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c906108c | 1 | \input texinfo @c -*-texinfo-*- |
b6ba6518 KB |
2 | @c Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, |
3 | @c 1999, 2000, 2001 | |
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 | |
24 | ||
41afff9a | 25 | @c readline appendices use @vindex, @findex and @ftable, |
48e934c6 | 26 | @c annotate.texi and gdbmi use @findex. |
c906108c | 27 | @syncodeindex vr cp |
41afff9a | 28 | @syncodeindex fn cp |
c906108c SS |
29 | |
30 | @c !!set GDB manual's edition---not the same as GDB version! | |
e9c75b65 | 31 | @set EDITION Ninth |
c906108c SS |
32 | |
33 | @c !!set GDB manual's revision date | |
959acfd1 | 34 | @set DATE December 2001 |
c906108c | 35 | |
6d2ebf8b | 36 | @c THIS MANUAL REQUIRES TEXINFO 3.12 OR LATER. |
c906108c | 37 | |
c906108c | 38 | @c This is a dir.info fragment to support semi-automated addition of |
6d2ebf8b | 39 | @c manuals to an info tree. |
96a2c332 SS |
40 | @dircategory Programming & development tools. |
41 | @direntry | |
c906108c | 42 | * Gdb: (gdb). The @sc{gnu} debugger. |
96a2c332 SS |
43 | @end direntry |
44 | ||
c906108c SS |
45 | @ifinfo |
46 | This file documents the @sc{gnu} debugger @value{GDBN}. | |
47 | ||
48 | ||
5d161b24 | 49 | This is the @value{EDITION} Edition, @value{DATE}, |
c906108c SS |
50 | of @cite{Debugging with @value{GDBN}: the @sc{gnu} Source-Level Debugger} |
51 | for @value{GDBN} Version @value{GDBVN}. | |
52 | ||
6826cf00 | 53 | Copyright (C) 1988,1989,1990,1991,1992,1993,1994,1995,1996,1998,1999,2000,2001, 2002 Free Software Foundation, Inc. |
c906108c | 54 | |
e9c75b65 EZ |
55 | Permission is granted to copy, distribute and/or modify this document |
56 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
57 | any later version published by the Free Software Foundation; with the | |
959acfd1 EZ |
58 | Invariant Sections being ``Free Software'' and ``Free Software Needs |
59 | Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' | |
60 | and with the Back-Cover Texts as in (a) below. | |
c906108c | 61 | |
6826cf00 EZ |
62 | (a) The Free Software Foundation's Back-Cover Text is: ``You have |
63 | freedom to copy and modify this GNU Manual, like GNU software. Copies | |
64 | published by the Free Software Foundation raise funds for GNU | |
65 | development.'' | |
c906108c SS |
66 | @end ifinfo |
67 | ||
68 | @titlepage | |
69 | @title Debugging with @value{GDBN} | |
70 | @subtitle The @sc{gnu} Source-Level Debugger | |
c906108c | 71 | @sp 1 |
c906108c SS |
72 | @subtitle @value{EDITION} Edition, for @value{GDBN} version @value{GDBVN} |
73 | @subtitle @value{DATE} | |
9e9c5ae7 | 74 | @author Richard Stallman, Roland Pesch, Stan Shebs, et al. |
c906108c | 75 | @page |
c906108c SS |
76 | @tex |
77 | {\parskip=0pt | |
53a5351d | 78 | \hfill (Send bugs and comments on @value{GDBN} to bug-gdb\@gnu.org.)\par |
c906108c SS |
79 | \hfill {\it Debugging with @value{GDBN}}\par |
80 | \hfill \TeX{}info \texinfoversion\par | |
81 | } | |
82 | @end tex | |
53a5351d | 83 | |
c906108c | 84 | @vskip 0pt plus 1filll |
6826cf00 EZ |
85 | Copyright @copyright{} 1988,1989,1990,1991,1992,1993,1994,1995,1996,@* |
86 | 1998,1999,2000,2001,2002 Free Software Foundation, Inc. | |
c906108c | 87 | @sp 2 |
c906108c SS |
88 | Published by the Free Software Foundation @* |
89 | 59 Temple Place - Suite 330, @* | |
90 | Boston, MA 02111-1307 USA @* | |
6d2ebf8b | 91 | ISBN 1-882114-77-9 @* |
e9c75b65 EZ |
92 | |
93 | Permission is granted to copy, distribute and/or modify this document | |
94 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
95 | any later version published by the Free Software Foundation; with the | |
959acfd1 EZ |
96 | Invariant Sections being ``Free Software'' and ``Free Software Needs |
97 | Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' | |
98 | and with the Back-Cover Texts as in (a) below. | |
e9c75b65 | 99 | |
6826cf00 EZ |
100 | (a) The Free Software Foundation's Back-Cover Text is: ``You have |
101 | freedom to copy and modify this GNU Manual, like GNU software. Copies | |
102 | published by the Free Software Foundation raise funds for GNU | |
103 | development.'' | |
c906108c SS |
104 | @end titlepage |
105 | @page | |
106 | ||
b9deaee7 | 107 | @ifinfo |
6d2ebf8b SS |
108 | @node Top, Summary, (dir), (dir) |
109 | ||
c906108c SS |
110 | @top Debugging with @value{GDBN} |
111 | ||
112 | This file describes @value{GDBN}, the @sc{gnu} symbolic debugger. | |
113 | ||
5d161b24 | 114 | This is the @value{EDITION} Edition, @value{DATE}, for @value{GDBN} Version |
c906108c SS |
115 | @value{GDBVN}. |
116 | ||
e9c75b65 | 117 | Copyright (C) 1988-2001 Free Software Foundation, Inc. |
6d2ebf8b SS |
118 | |
119 | @menu | |
120 | * Summary:: Summary of @value{GDBN} | |
121 | * Sample Session:: A sample @value{GDBN} session | |
122 | ||
123 | * Invocation:: Getting in and out of @value{GDBN} | |
124 | * Commands:: @value{GDBN} commands | |
125 | * Running:: Running programs under @value{GDBN} | |
126 | * Stopping:: Stopping and continuing | |
127 | * Stack:: Examining the stack | |
128 | * Source:: Examining source files | |
129 | * Data:: Examining data | |
b37052ae | 130 | * Tracepoints:: Debugging remote targets non-intrusively |
df0cd8c5 | 131 | * Overlays:: Debugging programs that use overlays |
6d2ebf8b SS |
132 | |
133 | * Languages:: Using @value{GDBN} with different languages | |
134 | ||
135 | * Symbols:: Examining the symbol table | |
136 | * Altering:: Altering execution | |
137 | * GDB Files:: @value{GDBN} files | |
138 | * Targets:: Specifying a debugging target | |
139 | * Configurations:: Configuration-specific information | |
140 | * Controlling GDB:: Controlling @value{GDBN} | |
141 | * Sequences:: Canned sequences of commands | |
c4555f82 | 142 | * TUI:: @value{GDBN} Text User Interface |
6d2ebf8b SS |
143 | * Emacs:: Using @value{GDBN} under @sc{gnu} Emacs |
144 | * Annotations:: @value{GDBN}'s annotation interface. | |
7162c0ca | 145 | * GDB/MI:: @value{GDBN}'s Machine Interface. |
6d2ebf8b SS |
146 | |
147 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
148 | * Formatting Documentation:: How to format and print @value{GDBN} documentation | |
149 | ||
150 | * Command Line Editing:: Command Line Editing | |
151 | * Using History Interactively:: Using History Interactively | |
152 | * Installing GDB:: Installing GDB | |
eb12ee30 | 153 | * Maintenance Commands:: Maintenance Commands |
6826cf00 | 154 | * GNU Free Documentation License:: The license for this documentation |
6d2ebf8b SS |
155 | * Index:: Index |
156 | @end menu | |
157 | ||
b9deaee7 | 158 | @end ifinfo |
6d2ebf8b SS |
159 | |
160 | @c the replication sucks, but this avoids a texinfo 3.12 lameness | |
161 | ||
162 | @ifhtml | |
163 | @node Top | |
164 | ||
165 | @top Debugging with @value{GDBN} | |
166 | ||
167 | This file describes @value{GDBN}, the @sc{gnu} symbolic debugger. | |
168 | ||
b37052ae | 169 | This is the @value{EDITION} Edition, @value{DATE}, for @value{GDBN} Version |
6d2ebf8b SS |
170 | @value{GDBVN}. |
171 | ||
172 | Copyright (C) 1988-2000 Free Software Foundation, Inc. | |
173 | ||
c906108c SS |
174 | @menu |
175 | * Summary:: Summary of @value{GDBN} | |
c906108c | 176 | * Sample Session:: A sample @value{GDBN} session |
c906108c SS |
177 | |
178 | * Invocation:: Getting in and out of @value{GDBN} | |
179 | * Commands:: @value{GDBN} commands | |
180 | * Running:: Running programs under @value{GDBN} | |
181 | * Stopping:: Stopping and continuing | |
182 | * Stack:: Examining the stack | |
183 | * Source:: Examining source files | |
184 | * Data:: Examining data | |
496e6bc3 | 185 | * Tracepoints:: Debugging remote targets non-intrusively |
df0cd8c5 | 186 | * Overlays:: Debugging programs that use overlays |
c906108c | 187 | |
7a292a7a | 188 | * Languages:: Using @value{GDBN} with different languages |
c906108c SS |
189 | |
190 | * Symbols:: Examining the symbol table | |
191 | * Altering:: Altering execution | |
192 | * GDB Files:: @value{GDBN} files | |
193 | * Targets:: Specifying a debugging target | |
104c1213 | 194 | * Configurations:: Configuration-specific information |
c906108c SS |
195 | * Controlling GDB:: Controlling @value{GDBN} |
196 | * Sequences:: Canned sequences of commands | |
496e6bc3 | 197 | * TUI:: @value{GDBN} Text User Interface |
c906108c | 198 | * Emacs:: Using @value{GDBN} under @sc{gnu} Emacs |
6d2ebf8b | 199 | * Annotations:: @value{GDBN}'s annotation interface. |
496e6bc3 | 200 | * GDB/MI:: @value{GDBN}'s Machine Interface. |
c906108c SS |
201 | |
202 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
c906108c | 203 | * Formatting Documentation:: How to format and print @value{GDBN} documentation |
c906108c SS |
204 | |
205 | * Command Line Editing:: Command Line Editing | |
206 | * Using History Interactively:: Using History Interactively | |
207 | * Installing GDB:: Installing GDB | |
eb12ee30 | 208 | * Maintenance Commands:: Maintenance Commands |
6826cf00 | 209 | * GNU Free Documentation License:: The license for this documentation |
c906108c | 210 | * Index:: Index |
c906108c SS |
211 | @end menu |
212 | ||
6d2ebf8b SS |
213 | @end ifhtml |
214 | ||
449f3b6c AC |
215 | @c TeX can handle the contents at the start but makeinfo 3.12 can not |
216 | @iftex | |
217 | @contents | |
218 | @end iftex | |
219 | ||
6d2ebf8b | 220 | @node Summary |
c906108c SS |
221 | @unnumbered Summary of @value{GDBN} |
222 | ||
223 | The purpose of a debugger such as @value{GDBN} is to allow you to see what is | |
224 | going on ``inside'' another program while it executes---or what another | |
225 | program was doing at the moment it crashed. | |
226 | ||
227 | @value{GDBN} can do four main kinds of things (plus other things in support of | |
228 | these) to help you catch bugs in the act: | |
229 | ||
230 | @itemize @bullet | |
231 | @item | |
232 | Start your program, specifying anything that might affect its behavior. | |
233 | ||
234 | @item | |
235 | Make your program stop on specified conditions. | |
236 | ||
237 | @item | |
238 | Examine what has happened, when your program has stopped. | |
239 | ||
240 | @item | |
241 | Change things in your program, so you can experiment with correcting the | |
242 | effects of one bug and go on to learn about another. | |
243 | @end itemize | |
244 | ||
cce74817 | 245 | You can use @value{GDBN} to debug programs written in C and C++. |
c906108c | 246 | For more information, see @ref{Support,,Supported languages}. |
c906108c SS |
247 | For more information, see @ref{C,,C and C++}. |
248 | ||
cce74817 JM |
249 | @cindex Chill |
250 | @cindex Modula-2 | |
c906108c | 251 | Support for Modula-2 and Chill is partial. For information on Modula-2, |
cce74817 | 252 | see @ref{Modula-2,,Modula-2}. For information on Chill, see @ref{Chill}. |
c906108c | 253 | |
cce74817 JM |
254 | @cindex Pascal |
255 | Debugging Pascal programs which use sets, subranges, file variables, or | |
256 | nested functions does not currently work. @value{GDBN} does not support | |
257 | entering expressions, printing values, or similar features using Pascal | |
258 | syntax. | |
c906108c | 259 | |
c906108c SS |
260 | @cindex Fortran |
261 | @value{GDBN} can be used to debug programs written in Fortran, although | |
53a5351d | 262 | it may be necessary to refer to some variables with a trailing |
cce74817 | 263 | underscore. |
c906108c | 264 | |
c906108c SS |
265 | @menu |
266 | * Free Software:: Freely redistributable software | |
267 | * Contributors:: Contributors to GDB | |
268 | @end menu | |
269 | ||
6d2ebf8b | 270 | @node Free Software |
c906108c SS |
271 | @unnumberedsec Free software |
272 | ||
5d161b24 | 273 | @value{GDBN} is @dfn{free software}, protected by the @sc{gnu} |
c906108c SS |
274 | General Public License |
275 | (GPL). The GPL gives you the freedom to copy or adapt a licensed | |
276 | program---but every person getting a copy also gets with it the | |
277 | freedom to modify that copy (which means that they must get access to | |
278 | the source code), and the freedom to distribute further copies. | |
279 | Typical software companies use copyrights to limit your freedoms; the | |
280 | Free Software Foundation uses the GPL to preserve these freedoms. | |
281 | ||
282 | Fundamentally, the General Public License is a license which says that | |
283 | you have these freedoms and that you cannot take these freedoms away | |
284 | from anyone else. | |
285 | ||
2666264b | 286 | @unnumberedsec Free Software Needs Free Documentation |
959acfd1 EZ |
287 | |
288 | The biggest deficiency in the free software community today is not in | |
289 | the software---it is the lack of good free documentation that we can | |
290 | include with the free software. Many of our most important | |
291 | programs do not come with free reference manuals and free introductory | |
292 | texts. Documentation is an essential part of any software package; | |
293 | when an important free software package does not come with a free | |
294 | manual and a free tutorial, that is a major gap. We have many such | |
295 | gaps today. | |
296 | ||
297 | Consider Perl, for instance. The tutorial manuals that people | |
298 | normally use are non-free. How did this come about? Because the | |
299 | authors of those manuals published them with restrictive terms---no | |
300 | copying, no modification, source files not available---which exclude | |
301 | them from the free software world. | |
302 | ||
303 | That wasn't the first time this sort of thing happened, and it was far | |
304 | from the last. Many times we have heard a GNU user eagerly describe a | |
305 | manual that he is writing, his intended contribution to the community, | |
306 | only to learn that he had ruined everything by signing a publication | |
307 | contract to make it non-free. | |
308 | ||
309 | Free documentation, like free software, is a matter of freedom, not | |
310 | price. The problem with the non-free manual is not that publishers | |
311 | charge a price for printed copies---that in itself is fine. (The Free | |
312 | Software Foundation sells printed copies of manuals, too.) The | |
313 | problem is the restrictions on the use of the manual. Free manuals | |
314 | are available in source code form, and give you permission to copy and | |
315 | modify. Non-free manuals do not allow this. | |
316 | ||
317 | The criteria of freedom for a free manual are roughly the same as for | |
318 | free software. Redistribution (including the normal kinds of | |
319 | commercial redistribution) must be permitted, so that the manual can | |
320 | accompany every copy of the program, both on-line and on paper. | |
321 | ||
322 | Permission for modification of the technical content is crucial too. | |
323 | When people modify the software, adding or changing features, if they | |
324 | are conscientious they will change the manual too---so they can | |
325 | provide accurate and clear documentation for the modified program. A | |
326 | manual that leaves you no choice but to write a new manual to document | |
327 | a changed version of the program is not really available to our | |
328 | community. | |
329 | ||
330 | Some kinds of limits on the way modification is handled are | |
331 | acceptable. For example, requirements to preserve the original | |
332 | author's copyright notice, the distribution terms, or the list of | |
333 | authors, are ok. It is also no problem to require modified versions | |
334 | to include notice that they were modified. Even entire sections that | |
335 | may not be deleted or changed are acceptable, as long as they deal | |
336 | with nontechnical topics (like this one). These kinds of restrictions | |
337 | are acceptable because they don't obstruct the community's normal use | |
338 | of the manual. | |
339 | ||
340 | However, it must be possible to modify all the @emph{technical} | |
341 | content of the manual, and then distribute the result in all the usual | |
342 | media, through all the usual channels. Otherwise, the restrictions | |
343 | obstruct the use of the manual, it is not free, and we need another | |
344 | manual to replace it. | |
345 | ||
346 | Please spread the word about this issue. Our community continues to | |
347 | lose manuals to proprietary publishing. If we spread the word that | |
348 | free software needs free reference manuals and free tutorials, perhaps | |
349 | the next person who wants to contribute by writing documentation will | |
350 | realize, before it is too late, that only free manuals contribute to | |
351 | the free software community. | |
352 | ||
353 | If you are writing documentation, please insist on publishing it under | |
354 | the GNU Free Documentation License or another free documentation | |
355 | license. Remember that this decision requires your approval---you | |
356 | don't have to let the publisher decide. Some commercial publishers | |
357 | will use a free license if you insist, but they will not propose the | |
358 | option; it is up to you to raise the issue and say firmly that this is | |
359 | what you want. If the publisher you are dealing with refuses, please | |
360 | try other publishers. If you're not sure whether a proposed license | |
42584a72 | 361 | is free, write to @email{licensing@@gnu.org}. |
959acfd1 EZ |
362 | |
363 | You can encourage commercial publishers to sell more free, copylefted | |
364 | manuals and tutorials by buying them, and particularly by buying | |
365 | copies from the publishers that paid for their writing or for major | |
366 | improvements. Meanwhile, try to avoid buying non-free documentation | |
367 | at all. Check the distribution terms of a manual before you buy it, | |
368 | and insist that whoever seeks your business must respect your freedom. | |
72c9928d EZ |
369 | Check the history of the book, and try to reward the publishers that |
370 | have paid or pay the authors to work on it. | |
959acfd1 EZ |
371 | |
372 | The Free Software Foundation maintains a list of free documentation | |
373 | published by other publishers, at | |
374 | @url{http://www.fsf.org/doc/other-free-books.html}. | |
375 | ||
6d2ebf8b | 376 | @node Contributors |
96a2c332 SS |
377 | @unnumberedsec Contributors to @value{GDBN} |
378 | ||
379 | Richard Stallman was the original author of @value{GDBN}, and of many | |
380 | other @sc{gnu} programs. Many others have contributed to its | |
381 | development. This section attempts to credit major contributors. One | |
382 | of the virtues of free software is that everyone is free to contribute | |
383 | to it; with regret, we cannot actually acknowledge everyone here. The | |
384 | file @file{ChangeLog} in the @value{GDBN} distribution approximates a | |
c906108c SS |
385 | blow-by-blow account. |
386 | ||
387 | Changes much prior to version 2.0 are lost in the mists of time. | |
388 | ||
389 | @quotation | |
390 | @emph{Plea:} Additions to this section are particularly welcome. If you | |
391 | or your friends (or enemies, to be evenhanded) have been unfairly | |
392 | omitted from this list, we would like to add your names! | |
393 | @end quotation | |
394 | ||
395 | So that they may not regard their many labors as thankless, we | |
396 | particularly thank those who shepherded @value{GDBN} through major | |
397 | releases: | |
b37052ae | 398 | Andrew Cagney (releases 5.0 and 5.1); |
c906108c SS |
399 | Jim Blandy (release 4.18); |
400 | Jason Molenda (release 4.17); | |
401 | Stan Shebs (release 4.14); | |
402 | Fred Fish (releases 4.16, 4.15, 4.13, 4.12, 4.11, 4.10, and 4.9); | |
403 | Stu Grossman and John Gilmore (releases 4.8, 4.7, 4.6, 4.5, and 4.4); | |
404 | John Gilmore (releases 4.3, 4.2, 4.1, 4.0, and 3.9); | |
405 | Jim Kingdon (releases 3.5, 3.4, and 3.3); | |
406 | and Randy Smith (releases 3.2, 3.1, and 3.0). | |
407 | ||
408 | Richard Stallman, assisted at various times by Peter TerMaat, Chris | |
409 | Hanson, and Richard Mlynarik, handled releases through 2.8. | |
410 | ||
b37052ae EZ |
411 | Michael Tiemann is the author of most of the @sc{gnu} C@t{++} support |
412 | in @value{GDBN}, with significant additional contributions from Per | |
413 | Bothner and Daniel Berlin. James Clark wrote the @sc{gnu} C@t{++} | |
414 | demangler. Early work on C@t{++} was by Peter TerMaat (who also did | |
415 | much general update work leading to release 3.0). | |
c906108c | 416 | |
b37052ae | 417 | @value{GDBN} uses the BFD subroutine library to examine multiple |
c906108c SS |
418 | object-file formats; BFD was a joint project of David V. |
419 | Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore. | |
420 | ||
421 | David Johnson wrote the original COFF support; Pace Willison did | |
422 | the original support for encapsulated COFF. | |
423 | ||
96c405b3 | 424 | Brent Benson of Harris Computer Systems contributed DWARF2 support. |
c906108c SS |
425 | |
426 | Adam de Boor and Bradley Davis contributed the ISI Optimum V support. | |
427 | Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS | |
428 | support. | |
429 | Jean-Daniel Fekete contributed Sun 386i support. | |
430 | Chris Hanson improved the HP9000 support. | |
431 | Noboyuki Hikichi and Tomoyuki Hasei contributed Sony/News OS 3 support. | |
432 | David Johnson contributed Encore Umax support. | |
433 | Jyrki Kuoppala contributed Altos 3068 support. | |
434 | Jeff Law contributed HP PA and SOM support. | |
435 | Keith Packard contributed NS32K support. | |
436 | Doug Rabson contributed Acorn Risc Machine support. | |
437 | Bob Rusk contributed Harris Nighthawk CX-UX support. | |
438 | Chris Smith contributed Convex support (and Fortran debugging). | |
439 | Jonathan Stone contributed Pyramid support. | |
440 | Michael Tiemann contributed SPARC support. | |
441 | Tim Tucker contributed support for the Gould NP1 and Gould Powernode. | |
442 | Pace Willison contributed Intel 386 support. | |
443 | Jay Vosburgh contributed Symmetry support. | |
444 | ||
445 | Andreas Schwab contributed M68K Linux support. | |
446 | ||
447 | Rich Schaefer and Peter Schauer helped with support of SunOS shared | |
448 | libraries. | |
449 | ||
450 | Jay Fenlason and Roland McGrath ensured that @value{GDBN} and GAS agree | |
451 | about several machine instruction sets. | |
452 | ||
453 | Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped develop | |
454 | remote debugging. Intel Corporation, Wind River Systems, AMD, and ARM | |
455 | contributed remote debugging modules for the i960, VxWorks, A29K UDI, | |
456 | and RDI targets, respectively. | |
457 | ||
458 | Brian Fox is the author of the readline libraries providing | |
459 | command-line editing and command history. | |
460 | ||
7a292a7a SS |
461 | Andrew Beers of SUNY Buffalo wrote the language-switching code, the |
462 | Modula-2 support, and contributed the Languages chapter of this manual. | |
c906108c | 463 | |
5d161b24 | 464 | Fred Fish wrote most of the support for Unix System Vr4. |
b37052ae | 465 | He also enhanced the command-completion support to cover C@t{++} overloaded |
c906108c | 466 | symbols. |
c906108c SS |
467 | |
468 | Hitachi America, Ltd. sponsored the support for H8/300, H8/500, and | |
469 | Super-H processors. | |
470 | ||
471 | NEC sponsored the support for the v850, Vr4xxx, and Vr5xxx processors. | |
472 | ||
473 | Mitsubishi sponsored the support for D10V, D30V, and M32R/D processors. | |
474 | ||
475 | Toshiba sponsored the support for the TX39 Mips processor. | |
476 | ||
477 | Matsushita sponsored the support for the MN10200 and MN10300 processors. | |
478 | ||
96a2c332 | 479 | Fujitsu sponsored the support for SPARClite and FR30 processors. |
c906108c SS |
480 | |
481 | Kung Hsu, Jeff Law, and Rick Sladkey added support for hardware | |
482 | watchpoints. | |
483 | ||
484 | Michael Snyder added support for tracepoints. | |
485 | ||
486 | Stu Grossman wrote gdbserver. | |
487 | ||
488 | Jim Kingdon, Peter Schauer, Ian Taylor, and Stu Grossman made | |
96a2c332 | 489 | nearly innumerable bug fixes and cleanups throughout @value{GDBN}. |
c906108c SS |
490 | |
491 | The following people at the Hewlett-Packard Company contributed | |
492 | support for the PA-RISC 2.0 architecture, HP-UX 10.20, 10.30, and 11.0 | |
b37052ae | 493 | (narrow mode), HP's implementation of kernel threads, HP's aC@t{++} |
c906108c SS |
494 | compiler, and the terminal user interface: Ben Krepp, Richard Title, |
495 | John Bishop, Susan Macchia, Kathy Mann, Satish Pai, India Paul, Steve | |
496 | Rehrauer, and Elena Zannoni. Kim Haase provided HP-specific | |
497 | information in this manual. | |
498 | ||
b37052ae EZ |
499 | DJ Delorie ported @value{GDBN} to MS-DOS, for the DJGPP project. |
500 | Robert Hoehne made significant contributions to the DJGPP port. | |
501 | ||
96a2c332 SS |
502 | Cygnus Solutions has sponsored @value{GDBN} maintenance and much of its |
503 | development since 1991. Cygnus engineers who have worked on @value{GDBN} | |
2df3850c JM |
504 | fulltime include Mark Alexander, Jim Blandy, Per Bothner, Kevin |
505 | Buettner, Edith Epstein, Chris Faylor, Fred Fish, Martin Hunt, Jim | |
506 | Ingham, John Gilmore, Stu Grossman, Kung Hsu, Jim Kingdon, John Metzler, | |
507 | Fernando Nasser, Geoffrey Noer, Dawn Perchik, Rich Pixley, Zdenek | |
508 | Radouch, Keith Seitz, Stan Shebs, David Taylor, and Elena Zannoni. In | |
509 | addition, Dave Brolley, Ian Carmichael, Steve Chamberlain, Nick Clifton, | |
510 | JT Conklin, Stan Cox, DJ Delorie, Ulrich Drepper, Frank Eigler, Doug | |
511 | Evans, Sean Fagan, David Henkel-Wallace, Richard Henderson, Jeff | |
512 | Holcomb, Jeff Law, Jim Lemke, Tom Lord, Bob Manson, Michael Meissner, | |
513 | Jason Merrill, Catherine Moore, Drew Moseley, Ken Raeburn, Gavin | |
514 | Romig-Koch, Rob Savoye, Jamie Smith, Mike Stump, Ian Taylor, Angela | |
515 | Thomas, Michael Tiemann, Tom Tromey, Ron Unrau, Jim Wilson, and David | |
516 | Zuhn have made contributions both large and small. | |
c906108c SS |
517 | |
518 | ||
6d2ebf8b | 519 | @node Sample Session |
c906108c SS |
520 | @chapter A Sample @value{GDBN} Session |
521 | ||
522 | You can use this manual at your leisure to read all about @value{GDBN}. | |
523 | However, a handful of commands are enough to get started using the | |
524 | debugger. This chapter illustrates those commands. | |
525 | ||
526 | @iftex | |
527 | In this sample session, we emphasize user input like this: @b{input}, | |
528 | to make it easier to pick out from the surrounding output. | |
529 | @end iftex | |
530 | ||
531 | @c FIXME: this example may not be appropriate for some configs, where | |
532 | @c FIXME...primary interest is in remote use. | |
533 | ||
534 | One of the preliminary versions of @sc{gnu} @code{m4} (a generic macro | |
535 | processor) exhibits the following bug: sometimes, when we change its | |
536 | quote strings from the default, the commands used to capture one macro | |
537 | definition within another stop working. In the following short @code{m4} | |
538 | session, we define a macro @code{foo} which expands to @code{0000}; we | |
539 | then use the @code{m4} built-in @code{defn} to define @code{bar} as the | |
540 | same thing. However, when we change the open quote string to | |
541 | @code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same | |
542 | procedure fails to define a new synonym @code{baz}: | |
543 | ||
544 | @smallexample | |
545 | $ @b{cd gnu/m4} | |
546 | $ @b{./m4} | |
547 | @b{define(foo,0000)} | |
548 | ||
549 | @b{foo} | |
550 | 0000 | |
551 | @b{define(bar,defn(`foo'))} | |
552 | ||
553 | @b{bar} | |
554 | 0000 | |
555 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
556 | ||
557 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
558 | @b{baz} | |
559 | @b{C-d} | |
560 | m4: End of input: 0: fatal error: EOF in string | |
561 | @end smallexample | |
562 | ||
563 | @noindent | |
564 | Let us use @value{GDBN} to try to see what is going on. | |
565 | ||
c906108c SS |
566 | @smallexample |
567 | $ @b{@value{GDBP} m4} | |
568 | @c FIXME: this falsifies the exact text played out, to permit smallbook | |
569 | @c FIXME... format to come out better. | |
570 | @value{GDBN} is free software and you are welcome to distribute copies | |
5d161b24 | 571 | of it under certain conditions; type "show copying" to see |
c906108c | 572 | the conditions. |
5d161b24 | 573 | There is absolutely no warranty for @value{GDBN}; type "show warranty" |
c906108c SS |
574 | for details. |
575 | ||
576 | @value{GDBN} @value{GDBVN}, Copyright 1999 Free Software Foundation, Inc... | |
577 | (@value{GDBP}) | |
578 | @end smallexample | |
c906108c SS |
579 | |
580 | @noindent | |
581 | @value{GDBN} reads only enough symbol data to know where to find the | |
582 | rest when needed; as a result, the first prompt comes up very quickly. | |
583 | We now tell @value{GDBN} to use a narrower display width than usual, so | |
584 | that examples fit in this manual. | |
585 | ||
586 | @smallexample | |
587 | (@value{GDBP}) @b{set width 70} | |
588 | @end smallexample | |
589 | ||
590 | @noindent | |
591 | We need to see how the @code{m4} built-in @code{changequote} works. | |
592 | Having looked at the source, we know the relevant subroutine is | |
593 | @code{m4_changequote}, so we set a breakpoint there with the @value{GDBN} | |
594 | @code{break} command. | |
595 | ||
596 | @smallexample | |
597 | (@value{GDBP}) @b{break m4_changequote} | |
598 | Breakpoint 1 at 0x62f4: file builtin.c, line 879. | |
599 | @end smallexample | |
600 | ||
601 | @noindent | |
602 | Using the @code{run} command, we start @code{m4} running under @value{GDBN} | |
603 | control; as long as control does not reach the @code{m4_changequote} | |
604 | subroutine, the program runs as usual: | |
605 | ||
606 | @smallexample | |
607 | (@value{GDBP}) @b{run} | |
608 | Starting program: /work/Editorial/gdb/gnu/m4/m4 | |
609 | @b{define(foo,0000)} | |
610 | ||
611 | @b{foo} | |
612 | 0000 | |
613 | @end smallexample | |
614 | ||
615 | @noindent | |
616 | To trigger the breakpoint, we call @code{changequote}. @value{GDBN} | |
617 | suspends execution of @code{m4}, displaying information about the | |
