Deprecate or undeprecate the named @var{command}. Deprecated commands | |
27758 | cause @value{GDBN} to issue a warning when you use them. The optional | |
27759 | argument @var{replacement} says which newer command should be used in | |
27760 | favor of the deprecated one; if it is given, @value{GDBN} will mention | |
27761 | the replacement as part of the warning. | |
27762 | ||
27763 | @kindex maint dump-me | |
27764 | @item maint dump-me | |
721c2651 | 27765 | @cindex @code{SIGQUIT} signal, dump core of @value{GDBN} |
09d4efe1 | 27766 | Cause a fatal signal in the debugger and force it to dump its core. |
721c2651 EZ |
27767 | This is supported only on systems which support aborting a program |
27768 | with the @code{SIGQUIT} signal. | |
09d4efe1 | 27769 | |
8d30a00d AC |
27770 | @kindex maint internal-error |
27771 | @kindex maint internal-warning | |
09d4efe1 EZ |
27772 | @item maint internal-error @r{[}@var{message-text}@r{]} |
27773 | @itemx maint internal-warning @r{[}@var{message-text}@r{]} | |
8d30a00d AC |
27774 | Cause @value{GDBN} to call the internal function @code{internal_error} |
27775 | or @code{internal_warning} and hence behave as though an internal error | |
27776 | or internal warning has been detected. In addition to reporting the | |
27777 | internal problem, these functions give the user the opportunity to | |
27778 | either quit @value{GDBN} or create a core file of the current | |
27779 | @value{GDBN} session. | |
27780 | ||
09d4efe1 EZ |
27781 | These commands take an optional parameter @var{message-text} that is |
27782 | used as the text of the error or warning message. | |
27783 | ||
d3e8051b | 27784 | Here's an example of using @code{internal-error}: |
09d4efe1 | 27785 | |
8d30a00d | 27786 | @smallexample |
f7dc1244 | 27787 | (@value{GDBP}) @kbd{maint internal-error testing, 1, 2} |
8d30a00d AC |
27788 | @dots{}/maint.c:121: internal-error: testing, 1, 2 |
27789 | A problem internal to GDB has been detected. Further | |
27790 | debugging may prove unreliable. | |
27791 | Quit this debugging session? (y or n) @kbd{n} | |
27792 | Create a core file? (y or n) @kbd{n} | |
f7dc1244 | 27793 | (@value{GDBP}) |
8d30a00d AC |
27794 | @end smallexample |
27795 | ||
3c16cced PA |
27796 | @cindex @value{GDBN} internal error |
27797 | @cindex internal errors, control of @value{GDBN} behavior | |
27798 | ||
27799 | @kindex maint set internal-error | |
27800 | @kindex maint show internal-error | |
27801 | @kindex maint set internal-warning | |
27802 | @kindex maint show internal-warning | |
27803 | @item maint set internal-error @var{action} [ask|yes|no] | |
27804 | @itemx maint show internal-error @var{action} | |
27805 | @itemx maint set internal-warning @var{action} [ask|yes|no] | |
27806 | @itemx maint show internal-warning @var{action} | |
27807 | When @value{GDBN} reports an internal problem (error or warning) it | |
27808 | gives the user the opportunity to both quit @value{GDBN} and create a | |
27809 | core file of the current @value{GDBN} session. These commands let you | |
27810 | override the default behaviour for each particular @var{action}, | |
27811 | described in the table below. | |
27812 | ||
27813 | @table @samp | |
27814 | @item quit | |
27815 | You can specify that @value{GDBN} should always (yes) or never (no) | |
27816 | quit. The default is to ask the user what to do. | |
27817 | ||
27818 | @item corefile | |
27819 | You can specify that @value{GDBN} should always (yes) or never (no) | |
27820 | create a core file. The default is to ask the user what to do. | |
27821 | @end table | |
27822 | ||
09d4efe1 EZ |
27823 | @kindex maint packet |
27824 | @item maint packet @var{text} | |
27825 | If @value{GDBN} is talking to an inferior via the serial protocol, | |
27826 | then this command sends the string @var{text} to the inferior, and | |
27827 | displays the response packet. @value{GDBN} supplies the initial | |
27828 | @samp{$} character, the terminating @samp{#} character, and the | |
27829 | checksum. | |
27830 | ||
27831 | @kindex maint print architecture | |
27832 | @item maint print architecture @r{[}@var{file}@r{]} | |
27833 | Print the entire architecture configuration. The optional argument | |
27834 | @var{file} names the file where the output goes. | |
8d30a00d | 27835 | |
81adfced DJ |
27836 | @kindex maint print c-tdesc |
27837 | @item maint print c-tdesc | |
27838 | Print the current target description (@pxref{Target Descriptions}) as | |
27839 | a C source file. The created source file can be used in @value{GDBN} | |
27840 | when an XML parser is not available to parse the description. | |
27841 | ||
00905d52 AC |
27842 | @kindex maint print dummy-frames |
27843 | @item maint print dummy-frames | |
00905d52 AC |
27844 | Prints the contents of @value{GDBN}'s internal dummy-frame stack. |
27845 | ||
27846 | @smallexample | |
f7dc1244 | 27847 | (@value{GDBP}) @kbd{b add} |
00905d52 | 27848 | @dots{} |
f7dc1244 | 27849 | (@value{GDBP}) @kbd{print add(2,3)} |
00905d52 AC |
27850 | Breakpoint 2, add (a=2, b=3) at @dots{} |
27851 | 58 return (a + b); | |
27852 | The program being debugged stopped while in a function called from GDB. | |
27853 | @dots{} | |
f7dc1244 | 27854 | (@value{GDBP}) @kbd{maint print dummy-frames} |
00905d52 AC |
27855 | 0x1a57c80: pc=0x01014068 fp=0x0200bddc sp=0x0200bdd6 |
27856 | top=0x0200bdd4 id=@{stack=0x200bddc,code=0x101405c@} | |
27857 | call_lo=0x01014000 call_hi=0x01014001 | |
f7dc1244 | 27858 | (@value{GDBP}) |
00905d52 AC |
27859 | @end smallexample |
27860 | ||
27861 | Takes an optional file parameter. | |
27862 | ||
0680b120 AC |
27863 | @kindex maint print registers |
27864 | @kindex maint print raw-registers | |
27865 | @kindex maint print cooked-registers | |
617073a9 | 27866 | @kindex maint print register-groups |
09d4efe1 EZ |
27867 | @item maint print registers @r{[}@var{file}@r{]} |
27868 | @itemx maint print raw-registers @r{[}@var{file}@r{]} | |
27869 | @itemx maint print cooked-registers @r{[}@var{file}@r{]} | |
27870 | @itemx maint print register-groups @r{[}@var{file}@r{]} | |
0680b120 AC |
27871 | Print @value{GDBN}'s internal register data structures. |
27872 | ||
617073a9 AC |
27873 | The command @code{maint print raw-registers} includes the contents of |
27874 | the raw register cache; the command @code{maint print cooked-registers} | |
27875 | includes the (cooked) value of all registers; and the command | |
27876 | @code{maint print register-groups} includes the groups that each | |
27877 | register is a member of. @xref{Registers,, Registers, gdbint, | |
27878 | @value{GDBN} Internals}. | |
0680b120 | 27879 | |
09d4efe1 EZ |
27880 | These commands take an optional parameter, a file name to which to |
27881 | write the information. | |
0680b120 | 27882 | |
617073a9 | 27883 | @kindex maint print reggroups |
09d4efe1 EZ |
27884 | @item maint print reggroups @r{[}@var{file}@r{]} |
27885 | Print @value{GDBN}'s internal register group data structures. The | |
27886 | optional argument @var{file} tells to what file to write the | |
27887 | information. | |
617073a9 | 27888 | |
09d4efe1 | 27889 | The register groups info looks like this: |
617073a9 AC |
27890 | |
27891 | @smallexample | |
f7dc1244 | 27892 | (@value{GDBP}) @kbd{maint print reggroups} |
b383017d RM |
27893 | Group Type |
27894 | general user | |
27895 | float user | |
27896 | all user | |
27897 | vector user | |
27898 | system user | |
27899 | save internal | |
27900 | restore internal | |
617073a9 AC |
27901 | @end smallexample |
27902 | ||
09d4efe1 EZ |
27903 | @kindex flushregs |
27904 | @item flushregs | |
27905 | This command forces @value{GDBN} to flush its internal register cache. | |
27906 | ||
27907 | @kindex maint print objfiles | |
27908 | @cindex info for known object files | |
27909 | @item maint print objfiles | |
27910 | Print a dump of all known object files. For each object file, this | |
27911 | command prints its name, address in memory, and all of its psymtabs | |
27912 | and symtabs. | |
27913 | ||
27914 | @kindex maint print statistics | |
27915 | @cindex bcache statistics | |
27916 | @item maint print statistics | |
27917 | This command prints, for each object file in the program, various data | |
27918 | about that object file followed by the byte cache (@dfn{bcache}) | |
27919 | statistics for the object file. The objfile data includes the number | |
d3e8051b | 27920 | of minimal, partial, full, and stabs symbols, the number of types |
09d4efe1 EZ |
27921 | defined by the objfile, the number of as yet unexpanded psym tables, |
27922 | the number of line tables and string tables, and the amount of memory | |
27923 | used by the various tables. The bcache statistics include the counts, | |
27924 | sizes, and counts of duplicates of all and unique objects, max, | |
27925 | average, and median entry size, total memory used and its overhead and | |
27926 | savings, and various measures of the hash table size and chain | |
27927 | lengths. | |
27928 | ||
c7ba131e JB |
27929 | @kindex maint print target-stack |
27930 | @cindex target stack description | |
27931 | @item maint print target-stack | |
27932 | A @dfn{target} is an interface between the debugger and a particular | |
27933 | kind of file or process. Targets can be stacked in @dfn{strata}, | |
27934 | so that more than one target can potentially respond to a request. | |
27935 | In particular, memory accesses will walk down the stack of targets | |
27936 | until they find a target that is interested in handling that particular | |
27937 | address. | |
27938 | ||
27939 | This command prints a short description of each layer that was pushed on | |
27940 | the @dfn{target stack}, starting from the top layer down to the bottom one. | |
27941 | ||
09d4efe1 EZ |
27942 | @kindex maint print type |
27943 | @cindex type chain of a data type | |
27944 | @item maint print type @var{expr} | |
27945 | Print the type chain for a type specified by @var{expr}. The argument | |
27946 | can be either a type name or a symbol. If it is a symbol, the type of | |
27947 | that symbol is described. The type chain produced by this command is | |
27948 | a recursive definition of the data type as stored in @value{GDBN}'s | |
27949 | data structures, including its flags and contained types. | |
27950 | ||
27951 | @kindex maint set dwarf2 max-cache-age | |
27952 | @kindex maint show dwarf2 max-cache-age | |
27953 | @item maint set dwarf2 max-cache-age | |
27954 | @itemx maint show dwarf2 max-cache-age | |
27955 | Control the DWARF 2 compilation unit cache. | |
27956 | ||
27957 | @cindex DWARF 2 compilation units cache | |
27958 | In object files with inter-compilation-unit references, such as those | |
27959 | produced by the GCC option @samp{-feliminate-dwarf2-dups}, the DWARF 2 | |
27960 | reader needs to frequently refer to previously read compilation units. | |
27961 | This setting controls how long a compilation unit will remain in the | |
27962 | cache if it is not referenced. A higher limit means that cached | |
27963 | compilation units will be stored in memory longer, and more total | |
27964 | memory will be used. Setting it to zero disables caching, which will | |
27965 | slow down @value{GDBN} startup, but reduce memory consumption. | |
27966 | ||
e7ba9c65 DJ |
27967 | @kindex maint set profile |
27968 | @kindex maint show profile | |
27969 | @cindex profiling GDB | |
27970 | @item maint set profile | |
27971 | @itemx maint show profile | |
27972 | Control profiling of @value{GDBN}. | |
27973 | ||
27974 | Profiling will be disabled until you use the @samp{maint set profile} | |
27975 | command to enable it. When you enable profiling, the system will begin | |
27976 | collecting timing and execution count data; when you disable profiling or | |
27977 | exit @value{GDBN}, the results will be written to a log file. Remember that | |
27978 | if you use profiling, @value{GDBN} will overwrite the profiling log file | |
27979 | (often called @file{gmon.out}). If you have a record of important profiling | |
27980 | data in a @file{gmon.out} file, be sure to move it to a safe location. | |
27981 | ||
27982 | Configuring with @samp{--enable-profiling} arranges for @value{GDBN} to be | |
b383017d | 27983 | compiled with the @samp{-pg} compiler option. |
e7ba9c65 | 27984 | |
cbe54154 PA |
27985 | @kindex maint set show-debug-regs |
27986 | @kindex maint show show-debug-regs | |
eac35c4e | 27987 | @cindex hardware debug registers |
cbe54154 PA |
27988 | @item maint set show-debug-regs |
27989 | @itemx maint show show-debug-regs | |
eac35c4e | 27990 | Control whether to show variables that mirror the hardware debug |
09d4efe1 | 27991 | registers. Use @code{ON} to enable, @code{OFF} to disable. If |
3f94c067 | 27992 | enabled, the debug registers values are shown when @value{GDBN} inserts or |
09d4efe1 EZ |
27993 | removes a hardware breakpoint or watchpoint, and when the inferior |
27994 | triggers a hardware-assisted breakpoint or watchpoint. | |
27995 | ||
27996 | @kindex maint space | |
27997 | @cindex memory used by commands | |
27998 | @item maint space | |
27999 | Control whether to display memory usage for each command. If set to a | |
28000 | nonzero value, @value{GDBN} will display how much memory each command | |
28001 | took, following the command's own output. This can also be requested | |
28002 | by invoking @value{GDBN} with the @option{--statistics} command-line | |
28003 | switch (@pxref{Mode Options}). | |
28004 | ||
28005 | @kindex maint time | |
28006 | @cindex time of command execution | |
28007 | @item maint time | |
28008 | Control whether to display the execution time for each command. If | |
28009 | set to a nonzero value, @value{GDBN} will display how much time it | |
28010 | took to execute each command, following the command's own output. | |
e2b7ddea VP |
28011 | The time is not printed for the commands that run the target, since |
28012 | there's no mechanism currently to compute how much time was spend | |
28013 | by @value{GDBN} and how much time was spend by the program been debugged. | |
28014 | it's not possibly currently | |
09d4efe1 EZ |
28015 | This can also be requested by invoking @value{GDBN} with the |
28016 | @option{--statistics} command-line switch (@pxref{Mode Options}). | |
28017 | ||
28018 | @kindex maint translate-address | |
28019 | @item maint translate-address @r{[}@var{section}@r{]} @var{addr} | |
28020 | Find the symbol stored at the location specified by the address | |
28021 | @var{addr} and an optional section name @var{section}. If found, | |
28022 | @value{GDBN} prints the name of the closest symbol and an offset from | |
28023 | the symbol's location to the specified address. This is similar to | |
28024 | the @code{info address} command (@pxref{Symbols}), except that this | |
28025 | command also allows to find symbols in other sections. | |
ae038cb0 | 28026 | |
c14c28ba PP |
28027 | If section was not specified, the section in which the symbol was found |
28028 | is also printed. For dynamically linked executables, the name of | |
28029 | executable or shared library containing the symbol is printed as well. | |
28030 | ||
8e04817f | 28031 | @end table |
c906108c | 28032 | |
9c16f35a EZ |
28033 | The following command is useful for non-interactive invocations of |
28034 | @value{GDBN}, such as in the test suite. | |
28035 | ||
28036 | @table @code | |
28037 | @item set watchdog @var{nsec} | |
28038 | @kindex set watchdog | |
28039 | @cindex watchdog timer | |
28040 | @cindex timeout for commands | |
28041 | Set the maximum number of seconds @value{GDBN} will wait for the | |
28042 | target operation to finish. If this time expires, @value{GDBN} | |
28043 | reports and error and the command is aborted. | |
28044 | ||
28045 | @item show watchdog | |
28046 | Show the current setting of the target wait timeout. | |
28047 | @end table | |
c906108c | 28048 | |
e0ce93ac | 28049 | @node Remote Protocol |
8e04817f | 28050 | @appendix @value{GDBN} Remote Serial Protocol |
c906108c | 28051 | |
ee2d5c50 AC |
28052 | @menu |
28053 | * Overview:: | |
28054 | * Packets:: | |
28055 | * Stop Reply Packets:: | |
28056 | * General Query Packets:: | |
28057 | * Register Packet Format:: | |
9d29849a | 28058 | * Tracepoint Packets:: |
a6b151f1 | 28059 | * Host I/O Packets:: |
9a6253be | 28060 | * Interrupts:: |
8b23ecc4 SL |
28061 | * Notification Packets:: |
28062 | * Remote Non-Stop:: | |
a6f3e723 | 28063 | * Packet Acknowledgment:: |
ee2d5c50 | 28064 | * Examples:: |
79a6e687 | 28065 | * File-I/O Remote Protocol Extension:: |
cfa9d6d9 | 28066 | * Library List Format:: |
79a6e687 | 28067 | * Memory Map Format:: |
ee2d5c50 AC |
28068 | @end menu |
28069 | ||
28070 | @node Overview | |
28071 | @section Overview | |
28072 | ||
8e04817f AC |
28073 | There may be occasions when you need to know something about the |
28074 | protocol---for example, if there is only one serial port to your target | |
28075 | machine, you might want your program to do something special if it | |
28076 | recognizes a packet meant for @value{GDBN}. | |
c906108c | 28077 | |
d2c6833e | 28078 | In the examples below, @samp{->} and @samp{<-} are used to indicate |
bf06d120 | 28079 | transmitted and received data, respectively. |
c906108c | 28080 | |
8e04817f AC |
28081 | @cindex protocol, @value{GDBN} remote serial |
28082 | @cindex serial protocol, @value{GDBN} remote | |
28083 | @cindex remote serial protocol | |
8b23ecc4 SL |
28084 | All @value{GDBN} commands and responses (other than acknowledgments |
28085 | and notifications, see @ref{Notification Packets}) are sent as a | |
28086 | @var{packet}. A @var{packet} is introduced with the character | |
8e04817f AC |
28087 | @samp{$}, the actual @var{packet-data}, and the terminating character |
28088 | @samp{#} followed by a two-digit @var{checksum}: | |
c906108c | 28089 | |
474c8240 | 28090 | @smallexample |
8e04817f | 28091 | @code{$}@var{packet-data}@code{#}@var{checksum} |
474c8240 | 28092 | @end smallexample |
8e04817f | 28093 | @noindent |
c906108c | 28094 | |
8e04817f AC |
28095 | @cindex checksum, for @value{GDBN} remote |
28096 | @noindent | |
28097 | The two-digit @var{checksum} is computed as the modulo 256 sum of all | |
28098 | characters between the leading @samp{$} and the trailing @samp{#} (an | |
28099 | eight bit unsigned checksum). | |
c906108c | 28100 | |
8e04817f AC |
28101 | Implementors should note that prior to @value{GDBN} 5.0 the protocol |
28102 | specification also included an optional two-digit @var{sequence-id}: | |
c906108c | 28103 | |
474c8240 | 28104 | @smallexample |
8e04817f | 28105 | @code{$}@var{sequence-id}@code{:}@var{packet-data}@code{#}@var{checksum} |
474c8240 | 28106 | @end smallexample |
c906108c | 28107 | |
8e04817f AC |
28108 | @cindex sequence-id, for @value{GDBN} remote |
28109 | @noindent | |
28110 | That @var{sequence-id} was appended to the acknowledgment. @value{GDBN} | |
28111 | has never output @var{sequence-id}s. Stubs that handle packets added | |
28112 | since @value{GDBN} 5.0 must not accept @var{sequence-id}. | |
c906108c | 28113 | |
8e04817f AC |
28114 | When either the host or the target machine receives a packet, the first |
28115 | response expected is an acknowledgment: either @samp{+} (to indicate | |
28116 | the package was received correctly) or @samp{-} (to request | |
28117 | retransmission): | |
c906108c | 28118 | |
474c8240 | 28119 | @smallexample |
d2c6833e AC |
28120 | -> @code{$}@var{packet-data}@code{#}@var{checksum} |
28121 | <- @code{+} | |
474c8240 | 28122 | @end smallexample |
8e04817f | 28123 | @noindent |
53a5351d | 28124 | |
a6f3e723 SL |
28125 | The @samp{+}/@samp{-} acknowledgments can be disabled |
28126 | once a connection is established. | |
28127 | @xref{Packet Acknowledgment}, for details. | |
28128 | ||
8e04817f AC |
28129 | The host (@value{GDBN}) sends @var{command}s, and the target (the |
28130 | debugging stub incorporated in your program) sends a @var{response}. In | |
28131 | the case of step and continue @var{command}s, the response is only sent | |
8b23ecc4 SL |
28132 | when the operation has completed, and the target has again stopped all |
28133 | threads in all attached processes. This is the default all-stop mode | |
28134 | behavior, but the remote protocol also supports @value{GDBN}'s non-stop | |
28135 | execution mode; see @ref{Remote Non-Stop}, for details. | |
c906108c | 28136 | |
8e04817f AC |
28137 | @var{packet-data} consists of a sequence of characters with the |
28138 | exception of @samp{#} and @samp{$} (see @samp{X} packet for additional | |
28139 | exceptions). | |
c906108c | 28140 | |
ee2d5c50 | 28141 | @cindex remote protocol, field separator |
0876f84a | 28142 | Fields within the packet should be separated using @samp{,} @samp{;} or |
8e04817f | 28143 | @samp{:}. Except where otherwise noted all numbers are represented in |
ee2d5c50 | 28144 | @sc{hex} with leading zeros suppressed. |
c906108c | 28145 | |
8e04817f AC |
28146 | Implementors should note that prior to @value{GDBN} 5.0, the character |
28147 | @samp{:} could not appear as the third character in a packet (as it | |
28148 | would potentially conflict with the @var{sequence-id}). | |
c906108c | 28149 | |
0876f84a DJ |
28150 | @cindex remote protocol, binary data |
28151 | @anchor{Binary Data} | |
28152 | Binary data in most packets is encoded either as two hexadecimal | |
28153 | digits per byte of binary data. This allowed the traditional remote | |
28154 | protocol to work over connections which were only seven-bit clean. | |
28155 | Some packets designed more recently assume an eight-bit clean | |
28156 | connection, and use a more efficient encoding to send and receive | |
28157 | binary data. | |
28158 | ||
28159 | The binary data representation uses @code{7d} (@sc{ascii} @samp{@}}) | |
28160 | as an escape character. Any escaped byte is transmitted as the escape | |
28161 | character followed by the original character XORed with @code{0x20}. | |
28162 | For example, the byte @code{0x7d} would be transmitted as the two | |
28163 | bytes @code{0x7d 0x5d}. The bytes @code{0x23} (@sc{ascii} @samp{#}), | |
28164 | @code{0x24} (@sc{ascii} @samp{$}), and @code{0x7d} (@sc{ascii} | |
28165 | @samp{@}}) must always be escaped. Responses sent by the stub | |
28166 | must also escape @code{0x2a} (@sc{ascii} @samp{*}), so that it | |
28167 | is not interpreted as the start of a run-length encoded sequence | |
28168 | (described next). | |
28169 | ||
1d3811f6 DJ |
28170 | Response @var{data} can be run-length encoded to save space. |
28171 | Run-length encoding replaces runs of identical characters with one | |
28172 | instance of the repeated character, followed by a @samp{*} and a | |
28173 | repeat count. The repeat count is itself sent encoded, to avoid | |
28174 | binary characters in @var{data}: a value of @var{n} is sent as | |
28175 | @code{@var{n}+29}. For a repeat count greater or equal to 3, this | |
28176 | produces a printable @sc{ascii} character, e.g.@: a space (@sc{ascii} | |
28177 | code 32) for a repeat count of 3. (This is because run-length | |
28178 | encoding starts to win for counts 3 or more.) Thus, for example, | |
28179 | @samp{0* } is a run-length encoding of ``0000'': the space character | |
28180 | after @samp{*} means repeat the leading @code{0} @w{@code{32 - 29 = | |
28181 | 3}} more times. | |
28182 | ||
28183 | The printable characters @samp{#} and @samp{$} or with a numeric value | |
28184 | greater than 126 must not be used. Runs of six repeats (@samp{#}) or | |
28185 | seven repeats (@samp{$}) can be expanded using a repeat count of only | |
28186 | five (@samp{"}). For example, @samp{00000000} can be encoded as | |
28187 | @samp{0*"00}. | |
c906108c | 28188 | |
8e04817f AC |
28189 | The error response returned for some packets includes a two character |
28190 | error number. That number is not well defined. | |
c906108c | 28191 | |
f8da2bff | 28192 | @cindex empty response, for unsupported packets |
8e04817f AC |
28193 | For any @var{command} not supported by the stub, an empty response |
28194 | (@samp{$#00}) should be returned. That way it is possible to extend the | |
28195 | protocol. A newer @value{GDBN} can tell if a packet is supported based | |
28196 | on that response. | |
c906108c | 28197 | |
b383017d RM |
28198 | A stub is required to support the @samp{g}, @samp{G}, @samp{m}, @samp{M}, |
28199 | @samp{c}, and @samp{s} @var{command}s. All other @var{command}s are | |
8e04817f | 28200 | optional. |
c906108c | 28201 | |
ee2d5c50 AC |
28202 | @node Packets |
28203 | @section Packets | |
28204 | ||
28205 | The following table provides a complete list of all currently defined | |
28206 | @var{command}s and their corresponding response @var{data}. | |
79a6e687 | 28207 | @xref{File-I/O Remote Protocol Extension}, for details about the File |
9c16f35a | 28208 | I/O extension of the remote protocol. |
ee2d5c50 | 28209 | |
b8ff78ce JB |
28210 | Each packet's description has a template showing the packet's overall |
28211 | syntax, followed by an explanation of the packet's meaning. We | |
28212 | include spaces in some of the templates for clarity; these are not | |
28213 | part of the packet's syntax. No @value{GDBN} packet uses spaces to | |
28214 | separate its components. For example, a template like @samp{foo | |
28215 | @var{bar} @var{baz}} describes a packet beginning with the three ASCII | |
28216 | bytes @samp{foo}, followed by a @var{bar}, followed directly by a | |
3f94c067 | 28217 | @var{baz}. @value{GDBN} does not transmit a space character between the |
b8ff78ce JB |
28218 | @samp{foo} and the @var{bar}, or between the @var{bar} and the |
28219 | @var{baz}. | |
28220 | ||
b90a069a SL |
28221 | @cindex @var{thread-id}, in remote protocol |
28222 | @anchor{thread-id syntax} | |
28223 | Several packets and replies include a @var{thread-id} field to identify | |
28224 | a thread. Normally these are positive numbers with a target-specific | |
28225 | interpretation, formatted as big-endian hex strings. A @var{thread-id} | |
28226 | can also be a literal @samp{-1} to indicate all threads, or @samp{0} to | |
28227 | pick any thread. | |
28228 | ||
28229 | In addition, the remote protocol supports a multiprocess feature in | |
28230 | which the @var{thread-id} syntax is extended to optionally include both | |
28231 | process and thread ID fields, as @samp{p@var{pid}.@var{tid}}. | |
28232 | The @var{pid} (process) and @var{tid} (thread) components each have the | |
28233 | format described above: a positive number with target-specific | |
28234 | interpretation formatted as a big-endian hex string, literal @samp{-1} | |
28235 | to indicate all processes or threads (respectively), or @samp{0} to | |
28236 | indicate an arbitrary process or thread. Specifying just a process, as | |
28237 | @samp{p@var{pid}}, is equivalent to @samp{p@var{pid}.-1}. It is an | |
28238 | error to specify all processes but a specific thread, such as | |
28239 | @samp{p-1.@var{tid}}. Note that the @samp{p} prefix is @emph{not} used | |
28240 | for those packets and replies explicitly documented to include a process | |
28241 | ID, rather than a @var{thread-id}. | |
28242 | ||
28243 | The multiprocess @var{thread-id} syntax extensions are only used if both | |
28244 | @value{GDBN} and the stub report support for the @samp{multiprocess} | |
28245 | feature using @samp{qSupported}. @xref{multiprocess extensions}, for | |
28246 | more information. | |
28247 | ||
8ffe2530 JB |
28248 | Note that all packet forms beginning with an upper- or lower-case |
28249 | letter, other than those described here, are reserved for future use. | |
28250 | ||
b8ff78ce | 28251 | Here are the packet descriptions. |
ee2d5c50 | 28252 | |
b8ff78ce | 28253 | @table @samp |
ee2d5c50 | 28254 | |
b8ff78ce JB |
28255 | @item ! |
28256 | @cindex @samp{!} packet | |
2d717e4f | 28257 | @anchor{extended mode} |
8e04817f AC |
28258 | Enable extended mode. In extended mode, the remote server is made |
28259 | persistent. The @samp{R} packet is used to restart the program being | |
28260 | debugged. | |
ee2d5c50 AC |
28261 | |
28262 | Reply: | |
28263 | @table @samp | |
28264 | @item OK | |