618 | context where it stops. | |
619 | ||
620 | @smallexample | |
621 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
622 | ||
5d161b24 | 623 | Breakpoint 1, m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
624 | at builtin.c:879 |
625 | 879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]),argc,1,3)) | |
626 | @end smallexample | |
627 | ||
628 | @noindent | |
629 | Now we use the command @code{n} (@code{next}) to advance execution to | |
630 | the next line of the current function. | |
631 | ||
632 | @smallexample | |
633 | (@value{GDBP}) @b{n} | |
634 | 882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\ | |
635 | : nil, | |
636 | @end smallexample | |
637 | ||
638 | @noindent | |
639 | @code{set_quotes} looks like a promising subroutine. We can go into it | |
640 | by using the command @code{s} (@code{step}) instead of @code{next}. | |
641 | @code{step} goes to the next line to be executed in @emph{any} | |
642 | subroutine, so it steps into @code{set_quotes}. | |
643 | ||
644 | @smallexample | |
645 | (@value{GDBP}) @b{s} | |
646 | set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
647 | at input.c:530 | |
648 | 530 if (lquote != def_lquote) | |
649 | @end smallexample | |
650 | ||
651 | @noindent | |
652 | The display that shows the subroutine where @code{m4} is now | |
653 | suspended (and its arguments) is called a stack frame display. It | |
654 | shows a summary of the stack. We can use the @code{backtrace} | |
655 | command (which can also be spelled @code{bt}), to see where we are | |
656 | in the stack as a whole: the @code{backtrace} command displays a | |
657 | stack frame for each active subroutine. | |
658 | ||
659 | @smallexample | |
660 | (@value{GDBP}) @b{bt} | |
661 | #0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
662 | at input.c:530 | |
5d161b24 | 663 | #1 0x6344 in m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
664 | at builtin.c:882 |
665 | #2 0x8174 in expand_macro (sym=0x33320) at macro.c:242 | |
666 | #3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30) | |
667 | at macro.c:71 | |
668 | #4 0x79dc in expand_input () at macro.c:40 | |
669 | #5 0x2930 in main (argc=0, argv=0xf7fffb20) at m4.c:195 | |
670 | @end smallexample | |
671 | ||
672 | @noindent | |
673 | We step through a few more lines to see what happens. The first two | |
674 | times, we can use @samp{s}; the next two times we use @code{n} to avoid | |
675 | falling into the @code{xstrdup} subroutine. | |
676 | ||
677 | @smallexample | |
678 | (@value{GDBP}) @b{s} | |
679 | 0x3b5c 532 if (rquote != def_rquote) | |
680 | (@value{GDBP}) @b{s} | |
681 | 0x3b80 535 lquote = (lq == nil || *lq == '\0') ? \ | |
682 | def_lquote : xstrdup(lq); | |
683 | (@value{GDBP}) @b{n} | |
684 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
685 | : xstrdup(rq); | |
686 | (@value{GDBP}) @b{n} | |
687 | 538 len_lquote = strlen(rquote); | |
688 | @end smallexample | |
689 | ||
690 | @noindent | |
691 | The last line displayed looks a little odd; we can examine the variables | |
692 | @code{lquote} and @code{rquote} to see if they are in fact the new left | |
693 | and right quotes we specified. We use the command @code{p} | |
694 | (@code{print}) to see their values. | |
695 | ||
696 | @smallexample | |
697 | (@value{GDBP}) @b{p lquote} | |
698 | $1 = 0x35d40 "<QUOTE>" | |
699 | (@value{GDBP}) @b{p rquote} | |
700 | $2 = 0x35d50 "<UNQUOTE>" | |
701 | @end smallexample | |
702 | ||
703 | @noindent | |
704 | @code{lquote} and @code{rquote} are indeed the new left and right quotes. | |
705 | To look at some context, we can display ten lines of source | |
706 | surrounding the current line with the @code{l} (@code{list}) command. | |
707 | ||
708 | @smallexample | |
709 | (@value{GDBP}) @b{l} | |
710 | 533 xfree(rquote); | |
711 | 534 | |
712 | 535 lquote = (lq == nil || *lq == '\0') ? def_lquote\ | |
713 | : xstrdup (lq); | |
714 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
715 | : xstrdup (rq); | |
716 | 537 | |
717 | 538 len_lquote = strlen(rquote); | |
718 | 539 len_rquote = strlen(lquote); | |
719 | 540 @} | |
720 | 541 | |
721 | 542 void | |
722 | @end smallexample | |
723 | ||
724 | @noindent | |
725 | Let us step past the two lines that set @code{len_lquote} and | |
726 | @code{len_rquote}, and then examine the values of those variables. | |
727 | ||
728 | @smallexample | |
729 | (@value{GDBP}) @b{n} | |
730 | 539 len_rquote = strlen(lquote); | |
731 | (@value{GDBP}) @b{n} | |
732 | 540 @} | |
733 | (@value{GDBP}) @b{p len_lquote} | |
734 | $3 = 9 | |
735 | (@value{GDBP}) @b{p len_rquote} | |
736 | $4 = 7 | |
737 | @end smallexample | |
738 | ||
739 | @noindent | |
740 | That certainly looks wrong, assuming @code{len_lquote} and | |
741 | @code{len_rquote} are meant to be the lengths of @code{lquote} and | |
742 | @code{rquote} respectively. We can set them to better values using | |
743 | the @code{p} command, since it can print the value of | |
744 | any expression---and that expression can include subroutine calls and | |
745 | assignments. | |
746 | ||
747 | @smallexample | |
748 | (@value{GDBP}) @b{p len_lquote=strlen(lquote)} | |
749 | $5 = 7 | |
750 | (@value{GDBP}) @b{p len_rquote=strlen(rquote)} | |
751 | $6 = 9 | |
752 | @end smallexample | |
753 | ||
754 | @noindent | |
755 | Is that enough to fix the problem of using the new quotes with the | |
756 | @code{m4} built-in @code{defn}? We can allow @code{m4} to continue | |
757 | executing with the @code{c} (@code{continue}) command, and then try the | |
758 | example that caused trouble initially: | |
759 | ||
760 | @smallexample | |
761 | (@value{GDBP}) @b{c} | |
762 | Continuing. | |
763 | ||
764 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
765 | ||
766 | baz | |
767 | 0000 | |
768 | @end smallexample | |
769 | ||
770 | @noindent | |
771 | Success! The new quotes now work just as well as the default ones. The | |
772 | problem seems to have been just the two typos defining the wrong | |
773 | lengths. We allow @code{m4} exit by giving it an EOF as input: | |
774 | ||
775 | @smallexample | |
776 | @b{C-d} | |
777 | Program exited normally. | |
778 | @end smallexample | |
779 | ||
780 | @noindent | |
781 | The message @samp{Program exited normally.} is from @value{GDBN}; it | |
782 | indicates @code{m4} has finished executing. We can end our @value{GDBN} | |
783 | session with the @value{GDBN} @code{quit} command. | |
784 | ||
785 | @smallexample | |
786 | (@value{GDBP}) @b{quit} | |
787 | @end smallexample | |
c906108c | 788 | |
6d2ebf8b | 789 | @node Invocation |
c906108c SS |
790 | @chapter Getting In and Out of @value{GDBN} |
791 | ||
792 | This chapter discusses how to start @value{GDBN}, and how to get out of it. | |
5d161b24 | 793 | The essentials are: |
c906108c | 794 | @itemize @bullet |
5d161b24 | 795 | @item |
53a5351d | 796 | type @samp{@value{GDBP}} to start @value{GDBN}. |
5d161b24 | 797 | @item |
c906108c SS |
798 | type @kbd{quit} or @kbd{C-d} to exit. |
799 | @end itemize | |
800 | ||
801 | @menu | |
802 | * Invoking GDB:: How to start @value{GDBN} | |
803 | * Quitting GDB:: How to quit @value{GDBN} | |
804 | * Shell Commands:: How to use shell commands inside @value{GDBN} | |
805 | @end menu | |
806 | ||
6d2ebf8b | 807 | @node Invoking GDB |
c906108c SS |
808 | @section Invoking @value{GDBN} |
809 | ||
c906108c SS |
810 | Invoke @value{GDBN} by running the program @code{@value{GDBP}}. Once started, |
811 | @value{GDBN} reads commands from the terminal until you tell it to exit. | |
812 | ||
813 | You can also run @code{@value{GDBP}} with a variety of arguments and options, | |
814 | to specify more of your debugging environment at the outset. | |
815 | ||
c906108c SS |
816 | The command-line options described here are designed |
817 | to cover a variety of situations; in some environments, some of these | |
5d161b24 | 818 | options may effectively be unavailable. |
c906108c SS |
819 | |
820 | The most usual way to start @value{GDBN} is with one argument, | |
821 | specifying an executable program: | |
822 | ||
823 | @example | |
824 | @value{GDBP} @var{program} | |
825 | @end example | |
826 | ||
c906108c SS |
827 | @noindent |
828 | You can also start with both an executable program and a core file | |
829 | specified: | |
830 | ||
831 | @example | |
832 | @value{GDBP} @var{program} @var{core} | |
833 | @end example | |
834 | ||
835 | You can, instead, specify a process ID as a second argument, if you want | |
836 | to debug a running process: | |
837 | ||
838 | @example | |
839 | @value{GDBP} @var{program} 1234 | |
840 | @end example | |
841 | ||
842 | @noindent | |
843 | would attach @value{GDBN} to process @code{1234} (unless you also have a file | |
844 | named @file{1234}; @value{GDBN} does check for a core file first). | |
845 | ||
c906108c | 846 | Taking advantage of the second command-line argument requires a fairly |
2df3850c JM |
847 | complete operating system; when you use @value{GDBN} as a remote |
848 | debugger attached to a bare board, there may not be any notion of | |
849 | ``process'', and there is often no way to get a core dump. @value{GDBN} | |
850 | will warn you if it is unable to attach or to read core dumps. | |
c906108c | 851 | |
aa26fa3a TT |
852 | You can optionally have @code{@value{GDBP}} pass any arguments after the |
853 | executable file to the inferior using @code{--args}. This option stops | |
854 | option processing. | |
855 | @example | |
856 | gdb --args gcc -O2 -c foo.c | |
857 | @end example | |
858 | This will cause @code{@value{GDBP}} to debug @code{gcc}, and to set | |
859 | @code{gcc}'s command-line arguments (@pxref{Arguments}) to @samp{-O2 -c foo.c}. | |
860 | ||
96a2c332 | 861 | You can run @code{@value{GDBP}} without printing the front material, which describes |
c906108c SS |
862 | @value{GDBN}'s non-warranty, by specifying @code{-silent}: |
863 | ||
864 | @smallexample | |
865 | @value{GDBP} -silent | |
866 | @end smallexample | |
867 | ||
868 | @noindent | |
869 | You can further control how @value{GDBN} starts up by using command-line | |
870 | options. @value{GDBN} itself can remind you of the options available. | |
871 | ||
872 | @noindent | |
873 | Type | |
874 | ||
875 | @example | |
876 | @value{GDBP} -help | |
877 | @end example | |
878 | ||
879 | @noindent | |
880 | to display all available options and briefly describe their use | |
881 | (@samp{@value{GDBP} -h} is a shorter equivalent). | |
882 | ||
883 | All options and command line arguments you give are processed | |
884 | in sequential order. The order makes a difference when the | |
885 | @samp{-x} option is used. | |
886 | ||
887 | ||
888 | @menu | |
c906108c SS |
889 | * File Options:: Choosing files |
890 | * Mode Options:: Choosing modes | |
891 | @end menu | |
892 | ||
6d2ebf8b | 893 | @node File Options |
c906108c SS |
894 | @subsection Choosing files |
895 | ||
2df3850c | 896 | When @value{GDBN} starts, it reads any arguments other than options as |
c906108c SS |
897 | specifying an executable file and core file (or process ID). This is |
898 | the same as if the arguments were specified by the @samp{-se} and | |
19837790 MS |
899 | @samp{-c} (or @samp{-p} options respectively. (@value{GDBN} reads the |
900 | first argument that does not have an associated option flag as | |
901 | equivalent to the @samp{-se} option followed by that argument; and the | |
902 | second argument that does not have an associated option flag, if any, as | |
903 | equivalent to the @samp{-c}/@samp{-p} option followed by that argument.) | |
904 | If the second argument begins with a decimal digit, @value{GDBN} will | |
905 | first attempt to attach to it as a process, and if that fails, attempt | |
906 | to open it as a corefile. If you have a corefile whose name begins with | |
907 | a digit, you can prevent @value{GDBN} from treating it as a pid by | |
79f12247 | 908 | prefixing it with @file{./}, eg. @file{./12345}. |
7a292a7a SS |
909 | |
910 | If @value{GDBN} has not been configured to included core file support, | |
911 | such as for most embedded targets, then it will complain about a second | |
912 | argument and ignore it. | |
c906108c SS |
913 | |
914 | Many options have both long and short forms; both are shown in the | |
915 | following list. @value{GDBN} also recognizes the long forms if you truncate | |
916 | them, so long as enough of the option is present to be unambiguous. | |
917 | (If you prefer, you can flag option arguments with @samp{--} rather | |
918 | than @samp{-}, though we illustrate the more usual convention.) | |
919 | ||
d700128c EZ |
920 | @c NOTE: the @cindex entries here use double dashes ON PURPOSE. This |
921 | @c way, both those who look for -foo and --foo in the index, will find | |
922 | @c it. | |
923 | ||
c906108c SS |
924 | @table @code |
925 | @item -symbols @var{file} | |
926 | @itemx -s @var{file} | |
d700128c EZ |
927 | @cindex @code{--symbols} |
928 | @cindex @code{-s} | |
c906108c SS |
929 | Read symbol table from file @var{file}. |
930 | ||
931 | @item -exec @var{file} | |
932 | @itemx -e @var{file} | |
d700128c EZ |
933 | @cindex @code{--exec} |
934 | @cindex @code{-e} | |
7a292a7a SS |
935 | Use file @var{file} as the executable file to execute when appropriate, |
936 | and for examining pure data in conjunction with a core dump. | |
c906108c SS |
937 | |
938 | @item -se @var{file} | |
d700128c | 939 | @cindex @code{--se} |
c906108c SS |
940 | Read symbol table from file @var{file} and use it as the executable |
941 | file. | |
942 | ||
c906108c SS |
943 | @item -core @var{file} |
944 | @itemx -c @var{file} | |
d700128c EZ |
945 | @cindex @code{--core} |
946 | @cindex @code{-c} | |
19837790 | 947 | Use file @var{file} as a core dump to examine. |
c906108c SS |
948 | |
949 | @item -c @var{number} | |
19837790 MS |
950 | @item -pid @var{number} |
951 | @itemx -p @var{number} | |
952 | @cindex @code{--pid} | |
953 | @cindex @code{-p} | |
954 | Connect to process ID @var{number}, as with the @code{attach} command. | |
955 | If there is no such process, @value{GDBN} will attempt to open a core | |
956 | file named @var{number}. | |
c906108c SS |
957 | |
958 | @item -command @var{file} | |
959 | @itemx -x @var{file} | |
d700128c EZ |
960 | @cindex @code{--command} |
961 | @cindex @code{-x} | |
c906108c SS |
962 | Execute @value{GDBN} commands from file @var{file}. @xref{Command |
963 | Files,, Command files}. | |
964 | ||
965 | @item -directory @var{directory} | |
966 | @itemx -d @var{directory} | |
d700128c EZ |
967 | @cindex @code{--directory} |
968 | @cindex @code{-d} | |
c906108c SS |
969 | Add @var{directory} to the path to search for source files. |
970 | ||
c906108c SS |
971 | @item -m |
972 | @itemx -mapped | |
d700128c EZ |
973 | @cindex @code{--mapped} |
974 | @cindex @code{-m} | |
c906108c SS |
975 | @emph{Warning: this option depends on operating system facilities that are not |
976 | supported on all systems.}@* | |
977 | If memory-mapped files are available on your system through the @code{mmap} | |
5d161b24 | 978 | system call, you can use this option |
c906108c SS |
979 | to have @value{GDBN} write the symbols from your |
980 | program into a reusable file in the current directory. If the program you are debugging is | |
96a2c332 | 981 | called @file{/tmp/fred}, the mapped symbol file is @file{/tmp/fred.syms}. |
c906108c SS |
982 | Future @value{GDBN} debugging sessions notice the presence of this file, |
983 | and can quickly map in symbol information from it, rather than reading | |
984 | the symbol table from the executable program. | |
985 | ||
986 | The @file{.syms} file is specific to the host machine where @value{GDBN} | |
987 | is run. It holds an exact image of the internal @value{GDBN} symbol | |
988 | table. It cannot be shared across multiple host platforms. | |
c906108c | 989 | |
c906108c SS |
990 | @item -r |
991 | @itemx -readnow | |
d700128c EZ |
992 | @cindex @code{--readnow} |
993 | @cindex @code{-r} | |
c906108c SS |
994 | Read each symbol file's entire symbol table immediately, rather than |
995 | the default, which is to read it incrementally as it is needed. | |
996 | This makes startup slower, but makes future operations faster. | |
53a5351d | 997 | |
c906108c SS |
998 | @end table |
999 | ||
2df3850c | 1000 | You typically combine the @code{-mapped} and @code{-readnow} options in |
c906108c | 1001 | order to build a @file{.syms} file that contains complete symbol |
2df3850c JM |
1002 | information. (@xref{Files,,Commands to specify files}, for information |
1003 | on @file{.syms} files.) A simple @value{GDBN} invocation to do nothing | |
1004 | but build a @file{.syms} file for future use is: | |
c906108c SS |
1005 | |
1006 | @example | |
2df3850c | 1007 | gdb -batch -nx -mapped -readnow programname |
c906108c | 1008 | @end example |
c906108c | 1009 | |
6d2ebf8b | 1010 | @node Mode Options |
c906108c SS |
1011 | @subsection Choosing modes |
1012 | ||
1013 | You can run @value{GDBN} in various alternative modes---for example, in | |
1014 | batch mode or quiet mode. | |
1015 | ||
1016 | @table @code | |
1017 | @item -nx | |
1018 | @itemx -n | |
d700128c EZ |
1019 | @cindex @code{--nx} |
1020 | @cindex @code{-n} | |
96565e91 | 1021 | Do not execute commands found in any initialization files. Normally, |
2df3850c JM |
1022 | @value{GDBN} executes the commands in these files after all the command |
1023 | options and arguments have been processed. @xref{Command Files,,Command | |
1024 | files}. | |
c906108c SS |
1025 | |
1026 | @item -quiet | |
d700128c | 1027 | @itemx -silent |
c906108c | 1028 | @itemx -q |
d700128c EZ |
1029 | @cindex @code{--quiet} |
1030 | @cindex @code{--silent} | |
1031 | @cindex @code{-q} | |
c906108c SS |
1032 | ``Quiet''. Do not print the introductory and copyright messages. These |
1033 | messages are also suppressed in batch mode. | |
1034 | ||
1035 | @item -batch | |
d700128c | 1036 | @cindex @code{--batch} |
c906108c SS |
1037 | Run in batch mode. Exit with status @code{0} after processing all the |
1038 | command files specified with @samp{-x} (and all commands from | |
1039 | initialization files, if not inhibited with @samp{-n}). Exit with | |
1040 | nonzero status if an error occurs in executing the @value{GDBN} commands | |
1041 | in the command files. | |
1042 | ||
2df3850c JM |
1043 | Batch mode may be useful for running @value{GDBN} as a filter, for |
1044 | example to download and run a program on another computer; in order to | |
1045 | make this more useful, the message | |
c906108c SS |
1046 | |
1047 | @example | |
1048 | Program exited normally. | |
1049 | @end example | |
1050 | ||
1051 | @noindent | |
2df3850c JM |
1052 | (which is ordinarily issued whenever a program running under |
1053 | @value{GDBN} control terminates) is not issued when running in batch | |
1054 | mode. | |
1055 | ||
1056 | @item -nowindows | |
1057 | @itemx -nw | |
d700128c EZ |
1058 | @cindex @code{--nowindows} |
1059 | @cindex @code{-nw} | |
2df3850c | 1060 | ``No windows''. If @value{GDBN} comes with a graphical user interface |
96a2c332 | 1061 | (GUI) built in, then this option tells @value{GDBN} to only use the command-line |
2df3850c JM |
1062 | interface. If no GUI is available, this option has no effect. |
1063 | ||
1064 | @item -windows | |
1065 | @itemx -w | |
d700128c EZ |
1066 | @cindex @code{--windows} |
1067 | @cindex @code{-w} | |
2df3850c JM |
1068 | If @value{GDBN} includes a GUI, then this option requires it to be |
1069 | used if possible. | |
c906108c SS |
1070 | |
1071 | @item -cd @var{directory} | |
d700128c | 1072 | @cindex @code{--cd} |
c906108c SS |
1073 | Run @value{GDBN} using @var{directory} as its working directory, |
1074 | instead of the current directory. | |
1075 | ||
c906108c SS |
1076 | @item -fullname |
1077 | @itemx -f | |
d700128c EZ |
1078 | @cindex @code{--fullname} |
1079 | @cindex @code{-f} | |
7a292a7a SS |
1080 | @sc{gnu} Emacs sets this option when it runs @value{GDBN} as a |
1081 | subprocess. It tells @value{GDBN} to output the full file name and line | |
1082 | number in a standard, recognizable fashion each time a stack frame is | |
1083 | displayed (which includes each time your program stops). This | |
1084 | recognizable format looks like two @samp{\032} characters, followed by | |
1085 | the file name, line number and character position separated by colons, | |
1086 | and a newline. The Emacs-to-@value{GDBN} interface program uses the two | |
1087 | @samp{\032} characters as a signal to display the source code for the | |
1088 | frame. | |
c906108c | 1089 | |
d700128c EZ |
1090 | @item -epoch |
1091 | @cindex @code{--epoch} | |
1092 | The Epoch Emacs-@value{GDBN} interface sets this option when it runs | |
1093 | @value{GDBN} as a subprocess. It tells @value{GDBN} to modify its print | |
1094 | routines so as to allow Epoch to display values of expressions in a | |
1095 | separate window. | |
1096 | ||
1097 | @item -annotate @var{level} | |
1098 | @cindex @code{--annotate} | |
1099 | This option sets the @dfn{annotation level} inside @value{GDBN}. Its | |
1100 | effect is identical to using @samp{set annotate @var{level}} | |
1101 | (@pxref{Annotations}). | |
1102 | Annotation level controls how much information does @value{GDBN} print | |
1103 | together with its prompt, values of expressions, source lines, and other | |
1104 | types of output. Level 0 is the normal, level 1 is for use when | |
1105 | @value{GDBN} is run as a subprocess of @sc{gnu} Emacs, level 2 is the | |
1106 | maximum annotation suitable for programs that control @value{GDBN}. | |
1107 | ||
1108 | @item -async | |
1109 | @cindex @code{--async} | |
1110 | Use the asynchronous event loop for the command-line interface. | |
1111 | @value{GDBN} processes all events, such as user keyboard input, via a | |
1112 | special event loop. This allows @value{GDBN} to accept and process user | |
1113 | commands in parallel with the debugged process being | |
1114 | run@footnote{@value{GDBN} built with @sc{djgpp} tools for | |
1115 | MS-DOS/MS-Windows supports this mode of operation, but the event loop is | |
1116 | suspended when the debuggee runs.}, so you don't need to wait for | |
1117 | control to return to @value{GDBN} before you type the next command. | |
b37052ae | 1118 | (@emph{Note:} as of version 5.1, the target side of the asynchronous |
d700128c EZ |
1119 | operation is not yet in place, so @samp{-async} does not work fully |
1120 | yet.) | |
1121 | @c FIXME: when the target side of the event loop is done, the above NOTE | |
1122 | @c should be removed. | |
1123 | ||
1124 | When the standard input is connected to a terminal device, @value{GDBN} | |
1125 | uses the asynchronous event loop by default, unless disabled by the | |
1126 | @samp{-noasync} option. | |
1127 | ||
1128 | @item -noasync | |
1129 | @cindex @code{--noasync} | |
1130 | Disable the asynchronous event loop for the command-line interface. | |
1131 | ||
aa26fa3a TT |
1132 | @item --args |
1133 | @cindex @code{--args} | |
1134 | Change interpretation of command line so that arguments following the | |
1135 | executable file are passed as command line arguments to the inferior. | |
1136 | This option stops option processing. | |
1137 | ||
2df3850c JM |
1138 | @item -baud @var{bps} |
1139 | @itemx -b @var{bps} | |
d700128c EZ |
1140 | @cindex @code{--baud} |
1141 | @cindex @code{-b} | |
c906108c SS |
1142 | Set the line speed (baud rate or bits per second) of any serial |
1143 | interface used by @value{GDBN} for remote debugging. | |
c906108c SS |
1144 | |
1145 | @item -tty @var{device} | |
d700128c EZ |
1146 | @itemx -t @var{device} |
1147 | @cindex @code{--tty} | |
1148 | @cindex @code{-t} | |
c906108c SS |
1149 | Run using @var{device} for your program's standard input and output. |
1150 | @c FIXME: kingdon thinks there is more to -tty. Investigate. | |
c906108c | 1151 | |
53a5351d | 1152 | @c resolve the situation of these eventually |
c4555f82 SC |
1153 | @item -tui |
1154 | @cindex @code{--tui} | |
1155 | Activate the Terminal User Interface when starting. | |
1156 | The Terminal User Interface manages several text windows on the terminal, | |
1157 | showing source, assembly, registers and @value{GDBN} command outputs | |
1158 | (@pxref{TUI, ,@value{GDBN} Text User Interface}). | |
1159 | Do not use this option if you run @value{GDBN} from Emacs | |
1160 | (@pxref{Emacs, ,Using @value{GDBN} under @sc{gnu} Emacs}). | |
53a5351d JM |
1161 | |
1162 | @c @item -xdb | |
d700128c | 1163 | @c @cindex @code{--xdb} |
53a5351d JM |
1164 | @c Run in XDB compatibility mode, allowing the use of certain XDB commands. |
1165 | @c For information, see the file @file{xdb_trans.html}, which is usually | |
1166 | @c installed in the directory @code{/opt/langtools/wdb/doc} on HP-UX | |
1167 | @c systems. | |
1168 | ||
d700128c EZ |
1169 | @item -interpreter @var{interp} |
1170 | @cindex @code{--interpreter} | |
1171 | Use the interpreter @var{interp} for interface with the controlling | |
1172 | program or device. This option is meant to be set by programs which | |
94bbb2c0 AC |
1173 | communicate with @value{GDBN} using it as a back end. |
1174 | ||
1175 | @samp{--interpreter=mi} (or @samp{--interpreter=mi1}) causes | |
1176 | @value{GDBN} to use the @dfn{gdb/mi interface} (@pxref{GDB/MI, , The | |
1177 | @sc{gdb/mi} Interface}). The older @sc{gdb/mi} interface, included in | |
1178 | @value{GDBN} version 5.0 can be selected with @samp{--interpreter=mi0}. | |
d700128c EZ |
1179 | |
1180 | @item -write | |
1181 | @cindex @code{--write} | |
1182 | Open the executable and core files for both reading and writing. This | |
1183 | is equivalent to the @samp{set write on} command inside @value{GDBN} | |
1184 | (@pxref{Patching}). | |
1185 | ||
1186 | @item -statistics | |
1187 | @cindex @code{--statistics} | |
1188 | This option causes @value{GDBN} to print statistics about time and | |
1189 | memory usage after it completes each command and returns to the prompt. | |
1190 | ||
1191 | @item -version | |
1192 | @cindex @code{--version} | |
1193 | This option causes @value{GDBN} to print its version number and | |
1194 | no-warranty blurb, and exit. | |
1195 | ||
c906108c SS |
1196 | @end table |
1197 | ||
6d2ebf8b | 1198 | @node Quitting GDB |
c906108c SS |
1199 | @section Quitting @value{GDBN} |
1200 | @cindex exiting @value{GDBN} | |
1201 | @cindex leaving @value{GDBN} | |
1202 | ||
1203 | @table @code | |
1204 | @kindex quit @r{[}@var{expression}@r{]} | |
41afff9a | 1205 | @kindex q @r{(@code{quit})} |
96a2c332 SS |
1206 | @item quit @r{[}@var{expression}@r{]} |
1207 | @itemx q | |
1208 | To exit @value{GDBN}, use the @code{quit} command (abbreviated | |
1209 | @code{q}), or type an end-of-file character (usually @kbd{C-d}). If you | |
1210 | do not supply @var{expression}, @value{GDBN} will terminate normally; | |
1211 | otherwise it will terminate using the result of @var{expression} as the | |
1212 | error code. | |
c906108c SS |
1213 | @end table |
1214 | ||
1215 | @cindex interrupt | |
1216 | An interrupt (often @kbd{C-c}) does not exit from @value{GDBN}, but rather | |
1217 | terminates the action of any @value{GDBN} command that is in progress and | |
1218 | returns to @value{GDBN} command level. It is safe to type the interrupt | |
1219 | character at any time because @value{GDBN} does not allow it to take effect | |
1220 | until a time when it is safe. | |
1221 | ||
c906108c SS |
1222 | If you have been using @value{GDBN} to control an attached process or |
1223 | device, you can release it with the @code{detach} command | |
1224 | (@pxref{Attach, ,Debugging an already-running process}). | |
c906108c | 1225 | |
6d2ebf8b | 1226 | @node Shell Commands |
c906108c SS |
1227 | @section Shell commands |
1228 | ||
1229 | If you need to execute occasional shell commands during your | |
1230 | debugging session, there is no need to leave or suspend @value{GDBN}; you can | |
1231 | just use the @code{shell} command. | |
1232 | ||
1233 | @table @code | |
1234 | @kindex shell | |
1235 | @cindex shell escape | |
1236 | @item shell @var{command string} | |
1237 | Invoke a standard shell to execute @var{command string}. | |
c906108c | 1238 | If it exists, the environment variable @code{SHELL} determines which |
d4f3574e SS |
1239 | shell to run. Otherwise @value{GDBN} uses the default shell |
1240 | (@file{/bin/sh} on Unix systems, @file{COMMAND.COM} on MS-DOS, etc.). | |
c906108c SS |
1241 | @end table |
1242 | ||
1243 | The utility @code{make} is often needed in development environments. | |
1244 | You do not have to use the @code{shell} command for this purpose in | |
1245 | @value{GDBN}: | |
1246 | ||
1247 | @table @code | |
1248 | @kindex make | |
1249 | @cindex calling make | |
1250 | @item make @var{make-args} | |
1251 | Execute the @code{make} program with the specified | |
1252 | arguments. This is equivalent to @samp{shell make @var{make-args}}. | |
1253 | @end table | |
1254 | ||
6d2ebf8b | 1255 | @node Commands |
c906108c SS |
1256 | @chapter @value{GDBN} Commands |
1257 | ||
1258 | You can abbreviate a @value{GDBN} command to the first few letters of the command | |
1259 | name, if that abbreviation is unambiguous; and you can repeat certain | |
1260 | @value{GDBN} commands by typing just @key{RET}. You can also use the @key{TAB} | |
1261 | key to get @value{GDBN} to fill out the rest of a word in a command (or to | |
1262 | show you the alternatives available, if there is more than one possibility). | |
1263 | ||
1264 | @menu | |
1265 | * Command Syntax:: How to give commands to @value{GDBN} | |
1266 | * Completion:: Command completion | |
1267 | * Help:: How to ask @value{GDBN} for help | |
1268 | @end menu | |
1269 | ||
6d2ebf8b | 1270 | @node Command Syntax |
c906108c SS |
1271 | @section Command syntax |
1272 | ||
1273 | A @value{GDBN} command is a single line of input. There is no limit on | |
1274 | how long it can be. It starts with a command name, which is followed by | |
1275 | arguments whose meaning depends on the command name. For example, the | |
1276 | command @code{step} accepts an argument which is the number of times to | |
1277 | step, as in @samp{step 5}. You can also use the @code{step} command | |
96a2c332 | 1278 | with no arguments. Some commands do not allow any arguments. |
c906108c SS |
1279 | |
1280 | @cindex abbreviation | |
1281 | @value{GDBN} command names may always be truncated if that abbreviation is | |
1282 | unambiguous. Other possible command abbreviations are listed in the | |
1283 | documentation for individual commands. In some cases, even ambiguous | |
1284 | abbreviations are allowed; for example, @code{s} is specially defined as | |
1285 | equivalent to @code{step} even though there are other commands whose | |
1286 | names start with @code{s}. You can test abbreviations by using them as | |
1287 | arguments to the @code{help} command. | |
1288 | ||
1289 | @cindex repeating commands | |
41afff9a | 1290 | @kindex RET @r{(repeat last command)} |
c906108c | 1291 | A blank line as input to @value{GDBN} (typing just @key{RET}) means to |
96a2c332 | 1292 | repeat the previous command. Certain commands (for example, @code{run}) |
c906108c SS |
1293 | will not repeat this way; these are commands whose unintentional |
1294 | repetition might cause trouble and which you are unlikely to want to | |
1295 | repeat. | |
1296 | ||
1297 | The @code{list} and @code{x} commands, when you repeat them with | |
1298 | @key{RET}, construct new arguments rather than repeating | |
1299 | exactly as typed. This permits easy scanning of source or memory. | |
1300 | ||
1301 | @value{GDBN} can also use @key{RET} in another way: to partition lengthy | |
1302 | output, in a way similar to the common utility @code{more} | |
1303 | (@pxref{Screen Size,,Screen size}). Since it is easy to press one | |
1304 | @key{RET} too many in this situation, @value{GDBN} disables command | |
1305 | repetition after any command that generates this sort of display. | |
1306 | ||
41afff9a | 1307 | @kindex # @r{(a comment)} |
c906108c SS |
1308 | @cindex comment |
1309 | Any text from a @kbd{#} to the end of the line is a comment; it does | |
1310 | nothing. This is useful mainly in command files (@pxref{Command | |
1311 | Files,,Command files}). | |
1312 | ||
88118b3a TT |
1313 | @cindex repeating command sequences |
1314 | @kindex C-o @r{(operate-and-get-next)} | |
1315 | The @kbd{C-o} binding is useful for repeating a complex sequence of | |
1316 | commands. This command accepts the current line, like @kbd{RET}, and | |
1317 | then fetches the next line relative to the current line from the history | |
1318 | for editing. | |
1319 | ||
6d2ebf8b | 1320 | @node Completion |
c906108c SS |
1321 | @section Command completion |
1322 | ||
1323 | @cindex completion | |
1324 | @cindex word completion | |
1325 | @value{GDBN} can fill in the rest of a word in a command for you, if there is | |
1326 | only one possibility; it can also show you what the valid possibilities | |
1327 | are for the next word in a command, at any time. This works for @value{GDBN} | |
1328 | commands, @value{GDBN} subcommands, and the names of symbols in your program. | |
1329 | ||
1330 | Press the @key{TAB} key whenever you want @value{GDBN} to fill out the rest | |
1331 | of a word. If there is only one possibility, @value{GDBN} fills in the | |
1332 | word, and waits for you to finish the command (or press @key{RET} to | |
1333 | enter it). For example, if you type | |
1334 | ||
1335 | @c FIXME "@key" does not distinguish its argument sufficiently to permit | |
1336 | @c complete accuracy in these examples; space introduced for clarity. | |
1337 | @c If texinfo enhancements make it unnecessary, it would be nice to | |
1338 | @c replace " @key" by "@key" in the following... | |
1339 | @example | |
1340 | (@value{GDBP}) info bre @key{TAB} | |
1341 | @end example | |
1342 | ||
1343 | @noindent | |
1344 | @value{GDBN} fills in the rest of the word @samp{breakpoints}, since that is | |
1345 | the only @code{info} subcommand beginning with @samp{bre}: | |
1346 | ||
1347 | @example | |
1348 | (@value{GDBP}) info breakpoints | |
1349 | @end example | |
1350 | ||
1351 | @noindent | |
1352 | You can either press @key{RET} at this point, to run the @code{info | |
1353 | breakpoints} command, or backspace and enter something else, if | |
1354 | @samp{breakpoints} does not look like the command you expected. (If you | |
1355 | were sure you wanted @code{info breakpoints} in the first place, you | |
1356 | might as well just type @key{RET} immediately after @samp{info bre}, | |
1357 | to exploit command abbreviations rather than command completion). | |
1358 | ||
1359 | If there is more than one possibility for the next word when you press | |
1360 | @key{TAB}, @value{GDBN} sounds a bell. You can either supply more | |
1361 | characters and try again, or just press @key{TAB} a second time; | |
1362 | @value{GDBN} displays all the possible completions for that word. For | |
1363 | example, you might want to set a breakpoint on a subroutine whose name | |
1364 | begins with @samp{make_}, but when you type @kbd{b make_@key{TAB}} @value{GDBN} | |
1365 | just sounds the bell. Typing @key{TAB} again displays all the | |
1366 | function names in your program that begin with those characters, for | |
1367 | example: | |
1368 | ||
1369 | @example | |
1370 | (@value{GDBP}) b make_ @key{TAB} | |
1371 | @exdent @value{GDBN} sounds bell; press @key{TAB} again, to see: | |
5d161b24 DB |
1372 | make_a_section_from_file make_environ |
1373 | make_abs_section make_function_type | |
1374 | make_blockvector make_pointer_type | |
1375 | make_cleanup make_reference_type | |
c906108c SS |
1376 | make_command make_symbol_completion_list |
1377 | (@value{GDBP}) b make_ | |
1378 | @end example | |
1379 | ||
1380 | @noindent | |
1381 | After displaying the available possibilities, @value{GDBN} copies your | |
1382 | partial input (@samp{b make_} in the example) so you can finish the | |
1383 | command. | |
1384 | ||
1385 | If you just want to see the list of alternatives in the first place, you | |
b37052ae | 1386 | can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?} |
7a292a7a | 1387 | means @kbd{@key{META} ?}. You can type this either by holding down a |
c906108c | 1388 | key designated as the @key{META} shift on your keyboard (if there is |
7a292a7a | 1389 | one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}. |
c906108c SS |
1390 | |
1391 | @cindex quotes in commands | |
1392 | @cindex completion of quoted strings | |
1393 | Sometimes the string you need, while logically a ``word'', may contain | |
7a292a7a SS |
1394 | parentheses or other characters that @value{GDBN} normally excludes from |
1395 | its notion of a word. To permit word completion to work in this | |
1396 | situation, you may enclose words in @code{'} (single quote marks) in | |
1397 | @value{GDBN} commands. | |
c906108c | 1398 | |
c906108c | 1399 | The most likely situation where you might need this is in typing the |
b37052ae EZ |
1400 | name of a C@t{++} function. This is because C@t{++} allows function |
1401 | overloading (multiple definitions of the same function, distinguished | |
1402 | by argument type). For example, when you want to set a breakpoint you | |
1403 | may need to distinguish whether you mean the version of @code{name} | |
1404 | that takes an @code{int} parameter, @code{name(int)}, or the version | |
1405 | that takes a @code{float} parameter, @code{name(float)}. To use the | |
1406 | word-completion facilities in this situation, type a single quote | |
1407 | @code{'} at the beginning of the function name. This alerts | |
1408 | @value{GDBN} that it may need to consider more information than usual | |
1409 | when you press @key{TAB} or @kbd{M-?} to request word completion: | |
c906108c SS |
1410 | |
1411 | @example | |
96a2c332 | 1412 | (@value{GDBP}) b 'bubble( @kbd{M-?} |
c906108c SS |
1413 | bubble(double,double) bubble(int,int) |
1414 | (@value{GDBP}) b 'bubble( | |
1415 | @end example | |
1416 | ||
1417 | In some cases, @value{GDBN} can tell that completing a name requires using | |
1418 | quotes. When this happens, @value{GDBN} inserts the quote for you (while | |
1419 | completing as much as it can) if you do not type the quote in the first | |
1420 | place: | |
1421 | ||
1422 | @example | |
1423 | (@value{GDBP}) b bub @key{TAB} | |
1424 | @exdent @value{GDBN} alters your input line to the following, and rings a bell: | |
1425 | (@value{GDBP}) b 'bubble( | |
1426 | @end example | |
1427 | ||
1428 | @noindent | |
1429 | In general, @value{GDBN} can tell that a quote is needed (and inserts it) if | |
1430 | you have not yet started typing the argument list when you ask for | |
1431 | completion on an overloaded symbol. | |
1432 | ||
d4f3574e | 1433 | For more information about overloaded functions, see @ref{C plus plus |
b37052ae | 1434 | expressions, ,C@t{++} expressions}. You can use the command @code{set |
c906108c | 1435 | overload-resolution off} to disable overload resolution; |
b37052ae | 1436 | see @ref{Debugging C plus plus, ,@value{GDBN} features for C@t{++}}. |
c906108c SS |
1437 | |
1438 | ||
6d2ebf8b | 1439 | @node Help |
c906108c SS |
1440 | @section Getting help |
1441 | @cindex online documentation | |
1442 | @kindex help | |
1443 | ||
5d161b24 | 1444 | You can always ask @value{GDBN} itself for information on its commands, |
c906108c SS |
1445 | using the command @code{help}. |
1446 | ||
1447 | @table @code | |
41afff9a | 1448 | @kindex h @r{(@code{help})} |
c906108c SS |
1449 | @item help |
1450 | @itemx h | |
1451 | You can use @code{help} (abbreviated @code{h}) with no arguments to | |
1452 | display a short list of named classes of commands: | |
1453 | ||
1454 | @smallexample | |
1455 | (@value{GDBP}) help | |
1456 | List of classes of commands: | |
1457 | ||
2df3850c | 1458 | aliases -- Aliases of other commands |
c906108c | 1459 | breakpoints -- Making program stop at certain points |
2df3850c | 1460 | data -- Examining data |
c906108c | 1461 | files -- Specifying and examining files |
2df3850c JM |
1462 | internals -- Maintenance commands |
1463 | obscure -- Obscure features | |
1464 | running -- Running the program | |
1465 | stack -- Examining the stack | |
c906108c SS |
1466 | status -- Status inquiries |
1467 | support -- Support facilities | |
96a2c332 SS |
1468 | tracepoints -- Tracing of program execution without@* |
1469 | stopping the program | |
c906108c | 1470 | user-defined -- User-defined commands |
c906108c | 1471 | |
5d161b24 | 1472 | Type "help" followed by a class name for a list of |
c906108c | 1473 | commands in that class. |
5d161b24 | 1474 | Type "help" followed by command name for full |
c906108c SS |
1475 | documentation. |
1476 | Command name abbreviations are allowed if unambiguous. | |
1477 | (@value{GDBP}) | |
1478 | @end smallexample | |
96a2c332 | 1479 | @c the above line break eliminates huge line overfull... |
c906108c SS |
1480 | |
1481 | @item help @var{class} | |
1482 | Using one of the general help classes as an argument, you can get a | |
1483 | list of the individual commands in that class. For example, here is the | |
1484 | help display for the class @code{status}: | |
1485 | ||
1486 | @smallexample | |
1487 | (@value{GDBP}) help status | |
1488 | Status inquiries. | |
1489 | ||
1490 | List of commands: | |
1491 | ||
1492 | @c Line break in "show" line falsifies real output, but needed | |
1493 | @c to fit in smallbook page size. | |
2df3850c JM |
1494 | info -- Generic command for showing things |
1495 | about the program being debugged | |
1496 | show -- Generic command for showing things | |
1497 | about the debugger | |
c906108c | 1498 | |
5d161b24 | 1499 | Type "help" followed by command name for full |
c906108c SS |
1500 | documentation. |
1501 | Command name abbreviations are allowed if unambiguous. | |
1502 | (@value{GDBP}) | |
1503 | @end smallexample | |
1504 | ||
1505 | @item help @var{command} | |
1506 | With a command name as @code{help} argument, @value{GDBN} displays a | |
1507 | short paragraph on how to use that command. | |
1508 | ||
6837a0a2 DB |
1509 | @kindex apropos |
1510 | @item apropos @var{args} | |
1511 | The @code{apropos @var{args}} command searches through all of the @value{GDBN} | |
1512 | commands, and their documentation, for the regular expression specified in | |
1513 | @var{args}. It prints out all matches found. For example: | |
1514 | ||
1515 | @smallexample | |
1516 | apropos reload | |
1517 | @end smallexample | |
1518 | ||
b37052ae EZ |
1519 | @noindent |
1520 | results in: | |
6837a0a2 DB |
1521 | |
1522 | @smallexample | |
6d2ebf8b SS |
1523 | @c @group |
1524 | set symbol-reloading -- Set dynamic symbol table reloading | |
1525 | multiple times in one run | |
1526 | show symbol-reloading -- Show dynamic symbol table reloading | |
1527 | multiple times in one run | |
1528 | @c @end group | |
6837a0a2 DB |
1529 | @end smallexample |
1530 | ||
c906108c SS |
1531 | @kindex complete |
1532 | @item complete @var{args} | |
1533 | The @code{complete @var{args}} command lists all the possible completions | |
1534 | for the beginning of a command. Use @var{args} to specify the beginning of the | |
1535 | command you want completed. For example: | |
1536 | ||
1537 | @smallexample | |
1538 | complete i | |
1539 | @end smallexample | |
1540 | ||
1541 | @noindent results in: | |
1542 | ||
1543 | @smallexample | |
1544 | @group | |
2df3850c JM |
1545 | if |
1546 | ignore | |
c906108c SS |
1547 | info |
1548 | inspect | |
c906108c SS |
1549 | @end group |
1550 | @end smallexample | |
1551 | ||
1552 | @noindent This is intended for use by @sc{gnu} Emacs. | |
1553 | @end table | |
1554 | ||
1555 | In addition to @code{help}, you can use the @value{GDBN} commands @code{info} | |
1556 | and @code{show} to inquire about the state of your program, or the state | |
1557 | of @value{GDBN} itself. Each command supports many topics of inquiry; this | |
1558 | manual introduces each of them in the appropriate context. The listings | |
1559 | under @code{info} and under @code{show} in the Index point to | |
1560 | all the sub-commands. @xref{Index}. | |
1561 | ||
1562 | @c @group | |
1563 | @table @code | |
1564 | @kindex info | |
41afff9a | 1565 | @kindex i @r{(@code{info})} |
c906108c SS |
1566 | @item info |
1567 | This command (abbreviated @code{i}) is for describing the state of your | |
1568 | program. For example, you can list the arguments given to your program | |
1569 | with @code{info args}, list the registers currently in use with @code{info | |
1570 | registers}, or list the breakpoints you have set with @code{info breakpoints}. | |
1571 | You can get a complete list of the @code{info} sub-commands with | |
1572 | @w{@code{help info}}. | |
1573 | ||
1574 | @kindex set | |
1575 | @item set | |
5d161b24 | 1576 | You can assign the result of an expression to an environment variable with |
c906108c SS |
1577 | @code{set}. For example, you can set the @value{GDBN} prompt to a $-sign with |
1578 | @code{set prompt $}. | |
1579 | ||
1580 | @kindex show | |
1581 | @item show | |
5d161b24 | 1582 | In contrast to @code{info}, @code{show} is for describing the state of |
c906108c SS |
1583 | @value{GDBN} itself. |
1584 | You can change most of the things you can @code{show}, by using the | |
1585 | related command @code{set}; for example, you can control what number | |
1586 | system is used for displays with @code{set radix}, or simply inquire | |
1587 | which is currently in use with @code{show radix}. | |
1588 | ||
1589 | @kindex info set | |
1590 | To display all the settable parameters and their current | |
1591 | values, you can use @code{show} with no arguments; you may also use | |
1592 | @code{info set}. Both commands produce the same display. | |
1593 | @c FIXME: "info set" violates the rule that "info" is for state of | |
1594 | @c FIXME...program. Ck w/ GNU: "info set" to be called something else, | |
1595 | @c FIXME...or change desc of rule---eg "state of prog and debugging session"? | |
1596 | @end table | |
1597 | @c @end group | |
1598 | ||
1599 | Here are three miscellaneous @code{show} subcommands, all of which are | |
1600 | exceptional in lacking corresponding @code{set} commands: | |
1601 | ||
1602 | @table @code | |
1603 | @kindex show version | |
1604 | @cindex version number | |
1605 | @item show version | |
1606 | Show what version of @value{GDBN} is running. You should include this | |
2df3850c JM |
1607 | information in @value{GDBN} bug-reports. If multiple versions of |
1608 | @value{GDBN} are in use at your site, you may need to determine which | |
1609 | version of @value{GDBN} you are running; as @value{GDBN} evolves, new | |
1610 | commands are introduced, and old ones may wither away. Also, many | |
1611 | system vendors ship variant versions of @value{GDBN}, and there are | |
96a2c332 | 1612 | variant versions of @value{GDBN} in @sc{gnu}/Linux distributions as well. |
2df3850c JM |
1613 | The version number is the same as the one announced when you start |
1614 | @value{GDBN}. | |
c906108c SS |
1615 | |
1616 | @kindex show copying | |
1617 | @item show copying | |
1618 | Display information about permission for copying @value{GDBN}. | |
1619 | ||
1620 | @kindex show warranty | |
1621 | @item show warranty | |
2df3850c | 1622 | Display the @sc{gnu} ``NO WARRANTY'' statement, or a warranty, |
96a2c332 | 1623 | if your version of @value{GDBN} comes with one. |
2df3850c | 1624 | |
c906108c SS |
1625 | @end table |
1626 | ||
6d2ebf8b | 1627 | @node Running |
c906108c SS |
1628 | @chapter Running Programs Under @value{GDBN} |
1629 | ||
1630 | When you run a program under @value{GDBN}, you must first generate | |
1631 | debugging information when you compile it. | |
7a292a7a SS |
1632 | |
1633 | You may start @value{GDBN} with its arguments, if any, in an environment | |
1634 | of your choice. If you are doing native debugging, you may redirect | |
1635 | your program's input and output, debug an already running process, or | |
1636 | kill a child process. | |
c906108c SS |
1637 | |
1638 | @menu | |
1639 | * Compilation:: Compiling for debugging | |
1640 | * Starting:: Starting your program | |
c906108c SS |
1641 | * Arguments:: Your program's arguments |
1642 | * Environment:: Your program's environment | |
c906108c SS |
1643 | |
1644 | * Working Directory:: Your program's working directory | |
1645 | * Input/Output:: Your program's input and output | |
1646 | * Attach:: Debugging an already-running process | |
1647 | * Kill Process:: Killing the child process | |
c906108c SS |
1648 | |
1649 | * Threads:: Debugging programs with multiple threads | |
1650 | * Processes:: Debugging programs with multiple processes | |
1651 | @end menu | |
1652 | ||
6d2ebf8b | 1653 | @node Compilation |
c906108c SS |
1654 | @section Compiling for debugging |
1655 | ||
1656 | In order to debug a program effectively, you need to generate | |
1657 | debugging information when you compile it. This debugging information | |
1658 | is stored in the object file; it describes the data type of each | |
1659 | variable or function and the correspondence between source line numbers | |
1660 | and addresses in the executable code. | |
1661 | ||
1662 | To request debugging information, specify the @samp{-g} option when you run | |
1663 | the compiler. | |
1664 | ||
1665 | Many C compilers are unable to handle the @samp{-g} and @samp{-O} | |
1666 | options together. Using those compilers, you cannot generate optimized | |
1667 | executables containing debugging information. | |
1668 | ||
53a5351d JM |
1669 | @value{NGCC}, the @sc{gnu} C compiler, supports @samp{-g} with or |
1670 | without @samp{-O}, making it possible to debug optimized code. We | |
1671 | recommend that you @emph{always} use @samp{-g} whenever you compile a | |
1672 | program. You may think your program is correct, but there is no sense | |
1673 | in pushing your luck. | |
c906108c SS |
1674 | |
1675 | @cindex optimized code, debugging | |
1676 | @cindex debugging optimized code | |
1677 | When you debug a program compiled with @samp{-g -O}, remember that the | |
1678 | optimizer is rearranging your code; the debugger shows you what is | |
1679 | really there. Do not be too surprised when the execution path does not | |
1680 | exactly match your source file! An extreme example: if you define a | |
1681 | variable, but never use it, @value{GDBN} never sees that | |
1682 | variable---because the compiler optimizes it out of existence. | |
1683 | ||
1684 | Some things do not work as well with @samp{-g -O} as with just | |
1685 | @samp{-g}, particularly on machines with instruction scheduling. If in | |
1686 | doubt, recompile with @samp{-g} alone, and if this fixes the problem, | |
1687 | please report it to us as a bug (including a test case!). | |
1688 | ||
1689 | Older versions of the @sc{gnu} C compiler permitted a variant option | |
1690 | @w{@samp{-gg}} for debugging information. @value{GDBN} no longer supports this | |
1691 | format; if your @sc{gnu} C compiler has this option, do not use it. | |
1692 | ||
1693 | @need 2000 | |
6d2ebf8b | 1694 | @node Starting |
c906108c SS |
1695 | @section Starting your program |
1696 | @cindex starting | |
1697 | @cindex running | |
1698 | ||
1699 | @table @code | |
1700 | @kindex run | |
41afff9a | 1701 | @kindex r @r{(@code{run})} |
c906108c SS |
1702 | @item run |
1703 | @itemx r | |
7a292a7a SS |
1704 | Use the @code{run} command to start your program under @value{GDBN}. |
1705 | You must first specify the program name (except on VxWorks) with an | |
1706 | argument to @value{GDBN} (@pxref{Invocation, ,Getting In and Out of | |
1707 | @value{GDBN}}), or by using the @code{file} or @code{exec-file} command | |
1708 | (@pxref{Files, ,Commands to specify files}). | |
c906108c SS |
1709 | |
1710 | @end table | |
1711 | ||
c906108c SS |
1712 | If you are running your program in an execution environment that |
1713 | supports processes, @code{run} creates an inferior process and makes | |
1714 | that process run your program. (In environments without processes, | |
1715 | @code{run} jumps to the start of your program.) | |
1716 | ||
1717 | The execution of a program is affected by certain information it | |
1718 | receives from its superior. @value{GDBN} provides ways to specify this | |
1719 | information, which you must do @emph{before} starting your program. (You | |
1720 | can change it after starting your program, but such changes only affect | |
1721 | your program the next time you start it.) This information may be | |
1722 | divided into four categories: | |
1723 | ||
1724 | @table @asis | |
1725 | @item The @emph{arguments.} | |
1726 | Specify the arguments to give your program as the arguments of the | |
1727 | @code{run} command. If a shell is available on your target, the shell | |
1728 | is used to pass the arguments, so that you may use normal conventions | |
1729 | (such as wildcard expansion or variable substitution) in describing | |
1730 | the arguments. | |
1731 | In Unix systems, you can control which shell is used with the | |
1732 | @code{SHELL} environment variable. | |
1733 | @xref{Arguments, ,Your program's arguments}. | |
1734 | ||
1735 | @item The @emph{environment.} | |
1736 | Your program normally inherits its environment from @value{GDBN}, but you can | |
1737 | use the @value{GDBN} commands @code{set environment} and @code{unset | |
1738 | environment} to change parts of the environment that affect | |
1739 | your program. @xref{Environment, ,Your program's environment}. | |
1740 | ||
1741 | @item The @emph{working directory.} | |
1742 | Your program inherits its working directory from @value{GDBN}. You can set | |
1743 | the @value{GDBN} working directory with the @code{cd} command in @value{GDBN}. | |
1744 | @xref{Working Directory, ,Your program's working directory}. | |
1745 | ||
1746 | @item The @emph{standard input and output.} | |
1747 | Your program normally uses the same device for standard input and | |
1748 | standard output as @value{GDBN} is using. You can redirect input and output | |
1749 | in the @code{run} command line, or you can use the @code{tty} command to | |
1750 | set a different device for your program. | |
1751 | @xref{Input/Output, ,Your program's input and output}. | |
1752 | ||
1753 | @cindex pipes | |
1754 | @emph{Warning:} While input and output redirection work, you cannot use | |
1755 | pipes to pass the output of the program you are debugging to another | |
1756 | program; if you attempt this, @value{GDBN} is likely to wind up debugging the | |
1757 | wrong program. | |
1758 | @end table | |
c906108c SS |
1759 | |
1760 | When you issue the @code{run} command, your program begins to execute | |
1761 | immediately. @xref{Stopping, ,Stopping and continuing}, for discussion | |
1762 | of how to arrange for your program to stop. Once your program has | |
1763 | stopped, you may call functions in your program, using the @code{print} | |
1764 | or @code{call} commands. @xref{Data, ,Examining Data}. | |
1765 | ||
1766 | If the modification time of your symbol file has changed since the last | |
1767 | time @value{GDBN} read its symbols, @value{GDBN} discards its symbol | |
1768 | table, and reads it again. When it does this, @value{GDBN} tries to retain | |
1769 | your current breakpoints. | |
1770 | ||
6d2ebf8b | 1771 | @node Arguments |
c906108c SS |
1772 | @section Your program's arguments |
1773 | ||
1774 | @cindex arguments (to your program) | |
1775 | The arguments to your program can be specified by the arguments of the | |
5d161b24 | 1776 | @code{run} command. |
c906108c SS |
1777 | They are passed to a shell, which expands wildcard characters and |
1778 | performs redirection of I/O, and thence to your program. Your | |
1779 | @code{SHELL} environment variable (if it exists) specifies what shell | |
1780 | @value{GDBN} uses. If you do not define @code{SHELL}, @value{GDBN} uses | |
d4f3574e SS |
1781 | the default shell (@file{/bin/sh} on Unix). |
1782 | ||
1783 | On non-Unix systems, the program is usually invoked directly by | |
1784 | @value{GDBN}, which emulates I/O redirection via the appropriate system | |
1785 | calls, and the wildcard characters are expanded by the startup code of | |
1786 | the program, not by the shell. | |
c906108c SS |
1787 | |
1788 | @code{run} with no arguments uses the same arguments used by the previous | |
1789 | @code{run}, or those set by the @code{set args} command. | |
1790 | ||
c906108c | 1791 | @table @code |
41afff9a | 1792 | @kindex set args |
c906108c SS |
1793 | @item set args |
1794 | Specify the arguments to be used the next time your program is run. If | |
1795 | @code{set args} has no arguments, @code{run} executes your program | |
1796 | with no arguments. Once you have run your program with arguments, | |
1797 | using @code{set args} before the next @code{run} is the only way to run | |
1798 | it again without arguments. | |
1799 | ||
1800 | @kindex show args | |
1801 | @item show args | |
1802 | Show the arguments to give your program when it is started. | |
1803 | @end table | |
1804 | ||
6d2ebf8b | 1805 | @node Environment |
c906108c SS |
1806 | @section Your program's environment |
1807 | ||
1808 | @cindex environment (of your program) | |
1809 | The @dfn{environment} consists of a set of environment variables and | |
1810 | their values. Environment variables conventionally record such things as | |
1811 | your user name, your home directory, your terminal type, and your search | |
1812 | path for programs to run. Usually you set up environment variables with | |
1813 | the shell and they are inherited by all the other programs you run. When | |
1814 | debugging, it can be useful to try running your program with a modified | |
1815 | environment without having to start @value{GDBN} over again. | |
1816 | ||
1817 | @table @code | |
1818 | @kindex path | |
1819 | @item path @var{directory} | |
1820 | Add @var{directory} to the front of the @code{PATH} environment variable | |
17cc6a06 EZ |
1821 | (the search path for executables) that will be passed to your program. |
1822 | The value of @code{PATH} used by @value{GDBN} does not change. | |
d4f3574e SS |
1823 | You may specify several directory names, separated by whitespace or by a |
1824 | system-dependent separator character (@samp{:} on Unix, @samp{;} on | |
1825 | MS-DOS and MS-Windows). If @var{directory} is already in the path, it | |
1826 | is moved to the front, so it is searched sooner. | |
c906108c SS |
1827 | |
1828 | You can use the string @samp{$cwd} to refer to whatever is the current | |
1829 | working directory at the time @value{GDBN} searches the path. If you | |
1830 | use @samp{.} instead, it refers to the directory where you executed the | |
1831 | @code{path} command. @value{GDBN} replaces @samp{.} in the | |
1832 | @var{directory} argument (with the current path) before adding | |
1833 | @var{directory} to the search path. | |
1834 | @c 'path' is explicitly nonrepeatable, but RMS points out it is silly to | |
1835 | @c document that, since repeating it would be a no-op. | |
1836 | ||
1837 | @kindex show paths | |
1838 | @item show paths | |
1839 | Display the list of search paths for executables (the @code{PATH} | |
1840 | environment variable). | |
1841 | ||
1842 | @kindex show environment | |
1843 | @item show environment @r{[}@var{varname}@r{]} | |
1844 | Print the value of environment variable @var{varname} to be given to | |
1845 | your program when it starts. If you do not supply @var{varname}, | |
1846 | print the names and values of all environment variables to be given to | |
1847 | your program. You can abbreviate @code{environment} as @code{env}. | |
1848 | ||
1849 | @kindex set environment | |
53a5351d | 1850 | @item set environment @var{varname} @r{[}=@var{value}@r{]} |
c906108c SS |
1851 | Set environment variable @var{varname} to @var{value}. The value |
1852 | changes for your program only, not for @value{GDBN} itself. @var{value} may | |
1853 | be any string; the values of environment variables are just strings, and | |