8e04817f | 28265 | The remote target both supports and has enabled extended mode. |
ee2d5c50 | 28266 | @end table |
c906108c | 28267 | |
b8ff78ce JB |
28268 | @item ? |
28269 | @cindex @samp{?} packet | |
ee2d5c50 | 28270 | Indicate the reason the target halted. The reply is the same as for |
8b23ecc4 SL |
28271 | step and continue. This packet has a special interpretation when the |
28272 | target is in non-stop mode; see @ref{Remote Non-Stop}. | |
c906108c | 28273 | |
ee2d5c50 AC |
28274 | Reply: |
28275 | @xref{Stop Reply Packets}, for the reply specifications. | |
28276 | ||
b8ff78ce JB |
28277 | @item A @var{arglen},@var{argnum},@var{arg},@dots{} |
28278 | @cindex @samp{A} packet | |
28279 | Initialized @code{argv[]} array passed into program. @var{arglen} | |
28280 | specifies the number of bytes in the hex encoded byte stream | |
28281 | @var{arg}. See @code{gdbserver} for more details. | |
ee2d5c50 AC |
28282 | |
28283 | Reply: | |
28284 | @table @samp | |
28285 | @item OK | |
b8ff78ce JB |
28286 | The arguments were set. |
28287 | @item E @var{NN} | |
28288 | An error occurred. | |
ee2d5c50 AC |
28289 | @end table |
28290 | ||
b8ff78ce JB |
28291 | @item b @var{baud} |
28292 | @cindex @samp{b} packet | |
28293 | (Don't use this packet; its behavior is not well-defined.) | |
ee2d5c50 AC |
28294 | Change the serial line speed to @var{baud}. |
28295 | ||
28296 | JTC: @emph{When does the transport layer state change? When it's | |
28297 | received, or after the ACK is transmitted. In either case, there are | |
28298 | problems if the command or the acknowledgment packet is dropped.} | |
28299 | ||
28300 | Stan: @emph{If people really wanted to add something like this, and get | |
28301 | it working for the first time, they ought to modify ser-unix.c to send | |
28302 | some kind of out-of-band message to a specially-setup stub and have the | |
28303 | switch happen "in between" packets, so that from remote protocol's point | |
28304 | of view, nothing actually happened.} | |
28305 | ||
b8ff78ce JB |
28306 | @item B @var{addr},@var{mode} |
28307 | @cindex @samp{B} packet | |
8e04817f | 28308 | Set (@var{mode} is @samp{S}) or clear (@var{mode} is @samp{C}) a |
2f870471 AC |
28309 | breakpoint at @var{addr}. |
28310 | ||
b8ff78ce | 28311 | Don't use this packet. Use the @samp{Z} and @samp{z} packets instead |
2f870471 | 28312 | (@pxref{insert breakpoint or watchpoint packet}). |
c906108c | 28313 | |
bacec72f | 28314 | @cindex @samp{bc} packet |
0d772ac9 MS |
28315 | @anchor{bc} |
28316 | @item bc | |
bacec72f MS |
28317 | Backward continue. Execute the target system in reverse. No parameter. |
28318 | @xref{Reverse Execution}, for more information. | |
28319 | ||
28320 | Reply: | |
28321 | @xref{Stop Reply Packets}, for the reply specifications. | |
28322 | ||
bacec72f | 28323 | @cindex @samp{bs} packet |
0d772ac9 MS |
28324 | @anchor{bs} |
28325 | @item bs | |
bacec72f MS |
28326 | Backward single step. Execute one instruction in reverse. No parameter. |
28327 | @xref{Reverse Execution}, for more information. | |
28328 | ||
28329 | Reply: | |
28330 | @xref{Stop Reply Packets}, for the reply specifications. | |
28331 | ||
4f553f88 | 28332 | @item c @r{[}@var{addr}@r{]} |
b8ff78ce JB |
28333 | @cindex @samp{c} packet |
28334 | Continue. @var{addr} is address to resume. If @var{addr} is omitted, | |
28335 | resume at current address. | |
c906108c | 28336 | |
ee2d5c50 AC |
28337 | Reply: |
28338 | @xref{Stop Reply Packets}, for the reply specifications. | |
28339 | ||
4f553f88 | 28340 | @item C @var{sig}@r{[};@var{addr}@r{]} |
b8ff78ce | 28341 | @cindex @samp{C} packet |
8e04817f | 28342 | Continue with signal @var{sig} (hex signal number). If |
b8ff78ce | 28343 | @samp{;@var{addr}} is omitted, resume at same address. |
c906108c | 28344 | |
ee2d5c50 AC |
28345 | Reply: |
28346 | @xref{Stop Reply Packets}, for the reply specifications. | |
c906108c | 28347 | |
b8ff78ce JB |
28348 | @item d |
28349 | @cindex @samp{d} packet | |
ee2d5c50 AC |
28350 | Toggle debug flag. |
28351 | ||
b8ff78ce JB |
28352 | Don't use this packet; instead, define a general set packet |
28353 | (@pxref{General Query Packets}). | |
ee2d5c50 | 28354 | |
b8ff78ce | 28355 | @item D |
b90a069a | 28356 | @itemx D;@var{pid} |
b8ff78ce | 28357 | @cindex @samp{D} packet |
b90a069a SL |
28358 | The first form of the packet is used to detach @value{GDBN} from the |
28359 | remote system. It is sent to the remote target | |
07f31aa6 | 28360 | before @value{GDBN} disconnects via the @code{detach} command. |
ee2d5c50 | 28361 | |
b90a069a SL |
28362 | The second form, including a process ID, is used when multiprocess |
28363 | protocol extensions are enabled (@pxref{multiprocess extensions}), to | |
28364 | detach only a specific process. The @var{pid} is specified as a | |
28365 | big-endian hex string. | |
28366 | ||
ee2d5c50 AC |
28367 | Reply: |
28368 | @table @samp | |
10fac096 NW |
28369 | @item OK |
28370 | for success | |
b8ff78ce | 28371 | @item E @var{NN} |
10fac096 | 28372 | for an error |
ee2d5c50 | 28373 | @end table |
c906108c | 28374 | |
b8ff78ce JB |
28375 | @item F @var{RC},@var{EE},@var{CF};@var{XX} |
28376 | @cindex @samp{F} packet | |
28377 | A reply from @value{GDBN} to an @samp{F} packet sent by the target. | |
28378 | This is part of the File-I/O protocol extension. @xref{File-I/O | |
79a6e687 | 28379 | Remote Protocol Extension}, for the specification. |
ee2d5c50 | 28380 | |
b8ff78ce | 28381 | @item g |
ee2d5c50 | 28382 | @anchor{read registers packet} |
b8ff78ce | 28383 | @cindex @samp{g} packet |
ee2d5c50 AC |
28384 | Read general registers. |
28385 | ||
28386 | Reply: | |
28387 | @table @samp | |
28388 | @item @var{XX@dots{}} | |
8e04817f AC |
28389 | Each byte of register data is described by two hex digits. The bytes |
28390 | with the register are transmitted in target byte order. The size of | |
b8ff78ce | 28391 | each register and their position within the @samp{g} packet are |
4a9bb1df UW |
28392 | determined by the @value{GDBN} internal gdbarch functions |
28393 | @code{DEPRECATED_REGISTER_RAW_SIZE} and @code{gdbarch_register_name}. The | |
b8ff78ce JB |
28394 | specification of several standard @samp{g} packets is specified below. |
28395 | @item E @var{NN} | |
ee2d5c50 AC |
28396 | for an error. |
28397 | @end table | |
c906108c | 28398 | |
b8ff78ce JB |
28399 | @item G @var{XX@dots{}} |
28400 | @cindex @samp{G} packet | |
28401 | Write general registers. @xref{read registers packet}, for a | |
28402 | description of the @var{XX@dots{}} data. | |
ee2d5c50 AC |
28403 | |
28404 | Reply: | |
28405 | @table @samp | |
28406 | @item OK | |
28407 | for success | |
b8ff78ce | 28408 | @item E @var{NN} |
ee2d5c50 AC |
28409 | for an error |
28410 | @end table | |
28411 | ||
b90a069a | 28412 | @item H @var{c} @var{thread-id} |
b8ff78ce | 28413 | @cindex @samp{H} packet |
8e04817f | 28414 | Set thread for subsequent operations (@samp{m}, @samp{M}, @samp{g}, |
ee2d5c50 AC |
28415 | @samp{G}, et.al.). @var{c} depends on the operation to be performed: it |
28416 | should be @samp{c} for step and continue operations, @samp{g} for other | |
b90a069a SL |
28417 | operations. The thread designator @var{thread-id} has the format and |
28418 | interpretation described in @ref{thread-id syntax}. | |
ee2d5c50 AC |
28419 | |
28420 | Reply: | |
28421 | @table @samp | |
28422 | @item OK | |
28423 | for success | |
b8ff78ce | 28424 | @item E @var{NN} |
ee2d5c50 AC |
28425 | for an error |
28426 | @end table | |
c906108c | 28427 | |
8e04817f AC |
28428 | @c FIXME: JTC: |
28429 | @c 'H': How restrictive (or permissive) is the thread model. If a | |
28430 | @c thread is selected and stopped, are other threads allowed | |
28431 | @c to continue to execute? As I mentioned above, I think the | |
28432 | @c semantics of each command when a thread is selected must be | |
28433 | @c described. For example: | |
28434 | @c | |
28435 | @c 'g': If the stub supports threads and a specific thread is | |
28436 | @c selected, returns the register block from that thread; | |
28437 | @c otherwise returns current registers. | |
28438 | @c | |
28439 | @c 'G' If the stub supports threads and a specific thread is | |
28440 | @c selected, sets the registers of the register block of | |
28441 | @c that thread; otherwise sets current registers. | |
c906108c | 28442 | |
b8ff78ce | 28443 | @item i @r{[}@var{addr}@r{[},@var{nnn}@r{]]} |
ee2d5c50 | 28444 | @anchor{cycle step packet} |
b8ff78ce JB |
28445 | @cindex @samp{i} packet |
28446 | Step the remote target by a single clock cycle. If @samp{,@var{nnn}} is | |
8e04817f AC |
28447 | present, cycle step @var{nnn} cycles. If @var{addr} is present, cycle |
28448 | step starting at that address. | |
c906108c | 28449 | |
b8ff78ce JB |
28450 | @item I |
28451 | @cindex @samp{I} packet | |
28452 | Signal, then cycle step. @xref{step with signal packet}. @xref{cycle | |
28453 | step packet}. | |
ee2d5c50 | 28454 | |
b8ff78ce JB |
28455 | @item k |
28456 | @cindex @samp{k} packet | |
28457 | Kill request. | |
c906108c | 28458 | |
ac282366 | 28459 | FIXME: @emph{There is no description of how to operate when a specific |
ee2d5c50 AC |
28460 | thread context has been selected (i.e.@: does 'k' kill only that |
28461 | thread?)}. | |
c906108c | 28462 | |
b8ff78ce JB |
28463 | @item m @var{addr},@var{length} |
28464 | @cindex @samp{m} packet | |
8e04817f | 28465 | Read @var{length} bytes of memory starting at address @var{addr}. |
fb031cdf JB |
28466 | Note that @var{addr} may not be aligned to any particular boundary. |
28467 | ||
28468 | The stub need not use any particular size or alignment when gathering | |
28469 | data from memory for the response; even if @var{addr} is word-aligned | |
28470 | and @var{length} is a multiple of the word size, the stub is free to | |
28471 | use byte accesses, or not. For this reason, this packet may not be | |
28472 | suitable for accessing memory-mapped I/O devices. | |
c43c5473 JB |
28473 | @cindex alignment of remote memory accesses |
28474 | @cindex size of remote memory accesses | |
28475 | @cindex memory, alignment and size of remote accesses | |
c906108c | 28476 | |
ee2d5c50 AC |
28477 | Reply: |
28478 | @table @samp | |
28479 | @item @var{XX@dots{}} | |
599b237a | 28480 | Memory contents; each byte is transmitted as a two-digit hexadecimal |
b8ff78ce JB |
28481 | number. The reply may contain fewer bytes than requested if the |
28482 | server was able to read only part of the region of memory. | |
28483 | @item E @var{NN} | |
ee2d5c50 AC |
28484 | @var{NN} is errno |
28485 | @end table | |
28486 | ||
b8ff78ce JB |
28487 | @item M @var{addr},@var{length}:@var{XX@dots{}} |
28488 | @cindex @samp{M} packet | |
8e04817f | 28489 | Write @var{length} bytes of memory starting at address @var{addr}. |
b8ff78ce | 28490 | @var{XX@dots{}} is the data; each byte is transmitted as a two-digit |
599b237a | 28491 | hexadecimal number. |
ee2d5c50 AC |
28492 | |
28493 | Reply: | |
28494 | @table @samp | |
28495 | @item OK | |
28496 | for success | |
b8ff78ce | 28497 | @item E @var{NN} |
8e04817f AC |
28498 | for an error (this includes the case where only part of the data was |
28499 | written). | |
ee2d5c50 | 28500 | @end table |
c906108c | 28501 | |
b8ff78ce JB |
28502 | @item p @var{n} |
28503 | @cindex @samp{p} packet | |
28504 | Read the value of register @var{n}; @var{n} is in hex. | |
2e868123 AC |
28505 | @xref{read registers packet}, for a description of how the returned |
28506 | register value is encoded. | |
ee2d5c50 AC |
28507 | |
28508 | Reply: | |
28509 | @table @samp | |
2e868123 AC |
28510 | @item @var{XX@dots{}} |
28511 | the register's value | |
b8ff78ce | 28512 | @item E @var{NN} |
2e868123 AC |
28513 | for an error |
28514 | @item | |
28515 | Indicating an unrecognized @var{query}. | |
ee2d5c50 AC |
28516 | @end table |
28517 | ||
b8ff78ce | 28518 | @item P @var{n@dots{}}=@var{r@dots{}} |
ee2d5c50 | 28519 | @anchor{write register packet} |
b8ff78ce JB |
28520 | @cindex @samp{P} packet |
28521 | Write register @var{n@dots{}} with value @var{r@dots{}}. The register | |
599b237a | 28522 | number @var{n} is in hexadecimal, and @var{r@dots{}} contains two hex |
8e04817f | 28523 | digits for each byte in the register (target byte order). |
c906108c | 28524 | |
ee2d5c50 AC |
28525 | Reply: |
28526 | @table @samp | |
28527 | @item OK | |
28528 | for success | |
b8ff78ce | 28529 | @item E @var{NN} |
ee2d5c50 AC |
28530 | for an error |
28531 | @end table | |
28532 | ||
5f3bebba JB |
28533 | @item q @var{name} @var{params}@dots{} |
28534 | @itemx Q @var{name} @var{params}@dots{} | |
b8ff78ce | 28535 | @cindex @samp{q} packet |
b8ff78ce | 28536 | @cindex @samp{Q} packet |
5f3bebba JB |
28537 | General query (@samp{q}) and set (@samp{Q}). These packets are |
28538 | described fully in @ref{General Query Packets}. | |
c906108c | 28539 | |
b8ff78ce JB |
28540 | @item r |
28541 | @cindex @samp{r} packet | |
8e04817f | 28542 | Reset the entire system. |
c906108c | 28543 | |
b8ff78ce | 28544 | Don't use this packet; use the @samp{R} packet instead. |
ee2d5c50 | 28545 | |
b8ff78ce JB |
28546 | @item R @var{XX} |
28547 | @cindex @samp{R} packet | |
8e04817f | 28548 | Restart the program being debugged. @var{XX}, while needed, is ignored. |
2d717e4f | 28549 | This packet is only available in extended mode (@pxref{extended mode}). |
ee2d5c50 | 28550 | |
8e04817f | 28551 | The @samp{R} packet has no reply. |
ee2d5c50 | 28552 | |
4f553f88 | 28553 | @item s @r{[}@var{addr}@r{]} |
b8ff78ce JB |
28554 | @cindex @samp{s} packet |
28555 | Single step. @var{addr} is the address at which to resume. If | |
28556 | @var{addr} is omitted, resume at same address. | |
c906108c | 28557 | |
ee2d5c50 AC |
28558 | Reply: |
28559 | @xref{Stop Reply Packets}, for the reply specifications. | |
28560 | ||
4f553f88 | 28561 | @item S @var{sig}@r{[};@var{addr}@r{]} |
ee2d5c50 | 28562 | @anchor{step with signal packet} |
b8ff78ce JB |
28563 | @cindex @samp{S} packet |
28564 | Step with signal. This is analogous to the @samp{C} packet, but | |
28565 | requests a single-step, rather than a normal resumption of execution. | |
c906108c | 28566 | |
ee2d5c50 AC |
28567 | Reply: |
28568 | @xref{Stop Reply Packets}, for the reply specifications. | |
28569 | ||
b8ff78ce JB |
28570 | @item t @var{addr}:@var{PP},@var{MM} |
28571 | @cindex @samp{t} packet | |
8e04817f | 28572 | Search backwards starting at address @var{addr} for a match with pattern |
ee2d5c50 AC |
28573 | @var{PP} and mask @var{MM}. @var{PP} and @var{MM} are 4 bytes. |
28574 | @var{addr} must be at least 3 digits. | |
c906108c | 28575 | |
b90a069a | 28576 | @item T @var{thread-id} |
b8ff78ce | 28577 | @cindex @samp{T} packet |
b90a069a | 28578 | Find out if the thread @var{thread-id} is alive. @xref{thread-id syntax}. |
c906108c | 28579 | |
ee2d5c50 AC |
28580 | Reply: |
28581 | @table @samp | |
28582 | @item OK | |
28583 | thread is still alive | |
b8ff78ce | 28584 | @item E @var{NN} |
ee2d5c50 AC |
28585 | thread is dead |
28586 | @end table | |
28587 | ||
b8ff78ce JB |
28588 | @item v |
28589 | Packets starting with @samp{v} are identified by a multi-letter name, | |
28590 | up to the first @samp{;} or @samp{?} (or the end of the packet). | |
86d30acc | 28591 | |
2d717e4f DJ |
28592 | @item vAttach;@var{pid} |
28593 | @cindex @samp{vAttach} packet | |
8b23ecc4 SL |
28594 | Attach to a new process with the specified process ID @var{pid}. |
28595 | The process ID is a | |
28596 | hexadecimal integer identifying the process. In all-stop mode, all | |
28597 | threads in the attached process are stopped; in non-stop mode, it may be | |
28598 | attached without being stopped if that is supported by the target. | |
28599 | ||
28600 | @c In non-stop mode, on a successful vAttach, the stub should set the | |
28601 | @c current thread to a thread of the newly-attached process. After | |
28602 | @c attaching, GDB queries for the attached process's thread ID with qC. | |
28603 | @c Also note that, from a user perspective, whether or not the | |
28604 | @c target is stopped on attach in non-stop mode depends on whether you | |
28605 | @c use the foreground or background version of the attach command, not | |
28606 | @c on what vAttach does; GDB does the right thing with respect to either | |
28607 | @c stopping or restarting threads. | |
2d717e4f DJ |
28608 | |
28609 | This packet is only available in extended mode (@pxref{extended mode}). | |
28610 | ||
28611 | Reply: | |
28612 | @table @samp | |
28613 | @item E @var{nn} | |
28614 | for an error | |
28615 | @item @r{Any stop packet} | |
8b23ecc4 SL |
28616 | for success in all-stop mode (@pxref{Stop Reply Packets}) |
28617 | @item OK | |
28618 | for success in non-stop mode (@pxref{Remote Non-Stop}) | |
2d717e4f DJ |
28619 | @end table |
28620 | ||
b90a069a | 28621 | @item vCont@r{[};@var{action}@r{[}:@var{thread-id}@r{]]}@dots{} |
b8ff78ce JB |
28622 | @cindex @samp{vCont} packet |
28623 | Resume the inferior, specifying different actions for each thread. | |
b90a069a | 28624 | If an action is specified with no @var{thread-id}, then it is applied to any |
86d30acc | 28625 | threads that don't have a specific action specified; if no default action is |
8b23ecc4 SL |
28626 | specified then other threads should remain stopped in all-stop mode and |
28627 | in their current state in non-stop mode. | |
28628 | Specifying multiple | |
86d30acc | 28629 | default actions is an error; specifying no actions is also an error. |
b90a069a SL |
28630 | Thread IDs are specified using the syntax described in @ref{thread-id syntax}. |
28631 | ||
28632 | Currently supported actions are: | |
86d30acc | 28633 | |
b8ff78ce | 28634 | @table @samp |
86d30acc DJ |
28635 | @item c |
28636 | Continue. | |
b8ff78ce | 28637 | @item C @var{sig} |
8b23ecc4 | 28638 | Continue with signal @var{sig}. The signal @var{sig} should be two hex digits. |
86d30acc DJ |
28639 | @item s |
28640 | Step. | |
b8ff78ce | 28641 | @item S @var{sig} |
8b23ecc4 SL |
28642 | Step with signal @var{sig}. The signal @var{sig} should be two hex digits. |
28643 | @item t | |
28644 | Stop. | |
86d30acc DJ |
28645 | @end table |
28646 | ||
8b23ecc4 SL |
28647 | The optional argument @var{addr} normally associated with the |
28648 | @samp{c}, @samp{C}, @samp{s}, and @samp{S} packets is | |
b8ff78ce | 28649 | not supported in @samp{vCont}. |
86d30acc | 28650 | |
08a0efd0 PA |
28651 | The @samp{t} action is only relevant in non-stop mode |
28652 | (@pxref{Remote Non-Stop}) and may be ignored by the stub otherwise. | |
8b23ecc4 SL |
28653 | A stop reply should be generated for any affected thread not already stopped. |
28654 | When a thread is stopped by means of a @samp{t} action, | |
28655 | the corresponding stop reply should indicate that the thread has stopped with | |
28656 | signal @samp{0}, regardless of whether the target uses some other signal | |
28657 | as an implementation detail. | |
28658 | ||
86d30acc DJ |
28659 | Reply: |
28660 | @xref{Stop Reply Packets}, for the reply specifications. | |
28661 | ||
b8ff78ce JB |
28662 | @item vCont? |
28663 | @cindex @samp{vCont?} packet | |
d3e8051b | 28664 | Request a list of actions supported by the @samp{vCont} packet. |
86d30acc DJ |
28665 | |
28666 | Reply: | |
28667 | @table @samp | |
b8ff78ce JB |
28668 | @item vCont@r{[};@var{action}@dots{}@r{]} |
28669 | The @samp{vCont} packet is supported. Each @var{action} is a supported | |
28670 | command in the @samp{vCont} packet. | |
86d30acc | 28671 | @item |
b8ff78ce | 28672 | The @samp{vCont} packet is not supported. |
86d30acc | 28673 | @end table |
ee2d5c50 | 28674 | |
a6b151f1 DJ |
28675 | @item vFile:@var{operation}:@var{parameter}@dots{} |
28676 | @cindex @samp{vFile} packet | |
28677 | Perform a file operation on the target system. For details, | |
28678 | see @ref{Host I/O Packets}. | |
28679 | ||
68437a39 DJ |
28680 | @item vFlashErase:@var{addr},@var{length} |
28681 | @cindex @samp{vFlashErase} packet | |
28682 | Direct the stub to erase @var{length} bytes of flash starting at | |
28683 | @var{addr}. The region may enclose any number of flash blocks, but | |
28684 | its start and end must fall on block boundaries, as indicated by the | |
79a6e687 BW |
28685 | flash block size appearing in the memory map (@pxref{Memory Map |
28686 | Format}). @value{GDBN} groups flash memory programming operations | |
68437a39 DJ |
28687 | together, and sends a @samp{vFlashDone} request after each group; the |
28688 | stub is allowed to delay erase operation until the @samp{vFlashDone} | |
28689 | packet is received. | |
28690 | ||
b90a069a SL |
28691 | The stub must support @samp{vCont} if it reports support for |
28692 | multiprocess extensions (@pxref{multiprocess extensions}). Note that in | |
28693 | this case @samp{vCont} actions can be specified to apply to all threads | |
28694 | in a process by using the @samp{p@var{pid}.-1} form of the | |
28695 | @var{thread-id}. | |
28696 | ||
68437a39 DJ |
28697 | Reply: |
28698 | @table @samp | |
28699 | @item OK | |
28700 | for success | |
28701 | @item E @var{NN} | |
28702 | for an error | |
28703 | @end table | |
28704 | ||
28705 | @item vFlashWrite:@var{addr}:@var{XX@dots{}} | |
28706 | @cindex @samp{vFlashWrite} packet | |
28707 | Direct the stub to write data to flash address @var{addr}. The data | |
28708 | is passed in binary form using the same encoding as for the @samp{X} | |
28709 | packet (@pxref{Binary Data}). The memory ranges specified by | |
28710 | @samp{vFlashWrite} packets preceding a @samp{vFlashDone} packet must | |
28711 | not overlap, and must appear in order of increasing addresses | |
28712 | (although @samp{vFlashErase} packets for higher addresses may already | |
28713 | have been received; the ordering is guaranteed only between | |
28714 | @samp{vFlashWrite} packets). If a packet writes to an address that was | |
28715 | neither erased by a preceding @samp{vFlashErase} packet nor by some other | |
28716 | target-specific method, the results are unpredictable. | |
28717 | ||
28718 | ||
28719 | Reply: | |
28720 | @table @samp | |
28721 | @item OK | |
28722 | for success | |
28723 | @item E.memtype | |
28724 | for vFlashWrite addressing non-flash memory | |
28725 | @item E @var{NN} | |
28726 | for an error | |
28727 | @end table | |
28728 | ||
28729 | @item vFlashDone | |
28730 | @cindex @samp{vFlashDone} packet | |
28731 | Indicate to the stub that flash programming operation is finished. | |
28732 | The stub is permitted to delay or batch the effects of a group of | |
28733 | @samp{vFlashErase} and @samp{vFlashWrite} packets until a | |
28734 | @samp{vFlashDone} packet is received. The contents of the affected | |
28735 | regions of flash memory are unpredictable until the @samp{vFlashDone} | |
28736 | request is completed. | |
28737 | ||
b90a069a SL |
28738 | @item vKill;@var{pid} |
28739 | @cindex @samp{vKill} packet | |
28740 | Kill the process with the specified process ID. @var{pid} is a | |
28741 | hexadecimal integer identifying the process. This packet is used in | |
28742 | preference to @samp{k} when multiprocess protocol extensions are | |
28743 | supported; see @ref{multiprocess extensions}. | |
28744 | ||
28745 | Reply: | |
28746 | @table @samp | |
28747 | @item E @var{nn} | |
28748 | for an error | |
28749 | @item OK | |
28750 | for success | |
28751 | @end table | |
28752 | ||
2d717e4f DJ |
28753 | @item vRun;@var{filename}@r{[};@var{argument}@r{]}@dots{} |
28754 | @cindex @samp{vRun} packet | |
28755 | Run the program @var{filename}, passing it each @var{argument} on its | |
28756 | command line. The file and arguments are hex-encoded strings. If | |
28757 | @var{filename} is an empty string, the stub may use a default program | |
28758 | (e.g.@: the last program run). The program is created in the stopped | |
9b562ab8 | 28759 | state. |
2d717e4f | 28760 | |
8b23ecc4 SL |
28761 | @c FIXME: What about non-stop mode? |
28762 | ||
2d717e4f DJ |
28763 | This packet is only available in extended mode (@pxref{extended mode}). |
28764 | ||
28765 | Reply: | |
28766 | @table @samp | |
28767 | @item E @var{nn} | |
28768 | for an error | |
28769 | @item @r{Any stop packet} | |
28770 | for success (@pxref{Stop Reply Packets}) | |
28771 | @end table | |
28772 | ||
8b23ecc4 SL |
28773 | @item vStopped |
28774 | @anchor{vStopped packet} | |
28775 | @cindex @samp{vStopped} packet | |
28776 | ||
28777 | In non-stop mode (@pxref{Remote Non-Stop}), acknowledge a previous stop | |
28778 | reply and prompt for the stub to report another one. | |
28779 | ||
28780 | Reply: | |
28781 | @table @samp | |
28782 | @item @r{Any stop packet} | |
28783 | if there is another unreported stop event (@pxref{Stop Reply Packets}) | |
28784 | @item OK | |
28785 | if there are no unreported stop events | |
28786 | @end table | |
28787 | ||
b8ff78ce | 28788 | @item X @var{addr},@var{length}:@var{XX@dots{}} |
9a6253be | 28789 | @anchor{X packet} |
b8ff78ce JB |
28790 | @cindex @samp{X} packet |
28791 | Write data to memory, where the data is transmitted in binary. | |
28792 | @var{addr} is address, @var{length} is number of bytes, | |
0876f84a | 28793 | @samp{@var{XX}@dots{}} is binary data (@pxref{Binary Data}). |
c906108c | 28794 | |
ee2d5c50 AC |
28795 | Reply: |
28796 | @table @samp | |
28797 | @item OK | |
28798 | for success | |
b8ff78ce | 28799 | @item E @var{NN} |
ee2d5c50 AC |
28800 | for an error |
28801 | @end table | |
28802 | ||
b8ff78ce JB |
28803 | @item z @var{type},@var{addr},@var{length} |
28804 | @itemx Z @var{type},@var{addr},@var{length} | |
2f870471 | 28805 | @anchor{insert breakpoint or watchpoint packet} |
b8ff78ce JB |
28806 | @cindex @samp{z} packet |
28807 | @cindex @samp{Z} packets | |
28808 | Insert (@samp{Z}) or remove (@samp{z}) a @var{type} breakpoint or | |
2f870471 AC |
28809 | watchpoint starting at address @var{address} and covering the next |
28810 | @var{length} bytes. | |
ee2d5c50 | 28811 | |
2f870471 AC |
28812 | Each breakpoint and watchpoint packet @var{type} is documented |
28813 | separately. | |
28814 | ||
512217c7 AC |
28815 | @emph{Implementation notes: A remote target shall return an empty string |
28816 | for an unrecognized breakpoint or watchpoint packet @var{type}. A | |
28817 | remote target shall support either both or neither of a given | |
b8ff78ce | 28818 | @samp{Z@var{type}@dots{}} and @samp{z@var{type}@dots{}} packet pair. To |
2f870471 AC |
28819 | avoid potential problems with duplicate packets, the operations should |
28820 | be implemented in an idempotent way.} | |
28821 | ||
b8ff78ce JB |
28822 | @item z0,@var{addr},@var{length} |
28823 | @itemx Z0,@var{addr},@var{length} | |
28824 | @cindex @samp{z0} packet | |
28825 | @cindex @samp{Z0} packet | |
28826 | Insert (@samp{Z0}) or remove (@samp{z0}) a memory breakpoint at address | |
28827 | @var{addr} of size @var{length}. | |
2f870471 AC |
28828 | |
28829 | A memory breakpoint is implemented by replacing the instruction at | |
28830 | @var{addr} with a software breakpoint or trap instruction. The | |
b8ff78ce | 28831 | @var{length} is used by targets that indicates the size of the |
2f870471 AC |
28832 | breakpoint (in bytes) that should be inserted (e.g., the @sc{arm} and |
28833 | @sc{mips} can insert either a 2 or 4 byte breakpoint). | |
c906108c | 28834 | |
2f870471 AC |
28835 | @emph{Implementation note: It is possible for a target to copy or move |
28836 | code that contains memory breakpoints (e.g., when implementing | |
28837 | overlays). The behavior of this packet, in the presence of such a | |
28838 | target, is not defined.} | |
c906108c | 28839 | |
ee2d5c50 AC |
28840 | Reply: |
28841 | @table @samp | |
2f870471 AC |
28842 | @item OK |
28843 | success | |
28844 | @item | |
28845 | not supported | |
b8ff78ce | 28846 | @item E @var{NN} |
ee2d5c50 | 28847 | for an error |
2f870471 AC |
28848 | @end table |
28849 | ||
b8ff78ce JB |
28850 | @item z1,@var{addr},@var{length} |
28851 | @itemx Z1,@var{addr},@var{length} | |
28852 | @cindex @samp{z1} packet | |
28853 | @cindex @samp{Z1} packet | |
28854 | Insert (@samp{Z1}) or remove (@samp{z1}) a hardware breakpoint at | |
28855 | address @var{addr} of size @var{length}. | |
2f870471 AC |
28856 | |
28857 | A hardware breakpoint is implemented using a mechanism that is not | |