1854 | any interpretation is supplied by your program itself. The @var{value} | |
1855 | parameter is optional; if it is eliminated, the variable is set to a | |
1856 | null value. | |
1857 | @c "any string" here does not include leading, trailing | |
1858 | @c blanks. Gnu asks: does anyone care? | |
1859 | ||
1860 | For example, this command: | |
1861 | ||
1862 | @example | |
1863 | set env USER = foo | |
1864 | @end example | |
1865 | ||
1866 | @noindent | |
d4f3574e | 1867 | tells the debugged program, when subsequently run, that its user is named |
c906108c SS |
1868 | @samp{foo}. (The spaces around @samp{=} are used for clarity here; they |
1869 | are not actually required.) | |
1870 | ||
1871 | @kindex unset environment | |
1872 | @item unset environment @var{varname} | |
1873 | Remove variable @var{varname} from the environment to be passed to your | |
1874 | program. This is different from @samp{set env @var{varname} =}; | |
1875 | @code{unset environment} removes the variable from the environment, | |
1876 | rather than assigning it an empty value. | |
1877 | @end table | |
1878 | ||
d4f3574e SS |
1879 | @emph{Warning:} On Unix systems, @value{GDBN} runs your program using |
1880 | the shell indicated | |
c906108c SS |
1881 | by your @code{SHELL} environment variable if it exists (or |
1882 | @code{/bin/sh} if not). If your @code{SHELL} variable names a shell | |
1883 | that runs an initialization file---such as @file{.cshrc} for C-shell, or | |
1884 | @file{.bashrc} for BASH---any variables you set in that file affect | |
1885 | your program. You may wish to move setting of environment variables to | |
1886 | files that are only run when you sign on, such as @file{.login} or | |
1887 | @file{.profile}. | |
1888 | ||
6d2ebf8b | 1889 | @node Working Directory |
c906108c SS |
1890 | @section Your program's working directory |
1891 | ||
1892 | @cindex working directory (of your program) | |
1893 | Each time you start your program with @code{run}, it inherits its | |
1894 | working directory from the current working directory of @value{GDBN}. | |
1895 | The @value{GDBN} working directory is initially whatever it inherited | |
1896 | from its parent process (typically the shell), but you can specify a new | |
1897 | working directory in @value{GDBN} with the @code{cd} command. | |
1898 | ||
1899 | The @value{GDBN} working directory also serves as a default for the commands | |
1900 | that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to | |
1901 | specify files}. | |
1902 | ||
1903 | @table @code | |
1904 | @kindex cd | |
1905 | @item cd @var{directory} | |
1906 | Set the @value{GDBN} working directory to @var{directory}. | |
1907 | ||
1908 | @kindex pwd | |
1909 | @item pwd | |
1910 | Print the @value{GDBN} working directory. | |
1911 | @end table | |
1912 | ||
6d2ebf8b | 1913 | @node Input/Output |
c906108c SS |
1914 | @section Your program's input and output |
1915 | ||
1916 | @cindex redirection | |
1917 | @cindex i/o | |
1918 | @cindex terminal | |
1919 | By default, the program you run under @value{GDBN} does input and output to | |
5d161b24 | 1920 | the same terminal that @value{GDBN} uses. @value{GDBN} switches the terminal |
c906108c SS |
1921 | to its own terminal modes to interact with you, but it records the terminal |
1922 | modes your program was using and switches back to them when you continue | |
1923 | running your program. | |
1924 | ||
1925 | @table @code | |
1926 | @kindex info terminal | |
1927 | @item info terminal | |
1928 | Displays information recorded by @value{GDBN} about the terminal modes your | |
1929 | program is using. | |
1930 | @end table | |
1931 | ||
1932 | You can redirect your program's input and/or output using shell | |
1933 | redirection with the @code{run} command. For example, | |
1934 | ||
1935 | @example | |
1936 | run > outfile | |
1937 | @end example | |
1938 | ||
1939 | @noindent | |
1940 | starts your program, diverting its output to the file @file{outfile}. | |
1941 | ||
1942 | @kindex tty | |
1943 | @cindex controlling terminal | |
1944 | Another way to specify where your program should do input and output is | |
1945 | with the @code{tty} command. This command accepts a file name as | |
1946 | argument, and causes this file to be the default for future @code{run} | |
1947 | commands. It also resets the controlling terminal for the child | |
1948 | process, for future @code{run} commands. For example, | |
1949 | ||
1950 | @example | |
1951 | tty /dev/ttyb | |
1952 | @end example | |
1953 | ||
1954 | @noindent | |
1955 | directs that processes started with subsequent @code{run} commands | |
1956 | default to do input and output on the terminal @file{/dev/ttyb} and have | |
1957 | that as their controlling terminal. | |
1958 | ||
1959 | An explicit redirection in @code{run} overrides the @code{tty} command's | |
1960 | effect on the input/output device, but not its effect on the controlling | |
1961 | terminal. | |
1962 | ||
1963 | When you use the @code{tty} command or redirect input in the @code{run} | |
1964 | command, only the input @emph{for your program} is affected. The input | |
1965 | for @value{GDBN} still comes from your terminal. | |
1966 | ||
6d2ebf8b | 1967 | @node Attach |
c906108c SS |
1968 | @section Debugging an already-running process |
1969 | @kindex attach | |
1970 | @cindex attach | |
1971 | ||
1972 | @table @code | |
1973 | @item attach @var{process-id} | |
1974 | This command attaches to a running process---one that was started | |
1975 | outside @value{GDBN}. (@code{info files} shows your active | |
1976 | targets.) The command takes as argument a process ID. The usual way to | |
1977 | find out the process-id of a Unix process is with the @code{ps} utility, | |
1978 | or with the @samp{jobs -l} shell command. | |
1979 | ||
1980 | @code{attach} does not repeat if you press @key{RET} a second time after | |
1981 | executing the command. | |
1982 | @end table | |
1983 | ||
1984 | To use @code{attach}, your program must be running in an environment | |
1985 | which supports processes; for example, @code{attach} does not work for | |
1986 | programs on bare-board targets that lack an operating system. You must | |
1987 | also have permission to send the process a signal. | |
1988 | ||
1989 | When you use @code{attach}, the debugger finds the program running in | |
1990 | the process first by looking in the current working directory, then (if | |
1991 | the program is not found) by using the source file search path | |
1992 | (@pxref{Source Path, ,Specifying source directories}). You can also use | |
1993 | the @code{file} command to load the program. @xref{Files, ,Commands to | |
1994 | Specify Files}. | |
1995 | ||
1996 | The first thing @value{GDBN} does after arranging to debug the specified | |
1997 | process is to stop it. You can examine and modify an attached process | |
53a5351d JM |
1998 | with all the @value{GDBN} commands that are ordinarily available when |
1999 | you start processes with @code{run}. You can insert breakpoints; you | |
2000 | can step and continue; you can modify storage. If you would rather the | |
2001 | process continue running, you may use the @code{continue} command after | |
c906108c SS |
2002 | attaching @value{GDBN} to the process. |
2003 | ||
2004 | @table @code | |
2005 | @kindex detach | |
2006 | @item detach | |
2007 | When you have finished debugging the attached process, you can use the | |
2008 | @code{detach} command to release it from @value{GDBN} control. Detaching | |
2009 | the process continues its execution. After the @code{detach} command, | |
2010 | that process and @value{GDBN} become completely independent once more, and you | |
2011 | are ready to @code{attach} another process or start one with @code{run}. | |
2012 | @code{detach} does not repeat if you press @key{RET} again after | |
2013 | executing the command. | |
2014 | @end table | |
2015 | ||
2016 | If you exit @value{GDBN} or use the @code{run} command while you have an | |
2017 | attached process, you kill that process. By default, @value{GDBN} asks | |
2018 | for confirmation if you try to do either of these things; you can | |
2019 | control whether or not you need to confirm by using the @code{set | |
2020 | confirm} command (@pxref{Messages/Warnings, ,Optional warnings and | |
2021 | messages}). | |
2022 | ||
6d2ebf8b | 2023 | @node Kill Process |
c906108c | 2024 | @section Killing the child process |
c906108c SS |
2025 | |
2026 | @table @code | |
2027 | @kindex kill | |
2028 | @item kill | |
2029 | Kill the child process in which your program is running under @value{GDBN}. | |
2030 | @end table | |
2031 | ||
2032 | This command is useful if you wish to debug a core dump instead of a | |
2033 | running process. @value{GDBN} ignores any core dump file while your program | |
2034 | is running. | |
2035 | ||
2036 | On some operating systems, a program cannot be executed outside @value{GDBN} | |
2037 | while you have breakpoints set on it inside @value{GDBN}. You can use the | |
2038 | @code{kill} command in this situation to permit running your program | |
2039 | outside the debugger. | |
2040 | ||
2041 | The @code{kill} command is also useful if you wish to recompile and | |
2042 | relink your program, since on many systems it is impossible to modify an | |
2043 | executable file while it is running in a process. In this case, when you | |
2044 | next type @code{run}, @value{GDBN} notices that the file has changed, and | |
2045 | reads the symbol table again (while trying to preserve your current | |
2046 | breakpoint settings). | |
2047 | ||
6d2ebf8b | 2048 | @node Threads |
c906108c | 2049 | @section Debugging programs with multiple threads |
c906108c SS |
2050 | |
2051 | @cindex threads of execution | |
2052 | @cindex multiple threads | |
2053 | @cindex switching threads | |
2054 | In some operating systems, such as HP-UX and Solaris, a single program | |
2055 | may have more than one @dfn{thread} of execution. The precise semantics | |
2056 | of threads differ from one operating system to another, but in general | |
2057 | the threads of a single program are akin to multiple processes---except | |
2058 | that they share one address space (that is, they can all examine and | |
2059 | modify the same variables). On the other hand, each thread has its own | |
2060 | registers and execution stack, and perhaps private memory. | |
2061 | ||
2062 | @value{GDBN} provides these facilities for debugging multi-thread | |
2063 | programs: | |
2064 | ||
2065 | @itemize @bullet | |
2066 | @item automatic notification of new threads | |
2067 | @item @samp{thread @var{threadno}}, a command to switch among threads | |
2068 | @item @samp{info threads}, a command to inquire about existing threads | |
5d161b24 | 2069 | @item @samp{thread apply [@var{threadno}] [@var{all}] @var{args}}, |
c906108c SS |
2070 | a command to apply a command to a list of threads |
2071 | @item thread-specific breakpoints | |
2072 | @end itemize | |
2073 | ||
c906108c SS |
2074 | @quotation |
2075 | @emph{Warning:} These facilities are not yet available on every | |
2076 | @value{GDBN} configuration where the operating system supports threads. | |
2077 | If your @value{GDBN} does not support threads, these commands have no | |
2078 | effect. For example, a system without thread support shows no output | |
2079 | from @samp{info threads}, and always rejects the @code{thread} command, | |
2080 | like this: | |
2081 | ||
2082 | @smallexample | |
2083 | (@value{GDBP}) info threads | |
2084 | (@value{GDBP}) thread 1 | |
2085 | Thread ID 1 not known. Use the "info threads" command to | |
2086 | see the IDs of currently known threads. | |
2087 | @end smallexample | |
2088 | @c FIXME to implementors: how hard would it be to say "sorry, this GDB | |
2089 | @c doesn't support threads"? | |
2090 | @end quotation | |
c906108c SS |
2091 | |
2092 | @cindex focus of debugging | |
2093 | @cindex current thread | |
2094 | The @value{GDBN} thread debugging facility allows you to observe all | |
2095 | threads while your program runs---but whenever @value{GDBN} takes | |
2096 | control, one thread in particular is always the focus of debugging. | |
2097 | This thread is called the @dfn{current thread}. Debugging commands show | |
2098 | program information from the perspective of the current thread. | |
2099 | ||
41afff9a | 2100 | @cindex @code{New} @var{systag} message |
c906108c SS |
2101 | @cindex thread identifier (system) |
2102 | @c FIXME-implementors!! It would be more helpful if the [New...] message | |
2103 | @c included GDB's numeric thread handle, so you could just go to that | |
2104 | @c thread without first checking `info threads'. | |
2105 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2106 | the target system's identification for the thread with a message in the | |
2107 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2108 | whose form varies depending on the particular system. For example, on | |
2109 | LynxOS, you might see | |
2110 | ||
2111 | @example | |
2112 | [New process 35 thread 27] | |
2113 | @end example | |
2114 | ||
2115 | @noindent | |
2116 | when @value{GDBN} notices a new thread. In contrast, on an SGI system, | |
2117 | the @var{systag} is simply something like @samp{process 368}, with no | |
2118 | further qualifier. | |
2119 | ||
2120 | @c FIXME!! (1) Does the [New...] message appear even for the very first | |
2121 | @c thread of a program, or does it only appear for the | |
2122 | @c second---i.e., when it becomes obvious we have a multithread | |
2123 | @c program? | |
2124 | @c (2) *Is* there necessarily a first thread always? Or do some | |
2125 | @c multithread systems permit starting a program with multiple | |
5d161b24 | 2126 | @c threads ab initio? |
c906108c SS |
2127 | |
2128 | @cindex thread number | |
2129 | @cindex thread identifier (GDB) | |
2130 | For debugging purposes, @value{GDBN} associates its own thread | |
2131 | number---always a single integer---with each thread in your program. | |
2132 | ||
2133 | @table @code | |
2134 | @kindex info threads | |
2135 | @item info threads | |
2136 | Display a summary of all threads currently in your | |
2137 | program. @value{GDBN} displays for each thread (in this order): | |
2138 | ||
2139 | @enumerate | |
2140 | @item the thread number assigned by @value{GDBN} | |
2141 | ||
2142 | @item the target system's thread identifier (@var{systag}) | |
2143 | ||
2144 | @item the current stack frame summary for that thread | |
2145 | @end enumerate | |
2146 | ||
2147 | @noindent | |
2148 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2149 | indicates the current thread. | |
2150 | ||
5d161b24 | 2151 | For example, |
c906108c SS |
2152 | @end table |
2153 | @c end table here to get a little more width for example | |
2154 | ||
2155 | @smallexample | |
2156 | (@value{GDBP}) info threads | |
2157 | 3 process 35 thread 27 0x34e5 in sigpause () | |
2158 | 2 process 35 thread 23 0x34e5 in sigpause () | |
2159 | * 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8) | |
2160 | at threadtest.c:68 | |
2161 | @end smallexample | |
53a5351d JM |
2162 | |
2163 | On HP-UX systems: | |
c906108c SS |
2164 | |
2165 | @cindex thread number | |
2166 | @cindex thread identifier (GDB) | |
2167 | For debugging purposes, @value{GDBN} associates its own thread | |
2168 | number---a small integer assigned in thread-creation order---with each | |
2169 | thread in your program. | |
2170 | ||
41afff9a EZ |
2171 | @cindex @code{New} @var{systag} message, on HP-UX |
2172 | @cindex thread identifier (system), on HP-UX | |
c906108c SS |
2173 | @c FIXME-implementors!! It would be more helpful if the [New...] message |
2174 | @c included GDB's numeric thread handle, so you could just go to that | |
2175 | @c thread without first checking `info threads'. | |
2176 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2177 | both @value{GDBN}'s thread number and the target system's identification for the thread with a message in the | |
2178 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2179 | whose form varies depending on the particular system. For example, on | |
2180 | HP-UX, you see | |
2181 | ||
2182 | @example | |
2183 | [New thread 2 (system thread 26594)] | |
2184 | @end example | |
2185 | ||
2186 | @noindent | |
5d161b24 | 2187 | when @value{GDBN} notices a new thread. |
c906108c SS |
2188 | |
2189 | @table @code | |
2190 | @kindex info threads | |
2191 | @item info threads | |
2192 | Display a summary of all threads currently in your | |
2193 | program. @value{GDBN} displays for each thread (in this order): | |
2194 | ||
2195 | @enumerate | |
2196 | @item the thread number assigned by @value{GDBN} | |
2197 | ||
2198 | @item the target system's thread identifier (@var{systag}) | |
2199 | ||
2200 | @item the current stack frame summary for that thread | |
2201 | @end enumerate | |
2202 | ||
2203 | @noindent | |
2204 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2205 | indicates the current thread. | |
2206 | ||
5d161b24 | 2207 | For example, |
c906108c SS |
2208 | @end table |
2209 | @c end table here to get a little more width for example | |
2210 | ||
2211 | @example | |
2212 | (@value{GDBP}) info threads | |
6d2ebf8b SS |
2213 | * 3 system thread 26607 worker (wptr=0x7b09c318 "@@") \@* |
2214 | at quicksort.c:137 | |
2215 | 2 system thread 26606 0x7b0030d8 in __ksleep () \@* | |
2216 | from /usr/lib/libc.2 | |
2217 | 1 system thread 27905 0x7b003498 in _brk () \@* | |
2218 | from /usr/lib/libc.2 | |
c906108c | 2219 | @end example |
c906108c SS |
2220 | |
2221 | @table @code | |
2222 | @kindex thread @var{threadno} | |
2223 | @item thread @var{threadno} | |
2224 | Make thread number @var{threadno} the current thread. The command | |
2225 | argument @var{threadno} is the internal @value{GDBN} thread number, as | |
2226 | shown in the first field of the @samp{info threads} display. | |
2227 | @value{GDBN} responds by displaying the system identifier of the thread | |
2228 | you selected, and its current stack frame summary: | |
2229 | ||
2230 | @smallexample | |
2231 | @c FIXME!! This example made up; find a @value{GDBN} w/threads and get real one | |
2232 | (@value{GDBP}) thread 2 | |
c906108c | 2233 | [Switching to process 35 thread 23] |
c906108c SS |
2234 | 0x34e5 in sigpause () |
2235 | @end smallexample | |
2236 | ||
2237 | @noindent | |
2238 | As with the @samp{[New @dots{}]} message, the form of the text after | |
2239 | @samp{Switching to} depends on your system's conventions for identifying | |
5d161b24 | 2240 | threads. |
c906108c SS |
2241 | |
2242 | @kindex thread apply | |
2243 | @item thread apply [@var{threadno}] [@var{all}] @var{args} | |
2244 | The @code{thread apply} command allows you to apply a command to one or | |
2245 | more threads. Specify the numbers of the threads that you want affected | |
2246 | with the command argument @var{threadno}. @var{threadno} is the internal | |
2247 | @value{GDBN} thread number, as shown in the first field of the @samp{info | |
5d161b24 DB |
2248 | threads} display. To apply a command to all threads, use |
2249 | @code{thread apply all} @var{args}. | |
c906108c SS |
2250 | @end table |
2251 | ||
2252 | @cindex automatic thread selection | |
2253 | @cindex switching threads automatically | |
2254 | @cindex threads, automatic switching | |
2255 | Whenever @value{GDBN} stops your program, due to a breakpoint or a | |
2256 | signal, it automatically selects the thread where that breakpoint or | |
2257 | signal happened. @value{GDBN} alerts you to the context switch with a | |
2258 | message of the form @samp{[Switching to @var{systag}]} to identify the | |
2259 | thread. | |
2260 | ||
2261 | @xref{Thread Stops,,Stopping and starting multi-thread programs}, for | |
2262 | more information about how @value{GDBN} behaves when you stop and start | |
2263 | programs with multiple threads. | |
2264 | ||
2265 | @xref{Set Watchpoints,,Setting watchpoints}, for information about | |
2266 | watchpoints in programs with multiple threads. | |
c906108c | 2267 | |
6d2ebf8b | 2268 | @node Processes |
c906108c SS |
2269 | @section Debugging programs with multiple processes |
2270 | ||
2271 | @cindex fork, debugging programs which call | |
2272 | @cindex multiple processes | |
2273 | @cindex processes, multiple | |
53a5351d JM |
2274 | On most systems, @value{GDBN} has no special support for debugging |
2275 | programs which create additional processes using the @code{fork} | |
2276 | function. When a program forks, @value{GDBN} will continue to debug the | |
2277 | parent process and the child process will run unimpeded. If you have | |
2278 | set a breakpoint in any code which the child then executes, the child | |
2279 | will get a @code{SIGTRAP} signal which (unless it catches the signal) | |
2280 | will cause it to terminate. | |
c906108c SS |
2281 | |
2282 | However, if you want to debug the child process there is a workaround | |
2283 | which isn't too painful. Put a call to @code{sleep} in the code which | |
2284 | the child process executes after the fork. It may be useful to sleep | |
2285 | only if a certain environment variable is set, or a certain file exists, | |
2286 | so that the delay need not occur when you don't want to run @value{GDBN} | |
2287 | on the child. While the child is sleeping, use the @code{ps} program to | |
2288 | get its process ID. Then tell @value{GDBN} (a new invocation of | |
2289 | @value{GDBN} if you are also debugging the parent process) to attach to | |
d4f3574e | 2290 | the child process (@pxref{Attach}). From that point on you can debug |
c906108c | 2291 | the child process just like any other process which you attached to. |
c906108c | 2292 | |
53a5351d JM |
2293 | On HP-UX (11.x and later only?), @value{GDBN} provides support for |
2294 | debugging programs that create additional processes using the | |
2295 | @code{fork} or @code{vfork} function. | |
c906108c SS |
2296 | |
2297 | By default, when a program forks, @value{GDBN} will continue to debug | |
2298 | the parent process and the child process will run unimpeded. | |
2299 | ||
2300 | If you want to follow the child process instead of the parent process, | |
2301 | use the command @w{@code{set follow-fork-mode}}. | |
2302 | ||
2303 | @table @code | |
2304 | @kindex set follow-fork-mode | |
2305 | @item set follow-fork-mode @var{mode} | |
2306 | Set the debugger response to a program call of @code{fork} or | |
2307 | @code{vfork}. A call to @code{fork} or @code{vfork} creates a new | |
2308 | process. The @var{mode} can be: | |
2309 | ||
2310 | @table @code | |
2311 | @item parent | |
2312 | The original process is debugged after a fork. The child process runs | |
2df3850c | 2313 | unimpeded. This is the default. |
c906108c SS |
2314 | |
2315 | @item child | |
2316 | The new process is debugged after a fork. The parent process runs | |
2317 | unimpeded. | |
2318 | ||
2319 | @item ask | |
2320 | The debugger will ask for one of the above choices. | |
2321 | @end table | |
2322 | ||
2323 | @item show follow-fork-mode | |
2df3850c | 2324 | Display the current debugger response to a @code{fork} or @code{vfork} call. |
c906108c SS |
2325 | @end table |
2326 | ||
2327 | If you ask to debug a child process and a @code{vfork} is followed by an | |
2328 | @code{exec}, @value{GDBN} executes the new target up to the first | |
2329 | breakpoint in the new target. If you have a breakpoint set on | |
2330 | @code{main} in your original program, the breakpoint will also be set on | |
2331 | the child process's @code{main}. | |
2332 | ||
2333 | When a child process is spawned by @code{vfork}, you cannot debug the | |
2334 | child or parent until an @code{exec} call completes. | |
2335 | ||
2336 | If you issue a @code{run} command to @value{GDBN} after an @code{exec} | |
2337 | call executes, the new target restarts. To restart the parent process, | |
2338 | use the @code{file} command with the parent executable name as its | |
2339 | argument. | |
2340 | ||
2341 | You can use the @code{catch} command to make @value{GDBN} stop whenever | |
2342 | a @code{fork}, @code{vfork}, or @code{exec} call is made. @xref{Set | |
2343 | Catchpoints, ,Setting catchpoints}. | |
c906108c | 2344 | |
6d2ebf8b | 2345 | @node Stopping |
c906108c SS |
2346 | @chapter Stopping and Continuing |
2347 | ||
2348 | The principal purposes of using a debugger are so that you can stop your | |
2349 | program before it terminates; or so that, if your program runs into | |
2350 | trouble, you can investigate and find out why. | |
2351 | ||
7a292a7a SS |
2352 | Inside @value{GDBN}, your program may stop for any of several reasons, |
2353 | such as a signal, a breakpoint, or reaching a new line after a | |
2354 | @value{GDBN} command such as @code{step}. You may then examine and | |
2355 | change variables, set new breakpoints or remove old ones, and then | |
2356 | continue execution. Usually, the messages shown by @value{GDBN} provide | |
2357 | ample explanation of the status of your program---but you can also | |
2358 | explicitly request this information at any time. | |
c906108c SS |
2359 | |
2360 | @table @code | |
2361 | @kindex info program | |
2362 | @item info program | |
2363 | Display information about the status of your program: whether it is | |
7a292a7a | 2364 | running or not, what process it is, and why it stopped. |
c906108c SS |
2365 | @end table |
2366 | ||
2367 | @menu | |
2368 | * Breakpoints:: Breakpoints, watchpoints, and catchpoints | |
2369 | * Continuing and Stepping:: Resuming execution | |
c906108c | 2370 | * Signals:: Signals |
c906108c | 2371 | * Thread Stops:: Stopping and starting multi-thread programs |
c906108c SS |
2372 | @end menu |
2373 | ||
6d2ebf8b | 2374 | @node Breakpoints |
c906108c SS |
2375 | @section Breakpoints, watchpoints, and catchpoints |
2376 | ||
2377 | @cindex breakpoints | |
2378 | A @dfn{breakpoint} makes your program stop whenever a certain point in | |
2379 | the program is reached. For each breakpoint, you can add conditions to | |
2380 | control in finer detail whether your program stops. You can set | |
2381 | breakpoints with the @code{break} command and its variants (@pxref{Set | |
2382 | Breaks, ,Setting breakpoints}), to specify the place where your program | |
2383 | should stop by line number, function name or exact address in the | |
2384 | program. | |
2385 | ||
2386 | In HP-UX, SunOS 4.x, SVR4, and Alpha OSF/1 configurations, you can set | |
2387 | breakpoints in shared libraries before the executable is run. There is | |
2388 | a minor limitation on HP-UX systems: you must wait until the executable | |
2389 | is run in order to set breakpoints in shared library routines that are | |
2390 | not called directly by the program (for example, routines that are | |
2391 | arguments in a @code{pthread_create} call). | |
2392 | ||
2393 | @cindex watchpoints | |
2394 | @cindex memory tracing | |
2395 | @cindex breakpoint on memory address | |
2396 | @cindex breakpoint on variable modification | |
2397 | A @dfn{watchpoint} is a special breakpoint that stops your program | |
2398 | when the value of an expression changes. You must use a different | |
2399 | command to set watchpoints (@pxref{Set Watchpoints, ,Setting | |
2400 | watchpoints}), but aside from that, you can manage a watchpoint like | |
2401 | any other breakpoint: you enable, disable, and delete both breakpoints | |
2402 | and watchpoints using the same commands. | |
2403 | ||
2404 | You can arrange to have values from your program displayed automatically | |
2405 | whenever @value{GDBN} stops at a breakpoint. @xref{Auto Display,, | |
2406 | Automatic display}. | |
2407 | ||
2408 | @cindex catchpoints | |
2409 | @cindex breakpoint on events | |
2410 | A @dfn{catchpoint} is another special breakpoint that stops your program | |
b37052ae | 2411 | when a certain kind of event occurs, such as the throwing of a C@t{++} |
c906108c SS |
2412 | exception or the loading of a library. As with watchpoints, you use a |
2413 | different command to set a catchpoint (@pxref{Set Catchpoints, ,Setting | |
2414 | catchpoints}), but aside from that, you can manage a catchpoint like any | |
2415 | other breakpoint. (To stop when your program receives a signal, use the | |
d4f3574e | 2416 | @code{handle} command; see @ref{Signals, ,Signals}.) |
c906108c SS |
2417 | |
2418 | @cindex breakpoint numbers | |
2419 | @cindex numbers for breakpoints | |
2420 | @value{GDBN} assigns a number to each breakpoint, watchpoint, or | |
2421 | catchpoint when you create it; these numbers are successive integers | |
2422 | starting with one. In many of the commands for controlling various | |
2423 | features of breakpoints you use the breakpoint number to say which | |
2424 | breakpoint you want to change. Each breakpoint may be @dfn{enabled} or | |
2425 | @dfn{disabled}; if disabled, it has no effect on your program until you | |
2426 | enable it again. | |
2427 | ||
c5394b80 JM |
2428 | @cindex breakpoint ranges |
2429 | @cindex ranges of breakpoints | |
2430 | Some @value{GDBN} commands accept a range of breakpoints on which to | |
2431 | operate. A breakpoint range is either a single breakpoint number, like | |
2432 | @samp{5}, or two such numbers, in increasing order, separated by a | |
2433 | hyphen, like @samp{5-7}. When a breakpoint range is given to a command, | |
2434 | all breakpoint in that range are operated on. | |
2435 | ||
c906108c SS |
2436 | @menu |
2437 | * Set Breaks:: Setting breakpoints | |
2438 | * Set Watchpoints:: Setting watchpoints | |
2439 | * Set Catchpoints:: Setting catchpoints | |
2440 | * Delete Breaks:: Deleting breakpoints | |
2441 | * Disabling:: Disabling breakpoints | |
2442 | * Conditions:: Break conditions | |
2443 | * Break Commands:: Breakpoint command lists | |
c906108c | 2444 | * Breakpoint Menus:: Breakpoint menus |
d4f3574e | 2445 | * Error in Breakpoints:: ``Cannot insert breakpoints'' |
c906108c SS |
2446 | @end menu |
2447 | ||
6d2ebf8b | 2448 | @node Set Breaks |
c906108c SS |
2449 | @subsection Setting breakpoints |
2450 | ||
5d161b24 | 2451 | @c FIXME LMB what does GDB do if no code on line of breakpt? |
c906108c SS |
2452 | @c consider in particular declaration with/without initialization. |
2453 | @c | |
2454 | @c FIXME 2 is there stuff on this already? break at fun start, already init? | |
2455 | ||
2456 | @kindex break | |
41afff9a EZ |
2457 | @kindex b @r{(@code{break})} |
2458 | @vindex $bpnum@r{, convenience variable} | |
c906108c SS |
2459 | @cindex latest breakpoint |
2460 | Breakpoints are set with the @code{break} command (abbreviated | |
5d161b24 | 2461 | @code{b}). The debugger convenience variable @samp{$bpnum} records the |
f3b28801 | 2462 | number of the breakpoint you've set most recently; see @ref{Convenience |
c906108c SS |
2463 | Vars,, Convenience variables}, for a discussion of what you can do with |
2464 | convenience variables. | |
2465 | ||
2466 | You have several ways to say where the breakpoint should go. | |
2467 | ||
2468 | @table @code | |
2469 | @item break @var{function} | |
5d161b24 | 2470 | Set a breakpoint at entry to function @var{function}. |
c906108c | 2471 | When using source languages that permit overloading of symbols, such as |
b37052ae | 2472 | C@t{++}, @var{function} may refer to more than one possible place to break. |
c906108c | 2473 | @xref{Breakpoint Menus,,Breakpoint menus}, for a discussion of that situation. |
c906108c SS |
2474 | |
2475 | @item break +@var{offset} | |
2476 | @itemx break -@var{offset} | |
2477 | Set a breakpoint some number of lines forward or back from the position | |
d4f3574e | 2478 | at which execution stopped in the currently selected @dfn{stack frame}. |
2df3850c | 2479 | (@xref{Frames, ,Frames}, for a description of stack frames.) |
c906108c SS |
2480 | |
2481 | @item break @var{linenum} | |
2482 | Set a breakpoint at line @var{linenum} in the current source file. | |
d4f3574e SS |
2483 | The current source file is the last file whose source text was printed. |
2484 | The breakpoint will stop your program just before it executes any of the | |
c906108c SS |
2485 | code on that line. |
2486 | ||
2487 | @item break @var{filename}:@var{linenum} | |
2488 | Set a breakpoint at line @var{linenum} in source file @var{filename}. | |
2489 | ||
2490 | @item break @var{filename}:@var{function} | |
2491 | Set a breakpoint at entry to function @var{function} found in file | |
2492 | @var{filename}. Specifying a file name as well as a function name is | |
2493 | superfluous except when multiple files contain similarly named | |
2494 | functions. | |
2495 | ||
2496 | @item break *@var{address} | |
2497 | Set a breakpoint at address @var{address}. You can use this to set | |
2498 | breakpoints in parts of your program which do not have debugging | |
2499 | information or source files. | |
2500 | ||
2501 | @item break | |
2502 | When called without any arguments, @code{break} sets a breakpoint at | |
2503 | the next instruction to be executed in the selected stack frame | |
2504 | (@pxref{Stack, ,Examining the Stack}). In any selected frame but the | |
2505 | innermost, this makes your program stop as soon as control | |
2506 | returns to that frame. This is similar to the effect of a | |
2507 | @code{finish} command in the frame inside the selected frame---except | |
2508 | that @code{finish} does not leave an active breakpoint. If you use | |
2509 | @code{break} without an argument in the innermost frame, @value{GDBN} stops | |
2510 | the next time it reaches the current location; this may be useful | |
2511 | inside loops. | |
2512 | ||
2513 | @value{GDBN} normally ignores breakpoints when it resumes execution, until at | |
2514 | least one instruction has been executed. If it did not do this, you | |
2515 | would be unable to proceed past a breakpoint without first disabling the | |
2516 | breakpoint. This rule applies whether or not the breakpoint already | |
2517 | existed when your program stopped. | |
2518 | ||
2519 | @item break @dots{} if @var{cond} | |
2520 | Set a breakpoint with condition @var{cond}; evaluate the expression | |
2521 | @var{cond} each time the breakpoint is reached, and stop only if the | |
2522 | value is nonzero---that is, if @var{cond} evaluates as true. | |
2523 | @samp{@dots{}} stands for one of the possible arguments described | |
2524 | above (or no argument) specifying where to break. @xref{Conditions, | |
2525 | ,Break conditions}, for more information on breakpoint conditions. | |
2526 | ||
2527 | @kindex tbreak | |
2528 | @item tbreak @var{args} | |
2529 | Set a breakpoint enabled only for one stop. @var{args} are the | |
2530 | same as for the @code{break} command, and the breakpoint is set in the same | |
2531 | way, but the breakpoint is automatically deleted after the first time your | |
2532 | program stops there. @xref{Disabling, ,Disabling breakpoints}. | |
2533 | ||
c906108c SS |
2534 | @kindex hbreak |
2535 | @item hbreak @var{args} | |
d4f3574e SS |
2536 | Set a hardware-assisted breakpoint. @var{args} are the same as for the |
2537 | @code{break} command and the breakpoint is set in the same way, but the | |
c906108c SS |
2538 | breakpoint requires hardware support and some target hardware may not |
2539 | have this support. The main purpose of this is EPROM/ROM code | |
d4f3574e SS |
2540 | debugging, so you can set a breakpoint at an instruction without |
2541 | changing the instruction. This can be used with the new trap-generation | |
2542 | provided by SPARClite DSU and some x86-based targets. These targets | |
2543 | will generate traps when a program accesses some data or instruction | |
2544 | address that is assigned to the debug registers. However the hardware | |
2545 | breakpoint registers can take a limited number of breakpoints. For | |
2546 | example, on the DSU, only two data breakpoints can be set at a time, and | |
2547 | @value{GDBN} will reject this command if more than two are used. Delete | |
2548 | or disable unused hardware breakpoints before setting new ones | |
2549 | (@pxref{Disabling, ,Disabling}). @xref{Conditions, ,Break conditions}. | |
c906108c SS |
2550 | |
2551 | @kindex thbreak | |
2552 | @item thbreak @var{args} | |
2553 | Set a hardware-assisted breakpoint enabled only for one stop. @var{args} | |
2554 | are the same as for the @code{hbreak} command and the breakpoint is set in | |
5d161b24 | 2555 | the same way. However, like the @code{tbreak} command, |
c906108c SS |
2556 | the breakpoint is automatically deleted after the |
2557 | first time your program stops there. Also, like the @code{hbreak} | |
5d161b24 DB |
2558 | command, the breakpoint requires hardware support and some target hardware |
2559 | may not have this support. @xref{Disabling, ,Disabling breakpoints}. | |
d4f3574e | 2560 | See also @ref{Conditions, ,Break conditions}. |
c906108c SS |
2561 | |
2562 | @kindex rbreak | |
2563 | @cindex regular expression | |
2564 | @item rbreak @var{regex} | |
c906108c | 2565 | Set breakpoints on all functions matching the regular expression |
11cf8741 JM |
2566 | @var{regex}. This command sets an unconditional breakpoint on all |
2567 | matches, printing a list of all breakpoints it set. Once these | |
2568 | breakpoints are set, they are treated just like the breakpoints set with | |
2569 | the @code{break} command. You can delete them, disable them, or make | |
2570 | them conditional the same way as any other breakpoint. | |
2571 | ||
2572 | The syntax of the regular expression is the standard one used with tools | |
2573 | like @file{grep}. Note that this is different from the syntax used by | |
2574 | shells, so for instance @code{foo*} matches all functions that include | |
2575 | an @code{fo} followed by zero or more @code{o}s. There is an implicit | |
2576 | @code{.*} leading and trailing the regular expression you supply, so to | |
2577 | match only functions that begin with @code{foo}, use @code{^foo}. | |
c906108c | 2578 | |
b37052ae | 2579 | When debugging C@t{++} programs, @code{rbreak} is useful for setting |
c906108c SS |
2580 | breakpoints on overloaded functions that are not members of any special |
2581 | classes. | |
c906108c SS |
2582 | |
2583 | @kindex info breakpoints | |
2584 | @cindex @code{$_} and @code{info breakpoints} | |
2585 | @item info breakpoints @r{[}@var{n}@r{]} | |
2586 | @itemx info break @r{[}@var{n}@r{]} | |
2587 | @itemx info watchpoints @r{[}@var{n}@r{]} | |
2588 | Print a table of all breakpoints, watchpoints, and catchpoints set and | |
2589 | not deleted, with the following columns for each breakpoint: | |
2590 | ||
2591 | @table @emph | |
2592 | @item Breakpoint Numbers | |
2593 | @item Type | |
2594 | Breakpoint, watchpoint, or catchpoint. | |
2595 | @item Disposition | |
2596 | Whether the breakpoint is marked to be disabled or deleted when hit. | |
2597 | @item Enabled or Disabled | |
2598 | Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints | |
2599 | that are not enabled. | |
2600 | @item Address | |
2df3850c | 2601 | Where the breakpoint is in your program, as a memory address. |
c906108c SS |
2602 | @item What |
2603 | Where the breakpoint is in the source for your program, as a file and | |
2604 | line number. | |
2605 | @end table | |
2606 | ||
2607 | @noindent | |
2608 | If a breakpoint is conditional, @code{info break} shows the condition on | |
2609 | the line following the affected breakpoint; breakpoint commands, if any, | |
2610 | are listed after that. | |
2611 | ||
2612 | @noindent | |
2613 | @code{info break} with a breakpoint | |
2614 | number @var{n} as argument lists only that breakpoint. The | |
2615 | convenience variable @code{$_} and the default examining-address for | |
2616 | the @code{x} command are set to the address of the last breakpoint | |
5d161b24 | 2617 | listed (@pxref{Memory, ,Examining memory}). |
c906108c SS |
2618 | |
2619 | @noindent | |
2620 | @code{info break} displays a count of the number of times the breakpoint | |
2621 | has been hit. This is especially useful in conjunction with the | |
2622 | @code{ignore} command. You can ignore a large number of breakpoint | |
2623 | hits, look at the breakpoint info to see how many times the breakpoint | |
2624 | was hit, and then run again, ignoring one less than that number. This | |
2625 | will get you quickly to the last hit of that breakpoint. | |
2626 | @end table | |
2627 | ||
2628 | @value{GDBN} allows you to set any number of breakpoints at the same place in | |
2629 | your program. There is nothing silly or meaningless about this. When | |
2630 | the breakpoints are conditional, this is even useful | |
2631 | (@pxref{Conditions, ,Break conditions}). | |
2632 | ||
2633 | @cindex negative breakpoint numbers | |
2634 | @cindex internal @value{GDBN} breakpoints | |
eb12ee30 AC |
2635 | @value{GDBN} itself sometimes sets breakpoints in your program for |
2636 | special purposes, such as proper handling of @code{longjmp} (in C | |
2637 | programs). These internal breakpoints are assigned negative numbers, | |
2638 | starting with @code{-1}; @samp{info breakpoints} does not display them. | |
c906108c | 2639 | You can see these breakpoints with the @value{GDBN} maintenance command |
eb12ee30 | 2640 | @samp{maint info breakpoints} (@pxref{maint info breakpoints}). |
c906108c SS |
2641 | |
2642 | ||
6d2ebf8b | 2643 | @node Set Watchpoints |
c906108c SS |
2644 | @subsection Setting watchpoints |
2645 | ||
2646 | @cindex setting watchpoints | |
2647 | @cindex software watchpoints | |
2648 | @cindex hardware watchpoints | |
2649 | You can use a watchpoint to stop execution whenever the value of an | |
2650 | expression changes, without having to predict a particular place where | |
2651 | this may happen. | |
2652 | ||
2653 | Depending on your system, watchpoints may be implemented in software or | |
2df3850c | 2654 | hardware. @value{GDBN} does software watchpointing by single-stepping your |
c906108c SS |
2655 | program and testing the variable's value each time, which is hundreds of |
2656 | times slower than normal execution. (But this may still be worth it, to | |
2657 | catch errors where you have no clue what part of your program is the | |
2658 | culprit.) | |
2659 | ||
d4f3574e | 2660 | On some systems, such as HP-UX, Linux and some other x86-based targets, |
2df3850c | 2661 | @value{GDBN} includes support for |
c906108c SS |
2662 | hardware watchpoints, which do not slow down the running of your |
2663 | program. | |
2664 | ||
2665 | @table @code | |
2666 | @kindex watch | |
2667 | @item watch @var{expr} | |
2668 | Set a watchpoint for an expression. @value{GDBN} will break when @var{expr} | |
2669 | is written into by the program and its value changes. | |
2670 | ||
2671 | @kindex rwatch | |
2672 | @item rwatch @var{expr} | |
2673 | Set a watchpoint that will break when watch @var{expr} is read by the program. | |
c906108c SS |
2674 | |
2675 | @kindex awatch | |
2676 | @item awatch @var{expr} | |
2df3850c | 2677 | Set a watchpoint that will break when @var{expr} is either read or written into |
7be570e7 | 2678 | by the program. |
c906108c SS |
2679 | |
2680 | @kindex info watchpoints | |
2681 | @item info watchpoints | |
2682 | This command prints a list of watchpoints, breakpoints, and catchpoints; | |
2683 | it is the same as @code{info break}. | |
2684 | @end table | |
2685 | ||
2686 | @value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware | |
2687 | watchpoints execute very quickly, and the debugger reports a change in | |
2688 | value at the exact instruction where the change occurs. If @value{GDBN} | |
2689 | cannot set a hardware watchpoint, it sets a software watchpoint, which | |
2690 | executes more slowly and reports the change in value at the next | |
2691 | statement, not the instruction, after the change occurs. | |
2692 | ||
2693 | When you issue the @code{watch} command, @value{GDBN} reports | |
2694 | ||
2695 | @example | |
2696 | Hardware watchpoint @var{num}: @var{expr} | |
2697 | @end example | |
2698 | ||
2699 | @noindent | |
2700 | if it was able to set a hardware watchpoint. | |
2701 | ||
7be570e7 JM |
2702 | Currently, the @code{awatch} and @code{rwatch} commands can only set |
2703 | hardware watchpoints, because accesses to data that don't change the | |
2704 | value of the watched expression cannot be detected without examining | |
2705 | every instruction as it is being executed, and @value{GDBN} does not do | |
2706 | that currently. If @value{GDBN} finds that it is unable to set a | |
2707 | hardware breakpoint with the @code{awatch} or @code{rwatch} command, it | |
2708 | will print a message like this: | |
2709 | ||
2710 | @smallexample | |
2711 | Expression cannot be implemented with read/access watchpoint. | |
2712 | @end smallexample | |
2713 | ||
2714 | Sometimes, @value{GDBN} cannot set a hardware watchpoint because the | |
2715 | data type of the watched expression is wider than what a hardware | |
2716 | watchpoint on the target machine can handle. For example, some systems | |
2717 | can only watch regions that are up to 4 bytes wide; on such systems you | |
2718 | cannot set hardware watchpoints for an expression that yields a | |
2719 | double-precision floating-point number (which is typically 8 bytes | |
2720 | wide). As a work-around, it might be possible to break the large region | |
2721 | into a series of smaller ones and watch them with separate watchpoints. | |
2722 | ||
2723 | If you set too many hardware watchpoints, @value{GDBN} might be unable | |
2724 | to insert all of them when you resume the execution of your program. | |
2725 | Since the precise number of active watchpoints is unknown until such | |
2726 | time as the program is about to be resumed, @value{GDBN} might not be | |
2727 | able to warn you about this when you set the watchpoints, and the | |
2728 | warning will be printed only when the program is resumed: | |
2729 | ||
2730 | @smallexample | |
2731 | Hardware watchpoint @var{num}: Could not insert watchpoint | |
2732 | @end smallexample | |
2733 | ||
2734 | @noindent | |
2735 | If this happens, delete or disable some of the watchpoints. | |
2736 | ||
2737 | The SPARClite DSU will generate traps when a program accesses some data | |
2738 | or instruction address that is assigned to the debug registers. For the | |
2739 | data addresses, DSU facilitates the @code{watch} command. However the | |
2740 | hardware breakpoint registers can only take two data watchpoints, and | |
2741 | both watchpoints must be the same kind. For example, you can set two | |
2742 | watchpoints with @code{watch} commands, two with @code{rwatch} commands, | |
2743 | @strong{or} two with @code{awatch} commands, but you cannot set one | |
2744 | watchpoint with one command and the other with a different command. | |
c906108c SS |
2745 | @value{GDBN} will reject the command if you try to mix watchpoints. |
2746 | Delete or disable unused watchpoint commands before setting new ones. | |
2747 | ||
2748 | If you call a function interactively using @code{print} or @code{call}, | |
2df3850c | 2749 | any watchpoints you have set will be inactive until @value{GDBN} reaches another |
c906108c SS |
2750 | kind of breakpoint or the call completes. |
2751 | ||
7be570e7 JM |
2752 | @value{GDBN} automatically deletes watchpoints that watch local |
2753 | (automatic) variables, or expressions that involve such variables, when | |
2754 | they go out of scope, that is, when the execution leaves the block in | |
2755 | which these variables were defined. In particular, when the program | |
2756 | being debugged terminates, @emph{all} local variables go out of scope, | |
2757 | and so only watchpoints that watch global variables remain set. If you | |
2758 | rerun the program, you will need to set all such watchpoints again. One | |
2759 | way of doing that would be to set a code breakpoint at the entry to the | |
2760 | @code{main} function and when it breaks, set all the watchpoints. | |
2761 | ||
c906108c SS |
2762 | @quotation |
2763 | @cindex watchpoints and threads | |
2764 | @cindex threads and watchpoints | |
c906108c SS |
2765 | @emph{Warning:} In multi-thread programs, watchpoints have only limited |
2766 | usefulness. With the current watchpoint implementation, @value{GDBN} | |
2767 | can only watch the value of an expression @emph{in a single thread}. If | |
2768 | you are confident that the expression can only change due to the current | |
2769 | thread's activity (and if you are also confident that no other thread | |
2770 | can become current), then you can use watchpoints as usual. However, | |
2771 | @value{GDBN} may not notice when a non-current thread's activity changes | |
2772 | the expression. | |
53a5351d | 2773 | |
d4f3574e | 2774 | @c FIXME: this is almost identical to the previous paragraph. |
53a5351d JM |
2775 | @emph{HP-UX Warning:} In multi-thread programs, software watchpoints |
2776 | have only limited usefulness. If @value{GDBN} creates a software | |
2777 | watchpoint, it can only watch the value of an expression @emph{in a | |
2778 | single thread}. If you are confident that the expression can only | |
2779 | change due to the current thread's activity (and if you are also | |
2780 | confident that no other thread can become current), then you can use | |
2781 | software watchpoints as usual. However, @value{GDBN} may not notice | |
2782 | when a non-current thread's activity changes the expression. (Hardware | |
2783 | watchpoints, in contrast, watch an expression in all threads.) | |
c906108c | 2784 | @end quotation |
c906108c | 2785 | |
6d2ebf8b | 2786 | @node Set Catchpoints |
c906108c | 2787 | @subsection Setting catchpoints |
d4f3574e | 2788 | @cindex catchpoints, setting |
c906108c SS |
2789 | @cindex exception handlers |
2790 | @cindex event handling | |
2791 | ||
2792 | You can use @dfn{catchpoints} to cause the debugger to stop for certain | |
b37052ae | 2793 | kinds of program events, such as C@t{++} exceptions or the loading of a |
c906108c SS |
2794 | shared library. Use the @code{catch} command to set a catchpoint. |
2795 | ||
2796 | @table @code | |
2797 | @kindex catch | |
2798 | @item catch @var{event} | |
2799 | Stop when @var{event} occurs. @var{event} can be any of the following: | |
2800 | @table @code | |
2801 | @item throw | |
2802 | @kindex catch throw | |
b37052ae | 2803 | The throwing of a C@t{++} exception. |
c906108c SS |
2804 | |
2805 | @item catch | |
2806 | @kindex catch catch | |
b37052ae | 2807 | The catching of a C@t{++} exception. |
c906108c SS |
2808 | |
2809 | @item exec | |
2810 | @kindex catch exec | |
2811 | A call to @code{exec}. This is currently only available for HP-UX. | |
2812 | ||
2813 | @item fork | |
2814 | @kindex catch fork | |
2815 | A call to @code{fork}. This is currently only available for HP-UX. | |
2816 | ||
2817 | @item vfork | |
2818 | @kindex catch vfork | |
2819 | A call to @code{vfork}. This is currently only available for HP-UX. | |
2820 | ||
2821 | @item load | |
2822 | @itemx load @var{libname} | |
2823 | @kindex catch load | |
2824 | The dynamic loading of any shared library, or the loading of the library | |
2825 | @var{libname}. This is currently only available for HP-UX. | |
2826 | ||
2827 | @item unload | |
2828 | @itemx unload @var{libname} | |
2829 | @kindex catch unload | |
2830 | The unloading of any dynamically loaded shared library, or the unloading | |
2831 | of the library @var{libname}. This is currently only available for HP-UX. | |
2832 | @end table | |
2833 | ||
2834 | @item tcatch @var{event} | |
2835 | Set a catchpoint that is enabled only for one stop. The catchpoint is | |
2836 | automatically deleted after the first time the event is caught. | |
2837 | ||
2838 | @end table | |
2839 | ||
2840 | Use the @code{info break} command to list the current catchpoints. | |
2841 | ||
b37052ae | 2842 | There are currently some limitations to C@t{++} exception handling |
c906108c SS |
2843 | (@code{catch throw} and @code{catch catch}) in @value{GDBN}: |
2844 | ||
2845 | @itemize @bullet | |
2846 | @item | |
2847 | If you call a function interactively, @value{GDBN} normally returns | |
2848 | control to you when the function has finished executing. If the call | |
2849 | raises an exception, however, the call may bypass the mechanism that | |
2850 | returns control to you and cause your program either to abort or to | |
2851 | simply continue running until it hits a breakpoint, catches a signal | |
2852 | that @value{GDBN} is listening for, or exits. This is the case even if | |
2853 | you set a catchpoint for the exception; catchpoints on exceptions are | |
2854 | disabled within interactive calls. | |
2855 | ||
2856 | @item | |
2857 | You cannot raise an exception interactively. | |
2858 | ||
2859 | @item | |
2860 | You cannot install an exception handler interactively. | |
2861 | @end itemize | |
2862 | ||
2863 | @cindex raise exceptions | |
2864 | Sometimes @code{catch} is not the best way to debug exception handling: | |
2865 | if you need to know exactly where an exception is raised, it is better to | |
2866 | stop @emph{before} the exception handler is called, since that way you | |
2867 | can see the stack before any unwinding takes place. If you set a | |
2868 | breakpoint in an exception handler instead, it may not be easy to find | |
2869 | out where the exception was raised. | |
2870 | ||
2871 | To stop just before an exception handler is called, you need some | |
b37052ae | 2872 | knowledge of the implementation. In the case of @sc{gnu} C@t{++}, exceptions are |
c906108c SS |
2873 | raised by calling a library function named @code{__raise_exception} |
2874 | which has the following ANSI C interface: | |
2875 | ||
2876 | @example | |
2877 | /* @var{addr} is where the exception identifier is stored. | |
d4f3574e SS |
2878 | @var{id} is the exception identifier. */ |
2879 | void __raise_exception (void **addr, void *id); | |
c906108c SS |
2880 | @end example |
2881 | ||
2882 | @noindent | |
2883 | To make the debugger catch all exceptions before any stack | |
2884 | unwinding takes place, set a breakpoint on @code{__raise_exception} | |
2885 | (@pxref{Breakpoints, ,Breakpoints; watchpoints; and exceptions}). | |
2886 | ||
2887 | With a conditional breakpoint (@pxref{Conditions, ,Break conditions}) | |
2888 | that depends on the value of @var{id}, you can stop your program when | |
2889 | a specific exception is raised. You can use multiple conditional | |
2890 | breakpoints to stop your program when any of a number of exceptions are | |
2891 | raised. | |
2892 | ||
2893 | ||
6d2ebf8b | 2894 | @node Delete Breaks |
c906108c SS |
2895 | @subsection Deleting breakpoints |
2896 | ||
2897 | @cindex clearing breakpoints, watchpoints, catchpoints | |
2898 | @cindex deleting breakpoints, watchpoints, catchpoints | |
2899 | It is often necessary to eliminate a breakpoint, watchpoint, or | |
2900 | catchpoint once it has done its job and you no longer want your program | |
2901 | to stop there. This is called @dfn{deleting} the breakpoint. A | |
2902 | breakpoint that has been deleted no longer exists; it is forgotten. | |
2903 | ||
2904 | With the @code{clear} command you can delete breakpoints according to | |
2905 | where they are in your program. With the @code{delete} command you can | |
2906 | delete individual breakpoints, watchpoints, or catchpoints by specifying | |
2907 | their breakpoint numbers. | |
2908 | ||
2909 | It is not necessary to delete a breakpoint to proceed past it. @value{GDBN} | |
2910 | automatically ignores breakpoints on the first instruction to be executed | |
2911 | when you continue execution without changing the execution address. | |
2912 | ||
2913 | @table @code | |
2914 | @kindex clear | |
2915 | @item clear | |
2916 | Delete any breakpoints at the next instruction to be executed in the | |
2917 | selected stack frame (@pxref{Selection, ,Selecting a frame}). When | |
2918 | the innermost frame is selected, this is a good way to delete a | |
2919 | breakpoint where your program just stopped. | |
2920 | ||
2921 | @item clear @var{function} | |
2922 | @itemx clear @var{filename}:@var{function} | |
2923 | Delete any breakpoints set at entry to the function @var{function}. | |
2924 | ||
2925 | @item clear @var{linenum} | |
2926 | @itemx clear @var{filename}:@var{linenum} | |
2927 | Delete any breakpoints set at or within the code of the specified line. | |
2928 | ||
2929 | @cindex delete breakpoints | |
2930 | @kindex delete | |
41afff9a | 2931 | @kindex d @r{(@code{delete})} |
c5394b80 JM |
2932 | @item delete @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
2933 | Delete the breakpoints, watchpoints, or catchpoints of the breakpoint | |
2934 | ranges specified as arguments. If no argument is specified, delete all | |
c906108c SS |
2935 | breakpoints (@value{GDBN} asks confirmation, unless you have @code{set |
2936 | confirm off}). You can abbreviate this command as @code{d}. | |
2937 | @end table | |
2938 | ||
6d2ebf8b | 2939 | @node Disabling |
c906108c SS |
2940 | @subsection Disabling breakpoints |
2941 | ||
2942 | @kindex disable breakpoints | |
2943 | @kindex enable breakpoints | |
2944 | Rather than deleting a breakpoint, watchpoint, or catchpoint, you might | |
2945 | prefer to @dfn{disable} it. This makes the breakpoint inoperative as if | |
2946 | it had been deleted, but remembers the information on the breakpoint so | |
2947 | that you can @dfn{enable} it again later. | |
2948 | ||
2949 | You disable and enable breakpoints, watchpoints, and catchpoints with | |
2950 | the @code{enable} and @code{disable} commands, optionally specifying one | |
2951 | or more breakpoint numbers as arguments. Use @code{info break} or | |
2952 | @code{info watch} to print a list of breakpoints, watchpoints, and | |
2953 | catchpoints if you do not know which numbers to use. | |
2954 | ||
2955 | A breakpoint, watchpoint, or catchpoint can have any of four different | |
2956 | states of enablement: | |
2957 | ||
2958 | @itemize @bullet | |
2959 | @item | |
2960 | Enabled. The breakpoint stops your program. A breakpoint set | |
2961 | with the @code{break} command starts out in this state. | |
2962 | @item | |
2963 | Disabled. The breakpoint has no effect on your program. | |
2964 | @item | |
2965 | Enabled once. The breakpoint stops your program, but then becomes | |
d4f3574e | 2966 | disabled. |
c906108c SS |
2967 | @item |
2968 | Enabled for deletion. The breakpoint stops your program, but | |
d4f3574e SS |
2969 | immediately after it does so it is deleted permanently. A breakpoint |
2970 | set with the @code{tbreak} command starts out in this state. | |
c906108c SS |
2971 | @end itemize |
2972 | ||
2973 | You can use the following commands to enable or disable breakpoints, | |
2974 | watchpoints, and catchpoints: | |
2975 | ||
2976 | @table @code | |
2977 | @kindex disable breakpoints | |
2978 | @kindex disable | |
41afff9a | 2979 | @kindex dis @r{(@code{disable})} |
c5394b80 | 2980 | @item disable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
2981 | Disable the specified breakpoints---or all breakpoints, if none are |
2982 | listed. A disabled breakpoint has no effect but is not forgotten. All | |
2983 | options such as ignore-counts, conditions and commands are remembered in | |
2984 | case the breakpoint is enabled again later. You may abbreviate | |
2985 | @code{disable} as @code{dis}. | |
2986 | ||
2987 | @kindex enable breakpoints | |
2988 | @kindex enable | |
c5394b80 | 2989 | @item enable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
2990 | Enable the specified breakpoints (or all defined breakpoints). They |
2991 | become effective once again in stopping your program. | |
2992 | ||
c5394b80 | 2993 | @item enable @r{[}breakpoints@r{]} once @var{range}@dots{} |
c906108c SS |
2994 | Enable the specified breakpoints temporarily. @value{GDBN} disables any |
2995 | of these breakpoints immediately after stopping your program. | |
2996 | ||
c5394b80 | 2997 | @item enable @r{[}breakpoints@r{]} delete @var{range}@dots{} |
c906108c SS |
2998 | Enable the specified breakpoints to work once, then die. @value{GDBN} |
2999 | deletes any of these breakpoints as soon as your program stops there. | |