28858 | dependant on being able to modify the target's memory. | |
28859 | ||
28860 | @emph{Implementation note: A hardware breakpoint is not affected by code | |
28861 | movement.} | |
28862 | ||
28863 | Reply: | |
28864 | @table @samp | |
ee2d5c50 | 28865 | @item OK |
2f870471 AC |
28866 | success |
28867 | @item | |
28868 | not supported | |
b8ff78ce | 28869 | @item E @var{NN} |
2f870471 AC |
28870 | for an error |
28871 | @end table | |
28872 | ||
b8ff78ce JB |
28873 | @item z2,@var{addr},@var{length} |
28874 | @itemx Z2,@var{addr},@var{length} | |
28875 | @cindex @samp{z2} packet | |
28876 | @cindex @samp{Z2} packet | |
28877 | Insert (@samp{Z2}) or remove (@samp{z2}) a write watchpoint. | |
2f870471 AC |
28878 | |
28879 | Reply: | |
28880 | @table @samp | |
28881 | @item OK | |
28882 | success | |
28883 | @item | |
28884 | not supported | |
b8ff78ce | 28885 | @item E @var{NN} |
2f870471 AC |
28886 | for an error |
28887 | @end table | |
28888 | ||
b8ff78ce JB |
28889 | @item z3,@var{addr},@var{length} |
28890 | @itemx Z3,@var{addr},@var{length} | |
28891 | @cindex @samp{z3} packet | |
28892 | @cindex @samp{Z3} packet | |
28893 | Insert (@samp{Z3}) or remove (@samp{z3}) a read watchpoint. | |
2f870471 AC |
28894 | |
28895 | Reply: | |
28896 | @table @samp | |
28897 | @item OK | |
28898 | success | |
28899 | @item | |
28900 | not supported | |
b8ff78ce | 28901 | @item E @var{NN} |
2f870471 AC |
28902 | for an error |
28903 | @end table | |
28904 | ||
b8ff78ce JB |
28905 | @item z4,@var{addr},@var{length} |
28906 | @itemx Z4,@var{addr},@var{length} | |
28907 | @cindex @samp{z4} packet | |
28908 | @cindex @samp{Z4} packet | |
28909 | Insert (@samp{Z4}) or remove (@samp{z4}) an access watchpoint. | |
2f870471 AC |
28910 | |
28911 | Reply: | |
28912 | @table @samp | |
28913 | @item OK | |
28914 | success | |
28915 | @item | |
28916 | not supported | |
b8ff78ce | 28917 | @item E @var{NN} |
2f870471 | 28918 | for an error |
ee2d5c50 AC |
28919 | @end table |
28920 | ||
28921 | @end table | |
c906108c | 28922 | |
ee2d5c50 AC |
28923 | @node Stop Reply Packets |
28924 | @section Stop Reply Packets | |
28925 | @cindex stop reply packets | |
c906108c | 28926 | |
8b23ecc4 SL |
28927 | The @samp{C}, @samp{c}, @samp{S}, @samp{s}, @samp{vCont}, |
28928 | @samp{vAttach}, @samp{vRun}, @samp{vStopped}, and @samp{?} packets can | |
28929 | receive any of the below as a reply. Except for @samp{?} | |
28930 | and @samp{vStopped}, that reply is only returned | |
b8ff78ce | 28931 | when the target halts. In the below the exact meaning of @dfn{signal |
89be2091 DJ |
28932 | number} is defined by the header @file{include/gdb/signals.h} in the |
28933 | @value{GDBN} source code. | |
c906108c | 28934 | |
b8ff78ce JB |
28935 | As in the description of request packets, we include spaces in the |
28936 | reply templates for clarity; these are not part of the reply packet's | |
28937 | syntax. No @value{GDBN} stop reply packet uses spaces to separate its | |
28938 | components. | |
c906108c | 28939 | |
b8ff78ce | 28940 | @table @samp |
ee2d5c50 | 28941 | |
b8ff78ce | 28942 | @item S @var{AA} |
599b237a | 28943 | The program received signal number @var{AA} (a two-digit hexadecimal |
940178d3 JB |
28944 | number). This is equivalent to a @samp{T} response with no |
28945 | @var{n}:@var{r} pairs. | |
c906108c | 28946 | |
b8ff78ce JB |
28947 | @item T @var{AA} @var{n1}:@var{r1};@var{n2}:@var{r2};@dots{} |
28948 | @cindex @samp{T} packet reply | |
599b237a | 28949 | The program received signal number @var{AA} (a two-digit hexadecimal |
940178d3 JB |
28950 | number). This is equivalent to an @samp{S} response, except that the |
28951 | @samp{@var{n}:@var{r}} pairs can carry values of important registers | |
28952 | and other information directly in the stop reply packet, reducing | |
28953 | round-trip latency. Single-step and breakpoint traps are reported | |
28954 | this way. Each @samp{@var{n}:@var{r}} pair is interpreted as follows: | |
cfa9d6d9 DJ |
28955 | |
28956 | @itemize @bullet | |
b8ff78ce | 28957 | @item |
599b237a | 28958 | If @var{n} is a hexadecimal number, it is a register number, and the |
b8ff78ce JB |
28959 | corresponding @var{r} gives that register's value. @var{r} is a |
28960 | series of bytes in target byte order, with each byte given by a | |
28961 | two-digit hex number. | |
cfa9d6d9 | 28962 | |
b8ff78ce | 28963 | @item |
b90a069a SL |
28964 | If @var{n} is @samp{thread}, then @var{r} is the @var{thread-id} of |
28965 | the stopped thread, as specified in @ref{thread-id syntax}. | |
cfa9d6d9 | 28966 | |
b8ff78ce | 28967 | @item |
cfa9d6d9 DJ |
28968 | If @var{n} is a recognized @dfn{stop reason}, it describes a more |
28969 | specific event that stopped the target. The currently defined stop | |
28970 | reasons are listed below. @var{aa} should be @samp{05}, the trap | |
28971 | signal. At most one stop reason should be present. | |
28972 | ||
b8ff78ce JB |
28973 | @item |
28974 | Otherwise, @value{GDBN} should ignore this @samp{@var{n}:@var{r}} pair | |
28975 | and go on to the next; this allows us to extend the protocol in the | |
28976 | future. | |
cfa9d6d9 DJ |
28977 | @end itemize |
28978 | ||
28979 | The currently defined stop reasons are: | |
28980 | ||
28981 | @table @samp | |
28982 | @item watch | |
28983 | @itemx rwatch | |
28984 | @itemx awatch | |
28985 | The packet indicates a watchpoint hit, and @var{r} is the data address, in | |
28986 | hex. | |
28987 | ||
28988 | @cindex shared library events, remote reply | |
28989 | @item library | |
28990 | The packet indicates that the loaded libraries have changed. | |
28991 | @value{GDBN} should use @samp{qXfer:libraries:read} to fetch a new | |
28992 | list of loaded libraries. @var{r} is ignored. | |
bacec72f MS |
28993 | |
28994 | @cindex replay log events, remote reply | |
28995 | @item replaylog | |
28996 | The packet indicates that the target cannot continue replaying | |
28997 | logged execution events, because it has reached the end (or the | |
28998 | beginning when executing backward) of the log. The value of @var{r} | |
28999 | will be either @samp{begin} or @samp{end}. @xref{Reverse Execution}, | |
29000 | for more information. | |
29001 | ||
29002 | ||
cfa9d6d9 | 29003 | @end table |
ee2d5c50 | 29004 | |
b8ff78ce | 29005 | @item W @var{AA} |
b90a069a | 29006 | @itemx W @var{AA} ; process:@var{pid} |
8e04817f | 29007 | The process exited, and @var{AA} is the exit status. This is only |
ee2d5c50 AC |
29008 | applicable to certain targets. |
29009 | ||
b90a069a SL |
29010 | The second form of the response, including the process ID of the exited |
29011 | process, can be used only when @value{GDBN} has reported support for | |
29012 | multiprocess protocol extensions; see @ref{multiprocess extensions}. | |
29013 | The @var{pid} is formatted as a big-endian hex string. | |
29014 | ||
b8ff78ce | 29015 | @item X @var{AA} |
b90a069a | 29016 | @itemx X @var{AA} ; process:@var{pid} |
8e04817f | 29017 | The process terminated with signal @var{AA}. |
c906108c | 29018 | |
b90a069a SL |
29019 | The second form of the response, including the process ID of the |
29020 | terminated process, can be used only when @value{GDBN} has reported | |
29021 | support for multiprocess protocol extensions; see @ref{multiprocess | |
29022 | extensions}. The @var{pid} is formatted as a big-endian hex string. | |
29023 | ||
b8ff78ce JB |
29024 | @item O @var{XX}@dots{} |
29025 | @samp{@var{XX}@dots{}} is hex encoding of @sc{ascii} data, to be | |
29026 | written as the program's console output. This can happen at any time | |
29027 | while the program is running and the debugger should continue to wait | |
8b23ecc4 | 29028 | for @samp{W}, @samp{T}, etc. This reply is not permitted in non-stop mode. |
0ce1b118 | 29029 | |
b8ff78ce | 29030 | @item F @var{call-id},@var{parameter}@dots{} |
0ce1b118 CV |
29031 | @var{call-id} is the identifier which says which host system call should |
29032 | be called. This is just the name of the function. Translation into the | |
29033 | correct system call is only applicable as it's defined in @value{GDBN}. | |
79a6e687 | 29034 | @xref{File-I/O Remote Protocol Extension}, for a list of implemented |
0ce1b118 CV |
29035 | system calls. |
29036 | ||
b8ff78ce JB |
29037 | @samp{@var{parameter}@dots{}} is a list of parameters as defined for |
29038 | this very system call. | |
0ce1b118 | 29039 | |
b8ff78ce JB |
29040 | The target replies with this packet when it expects @value{GDBN} to |
29041 | call a host system call on behalf of the target. @value{GDBN} replies | |
29042 | with an appropriate @samp{F} packet and keeps up waiting for the next | |
29043 | reply packet from the target. The latest @samp{C}, @samp{c}, @samp{S} | |
79a6e687 BW |
29044 | or @samp{s} action is expected to be continued. @xref{File-I/O Remote |
29045 | Protocol Extension}, for more details. | |
0ce1b118 | 29046 | |
ee2d5c50 AC |
29047 | @end table |
29048 | ||
29049 | @node General Query Packets | |
29050 | @section General Query Packets | |
9c16f35a | 29051 | @cindex remote query requests |
c906108c | 29052 | |
5f3bebba JB |
29053 | Packets starting with @samp{q} are @dfn{general query packets}; |
29054 | packets starting with @samp{Q} are @dfn{general set packets}. General | |
29055 | query and set packets are a semi-unified form for retrieving and | |
29056 | sending information to and from the stub. | |
29057 | ||
29058 | The initial letter of a query or set packet is followed by a name | |
29059 | indicating what sort of thing the packet applies to. For example, | |
29060 | @value{GDBN} may use a @samp{qSymbol} packet to exchange symbol | |
29061 | definitions with the stub. These packet names follow some | |
29062 | conventions: | |
29063 | ||
29064 | @itemize @bullet | |
29065 | @item | |
29066 | The name must not contain commas, colons or semicolons. | |
29067 | @item | |
29068 | Most @value{GDBN} query and set packets have a leading upper case | |
29069 | letter. | |
29070 | @item | |
29071 | The names of custom vendor packets should use a company prefix, in | |
29072 | lower case, followed by a period. For example, packets designed at | |
29073 | the Acme Corporation might begin with @samp{qacme.foo} (for querying | |
29074 | foos) or @samp{Qacme.bar} (for setting bars). | |
29075 | @end itemize | |
29076 | ||
aa56d27a JB |
29077 | The name of a query or set packet should be separated from any |
29078 | parameters by a @samp{:}; the parameters themselves should be | |
29079 | separated by @samp{,} or @samp{;}. Stubs must be careful to match the | |
369af7bd DJ |
29080 | full packet name, and check for a separator or the end of the packet, |
29081 | in case two packet names share a common prefix. New packets should not begin | |
29082 | with @samp{qC}, @samp{qP}, or @samp{qL}@footnote{The @samp{qP} and @samp{qL} | |
29083 | packets predate these conventions, and have arguments without any terminator | |
29084 | for the packet name; we suspect they are in widespread use in places that | |
29085 | are difficult to upgrade. The @samp{qC} packet has no arguments, but some | |
29086 | existing stubs (e.g.@: RedBoot) are known to not check for the end of the | |
29087 | packet.}. | |
c906108c | 29088 | |
b8ff78ce JB |
29089 | Like the descriptions of the other packets, each description here |
29090 | has a template showing the packet's overall syntax, followed by an | |
29091 | explanation of the packet's meaning. We include spaces in some of the | |
29092 | templates for clarity; these are not part of the packet's syntax. No | |
29093 | @value{GDBN} packet uses spaces to separate its components. | |
29094 | ||
5f3bebba JB |
29095 | Here are the currently defined query and set packets: |
29096 | ||
b8ff78ce | 29097 | @table @samp |
c906108c | 29098 | |
b8ff78ce | 29099 | @item qC |
9c16f35a | 29100 | @cindex current thread, remote request |
b8ff78ce | 29101 | @cindex @samp{qC} packet |
b90a069a | 29102 | Return the current thread ID. |
ee2d5c50 AC |
29103 | |
29104 | Reply: | |
29105 | @table @samp | |
b90a069a SL |
29106 | @item QC @var{thread-id} |
29107 | Where @var{thread-id} is a thread ID as documented in | |
29108 | @ref{thread-id syntax}. | |
b8ff78ce | 29109 | @item @r{(anything else)} |
b90a069a | 29110 | Any other reply implies the old thread ID. |
ee2d5c50 AC |
29111 | @end table |
29112 | ||
b8ff78ce | 29113 | @item qCRC:@var{addr},@var{length} |
ff2587ec | 29114 | @cindex CRC of memory block, remote request |
b8ff78ce | 29115 | @cindex @samp{qCRC} packet |
99e008fe EZ |
29116 | Compute the CRC checksum of a block of memory using CRC-32 defined in |
29117 | IEEE 802.3. The CRC is computed byte at a time, taking the most | |
29118 | significant bit of each byte first. The initial pattern code | |
29119 | @code{0xffffffff} is used to ensure leading zeros affect the CRC. | |
29120 | ||
29121 | @emph{Note:} This is the same CRC used in validating separate debug | |
29122 | files (@pxref{Separate Debug Files, , Debugging Information in Separate | |
29123 | Files}). However the algorithm is slightly different. When validating | |
29124 | separate debug files, the CRC is computed taking the @emph{least} | |
29125 | significant bit of each byte first, and the final result is inverted to | |
29126 | detect trailing zeros. | |
29127 | ||
ff2587ec WZ |
29128 | Reply: |
29129 | @table @samp | |
b8ff78ce | 29130 | @item E @var{NN} |
ff2587ec | 29131 | An error (such as memory fault) |
b8ff78ce JB |
29132 | @item C @var{crc32} |
29133 | The specified memory region's checksum is @var{crc32}. | |
ff2587ec WZ |
29134 | @end table |
29135 | ||
b8ff78ce JB |
29136 | @item qfThreadInfo |
29137 | @itemx qsThreadInfo | |
9c16f35a | 29138 | @cindex list active threads, remote request |
b8ff78ce JB |
29139 | @cindex @samp{qfThreadInfo} packet |
29140 | @cindex @samp{qsThreadInfo} packet | |
b90a069a | 29141 | Obtain a list of all active thread IDs from the target (OS). Since there |
8e04817f AC |
29142 | may be too many active threads to fit into one reply packet, this query |
29143 | works iteratively: it may require more than one query/reply sequence to | |
29144 | obtain the entire list of threads. The first query of the sequence will | |
b8ff78ce JB |
29145 | be the @samp{qfThreadInfo} query; subsequent queries in the |
29146 | sequence will be the @samp{qsThreadInfo} query. | |
ee2d5c50 | 29147 | |
b8ff78ce | 29148 | NOTE: This packet replaces the @samp{qL} query (see below). |
ee2d5c50 AC |
29149 | |
29150 | Reply: | |
29151 | @table @samp | |
b90a069a SL |
29152 | @item m @var{thread-id} |
29153 | A single thread ID | |
29154 | @item m @var{thread-id},@var{thread-id}@dots{} | |
29155 | a comma-separated list of thread IDs | |
b8ff78ce JB |
29156 | @item l |
29157 | (lower case letter @samp{L}) denotes end of list. | |
ee2d5c50 AC |
29158 | @end table |
29159 | ||
29160 | In response to each query, the target will reply with a list of one or | |
b90a069a | 29161 | more thread IDs, separated by commas. |
e1aac25b | 29162 | @value{GDBN} will respond to each reply with a request for more thread |
b8ff78ce | 29163 | ids (using the @samp{qs} form of the query), until the target responds |
b90a069a SL |
29164 | with @samp{l} (lower-case el, for @dfn{last}). |
29165 | Refer to @ref{thread-id syntax}, for the format of the @var{thread-id} | |
29166 | fields. | |
c906108c | 29167 | |
b8ff78ce | 29168 | @item qGetTLSAddr:@var{thread-id},@var{offset},@var{lm} |
ff2587ec | 29169 | @cindex get thread-local storage address, remote request |
b8ff78ce | 29170 | @cindex @samp{qGetTLSAddr} packet |
ff2587ec WZ |
29171 | Fetch the address associated with thread local storage specified |
29172 | by @var{thread-id}, @var{offset}, and @var{lm}. | |
29173 | ||
b90a069a SL |
29174 | @var{thread-id} is the thread ID associated with the |
29175 | thread for which to fetch the TLS address. @xref{thread-id syntax}. | |
ff2587ec WZ |
29176 | |
29177 | @var{offset} is the (big endian, hex encoded) offset associated with the | |
29178 | thread local variable. (This offset is obtained from the debug | |
29179 | information associated with the variable.) | |
29180 | ||
db2e3e2e | 29181 | @var{lm} is the (big endian, hex encoded) OS/ABI-specific encoding of the |
ff2587ec WZ |
29182 | the load module associated with the thread local storage. For example, |
29183 | a @sc{gnu}/Linux system will pass the link map address of the shared | |
29184 | object associated with the thread local storage under consideration. | |
29185 | Other operating environments may choose to represent the load module | |
29186 | differently, so the precise meaning of this parameter will vary. | |
ee2d5c50 AC |
29187 | |
29188 | Reply: | |
b8ff78ce JB |
29189 | @table @samp |
29190 | @item @var{XX}@dots{} | |
ff2587ec WZ |
29191 | Hex encoded (big endian) bytes representing the address of the thread |
29192 | local storage requested. | |
29193 | ||
b8ff78ce JB |
29194 | @item E @var{nn} |
29195 | An error occurred. @var{nn} are hex digits. | |
ff2587ec | 29196 | |
b8ff78ce JB |
29197 | @item |
29198 | An empty reply indicates that @samp{qGetTLSAddr} is not supported by the stub. | |
ee2d5c50 AC |
29199 | @end table |
29200 | ||
b8ff78ce | 29201 | @item qL @var{startflag} @var{threadcount} @var{nextthread} |
8e04817f AC |
29202 | Obtain thread information from RTOS. Where: @var{startflag} (one hex |
29203 | digit) is one to indicate the first query and zero to indicate a | |
29204 | subsequent query; @var{threadcount} (two hex digits) is the maximum | |
29205 | number of threads the response packet can contain; and @var{nextthread} | |
29206 | (eight hex digits), for subsequent queries (@var{startflag} is zero), is | |
29207 | returned in the response as @var{argthread}. | |
ee2d5c50 | 29208 | |
b8ff78ce | 29209 | Don't use this packet; use the @samp{qfThreadInfo} query instead (see above). |
ee2d5c50 AC |
29210 | |
29211 | Reply: | |
29212 | @table @samp | |
b8ff78ce | 29213 | @item qM @var{count} @var{done} @var{argthread} @var{thread}@dots{} |
8e04817f AC |
29214 | Where: @var{count} (two hex digits) is the number of threads being |
29215 | returned; @var{done} (one hex digit) is zero to indicate more threads | |
29216 | and one indicates no further threads; @var{argthreadid} (eight hex | |
b8ff78ce | 29217 | digits) is @var{nextthread} from the request packet; @var{thread}@dots{} |
ee2d5c50 | 29218 | is a sequence of thread IDs from the target. @var{threadid} (eight hex |
8e04817f | 29219 | digits). See @code{remote.c:parse_threadlist_response()}. |
ee2d5c50 | 29220 | @end table |
c906108c | 29221 | |
b8ff78ce | 29222 | @item qOffsets |
9c16f35a | 29223 | @cindex section offsets, remote request |
b8ff78ce | 29224 | @cindex @samp{qOffsets} packet |
31d99776 DJ |
29225 | Get section offsets that the target used when relocating the downloaded |
29226 | image. | |
c906108c | 29227 | |
ee2d5c50 AC |
29228 | Reply: |
29229 | @table @samp | |
31d99776 DJ |
29230 | @item Text=@var{xxx};Data=@var{yyy}@r{[};Bss=@var{zzz}@r{]} |
29231 | Relocate the @code{Text} section by @var{xxx} from its original address. | |
29232 | Relocate the @code{Data} section by @var{yyy} from its original address. | |
29233 | If the object file format provides segment information (e.g.@: @sc{elf} | |
29234 | @samp{PT_LOAD} program headers), @value{GDBN} will relocate entire | |
29235 | segments by the supplied offsets. | |
29236 | ||
29237 | @emph{Note: while a @code{Bss} offset may be included in the response, | |
29238 | @value{GDBN} ignores this and instead applies the @code{Data} offset | |
29239 | to the @code{Bss} section.} | |
29240 | ||
29241 | @item TextSeg=@var{xxx}@r{[};DataSeg=@var{yyy}@r{]} | |
29242 | Relocate the first segment of the object file, which conventionally | |
29243 | contains program code, to a starting address of @var{xxx}. If | |
29244 | @samp{DataSeg} is specified, relocate the second segment, which | |
29245 | conventionally contains modifiable data, to a starting address of | |
29246 | @var{yyy}. @value{GDBN} will report an error if the object file | |
29247 | does not contain segment information, or does not contain at least | |
29248 | as many segments as mentioned in the reply. Extra segments are | |
29249 | kept at fixed offsets relative to the last relocated segment. | |
ee2d5c50 AC |
29250 | @end table |
29251 | ||
b90a069a | 29252 | @item qP @var{mode} @var{thread-id} |
9c16f35a | 29253 | @cindex thread information, remote request |
b8ff78ce | 29254 | @cindex @samp{qP} packet |
b90a069a SL |
29255 | Returns information on @var{thread-id}. Where: @var{mode} is a hex |
29256 | encoded 32 bit mode; @var{thread-id} is a thread ID | |
29257 | (@pxref{thread-id syntax}). | |
ee2d5c50 | 29258 | |
aa56d27a JB |
29259 | Don't use this packet; use the @samp{qThreadExtraInfo} query instead |
29260 | (see below). | |
29261 | ||
b8ff78ce | 29262 | Reply: see @code{remote.c:remote_unpack_thread_info_response()}. |
c906108c | 29263 | |
8b23ecc4 SL |
29264 | @item QNonStop:1 |
29265 | @item QNonStop:0 | |
29266 | @cindex non-stop mode, remote request | |
29267 | @cindex @samp{QNonStop} packet | |
29268 | @anchor{QNonStop} | |
29269 | Enter non-stop (@samp{QNonStop:1}) or all-stop (@samp{QNonStop:0}) mode. | |
29270 | @xref{Remote Non-Stop}, for more information. | |
29271 | ||
29272 | Reply: | |
29273 | @table @samp | |
29274 | @item OK | |
29275 | The request succeeded. | |
29276 | ||
29277 | @item E @var{nn} | |
29278 | An error occurred. @var{nn} are hex digits. | |
29279 | ||
29280 | @item | |
29281 | An empty reply indicates that @samp{QNonStop} is not supported by | |
29282 | the stub. | |
29283 | @end table | |
29284 | ||
29285 | This packet is not probed by default; the remote stub must request it, | |
29286 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29287 | Use of this packet is controlled by the @code{set non-stop} command; | |
29288 | @pxref{Non-Stop Mode}. | |
29289 | ||
89be2091 DJ |
29290 | @item QPassSignals: @var{signal} @r{[};@var{signal}@r{]}@dots{} |
29291 | @cindex pass signals to inferior, remote request | |
29292 | @cindex @samp{QPassSignals} packet | |
23181151 | 29293 | @anchor{QPassSignals} |
89be2091 DJ |
29294 | Each listed @var{signal} should be passed directly to the inferior process. |
29295 | Signals are numbered identically to continue packets and stop replies | |
29296 | (@pxref{Stop Reply Packets}). Each @var{signal} list item should be | |
29297 | strictly greater than the previous item. These signals do not need to stop | |
29298 | the inferior, or be reported to @value{GDBN}. All other signals should be | |
29299 | reported to @value{GDBN}. Multiple @samp{QPassSignals} packets do not | |
29300 | combine; any earlier @samp{QPassSignals} list is completely replaced by the | |
29301 | new list. This packet improves performance when using @samp{handle | |
29302 | @var{signal} nostop noprint pass}. | |
29303 | ||
29304 | Reply: | |
29305 | @table @samp | |
29306 | @item OK | |
29307 | The request succeeded. | |
29308 | ||
29309 | @item E @var{nn} | |
29310 | An error occurred. @var{nn} are hex digits. | |
29311 | ||
29312 | @item | |
29313 | An empty reply indicates that @samp{QPassSignals} is not supported by | |
29314 | the stub. | |
29315 | @end table | |
29316 | ||
29317 | Use of this packet is controlled by the @code{set remote pass-signals} | |
79a6e687 | 29318 | command (@pxref{Remote Configuration, set remote pass-signals}). |
89be2091 DJ |
29319 | This packet is not probed by default; the remote stub must request it, |
29320 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29321 | ||
b8ff78ce | 29322 | @item qRcmd,@var{command} |
ff2587ec | 29323 | @cindex execute remote command, remote request |
b8ff78ce | 29324 | @cindex @samp{qRcmd} packet |
ff2587ec | 29325 | @var{command} (hex encoded) is passed to the local interpreter for |
b8ff78ce JB |
29326 | execution. Invalid commands should be reported using the output |
29327 | string. Before the final result packet, the target may also respond | |
29328 | with a number of intermediate @samp{O@var{output}} console output | |
29329 | packets. @emph{Implementors should note that providing access to a | |
29330 | stubs's interpreter may have security implications}. | |
fa93a9d8 | 29331 | |
ff2587ec WZ |
29332 | Reply: |
29333 | @table @samp | |
29334 | @item OK | |
29335 | A command response with no output. | |
29336 | @item @var{OUTPUT} | |
29337 | A command response with the hex encoded output string @var{OUTPUT}. | |
b8ff78ce | 29338 | @item E @var{NN} |
ff2587ec | 29339 | Indicate a badly formed request. |
b8ff78ce JB |
29340 | @item |
29341 | An empty reply indicates that @samp{qRcmd} is not recognized. | |
ff2587ec | 29342 | @end table |
fa93a9d8 | 29343 | |
aa56d27a JB |
29344 | (Note that the @code{qRcmd} packet's name is separated from the |
29345 | command by a @samp{,}, not a @samp{:}, contrary to the naming | |
29346 | conventions above. Please don't use this packet as a model for new | |
29347 | packets.) | |
29348 | ||
08388c79 DE |
29349 | @item qSearch:memory:@var{address};@var{length};@var{search-pattern} |
29350 | @cindex searching memory, in remote debugging | |
29351 | @cindex @samp{qSearch:memory} packet | |
29352 | @anchor{qSearch memory} | |
29353 | Search @var{length} bytes at @var{address} for @var{search-pattern}. | |
29354 | @var{address} and @var{length} are encoded in hex. | |
29355 | @var{search-pattern} is a sequence of bytes, hex encoded. | |
29356 | ||
29357 | Reply: | |
29358 | @table @samp | |
29359 | @item 0 | |
29360 | The pattern was not found. | |
29361 | @item 1,address | |
29362 | The pattern was found at @var{address}. | |
29363 | @item E @var{NN} | |
29364 | A badly formed request or an error was encountered while searching memory. | |
29365 | @item | |
29366 | An empty reply indicates that @samp{qSearch:memory} is not recognized. | |
29367 | @end table | |
29368 | ||
a6f3e723 SL |
29369 | @item QStartNoAckMode |
29370 | @cindex @samp{QStartNoAckMode} packet | |
29371 | @anchor{QStartNoAckMode} | |
29372 | Request that the remote stub disable the normal @samp{+}/@samp{-} | |
29373 | protocol acknowledgments (@pxref{Packet Acknowledgment}). | |
29374 | ||
29375 | Reply: | |
29376 | @table @samp | |
29377 | @item OK | |
29378 | The stub has switched to no-acknowledgment mode. | |
29379 | @value{GDBN} acknowledges this reponse, | |
29380 | but neither the stub nor @value{GDBN} shall send or expect further | |
29381 | @samp{+}/@samp{-} acknowledgments in the current connection. | |
29382 | @item | |
29383 | An empty reply indicates that the stub does not support no-acknowledgment mode. | |
29384 | @end table | |
29385 | ||
be2a5f71 DJ |
29386 | @item qSupported @r{[}:@var{gdbfeature} @r{[};@var{gdbfeature}@r{]}@dots{} @r{]} |
29387 | @cindex supported packets, remote query | |
29388 | @cindex features of the remote protocol | |
29389 | @cindex @samp{qSupported} packet | |
0876f84a | 29390 | @anchor{qSupported} |
be2a5f71 DJ |
29391 | Tell the remote stub about features supported by @value{GDBN}, and |
29392 | query the stub for features it supports. This packet allows | |
29393 | @value{GDBN} and the remote stub to take advantage of each others' | |
29394 | features. @samp{qSupported} also consolidates multiple feature probes | |
29395 | at startup, to improve @value{GDBN} performance---a single larger | |
29396 | packet performs better than multiple smaller probe packets on | |
29397 | high-latency links. Some features may enable behavior which must not | |
29398 | be on by default, e.g.@: because it would confuse older clients or | |
29399 | stubs. Other features may describe packets which could be | |
29400 | automatically probed for, but are not. These features must be | |
29401 | reported before @value{GDBN} will use them. This ``default | |
29402 | unsupported'' behavior is not appropriate for all packets, but it | |
29403 | helps to keep the initial connection time under control with new | |
29404 | versions of @value{GDBN} which support increasing numbers of packets. | |
29405 | ||
29406 | Reply: | |
29407 | @table @samp | |
29408 | @item @var{stubfeature} @r{[};@var{stubfeature}@r{]}@dots{} | |