3000 | @end table | |
3001 | ||
d4f3574e SS |
3002 | @c FIXME: I think the following ``Except for [...] @code{tbreak}'' is |
3003 | @c confusing: tbreak is also initially enabled. | |
c906108c SS |
3004 | Except for a breakpoint set with @code{tbreak} (@pxref{Set Breaks, |
3005 | ,Setting breakpoints}), breakpoints that you set are initially enabled; | |
3006 | subsequently, they become disabled or enabled only when you use one of | |
3007 | the commands above. (The command @code{until} can set and delete a | |
3008 | breakpoint of its own, but it does not change the state of your other | |
3009 | breakpoints; see @ref{Continuing and Stepping, ,Continuing and | |
3010 | stepping}.) | |
3011 | ||
6d2ebf8b | 3012 | @node Conditions |
c906108c SS |
3013 | @subsection Break conditions |
3014 | @cindex conditional breakpoints | |
3015 | @cindex breakpoint conditions | |
3016 | ||
3017 | @c FIXME what is scope of break condition expr? Context where wanted? | |
5d161b24 | 3018 | @c in particular for a watchpoint? |
c906108c SS |
3019 | The simplest sort of breakpoint breaks every time your program reaches a |
3020 | specified place. You can also specify a @dfn{condition} for a | |
3021 | breakpoint. A condition is just a Boolean expression in your | |
3022 | programming language (@pxref{Expressions, ,Expressions}). A breakpoint with | |
3023 | a condition evaluates the expression each time your program reaches it, | |
3024 | and your program stops only if the condition is @emph{true}. | |
3025 | ||
3026 | This is the converse of using assertions for program validation; in that | |
3027 | situation, you want to stop when the assertion is violated---that is, | |
3028 | when the condition is false. In C, if you want to test an assertion expressed | |
3029 | by the condition @var{assert}, you should set the condition | |
3030 | @samp{! @var{assert}} on the appropriate breakpoint. | |
3031 | ||
3032 | Conditions are also accepted for watchpoints; you may not need them, | |
3033 | since a watchpoint is inspecting the value of an expression anyhow---but | |
3034 | it might be simpler, say, to just set a watchpoint on a variable name, | |
3035 | and specify a condition that tests whether the new value is an interesting | |
3036 | one. | |
3037 | ||
3038 | Break conditions can have side effects, and may even call functions in | |
3039 | your program. This can be useful, for example, to activate functions | |
3040 | that log program progress, or to use your own print functions to | |
3041 | format special data structures. The effects are completely predictable | |
3042 | unless there is another enabled breakpoint at the same address. (In | |
3043 | that case, @value{GDBN} might see the other breakpoint first and stop your | |
3044 | program without checking the condition of this one.) Note that | |
d4f3574e SS |
3045 | breakpoint commands are usually more convenient and flexible than break |
3046 | conditions for the | |
c906108c SS |
3047 | purpose of performing side effects when a breakpoint is reached |
3048 | (@pxref{Break Commands, ,Breakpoint command lists}). | |
3049 | ||
3050 | Break conditions can be specified when a breakpoint is set, by using | |
3051 | @samp{if} in the arguments to the @code{break} command. @xref{Set | |
3052 | Breaks, ,Setting breakpoints}. They can also be changed at any time | |
3053 | with the @code{condition} command. | |
53a5351d | 3054 | |
c906108c SS |
3055 | You can also use the @code{if} keyword with the @code{watch} command. |
3056 | The @code{catch} command does not recognize the @code{if} keyword; | |
3057 | @code{condition} is the only way to impose a further condition on a | |
3058 | catchpoint. | |
c906108c SS |
3059 | |
3060 | @table @code | |
3061 | @kindex condition | |
3062 | @item condition @var{bnum} @var{expression} | |
3063 | Specify @var{expression} as the break condition for breakpoint, | |
3064 | watchpoint, or catchpoint number @var{bnum}. After you set a condition, | |
3065 | breakpoint @var{bnum} stops your program only if the value of | |
3066 | @var{expression} is true (nonzero, in C). When you use | |
3067 | @code{condition}, @value{GDBN} checks @var{expression} immediately for | |
3068 | syntactic correctness, and to determine whether symbols in it have | |
d4f3574e SS |
3069 | referents in the context of your breakpoint. If @var{expression} uses |
3070 | symbols not referenced in the context of the breakpoint, @value{GDBN} | |
3071 | prints an error message: | |
3072 | ||
3073 | @example | |
3074 | No symbol "foo" in current context. | |
3075 | @end example | |
3076 | ||
3077 | @noindent | |
c906108c SS |
3078 | @value{GDBN} does |
3079 | not actually evaluate @var{expression} at the time the @code{condition} | |
d4f3574e SS |
3080 | command (or a command that sets a breakpoint with a condition, like |
3081 | @code{break if @dots{}}) is given, however. @xref{Expressions, ,Expressions}. | |
c906108c SS |
3082 | |
3083 | @item condition @var{bnum} | |
3084 | Remove the condition from breakpoint number @var{bnum}. It becomes | |
3085 | an ordinary unconditional breakpoint. | |
3086 | @end table | |
3087 | ||
3088 | @cindex ignore count (of breakpoint) | |
3089 | A special case of a breakpoint condition is to stop only when the | |
3090 | breakpoint has been reached a certain number of times. This is so | |
3091 | useful that there is a special way to do it, using the @dfn{ignore | |
3092 | count} of the breakpoint. Every breakpoint has an ignore count, which | |
3093 | is an integer. Most of the time, the ignore count is zero, and | |
3094 | therefore has no effect. But if your program reaches a breakpoint whose | |
3095 | ignore count is positive, then instead of stopping, it just decrements | |
3096 | the ignore count by one and continues. As a result, if the ignore count | |
3097 | value is @var{n}, the breakpoint does not stop the next @var{n} times | |
3098 | your program reaches it. | |
3099 | ||
3100 | @table @code | |
3101 | @kindex ignore | |
3102 | @item ignore @var{bnum} @var{count} | |
3103 | Set the ignore count of breakpoint number @var{bnum} to @var{count}. | |
3104 | The next @var{count} times the breakpoint is reached, your program's | |
3105 | execution does not stop; other than to decrement the ignore count, @value{GDBN} | |
3106 | takes no action. | |
3107 | ||
3108 | To make the breakpoint stop the next time it is reached, specify | |
3109 | a count of zero. | |
3110 | ||
3111 | When you use @code{continue} to resume execution of your program from a | |
3112 | breakpoint, you can specify an ignore count directly as an argument to | |
3113 | @code{continue}, rather than using @code{ignore}. @xref{Continuing and | |
3114 | Stepping,,Continuing and stepping}. | |
3115 | ||
3116 | If a breakpoint has a positive ignore count and a condition, the | |
3117 | condition is not checked. Once the ignore count reaches zero, | |
3118 | @value{GDBN} resumes checking the condition. | |
3119 | ||
3120 | You could achieve the effect of the ignore count with a condition such | |
3121 | as @w{@samp{$foo-- <= 0}} using a debugger convenience variable that | |
3122 | is decremented each time. @xref{Convenience Vars, ,Convenience | |
3123 | variables}. | |
3124 | @end table | |
3125 | ||
3126 | Ignore counts apply to breakpoints, watchpoints, and catchpoints. | |
3127 | ||
3128 | ||
6d2ebf8b | 3129 | @node Break Commands |
c906108c SS |
3130 | @subsection Breakpoint command lists |
3131 | ||
3132 | @cindex breakpoint commands | |
3133 | You can give any breakpoint (or watchpoint or catchpoint) a series of | |
3134 | commands to execute when your program stops due to that breakpoint. For | |
3135 | example, you might want to print the values of certain expressions, or | |
3136 | enable other breakpoints. | |
3137 | ||
3138 | @table @code | |
3139 | @kindex commands | |
3140 | @kindex end | |
3141 | @item commands @r{[}@var{bnum}@r{]} | |
3142 | @itemx @dots{} @var{command-list} @dots{} | |
3143 | @itemx end | |
3144 | Specify a list of commands for breakpoint number @var{bnum}. The commands | |
3145 | themselves appear on the following lines. Type a line containing just | |
3146 | @code{end} to terminate the commands. | |
3147 | ||
3148 | To remove all commands from a breakpoint, type @code{commands} and | |
3149 | follow it immediately with @code{end}; that is, give no commands. | |
3150 | ||
3151 | With no @var{bnum} argument, @code{commands} refers to the last | |
3152 | breakpoint, watchpoint, or catchpoint set (not to the breakpoint most | |
3153 | recently encountered). | |
3154 | @end table | |
3155 | ||
3156 | Pressing @key{RET} as a means of repeating the last @value{GDBN} command is | |
3157 | disabled within a @var{command-list}. | |
3158 | ||
3159 | You can use breakpoint commands to start your program up again. Simply | |
3160 | use the @code{continue} command, or @code{step}, or any other command | |
3161 | that resumes execution. | |
3162 | ||
3163 | Any other commands in the command list, after a command that resumes | |
3164 | execution, are ignored. This is because any time you resume execution | |
3165 | (even with a simple @code{next} or @code{step}), you may encounter | |
3166 | another breakpoint---which could have its own command list, leading to | |
3167 | ambiguities about which list to execute. | |
3168 | ||
3169 | @kindex silent | |
3170 | If the first command you specify in a command list is @code{silent}, the | |
3171 | usual message about stopping at a breakpoint is not printed. This may | |
3172 | be desirable for breakpoints that are to print a specific message and | |
3173 | then continue. If none of the remaining commands print anything, you | |
3174 | see no sign that the breakpoint was reached. @code{silent} is | |
3175 | meaningful only at the beginning of a breakpoint command list. | |
3176 | ||
3177 | The commands @code{echo}, @code{output}, and @code{printf} allow you to | |
3178 | print precisely controlled output, and are often useful in silent | |
3179 | breakpoints. @xref{Output, ,Commands for controlled output}. | |
3180 | ||
3181 | For example, here is how you could use breakpoint commands to print the | |
3182 | value of @code{x} at entry to @code{foo} whenever @code{x} is positive. | |
3183 | ||
3184 | @example | |
3185 | break foo if x>0 | |
3186 | commands | |
3187 | silent | |
3188 | printf "x is %d\n",x | |
3189 | cont | |
3190 | end | |
3191 | @end example | |
3192 | ||
3193 | One application for breakpoint commands is to compensate for one bug so | |
3194 | you can test for another. Put a breakpoint just after the erroneous line | |
3195 | of code, give it a condition to detect the case in which something | |
3196 | erroneous has been done, and give it commands to assign correct values | |
3197 | to any variables that need them. End with the @code{continue} command | |
3198 | so that your program does not stop, and start with the @code{silent} | |
3199 | command so that no output is produced. Here is an example: | |
3200 | ||
3201 | @example | |
3202 | break 403 | |
3203 | commands | |
3204 | silent | |
3205 | set x = y + 4 | |
3206 | cont | |
3207 | end | |
3208 | @end example | |
3209 | ||
6d2ebf8b | 3210 | @node Breakpoint Menus |
c906108c SS |
3211 | @subsection Breakpoint menus |
3212 | @cindex overloading | |
3213 | @cindex symbol overloading | |
3214 | ||
b37052ae | 3215 | Some programming languages (notably C@t{++}) permit a single function name |
c906108c SS |
3216 | to be defined several times, for application in different contexts. |
3217 | This is called @dfn{overloading}. When a function name is overloaded, | |
3218 | @samp{break @var{function}} is not enough to tell @value{GDBN} where you want | |
3219 | a breakpoint. If you realize this is a problem, you can use | |
3220 | something like @samp{break @var{function}(@var{types})} to specify which | |
3221 | particular version of the function you want. Otherwise, @value{GDBN} offers | |
3222 | you a menu of numbered choices for different possible breakpoints, and | |
3223 | waits for your selection with the prompt @samp{>}. The first two | |
3224 | options are always @samp{[0] cancel} and @samp{[1] all}. Typing @kbd{1} | |
3225 | sets a breakpoint at each definition of @var{function}, and typing | |
3226 | @kbd{0} aborts the @code{break} command without setting any new | |
3227 | breakpoints. | |
3228 | ||
3229 | For example, the following session excerpt shows an attempt to set a | |
3230 | breakpoint at the overloaded symbol @code{String::after}. | |
3231 | We choose three particular definitions of that function name: | |
3232 | ||
3233 | @c FIXME! This is likely to change to show arg type lists, at least | |
3234 | @smallexample | |
3235 | @group | |
3236 | (@value{GDBP}) b String::after | |
3237 | [0] cancel | |
3238 | [1] all | |
3239 | [2] file:String.cc; line number:867 | |
3240 | [3] file:String.cc; line number:860 | |
3241 | [4] file:String.cc; line number:875 | |
3242 | [5] file:String.cc; line number:853 | |
3243 | [6] file:String.cc; line number:846 | |
3244 | [7] file:String.cc; line number:735 | |
3245 | > 2 4 6 | |
3246 | Breakpoint 1 at 0xb26c: file String.cc, line 867. | |
3247 | Breakpoint 2 at 0xb344: file String.cc, line 875. | |
3248 | Breakpoint 3 at 0xafcc: file String.cc, line 846. | |
3249 | Multiple breakpoints were set. | |
3250 | Use the "delete" command to delete unwanted | |
3251 | breakpoints. | |
3252 | (@value{GDBP}) | |
3253 | @end group | |
3254 | @end smallexample | |
c906108c SS |
3255 | |
3256 | @c @ifclear BARETARGET | |
6d2ebf8b | 3257 | @node Error in Breakpoints |
d4f3574e | 3258 | @subsection ``Cannot insert breakpoints'' |
c906108c SS |
3259 | @c |
3260 | @c FIXME!! 14/6/95 Is there a real example of this? Let's use it. | |
3261 | @c | |
d4f3574e SS |
3262 | Under some operating systems, breakpoints cannot be used in a program if |
3263 | any other process is running that program. In this situation, | |
5d161b24 | 3264 | attempting to run or continue a program with a breakpoint causes |
d4f3574e SS |
3265 | @value{GDBN} to print an error message: |
3266 | ||
3267 | @example | |
3268 | Cannot insert breakpoints. | |
3269 | The same program may be running in another process. | |
3270 | @end example | |
3271 | ||
3272 | When this happens, you have three ways to proceed: | |
3273 | ||
3274 | @enumerate | |
3275 | @item | |
3276 | Remove or disable the breakpoints, then continue. | |
3277 | ||
3278 | @item | |
5d161b24 | 3279 | Suspend @value{GDBN}, and copy the file containing your program to a new |
d4f3574e | 3280 | name. Resume @value{GDBN} and use the @code{exec-file} command to specify |
5d161b24 | 3281 | that @value{GDBN} should run your program under that name. |
d4f3574e SS |
3282 | Then start your program again. |
3283 | ||
3284 | @item | |
3285 | Relink your program so that the text segment is nonsharable, using the | |
3286 | linker option @samp{-N}. The operating system limitation may not apply | |
3287 | to nonsharable executables. | |
3288 | @end enumerate | |
c906108c SS |
3289 | @c @end ifclear |
3290 | ||
d4f3574e SS |
3291 | A similar message can be printed if you request too many active |
3292 | hardware-assisted breakpoints and watchpoints: | |
3293 | ||
3294 | @c FIXME: the precise wording of this message may change; the relevant | |
3295 | @c source change is not committed yet (Sep 3, 1999). | |
3296 | @smallexample | |
3297 | Stopped; cannot insert breakpoints. | |
3298 | You may have requested too many hardware breakpoints and watchpoints. | |
3299 | @end smallexample | |
3300 | ||
3301 | @noindent | |
3302 | This message is printed when you attempt to resume the program, since | |
3303 | only then @value{GDBN} knows exactly how many hardware breakpoints and | |
3304 | watchpoints it needs to insert. | |
3305 | ||
3306 | When this message is printed, you need to disable or remove some of the | |
3307 | hardware-assisted breakpoints and watchpoints, and then continue. | |
3308 | ||
3309 | ||
6d2ebf8b | 3310 | @node Continuing and Stepping |
c906108c SS |
3311 | @section Continuing and stepping |
3312 | ||
3313 | @cindex stepping | |
3314 | @cindex continuing | |
3315 | @cindex resuming execution | |
3316 | @dfn{Continuing} means resuming program execution until your program | |
3317 | completes normally. In contrast, @dfn{stepping} means executing just | |
3318 | one more ``step'' of your program, where ``step'' may mean either one | |
3319 | line of source code, or one machine instruction (depending on what | |
7a292a7a SS |
3320 | particular command you use). Either when continuing or when stepping, |
3321 | your program may stop even sooner, due to a breakpoint or a signal. (If | |
d4f3574e SS |
3322 | it stops due to a signal, you may want to use @code{handle}, or use |
3323 | @samp{signal 0} to resume execution. @xref{Signals, ,Signals}.) | |
c906108c SS |
3324 | |
3325 | @table @code | |
3326 | @kindex continue | |
41afff9a EZ |
3327 | @kindex c @r{(@code{continue})} |
3328 | @kindex fg @r{(resume foreground execution)} | |
c906108c SS |
3329 | @item continue @r{[}@var{ignore-count}@r{]} |
3330 | @itemx c @r{[}@var{ignore-count}@r{]} | |
3331 | @itemx fg @r{[}@var{ignore-count}@r{]} | |
3332 | Resume program execution, at the address where your program last stopped; | |
3333 | any breakpoints set at that address are bypassed. The optional argument | |
3334 | @var{ignore-count} allows you to specify a further number of times to | |
3335 | ignore a breakpoint at this location; its effect is like that of | |
3336 | @code{ignore} (@pxref{Conditions, ,Break conditions}). | |
3337 | ||
3338 | The argument @var{ignore-count} is meaningful only when your program | |
3339 | stopped due to a breakpoint. At other times, the argument to | |
3340 | @code{continue} is ignored. | |
3341 | ||
d4f3574e SS |
3342 | The synonyms @code{c} and @code{fg} (for @dfn{foreground}, as the |
3343 | debugged program is deemed to be the foreground program) are provided | |
3344 | purely for convenience, and have exactly the same behavior as | |
3345 | @code{continue}. | |
c906108c SS |
3346 | @end table |
3347 | ||
3348 | To resume execution at a different place, you can use @code{return} | |
3349 | (@pxref{Returning, ,Returning from a function}) to go back to the | |
3350 | calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a | |
3351 | different address}) to go to an arbitrary location in your program. | |
3352 | ||
3353 | A typical technique for using stepping is to set a breakpoint | |
3354 | (@pxref{Breakpoints, ,Breakpoints; watchpoints; and catchpoints}) at the | |
3355 | beginning of the function or the section of your program where a problem | |
3356 | is believed to lie, run your program until it stops at that breakpoint, | |
3357 | and then step through the suspect area, examining the variables that are | |
3358 | interesting, until you see the problem happen. | |
3359 | ||
3360 | @table @code | |
3361 | @kindex step | |
41afff9a | 3362 | @kindex s @r{(@code{step})} |
c906108c SS |
3363 | @item step |
3364 | Continue running your program until control reaches a different source | |
3365 | line, then stop it and return control to @value{GDBN}. This command is | |
3366 | abbreviated @code{s}. | |
3367 | ||
3368 | @quotation | |
3369 | @c "without debugging information" is imprecise; actually "without line | |
3370 | @c numbers in the debugging information". (gcc -g1 has debugging info but | |
3371 | @c not line numbers). But it seems complex to try to make that | |
3372 | @c distinction here. | |
3373 | @emph{Warning:} If you use the @code{step} command while control is | |
3374 | within a function that was compiled without debugging information, | |
3375 | execution proceeds until control reaches a function that does have | |
3376 | debugging information. Likewise, it will not step into a function which | |
3377 | is compiled without debugging information. To step through functions | |
3378 | without debugging information, use the @code{stepi} command, described | |
3379 | below. | |
3380 | @end quotation | |
3381 | ||
4a92d011 EZ |
3382 | The @code{step} command only stops at the first instruction of a source |
3383 | line. This prevents the multiple stops that could otherwise occur in | |
3384 | @code{switch} statements, @code{for} loops, etc. @code{step} continues | |
3385 | to stop if a function that has debugging information is called within | |
3386 | the line. In other words, @code{step} @emph{steps inside} any functions | |
3387 | called within the line. | |
c906108c | 3388 | |
d4f3574e SS |
3389 | Also, the @code{step} command only enters a function if there is line |
3390 | number information for the function. Otherwise it acts like the | |
5d161b24 | 3391 | @code{next} command. This avoids problems when using @code{cc -gl} |
c906108c | 3392 | on MIPS machines. Previously, @code{step} entered subroutines if there |
5d161b24 | 3393 | was any debugging information about the routine. |
c906108c SS |
3394 | |
3395 | @item step @var{count} | |
3396 | Continue running as in @code{step}, but do so @var{count} times. If a | |
7a292a7a SS |
3397 | breakpoint is reached, or a signal not related to stepping occurs before |
3398 | @var{count} steps, stepping stops right away. | |
c906108c SS |
3399 | |
3400 | @kindex next | |
41afff9a | 3401 | @kindex n @r{(@code{next})} |
c906108c SS |
3402 | @item next @r{[}@var{count}@r{]} |
3403 | Continue to the next source line in the current (innermost) stack frame. | |
7a292a7a SS |
3404 | This is similar to @code{step}, but function calls that appear within |
3405 | the line of code are executed without stopping. Execution stops when | |
3406 | control reaches a different line of code at the original stack level | |
3407 | that was executing when you gave the @code{next} command. This command | |
3408 | is abbreviated @code{n}. | |
c906108c SS |
3409 | |
3410 | An argument @var{count} is a repeat count, as for @code{step}. | |
3411 | ||
3412 | ||
3413 | @c FIX ME!! Do we delete this, or is there a way it fits in with | |
3414 | @c the following paragraph? --- Vctoria | |
3415 | @c | |
3416 | @c @code{next} within a function that lacks debugging information acts like | |
3417 | @c @code{step}, but any function calls appearing within the code of the | |
3418 | @c function are executed without stopping. | |
3419 | ||
d4f3574e SS |
3420 | The @code{next} command only stops at the first instruction of a |
3421 | source line. This prevents multiple stops that could otherwise occur in | |
4a92d011 | 3422 | @code{switch} statements, @code{for} loops, etc. |
c906108c | 3423 | |
b90a5f51 CF |
3424 | @kindex set step-mode |
3425 | @item set step-mode | |
3426 | @cindex functions without line info, and stepping | |
3427 | @cindex stepping into functions with no line info | |
3428 | @itemx set step-mode on | |
4a92d011 | 3429 | The @code{set step-mode on} command causes the @code{step} command to |
b90a5f51 CF |
3430 | stop at the first instruction of a function which contains no debug line |
3431 | information rather than stepping over it. | |
3432 | ||
4a92d011 EZ |
3433 | This is useful in cases where you may be interested in inspecting the |
3434 | machine instructions of a function which has no symbolic info and do not | |
3435 | want @value{GDBN} to automatically skip over this function. | |
b90a5f51 CF |
3436 | |
3437 | @item set step-mode off | |
4a92d011 | 3438 | Causes the @code{step} command to step over any functions which contains no |
b90a5f51 CF |
3439 | debug information. This is the default. |
3440 | ||
c906108c SS |
3441 | @kindex finish |
3442 | @item finish | |
3443 | Continue running until just after function in the selected stack frame | |
3444 | returns. Print the returned value (if any). | |
3445 | ||
3446 | Contrast this with the @code{return} command (@pxref{Returning, | |
3447 | ,Returning from a function}). | |
3448 | ||
3449 | @kindex until | |
41afff9a | 3450 | @kindex u @r{(@code{until})} |
c906108c SS |
3451 | @item until |
3452 | @itemx u | |
3453 | Continue running until a source line past the current line, in the | |
3454 | current stack frame, is reached. This command is used to avoid single | |
3455 | stepping through a loop more than once. It is like the @code{next} | |
3456 | command, except that when @code{until} encounters a jump, it | |
3457 | automatically continues execution until the program counter is greater | |
3458 | than the address of the jump. | |
3459 | ||
3460 | This means that when you reach the end of a loop after single stepping | |
3461 | though it, @code{until} makes your program continue execution until it | |
3462 | exits the loop. In contrast, a @code{next} command at the end of a loop | |
3463 | simply steps back to the beginning of the loop, which forces you to step | |
3464 | through the next iteration. | |
3465 | ||
3466 | @code{until} always stops your program if it attempts to exit the current | |
3467 | stack frame. | |
3468 | ||
3469 | @code{until} may produce somewhat counterintuitive results if the order | |
3470 | of machine code does not match the order of the source lines. For | |
3471 | example, in the following excerpt from a debugging session, the @code{f} | |
3472 | (@code{frame}) command shows that execution is stopped at line | |
3473 | @code{206}; yet when we use @code{until}, we get to line @code{195}: | |
3474 | ||
3475 | @example | |
3476 | (@value{GDBP}) f | |
3477 | #0 main (argc=4, argv=0xf7fffae8) at m4.c:206 | |
3478 | 206 expand_input(); | |
3479 | (@value{GDBP}) until | |
3480 | 195 for ( ; argc > 0; NEXTARG) @{ | |
3481 | @end example | |
3482 | ||
3483 | This happened because, for execution efficiency, the compiler had | |
3484 | generated code for the loop closure test at the end, rather than the | |
3485 | start, of the loop---even though the test in a C @code{for}-loop is | |
3486 | written before the body of the loop. The @code{until} command appeared | |
3487 | to step back to the beginning of the loop when it advanced to this | |
3488 | expression; however, it has not really gone to an earlier | |
3489 | statement---not in terms of the actual machine code. | |
3490 | ||
3491 | @code{until} with no argument works by means of single | |
3492 | instruction stepping, and hence is slower than @code{until} with an | |
3493 | argument. | |
3494 | ||
3495 | @item until @var{location} | |
3496 | @itemx u @var{location} | |
3497 | Continue running your program until either the specified location is | |
3498 | reached, or the current stack frame returns. @var{location} is any of | |
3499 | the forms of argument acceptable to @code{break} (@pxref{Set Breaks, | |
3500 | ,Setting breakpoints}). This form of the command uses breakpoints, | |
3501 | and hence is quicker than @code{until} without an argument. | |
3502 | ||
3503 | @kindex stepi | |
41afff9a | 3504 | @kindex si @r{(@code{stepi})} |
c906108c | 3505 | @item stepi |
96a2c332 | 3506 | @itemx stepi @var{arg} |
c906108c SS |
3507 | @itemx si |
3508 | Execute one machine instruction, then stop and return to the debugger. | |
3509 | ||
3510 | It is often useful to do @samp{display/i $pc} when stepping by machine | |
3511 | instructions. This makes @value{GDBN} automatically display the next | |
3512 | instruction to be executed, each time your program stops. @xref{Auto | |
3513 | Display,, Automatic display}. | |
3514 | ||
3515 | An argument is a repeat count, as in @code{step}. | |
3516 | ||
3517 | @need 750 | |
3518 | @kindex nexti | |
41afff9a | 3519 | @kindex ni @r{(@code{nexti})} |
c906108c | 3520 | @item nexti |
96a2c332 | 3521 | @itemx nexti @var{arg} |
c906108c SS |
3522 | @itemx ni |
3523 | Execute one machine instruction, but if it is a function call, | |
3524 | proceed until the function returns. | |
3525 | ||
3526 | An argument is a repeat count, as in @code{next}. | |
3527 | @end table | |
3528 | ||
6d2ebf8b | 3529 | @node Signals |
c906108c SS |
3530 | @section Signals |
3531 | @cindex signals | |
3532 | ||
3533 | A signal is an asynchronous event that can happen in a program. The | |
3534 | operating system defines the possible kinds of signals, and gives each | |
3535 | kind a name and a number. For example, in Unix @code{SIGINT} is the | |
d4f3574e | 3536 | signal a program gets when you type an interrupt character (often @kbd{C-c}); |
c906108c SS |
3537 | @code{SIGSEGV} is the signal a program gets from referencing a place in |
3538 | memory far away from all the areas in use; @code{SIGALRM} occurs when | |
3539 | the alarm clock timer goes off (which happens only if your program has | |
3540 | requested an alarm). | |
3541 | ||
3542 | @cindex fatal signals | |
3543 | Some signals, including @code{SIGALRM}, are a normal part of the | |
3544 | functioning of your program. Others, such as @code{SIGSEGV}, indicate | |
d4f3574e | 3545 | errors; these signals are @dfn{fatal} (they kill your program immediately) if the |
c906108c SS |
3546 | program has not specified in advance some other way to handle the signal. |
3547 | @code{SIGINT} does not indicate an error in your program, but it is normally | |
3548 | fatal so it can carry out the purpose of the interrupt: to kill the program. | |
3549 | ||
3550 | @value{GDBN} has the ability to detect any occurrence of a signal in your | |
3551 | program. You can tell @value{GDBN} in advance what to do for each kind of | |
3552 | signal. | |
3553 | ||
3554 | @cindex handling signals | |
24f93129 EZ |
3555 | Normally, @value{GDBN} is set up to let the non-erroneous signals like |
3556 | @code{SIGALRM} be silently passed to your program | |
3557 | (so as not to interfere with their role in the program's functioning) | |
c906108c SS |
3558 | but to stop your program immediately whenever an error signal happens. |
3559 | You can change these settings with the @code{handle} command. | |
3560 | ||
3561 | @table @code | |
3562 | @kindex info signals | |
3563 | @item info signals | |
96a2c332 | 3564 | @itemx info handle |
c906108c SS |
3565 | Print a table of all the kinds of signals and how @value{GDBN} has been told to |
3566 | handle each one. You can use this to see the signal numbers of all | |
3567 | the defined types of signals. | |
3568 | ||
d4f3574e | 3569 | @code{info handle} is an alias for @code{info signals}. |
c906108c SS |
3570 | |
3571 | @kindex handle | |
3572 | @item handle @var{signal} @var{keywords}@dots{} | |
5ece1a18 EZ |
3573 | Change the way @value{GDBN} handles signal @var{signal}. @var{signal} |
3574 | can be the number of a signal or its name (with or without the | |
24f93129 | 3575 | @samp{SIG} at the beginning); a list of signal numbers of the form |
5ece1a18 EZ |
3576 | @samp{@var{low}-@var{high}}; or the word @samp{all}, meaning all the |
3577 | known signals. The @var{keywords} say what change to make. | |
c906108c SS |
3578 | @end table |
3579 | ||
3580 | @c @group | |
3581 | The keywords allowed by the @code{handle} command can be abbreviated. | |
3582 | Their full names are: | |
3583 | ||
3584 | @table @code | |
3585 | @item nostop | |
3586 | @value{GDBN} should not stop your program when this signal happens. It may | |
3587 | still print a message telling you that the signal has come in. | |
3588 | ||
3589 | @item stop | |
3590 | @value{GDBN} should stop your program when this signal happens. This implies | |
3591 | the @code{print} keyword as well. | |
3592 | ||
3593 | @item print | |
3594 | @value{GDBN} should print a message when this signal happens. | |
3595 | ||
3596 | @item noprint | |
3597 | @value{GDBN} should not mention the occurrence of the signal at all. This | |
3598 | implies the @code{nostop} keyword as well. | |
3599 | ||
3600 | @item pass | |
5ece1a18 | 3601 | @itemx noignore |
c906108c SS |
3602 | @value{GDBN} should allow your program to see this signal; your program |
3603 | can handle the signal, or else it may terminate if the signal is fatal | |
5ece1a18 | 3604 | and not handled. @code{pass} and @code{noignore} are synonyms. |
c906108c SS |
3605 | |
3606 | @item nopass | |
5ece1a18 | 3607 | @itemx ignore |
c906108c | 3608 | @value{GDBN} should not allow your program to see this signal. |
5ece1a18 | 3609 | @code{nopass} and @code{ignore} are synonyms. |
c906108c SS |
3610 | @end table |
3611 | @c @end group | |
3612 | ||
d4f3574e SS |
3613 | When a signal stops your program, the signal is not visible to the |
3614 | program until you | |
c906108c SS |
3615 | continue. Your program sees the signal then, if @code{pass} is in |
3616 | effect for the signal in question @emph{at that time}. In other words, | |
3617 | after @value{GDBN} reports a signal, you can use the @code{handle} | |
3618 | command with @code{pass} or @code{nopass} to control whether your | |
3619 | program sees that signal when you continue. | |
3620 | ||
24f93129 EZ |
3621 | The default is set to @code{nostop}, @code{noprint}, @code{pass} for |
3622 | non-erroneous signals such as @code{SIGALRM}, @code{SIGWINCH} and | |
3623 | @code{SIGCHLD}, and to @code{stop}, @code{print}, @code{pass} for the | |
3624 | erroneous signals. | |
3625 | ||
c906108c SS |
3626 | You can also use the @code{signal} command to prevent your program from |
3627 | seeing a signal, or cause it to see a signal it normally would not see, | |
3628 | or to give it any signal at any time. For example, if your program stopped | |
3629 | due to some sort of memory reference error, you might store correct | |
3630 | values into the erroneous variables and continue, hoping to see more | |
3631 | execution; but your program would probably terminate immediately as | |
3632 | a result of the fatal signal once it saw the signal. To prevent this, | |
3633 | you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your | |
5d161b24 | 3634 | program a signal}. |
c906108c | 3635 | |
6d2ebf8b | 3636 | @node Thread Stops |
c906108c SS |
3637 | @section Stopping and starting multi-thread programs |
3638 | ||
3639 | When your program has multiple threads (@pxref{Threads,, Debugging | |
3640 | programs with multiple threads}), you can choose whether to set | |
3641 | breakpoints on all threads, or on a particular thread. | |
3642 | ||
3643 | @table @code | |
3644 | @cindex breakpoints and threads | |
3645 | @cindex thread breakpoints | |
3646 | @kindex break @dots{} thread @var{threadno} | |
3647 | @item break @var{linespec} thread @var{threadno} | |
3648 | @itemx break @var{linespec} thread @var{threadno} if @dots{} | |
3649 | @var{linespec} specifies source lines; there are several ways of | |
3650 | writing them, but the effect is always to specify some source line. | |
3651 | ||
3652 | Use the qualifier @samp{thread @var{threadno}} with a breakpoint command | |
3653 | to specify that you only want @value{GDBN} to stop the program when a | |
3654 | particular thread reaches this breakpoint. @var{threadno} is one of the | |
3655 | numeric thread identifiers assigned by @value{GDBN}, shown in the first | |
3656 | column of the @samp{info threads} display. | |
3657 | ||
3658 | If you do not specify @samp{thread @var{threadno}} when you set a | |
3659 | breakpoint, the breakpoint applies to @emph{all} threads of your | |
3660 | program. | |
3661 | ||
3662 | You can use the @code{thread} qualifier on conditional breakpoints as | |
3663 | well; in this case, place @samp{thread @var{threadno}} before the | |
3664 | breakpoint condition, like this: | |
3665 | ||
3666 | @smallexample | |
2df3850c | 3667 | (@value{GDBP}) break frik.c:13 thread 28 if bartab > lim |
c906108c SS |
3668 | @end smallexample |
3669 | ||
3670 | @end table | |
3671 | ||
3672 | @cindex stopped threads | |
3673 | @cindex threads, stopped | |
3674 | Whenever your program stops under @value{GDBN} for any reason, | |
3675 | @emph{all} threads of execution stop, not just the current thread. This | |
3676 | allows you to examine the overall state of the program, including | |
3677 | switching between threads, without worrying that things may change | |
3678 | underfoot. | |
3679 | ||
3680 | @cindex continuing threads | |
3681 | @cindex threads, continuing | |
3682 | Conversely, whenever you restart the program, @emph{all} threads start | |
3683 | executing. @emph{This is true even when single-stepping} with commands | |
5d161b24 | 3684 | like @code{step} or @code{next}. |
c906108c SS |
3685 | |
3686 | In particular, @value{GDBN} cannot single-step all threads in lockstep. | |
3687 | Since thread scheduling is up to your debugging target's operating | |
3688 | system (not controlled by @value{GDBN}), other threads may | |
3689 | execute more than one statement while the current thread completes a | |
3690 | single step. Moreover, in general other threads stop in the middle of a | |
3691 | statement, rather than at a clean statement boundary, when the program | |
3692 | stops. | |
3693 | ||
3694 | You might even find your program stopped in another thread after | |
3695 | continuing or even single-stepping. This happens whenever some other | |
3696 | thread runs into a breakpoint, a signal, or an exception before the | |
3697 | first thread completes whatever you requested. | |
3698 | ||
3699 | On some OSes, you can lock the OS scheduler and thus allow only a single | |
3700 | thread to run. | |
3701 | ||
3702 | @table @code | |
3703 | @item set scheduler-locking @var{mode} | |
3704 | Set the scheduler locking mode. If it is @code{off}, then there is no | |
3705 | locking and any thread may run at any time. If @code{on}, then only the | |
3706 | current thread may run when the inferior is resumed. The @code{step} | |
3707 | mode optimizes for single-stepping. It stops other threads from | |
3708 | ``seizing the prompt'' by preempting the current thread while you are | |
3709 | stepping. Other threads will only rarely (or never) get a chance to run | |
d4f3574e | 3710 | when you step. They are more likely to run when you @samp{next} over a |
c906108c | 3711 | function call, and they are completely free to run when you use commands |
d4f3574e | 3712 | like @samp{continue}, @samp{until}, or @samp{finish}. However, unless another |
c906108c | 3713 | thread hits a breakpoint during its timeslice, they will never steal the |
2df3850c | 3714 | @value{GDBN} prompt away from the thread that you are debugging. |
c906108c SS |
3715 | |
3716 | @item show scheduler-locking | |
3717 | Display the current scheduler locking mode. | |
3718 | @end table | |
3719 | ||
c906108c | 3720 | |
6d2ebf8b | 3721 | @node Stack |
c906108c SS |
3722 | @chapter Examining the Stack |
3723 | ||
3724 | When your program has stopped, the first thing you need to know is where it | |
3725 | stopped and how it got there. | |
3726 | ||
3727 | @cindex call stack | |
5d161b24 DB |
3728 | Each time your program performs a function call, information about the call |
3729 | is generated. | |
3730 | That information includes the location of the call in your program, | |
3731 | the arguments of the call, | |
c906108c | 3732 | and the local variables of the function being called. |
5d161b24 | 3733 | The information is saved in a block of data called a @dfn{stack frame}. |
c906108c SS |
3734 | The stack frames are allocated in a region of memory called the @dfn{call |
3735 | stack}. | |
3736 | ||
3737 | When your program stops, the @value{GDBN} commands for examining the | |
3738 | stack allow you to see all of this information. | |
3739 | ||
3740 | @cindex selected frame | |
3741 | One of the stack frames is @dfn{selected} by @value{GDBN} and many | |
3742 | @value{GDBN} commands refer implicitly to the selected frame. In | |
3743 | particular, whenever you ask @value{GDBN} for the value of a variable in | |
3744 | your program, the value is found in the selected frame. There are | |
3745 | special @value{GDBN} commands to select whichever frame you are | |
3746 | interested in. @xref{Selection, ,Selecting a frame}. | |
3747 | ||
3748 | When your program stops, @value{GDBN} automatically selects the | |
5d161b24 | 3749 | currently executing frame and describes it briefly, similar to the |
c906108c SS |
3750 | @code{frame} command (@pxref{Frame Info, ,Information about a frame}). |
3751 | ||
3752 | @menu | |
3753 | * Frames:: Stack frames | |
3754 | * Backtrace:: Backtraces | |
3755 | * Selection:: Selecting a frame | |
3756 | * Frame Info:: Information on a frame | |
c906108c SS |
3757 | |
3758 | @end menu | |
3759 | ||
6d2ebf8b | 3760 | @node Frames |
c906108c SS |
3761 | @section Stack frames |
3762 | ||
d4f3574e | 3763 | @cindex frame, definition |
c906108c SS |
3764 | @cindex stack frame |
3765 | The call stack is divided up into contiguous pieces called @dfn{stack | |
3766 | frames}, or @dfn{frames} for short; each frame is the data associated | |
3767 | with one call to one function. The frame contains the arguments given | |
3768 | to the function, the function's local variables, and the address at | |
3769 | which the function is executing. | |
3770 | ||
3771 | @cindex initial frame | |
3772 | @cindex outermost frame | |
3773 | @cindex innermost frame | |
3774 | When your program is started, the stack has only one frame, that of the | |
3775 | function @code{main}. This is called the @dfn{initial} frame or the | |
3776 | @dfn{outermost} frame. Each time a function is called, a new frame is | |
3777 | made. Each time a function returns, the frame for that function invocation | |
3778 | is eliminated. If a function is recursive, there can be many frames for | |
3779 | the same function. The frame for the function in which execution is | |
3780 | actually occurring is called the @dfn{innermost} frame. This is the most | |
3781 | recently created of all the stack frames that still exist. | |
3782 | ||
3783 | @cindex frame pointer | |
3784 | Inside your program, stack frames are identified by their addresses. A | |
3785 | stack frame consists of many bytes, each of which has its own address; each | |
3786 | kind of computer has a convention for choosing one byte whose | |
3787 | address serves as the address of the frame. Usually this address is kept | |
3788 | in a register called the @dfn{frame pointer register} while execution is | |
3789 | going on in that frame. | |
3790 | ||
3791 | @cindex frame number | |
3792 | @value{GDBN} assigns numbers to all existing stack frames, starting with | |
3793 | zero for the innermost frame, one for the frame that called it, | |
3794 | and so on upward. These numbers do not really exist in your program; | |
3795 | they are assigned by @value{GDBN} to give you a way of designating stack | |
3796 | frames in @value{GDBN} commands. | |
3797 | ||
6d2ebf8b SS |
3798 | @c The -fomit-frame-pointer below perennially causes hbox overflow |
3799 | @c underflow problems. | |
c906108c SS |
3800 | @cindex frameless execution |
3801 | Some compilers provide a way to compile functions so that they operate | |
6d2ebf8b SS |
3802 | without stack frames. (For example, the @value{GCC} option |
3803 | @example | |
3804 | @samp{-fomit-frame-pointer} | |
3805 | @end example | |
3806 | generates functions without a frame.) | |
c906108c SS |
3807 | This is occasionally done with heavily used library functions to save |
3808 | the frame setup time. @value{GDBN} has limited facilities for dealing | |
3809 | with these function invocations. If the innermost function invocation | |
3810 | has no stack frame, @value{GDBN} nevertheless regards it as though | |
3811 | it had a separate frame, which is numbered zero as usual, allowing | |
3812 | correct tracing of the function call chain. However, @value{GDBN} has | |
3813 | no provision for frameless functions elsewhere in the stack. | |
3814 | ||
3815 | @table @code | |
d4f3574e | 3816 | @kindex frame@r{, command} |
41afff9a | 3817 | @cindex current stack frame |
c906108c | 3818 | @item frame @var{args} |
5d161b24 | 3819 | The @code{frame} command allows you to move from one stack frame to another, |
c906108c | 3820 | and to print the stack frame you select. @var{args} may be either the |
5d161b24 DB |
3821 | address of the frame or the stack frame number. Without an argument, |
3822 | @code{frame} prints the current stack frame. | |
c906108c SS |
3823 | |
3824 | @kindex select-frame | |
41afff9a | 3825 | @cindex selecting frame silently |
c906108c SS |
3826 | @item select-frame |
3827 | The @code{select-frame} command allows you to move from one stack frame | |
3828 | to another without printing the frame. This is the silent version of | |
3829 | @code{frame}. | |
3830 | @end table | |
3831 | ||
6d2ebf8b | 3832 | @node Backtrace |
c906108c SS |
3833 | @section Backtraces |
3834 | ||
3835 | @cindex backtraces | |
3836 | @cindex tracebacks | |
3837 | @cindex stack traces | |
3838 | A backtrace is a summary of how your program got where it is. It shows one | |
3839 | line per frame, for many frames, starting with the currently executing | |
3840 | frame (frame zero), followed by its caller (frame one), and on up the | |
3841 | stack. | |
3842 | ||
3843 | @table @code | |
3844 | @kindex backtrace | |
41afff9a | 3845 | @kindex bt @r{(@code{backtrace})} |
c906108c SS |
3846 | @item backtrace |
3847 | @itemx bt | |
3848 | Print a backtrace of the entire stack: one line per frame for all | |
3849 | frames in the stack. | |
3850 | ||
3851 | You can stop the backtrace at any time by typing the system interrupt | |
3852 | character, normally @kbd{C-c}. | |
3853 | ||
3854 | @item backtrace @var{n} | |
3855 | @itemx bt @var{n} | |
3856 | Similar, but print only the innermost @var{n} frames. | |
3857 | ||
3858 | @item backtrace -@var{n} | |
3859 | @itemx bt -@var{n} | |
3860 | Similar, but print only the outermost @var{n} frames. | |
3861 | @end table | |
3862 | ||
3863 | @kindex where | |
3864 | @kindex info stack | |
41afff9a | 3865 | @kindex info s @r{(@code{info stack})} |
c906108c SS |
3866 | The names @code{where} and @code{info stack} (abbreviated @code{info s}) |
3867 | are additional aliases for @code{backtrace}. | |
3868 | ||
3869 | Each line in the backtrace shows the frame number and the function name. | |
3870 | The program counter value is also shown---unless you use @code{set | |
3871 | print address off}. The backtrace also shows the source file name and | |
3872 | line number, as well as the arguments to the function. The program | |
3873 | counter value is omitted if it is at the beginning of the code for that | |
3874 | line number. | |
3875 | ||
3876 | Here is an example of a backtrace. It was made with the command | |
3877 | @samp{bt 3}, so it shows the innermost three frames. | |
3878 | ||
3879 | @smallexample | |
3880 | @group | |
5d161b24 | 3881 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) |
c906108c SS |
3882 | at builtin.c:993 |
3883 | #1 0x6e38 in expand_macro (sym=0x2b600) at macro.c:242 | |
3884 | #2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08) | |
3885 | at macro.c:71 | |
3886 | (More stack frames follow...) | |
3887 | @end group | |
3888 | @end smallexample | |
3889 | ||
3890 | @noindent | |
3891 | The display for frame zero does not begin with a program counter | |
3892 | value, indicating that your program has stopped at the beginning of the | |
3893 | code for line @code{993} of @code{builtin.c}. | |
3894 | ||
6d2ebf8b | 3895 | @node Selection |
c906108c SS |
3896 | @section Selecting a frame |
3897 | ||
3898 | Most commands for examining the stack and other data in your program work on | |
3899 | whichever stack frame is selected at the moment. Here are the commands for | |
3900 | selecting a stack frame; all of them finish by printing a brief description | |
3901 | of the stack frame just selected. | |
3902 | ||
3903 | @table @code | |
d4f3574e | 3904 | @kindex frame@r{, selecting} |
41afff9a | 3905 | @kindex f @r{(@code{frame})} |
c906108c SS |
3906 | @item frame @var{n} |
3907 | @itemx f @var{n} | |
3908 | Select frame number @var{n}. Recall that frame zero is the innermost | |
3909 | (currently executing) frame, frame one is the frame that called the | |
3910 | innermost one, and so on. The highest-numbered frame is the one for | |
3911 | @code{main}. | |
3912 | ||
3913 | @item frame @var{addr} | |
3914 | @itemx f @var{addr} | |
3915 | Select the frame at address @var{addr}. This is useful mainly if the | |
3916 | chaining of stack frames has been damaged by a bug, making it | |
3917 | impossible for @value{GDBN} to assign numbers properly to all frames. In | |
3918 | addition, this can be useful when your program has multiple stacks and | |
3919 | switches between them. | |
3920 | ||
c906108c SS |
3921 | On the SPARC architecture, @code{frame} needs two addresses to |
3922 | select an arbitrary frame: a frame pointer and a stack pointer. | |
3923 | ||
3924 | On the MIPS and Alpha architecture, it needs two addresses: a stack | |
3925 | pointer and a program counter. | |
3926 | ||
3927 | On the 29k architecture, it needs three addresses: a register stack | |
3928 | pointer, a program counter, and a memory stack pointer. | |
3929 | @c note to future updaters: this is conditioned on a flag | |
3930 | @c SETUP_ARBITRARY_FRAME in the tm-*.h files. The above is up to date | |
3931 | @c as of 27 Jan 1994. | |
c906108c SS |
3932 | |
3933 | @kindex up | |
3934 | @item up @var{n} | |
3935 | Move @var{n} frames up the stack. For positive numbers @var{n}, this | |
3936 | advances toward the outermost frame, to higher frame numbers, to frames | |
3937 | that have existed longer. @var{n} defaults to one. | |
3938 | ||
3939 | @kindex down | |
41afff9a | 3940 | @kindex do @r{(@code{down})} |
c906108c SS |
3941 | @item down @var{n} |
3942 | Move @var{n} frames down the stack. For positive numbers @var{n}, this | |
3943 | advances toward the innermost frame, to lower frame numbers, to frames | |
3944 | that were created more recently. @var{n} defaults to one. You may | |
3945 | abbreviate @code{down} as @code{do}. | |
3946 | @end table | |
3947 | ||
3948 | All of these commands end by printing two lines of output describing the | |
3949 | frame. The first line shows the frame number, the function name, the | |
3950 | arguments, and the source file and line number of execution in that | |
5d161b24 | 3951 | frame. The second line shows the text of that source line. |
c906108c SS |
3952 | |
3953 | @need 1000 | |
3954 | For example: | |
3955 | ||
3956 | @smallexample | |
3957 | @group | |
3958 | (@value{GDBP}) up | |
3959 | #1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc) | |
3960 | at env.c:10 | |
3961 | 10 read_input_file (argv[i]); | |
3962 | @end group | |
3963 | @end smallexample | |
3964 | ||
3965 | After such a printout, the @code{list} command with no arguments | |
3966 | prints ten lines centered on the point of execution in the frame. | |
3967 | @xref{List, ,Printing source lines}. | |
3968 | ||
3969 | @table @code | |
3970 | @kindex down-silently | |
3971 | @kindex up-silently | |
3972 | @item up-silently @var{n} | |
3973 | @itemx down-silently @var{n} | |
3974 | These two commands are variants of @code{up} and @code{down}, | |
3975 | respectively; they differ in that they do their work silently, without | |
3976 | causing display of the new frame. They are intended primarily for use | |
3977 | in @value{GDBN} command scripts, where the output might be unnecessary and | |
3978 | distracting. | |
3979 | @end table | |
3980 | ||
6d2ebf8b | 3981 | @node Frame Info |
c906108c SS |
3982 | @section Information about a frame |
3983 | ||
3984 | There are several other commands to print information about the selected | |
3985 | stack frame. | |
3986 | ||
3987 | @table @code | |
3988 | @item frame | |
3989 | @itemx f | |
3990 | When used without any argument, this command does not change which | |
3991 | frame is selected, but prints a brief description of the currently | |
3992 | selected stack frame. It can be abbreviated @code{f}. With an | |
3993 | argument, this command is used to select a stack frame. | |
3994 | @xref{Selection, ,Selecting a frame}. | |
3995 | ||
3996 | @kindex info frame | |
41afff9a | 3997 | @kindex info f @r{(@code{info frame})} |
c906108c SS |
3998 | @item info frame |
3999 | @itemx info f | |
4000 | This command prints a verbose description of the selected stack frame, | |
4001 | including: | |
4002 | ||
4003 | @itemize @bullet | |
5d161b24 DB |
4004 | @item |
4005 | the address of the frame | |
c906108c SS |
4006 | @item |
4007 | the address of the next frame down (called by this frame) | |
4008 | @item | |
4009 | the address of the next frame up (caller of this frame) | |
4010 | @item | |
4011 | the language in which the source code corresponding to this frame is written | |
4012 | @item | |
4013 | the address of the frame's arguments | |
4014 | @item | |
d4f3574e SS |
4015 | the address of the frame's local variables |
4016 | @item | |
c906108c SS |
4017 | the program counter saved in it (the address of execution in the caller frame) |
4018 | @item | |
4019 | which registers were saved in the frame | |
4020 | @end itemize | |
4021 | ||
4022 | @noindent The verbose description is useful when | |
4023 | something has gone wrong that has made the stack format fail to fit | |
4024 | the usual conventions. | |
4025 | ||
4026 | @item info frame @var{addr} | |
4027 | @itemx info f @var{addr} | |
4028 | Print a verbose description of the frame at address @var{addr}, without | |
4029 | selecting that frame. The selected frame remains unchanged by this | |
4030 | command. This requires the same kind of address (more than one for some | |
4031 | architectures) that you specify in the @code{frame} command. | |
4032 | @xref{Selection, ,Selecting a frame}. | |
4033 | ||
4034 | @kindex info args | |
4035 | @item info args | |
4036 | Print the arguments of the selected frame, each on a separate line. | |
4037 | ||
4038 | @item info locals | |
4039 | @kindex info locals | |
4040 | Print the local variables of the selected frame, each on a separate | |
4041 | line. These are all variables (declared either static or automatic) | |
4042 | accessible at the point of execution of the selected frame. | |
4043 | ||
c906108c | 4044 | @kindex info catch |
d4f3574e SS |
4045 | @cindex catch exceptions, list active handlers |
4046 | @cindex exception handlers, how to list | |
c906108c SS |
4047 | @item info catch |
4048 | Print a list of all the exception handlers that are active in the | |
4049 | current stack frame at the current point of execution. To see other | |
4050 | exception handlers, visit the associated frame (using the @code{up}, | |
4051 | @code{down}, or @code{frame} commands); then type @code{info catch}. | |
4052 | @xref{Set Catchpoints, , Setting catchpoints}. | |
53a5351d | 4053 | |
c906108c SS |
4054 | @end table |
4055 | ||
c906108c | 4056 | |
6d2ebf8b | 4057 | @node Source |
c906108c SS |
4058 | @chapter Examining Source Files |
4059 | ||
4060 | @value{GDBN} can print parts of your program's source, since the debugging | |
4061 | information recorded in the program tells @value{GDBN} what source files were | |
4062 | used to build it. When your program stops, @value{GDBN} spontaneously prints | |
4063 | the line where it stopped. Likewise, when you select a stack frame | |
4064 | (@pxref{Selection, ,Selecting a frame}), @value{GDBN} prints the line where | |
4065 | execution in that frame has stopped. You can print other portions of | |
4066 | source files by explicit command. | |
4067 | ||
7a292a7a | 4068 | If you use @value{GDBN} through its @sc{gnu} Emacs interface, you may |
d4f3574e | 4069 | prefer to use Emacs facilities to view source; see @ref{Emacs, ,Using |
7a292a7a | 4070 | @value{GDBN} under @sc{gnu} Emacs}. |
c906108c SS |
4071 | |
4072 | @menu | |
4073 | * List:: Printing source lines | |
c906108c | 4074 | * Search:: Searching source files |
c906108c SS |
4075 | * Source Path:: Specifying source directories |
4076 | * Machine Code:: Source and machine code | |
4077 | @end menu | |
4078 | ||
6d2ebf8b | 4079 | @node List |
c906108c SS |
4080 | @section Printing source lines |
4081 | ||
4082 | @kindex list | |
41afff9a | 4083 | @kindex l @r{(@code{list})} |
c906108c | 4084 | To print lines from a source file, use the @code{list} command |
5d161b24 | 4085 | (abbreviated @code{l}). By default, ten lines are printed. |
c906108c SS |
4086 | There are several ways to specify what part of the file you want to print. |
4087 | ||
4088 | Here are the forms of the @code{list} command most commonly used: | |
4089 | ||
4090 | @table @code | |
4091 | @item list @var{linenum} | |
4092 | Print lines centered around line number @var{linenum} in the | |
4093 | current source file. | |
4094 | ||
4095 | @item list @var{function} | |
4096 | Print lines centered around the beginning of function | |
4097 | @var{function}. | |
4098 | ||
4099 | @item list | |
4100 | Print more lines. If the last lines printed were printed with a | |
4101 | @code{list} command, this prints lines following the last lines | |
4102 | printed; however, if the last line printed was a solitary line printed | |
4103 | as part of displaying a stack frame (@pxref{Stack, ,Examining the | |
4104 | Stack}), this prints lines centered around that line. | |
4105 | ||
4106 | @item list - | |
4107 | Print lines just before the lines last printed. | |
4108 | @end table | |
4109 | ||
4110 | By default, @value{GDBN} prints ten source lines with any of these forms of | |
4111 | the @code{list} command. You can change this using @code{set listsize}: | |
4112 | ||
4113 | @table @code | |
4114 | @kindex set listsize | |
4115 | @item set listsize @var{count} | |
4116 | Make the @code{list} command display @var{count} source lines (unless | |
4117 | the @code{list} argument explicitly specifies some other number). | |
4118 | ||
4119 | @kindex show listsize | |
4120 | @item show listsize | |
4121 | Display the number of lines that @code{list} prints. | |
4122 | @end table | |
4123 | ||
4124 | Repeating a @code{list} command with @key{RET} discards the argument, | |
4125 | so it is equivalent to typing just @code{list}. This is more useful | |
4126 | than listing the same lines again. An exception is made for an | |
4127 | argument of @samp{-}; that argument is preserved in repetition so that | |
4128 | each repetition moves up in the source file. | |
4129 | ||
4130 | @cindex linespec | |
4131 | In general, the @code{list} command expects you to supply zero, one or two | |
4132 | @dfn{linespecs}. Linespecs specify source lines; there are several ways | |
d4f3574e | 4133 | of writing them, but the effect is always to specify some source line. |
c906108c SS |
4134 | Here is a complete description of the possible arguments for @code{list}: |
4135 | ||
4136 | @table @code | |
4137 | @item list @var{linespec} | |
4138 | Print lines centered around the line specified by @var{linespec}. | |
4139 | ||
4140 | @item list @var{first},@var{last} | |
4141 | Print lines from @var{first} to @var{last}. Both arguments are | |
4142 | linespecs. | |
4143 | ||
4144 | @item list ,@var{last} | |
4145 | Print lines ending with @var{last}. | |
4146 | ||
4147 | @item list @var{first}, | |
4148 | Print lines starting with @var{first}. | |
4149 | ||
4150 | @item list + | |
4151 | Print lines just after the lines last printed. | |
4152 | ||
4153 | @item list - | |
4154 | Print lines just before the lines last printed. | |
4155 | ||
4156 | @item list | |
4157 | As described in the preceding table. | |
4158 | @end table | |
4159 | ||
4160 | Here are the ways of specifying a single source line---all the | |
4161 | kinds of linespec. | |
4162 | ||
4163 | @table @code | |
4164 | @item @var{number} | |
4165 | Specifies line @var{number} of the current source file. | |
4166 | When a @code{list} command has two linespecs, this refers to | |
4167 | the same source file as the first linespec. | |
4168 | ||
4169 | @item +@var{offset} | |
4170 | Specifies the line @var{offset} lines after the last line printed. | |
4171 | When used as the second linespec in a @code{list} command that has | |
4172 | two, this specifies the line @var{offset} lines down from the | |
4173 | first linespec. | |
4174 | ||
4175 | @item -@var{offset} | |
4176 | Specifies the line @var{offset} lines before the last line printed. | |
4177 | ||
4178 | @item @var{filename}:@var{number} | |
4179 | Specifies line @var{number} in the source file @var{filename}. | |
4180 | ||