29409 | The stub supports or does not support each returned @var{stubfeature}, | |
29410 | depending on the form of each @var{stubfeature} (see below for the | |
29411 | possible forms). | |
29412 | @item | |
29413 | An empty reply indicates that @samp{qSupported} is not recognized, | |
29414 | or that no features needed to be reported to @value{GDBN}. | |
29415 | @end table | |
29416 | ||
29417 | The allowed forms for each feature (either a @var{gdbfeature} in the | |
29418 | @samp{qSupported} packet, or a @var{stubfeature} in the response) | |
29419 | are: | |
29420 | ||
29421 | @table @samp | |
29422 | @item @var{name}=@var{value} | |
29423 | The remote protocol feature @var{name} is supported, and associated | |
29424 | with the specified @var{value}. The format of @var{value} depends | |
29425 | on the feature, but it must not include a semicolon. | |
29426 | @item @var{name}+ | |
29427 | The remote protocol feature @var{name} is supported, and does not | |
29428 | need an associated value. | |
29429 | @item @var{name}- | |
29430 | The remote protocol feature @var{name} is not supported. | |
29431 | @item @var{name}? | |
29432 | The remote protocol feature @var{name} may be supported, and | |
29433 | @value{GDBN} should auto-detect support in some other way when it is | |
29434 | needed. This form will not be used for @var{gdbfeature} notifications, | |
29435 | but may be used for @var{stubfeature} responses. | |
29436 | @end table | |
29437 | ||
29438 | Whenever the stub receives a @samp{qSupported} request, the | |
29439 | supplied set of @value{GDBN} features should override any previous | |
29440 | request. This allows @value{GDBN} to put the stub in a known | |
29441 | state, even if the stub had previously been communicating with | |
29442 | a different version of @value{GDBN}. | |
29443 | ||
b90a069a SL |
29444 | The following values of @var{gdbfeature} (for the packet sent by @value{GDBN}) |
29445 | are defined: | |
29446 | ||
29447 | @table @samp | |
29448 | @item multiprocess | |
29449 | This feature indicates whether @value{GDBN} supports multiprocess | |
29450 | extensions to the remote protocol. @value{GDBN} does not use such | |
29451 | extensions unless the stub also reports that it supports them by | |
29452 | including @samp{multiprocess+} in its @samp{qSupported} reply. | |
29453 | @xref{multiprocess extensions}, for details. | |
29454 | @end table | |
29455 | ||
29456 | Stubs should ignore any unknown values for | |
be2a5f71 DJ |
29457 | @var{gdbfeature}. Any @value{GDBN} which sends a @samp{qSupported} |
29458 | packet supports receiving packets of unlimited length (earlier | |
b90a069a | 29459 | versions of @value{GDBN} may reject overly long responses). Additional values |
be2a5f71 DJ |
29460 | for @var{gdbfeature} may be defined in the future to let the stub take |
29461 | advantage of new features in @value{GDBN}, e.g.@: incompatible | |
b90a069a SL |
29462 | improvements in the remote protocol---the @samp{multiprocess} feature is |
29463 | an example of such a feature. The stub's reply should be independent | |
be2a5f71 DJ |
29464 | of the @var{gdbfeature} entries sent by @value{GDBN}; first @value{GDBN} |
29465 | describes all the features it supports, and then the stub replies with | |
29466 | all the features it supports. | |
29467 | ||
29468 | Similarly, @value{GDBN} will silently ignore unrecognized stub feature | |
29469 | responses, as long as each response uses one of the standard forms. | |
29470 | ||
29471 | Some features are flags. A stub which supports a flag feature | |
29472 | should respond with a @samp{+} form response. Other features | |
29473 | require values, and the stub should respond with an @samp{=} | |
29474 | form response. | |
29475 | ||
29476 | Each feature has a default value, which @value{GDBN} will use if | |
29477 | @samp{qSupported} is not available or if the feature is not mentioned | |
29478 | in the @samp{qSupported} response. The default values are fixed; a | |
29479 | stub is free to omit any feature responses that match the defaults. | |
29480 | ||
29481 | Not all features can be probed, but for those which can, the probing | |
29482 | mechanism is useful: in some cases, a stub's internal | |
29483 | architecture may not allow the protocol layer to know some information | |
29484 | about the underlying target in advance. This is especially common in | |
29485 | stubs which may be configured for multiple targets. | |
29486 | ||
29487 | These are the currently defined stub features and their properties: | |
29488 | ||
cfa9d6d9 | 29489 | @multitable @columnfractions 0.35 0.2 0.12 0.2 |
be2a5f71 DJ |
29490 | @c NOTE: The first row should be @headitem, but we do not yet require |
29491 | @c a new enough version of Texinfo (4.7) to use @headitem. | |
0876f84a | 29492 | @item Feature Name |
be2a5f71 DJ |
29493 | @tab Value Required |
29494 | @tab Default | |
29495 | @tab Probe Allowed | |
29496 | ||
29497 | @item @samp{PacketSize} | |
29498 | @tab Yes | |
29499 | @tab @samp{-} | |
29500 | @tab No | |
29501 | ||
0876f84a DJ |
29502 | @item @samp{qXfer:auxv:read} |
29503 | @tab No | |
29504 | @tab @samp{-} | |
29505 | @tab Yes | |
29506 | ||
23181151 DJ |
29507 | @item @samp{qXfer:features:read} |
29508 | @tab No | |
29509 | @tab @samp{-} | |
29510 | @tab Yes | |
29511 | ||
cfa9d6d9 DJ |
29512 | @item @samp{qXfer:libraries:read} |
29513 | @tab No | |
29514 | @tab @samp{-} | |
29515 | @tab Yes | |
29516 | ||
68437a39 DJ |
29517 | @item @samp{qXfer:memory-map:read} |
29518 | @tab No | |
29519 | @tab @samp{-} | |
29520 | @tab Yes | |
29521 | ||
0e7f50da UW |
29522 | @item @samp{qXfer:spu:read} |
29523 | @tab No | |
29524 | @tab @samp{-} | |
29525 | @tab Yes | |
29526 | ||
29527 | @item @samp{qXfer:spu:write} | |
29528 | @tab No | |
29529 | @tab @samp{-} | |
29530 | @tab Yes | |
29531 | ||
4aa995e1 PA |
29532 | @item @samp{qXfer:siginfo:read} |
29533 | @tab No | |
29534 | @tab @samp{-} | |
29535 | @tab Yes | |
29536 | ||
29537 | @item @samp{qXfer:siginfo:write} | |
29538 | @tab No | |
29539 | @tab @samp{-} | |
29540 | @tab Yes | |
29541 | ||
8b23ecc4 SL |
29542 | @item @samp{QNonStop} |
29543 | @tab No | |
29544 | @tab @samp{-} | |
29545 | @tab Yes | |
29546 | ||
89be2091 DJ |
29547 | @item @samp{QPassSignals} |
29548 | @tab No | |
29549 | @tab @samp{-} | |
29550 | @tab Yes | |
29551 | ||
a6f3e723 SL |
29552 | @item @samp{QStartNoAckMode} |
29553 | @tab No | |
29554 | @tab @samp{-} | |
29555 | @tab Yes | |
29556 | ||
b90a069a SL |
29557 | @item @samp{multiprocess} |
29558 | @tab No | |
29559 | @tab @samp{-} | |
29560 | @tab No | |
29561 | ||
782b2b07 SS |
29562 | @item @samp{ConditionalTracepoints} |
29563 | @tab No | |
29564 | @tab @samp{-} | |
29565 | @tab No | |
29566 | ||
0d772ac9 MS |
29567 | @item @samp{ReverseContinue} |
29568 | @tab No | |
2f8132f3 | 29569 | @tab @samp{-} |
0d772ac9 MS |
29570 | @tab No |
29571 | ||
29572 | @item @samp{ReverseStep} | |
29573 | @tab No | |
2f8132f3 | 29574 | @tab @samp{-} |
0d772ac9 MS |
29575 | @tab No |
29576 | ||
be2a5f71 DJ |
29577 | @end multitable |
29578 | ||
29579 | These are the currently defined stub features, in more detail: | |
29580 | ||
29581 | @table @samp | |
29582 | @cindex packet size, remote protocol | |
29583 | @item PacketSize=@var{bytes} | |
29584 | The remote stub can accept packets up to at least @var{bytes} in | |
29585 | length. @value{GDBN} will send packets up to this size for bulk | |
29586 | transfers, and will never send larger packets. This is a limit on the | |
29587 | data characters in the packet, including the frame and checksum. | |
29588 | There is no trailing NUL byte in a remote protocol packet; if the stub | |
29589 | stores packets in a NUL-terminated format, it should allow an extra | |
29590 | byte in its buffer for the NUL. If this stub feature is not supported, | |
29591 | @value{GDBN} guesses based on the size of the @samp{g} packet response. | |
29592 | ||
0876f84a DJ |
29593 | @item qXfer:auxv:read |
29594 | The remote stub understands the @samp{qXfer:auxv:read} packet | |
29595 | (@pxref{qXfer auxiliary vector read}). | |
29596 | ||
23181151 DJ |
29597 | @item qXfer:features:read |
29598 | The remote stub understands the @samp{qXfer:features:read} packet | |
29599 | (@pxref{qXfer target description read}). | |
29600 | ||
cfa9d6d9 DJ |
29601 | @item qXfer:libraries:read |
29602 | The remote stub understands the @samp{qXfer:libraries:read} packet | |
29603 | (@pxref{qXfer library list read}). | |
29604 | ||
23181151 DJ |
29605 | @item qXfer:memory-map:read |
29606 | The remote stub understands the @samp{qXfer:memory-map:read} packet | |
29607 | (@pxref{qXfer memory map read}). | |
29608 | ||
0e7f50da UW |
29609 | @item qXfer:spu:read |
29610 | The remote stub understands the @samp{qXfer:spu:read} packet | |
29611 | (@pxref{qXfer spu read}). | |
29612 | ||
29613 | @item qXfer:spu:write | |
29614 | The remote stub understands the @samp{qXfer:spu:write} packet | |
29615 | (@pxref{qXfer spu write}). | |
29616 | ||
4aa995e1 PA |
29617 | @item qXfer:siginfo:read |
29618 | The remote stub understands the @samp{qXfer:siginfo:read} packet | |
29619 | (@pxref{qXfer siginfo read}). | |
29620 | ||
29621 | @item qXfer:siginfo:write | |
29622 | The remote stub understands the @samp{qXfer:siginfo:write} packet | |
29623 | (@pxref{qXfer siginfo write}). | |
29624 | ||
8b23ecc4 SL |
29625 | @item QNonStop |
29626 | The remote stub understands the @samp{QNonStop} packet | |
29627 | (@pxref{QNonStop}). | |
29628 | ||
23181151 DJ |
29629 | @item QPassSignals |
29630 | The remote stub understands the @samp{QPassSignals} packet | |
29631 | (@pxref{QPassSignals}). | |
29632 | ||
a6f3e723 SL |
29633 | @item QStartNoAckMode |
29634 | The remote stub understands the @samp{QStartNoAckMode} packet and | |
29635 | prefers to operate in no-acknowledgment mode. @xref{Packet Acknowledgment}. | |
29636 | ||
b90a069a SL |
29637 | @item multiprocess |
29638 | @anchor{multiprocess extensions} | |
29639 | @cindex multiprocess extensions, in remote protocol | |
29640 | The remote stub understands the multiprocess extensions to the remote | |
29641 | protocol syntax. The multiprocess extensions affect the syntax of | |
29642 | thread IDs in both packets and replies (@pxref{thread-id syntax}), and | |
29643 | add process IDs to the @samp{D} packet and @samp{W} and @samp{X} | |
29644 | replies. Note that reporting this feature indicates support for the | |
29645 | syntactic extensions only, not that the stub necessarily supports | |
29646 | debugging of more than one process at a time. The stub must not use | |
29647 | multiprocess extensions in packet replies unless @value{GDBN} has also | |
29648 | indicated it supports them in its @samp{qSupported} request. | |
29649 | ||
07e059b5 VP |
29650 | @item qXfer:osdata:read |
29651 | The remote stub understands the @samp{qXfer:osdata:read} packet | |
29652 | ((@pxref{qXfer osdata read}). | |
29653 | ||
782b2b07 SS |
29654 | @item ConditionalTracepoints |
29655 | The remote stub accepts and implements conditional expressions defined | |
29656 | for tracepoints (@pxref{Tracepoint Conditions}). | |
29657 | ||
0d772ac9 MS |
29658 | @item ReverseContinue |
29659 | The remote stub accepts and implements the reverse continue packet | |
29660 | (@pxref{bc}). | |
29661 | ||
29662 | @item ReverseStep | |
29663 | The remote stub accepts and implements the reverse step packet | |
29664 | (@pxref{bs}). | |
29665 | ||
be2a5f71 DJ |
29666 | @end table |
29667 | ||
b8ff78ce | 29668 | @item qSymbol:: |
ff2587ec | 29669 | @cindex symbol lookup, remote request |
b8ff78ce | 29670 | @cindex @samp{qSymbol} packet |
ff2587ec WZ |
29671 | Notify the target that @value{GDBN} is prepared to serve symbol lookup |
29672 | requests. Accept requests from the target for the values of symbols. | |
fa93a9d8 JB |
29673 | |
29674 | Reply: | |
ff2587ec | 29675 | @table @samp |
b8ff78ce | 29676 | @item OK |
ff2587ec | 29677 | The target does not need to look up any (more) symbols. |
b8ff78ce | 29678 | @item qSymbol:@var{sym_name} |
ff2587ec WZ |
29679 | The target requests the value of symbol @var{sym_name} (hex encoded). |
29680 | @value{GDBN} may provide the value by using the | |
b8ff78ce JB |
29681 | @samp{qSymbol:@var{sym_value}:@var{sym_name}} message, described |
29682 | below. | |
ff2587ec | 29683 | @end table |
83761cbd | 29684 | |
b8ff78ce | 29685 | @item qSymbol:@var{sym_value}:@var{sym_name} |
ff2587ec WZ |
29686 | Set the value of @var{sym_name} to @var{sym_value}. |
29687 | ||
29688 | @var{sym_name} (hex encoded) is the name of a symbol whose value the | |
29689 | target has previously requested. | |
29690 | ||
29691 | @var{sym_value} (hex) is the value for symbol @var{sym_name}. If | |
29692 | @value{GDBN} cannot supply a value for @var{sym_name}, then this field | |
29693 | will be empty. | |
29694 | ||
29695 | Reply: | |
29696 | @table @samp | |
b8ff78ce | 29697 | @item OK |
ff2587ec | 29698 | The target does not need to look up any (more) symbols. |
b8ff78ce | 29699 | @item qSymbol:@var{sym_name} |
ff2587ec WZ |
29700 | The target requests the value of a new symbol @var{sym_name} (hex |
29701 | encoded). @value{GDBN} will continue to supply the values of symbols | |
29702 | (if available), until the target ceases to request them. | |
fa93a9d8 | 29703 | @end table |
0abb7bc7 | 29704 | |
9d29849a JB |
29705 | @item QTDP |
29706 | @itemx QTFrame | |
29707 | @xref{Tracepoint Packets}. | |
29708 | ||
b90a069a | 29709 | @item qThreadExtraInfo,@var{thread-id} |
ff2587ec | 29710 | @cindex thread attributes info, remote request |
b8ff78ce JB |
29711 | @cindex @samp{qThreadExtraInfo} packet |
29712 | Obtain a printable string description of a thread's attributes from | |
b90a069a SL |
29713 | the target OS. @var{thread-id} is a thread ID; |
29714 | see @ref{thread-id syntax}. This | |
b8ff78ce JB |
29715 | string may contain anything that the target OS thinks is interesting |
29716 | for @value{GDBN} to tell the user about the thread. The string is | |
29717 | displayed in @value{GDBN}'s @code{info threads} display. Some | |
29718 | examples of possible thread extra info strings are @samp{Runnable}, or | |
29719 | @samp{Blocked on Mutex}. | |
ff2587ec WZ |
29720 | |
29721 | Reply: | |
29722 | @table @samp | |
b8ff78ce JB |
29723 | @item @var{XX}@dots{} |
29724 | Where @samp{@var{XX}@dots{}} is a hex encoding of @sc{ascii} data, | |
29725 | comprising the printable string containing the extra information about | |
29726 | the thread's attributes. | |
ff2587ec | 29727 | @end table |
814e32d7 | 29728 | |
aa56d27a JB |
29729 | (Note that the @code{qThreadExtraInfo} packet's name is separated from |
29730 | the command by a @samp{,}, not a @samp{:}, contrary to the naming | |
29731 | conventions above. Please don't use this packet as a model for new | |
29732 | packets.) | |
29733 | ||
9d29849a JB |
29734 | @item QTStart |
29735 | @itemx QTStop | |
29736 | @itemx QTinit | |
29737 | @itemx QTro | |
29738 | @itemx qTStatus | |
29739 | @xref{Tracepoint Packets}. | |
29740 | ||
0876f84a DJ |
29741 | @item qXfer:@var{object}:read:@var{annex}:@var{offset},@var{length} |
29742 | @cindex read special object, remote request | |
29743 | @cindex @samp{qXfer} packet | |
68437a39 | 29744 | @anchor{qXfer read} |
0876f84a DJ |
29745 | Read uninterpreted bytes from the target's special data area |
29746 | identified by the keyword @var{object}. Request @var{length} bytes | |
29747 | starting at @var{offset} bytes into the data. The content and | |
0e7f50da | 29748 | encoding of @var{annex} is specific to @var{object}; it can supply |
0876f84a DJ |
29749 | additional details about what data to access. |
29750 | ||
29751 | Here are the specific requests of this form defined so far. All | |
29752 | @samp{qXfer:@var{object}:read:@dots{}} requests use the same reply | |
29753 | formats, listed below. | |
29754 | ||
29755 | @table @samp | |
29756 | @item qXfer:auxv:read::@var{offset},@var{length} | |
29757 | @anchor{qXfer auxiliary vector read} | |
29758 | Access the target's @dfn{auxiliary vector}. @xref{OS Information, | |
427c3a89 | 29759 | auxiliary vector}. Note @var{annex} must be empty. |
0876f84a DJ |
29760 | |
29761 | This packet is not probed by default; the remote stub must request it, | |
89be2091 | 29762 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). |
0876f84a | 29763 | |
23181151 DJ |
29764 | @item qXfer:features:read:@var{annex}:@var{offset},@var{length} |
29765 | @anchor{qXfer target description read} | |
29766 | Access the @dfn{target description}. @xref{Target Descriptions}. The | |
29767 | annex specifies which XML document to access. The main description is | |
29768 | always loaded from the @samp{target.xml} annex. | |
29769 | ||
29770 | This packet is not probed by default; the remote stub must request it, | |
29771 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29772 | ||
cfa9d6d9 DJ |
29773 | @item qXfer:libraries:read:@var{annex}:@var{offset},@var{length} |
29774 | @anchor{qXfer library list read} | |
29775 | Access the target's list of loaded libraries. @xref{Library List Format}. | |
29776 | The annex part of the generic @samp{qXfer} packet must be empty | |
29777 | (@pxref{qXfer read}). | |
29778 | ||
29779 | Targets which maintain a list of libraries in the program's memory do | |
29780 | not need to implement this packet; it is designed for platforms where | |
29781 | the operating system manages the list of loaded libraries. | |
29782 | ||
29783 | This packet is not probed by default; the remote stub must request it, | |
29784 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29785 | ||
68437a39 DJ |
29786 | @item qXfer:memory-map:read::@var{offset},@var{length} |
29787 | @anchor{qXfer memory map read} | |
79a6e687 | 29788 | Access the target's @dfn{memory-map}. @xref{Memory Map Format}. The |
68437a39 DJ |
29789 | annex part of the generic @samp{qXfer} packet must be empty |
29790 | (@pxref{qXfer read}). | |
29791 | ||
0e7f50da UW |
29792 | This packet is not probed by default; the remote stub must request it, |
29793 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29794 | ||
4aa995e1 PA |
29795 | @item qXfer:siginfo:read::@var{offset},@var{length} |
29796 | @anchor{qXfer siginfo read} | |
29797 | Read contents of the extra signal information on the target | |
29798 | system. The annex part of the generic @samp{qXfer} packet must be | |
29799 | empty (@pxref{qXfer read}). | |
29800 | ||
29801 | This packet is not probed by default; the remote stub must request it, | |
29802 | by supplying an appropriate @samp{qSupported} response | |
29803 | (@pxref{qSupported}). | |
29804 | ||
0e7f50da UW |
29805 | @item qXfer:spu:read:@var{annex}:@var{offset},@var{length} |
29806 | @anchor{qXfer spu read} | |
29807 | Read contents of an @code{spufs} file on the target system. The | |
29808 | annex specifies which file to read; it must be of the form | |
29809 | @file{@var{id}/@var{name}}, where @var{id} specifies an SPU context ID | |
29810 | in the target process, and @var{name} identifes the @code{spufs} file | |
29811 | in that context to be accessed. | |
29812 | ||
68437a39 | 29813 | This packet is not probed by default; the remote stub must request it, |
07e059b5 VP |
29814 | by supplying an appropriate @samp{qSupported} response |
29815 | (@pxref{qSupported}). | |
29816 | ||
29817 | @item qXfer:osdata:read::@var{offset},@var{length} | |
29818 | @anchor{qXfer osdata read} | |
29819 | Access the target's @dfn{operating system information}. | |
29820 | @xref{Operating System Information}. | |
29821 | ||
68437a39 DJ |
29822 | @end table |
29823 | ||
0876f84a DJ |
29824 | Reply: |
29825 | @table @samp | |
29826 | @item m @var{data} | |
29827 | Data @var{data} (@pxref{Binary Data}) has been read from the | |
29828 | target. There may be more data at a higher address (although | |
29829 | it is permitted to return @samp{m} even for the last valid | |
29830 | block of data, as long as at least one byte of data was read). | |
29831 | @var{data} may have fewer bytes than the @var{length} in the | |
29832 | request. | |
29833 | ||
29834 | @item l @var{data} | |
29835 | Data @var{data} (@pxref{Binary Data}) has been read from the target. | |
29836 | There is no more data to be read. @var{data} may have fewer bytes | |
29837 | than the @var{length} in the request. | |
29838 | ||
29839 | @item l | |
29840 | The @var{offset} in the request is at the end of the data. | |
29841 | There is no more data to be read. | |
29842 | ||
29843 | @item E00 | |
29844 | The request was malformed, or @var{annex} was invalid. | |
29845 | ||
29846 | @item E @var{nn} | |
29847 | The offset was invalid, or there was an error encountered reading the data. | |
29848 | @var{nn} is a hex-encoded @code{errno} value. | |
29849 | ||
29850 | @item | |
29851 | An empty reply indicates the @var{object} string was not recognized by | |
29852 | the stub, or that the object does not support reading. | |
29853 | @end table | |
29854 | ||
29855 | @item qXfer:@var{object}:write:@var{annex}:@var{offset}:@var{data}@dots{} | |
29856 | @cindex write data into object, remote request | |
4aa995e1 | 29857 | @anchor{qXfer write} |
0876f84a DJ |
29858 | Write uninterpreted bytes into the target's special data area |
29859 | identified by the keyword @var{object}, starting at @var{offset} bytes | |
0e7f50da | 29860 | into the data. @var{data}@dots{} is the binary-encoded data |
0876f84a | 29861 | (@pxref{Binary Data}) to be written. The content and encoding of @var{annex} |
0e7f50da | 29862 | is specific to @var{object}; it can supply additional details about what data |
0876f84a DJ |
29863 | to access. |
29864 | ||
0e7f50da UW |
29865 | Here are the specific requests of this form defined so far. All |
29866 | @samp{qXfer:@var{object}:write:@dots{}} requests use the same reply | |
29867 | formats, listed below. | |
29868 | ||
29869 | @table @samp | |
4aa995e1 PA |
29870 | @item qXfer:siginfo:write::@var{offset}:@var{data}@dots{} |
29871 | @anchor{qXfer siginfo write} | |
29872 | Write @var{data} to the extra signal information on the target system. | |
29873 | The annex part of the generic @samp{qXfer} packet must be | |
29874 | empty (@pxref{qXfer write}). | |
29875 | ||
29876 | This packet is not probed by default; the remote stub must request it, | |
29877 | by supplying an appropriate @samp{qSupported} response | |
29878 | (@pxref{qSupported}). | |
29879 | ||
84fcdf95 | 29880 | @item qXfer:spu:write:@var{annex}:@var{offset}:@var{data}@dots{} |
0e7f50da UW |
29881 | @anchor{qXfer spu write} |
29882 | Write @var{data} to an @code{spufs} file on the target system. The | |
29883 | annex specifies which file to write; it must be of the form | |
29884 | @file{@var{id}/@var{name}}, where @var{id} specifies an SPU context ID | |
29885 | in the target process, and @var{name} identifes the @code{spufs} file | |
29886 | in that context to be accessed. | |
29887 | ||
29888 | This packet is not probed by default; the remote stub must request it, | |
29889 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29890 | @end table | |
0876f84a DJ |
29891 | |
29892 | Reply: | |
29893 | @table @samp | |
29894 | @item @var{nn} | |
29895 | @var{nn} (hex encoded) is the number of bytes written. | |
29896 | This may be fewer bytes than supplied in the request. | |
29897 | ||
29898 | @item E00 | |
29899 | The request was malformed, or @var{annex} was invalid. | |
29900 | ||
29901 | @item E @var{nn} | |
29902 | The offset was invalid, or there was an error encountered writing the data. | |
29903 | @var{nn} is a hex-encoded @code{errno} value. | |
29904 | ||
29905 | @item | |
29906 | An empty reply indicates the @var{object} string was not | |
29907 | recognized by the stub, or that the object does not support writing. | |
29908 | @end table | |
29909 | ||
29910 | @item qXfer:@var{object}:@var{operation}:@dots{} | |
29911 | Requests of this form may be added in the future. When a stub does | |
29912 | not recognize the @var{object} keyword, or its support for | |
29913 | @var{object} does not recognize the @var{operation} keyword, the stub | |
29914 | must respond with an empty packet. | |
29915 | ||
0b16c5cf PA |
29916 | @item qAttached:@var{pid} |
29917 | @cindex query attached, remote request | |
29918 | @cindex @samp{qAttached} packet | |
29919 | Return an indication of whether the remote server attached to an | |
29920 | existing process or created a new process. When the multiprocess | |
29921 | protocol extensions are supported (@pxref{multiprocess extensions}), | |
29922 | @var{pid} is an integer in hexadecimal format identifying the target | |
29923 | process. Otherwise, @value{GDBN} will omit the @var{pid} field and | |
29924 | the query packet will be simplified as @samp{qAttached}. | |
29925 | ||
29926 | This query is used, for example, to know whether the remote process | |
29927 | should be detached or killed when a @value{GDBN} session is ended with | |
29928 | the @code{quit} command. | |
29929 | ||
29930 | Reply: | |
29931 | @table @samp | |
29932 | @item 1 | |
29933 | The remote server attached to an existing process. | |
29934 | @item 0 | |
29935 | The remote server created a new process. | |
29936 | @item E @var{NN} | |
29937 | A badly formed request or an error was encountered. | |
29938 | @end table | |
29939 | ||
ee2d5c50 AC |
29940 | @end table |
29941 | ||
29942 | @node Register Packet Format | |
29943 | @section Register Packet Format | |
eb12ee30 | 29944 | |
b8ff78ce | 29945 | The following @code{g}/@code{G} packets have previously been defined. |
ee2d5c50 AC |
29946 | In the below, some thirty-two bit registers are transferred as |
29947 | sixty-four bits. Those registers should be zero/sign extended (which?) | |
599b237a BW |
29948 | to fill the space allocated. Register bytes are transferred in target |
29949 | byte order. The two nibbles within a register byte are transferred | |
ee2d5c50 | 29950 | most-significant - least-significant. |
eb12ee30 | 29951 | |
ee2d5c50 | 29952 | @table @r |
eb12ee30 | 29953 | |
8e04817f | 29954 | @item MIPS32 |
ee2d5c50 | 29955 | |
599b237a | 29956 | All registers are transferred as thirty-two bit quantities in the order: |
8e04817f AC |
29957 | 32 general-purpose; sr; lo; hi; bad; cause; pc; 32 floating-point |
29958 | registers; fsr; fir; fp. | |
eb12ee30 | 29959 | |
8e04817f | 29960 | @item MIPS64 |
ee2d5c50 | 29961 | |
599b237a | 29962 | All registers are transferred as sixty-four bit quantities (including |
8e04817f AC |
29963 | thirty-two bit registers such as @code{sr}). The ordering is the same |
29964 | as @code{MIPS32}. | |
eb12ee30 | 29965 | |
ee2d5c50 AC |
29966 | @end table |
29967 | ||
9d29849a JB |
29968 | @node Tracepoint Packets |
29969 | @section Tracepoint Packets | |
29970 | @cindex tracepoint packets | |
29971 | @cindex packets, tracepoint | |
29972 | ||
29973 | Here we describe the packets @value{GDBN} uses to implement | |
29974 | tracepoints (@pxref{Tracepoints}). | |
29975 | ||
29976 | @table @samp | |
29977 | ||
782b2b07 | 29978 | @item QTDP:@var{n}:@var{addr}:@var{ena}:@var{step}:@var{pass}[:X@var{len},@var{bytes}]@r{[}-@r{]} |
9d29849a JB |
29979 | Create a new tracepoint, number @var{n}, at @var{addr}. If @var{ena} |
29980 | is @samp{E}, then the tracepoint is enabled; if it is @samp{D}, then | |
29981 | the tracepoint is disabled. @var{step} is the tracepoint's step | |
782b2b07 SS |
29982 | count, and @var{pass} is its pass count. If an @samp{X} is present, |
29983 | it introduces a tracepoint condition, which consists of a hexadecimal | |
29984 | length, followed by a comma and hex-encoded bytes, in a manner similar | |
29985 | to action encodings as described below. If the trailing @samp{-} is | |
9d29849a JB |
29986 | present, further @samp{QTDP} packets will follow to specify this |
29987 | tracepoint's actions. | |
29988 | ||
29989 | Replies: | |
29990 | @table @samp | |
29991 | @item OK | |
29992 | The packet was understood and carried out. | |
29993 | @item | |
29994 | The packet was not recognized. | |
29995 | @end table | |
29996 | ||
29997 | @item QTDP:-@var{n}:@var{addr}:@r{[}S@r{]}@var{action}@dots{}@r{[}-@r{]} | |
29998 | Define actions to be taken when a tracepoint is hit. @var{n} and | |
29999 | @var{addr} must be the same as in the initial @samp{QTDP} packet for | |
30000 | this tracepoint. This packet may only be sent immediately after | |
30001 | another @samp{QTDP} packet that ended with a @samp{-}. If the | |
30002 | trailing @samp{-} is present, further @samp{QTDP} packets will follow, | |
30003 | specifying more actions for this tracepoint. | |
30004 | ||
30005 | In the series of action packets for a given tracepoint, at most one | |
30006 | can have an @samp{S} before its first @var{action}. If such a packet | |
30007 | is sent, it and the following packets define ``while-stepping'' | |
30008 | actions. Any prior packets define ordinary actions --- that is, those | |
30009 | taken when the tracepoint is first hit. If no action packet has an | |
30010 | @samp{S}, then all the packets in the series specify ordinary | |
30011 | tracepoint actions. | |
30012 | ||
30013 | The @samp{@var{action}@dots{}} portion of the packet is a series of | |
30014 | actions, concatenated without separators. Each action has one of the | |
30015 | following forms: | |
30016 | ||
30017 | @table @samp | |
30018 | ||
30019 | @item R @var{mask} | |
30020 | Collect the registers whose bits are set in @var{mask}. @var{mask} is | |
599b237a | 30021 | a hexadecimal number whose @var{i}'th bit is set if register number |
9d29849a JB |
30022 | @var{i} should be collected. (The least significant bit is numbered |
30023 | zero.) Note that @var{mask} may be any number of digits long; it may | |
30024 | not fit in a 32-bit word. | |
30025 | ||
30026 | @item M @var{basereg},@var{offset},@var{len} | |
30027 | Collect @var{len} bytes of memory starting at the address in register | |
30028 | number @var{basereg}, plus @var{offset}. If @var{basereg} is | |
30029 | @samp{-1}, then the range has a fixed address: @var{offset} is the | |
30030 | address of the lowest byte to collect. The @var{basereg}, | |
599b237a | 30031 | @var{offset}, and @var{len} parameters are all unsigned hexadecimal |
9d29849a JB |
30032 | values (the @samp{-1} value for @var{basereg} is a special case). |
30033 | ||
30034 | @item X @var{len},@var{expr} | |
30035 | Evaluate @var{expr}, whose length is @var{len}, and collect memory as | |
30036 | it directs. @var{expr} is an agent expression, as described in | |
30037 | @ref{Agent Expressions}. Each byte of the expression is encoded as a | |
30038 | two-digit hex number in the packet; @var{len} is the number of bytes | |
30039 | in the expression (and thus one-half the number of hex digits in the | |
30040 | packet). | |
30041 | ||
30042 | @end table | |
30043 | ||
30044 | Any number of actions may be packed together in a single @samp{QTDP} | |
30045 | packet, as long as the packet does not exceed the maximum packet | |
c1947b85 JB |
30046 | length (400 bytes, for many stubs). There may be only one @samp{R} |
30047 | action per tracepoint, and it must precede any @samp{M} or @samp{X} | |
30048 | actions. Any registers referred to by @samp{M} and @samp{X} actions | |
30049 | must be collected by a preceding @samp{R} action. (The | |
30050 | ``while-stepping'' actions are treated as if they were attached to a | |
30051 | separate tracepoint, as far as these restrictions are concerned.) | |
9d29849a JB |
30052 | |
30053 | Replies: | |
30054 | @table @samp | |
30055 | @item OK | |
30056 | The packet was understood and carried out. | |
30057 | @item | |
30058 | The packet was not recognized. | |
30059 | @end table | |
30060 | ||
f61e138d SS |
30061 | @item QTDV:@var{n}:@var{value} |
30062 | @cindex define trace state variable, remote request | |
30063 | @cindex @samp{QTDV} packet | |
30064 | Create a new trace state variable, number @var{n}, with an initial | |
30065 | value of @var{value}, which is a 64-bit signed integer. Both @var{n} | |
30066 | and @var{value} are encoded as hexadecimal values. @value{GDBN} has | |
30067 | the option of not using this packet for initial values of zero; the | |
30068 | target should simply create the trace state variables as they are | |
30069 | mentioned in expressions. | |
30070 | ||
9d29849a JB |
30071 | @item QTFrame:@var{n} |
30072 | Select the @var{n}'th tracepoint frame from the buffer, and use the | |
30073 | register and memory contents recorded there to answer subsequent | |
30074 | request packets from @value{GDBN}. | |
30075 | ||
30076 | A successful reply from the stub indicates that the stub has found the | |
30077 | requested frame. The response is a series of parts, concatenated | |
30078 | without separators, describing the frame we selected. Each part has | |
30079 | one of the following forms: | |
30080 | ||
30081 | @table @samp | |
30082 | @item F @var{f} | |
30083 | The selected frame is number @var{n} in the trace frame buffer; | |
599b237a | 30084 | @var{f} is a hexadecimal number. If @var{f} is @samp{-1}, then there |
9d29849a JB |
30085 | was no frame matching the criteria in the request packet. |
30086 | ||
30087 | @item T @var{t} | |
30088 | The selected trace frame records a hit of tracepoint number @var{t}; | |
599b237a | 30089 | @var{t} is a hexadecimal number. |
9d29849a JB |
30090 | |
30091 | @end table | |
30092 | ||
30093 | @item QTFrame:pc:@var{addr} | |
30094 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
30095 | currently selected frame whose PC is @var{addr}; | |
599b237a | 30096 | @var{addr} is a hexadecimal number. |
9d29849a JB |
30097 | |
30098 | @item QTFrame:tdp:@var{t} | |
30099 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
30100 | currently selected frame that is a hit of tracepoint @var{t}; @var{t} | |
599b237a | 30101 | is a hexadecimal number. |
9d29849a JB |
30102 | |
30103 | @item QTFrame:range:@var{start}:@var{end} | |
30104 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
30105 | currently selected frame whose PC is between @var{start} (inclusive) | |
599b237a | 30106 | and @var{end} (exclusive); @var{start} and @var{end} are hexadecimal |
9d29849a JB |
30107 | numbers. |
30108 | ||
30109 | @item QTFrame:outside:@var{start}:@var{end} | |
30110 | Like @samp{QTFrame:range:@var{start}:@var{end}}, but select the first | |
30111 | frame @emph{outside} the given range of addresses. | |
30112 | ||
30113 | @item QTStart | |
30114 | Begin the tracepoint experiment. Begin collecting data from tracepoint | |
30115 | hits in the trace frame buffer. | |
30116 | ||
30117 | @item QTStop | |
30118 | End the tracepoint experiment. Stop collecting trace frames. | |
30119 | ||
30120 | @item QTinit | |
30121 | Clear the table of tracepoints, and empty the trace frame buffer. | |
30122 | ||
30123 | @item QTro:@var{start1},@var{end1}:@var{start2},@var{end2}:@dots{} | |
30124 | Establish the given ranges of memory as ``transparent''. The stub | |
30125 | will answer requests for these ranges from memory's current contents, | |
30126 | if they were not collected as part of the tracepoint hit. | |
30127 | ||
30128 | @value{GDBN} uses this to mark read-only regions of memory, like those | |
30129 | containing program code. Since these areas never change, they should | |
30130 | still have the same contents they did when the tracepoint was hit, so | |
30131 | there's no reason for the stub to refuse to provide their contents. | |
30132 | ||
30133 | @item qTStatus | |
30134 | Ask the stub if there is a trace experiment running right now. | |
30135 | ||
30136 | Replies: | |
30137 | @table @samp | |
30138 | @item T0 | |
30139 | There is no trace experiment running. | |
30140 | @item T1 | |
30141 | There is a trace experiment running. | |
30142 | @end table | |
30143 | ||
f61e138d SS |
30144 | @item qTV:@var{var} |
30145 | @cindex trace state variable value, remote request | |
30146 | @cindex @samp{qTV} packet | |
30147 | Ask the stub for the value of the trace state variable number @var{var}. | |
30148 | ||
30149 | Replies: | |
30150 | @table @samp | |
30151 | @item V@var{value} | |
30152 | The value of the variable is @var{value}. This will be the current | |
30153 | value of the variable if the user is examining a running target, or a | |
30154 | saved value if the variable was collected in the trace frame that the | |
30155 | user is looking at. Note that multiple requests may result in | |
30156 | different reply values, such as when requesting values while the | |
30157 | program is running. | |
30158 | ||
30159 | @item U | |
30160 | The value of the variable is unknown. This would occur, for example, | |
30161 | if the user is examining a trace frame in which the requested variable | |
30162 | was not collected. | |
9d29849a JB |
30163 | @end table |
30164 | ||
f61e138d | 30165 | @end table |
9d29849a | 30166 | |
a6b151f1 DJ |
30167 | @node Host I/O Packets |
30168 | @section Host I/O Packets | |
30169 | @cindex Host I/O, remote protocol | |
30170 | @cindex file transfer, remote protocol | |
30171 | ||
30172 | The @dfn{Host I/O} packets allow @value{GDBN} to perform I/O | |
30173 | operations on the far side of a remote link. For example, Host I/O is | |
30174 | used to upload and download files to a remote target with its own | |
30175 | filesystem. Host I/O uses the same constant values and data structure | |
30176 | layout as the target-initiated File-I/O protocol. However, the | |
30177 | Host I/O packets are structured differently. The target-initiated | |
30178 | protocol relies on target memory to store parameters and buffers. | |
30179 | Host I/O requests are initiated by @value{GDBN}, and the | |
30180 | target's memory is not involved. @xref{File-I/O Remote Protocol | |
30181 | Extension}, for more details on the target-initiated protocol. | |
30182 | ||
30183 | The Host I/O request packets all encode a single operation along with | |
30184 | its arguments. They have this format: | |
30185 | ||
30186 | @table @samp | |
30187 | ||
30188 | @item vFile:@var{operation}: @var{parameter}@dots{} | |
30189 | @var{operation} is the name of the particular request; the target | |
30190 | should compare the entire packet name up to the second colon when checking | |
30191 | for a supported operation. The format of @var{parameter} depends on | |
30192 | the operation. Numbers are always passed in hexadecimal. Negative | |
30193 | numbers have an explicit minus sign (i.e.@: two's complement is not | |
30194 | used). Strings (e.g.@: filenames) are encoded as a series of | |
30195 | hexadecimal bytes. The last argument to a system call may be a | |
30196 | buffer of escaped binary data (@pxref{Binary Data}). | |
30197 | ||
30198 | @end table | |
30199 | ||
30200 | The valid responses to Host I/O packets are: | |
30201 | ||
30202 | @table @samp | |
30203 | ||
30204 | @item F @var{result} [, @var{errno}] [; @var{attachment}] | |
30205 | @var{result} is the integer value returned by this operation, usually | |
30206 | non-negative for success and -1 for errors. If an error has occured, | |
30207 | @var{errno} will be included in the result. @var{errno} will have a | |
30208 | value defined by the File-I/O protocol (@pxref{Errno Values}). For | |
30209 | operations which return data, @var{attachment} supplies the data as a | |
30210 | binary buffer. Binary buffers in response packets are escaped in the | |
30211 | normal way (@pxref{Binary Data}). See the individual packet | |
30212 | documentation for the interpretation of @var{result} and | |
30213 | @var{attachment}. | |
30214 | ||
30215 | @item | |
30216 | An empty response indicates that this operation is not recognized. | |
30217 | ||
30218 | @end table | |
30219 | ||
30220 | These are the supported Host I/O operations: | |
30221 | ||
30222 | @table @samp | |
30223 | @item vFile:open: @var{pathname}, @var{flags}, @var{mode} | |
30224 | Open a file at @var{pathname} and return a file descriptor for it, or | |
30225 | return -1 if an error occurs. @var{pathname} is a string, | |
30226 | @var{flags} is an integer indicating a mask of open flags | |
30227 | (@pxref{Open Flags}), and @var{mode} is an integer indicating a mask | |
30228 | of mode bits to use if the file is created (@pxref{mode_t Values}). | |
c1c25a1a | 30229 | @xref{open}, for details of the open flags and mode values. |
a6b151f1 DJ |
30230 | |
30231 | @item vFile:close: @var{fd} | |
30232 | Close the open file corresponding to @var{fd} and return 0, or | |
30233 | -1 if an error occurs. | |
30234 | ||
30235 | @item vFile:pread: @var{fd}, @var{count}, @var{offset} | |
30236 | Read data from the open file corresponding to @var{fd}. Up to | |
30237 | @var{count} bytes will be read from the file, starting at @var{offset} | |
30238 | relative to the start of the file. The target may read fewer bytes; | |
30239 | common reasons include packet size limits and an end-of-file | |
30240 | condition. The number of bytes read is returned. Zero should only be | |
30241 | returned for a successful read at the end of the file, or if | |
30242 | @var{count} was zero. | |
30243 | ||
30244 | The data read should be returned as a binary attachment on success. | |
30245 | If zero bytes were read, the response should include an empty binary | |
30246 | attachment (i.e.@: a trailing semicolon). The return value is the | |
30247 | number of target bytes read; the binary attachment may be longer if | |
30248 | some characters were escaped. | |
30249 | ||
30250 | @item vFile:pwrite: @var{fd}, @var{offset}, @var{data} | |
30251 | Write @var{data} (a binary buffer) to the open file corresponding | |
30252 | to @var{fd}. Start the write at @var{offset} from the start of the | |
30253 | file. Unlike many @code{write} system calls, there is no | |
30254 | separate @var{count} argument; the length of @var{data} in the | |
30255 | packet is used. @samp{vFile:write} returns the number of bytes written, | |
30256 | which may be shorter than the length of @var{data}, or -1 if an | |
30257 | error occurred. | |
30258 | ||
30259 | @item vFile:unlink: @var{pathname} | |
30260 | Delete the file at @var{pathname} on the target. Return 0, | |
30261 | or -1 if an error occurs. @var{pathname} is a string. | |
30262 | ||
30263 | @end table | |
30264 | ||
9a6253be KB |
30265 | @node Interrupts |
30266 | @section Interrupts | |
30267 | @cindex interrupts (remote protocol) | |
30268 | ||
30269 | When a program on the remote target is running, @value{GDBN} may | |
9a7071a8 JB |
30270 | attempt to interrupt it by sending a @samp{Ctrl-C}, @code{BREAK} or |
30271 | a @code{BREAK} followed by @code{g}, | |
30272 | control of which is specified via @value{GDBN}'s @samp{interrupt-sequence}. | |
9a6253be KB |
30273 | |
30274 | The precise meaning of @code{BREAK} is defined by the transport | |
8775bb90 MS |
30275 | mechanism and may, in fact, be undefined. @value{GDBN} does not |
30276 | currently define a @code{BREAK} mechanism for any of the network | |
30277 | interfaces except for TCP, in which case @value{GDBN} sends the | |
30278 | @code{telnet} BREAK sequence. | |
9a6253be KB |
30279 | |
30280 | @samp{Ctrl-C}, on the other hand, is defined and implemented for all | |
30281 | transport mechanisms. It is represented by sending the single byte | |
30282 | @code{0x03} without any of the usual packet overhead described in | |
30283 | the Overview section (@pxref{Overview}). When a @code{0x03} byte is | |
30284 | transmitted as part of a packet, it is considered to be packet data | |
30285 | and does @emph{not} represent an interrupt. E.g., an @samp{X} packet | |
0876f84a | 30286 | (@pxref{X packet}), used for binary downloads, may include an unescaped |
9a6253be KB |
30287 | @code{0x03} as part of its packet. |
30288 | ||
9a7071a8 JB |
30289 | @code{BREAK} followed by @code{g} is also known as Magic SysRq g. |
30290 | When Linux kernel receives this sequence from serial port, | |
30291 | it stops execution and connects to gdb. | |
30292 | ||
9a6253be KB |
30293 | Stubs are not required to recognize these interrupt mechanisms and the |
30294 | precise meaning associated with receipt of the interrupt is | |
8b23ecc4 SL |
30295 | implementation defined. If the target supports debugging of multiple |
30296 | threads and/or processes, it should attempt to interrupt all | |
30297 | currently-executing threads and processes. | |
30298 | If the stub is successful at interrupting the | |
30299 | running program, it should send one of the stop | |
30300 | reply packets (@pxref{Stop Reply Packets}) to @value{GDBN} as a result | |
30301 | of successfully stopping the program in all-stop mode, and a stop reply | |
30302 | for each stopped thread in non-stop mode. | |
30303 | Interrupts received while the | |
30304 | program is stopped are discarded. | |
30305 | ||
30306 | @node Notification Packets | |
30307 | @section Notification Packets | |
30308 | @cindex notification packets | |
30309 | @cindex packets, notification | |
30310 | ||
30311 | The @value{GDBN} remote serial protocol includes @dfn{notifications}, | |
30312 | packets that require no acknowledgment. Both the GDB and the stub | |
30313 | may send notifications (although the only notifications defined at | |
30314 | present are sent by the stub). Notifications carry information | |
30315 | without incurring the round-trip latency of an acknowledgment, and so | |
30316 | are useful for low-impact communications where occasional packet loss | |
30317 | is not a problem. | |
30318 | ||
30319 | A notification packet has the form @samp{% @var{data} # | |
30320 | @var{checksum}}, where @var{data} is the content of the notification, | |
30321 | and @var{checksum} is a checksum of @var{data}, computed and formatted | |
30322 | as for ordinary @value{GDBN} packets. A notification's @var{data} | |
30323 | never contains @samp{$}, @samp{%} or @samp{#} characters. Upon | |
30324 | receiving a notification, the recipient sends no @samp{+} or @samp{-} | |
30325 | to acknowledge the notification's receipt or to report its corruption. | |
30326 | ||
30327 | Every notification's @var{data} begins with a name, which contains no | |
30328 | colon characters, followed by a colon character. | |
30329 | ||
30330 | Recipients should silently ignore corrupted notifications and | |
30331 | notifications they do not understand. Recipients should restart | |
30332 | timeout periods on receipt of a well-formed notification, whether or | |
30333 | not they understand it. | |
30334 | ||
30335 | Senders should only send the notifications described here when this | |
30336 | protocol description specifies that they are permitted. In the | |
30337 | future, we may extend the protocol to permit existing notifications in | |
30338 | new contexts; this rule helps older senders avoid confusing newer | |
30339 | recipients. | |
30340 | ||
30341 | (Older versions of @value{GDBN} ignore bytes received until they see | |
30342 | the @samp{$} byte that begins an ordinary packet, so new stubs may | |
30343 | transmit notifications without fear of confusing older clients. There | |
30344 | are no notifications defined for @value{GDBN} to send at the moment, but we | |
30345 | assume that most older stubs would ignore them, as well.) | |
30346 | ||
30347 | The following notification packets from the stub to @value{GDBN} are | |
30348 | defined: | |
30349 | ||
30350 | @table @samp | |
30351 | @item Stop: @var{reply} | |
30352 | Report an asynchronous stop event in non-stop mode. | |
30353 | The @var{reply} has the form of a stop reply, as | |
30354 | described in @ref{Stop Reply Packets}. Refer to @ref{Remote Non-Stop}, | |
30355 | for information on how these notifications are acknowledged by | |
30356 | @value{GDBN}. | |
30357 | @end table | |
30358 | ||
30359 | @node Remote Non-Stop | |
30360 | @section Remote Protocol Support for Non-Stop Mode | |
30361 | ||
30362 | @value{GDBN}'s remote protocol supports non-stop debugging of | |
30363 | multi-threaded programs, as described in @ref{Non-Stop Mode}. If the stub | |
30364 | supports non-stop mode, it should report that to @value{GDBN} by including | |
30365 | @samp{QNonStop+} in its @samp{qSupported} response (@pxref{qSupported}). | |
30366 | ||
30367 | @value{GDBN} typically sends a @samp{QNonStop} packet only when | |
30368 | establishing a new connection with the stub. Entering non-stop mode | |
30369 | does not alter the state of any currently-running threads, but targets | |
30370 | must stop all threads in any already-attached processes when entering | |
30371 | all-stop mode. @value{GDBN} uses the @samp{?} packet as necessary to | |
30372 | probe the target state after a mode change. | |
30373 | ||
30374 | In non-stop mode, when an attached process encounters an event that | |
30375 | would otherwise be reported with a stop reply, it uses the | |
30376 | asynchronous notification mechanism (@pxref{Notification Packets}) to | |
30377 | inform @value{GDBN}. In contrast to all-stop mode, where all threads | |
30378 | in all processes are stopped when a stop reply is sent, in non-stop | |
30379 | mode only the thread reporting the stop event is stopped. That is, | |
30380 | when reporting a @samp{S} or @samp{T} response to indicate completion | |
30381 | of a step operation, hitting a breakpoint, or a fault, only the | |
30382 | affected thread is stopped; any other still-running threads continue | |
30383 | to run. When reporting a @samp{W} or @samp{X} response, all running | |
30384 | threads belonging to other attached processes continue to run. | |
30385 | ||
30386 | Only one stop reply notification at a time may be pending; if | |
30387 | additional stop events occur before @value{GDBN} has acknowledged the | |
30388 | previous notification, they must be queued by the stub for later | |
30389 | synchronous transmission in response to @samp{vStopped} packets from | |
30390 | @value{GDBN}. Because the notification mechanism is unreliable, | |
30391 | the stub is permitted to resend a stop reply notification | |
30392 | if it believes @value{GDBN} may not have received it. @value{GDBN} | |
30393 | ignores additional stop reply notifications received before it has | |
30394 | finished processing a previous notification and the stub has completed | |
30395 | sending any queued stop events. | |
30396 | ||
30397 | Otherwise, @value{GDBN} must be prepared to receive a stop reply | |
30398 | notification at any time. Specifically, they may appear when | |
30399 | @value{GDBN} is not otherwise reading input from the stub, or when | |
30400 | @value{GDBN} is expecting to read a normal synchronous response or a | |
30401 | @samp{+}/@samp{-} acknowledgment to a packet it has sent. | |
30402 | Notification packets are distinct from any other communication from | |
30403 | the stub so there is no ambiguity. | |
30404 | ||
30405 | After receiving a stop reply notification, @value{GDBN} shall | |
30406 | acknowledge it by sending a @samp{vStopped} packet (@pxref{vStopped packet}) | |
30407 | as a regular, synchronous request to the stub. Such acknowledgment | |
30408 | is not required to happen immediately, as @value{GDBN} is permitted to | |
30409 | send other, unrelated packets to the stub first, which the stub should | |
30410 | process normally. | |
30411 | ||
30412 | Upon receiving a @samp{vStopped} packet, if the stub has other queued | |
30413 | stop events to report to @value{GDBN}, it shall respond by sending a | |
30414 | normal stop reply response. @value{GDBN} shall then send another | |
30415 | @samp{vStopped} packet to solicit further responses; again, it is | |
30416 | permitted to send other, unrelated packets as well which the stub | |
30417 | should process normally. | |
30418 | ||
30419 | If the stub receives a @samp{vStopped} packet and there are no | |
30420 | additional stop events to report, the stub shall return an @samp{OK} | |
30421 | response. At this point, if further stop events occur, the stub shall | |
30422 | send a new stop reply notification, @value{GDBN} shall accept the | |
30423 | notification, and the process shall be repeated. | |
30424 | ||
30425 | In non-stop mode, the target shall respond to the @samp{?} packet as | |
30426 | follows. First, any incomplete stop reply notification/@samp{vStopped} | |
30427 | sequence in progress is abandoned. The target must begin a new | |
30428 | sequence reporting stop events for all stopped threads, whether or not | |
30429 | it has previously reported those events to @value{GDBN}. The first | |
30430 | stop reply is sent as a synchronous reply to the @samp{?} packet, and | |
30431 | subsequent stop replies are sent as responses to @samp{vStopped} packets | |
30432 | using the mechanism described above. The target must not send | |
30433 | asynchronous stop reply notifications until the sequence is complete. | |
30434 | If all threads are running when the target receives the @samp{?} packet, | |
30435 | or if the target is not attached to any process, it shall respond | |
30436 | @samp{OK}. | |
9a6253be | 30437 | |
a6f3e723 SL |
30438 | @node Packet Acknowledgment |
30439 | @section Packet Acknowledgment | |
30440 | ||
30441 | @cindex acknowledgment, for @value{GDBN} remote | |
30442 | @cindex packet acknowledgment, for @value{GDBN} remote | |
30443 | By default, when either the host or the target machine receives a packet, | |
30444 | the first response expected is an acknowledgment: either @samp{+} (to indicate | |
30445 | the package was received correctly) or @samp{-} (to request retransmission). | |
30446 | This mechanism allows the @value{GDBN} remote protocol to operate over | |
30447 | unreliable transport mechanisms, such as a serial line. | |
30448 | ||
30449 | In cases where the transport mechanism is itself reliable (such as a pipe or | |
30450 | TCP connection), the @samp{+}/@samp{-} acknowledgments are redundant. | |
30451 | It may be desirable to disable them in that case to reduce communication | |
30452 | overhead, or for other reasons. This can be accomplished by means of the | |
30453 | @samp{QStartNoAckMode} packet; @pxref{QStartNoAckMode}. | |
30454 | ||
30455 | When in no-acknowledgment mode, neither the stub nor @value{GDBN} shall send or | |
30456 | expect @samp{+}/@samp{-} protocol acknowledgments. The packet | |
30457 | and response format still includes the normal checksum, as described in | |
30458 | @ref{Overview}, but the checksum may be ignored by the receiver. | |
30459 | ||
30460 | If the stub supports @samp{QStartNoAckMode} and prefers to operate in | |
30461 | no-acknowledgment mode, it should report that to @value{GDBN} | |
30462 | by including @samp{QStartNoAckMode+} in its response to @samp{qSupported}; | |
30463 | @pxref{qSupported}. | |
30464 | If @value{GDBN} also supports @samp{QStartNoAckMode} and it has not been | |
30465 | disabled via the @code{set remote noack-packet off} command | |
30466 | (@pxref{Remote Configuration}), | |
30467 | @value{GDBN} may then send a @samp{QStartNoAckMode} packet to the stub. | |
30468 | Only then may the stub actually turn off packet acknowledgments. | |
30469 | @value{GDBN} sends a final @samp{+} acknowledgment of the stub's @samp{OK} | |
30470 | response, which can be safely ignored by the stub. | |
30471 | ||
30472 | Note that @code{set remote noack-packet} command only affects negotiation | |
30473 | between @value{GDBN} and the stub when subsequent connections are made; | |
30474 | it does not affect the protocol acknowledgment state for any current | |
30475 | connection. | |
30476 | Since @samp{+}/@samp{-} acknowledgments are enabled by default when a | |
30477 | new connection is established, | |
30478 | there is also no protocol request to re-enable the acknowledgments | |
30479 | for the current connection, once disabled. | |
30480 | ||
ee2d5c50 AC |
30481 | @node Examples |
30482 | @section Examples | |
eb12ee30 | 30483 | |
8e04817f AC |
30484 | Example sequence of a target being re-started. Notice how the restart |
30485 | does not get any direct output: | |
eb12ee30 | 30486 | |
474c8240 | 30487 | @smallexample |
d2c6833e AC |
30488 | -> @code{R00} |
30489 | <- @code{+} | |
8e04817f | 30490 | @emph{target restarts} |
d2c6833e | 30491 | -> @code{?} |
8e04817f | 30492 | <- @code{+} |
d2c6833e AC |
30493 | <- @code{T001:1234123412341234} |
30494 | -> @code{+} | |
474c8240 | 30495 | @end smallexample |
eb12ee30 | 30496 | |
8e04817f | 30497 | Example sequence of a target being stepped by a single instruction: |
eb12ee30 | 30498 | |
474c8240 | 30499 | @smallexample |
d2c6833e | 30500 | -> @code{G1445@dots{}} |
8e04817f | 30501 | <- @code{+} |
d2c6833e AC |
30502 | -> @code{s} |
30503 | <- @code{+} | |
30504 | @emph{time passes} | |
30505 | <- @code{T001:1234123412341234} | |
8e04817f | 30506 | -> @code{+} |
d2c6833e | 30507 | -> @code{g} |
8e04817f | 30508 | <- @code{+} |
d2c6833e AC |
30509 | <- @code{1455@dots{}} |
30510 | -> @code{+} | |
474c8240 | 30511 | @end smallexample |
eb12ee30 | 30512 | |
79a6e687 BW |
30513 | @node File-I/O Remote Protocol Extension |
30514 | @section File-I/O Remote Protocol Extension | |
0ce1b118 CV |
30515 | @cindex File-I/O remote protocol extension |
30516 | ||
30517 | @menu | |
30518 | * File-I/O Overview:: | |
79a6e687 BW |
30519 | * Protocol Basics:: |
30520 | * The F Request Packet:: | |
30521 | * The F Reply Packet:: | |
30522 | * The Ctrl-C Message:: | |
0ce1b118 | 30523 | * Console I/O:: |
79a6e687 | 30524 | * List of Supported Calls:: |
db2e3e2e | 30525 | * Protocol-specific Representation of Datatypes:: |
0ce1b118 CV |
30526 | * Constants:: |
30527 | * File-I/O Examples:: | |
30528 | @end menu | |
30529 | ||
30530 | @node File-I/O Overview | |
30531 | @subsection File-I/O Overview | |
30532 | @cindex file-i/o overview | |
30533 | ||
9c16f35a | 30534 | The @dfn{File I/O remote protocol extension} (short: File-I/O) allows the |
fc320d37 | 30535 | target to use the host's file system and console I/O to perform various |
0ce1b118 | 30536 | system calls. System calls on the target system are translated into a |
fc320d37 SL |
30537 | remote protocol packet to the host system, which then performs the needed |
30538 | actions and returns a response packet to the target system. | |
0ce1b118 CV |
30539 | This simulates file system operations even on targets that lack file systems. |
30540 | ||
fc320d37 SL |
30541 | The protocol is defined to be independent of both the host and target systems. |
30542 | It uses its own internal representation of datatypes and values. Both | |
0ce1b118 | 30543 | @value{GDBN} and the target's @value{GDBN} stub are responsible for |
fc320d37 SL |
30544 | translating the system-dependent value representations into the internal |
30545 | protocol representations when data is transmitted. | |
0ce1b118 | 30546 | |
fc320d37 SL |
30547 | The communication is synchronous. A system call is possible only when |
30548 | @value{GDBN} is waiting for a response from the @samp{C}, @samp{c}, @samp{S} | |
30549 | or @samp{s} packets. While @value{GDBN} handles the request for a system call, | |
0ce1b118 | 30550 | the target is stopped to allow deterministic access to the target's |
fc320d37 SL |
30551 | memory. Therefore File-I/O is not interruptible by target signals. On |
30552 | the other hand, it is possible to interrupt File-I/O by a user interrupt | |
c8aa23ab | 30553 | (@samp{Ctrl-C}) within @value{GDBN}. |
0ce1b118 CV |
30554 | |
30555 | The target's request to perform a host system call does not finish | |
30556 | the latest @samp{C}, @samp{c}, @samp{S} or @samp{s} action. That means, | |
30557 | after finishing the system call, the target returns to continuing the | |
30558 | previous activity (continue, step). No additional continue or step | |
30559 | request from @value{GDBN} is required. | |
30560 | ||
30561 | @smallexample | |
f7dc1244 | 30562 | (@value{GDBP}) continue |
0ce1b118 CV |
30563 | <- target requests 'system call X' |
30564 | target is stopped, @value{GDBN} executes system call | |
3f94c067 BW |
30565 | -> @value{GDBN} returns result |
30566 | ... target continues, @value{GDBN} returns to wait for the target | |
0ce1b118 CV |
30567 | <- target hits breakpoint and sends a Txx packet |
30568 | @end smallexample | |
30569 | ||
fc320d37 SL |
30570 | The protocol only supports I/O on the console and to regular files on |
30571 | the host file system. Character or block special devices, pipes, | |
30572 | named pipes, sockets or any other communication method on the host | |
0ce1b118 CV |
30573 | system are not supported by this protocol. |
30574 | ||
8b23ecc4 SL |
30575 | File I/O is not supported in non-stop mode. |
30576 | ||
79a6e687 BW |
30577 | @node Protocol Basics |
30578 | @subsection Protocol Basics | |
0ce1b118 CV |
30579 | @cindex protocol basics, file-i/o |
30580 | ||
fc320d37 SL |
30581 | The File-I/O protocol uses the @code{F} packet as the request as well |
30582 | as reply packet. Since a File-I/O system call can only occur when | |
30583 | @value{GDBN} is waiting for a response from the continuing or stepping target, | |
30584 | the File-I/O request is a reply that @value{GDBN} has to expect as a result | |
30585 | of a previous @samp{C}, @samp{c}, @samp{S} or @samp{s} packet. | |
0ce1b118 CV |
30586 | This @code{F} packet contains all information needed to allow @value{GDBN} |
30587 | to call the appropriate host system call: | |
30588 | ||
30589 | @itemize @bullet | |
b383017d | 30590 | @item |
0ce1b118 CV |
30591 | A unique identifier for the requested system call. |
30592 | ||
30593 | @item | |
30594 | All parameters to the system call. Pointers are given as addresses | |
30595 | in the target memory address space. Pointers to strings are given as | |
b383017d | 30596 | pointer/length pair. Numerical values are given as they are. |
db2e3e2e | 30597 | Numerical control flags are given in a protocol-specific representation. |
0ce1b118 CV |
30598 | |
30599 | @end itemize | |
30600 | ||
fc320d37 | 30601 | At this point, @value{GDBN} has to perform the following actions. |
0ce1b118 CV |
30602 | |
30603 | @itemize @bullet | |
b383017d | 30604 | @item |
fc320d37 SL |
30605 | If the parameters include pointer values to data needed as input to a |
30606 | system call, @value{GDBN} requests this data from the target with a | |
0ce1b118 CV |
30607 | standard @code{m} packet request. This additional communication has to be |
30608 | expected by the target implementation and is handled as any other @code{m} | |
30609 | packet. | |
30610 | ||
30611 | @item | |
30612 | @value{GDBN} translates all value from protocol representation to host | |
30613 | representation as needed. Datatypes are coerced into the host types. | |
30614 | ||
30615 | @item | |
fc320d37 | 30616 | @value{GDBN} calls the system call. |
0ce1b118 CV |
30617 | |
30618 | @item | |
30619 | It then coerces datatypes back to protocol representation. | |
30620 | ||
30621 | @item | |
fc320d37 SL |
30622 | If the system call is expected to return data in buffer space specified |
30623 | by pointer parameters to the call, the data is transmitted to the | |
0ce1b118 CV |
30624 | target using a @code{M} or @code{X} packet. This packet has to be expected |
30625 | by the target implementation and is handled as any other @code{M} or @code{X} | |
30626 | packet. | |
30627 | ||
30628 | @end itemize | |
30629 | ||
30630 | Eventually @value{GDBN} replies with another @code{F} packet which contains all | |
30631 | necessary information for the target to continue. This at least contains | |
30632 | ||
30633 | @itemize @bullet | |
30634 | @item | |
30635 | Return value. | |
30636 | ||
30637 | @item | |
30638 | @code{errno}, if has been changed by the system call. | |
30639 | ||
30640 | @item | |
30641 | ``Ctrl-C'' flag. | |
30642 | ||
30643 | @end itemize | |
30644 | ||
30645 | After having done the needed type and value coercion, the target continues | |
30646 | the latest continue or step action. | |
30647 | ||
79a6e687 BW |
30648 | @node The F Request Packet |
30649 | @subsection The @code{F} Request Packet | |
0ce1b118 CV |
30650 | @cindex file-i/o request packet |
30651 | @cindex @code{F} request packet | |
30652 | ||
30653 | The @code{F} request packet has the following format: | |
30654 | ||
30655 | @table @samp | |
fc320d37 | 30656 | @item F@var{call-id},@var{parameter@dots{}} |
0ce1b118 CV |
30657 | |
30658 | @var{call-id} is the identifier to indicate the host system call to be called. | |
30659 | This is just the name of the function. | |
30660 | ||
fc320d37 SL |
30661 | @var{parameter@dots{}} are the parameters to the system call. |
30662 | Parameters are hexadecimal integer values, either the actual values in case | |
30663 | of scalar datatypes, pointers to target buffer space in case of compound | |
30664 | datatypes and unspecified memory areas, or pointer/length pairs in case | |
30665 | of string parameters. These are appended to the @var{call-id} as a | |
30666 | comma-delimited list. All values are transmitted in ASCII | |
30667 | string representation, pointer/length pairs separated by a slash. | |
0ce1b118 | 30668 | |
b383017d | 30669 | @end table |
0ce1b118 | 30670 | |
fc320d37 | 30671 | |
0ce1b118 | 30672 | |
79a6e687 BW |
30673 | @node The F Reply Packet |
30674 | @subsection The @code{F} Reply Packet | |
0ce1b118 CV |
30675 | @cindex file-i/o reply packet |
30676 | @cindex @code{F} reply packet | |
30677 | ||
30678 | The @code{F} reply packet has the following format: | |
30679 | ||
30680 | @table @samp | |
30681 | ||
d3bdde98 | 30682 | @item F@var{retcode},@var{errno},@var{Ctrl-C flag};@var{call-specific attachment} |
0ce1b118 CV |
30683 | |
30684 | @var{retcode} is the return code of the system call as hexadecimal value. | |
30685 | ||
db2e3e2e BW |
30686 | @var{errno} is the @code{errno} set by the call, in protocol-specific |
30687 | representation. | |
0ce1b118 CV |
30688 | This parameter can be omitted if the call was successful. |
30689 | ||
fc320d37 SL |
30690 | @var{Ctrl-C flag} is only sent if the user requested a break. In this |
30691 | case, @var{errno} must be sent as well, even if the call was successful. | |
30692 | The @var{Ctrl-C flag} itself consists of the character @samp{C}: | |
0ce1b118 CV |
30693 | |
30694 | @smallexample | |
30695 | F0,0,C | |
30696 | @end smallexample | |
30697 | ||
30698 | @noindent | |
fc320d37 | 30699 | or, if the call was interrupted before the host call has been performed: |
0ce1b118 CV |
30700 | |
30701 | @smallexample | |
30702 | F-1,4,C | |
30703 | @end smallexample | |
30704 | ||
30705 | @noindent | |
db2e3e2e | 30706 | assuming 4 is the protocol-specific representation of @code{EINTR}. |
0ce1b118 CV |
30707 | |
30708 | @end table | |
30709 | ||
0ce1b118 | 30710 | |
79a6e687 BW |
30711 | @node The Ctrl-C Message |
30712 | @subsection The @samp{Ctrl-C} Message | |
0ce1b118 CV |
30713 | @cindex ctrl-c message, in file-i/o protocol |
30714 | ||
c8aa23ab | 30715 | If the @samp{Ctrl-C} flag is set in the @value{GDBN} |
79a6e687 | 30716 | reply packet (@pxref{The F Reply Packet}), |
fc320d37 | 30717 | the target should behave as if it had |
0ce1b118 | 30718 | gotten a break message. The meaning for the target is ``system call |
fc320d37 | 30719 | interrupted by @code{SIGINT}''. Consequentially, the target should actually stop |
0ce1b118 | 30720 | (as with a break message) and return to @value{GDBN} with a @code{T02} |
c8aa23ab | 30721 | packet. |
fc320d37 SL |
30722 | |
30723 | It's important for the target to know in which | |
30724 | state the system call was interrupted. There are two possible cases: | |
0ce1b118 CV |
30725 | |
30726 | @itemize @bullet | |
30727 | @item | |
30728 | The system call hasn't been performed on the host yet. | |
30729 | ||
30730 | @item | |
30731 | The system call on the host has been finished. | |
30732 | ||
30733 | @end itemize | |
30734 | ||
30735 | These two states can be distinguished by the target by the value of the | |
30736 | returned @code{errno}. If it's the protocol representation of @code{EINTR}, the system | |
30737 | call hasn't been performed. This is equivalent to the @code{EINTR} handling | |
30738 | on POSIX systems. In any other case, the target may presume that the | |
fc320d37 | 30739 | system call has been finished --- successfully or not --- and should behave |
0ce1b118 CV |
30740 | as if the break message arrived right after the system call. |
30741 | ||
fc320d37 | 30742 | @value{GDBN} must behave reliably. If the system call has not been called |
0ce1b118 CV |
30743 | yet, @value{GDBN} may send the @code{F} reply immediately, setting @code{EINTR} as |
30744 | @code{errno} in the packet. If the system call on the host has been finished | |
fc320d37 SL |
30745 | before the user requests a break, the full action must be finished by |
30746 | @value{GDBN}. This requires sending @code{M} or @code{X} packets as necessary. | |
30747 | The @code{F} packet may only be sent when either nothing has happened | |
0ce1b118 CV |
30748 | or the full action has been completed. |
30749 | ||
30750 | @node Console I/O | |
30751 | @subsection Console I/O | |
30752 | @cindex console i/o as part of file-i/o | |
30753 | ||
d3e8051b | 30754 | By default and if not explicitly closed by the target system, the file |
0ce1b118 CV |
30755 | descriptors 0, 1 and 2 are connected to the @value{GDBN} console. Output |
30756 | on the @value{GDBN} console is handled as any other file output operation | |
30757 | (@code{write(1, @dots{})} or @code{write(2, @dots{})}). Console input is handled | |
30758 | by @value{GDBN} so that after the target read request from file descriptor | |
30759 | 0 all following typing is buffered until either one of the following | |
30760 | conditions is met: | |
30761 | ||
30762 | @itemize @bullet | |
30763 | @item | |
c8aa23ab | 30764 | The user types @kbd{Ctrl-c}. The behaviour is as explained above, and the |
0ce1b118 CV |
30765 | @code{read} |
30766 | system call is treated as finished. | |
30767 | ||
30768 | @item | |
7f9087cb | 30769 | The user presses @key{RET}. This is treated as end of input with a trailing |
fc320d37 | 30770 | newline. |
0ce1b118 CV |
30771 | |
30772 | @item | |
c8aa23ab EZ |
30773 | The user types @kbd{Ctrl-d}. This is treated as end of input. No trailing |
30774 | character (neither newline nor @samp{Ctrl-D}) is appended to the input. | |
0ce1b118 CV |
30775 | |
30776 | @end itemize | |
30777 | ||
fc320d37 SL |
30778 | If the user has typed more characters than fit in the buffer given to |
30779 | the @code{read} call, the trailing characters are buffered in @value{GDBN} until | |
30780 | either another @code{read(0, @dots{})} is requested by the target, or debugging | |
30781 | is stopped at the user's request. | |
0ce1b118 | 30782 | |
0ce1b118 | 30783 | |
79a6e687 BW |
30784 | @node List of Supported Calls |
30785 | @subsection List of Supported Calls | |
0ce1b118 CV |
30786 | @cindex list of supported file-i/o calls |
30787 | ||
30788 | @menu | |
30789 | * open:: | |
30790 | * close:: | |
30791 | * read:: | |
30792 | * write:: | |
30793 | * lseek:: | |
30794 | * rename:: | |
30795 | * unlink:: | |
30796 | * stat/fstat:: | |
30797 | * gettimeofday:: | |
30798 | * isatty:: | |
30799 | * system:: | |
30800 | @end menu | |
30801 | ||
30802 | @node open | |
30803 | @unnumberedsubsubsec open | |
30804 | @cindex open, file-i/o system call | |
30805 | ||
fc320d37 SL |
30806 | @table @asis |
30807 | @item Synopsis: | |
0ce1b118 | 30808 | @smallexample |
0ce1b118 CV |
30809 | int open(const char *pathname, int flags); |
30810 | int open(const char *pathname, int flags, mode_t mode); | |
0ce1b118 CV |
30811 | @end smallexample |
30812 | ||
fc320d37 SL |
30813 | @item Request: |
30814 | @samp{Fopen,@var{pathptr}/@var{len},@var{flags},@var{mode}} | |
30815 | ||
0ce1b118 | 30816 | @noindent |
fc320d37 | 30817 | @var{flags} is the bitwise @code{OR} of the following values: |
0ce1b118 CV |
30818 | |
30819 | @table @code | |
b383017d | 30820 | @item O_CREAT |
0ce1b118 CV |
30821 | If the file does not exist it will be created. The host |
30822 | rules apply as far as file ownership and time stamps | |
30823 | are concerned. | |
30824 | ||
b383017d | 30825 | @item O_EXCL |
fc320d37 | 30826 | When used with @code{O_CREAT}, if the file already exists it is |
0ce1b118 CV |
30827 | an error and open() fails. |
30828 | ||
b383017d | 30829 | @item O_TRUNC |
0ce1b118 | 30830 | If the file already exists and the open mode allows |
fc320d37 SL |
30831 | writing (@code{O_RDWR} or @code{O_WRONLY} is given) it will be |
30832 | truncated to zero length. | |
0ce1b118 | 30833 | |
b383017d | 30834 | @item O_APPEND |
0ce1b118 CV |
30835 | The file is opened in append mode. |
30836 | ||
b383017d | 30837 | @item O_RDONLY |
0ce1b118 CV |
30838 | The file is opened for reading only. |
30839 | ||
b383017d | 30840 | @item O_WRONLY |
0ce1b118 CV |
30841 | The file is opened for writing only. |
30842 | ||
b383017d | 30843 | @item O_RDWR |
0ce1b118 | 30844 | The file is opened for reading and writing. |
fc320d37 | 30845 | @end table |
0ce1b118 CV |
30846 | |
30847 | @noindent | |
fc320d37 | 30848 | Other bits are silently ignored. |
0ce1b118 | 30849 | |
0ce1b118 CV |
30850 | |
30851 | @noindent | |
fc320d37 | 30852 | @var{mode} is the bitwise @code{OR} of the following values: |
0ce1b118 CV |
30853 | |
30854 | @table @code | |
b383017d | 30855 | @item S_IRUSR |
0ce1b118 CV |
30856 | User has read permission. |
30857 | ||
b383017d | 30858 | @item S_IWUSR |
0ce1b118 CV |
30859 | User has write permission. |
30860 | ||
b383017d | 30861 | @item S_IRGRP |
0ce1b118 CV |
30862 | Group has read permission. |
30863 | ||
b383017d | 30864 | @item S_IWGRP |
0ce1b118 CV |
30865 | Group has write permission. |
30866 | ||
b383017d | 30867 | @item S_IROTH |
0ce1b118 CV |
30868 | Others have read permission. |
30869 | ||
b383017d | 30870 | @item S_IWOTH |
0ce1b118 | 30871 | Others have write permission. |
fc320d37 | 30872 | @end table |
0ce1b118 CV |
30873 | |
30874 | @noindent | |
fc320d37 | 30875 | Other bits are silently ignored. |
0ce1b118 | 30876 | |
0ce1b118 | 30877 | |
fc320d37 SL |
30878 | @item Return value: |
30879 | @code{open} returns the new file descriptor or -1 if an error | |
30880 | occurred. | |
0ce1b118 | 30881 | |
fc320d37 | 30882 | @item Errors: |
0ce1b118 CV |
30883 | |
30884 | @table @code | |
b383017d | 30885 | @item EEXIST |
fc320d37 | 30886 | @var{pathname} already exists and @code{O_CREAT} and @code{O_EXCL} were used. |
0ce1b118 | 30887 | |
b383017d | 30888 | @item EISDIR |
fc320d37 | 30889 | @var{pathname} refers to a directory. |
0ce1b118 | 30890 | |
b383017d | 30891 | @item EACCES |
0ce1b118 CV |
30892 | The requested access is not allowed. |
30893 | ||
30894 | @item ENAMETOOLONG | |
fc320d37 | 30895 | @var{pathname} was too long. |
0ce1b118 | 30896 | |
b383017d | 30897 | @item ENOENT |
fc320d37 | 30898 | A directory component in @var{pathname} does not exist. |
0ce1b118 | 30899 | |
b383017d | 30900 | @item ENODEV |
fc320d37 | 30901 | @var{pathname} refers to a device, pipe, named pipe or socket. |
0ce1b118 | 30902 | |
b383017d | 30903 | @item EROFS |
fc320d37 | 30904 | @var{pathname} refers to a file on a read-only filesystem and |
0ce1b118 CV |
30905 | write access was requested. |
30906 | ||
b383017d | 30907 | @item EFAULT |
fc320d37 | 30908 | @var{pathname} is an invalid pointer value. |
0ce1b118 | 30909 | |
b383017d | 30910 | @item ENOSPC |
0ce1b118 CV |
30911 | No space on device to create the file. |
30912 | ||
b383017d | 30913 | @item EMFILE |
0ce1b118 CV |
30914 | The process already has the maximum number of files open. |
30915 | ||
b383017d | 30916 | @item ENFILE |
0ce1b118 CV |
30917 | The limit on the total number of files open on the system |
30918 | has been reached. | |
30919 | ||
b383017d | 30920 | @item EINTR |
0ce1b118 CV |
30921 | The call was interrupted by the user. |
30922 | @end table | |
30923 | ||
fc320d37 SL |
30924 | @end table |
30925 | ||
0ce1b118 CV |
30926 | @node close |
30927 | @unnumberedsubsubsec close | |
30928 | @cindex close, file-i/o system call | |
30929 | ||
fc320d37 SL |
30930 | @table @asis |
30931 | @item Synopsis: | |
0ce1b118 | 30932 | @smallexample |
0ce1b118 | 30933 | int close(int fd); |
fc320d37 | 30934 | @end smallexample |
0ce1b118 | 30935 | |
fc320d37 SL |
30936 | @item Request: |
30937 | @samp{Fclose,@var{fd}} | |
0ce1b118 | 30938 | |
fc320d37 SL |
30939 | @item Return value: |
30940 | @code{close} returns zero on success, or -1 if an error occurred. | |
0ce1b118 | 30941 | |
fc320d37 | 30942 | @item Errors: |
0ce1b118 CV |
30943 | |
30944 | @table @code | |
b383017d | 30945 | @item EBADF |
fc320d37 | 30946 | @var{fd} isn't a valid open file descriptor. |
0ce1b118 | 30947 | |
b383017d | 30948 | @item EINTR |
0ce1b118 CV |
30949 | The call was interrupted by the user. |
30950 | @end table | |
30951 | ||
fc320d37 SL |
30952 | @end table |
30953 | ||
0ce1b118 CV |
30954 | @node read |
30955 | @unnumberedsubsubsec read | |
30956 | @cindex read, file-i/o system call | |
30957 | ||
fc320d37 SL |
30958 | @table @asis |
30959 | @item Synopsis: | |
0ce1b118 | 30960 | @smallexample |
0ce1b118 | 30961 | int read(int fd, void *buf, unsigned int count); |
fc320d37 | 30962 | @end smallexample |
0ce1b118 | 30963 | |
fc320d37 SL |
30964 | @item Request: |
30965 | @samp{Fread,@var{fd},@var{bufptr},@var{count}} | |
0ce1b118 | 30966 | |
fc320d37 | 30967 | @item Return value: |
0ce1b118 CV |
30968 | On success, the number of bytes read is returned. |
30969 | Zero indicates end of file. If count is zero, read | |
b383017d | 30970 | returns zero as well. On error, -1 is returned. |
0ce1b118 | 30971 | |
fc320d37 | 30972 | @item Errors: |
0ce1b118 CV |
30973 | |
30974 | @table @code | |
b383017d | 30975 | @item EBADF |
fc320d37 | 30976 | @var{fd} is not a valid file descriptor or is not open for |
0ce1b118 CV |
30977 | reading. |
30978 | ||
b383017d | 30979 | @item EFAULT |
fc320d37 | 30980 | @var{bufptr} is an invalid pointer value. |
0ce1b118 | 30981 | |
b383017d | 30982 | @item EINTR |
0ce1b118 CV |
30983 | The call was interrupted by the user. |
30984 | @end table | |
30985 | ||
fc320d37 SL |
30986 | @end table |
30987 | ||
0ce1b118 CV |
30988 | @node write |
30989 | @unnumberedsubsubsec write | |
30990 | @cindex write, file-i/o system call | |
30991 | ||
fc320d37 SL |
30992 | @table @asis |
30993 | @item Synopsis: | |
0ce1b118 | 30994 | @smallexample |
0ce1b118 | 30995 | int write(int fd, const void *buf, unsigned int count); |
fc320d37 | 30996 | @end smallexample |
0ce1b118 | 30997 | |
fc320d37 SL |
30998 | @item Request: |
30999 | @samp{Fwrite,@var{fd},@var{bufptr},@var{count}} | |
0ce1b118 | 31000 | |
fc320d37 | 31001 | @item Return value: |
0ce1b118 CV |
31002 | On success, the number of bytes written are returned. |
31003 | Zero indicates nothing was written. On error, -1 | |
31004 | is returned. | |
31005 | ||
fc320d37 | 31006 | @item Errors: |
0ce1b118 CV |
31007 | |
31008 | @table @code | |
b383017d | 31009 | @item EBADF |
fc320d37 | 31010 | @var{fd} is not a valid file descriptor or is not open for |
0ce1b118 CV |
31011 | writing. |
31012 | ||
b383017d | 31013 | @item EFAULT |
fc320d37 | 31014 | @var{bufptr} is an invalid pointer value. |
0ce1b118 | 31015 | |
b383017d | 31016 | @item EFBIG |
0ce1b118 | 31017 | An attempt was made to write a file that exceeds the |
db2e3e2e | 31018 | host-specific maximum file size allowed. |
0ce1b118 | 31019 | |
b383017d | 31020 | @item ENOSPC |
0ce1b118 CV |
31021 | No space on device to write the data. |
31022 | ||
b383017d | 31023 | @item EINTR |
0ce1b118 CV |
31024 | The call was interrupted by the user. |
31025 | @end table | |
31026 | ||
fc320d37 SL |
31027 | @end table |
31028 | ||
0ce1b118 CV |
31029 | @node lseek |
31030 | @unnumberedsubsubsec lseek | |
31031 | @cindex lseek, file-i/o system call | |
31032 | ||
fc320d37 SL |
31033 | @table @asis |
31034 | @item Synopsis: | |
0ce1b118 | 31035 | @smallexample |
0ce1b118 | 31036 | long lseek (int fd, long offset, int flag); |
0ce1b118 CV |
31037 | @end smallexample |
31038 | ||
fc320d37 SL |
31039 | @item Request: |
31040 | @samp{Flseek,@var{fd},@var{offset},@var{flag}} | |
31041 | ||
31042 | @var{flag} is one of: | |
0ce1b118 CV |
31043 | |
31044 | @table @code | |
b383017d | 31045 | @item SEEK_SET |
fc320d37 | 31046 | The offset is set to @var{offset} bytes. |
0ce1b118 | 31047 | |
b383017d | 31048 | @item SEEK_CUR |
fc320d37 | 31049 | The offset is set to its current location plus @var{offset} |
0ce1b118 CV |
31050 | bytes. |
31051 | ||
b383017d | 31052 | @item SEEK_END |
fc320d37 | 31053 | The offset is set to the size of the file plus @var{offset} |
0ce1b118 CV |
31054 | bytes. |
31055 | @end table | |
31056 | ||
fc320d37 | 31057 | @item Return value: |
0ce1b118 CV |
31058 | On success, the resulting unsigned offset in bytes from |
31059 | the beginning of the file is returned. Otherwise, a | |
31060 | value of -1 is returned. | |
31061 | ||
fc320d37 | 31062 | @item Errors: |
0ce1b118 CV |
31063 | |
31064 | @table @code | |
b383017d | 31065 | @item EBADF |
fc320d37 | 31066 | @var{fd} is not a valid open file descriptor. |
0ce1b118 | 31067 | |
b383017d | 31068 | @item ESPIPE |
fc320d37 | 31069 | @var{fd} is associated with the @value{GDBN} console. |
0ce1b118 | 31070 | |
b383017d | 31071 | @item EINVAL |
fc320d37 | 31072 | @var{flag} is not a proper value. |
0ce1b118 | 31073 | |
b383017d | 31074 | @item EINTR |
0ce1b118 CV |
31075 | The call was interrupted by the user. |
31076 | @end table | |
31077 | ||
fc320d37 SL |
31078 | @end table |
31079 | ||
0ce1b118 CV |
31080 | @node rename |
31081 | @unnumberedsubsubsec rename | |
31082 | @cindex rename, file-i/o system call | |
31083 | ||
fc320d37 SL |
31084 | @table @asis |
31085 | @item Synopsis: | |
0ce1b118 | 31086 | @smallexample |
0ce1b118 | 31087 | int rename(const char *oldpath, const char *newpath); |
fc320d37 | 31088 | @end smallexample |
0ce1b118 | 31089 | |
fc320d37 SL |
31090 | @item Request: |
31091 | @samp{Frename,@var{oldpathptr}/@var{len},@var{newpathptr}/@var{len}} | |
0ce1b118 | 31092 | |
fc320d37 | 31093 | @item Return value: |
0ce1b118 CV |
31094 | On success, zero is returned. On error, -1 is returned. |
31095 | ||
fc320d37 | 31096 | @item Errors: |
0ce1b118 CV |
31097 | |
31098 | @table @code | |
b383017d | 31099 | @item EISDIR |
fc320d37 | 31100 | @var{newpath} is an existing directory, but @var{oldpath} is not a |
0ce1b118 CV |
31101 | directory. |
31102 | ||
b383017d | 31103 | @item EEXIST |
fc320d37 | 31104 | @var{newpath} is a non-empty directory. |
0ce1b118 | 31105 | |
b383017d | 31106 | @item EBUSY |
fc320d37 | 31107 | @var{oldpath} or @var{newpath} is a directory that is in use by some |
0ce1b118 CV |
31108 | process. |
31109 | ||
b383017d | 31110 | @item EINVAL |
0ce1b118 CV |
31111 | An attempt was made to make a directory a subdirectory |
31112 | of itself. | |
31113 | ||
b383017d | 31114 | @item ENOTDIR |
fc320d37 SL |
31115 | A component used as a directory in @var{oldpath} or new |
31116 | path is not a directory. Or @var{oldpath} is a directory | |
31117 | and @var{newpath} exists but is not a directory. | |
0ce1b118 | 31118 | |
b383017d | 31119 | @item EFAULT |
fc320d37 | 31120 | @var{oldpathptr} or @var{newpathptr} are invalid pointer values. |
0ce1b118 | 31121 | |
b383017d | 31122 | @item EACCES |
0ce1b118 CV |
31123 | No access to the file or the path of the file. |
31124 | ||
31125 | @item ENAMETOOLONG | |
b383017d | 31126 | |
fc320d37 | 31127 | @var{oldpath} or @var{newpath} was too long. |
0ce1b118 | 31128 | |
b383017d | 31129 | @item ENOENT |
fc320d37 | 31130 | A directory component in @var{oldpath} or @var{newpath} does not exist. |
0ce1b118 | 31131 | |
b383017d | 31132 | @item EROFS |
0ce1b118 CV |
31133 | The file is on a read-only filesystem. |
31134 | ||
b383017d | 31135 | @item ENOSPC |
0ce1b118 CV |
31136 | The device containing the file has no room for the new |
31137 | directory entry. | |
31138 | ||
b383017d | 31139 | @item EINTR |
0ce1b118 CV |
31140 | The call was interrupted by the user. |
31141 | @end table | |
31142 | ||
fc320d37 SL |
31143 | @end table |
31144 | ||
0ce1b118 CV |
31145 | @node unlink |
31146 | @unnumberedsubsubsec unlink | |
31147 | @cindex unlink, file-i/o system call | |
31148 | ||
fc320d37 SL |
31149 | @table @asis |
31150 | @item Synopsis: | |
0ce1b118 | 31151 | @smallexample |
0ce1b118 | 31152 | int unlink(const char *pathname); |
fc320d37 | 31153 | @end smallexample |
0ce1b118 | 31154 | |
fc320d37 SL |
31155 | @item Request: |
31156 | @samp{Funlink,@var{pathnameptr}/@var{len}} | |
0ce1b118 | 31157 | |
fc320d37 | 31158 | @item Return value: |
0ce1b118 CV |
31159 | On success, zero is returned. On error, -1 is returned. |
31160 | ||
fc320d37 | 31161 | @item Errors: |
0ce1b118 CV |
31162 | |
31163 | @table @code | |
b383017d | 31164 | @item EACCES |
0ce1b118 CV |
31165 | No access to the file or the path of the file. |
31166 | ||
b383017d | 31167 | @item EPERM |
0ce1b118 CV |
31168 | The system does not allow unlinking of directories. |
31169 | ||
b383017d | 31170 | @item EBUSY |
fc320d37 | 31171 | The file @var{pathname} cannot be unlinked because it's |
0ce1b118 CV |
31172 | being used by another process. |
31173 | ||
b383017d | 31174 | @item EFAULT |
fc320d37 | 31175 | @var{pathnameptr} is an invalid pointer value. |
0ce1b118 CV |
31176 | |
31177 | @item ENAMETOOLONG | |
fc320d37 | 31178 | @var{pathname} was too long. |
0ce1b118 | 31179 | |
b383017d | 31180 | @item ENOENT |
fc320d37 | 31181 | A directory component in @var{pathname} does not exist. |
0ce1b118 | 31182 | |
b383017d | 31183 | @item ENOTDIR |
0ce1b118 CV |
31184 | A component of the path is not a directory. |
31185 | ||
b383017d | 31186 | @item EROFS |
0ce1b118 CV |
31187 | The file is on a read-only filesystem. |
31188 | ||
b383017d | 31189 | @item EINTR |
0ce1b118 CV |
31190 | The call was interrupted by the user. |
31191 | @end table | |
31192 | ||
fc320d37 SL |
31193 | @end table |
31194 | ||
0ce1b118 CV |
31195 | @node stat/fstat |
31196 | @unnumberedsubsubsec stat/fstat | |
31197 | @cindex fstat, file-i/o system call | |
31198 | @cindex stat, file-i/o system call | |
31199 | ||
fc320d37 SL |
31200 | @table @asis |
31201 | @item Synopsis: | |
0ce1b118 | 31202 | @smallexample |
0ce1b118 CV |
31203 | int stat(const char *pathname, struct stat *buf); |
31204 | int fstat(int fd, struct stat *buf); | |
fc320d37 | 31205 | @end smallexample |
0ce1b118 | 31206 | |
fc320d37 SL |
31207 | @item Request: |
31208 | @samp{Fstat,@var{pathnameptr}/@var{len},@var{bufptr}}@* | |
31209 | @samp{Ffstat,@var{fd},@var{bufptr}} | |
0ce1b118 | 31210 | |
fc320d37 | 31211 | @item Return value: |
0ce1b118 CV |
31212 | On success, zero is returned. On error, -1 is returned. |
31213 | ||
fc320d37 | 31214 | @item Errors: |
0ce1b118 CV |
31215 | |
31216 | @table @code | |
b383017d | 31217 | @item EBADF |
fc320d37 | 31218 | @var{fd} is not a valid open file. |
0ce1b118 | 31219 | |
b383017d | 31220 | @item ENOENT |
fc320d37 | 31221 | A directory component in @var{pathname} does not exist or the |
0ce1b118 CV |
31222 | path is an empty string. |
31223 | ||
b383017d | 31224 | @item ENOTDIR |
0ce1b118 CV |
31225 | A component of the path is not a directory. |
31226 | ||
b383017d | 31227 | @item EFAULT |
fc320d37 | 31228 | @var{pathnameptr} is an invalid pointer value. |
0ce1b118 | 31229 | |
b383017d | 31230 | @item EACCES |
0ce1b118 CV |
31231 | No access to the file or the path of the file. |
31232 | ||
31233 | @item ENAMETOOLONG | |
fc320d37 | 31234 | @var{pathname} was too long. |
0ce1b118 | 31235 | |
b383017d | 31236 | @item EINTR |
0ce1b118 CV |
31237 | The call was interrupted by the user. |
31238 | @end table | |
31239 | ||
fc320d37 SL |
31240 | @end table |
31241 | ||
0ce1b118 CV |
31242 | @node gettimeofday |
31243 | @unnumberedsubsubsec gettimeofday | |
31244 | @cindex gettimeofday, file-i/o system call | |
31245 | ||
fc320d37 SL |
31246 | @table @asis |
31247 | @item Synopsis: | |
0ce1b118 | 31248 | @smallexample |
0ce1b118 | 31249 | int gettimeofday(struct timeval *tv, void *tz); |
fc320d37 | 31250 | @end smallexample |
0ce1b118 | 31251 | |
fc320d37 SL |
31252 | @item Request: |
31253 | @samp{Fgettimeofday,@var{tvptr},@var{tzptr}} | |
0ce1b118 | 31254 | |
fc320d37 | 31255 | @item Return value: |
0ce1b118 CV |
31256 | On success, 0 is returned, -1 otherwise. |
31257 | ||
fc320d37 | 31258 | @item Errors: |
0ce1b118 CV |
31259 | |
31260 | @table @code | |
b383017d | 31261 | @item EINVAL |
fc320d37 | 31262 | @var{tz} is a non-NULL pointer. |
0ce1b118 | 31263 | |
b383017d | 31264 | @item EFAULT |
fc320d37 SL |
31265 | @var{tvptr} and/or @var{tzptr} is an invalid pointer value. |
31266 | @end table | |
31267 | ||
0ce1b118 CV |
31268 | @end table |
31269 | ||
31270 | @node isatty | |
31271 | @unnumberedsubsubsec isatty | |
31272 | @cindex isatty, file-i/o system call | |
31273 | ||
fc320d37 SL |
31274 | @table @asis |
31275 | @item Synopsis: | |
0ce1b118 | 31276 | @smallexample |
0ce1b118 | 31277 | int isatty(int fd); |
fc320d37 | 31278 | @end smallexample |
0ce1b118 | 31279 | |
fc320d37 SL |
31280 | @item Request: |
31281 | @samp{Fisatty,@var{fd}} | |
0ce1b118 | 31282 | |
fc320d37 SL |
31283 | @item Return value: |
31284 | Returns 1 if @var{fd} refers to the @value{GDBN} console, 0 otherwise. | |
0ce1b118 | 31285 | |
fc320d37 | 31286 | @item Errors: |
0ce1b118 CV |
31287 | |
31288 | @table @code | |
b383017d | 31289 | @item EINTR |
0ce1b118 CV |
31290 | The call was interrupted by the user. |
31291 | @end table | |
31292 | ||
fc320d37 SL |
31293 | @end table |
31294 | ||
31295 | Note that the @code{isatty} call is treated as a special case: it returns | |
31296 | 1 to the target if the file descriptor is attached | |
31297 | to the @value{GDBN} console, 0 otherwise. Implementing through system calls | |
31298 | would require implementing @code{ioctl} and would be more complex than | |
31299 | needed. | |
31300 | ||
31301 | ||
0ce1b118 CV |
31302 | @node system |
31303 | @unnumberedsubsubsec system | |
31304 | @cindex system, file-i/o system call | |
31305 | ||
fc320d37 SL |
31306 | @table @asis |
31307 | @item Synopsis: | |
0ce1b118 | 31308 | @smallexample |
0ce1b118 | 31309 | int system(const char *command); |
fc320d37 | 31310 | @end smallexample |
0ce1b118 | 31311 | |
fc320d37 SL |
31312 | @item Request: |
31313 | @samp{Fsystem,@var{commandptr}/@var{len}} | |
0ce1b118 | 31314 | |
fc320d37 | 31315 | @item Return value: |
5600ea19 NS |
31316 | If @var{len} is zero, the return value indicates whether a shell is |
31317 | available. A zero return value indicates a shell is not available. | |
31318 | For non-zero @var{len}, the value returned is -1 on error and the | |
31319 | return status of the command otherwise. Only the exit status of the | |
31320 | command is returned, which is extracted from the host's @code{system} | |
31321 | return value by calling @code{WEXITSTATUS(retval)}. In case | |
31322 | @file{/bin/sh} could not be executed, 127 is returned. | |
0ce1b118 | 31323 | |
fc320d37 | 31324 | @item Errors: |
0ce1b118 CV |
31325 | |
31326 | @table @code | |
b383017d | 31327 | @item EINTR |
0ce1b118 CV |
31328 | The call was interrupted by the user. |
31329 | @end table | |
31330 | ||
fc320d37 SL |
31331 | @end table |
31332 | ||
31333 | @value{GDBN} takes over the full task of calling the necessary host calls | |
31334 | to perform the @code{system} call. The return value of @code{system} on | |
31335 | the host is simplified before it's returned | |
31336 | to the target. Any termination signal information from the child process | |
31337 | is discarded, and the return value consists | |
31338 | entirely of the exit status of the called command. | |
31339 | ||
31340 | Due to security concerns, the @code{system} call is by default refused | |
31341 | by @value{GDBN}. The user has to allow this call explicitly with the | |
31342 | @code{set remote system-call-allowed 1} command. | |
31343 | ||
31344 | @table @code | |
31345 | @item set remote system-call-allowed | |
31346 | @kindex set remote system-call-allowed | |
31347 | Control whether to allow the @code{system} calls in the File I/O | |
31348 | protocol for the remote target. The default is zero (disabled). | |
31349 | ||
31350 | @item show remote system-call-allowed | |
31351 | @kindex show remote system-call-allowed | |
31352 | Show whether the @code{system} calls are allowed in the File I/O | |
31353 | protocol. | |
31354 | @end table | |
31355 | ||
db2e3e2e BW |
31356 | @node Protocol-specific Representation of Datatypes |
31357 | @subsection Protocol-specific Representation of Datatypes | |
31358 | @cindex protocol-specific representation of datatypes, in file-i/o protocol | |
0ce1b118 CV |
31359 | |
31360 | @menu | |
79a6e687 BW |
31361 | * Integral Datatypes:: |
31362 | * Pointer Values:: | |
31363 | * Memory Transfer:: | |
0ce1b118 CV |
31364 | * struct stat:: |
31365 | * struct timeval:: | |
31366 | @end menu | |
31367 | ||
79a6e687 BW |
31368 | @node Integral Datatypes |
31369 | @unnumberedsubsubsec Integral Datatypes | |
0ce1b118 CV |
31370 | @cindex integral datatypes, in file-i/o protocol |
31371 | ||
fc320d37 SL |
31372 | The integral datatypes used in the system calls are @code{int}, |
31373 | @code{unsigned int}, @code{long}, @code{unsigned long}, | |
31374 | @code{mode_t}, and @code{time_t}. | |
0ce1b118 | 31375 | |
fc320d37 | 31376 | @code{int}, @code{unsigned int}, @code{mode_t} and @code{time_t} are |
0ce1b118 CV |
31377 | implemented as 32 bit values in this protocol. |
31378 | ||
fc320d37 | 31379 | @code{long} and @code{unsigned long} are implemented as 64 bit types. |
b383017d | 31380 | |
0ce1b118 CV |
31381 | @xref{Limits}, for corresponding MIN and MAX values (similar to those |
31382 | in @file{limits.h}) to allow range checking on host and target. | |
31383 | ||
31384 | @code{time_t} datatypes are defined as seconds since the Epoch. | |
31385 | ||
31386 | All integral datatypes transferred as part of a memory read or write of a | |
31387 | structured datatype e.g.@: a @code{struct stat} have to be given in big endian | |
31388 | byte order. | |
31389 | ||
79a6e687 BW |
31390 | @node Pointer Values |
31391 | @unnumberedsubsubsec Pointer Values | |
0ce1b118 CV |
31392 | @cindex pointer values, in file-i/o protocol |
31393 | ||
31394 | Pointers to target data are transmitted as they are. An exception | |
31395 | is made for pointers to buffers for which the length isn't | |
31396 | transmitted as part of the function call, namely strings. Strings | |
31397 | are transmitted as a pointer/length pair, both as hex values, e.g.@: | |
31398 | ||
31399 | @smallexample | |
31400 | @code{1aaf/12} | |
31401 | @end smallexample | |
31402 | ||
31403 | @noindent | |
31404 | which is a pointer to data of length 18 bytes at position 0x1aaf. | |
31405 | The length is defined as the full string length in bytes, including | |
fc320d37 SL |
31406 | the trailing null byte. For example, the string @code{"hello world"} |
31407 | at address 0x123456 is transmitted as | |
0ce1b118 CV |
31408 | |
31409 | @smallexample | |
fc320d37 | 31410 | @code{123456/d} |
0ce1b118 CV |
31411 | @end smallexample |
31412 | ||
79a6e687 BW |
31413 | @node Memory Transfer |
31414 | @unnumberedsubsubsec Memory Transfer | |
fc320d37 SL |
31415 | @cindex memory transfer, in file-i/o protocol |
31416 | ||
31417 | Structured data which is transferred using a memory read or write (for | |
db2e3e2e | 31418 | example, a @code{struct stat}) is expected to be in a protocol-specific format |
fc320d37 SL |
31419 | with all scalar multibyte datatypes being big endian. Translation to |
31420 | this representation needs to be done both by the target before the @code{F} | |
31421 | packet is sent, and by @value{GDBN} before | |
31422 | it transfers memory to the target. Transferred pointers to structured | |
31423 | data should point to the already-coerced data at any time. | |
0ce1b118 | 31424 | |
0ce1b118 CV |
31425 | |
31426 | @node struct stat | |
31427 | @unnumberedsubsubsec struct stat | |
31428 | @cindex struct stat, in file-i/o protocol | |
31429 | ||
fc320d37 SL |
31430 | The buffer of type @code{struct stat} used by the target and @value{GDBN} |
31431 | is defined as follows: | |
0ce1b118 CV |
31432 | |
31433 | @smallexample | |
31434 | struct stat @{ | |
31435 | unsigned int st_dev; /* device */ | |
31436 | unsigned int st_ino; /* inode */ | |
31437 | mode_t st_mode; /* protection */ | |
31438 | unsigned int st_nlink; /* number of hard links */ | |
31439 | unsigned int st_uid; /* user ID of owner */ | |
31440 | unsigned int st_gid; /* group ID of owner */ | |
31441 | unsigned int st_rdev; /* device type (if inode device) */ | |
31442 | unsigned long st_size; /* total size, in bytes */ | |
31443 | unsigned long st_blksize; /* blocksize for filesystem I/O */ | |
31444 | unsigned long st_blocks; /* number of blocks allocated */ | |
31445 | time_t st_atime; /* time of last access */ | |
31446 | time_t st_mtime; /* time of last modification */ | |
31447 | time_t st_ctime; /* time of last change */ | |
31448 | @}; | |
31449 | @end smallexample | |
31450 | ||
fc320d37 | 31451 | The integral datatypes conform to the definitions given in the |
79a6e687 | 31452 | appropriate section (see @ref{Integral Datatypes}, for details) so this |
0ce1b118 CV |
31453 | structure is of size 64 bytes. |
31454 | ||
31455 | The values of several fields have a restricted meaning and/or | |
31456 | range of values. | |
31457 | ||
fc320d37 | 31458 | @table @code |
0ce1b118 | 31459 | |
fc320d37 SL |
31460 | @item st_dev |
31461 | A value of 0 represents a file, 1 the console. | |
0ce1b118 | 31462 | |
fc320d37 SL |
31463 | @item st_ino |
31464 | No valid meaning for the target. Transmitted unchanged. | |
0ce1b118 | 31465 | |
fc320d37 SL |
31466 | @item st_mode |
31467 | Valid mode bits are described in @ref{Constants}. Any other | |
31468 | bits have currently no meaning for the target. | |
0ce1b118 | 31469 | |
fc320d37 SL |
31470 | @item st_uid |
31471 | @itemx st_gid | |
31472 | @itemx st_rdev | |
31473 | No valid meaning for the target. Transmitted unchanged. | |
0ce1b118 | 31474 | |
fc320d37 SL |
31475 | @item st_atime |
31476 | @itemx st_mtime | |
31477 | @itemx st_ctime | |
31478 | These values have a host and file system dependent | |
31479 | accuracy. Especially on Windows hosts, the file system may not | |
31480 | support exact timing values. | |
31481 | @end table | |
0ce1b118 | 31482 | |
fc320d37 SL |
31483 | The target gets a @code{struct stat} of the above representation and is |
31484 | responsible for coercing it to the target representation before | |
0ce1b118 CV |
31485 | continuing. |
31486 | ||
fc320d37 SL |
31487 | Note that due to size differences between the host, target, and protocol |
31488 | representations of @code{struct stat} members, these members could eventually | |
0ce1b118 CV |
31489 | get truncated on the target. |
31490 | ||
31491 | @node struct timeval | |
31492 | @unnumberedsubsubsec struct timeval | |
31493 | @cindex struct timeval, in file-i/o protocol | |
31494 | ||
fc320d37 | 31495 | The buffer of type @code{struct timeval} used by the File-I/O protocol |
0ce1b118 CV |
31496 | is defined as follows: |
31497 | ||
31498 | @smallexample | |
b383017d | 31499 | struct timeval @{ |
0ce1b118 CV |
31500 | time_t tv_sec; /* second */ |
31501 | long tv_usec; /* microsecond */ | |
31502 | @}; | |
31503 | @end smallexample | |
31504 | ||
fc320d37 | 31505 | The integral datatypes conform to the definitions given in the |
79a6e687 | 31506 | appropriate section (see @ref{Integral Datatypes}, for details) so this |
0ce1b118 CV |
31507 | structure is of size 8 bytes. |
31508 | ||
31509 | @node Constants | |
31510 | @subsection Constants | |
31511 | @cindex constants, in file-i/o protocol | |
31512 | ||
31513 | The following values are used for the constants inside of the | |
fc320d37 | 31514 | protocol. @value{GDBN} and target are responsible for translating these |
0ce1b118 CV |
31515 | values before and after the call as needed. |
31516 | ||
31517 | @menu | |
79a6e687 BW |
31518 | * Open Flags:: |
31519 | * mode_t Values:: | |
31520 | * Errno Values:: | |
31521 | * Lseek Flags:: | |
0ce1b118 CV |
31522 | * Limits:: |
31523 | @end menu | |
31524 | ||
79a6e687 BW |
31525 | @node Open Flags |
31526 | @unnumberedsubsubsec Open Flags | |
0ce1b118 CV |
31527 | @cindex open flags, in file-i/o protocol |
31528 | ||
31529 | All values are given in hexadecimal representation. | |
31530 | ||
31531 | @smallexample | |
31532 | O_RDONLY 0x0 | |
31533 | O_WRONLY 0x1 | |
31534 | O_RDWR 0x2 | |
31535 | O_APPEND 0x8 | |
31536 | O_CREAT 0x200 | |
31537 | O_TRUNC 0x400 | |
31538 | O_EXCL 0x800 | |
31539 | @end smallexample | |
31540 | ||
79a6e687 BW |
31541 | @node mode_t Values |
31542 | @unnumberedsubsubsec mode_t Values | |
0ce1b118 CV |
31543 | @cindex mode_t values, in file-i/o protocol |
31544 | ||
31545 | All values are given in octal representation. | |
31546 | ||
31547 | @smallexample | |
31548 | S_IFREG 0100000 | |
31549 | S_IFDIR 040000 | |
31550 | S_IRUSR 0400 | |
31551 | S_IWUSR 0200 | |
31552 | S_IXUSR 0100 | |
31553 | S_IRGRP 040 | |
31554 | S_IWGRP 020 | |
31555 | S_IXGRP 010 | |
31556 | S_IROTH 04 | |
31557 | S_IWOTH 02 | |
31558 | S_IXOTH 01 | |
31559 | @end smallexample | |
31560 | ||
79a6e687 BW |
31561 | @node Errno Values |
31562 | @unnumberedsubsubsec Errno Values | |
0ce1b118 CV |
31563 | @cindex errno values, in file-i/o protocol |
31564 | ||
31565 | All values are given in decimal representation. | |
31566 | ||
31567 | @smallexample | |
31568 | EPERM 1 | |
31569 | ENOENT 2 | |
31570 | EINTR 4 | |
31571 | EBADF 9 | |
31572 | EACCES 13 | |
31573 | EFAULT 14 | |
31574 | EBUSY 16 | |
31575 | EEXIST 17 | |
31576 | ENODEV 19 | |
31577 | ENOTDIR 20 | |
31578 | EISDIR 21 | |
31579 | EINVAL 22 | |
31580 | ENFILE 23 | |
31581 | EMFILE 24 | |
31582 | EFBIG 27 | |
31583 | ENOSPC 28 | |
31584 | ESPIPE 29 | |
31585 | EROFS 30 | |
31586 | ENAMETOOLONG 91 | |
31587 | EUNKNOWN 9999 | |
31588 | @end smallexample | |
31589 | ||
fc320d37 | 31590 | @code{EUNKNOWN} is used as a fallback error value if a host system returns |
0ce1b118 CV |
31591 | any error value not in the list of supported error numbers. |
31592 | ||
79a6e687 BW |
31593 | @node Lseek Flags |
31594 | @unnumberedsubsubsec Lseek Flags | |
0ce1b118 CV |
31595 | @cindex lseek flags, in file-i/o protocol |
31596 | ||
31597 | @smallexample | |
31598 | SEEK_SET 0 | |
31599 | SEEK_CUR 1 | |
31600 | SEEK_END 2 | |
31601 | @end smallexample | |
31602 | ||
31603 | @node Limits | |
31604 | @unnumberedsubsubsec Limits | |
31605 | @cindex limits, in file-i/o protocol | |
31606 | ||
31607 | All values are given in decimal representation. | |
31608 | ||
31609 | @smallexample | |
31610 | INT_MIN -2147483648 | |
31611 | INT_MAX 2147483647 | |
31612 | UINT_MAX 4294967295 | |
31613 | LONG_MIN -9223372036854775808 | |
31614 | LONG_MAX 9223372036854775807 | |
31615 | ULONG_MAX 18446744073709551615 | |
31616 | @end smallexample | |
31617 | ||
31618 | @node File-I/O Examples | |
31619 | @subsection File-I/O Examples | |
31620 | @cindex file-i/o examples | |
31621 | ||
31622 | Example sequence of a write call, file descriptor 3, buffer is at target | |
31623 | address 0x1234, 6 bytes should be written: | |
31624 | ||
31625 | @smallexample | |
31626 | <- @code{Fwrite,3,1234,6} | |
31627 | @emph{request memory read from target} | |
31628 | -> @code{m1234,6} | |
31629 | <- XXXXXX | |
31630 | @emph{return "6 bytes written"} | |
31631 | -> @code{F6} | |
31632 | @end smallexample | |
31633 | ||
31634 | Example sequence of a read call, file descriptor 3, buffer is at target | |
31635 | address 0x1234, 6 bytes should be read: | |
31636 | ||
31637 | @smallexample | |
31638 | <- @code{Fread,3,1234,6} | |
31639 | @emph{request memory write to target} | |
31640 | -> @code{X1234,6:XXXXXX} | |
31641 | @emph{return "6 bytes read"} | |
31642 | -> @code{F6} | |
31643 | @end smallexample | |
31644 | ||
31645 | Example sequence of a read call, call fails on the host due to invalid | |
fc320d37 | 31646 | file descriptor (@code{EBADF}): |
0ce1b118 CV |
31647 | |
31648 | @smallexample | |
31649 | <- @code{Fread,3,1234,6} | |
31650 | -> @code{F-1,9} | |
31651 | @end smallexample | |
31652 | ||
c8aa23ab | 31653 | Example sequence of a read call, user presses @kbd{Ctrl-c} before syscall on |
0ce1b118 CV |
31654 | host is called: |
31655 | ||
31656 | @smallexample | |
31657 | <- @code{Fread,3,1234,6} | |
31658 | -> @code{F-1,4,C} | |
31659 | <- @code{T02} | |
31660 | @end smallexample | |
31661 | ||
c8aa23ab | 31662 | Example sequence of a read call, user presses @kbd{Ctrl-c} after syscall on |
0ce1b118 CV |
31663 | host is called: |
31664 | ||
31665 | @smallexample | |
31666 | <- @code{Fread,3,1234,6} | |
31667 | -> @code{X1234,6:XXXXXX} | |
31668 | <- @code{T02} | |
31669 | @end smallexample | |
31670 | ||
cfa9d6d9 DJ |
31671 | @node Library List Format |
31672 | @section Library List Format | |
31673 | @cindex library list format, remote protocol | |
31674 | ||
31675 | On some platforms, a dynamic loader (e.g.@: @file{ld.so}) runs in the | |
31676 | same process as your application to manage libraries. In this case, | |
31677 | @value{GDBN} can use the loader's symbol table and normal memory | |
31678 | operations to maintain a list of shared libraries. On other | |
31679 | platforms, the operating system manages loaded libraries. | |
31680 | @value{GDBN} can not retrieve the list of currently loaded libraries | |
31681 | through memory operations, so it uses the @samp{qXfer:libraries:read} | |
31682 | packet (@pxref{qXfer library list read}) instead. The remote stub | |
31683 | queries the target's operating system and reports which libraries | |
31684 | are loaded. | |
31685 | ||
31686 | The @samp{qXfer:libraries:read} packet returns an XML document which | |
31687 | lists loaded libraries and their offsets. Each library has an | |
1fddbabb PA |
31688 | associated name and one or more segment or section base addresses, |
31689 | which report where the library was loaded in memory. | |
31690 | ||
31691 | For the common case of libraries that are fully linked binaries, the | |
31692 | library should have a list of segments. If the target supports | |
31693 | dynamic linking of a relocatable object file, its library XML element | |
31694 | should instead include a list of allocated sections. The segment or | |
31695 | section bases are start addresses, not relocation offsets; they do not | |
31696 | depend on the library's link-time base addresses. | |
cfa9d6d9 | 31697 | |
9cceb671 DJ |
31698 | @value{GDBN} must be linked with the Expat library to support XML |
31699 | library lists. @xref{Expat}. | |
31700 | ||
cfa9d6d9 DJ |
31701 | A simple memory map, with one loaded library relocated by a single |
31702 | offset, looks like this: | |
31703 | ||
31704 | @smallexample | |
31705 | <library-list> | |
31706 | <library name="/lib/libc.so.6"> | |
31707 | <segment address="0x10000000"/> | |
31708 | </library> | |
31709 | </library-list> | |
31710 | @end smallexample | |
31711 | ||
1fddbabb PA |
31712 | Another simple memory map, with one loaded library with three |
31713 | allocated sections (.text, .data, .bss), looks like this: | |
31714 | ||
31715 | @smallexample | |
31716 | <library-list> | |
31717 | <library name="sharedlib.o"> | |
31718 | <section address="0x10000000"/> | |
31719 | <section address="0x20000000"/> | |
31720 | <section address="0x30000000"/> | |
31721 | </library> | |
31722 | </library-list> | |
31723 | @end smallexample | |
31724 | ||
cfa9d6d9 DJ |
31725 | The format of a library list is described by this DTD: |
31726 | ||
31727 | @smallexample | |
31728 | <!-- library-list: Root element with versioning --> | |
31729 | <!ELEMENT library-list (library)*> | |
31730 | <!ATTLIST library-list version CDATA #FIXED "1.0"> | |
1fddbabb | 31731 | <!ELEMENT library (segment*, section*)> |
cfa9d6d9 DJ |
31732 | <!ATTLIST library name CDATA #REQUIRED> |
31733 | <!ELEMENT segment EMPTY> | |
31734 | <!ATTLIST segment address CDATA #REQUIRED> | |
1fddbabb PA |
31735 | <!ELEMENT section EMPTY> |
31736 | <!ATTLIST section address CDATA #REQUIRED> | |
cfa9d6d9 DJ |
31737 | @end smallexample |
31738 | ||
1fddbabb PA |
31739 | In addition, segments and section descriptors cannot be mixed within a |
31740 | single library element, and you must supply at least one segment or | |
31741 | section for each library. | |
31742 | ||
79a6e687 BW |
31743 | @node Memory Map Format |
31744 | @section Memory Map Format | |
68437a39 DJ |
31745 | @cindex memory map format |
31746 | ||
31747 | To be able to write into flash memory, @value{GDBN} needs to obtain a | |
31748 | memory map from the target. This section describes the format of the | |
31749 | memory map. | |
31750 | ||
31751 | The memory map is obtained using the @samp{qXfer:memory-map:read} | |
31752 | (@pxref{qXfer memory map read}) packet and is an XML document that | |
9cceb671 DJ |
31753 | lists memory regions. |
31754 | ||
31755 | @value{GDBN} must be linked with the Expat library to support XML | |
31756 | memory maps. @xref{Expat}. | |
31757 | ||
31758 | The top-level structure of the document is shown below: | |
68437a39 DJ |
31759 | |
31760 | @smallexample | |
31761 | <?xml version="1.0"?> | |
31762 | <!DOCTYPE memory-map | |
31763 | PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN" | |
31764 | "http://sourceware.org/gdb/gdb-memory-map.dtd"> | |
31765 | <memory-map> | |
31766 | region... | |
31767 | </memory-map> | |
31768 | @end smallexample | |
31769 | ||
31770 | Each region can be either: | |
31771 | ||
31772 | @itemize | |
31773 | ||
31774 | @item | |
31775 | A region of RAM starting at @var{addr} and extending for @var{length} | |
31776 | bytes from there: | |
31777 | ||
31778 | @smallexample | |
31779 | <memory type="ram" start="@var{addr}" length="@var{length}"/> | |
31780 | @end smallexample | |
31781 | ||
31782 | ||
31783 | @item | |
31784 | A region of read-only memory: | |
31785 | ||
31786 | @smallexample | |
31787 | <memory type="rom" start="@var{addr}" length="@var{length}"/> | |
31788 | @end smallexample | |
31789 | ||
31790 | ||
31791 | @item | |
31792 | A region of flash memory, with erasure blocks @var{blocksize} | |
31793 | bytes in length: | |
31794 | ||
31795 | @smallexample | |
31796 | <memory type="flash" start="@var{addr}" length="@var{length}"> | |
31797 | <property name="blocksize">@var{blocksize}</property> | |
31798 | </memory> | |
31799 | @end smallexample | |
31800 | ||
31801 | @end itemize | |
31802 | ||
31803 | Regions must not overlap. @value{GDBN} assumes that areas of memory not covered | |
31804 | by the memory map are RAM, and uses the ordinary @samp{M} and @samp{X} | |
31805 | packets to write to addresses in such ranges. | |
31806 | ||
31807 | The formal DTD for memory map format is given below: | |
31808 | ||
31809 | @smallexample | |
31810 | <!-- ................................................... --> | |
31811 | <!-- Memory Map XML DTD ................................ --> | |
31812 | <!-- File: memory-map.dtd .............................. --> | |
31813 | <!-- .................................... .............. --> | |
31814 | <!-- memory-map.dtd --> | |
31815 | <!-- memory-map: Root element with versioning --> | |
31816 | <!ELEMENT memory-map (memory | property)> | |
31817 | <!ATTLIST memory-map version CDATA #FIXED "1.0.0"> | |
31818 | <!ELEMENT memory (property)> | |
31819 | <!-- memory: Specifies a memory region, | |
31820 | and its type, or device. --> | |
31821 | <!ATTLIST memory type CDATA #REQUIRED | |
31822 | start CDATA #REQUIRED | |
31823 | length CDATA #REQUIRED | |
31824 | device CDATA #IMPLIED> | |
31825 | <!-- property: Generic attribute tag --> | |
31826 | <!ELEMENT property (#PCDATA | property)*> | |
31827 | <!ATTLIST property name CDATA #REQUIRED> | |
31828 | @end smallexample | |
31829 | ||
f418dd93 DJ |
31830 | @include agentexpr.texi |
31831 | ||
23181151 DJ |
31832 | @node Target Descriptions |
31833 | @appendix Target Descriptions | |
31834 | @cindex target descriptions | |
31835 | ||
31836 | @strong{Warning:} target descriptions are still under active development, | |
31837 | and the contents and format may change between @value{GDBN} releases. | |
31838 | The format is expected to stabilize in the future. | |
31839 | ||
31840 | One of the challenges of using @value{GDBN} to debug embedded systems | |
31841 | is that there are so many minor variants of each processor | |
31842 | architecture in use. It is common practice for vendors to start with | |
31843 | a standard processor core --- ARM, PowerPC, or MIPS, for example --- | |
31844 | and then make changes to adapt it to a particular market niche. Some | |
31845 | architectures have hundreds of variants, available from dozens of | |
31846 | vendors. This leads to a number of problems: | |
31847 | ||
31848 | @itemize @bullet | |
31849 | @item | |
31850 | With so many different customized processors, it is difficult for | |
31851 | the @value{GDBN} maintainers to keep up with the changes. | |
31852 | @item | |
31853 | Since individual variants may have short lifetimes or limited | |
31854 | audiences, it may not be worthwhile to carry information about every | |
31855 | variant in the @value{GDBN} source tree. | |
31856 | @item | |
31857 | When @value{GDBN} does support the architecture of the embedded system | |
31858 | at hand, the task of finding the correct architecture name to give the | |
31859 | @command{set architecture} command can be error-prone. | |
31860 | @end itemize | |
31861 | ||
31862 | To address these problems, the @value{GDBN} remote protocol allows a | |
31863 | target system to not only identify itself to @value{GDBN}, but to | |
31864 | actually describe its own features. This lets @value{GDBN} support | |
31865 | processor variants it has never seen before --- to the extent that the | |
31866 | descriptions are accurate, and that @value{GDBN} understands them. | |
31867 | ||
9cceb671 DJ |
31868 | @value{GDBN} must be linked with the Expat library to support XML |
31869 | target descriptions. @xref{Expat}. | |
123dc839 | 31870 | |
23181151 DJ |
31871 | @menu |
31872 | * Retrieving Descriptions:: How descriptions are fetched from a target. | |
31873 | * Target Description Format:: The contents of a target description. | |
123dc839 DJ |
31874 | * Predefined Target Types:: Standard types available for target |
31875 | descriptions. | |
31876 | * Standard Target Features:: Features @value{GDBN} knows about. | |
23181151 DJ |
31877 | @end menu |
31878 | ||
31879 | @node Retrieving Descriptions | |
31880 | @section Retrieving Descriptions | |
31881 | ||
31882 | Target descriptions can be read from the target automatically, or | |
31883 | specified by the user manually. The default behavior is to read the | |
31884 | description from the target. @value{GDBN} retrieves it via the remote | |
31885 | protocol using @samp{qXfer} requests (@pxref{General Query Packets, | |
31886 | qXfer}). The @var{annex} in the @samp{qXfer} packet will be | |
31887 | @samp{target.xml}. The contents of the @samp{target.xml} annex are an | |
31888 | XML document, of the form described in @ref{Target Description | |
31889 | Format}. | |
31890 | ||
31891 | Alternatively, you can specify a file to read for the target description. | |
31892 | If a file is set, the target will not be queried. The commands to | |
31893 | specify a file are: | |
31894 | ||
31895 | @table @code | |
31896 | @cindex set tdesc filename | |
31897 | @item set tdesc filename @var{path} | |
31898 | Read the target description from @var{path}. | |
31899 | ||
31900 | @cindex unset tdesc filename | |
31901 | @item unset tdesc filename | |
31902 | Do not read the XML target description from a file. @value{GDBN} | |
31903 | will use the description supplied by the current target. | |
31904 | ||
31905 | @cindex show tdesc filename | |
31906 | @item show tdesc filename | |
31907 | Show the filename to read for a target description, if any. | |
31908 | @end table | |
31909 | ||
31910 | ||
31911 | @node Target Description Format | |
31912 | @section Target Description Format | |
31913 | @cindex target descriptions, XML format | |
31914 | ||
31915 | A target description annex is an @uref{http://www.w3.org/XML/, XML} | |
31916 | document which complies with the Document Type Definition provided in | |
31917 | the @value{GDBN} sources in @file{gdb/features/gdb-target.dtd}. This | |
31918 | means you can use generally available tools like @command{xmllint} to | |
31919 | check that your feature descriptions are well-formed and valid. | |
31920 | However, to help people unfamiliar with XML write descriptions for | |
31921 | their targets, we also describe the grammar here. | |
31922 | ||
123dc839 DJ |
31923 | Target descriptions can identify the architecture of the remote target |
31924 | and (for some architectures) provide information about custom register | |
08d16641 PA |
31925 | sets. They can also identify the OS ABI of the remote target. |
31926 | @value{GDBN} can use this information to autoconfigure for your | |
123dc839 | 31927 | target, or to warn you if you connect to an unsupported target. |
23181151 DJ |
31928 | |
31929 | Here is a simple target description: | |
31930 | ||
123dc839 | 31931 | @smallexample |
1780a0ed | 31932 | <target version="1.0"> |
23181151 DJ |
31933 | <architecture>i386:x86-64</architecture> |
31934 | </target> | |
123dc839 | 31935 | @end smallexample |
23181151 DJ |
31936 | |
31937 | @noindent | |
31938 | This minimal description only says that the target uses | |
31939 | the x86-64 architecture. | |
31940 | ||
123dc839 DJ |
31941 | A target description has the following overall form, with [ ] marking |
31942 | optional elements and @dots{} marking repeatable elements. The elements | |
31943 | are explained further below. | |
23181151 | 31944 | |
123dc839 | 31945 | @smallexample |
23181151 DJ |
31946 | <?xml version="1.0"?> |
31947 | <!DOCTYPE target SYSTEM "gdb-target.dtd"> | |
1780a0ed | 31948 | <target version="1.0"> |
123dc839 | 31949 | @r{[}@var{architecture}@r{]} |
08d16641 | 31950 | @r{[}@var{osabi}@r{]} |
e35359c5 | 31951 | @r{[}@var{compatible}@r{]} |
123dc839 | 31952 | @r{[}@var{feature}@dots{}@r{]} |
23181151 | 31953 | </target> |
123dc839 | 31954 | @end smallexample |
23181151 DJ |
31955 | |
31956 | @noindent | |
31957 | The description is generally insensitive to whitespace and line | |
31958 | breaks, under the usual common-sense rules. The XML version | |
31959 | declaration and document type declaration can generally be omitted | |
31960 | (@value{GDBN} does not require them), but specifying them may be | |
1780a0ed DJ |
31961 | useful for XML validation tools. The @samp{version} attribute for |
31962 | @samp{<target>} may also be omitted, but we recommend | |
31963 | including it; if future versions of @value{GDBN} use an incompatible | |
31964 | revision of @file{gdb-target.dtd}, they will detect and report | |
31965 | the version mismatch. | |
23181151 | 31966 | |
108546a0 DJ |
31967 | @subsection Inclusion |
31968 | @cindex target descriptions, inclusion | |
31969 | @cindex XInclude | |
31970 | @ifnotinfo | |
31971 | @cindex <xi:include> | |
31972 | @end ifnotinfo | |
31973 | ||
31974 | It can sometimes be valuable to split a target description up into | |
31975 | several different annexes, either for organizational purposes, or to | |
31976 | share files between different possible target descriptions. You can | |
31977 | divide a description into multiple files by replacing any element of | |
31978 | the target description with an inclusion directive of the form: | |
31979 | ||
123dc839 | 31980 | @smallexample |
108546a0 | 31981 | <xi:include href="@var{document}"/> |
123dc839 | 31982 | @end smallexample |
108546a0 DJ |
31983 | |
31984 | @noindent | |
31985 | When @value{GDBN} encounters an element of this form, it will retrieve | |
31986 | the named XML @var{document}, and replace the inclusion directive with | |
31987 | the contents of that document. If the current description was read | |
31988 | using @samp{qXfer}, then so will be the included document; | |
31989 | @var{document} will be interpreted as the name of an annex. If the | |
31990 | current description was read from a file, @value{GDBN} will look for | |
31991 | @var{document} as a file in the same directory where it found the | |
31992 | original description. | |
31993 | ||
123dc839 DJ |
31994 | @subsection Architecture |
31995 | @cindex <architecture> | |
31996 | ||
31997 | An @samp{<architecture>} element has this form: | |
31998 | ||
31999 | @smallexample | |
32000 | <architecture>@var{arch}</architecture> | |
32001 | @end smallexample | |
32002 | ||
e35359c5 UW |
32003 | @var{arch} is one of the architectures from the set accepted by |
32004 | @code{set architecture} (@pxref{Targets, ,Specifying a Debugging Target}). | |
123dc839 | 32005 | |
08d16641 PA |
32006 | @subsection OS ABI |
32007 | @cindex @code{<osabi>} | |
32008 | ||
32009 | This optional field was introduced in @value{GDBN} version 7.0. | |
32010 | Previous versions of @value{GDBN} ignore it. | |
32011 | ||
32012 | An @samp{<osabi>} element has this form: | |
32013 | ||
32014 | @smallexample | |
32015 | <osabi>@var{abi-name}</osabi> | |
32016 | @end smallexample | |
32017 | ||
32018 | @var{abi-name} is an OS ABI name from the same selection accepted by | |
32019 | @w{@code{set osabi}} (@pxref{ABI, ,Configuring the Current ABI}). | |
32020 | ||
e35359c5 UW |
32021 | @subsection Compatible Architecture |
32022 | @cindex @code{<compatible>} | |
32023 | ||
32024 | This optional field was introduced in @value{GDBN} version 7.0. | |
32025 | Previous versions of @value{GDBN} ignore it. | |
32026 | ||
32027 | A @samp{<compatible>} element has this form: | |
32028 | ||
32029 | @smallexample | |
32030 | <compatible>@var{arch}</compatible> | |
32031 | @end smallexample | |
32032 | ||
32033 | @var{arch} is one of the architectures from the set accepted by | |
32034 | @code{set architecture} (@pxref{Targets, ,Specifying a Debugging Target}). | |
32035 | ||
32036 | A @samp{<compatible>} element is used to specify that the target | |
32037 | is able to run binaries in some other than the main target architecture | |
32038 | given by the @samp{<architecture>} element. For example, on the | |
32039 | Cell Broadband Engine, the main architecture is @code{powerpc:common} | |
32040 | or @code{powerpc:common64}, but the system is able to run binaries | |
32041 | in the @code{spu} architecture as well. The way to describe this | |
32042 | capability with @samp{<compatible>} is as follows: | |
32043 | ||
32044 | @smallexample | |
32045 | <architecture>powerpc:common</architecture> | |
32046 | <compatible>spu</compatible> | |
32047 | @end smallexample | |
32048 | ||
123dc839 DJ |
32049 | @subsection Features |
32050 | @cindex <feature> | |
32051 | ||
32052 | Each @samp{<feature>} describes some logical portion of the target | |
32053 | system. Features are currently used to describe available CPU | |
32054 | registers and the types of their contents. A @samp{<feature>} element | |
32055 | has this form: | |
32056 | ||
32057 | @smallexample | |
32058 | <feature name="@var{name}"> | |
32059 | @r{[}@var{type}@dots{}@r{]} | |
32060 | @var{reg}@dots{} | |
32061 | </feature> | |
32062 | @end smallexample | |
32063 | ||
32064 | @noindent | |
32065 | Each feature's name should be unique within the description. The name | |
32066 | of a feature does not matter unless @value{GDBN} has some special | |
32067 | knowledge of the contents of that feature; if it does, the feature | |
32068 | should have its standard name. @xref{Standard Target Features}. | |
32069 | ||
32070 | @subsection Types | |
32071 | ||
32072 | Any register's value is a collection of bits which @value{GDBN} must | |
32073 | interpret. The default interpretation is a two's complement integer, | |
32074 | but other types can be requested by name in the register description. | |
32075 | Some predefined types are provided by @value{GDBN} (@pxref{Predefined | |
32076 | Target Types}), and the description can define additional composite types. | |
32077 | ||
32078 | Each type element must have an @samp{id} attribute, which gives | |
32079 | a unique (within the containing @samp{<feature>}) name to the type. | |
32080 | Types must be defined before they are used. | |
32081 | ||
32082 | @cindex <vector> | |
32083 | Some targets offer vector registers, which can be treated as arrays | |
32084 | of scalar elements. These types are written as @samp{<vector>} elements, | |
32085 | specifying the array element type, @var{type}, and the number of elements, | |
32086 | @var{count}: | |
32087 | ||
32088 | @smallexample | |
32089 | <vector id="@var{id}" type="@var{type}" count="@var{count}"/> | |
32090 | @end smallexample | |
32091 | ||
32092 | @cindex <union> | |
32093 | If a register's value is usefully viewed in multiple ways, define it | |
32094 | with a union type containing the useful representations. The | |
32095 | @samp{<union>} element contains one or more @samp{<field>} elements, | |
32096 | each of which has a @var{name} and a @var{type}: | |
32097 | ||
32098 | @smallexample | |
32099 | <union id="@var{id}"> | |
32100 | <field name="@var{name}" type="@var{type}"/> | |
32101 | @dots{} | |
32102 | </union> | |
32103 | @end smallexample | |
32104 | ||
32105 | @subsection Registers | |
32106 | @cindex <reg> | |
32107 | ||
32108 | Each register is represented as an element with this form: | |
32109 | ||
32110 | @smallexample | |
32111 | <reg name="@var{name}" | |
32112 | bitsize="@var{size}" | |
32113 | @r{[}regnum="@var{num}"@r{]} | |
32114 | @r{[}save-restore="@var{save-restore}"@r{]} | |
32115 | @r{[}type="@var{type}"@r{]} | |
32116 | @r{[}group="@var{group}"@r{]}/> | |
32117 | @end smallexample | |
32118 | ||
32119 | @noindent | |
32120 | The components are as follows: | |
32121 | ||
32122 | @table @var | |
32123 | ||
32124 | @item name | |
32125 | The register's name; it must be unique within the target description. | |
32126 | ||
32127 | @item bitsize | |
32128 | The register's size, in bits. | |
32129 | ||
32130 | @item regnum | |
32131 | The register's number. If omitted, a register's number is one greater | |
32132 | than that of the previous register (either in the current feature or in | |
32133 | a preceeding feature); the first register in the target description | |
32134 | defaults to zero. This register number is used to read or write | |
32135 | the register; e.g.@: it is used in the remote @code{p} and @code{P} | |
32136 | packets, and registers appear in the @code{g} and @code{G} packets | |
32137 | in order of increasing register number. | |
32138 | ||
32139 | @item save-restore | |
32140 | Whether the register should be preserved across inferior function | |
32141 | calls; this must be either @code{yes} or @code{no}. The default is | |
32142 | @code{yes}, which is appropriate for most registers except for | |
32143 | some system control registers; this is not related to the target's | |
32144 | ABI. | |
32145 | ||
32146 | @item type | |
32147 | The type of the register. @var{type} may be a predefined type, a type | |
32148 | defined in the current feature, or one of the special types @code{int} | |
32149 | and @code{float}. @code{int} is an integer type of the correct size | |
32150 | for @var{bitsize}, and @code{float} is a floating point type (in the | |
32151 | architecture's normal floating point format) of the correct size for | |
32152 | @var{bitsize}. The default is @code{int}. | |
32153 | ||
32154 | @item group | |
32155 | The register group to which this register belongs. @var{group} must | |
32156 | be either @code{general}, @code{float}, or @code{vector}. If no | |
32157 | @var{group} is specified, @value{GDBN} will not display the register | |
32158 | in @code{info registers}. | |
32159 | ||
32160 | @end table | |
32161 | ||
32162 | @node Predefined Target Types | |
32163 | @section Predefined Target Types | |
32164 | @cindex target descriptions, predefined types | |
32165 | ||
32166 | Type definitions in the self-description can build up composite types | |
32167 | from basic building blocks, but can not define fundamental types. Instead, | |
32168 | standard identifiers are provided by @value{GDBN} for the fundamental | |
32169 | types. The currently supported types are: | |
32170 | ||
32171 | @table @code | |
32172 | ||
32173 | @item int8 | |
32174 | @itemx int16 | |
32175 | @itemx int32 | |
32176 | @itemx int64 | |
7cc46491 | 32177 | @itemx int128 |
123dc839 DJ |
32178 | Signed integer types holding the specified number of bits. |
32179 | ||
32180 | @item uint8 | |
32181 | @itemx uint16 | |
32182 | @itemx uint32 | |
32183 | @itemx uint64 | |
7cc46491 | 32184 | @itemx uint128 |
123dc839 DJ |
32185 | Unsigned integer types holding the specified number of bits. |
32186 | ||
32187 | @item code_ptr | |
32188 | @itemx data_ptr | |
32189 | Pointers to unspecified code and data. The program counter and | |
32190 | any dedicated return address register may be marked as code | |
32191 | pointers; printing a code pointer converts it into a symbolic | |
32192 | address. The stack pointer and any dedicated address registers | |
32193 | may be marked as data pointers. | |
32194 | ||
6e3bbd1a PB |
32195 | @item ieee_single |
32196 | Single precision IEEE floating point. | |
32197 | ||
32198 | @item ieee_double | |
32199 | Double precision IEEE floating point. | |
32200 | ||
123dc839 DJ |
32201 | @item arm_fpa_ext |
32202 | The 12-byte extended precision format used by ARM FPA registers. | |
32203 | ||
32204 | @end table | |
32205 | ||
32206 | @node Standard Target Features | |
32207 | @section Standard Target Features | |
32208 | @cindex target descriptions, standard features | |
32209 | ||
32210 | A target description must contain either no registers or all the | |
32211 | target's registers. If the description contains no registers, then | |
32212 | @value{GDBN} will assume a default register layout, selected based on | |
32213 | the architecture. If the description contains any registers, the | |
32214 | default layout will not be used; the standard registers must be | |
32215 | described in the target description, in such a way that @value{GDBN} | |
32216 | can recognize them. | |
32217 | ||
32218 | This is accomplished by giving specific names to feature elements | |
32219 | which contain standard registers. @value{GDBN} will look for features | |
32220 | with those names and verify that they contain the expected registers; | |
32221 | if any known feature is missing required registers, or if any required | |
32222 | feature is missing, @value{GDBN} will reject the target | |
32223 | description. You can add additional registers to any of the | |
32224 | standard features --- @value{GDBN} will display them just as if | |
32225 | they were added to an unrecognized feature. | |
32226 | ||
32227 | This section lists the known features and their expected contents. | |
32228 | Sample XML documents for these features are included in the | |
32229 | @value{GDBN} source tree, in the directory @file{gdb/features}. | |
32230 | ||
32231 | Names recognized by @value{GDBN} should include the name of the | |
32232 | company or organization which selected the name, and the overall | |
32233 | architecture to which the feature applies; so e.g.@: the feature | |
32234 | containing ARM core registers is named @samp{org.gnu.gdb.arm.core}. | |
32235 | ||
ff6f572f DJ |
32236 | The names of registers are not case sensitive for the purpose |
32237 | of recognizing standard features, but @value{GDBN} will only display | |
32238 | registers using the capitalization used in the description. | |
32239 | ||
e9c17194 VP |
32240 | @menu |
32241 | * ARM Features:: | |
1e26b4f8 | 32242 | * MIPS Features:: |
e9c17194 | 32243 | * M68K Features:: |
1e26b4f8 | 32244 | * PowerPC Features:: |
e9c17194 VP |
32245 | @end menu |
32246 | ||
32247 | ||
32248 | @node ARM Features | |
123dc839 DJ |
32249 | @subsection ARM Features |
32250 | @cindex target descriptions, ARM features | |
32251 | ||
32252 | The @samp{org.gnu.gdb.arm.core} feature is required for ARM targets. | |
32253 | It should contain registers @samp{r0} through @samp{r13}, @samp{sp}, | |
32254 | @samp{lr}, @samp{pc}, and @samp{cpsr}. | |
32255 | ||
32256 | The @samp{org.gnu.gdb.arm.fpa} feature is optional. If present, it | |
32257 | should contain registers @samp{f0} through @samp{f7} and @samp{fps}. | |
32258 | ||
ff6f572f DJ |
32259 | The @samp{org.gnu.gdb.xscale.iwmmxt} feature is optional. If present, |
32260 | it should contain at least registers @samp{wR0} through @samp{wR15} and | |
32261 | @samp{wCGR0} through @samp{wCGR3}. The @samp{wCID}, @samp{wCon}, | |
32262 | @samp{wCSSF}, and @samp{wCASF} registers are optional. | |
23181151 | 32263 | |
58d6951d DJ |
32264 | The @samp{org.gnu.gdb.arm.vfp} feature is optional. If present, it |
32265 | should contain at least registers @samp{d0} through @samp{d15}. If | |
32266 | they are present, @samp{d16} through @samp{d31} should also be included. | |
32267 | @value{GDBN} will synthesize the single-precision registers from | |
32268 | halves of the double-precision registers. | |
32269 | ||
32270 | The @samp{org.gnu.gdb.arm.neon} feature is optional. It does not | |
32271 | need to contain registers; it instructs @value{GDBN} to display the | |
32272 | VFP double-precision registers as vectors and to synthesize the | |
32273 | quad-precision registers from pairs of double-precision registers. | |
32274 | If this feature is present, @samp{org.gnu.gdb.arm.vfp} must also | |
32275 | be present and include 32 double-precision registers. | |
32276 | ||
1e26b4f8 | 32277 | @node MIPS Features |
f8b73d13 DJ |
32278 | @subsection MIPS Features |
32279 | @cindex target descriptions, MIPS features | |
32280 | ||
32281 | The @samp{org.gnu.gdb.mips.cpu} feature is required for MIPS targets. | |
32282 | It should contain registers @samp{r0} through @samp{r31}, @samp{lo}, | |
32283 | @samp{hi}, and @samp{pc}. They may be 32-bit or 64-bit depending | |
32284 | on the target. | |
32285 | ||
32286 | The @samp{org.gnu.gdb.mips.cp0} feature is also required. It should | |
32287 | contain at least the @samp{status}, @samp{badvaddr}, and @samp{cause} | |
32288 | registers. They may be 32-bit or 64-bit depending on the target. | |
32289 | ||
32290 | The @samp{org.gnu.gdb.mips.fpu} feature is currently required, though | |
32291 | it may be optional in a future version of @value{GDBN}. It should | |
32292 | contain registers @samp{f0} through @samp{f31}, @samp{fcsr}, and | |
32293 | @samp{fir}. They may be 32-bit or 64-bit depending on the target. | |
32294 | ||
822b6570 DJ |
32295 | The @samp{org.gnu.gdb.mips.linux} feature is optional. It should |
32296 | contain a single register, @samp{restart}, which is used by the | |
32297 | Linux kernel to control restartable syscalls. | |
32298 | ||
e9c17194 VP |
32299 | @node M68K Features |
32300 | @subsection M68K Features | |
32301 | @cindex target descriptions, M68K features | |
32302 | ||
32303 | @table @code | |
32304 | @item @samp{org.gnu.gdb.m68k.core} | |
32305 | @itemx @samp{org.gnu.gdb.coldfire.core} | |
32306 | @itemx @samp{org.gnu.gdb.fido.core} | |
32307 | One of those features must be always present. | |
249e1128 | 32308 | The feature that is present determines which flavor of m68k is |
e9c17194 VP |
32309 | used. The feature that is present should contain registers |
32310 | @samp{d0} through @samp{d7}, @samp{a0} through @samp{a5}, @samp{fp}, | |
32311 | @samp{sp}, @samp{ps} and @samp{pc}. | |
32312 | ||
32313 | @item @samp{org.gnu.gdb.coldfire.fp} | |
32314 | This feature is optional. If present, it should contain registers | |
32315 | @samp{fp0} through @samp{fp7}, @samp{fpcontrol}, @samp{fpstatus} and | |
32316 | @samp{fpiaddr}. | |
32317 | @end table | |
32318 | ||
1e26b4f8 | 32319 | @node PowerPC Features |
7cc46491 DJ |
32320 | @subsection PowerPC Features |
32321 | @cindex target descriptions, PowerPC features | |
32322 | ||
32323 | The @samp{org.gnu.gdb.power.core} feature is required for PowerPC | |
32324 | targets. It should contain registers @samp{r0} through @samp{r31}, | |
32325 | @samp{pc}, @samp{msr}, @samp{cr}, @samp{lr}, @samp{ctr}, and | |
32326 | @samp{xer}. They may be 32-bit or 64-bit depending on the target. | |
32327 | ||
32328 | The @samp{org.gnu.gdb.power.fpu} feature is optional. It should | |
32329 | contain registers @samp{f0} through @samp{f31} and @samp{fpscr}. | |
32330 | ||
32331 | The @samp{org.gnu.gdb.power.altivec} feature is optional. It should | |
32332 | contain registers @samp{vr0} through @samp{vr31}, @samp{vscr}, | |
32333 | and @samp{vrsave}. | |
32334 | ||
677c5bb1 LM |
32335 | The @samp{org.gnu.gdb.power.vsx} feature is optional. It should |
32336 | contain registers @samp{vs0h} through @samp{vs31h}. @value{GDBN} | |
32337 | will combine these registers with the floating point registers | |
32338 | (@samp{f0} through @samp{f31}) and the altivec registers (@samp{vr0} | |
aeac0ff9 | 32339 | through @samp{vr31}) to present the 128-bit wide registers @samp{vs0} |
677c5bb1 LM |
32340 | through @samp{vs63}, the set of vector registers for POWER7. |
32341 | ||
7cc46491 DJ |
32342 | The @samp{org.gnu.gdb.power.spe} feature is optional. It should |
32343 | contain registers @samp{ev0h} through @samp{ev31h}, @samp{acc}, and | |
32344 | @samp{spefscr}. SPE targets should provide 32-bit registers in | |
32345 | @samp{org.gnu.gdb.power.core} and provide the upper halves in | |
32346 | @samp{ev0h} through @samp{ev31h}. @value{GDBN} will combine | |
32347 | these to present registers @samp{ev0} through @samp{ev31} to the | |
32348 | user. | |
32349 | ||
07e059b5 VP |
32350 | @node Operating System Information |
32351 | @appendix Operating System Information | |
32352 | @cindex operating system information | |
32353 | ||
32354 | @menu | |
32355 | * Process list:: | |
32356 | @end menu | |
32357 | ||
32358 | Users of @value{GDBN} often wish to obtain information about the state of | |
32359 | the operating system running on the target---for example the list of | |
32360 | processes, or the list of open files. This section describes the | |
32361 | mechanism that makes it possible. This mechanism is similar to the | |
32362 | target features mechanism (@pxref{Target Descriptions}), but focuses | |
32363 | on a different aspect of target. | |
32364 | ||
32365 | Operating system information is retrived from the target via the | |
32366 | remote protocol, using @samp{qXfer} requests (@pxref{qXfer osdata | |
32367 | read}). The object name in the request should be @samp{osdata}, and | |
32368 | the @var{annex} identifies the data to be fetched. | |
32369 | ||
32370 | @node Process list | |
32371 | @appendixsection Process list | |
32372 | @cindex operating system information, process list | |
32373 | ||
32374 | When requesting the process list, the @var{annex} field in the | |
32375 | @samp{qXfer} request should be @samp{processes}. The returned data is | |
32376 | an XML document. The formal syntax of this document is defined in | |
32377 | @file{gdb/features/osdata.dtd}. | |
32378 | ||
32379 | An example document is: | |
32380 | ||
32381 | @smallexample | |
32382 | <?xml version="1.0"?> | |
32383 | <!DOCTYPE target SYSTEM "osdata.dtd"> | |
32384 | <osdata type="processes"> | |
32385 | <item> | |
32386 | <column name="pid">1</column> | |
32387 | <column name="user">root</column> | |
32388 | <column name="command">/sbin/init</column> | |
32389 | </item> | |
32390 | </osdata> | |
32391 | @end smallexample | |
32392 | ||
32393 | Each item should include a column whose name is @samp{pid}. The value | |
32394 | of that column should identify the process on the target. The | |
32395 | @samp{user} and @samp{command} columns are optional, and will be | |
32396 | displayed by @value{GDBN}. Target may provide additional columns, | |
32397 | which @value{GDBN} currently ignores. | |
32398 | ||
aab4e0ec | 32399 | @include gpl.texi |
eb12ee30 | 32400 | |
2154891a | 32401 | @raisesections |
6826cf00 | 32402 | @include fdl.texi |
2154891a | 32403 | @lowersections |
6826cf00 | 32404 | |
6d2ebf8b | 32405 | @node Index |
c906108c SS |
32406 | @unnumbered Index |
32407 | ||
32408 | @printindex cp | |
32409 | ||
32410 | @tex | |
32411 | % I think something like @colophon should be in texinfo. In the | |
32412 | % meantime: | |
32413 | \long\def\colophon{\hbox to0pt{}\vfill | |
32414 | \centerline{The body of this manual is set in} | |
32415 | \centerline{\fontname\tenrm,} | |
32416 | \centerline{with headings in {\bf\fontname\tenbf}} | |
32417 | \centerline{and examples in {\tt\fontname\tentt}.} | |
32418 | \centerline{{\it\fontname\tenit\/},} | |
32419 | \centerline{{\bf\fontname\tenbf}, and} | |
32420 | \centerline{{\sl\fontname\tensl\/}} | |
32421 | \centerline{are used for emphasis.}\vfill} | |
32422 | \page\colophon | |
32423 | % Blame: doc@cygnus.com, 1991. | |
32424 | @end tex | |
32425 | ||
c906108c | 32426 | @bye |