4181 | @item @var{function} | |
4182 | Specifies the line that begins the body of the function @var{function}. | |
4183 | For example: in C, this is the line with the open brace. | |
4184 | ||
4185 | @item @var{filename}:@var{function} | |
4186 | Specifies the line of the open-brace that begins the body of the | |
4187 | function @var{function} in the file @var{filename}. You only need the | |
4188 | file name with a function name to avoid ambiguity when there are | |
4189 | identically named functions in different source files. | |
4190 | ||
4191 | @item *@var{address} | |
4192 | Specifies the line containing the program address @var{address}. | |
4193 | @var{address} may be any expression. | |
4194 | @end table | |
4195 | ||
6d2ebf8b | 4196 | @node Search |
c906108c SS |
4197 | @section Searching source files |
4198 | @cindex searching | |
4199 | @kindex reverse-search | |
4200 | ||
4201 | There are two commands for searching through the current source file for a | |
4202 | regular expression. | |
4203 | ||
4204 | @table @code | |
4205 | @kindex search | |
4206 | @kindex forward-search | |
4207 | @item forward-search @var{regexp} | |
4208 | @itemx search @var{regexp} | |
4209 | The command @samp{forward-search @var{regexp}} checks each line, | |
4210 | starting with the one following the last line listed, for a match for | |
5d161b24 | 4211 | @var{regexp}. It lists the line that is found. You can use the |
c906108c SS |
4212 | synonym @samp{search @var{regexp}} or abbreviate the command name as |
4213 | @code{fo}. | |
4214 | ||
4215 | @item reverse-search @var{regexp} | |
4216 | The command @samp{reverse-search @var{regexp}} checks each line, starting | |
4217 | with the one before the last line listed and going backward, for a match | |
4218 | for @var{regexp}. It lists the line that is found. You can abbreviate | |
4219 | this command as @code{rev}. | |
4220 | @end table | |
c906108c | 4221 | |
6d2ebf8b | 4222 | @node Source Path |
c906108c SS |
4223 | @section Specifying source directories |
4224 | ||
4225 | @cindex source path | |
4226 | @cindex directories for source files | |
4227 | Executable programs sometimes do not record the directories of the source | |
4228 | files from which they were compiled, just the names. Even when they do, | |
4229 | the directories could be moved between the compilation and your debugging | |
4230 | session. @value{GDBN} has a list of directories to search for source files; | |
4231 | this is called the @dfn{source path}. Each time @value{GDBN} wants a source file, | |
4232 | it tries all the directories in the list, in the order they are present | |
4233 | in the list, until it finds a file with the desired name. Note that | |
4234 | the executable search path is @emph{not} used for this purpose. Neither is | |
4235 | the current working directory, unless it happens to be in the source | |
4236 | path. | |
4237 | ||
4238 | If @value{GDBN} cannot find a source file in the source path, and the | |
4239 | object program records a directory, @value{GDBN} tries that directory | |
4240 | too. If the source path is empty, and there is no record of the | |
4241 | compilation directory, @value{GDBN} looks in the current directory as a | |
4242 | last resort. | |
4243 | ||
4244 | Whenever you reset or rearrange the source path, @value{GDBN} clears out | |
4245 | any information it has cached about where source files are found and where | |
4246 | each line is in the file. | |
4247 | ||
4248 | @kindex directory | |
4249 | @kindex dir | |
d4f3574e SS |
4250 | When you start @value{GDBN}, its source path includes only @samp{cdir} |
4251 | and @samp{cwd}, in that order. | |
c906108c SS |
4252 | To add other directories, use the @code{directory} command. |
4253 | ||
4254 | @table @code | |
4255 | @item directory @var{dirname} @dots{} | |
4256 | @item dir @var{dirname} @dots{} | |
4257 | Add directory @var{dirname} to the front of the source path. Several | |
d4f3574e SS |
4258 | directory names may be given to this command, separated by @samp{:} |
4259 | (@samp{;} on MS-DOS and MS-Windows, where @samp{:} usually appears as | |
4260 | part of absolute file names) or | |
c906108c SS |
4261 | whitespace. You may specify a directory that is already in the source |
4262 | path; this moves it forward, so @value{GDBN} searches it sooner. | |
4263 | ||
4264 | @kindex cdir | |
4265 | @kindex cwd | |
41afff9a EZ |
4266 | @vindex $cdir@r{, convenience variable} |
4267 | @vindex $cwdr@r{, convenience variable} | |
c906108c SS |
4268 | @cindex compilation directory |
4269 | @cindex current directory | |
4270 | @cindex working directory | |
4271 | @cindex directory, current | |
4272 | @cindex directory, compilation | |
4273 | You can use the string @samp{$cdir} to refer to the compilation | |
4274 | directory (if one is recorded), and @samp{$cwd} to refer to the current | |
4275 | working directory. @samp{$cwd} is not the same as @samp{.}---the former | |
4276 | tracks the current working directory as it changes during your @value{GDBN} | |
4277 | session, while the latter is immediately expanded to the current | |
4278 | directory at the time you add an entry to the source path. | |
4279 | ||
4280 | @item directory | |
4281 | Reset the source path to empty again. This requires confirmation. | |
4282 | ||
4283 | @c RET-repeat for @code{directory} is explicitly disabled, but since | |
4284 | @c repeating it would be a no-op we do not say that. (thanks to RMS) | |
4285 | ||
4286 | @item show directories | |
4287 | @kindex show directories | |
4288 | Print the source path: show which directories it contains. | |
4289 | @end table | |
4290 | ||
4291 | If your source path is cluttered with directories that are no longer of | |
4292 | interest, @value{GDBN} may sometimes cause confusion by finding the wrong | |
4293 | versions of source. You can correct the situation as follows: | |
4294 | ||
4295 | @enumerate | |
4296 | @item | |
4297 | Use @code{directory} with no argument to reset the source path to empty. | |
4298 | ||
4299 | @item | |
4300 | Use @code{directory} with suitable arguments to reinstall the | |
4301 | directories you want in the source path. You can add all the | |
4302 | directories in one command. | |
4303 | @end enumerate | |
4304 | ||
6d2ebf8b | 4305 | @node Machine Code |
c906108c SS |
4306 | @section Source and machine code |
4307 | ||
4308 | You can use the command @code{info line} to map source lines to program | |
4309 | addresses (and vice versa), and the command @code{disassemble} to display | |
4310 | a range of addresses as machine instructions. When run under @sc{gnu} Emacs | |
d4f3574e | 4311 | mode, the @code{info line} command causes the arrow to point to the |
5d161b24 | 4312 | line specified. Also, @code{info line} prints addresses in symbolic form as |
c906108c SS |
4313 | well as hex. |
4314 | ||
4315 | @table @code | |
4316 | @kindex info line | |
4317 | @item info line @var{linespec} | |
4318 | Print the starting and ending addresses of the compiled code for | |
4319 | source line @var{linespec}. You can specify source lines in any of | |
4320 | the ways understood by the @code{list} command (@pxref{List, ,Printing | |
4321 | source lines}). | |
4322 | @end table | |
4323 | ||
4324 | For example, we can use @code{info line} to discover the location of | |
4325 | the object code for the first line of function | |
4326 | @code{m4_changequote}: | |
4327 | ||
d4f3574e SS |
4328 | @c FIXME: I think this example should also show the addresses in |
4329 | @c symbolic form, as they usually would be displayed. | |
c906108c | 4330 | @smallexample |
96a2c332 | 4331 | (@value{GDBP}) info line m4_changequote |
c906108c SS |
4332 | Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350. |
4333 | @end smallexample | |
4334 | ||
4335 | @noindent | |
4336 | We can also inquire (using @code{*@var{addr}} as the form for | |
4337 | @var{linespec}) what source line covers a particular address: | |
4338 | @smallexample | |
4339 | (@value{GDBP}) info line *0x63ff | |
4340 | Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404. | |
4341 | @end smallexample | |
4342 | ||
4343 | @cindex @code{$_} and @code{info line} | |
41afff9a | 4344 | @kindex x@r{(examine), and} info line |
c906108c SS |
4345 | After @code{info line}, the default address for the @code{x} command |
4346 | is changed to the starting address of the line, so that @samp{x/i} is | |
4347 | sufficient to begin examining the machine code (@pxref{Memory, | |
4348 | ,Examining memory}). Also, this address is saved as the value of the | |
4349 | convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience | |
4350 | variables}). | |
4351 | ||
4352 | @table @code | |
4353 | @kindex disassemble | |
4354 | @cindex assembly instructions | |
4355 | @cindex instructions, assembly | |
4356 | @cindex machine instructions | |
4357 | @cindex listing machine instructions | |
4358 | @item disassemble | |
4359 | This specialized command dumps a range of memory as machine | |
4360 | instructions. The default memory range is the function surrounding the | |
4361 | program counter of the selected frame. A single argument to this | |
4362 | command is a program counter value; @value{GDBN} dumps the function | |
4363 | surrounding this value. Two arguments specify a range of addresses | |
4364 | (first inclusive, second exclusive) to dump. | |
4365 | @end table | |
4366 | ||
c906108c SS |
4367 | The following example shows the disassembly of a range of addresses of |
4368 | HP PA-RISC 2.0 code: | |
4369 | ||
4370 | @smallexample | |
4371 | (@value{GDBP}) disas 0x32c4 0x32e4 | |
4372 | Dump of assembler code from 0x32c4 to 0x32e4: | |
4373 | 0x32c4 <main+204>: addil 0,dp | |
4374 | 0x32c8 <main+208>: ldw 0x22c(sr0,r1),r26 | |
4375 | 0x32cc <main+212>: ldil 0x3000,r31 | |
4376 | 0x32d0 <main+216>: ble 0x3f8(sr4,r31) | |
4377 | 0x32d4 <main+220>: ldo 0(r31),rp | |
4378 | 0x32d8 <main+224>: addil -0x800,dp | |
4379 | 0x32dc <main+228>: ldo 0x588(r1),r26 | |
4380 | 0x32e0 <main+232>: ldil 0x3000,r31 | |
4381 | End of assembler dump. | |
4382 | @end smallexample | |
c906108c SS |
4383 | |
4384 | Some architectures have more than one commonly-used set of instruction | |
4385 | mnemonics or other syntax. | |
4386 | ||
4387 | @table @code | |
d4f3574e | 4388 | @kindex set disassembly-flavor |
c906108c SS |
4389 | @cindex assembly instructions |
4390 | @cindex instructions, assembly | |
4391 | @cindex machine instructions | |
4392 | @cindex listing machine instructions | |
d4f3574e SS |
4393 | @cindex Intel disassembly flavor |
4394 | @cindex AT&T disassembly flavor | |
4395 | @item set disassembly-flavor @var{instruction-set} | |
c906108c SS |
4396 | Select the instruction set to use when disassembling the |
4397 | program via the @code{disassemble} or @code{x/i} commands. | |
4398 | ||
4399 | Currently this command is only defined for the Intel x86 family. You | |
d4f3574e SS |
4400 | can set @var{instruction-set} to either @code{intel} or @code{att}. |
4401 | The default is @code{att}, the AT&T flavor used by default by Unix | |
4402 | assemblers for x86-based targets. | |
c906108c SS |
4403 | @end table |
4404 | ||
4405 | ||
6d2ebf8b | 4406 | @node Data |
c906108c SS |
4407 | @chapter Examining Data |
4408 | ||
4409 | @cindex printing data | |
4410 | @cindex examining data | |
4411 | @kindex print | |
4412 | @kindex inspect | |
4413 | @c "inspect" is not quite a synonym if you are using Epoch, which we do not | |
4414 | @c document because it is nonstandard... Under Epoch it displays in a | |
4415 | @c different window or something like that. | |
4416 | The usual way to examine data in your program is with the @code{print} | |
7a292a7a SS |
4417 | command (abbreviated @code{p}), or its synonym @code{inspect}. It |
4418 | evaluates and prints the value of an expression of the language your | |
4419 | program is written in (@pxref{Languages, ,Using @value{GDBN} with | |
4420 | Different Languages}). | |
c906108c SS |
4421 | |
4422 | @table @code | |
d4f3574e SS |
4423 | @item print @var{expr} |
4424 | @itemx print /@var{f} @var{expr} | |
4425 | @var{expr} is an expression (in the source language). By default the | |
4426 | value of @var{expr} is printed in a format appropriate to its data type; | |
c906108c | 4427 | you can choose a different format by specifying @samp{/@var{f}}, where |
d4f3574e | 4428 | @var{f} is a letter specifying the format; see @ref{Output Formats,,Output |
c906108c SS |
4429 | formats}. |
4430 | ||
4431 | @item print | |
4432 | @itemx print /@var{f} | |
d4f3574e | 4433 | If you omit @var{expr}, @value{GDBN} displays the last value again (from the |
c906108c SS |
4434 | @dfn{value history}; @pxref{Value History, ,Value history}). This allows you to |
4435 | conveniently inspect the same value in an alternative format. | |
4436 | @end table | |
4437 | ||
4438 | A more low-level way of examining data is with the @code{x} command. | |
4439 | It examines data in memory at a specified address and prints it in a | |
4440 | specified format. @xref{Memory, ,Examining memory}. | |
4441 | ||
7a292a7a | 4442 | If you are interested in information about types, or about how the |
d4f3574e SS |
4443 | fields of a struct or a class are declared, use the @code{ptype @var{exp}} |
4444 | command rather than @code{print}. @xref{Symbols, ,Examining the Symbol | |
7a292a7a | 4445 | Table}. |
c906108c SS |
4446 | |
4447 | @menu | |
4448 | * Expressions:: Expressions | |
4449 | * Variables:: Program variables | |
4450 | * Arrays:: Artificial arrays | |
4451 | * Output Formats:: Output formats | |
4452 | * Memory:: Examining memory | |
4453 | * Auto Display:: Automatic display | |
4454 | * Print Settings:: Print settings | |
4455 | * Value History:: Value history | |
4456 | * Convenience Vars:: Convenience variables | |
4457 | * Registers:: Registers | |
c906108c | 4458 | * Floating Point Hardware:: Floating point hardware |
29e57380 | 4459 | * Memory Region Attributes:: Memory region attributes |
c906108c SS |
4460 | @end menu |
4461 | ||
6d2ebf8b | 4462 | @node Expressions |
c906108c SS |
4463 | @section Expressions |
4464 | ||
4465 | @cindex expressions | |
4466 | @code{print} and many other @value{GDBN} commands accept an expression and | |
4467 | compute its value. Any kind of constant, variable or operator defined | |
4468 | by the programming language you are using is valid in an expression in | |
4469 | @value{GDBN}. This includes conditional expressions, function calls, casts | |
4470 | and string constants. It unfortunately does not include symbols defined | |
4471 | by preprocessor @code{#define} commands. | |
4472 | ||
d4f3574e SS |
4473 | @value{GDBN} supports array constants in expressions input by |
4474 | the user. The syntax is @{@var{element}, @var{element}@dots{}@}. For example, | |
5d161b24 | 4475 | you can use the command @code{print @{1, 2, 3@}} to build up an array in |
d4f3574e | 4476 | memory that is @code{malloc}ed in the target program. |
c906108c | 4477 | |
c906108c SS |
4478 | Because C is so widespread, most of the expressions shown in examples in |
4479 | this manual are in C. @xref{Languages, , Using @value{GDBN} with Different | |
4480 | Languages}, for information on how to use expressions in other | |
4481 | languages. | |
4482 | ||
4483 | In this section, we discuss operators that you can use in @value{GDBN} | |
4484 | expressions regardless of your programming language. | |
4485 | ||
4486 | Casts are supported in all languages, not just in C, because it is so | |
4487 | useful to cast a number into a pointer in order to examine a structure | |
4488 | at that address in memory. | |
4489 | @c FIXME: casts supported---Mod2 true? | |
c906108c SS |
4490 | |
4491 | @value{GDBN} supports these operators, in addition to those common | |
4492 | to programming languages: | |
4493 | ||
4494 | @table @code | |
4495 | @item @@ | |
4496 | @samp{@@} is a binary operator for treating parts of memory as arrays. | |
4497 | @xref{Arrays, ,Artificial arrays}, for more information. | |
4498 | ||
4499 | @item :: | |
4500 | @samp{::} allows you to specify a variable in terms of the file or | |
4501 | function where it is defined. @xref{Variables, ,Program variables}. | |
4502 | ||
4503 | @cindex @{@var{type}@} | |
4504 | @cindex type casting memory | |
4505 | @cindex memory, viewing as typed object | |
4506 | @cindex casts, to view memory | |
4507 | @item @{@var{type}@} @var{addr} | |
4508 | Refers to an object of type @var{type} stored at address @var{addr} in | |
4509 | memory. @var{addr} may be any expression whose value is an integer or | |
4510 | pointer (but parentheses are required around binary operators, just as in | |
4511 | a cast). This construct is allowed regardless of what kind of data is | |
4512 | normally supposed to reside at @var{addr}. | |
4513 | @end table | |
4514 | ||
6d2ebf8b | 4515 | @node Variables |
c906108c SS |
4516 | @section Program variables |
4517 | ||
4518 | The most common kind of expression to use is the name of a variable | |
4519 | in your program. | |
4520 | ||
4521 | Variables in expressions are understood in the selected stack frame | |
4522 | (@pxref{Selection, ,Selecting a frame}); they must be either: | |
4523 | ||
4524 | @itemize @bullet | |
4525 | @item | |
4526 | global (or file-static) | |
4527 | @end itemize | |
4528 | ||
5d161b24 | 4529 | @noindent or |
c906108c SS |
4530 | |
4531 | @itemize @bullet | |
4532 | @item | |
4533 | visible according to the scope rules of the | |
4534 | programming language from the point of execution in that frame | |
5d161b24 | 4535 | @end itemize |
c906108c SS |
4536 | |
4537 | @noindent This means that in the function | |
4538 | ||
4539 | @example | |
4540 | foo (a) | |
4541 | int a; | |
4542 | @{ | |
4543 | bar (a); | |
4544 | @{ | |
4545 | int b = test (); | |
4546 | bar (b); | |
4547 | @} | |
4548 | @} | |
4549 | @end example | |
4550 | ||
4551 | @noindent | |
4552 | you can examine and use the variable @code{a} whenever your program is | |
4553 | executing within the function @code{foo}, but you can only use or | |
4554 | examine the variable @code{b} while your program is executing inside | |
4555 | the block where @code{b} is declared. | |
4556 | ||
4557 | @cindex variable name conflict | |
4558 | There is an exception: you can refer to a variable or function whose | |
4559 | scope is a single source file even if the current execution point is not | |
4560 | in this file. But it is possible to have more than one such variable or | |
4561 | function with the same name (in different source files). If that | |
4562 | happens, referring to that name has unpredictable effects. If you wish, | |
4563 | you can specify a static variable in a particular function or file, | |
4564 | using the colon-colon notation: | |
4565 | ||
d4f3574e | 4566 | @cindex colon-colon, context for variables/functions |
c906108c SS |
4567 | @iftex |
4568 | @c info cannot cope with a :: index entry, but why deprive hard copy readers? | |
41afff9a | 4569 | @cindex @code{::}, context for variables/functions |
c906108c SS |
4570 | @end iftex |
4571 | @example | |
4572 | @var{file}::@var{variable} | |
4573 | @var{function}::@var{variable} | |
4574 | @end example | |
4575 | ||
4576 | @noindent | |
4577 | Here @var{file} or @var{function} is the name of the context for the | |
4578 | static @var{variable}. In the case of file names, you can use quotes to | |
4579 | make sure @value{GDBN} parses the file name as a single word---for example, | |
4580 | to print a global value of @code{x} defined in @file{f2.c}: | |
4581 | ||
4582 | @example | |
4583 | (@value{GDBP}) p 'f2.c'::x | |
4584 | @end example | |
4585 | ||
b37052ae | 4586 | @cindex C@t{++} scope resolution |
c906108c | 4587 | This use of @samp{::} is very rarely in conflict with the very similar |
b37052ae | 4588 | use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++} |
c906108c SS |
4589 | scope resolution operator in @value{GDBN} expressions. |
4590 | @c FIXME: Um, so what happens in one of those rare cases where it's in | |
4591 | @c conflict?? --mew | |
c906108c SS |
4592 | |
4593 | @cindex wrong values | |
4594 | @cindex variable values, wrong | |
4595 | @quotation | |
4596 | @emph{Warning:} Occasionally, a local variable may appear to have the | |
4597 | wrong value at certain points in a function---just after entry to a new | |
4598 | scope, and just before exit. | |
4599 | @end quotation | |
4600 | You may see this problem when you are stepping by machine instructions. | |
4601 | This is because, on most machines, it takes more than one instruction to | |
4602 | set up a stack frame (including local variable definitions); if you are | |
4603 | stepping by machine instructions, variables may appear to have the wrong | |
4604 | values until the stack frame is completely built. On exit, it usually | |
4605 | also takes more than one machine instruction to destroy a stack frame; | |
4606 | after you begin stepping through that group of instructions, local | |
4607 | variable definitions may be gone. | |
4608 | ||
4609 | This may also happen when the compiler does significant optimizations. | |
4610 | To be sure of always seeing accurate values, turn off all optimization | |
4611 | when compiling. | |
4612 | ||
d4f3574e SS |
4613 | @cindex ``No symbol "foo" in current context'' |
4614 | Another possible effect of compiler optimizations is to optimize | |
4615 | unused variables out of existence, or assign variables to registers (as | |
4616 | opposed to memory addresses). Depending on the support for such cases | |
4617 | offered by the debug info format used by the compiler, @value{GDBN} | |
4618 | might not be able to display values for such local variables. If that | |
4619 | happens, @value{GDBN} will print a message like this: | |
4620 | ||
4621 | @example | |
4622 | No symbol "foo" in current context. | |
4623 | @end example | |
4624 | ||
4625 | To solve such problems, either recompile without optimizations, or use a | |
4626 | different debug info format, if the compiler supports several such | |
b37052ae | 4627 | formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler usually |
d4f3574e SS |
4628 | supports the @samp{-gstabs} option. @samp{-gstabs} produces debug info |
4629 | in a format that is superior to formats such as COFF. You may be able | |
96c405b3 | 4630 | to use DWARF2 (@samp{-gdwarf-2}), which is also an effective form for |
d4f3574e SS |
4631 | debug info. See @ref{Debugging Options,,Options for Debugging Your |
4632 | Program or @sc{gnu} CC, gcc.info, Using @sc{gnu} CC}, for more | |
4633 | information. | |
4634 | ||
4635 | ||
6d2ebf8b | 4636 | @node Arrays |
c906108c SS |
4637 | @section Artificial arrays |
4638 | ||
4639 | @cindex artificial array | |
41afff9a | 4640 | @kindex @@@r{, referencing memory as an array} |
c906108c SS |
4641 | It is often useful to print out several successive objects of the |
4642 | same type in memory; a section of an array, or an array of | |
4643 | dynamically determined size for which only a pointer exists in the | |
4644 | program. | |
4645 | ||
4646 | You can do this by referring to a contiguous span of memory as an | |
4647 | @dfn{artificial array}, using the binary operator @samp{@@}. The left | |
4648 | operand of @samp{@@} should be the first element of the desired array | |
4649 | and be an individual object. The right operand should be the desired length | |
4650 | of the array. The result is an array value whose elements are all of | |
4651 | the type of the left argument. The first element is actually the left | |
4652 | argument; the second element comes from bytes of memory immediately | |
4653 | following those that hold the first element, and so on. Here is an | |
4654 | example. If a program says | |
4655 | ||
4656 | @example | |
4657 | int *array = (int *) malloc (len * sizeof (int)); | |
4658 | @end example | |
4659 | ||
4660 | @noindent | |
4661 | you can print the contents of @code{array} with | |
4662 | ||
4663 | @example | |
4664 | p *array@@len | |
4665 | @end example | |
4666 | ||
4667 | The left operand of @samp{@@} must reside in memory. Array values made | |
4668 | with @samp{@@} in this way behave just like other arrays in terms of | |
4669 | subscripting, and are coerced to pointers when used in expressions. | |
4670 | Artificial arrays most often appear in expressions via the value history | |
4671 | (@pxref{Value History, ,Value history}), after printing one out. | |
4672 | ||
4673 | Another way to create an artificial array is to use a cast. | |
4674 | This re-interprets a value as if it were an array. | |
4675 | The value need not be in memory: | |
4676 | @example | |
4677 | (@value{GDBP}) p/x (short[2])0x12345678 | |
4678 | $1 = @{0x1234, 0x5678@} | |
4679 | @end example | |
4680 | ||
4681 | As a convenience, if you leave the array length out (as in | |
c3f6f71d | 4682 | @samp{(@var{type}[])@var{value}}) @value{GDBN} calculates the size to fill |
c906108c SS |
4683 | the value (as @samp{sizeof(@var{value})/sizeof(@var{type})}: |
4684 | @example | |
4685 | (@value{GDBP}) p/x (short[])0x12345678 | |
4686 | $2 = @{0x1234, 0x5678@} | |
4687 | @end example | |
4688 | ||
4689 | Sometimes the artificial array mechanism is not quite enough; in | |
4690 | moderately complex data structures, the elements of interest may not | |
4691 | actually be adjacent---for example, if you are interested in the values | |
4692 | of pointers in an array. One useful work-around in this situation is | |
4693 | to use a convenience variable (@pxref{Convenience Vars, ,Convenience | |
4694 | variables}) as a counter in an expression that prints the first | |
4695 | interesting value, and then repeat that expression via @key{RET}. For | |
4696 | instance, suppose you have an array @code{dtab} of pointers to | |
4697 | structures, and you are interested in the values of a field @code{fv} | |
4698 | in each structure. Here is an example of what you might type: | |
4699 | ||
4700 | @example | |
4701 | set $i = 0 | |
4702 | p dtab[$i++]->fv | |
4703 | @key{RET} | |
4704 | @key{RET} | |
4705 | @dots{} | |
4706 | @end example | |
4707 | ||
6d2ebf8b | 4708 | @node Output Formats |
c906108c SS |
4709 | @section Output formats |
4710 | ||
4711 | @cindex formatted output | |
4712 | @cindex output formats | |
4713 | By default, @value{GDBN} prints a value according to its data type. Sometimes | |
4714 | this is not what you want. For example, you might want to print a number | |
4715 | in hex, or a pointer in decimal. Or you might want to view data in memory | |
4716 | at a certain address as a character string or as an instruction. To do | |
4717 | these things, specify an @dfn{output format} when you print a value. | |
4718 | ||
4719 | The simplest use of output formats is to say how to print a value | |
4720 | already computed. This is done by starting the arguments of the | |
4721 | @code{print} command with a slash and a format letter. The format | |
4722 | letters supported are: | |
4723 | ||
4724 | @table @code | |
4725 | @item x | |
4726 | Regard the bits of the value as an integer, and print the integer in | |
4727 | hexadecimal. | |
4728 | ||
4729 | @item d | |
4730 | Print as integer in signed decimal. | |
4731 | ||
4732 | @item u | |
4733 | Print as integer in unsigned decimal. | |
4734 | ||
4735 | @item o | |
4736 | Print as integer in octal. | |
4737 | ||
4738 | @item t | |
4739 | Print as integer in binary. The letter @samp{t} stands for ``two''. | |
4740 | @footnote{@samp{b} cannot be used because these format letters are also | |
4741 | used with the @code{x} command, where @samp{b} stands for ``byte''; | |
d4f3574e | 4742 | see @ref{Memory,,Examining memory}.} |
c906108c SS |
4743 | |
4744 | @item a | |
4745 | @cindex unknown address, locating | |
3d67e040 | 4746 | @cindex locate address |
c906108c SS |
4747 | Print as an address, both absolute in hexadecimal and as an offset from |
4748 | the nearest preceding symbol. You can use this format used to discover | |
4749 | where (in what function) an unknown address is located: | |
4750 | ||
4751 | @example | |
4752 | (@value{GDBP}) p/a 0x54320 | |
4753 | $3 = 0x54320 <_initialize_vx+396> | |
4754 | @end example | |
4755 | ||
3d67e040 EZ |
4756 | @noindent |
4757 | The command @code{info symbol 0x54320} yields similar results. | |
4758 | @xref{Symbols, info symbol}. | |
4759 | ||
c906108c SS |
4760 | @item c |
4761 | Regard as an integer and print it as a character constant. | |
4762 | ||
4763 | @item f | |
4764 | Regard the bits of the value as a floating point number and print | |
4765 | using typical floating point syntax. | |
4766 | @end table | |
4767 | ||
4768 | For example, to print the program counter in hex (@pxref{Registers}), type | |
4769 | ||
4770 | @example | |
4771 | p/x $pc | |
4772 | @end example | |
4773 | ||
4774 | @noindent | |
4775 | Note that no space is required before the slash; this is because command | |
4776 | names in @value{GDBN} cannot contain a slash. | |
4777 | ||
4778 | To reprint the last value in the value history with a different format, | |
4779 | you can use the @code{print} command with just a format and no | |
4780 | expression. For example, @samp{p/x} reprints the last value in hex. | |
4781 | ||
6d2ebf8b | 4782 | @node Memory |
c906108c SS |
4783 | @section Examining memory |
4784 | ||
4785 | You can use the command @code{x} (for ``examine'') to examine memory in | |
4786 | any of several formats, independently of your program's data types. | |
4787 | ||
4788 | @cindex examining memory | |
4789 | @table @code | |
41afff9a | 4790 | @kindex x @r{(examine memory)} |
c906108c SS |
4791 | @item x/@var{nfu} @var{addr} |
4792 | @itemx x @var{addr} | |
4793 | @itemx x | |
4794 | Use the @code{x} command to examine memory. | |
4795 | @end table | |
4796 | ||
4797 | @var{n}, @var{f}, and @var{u} are all optional parameters that specify how | |
4798 | much memory to display and how to format it; @var{addr} is an | |
4799 | expression giving the address where you want to start displaying memory. | |
4800 | If you use defaults for @var{nfu}, you need not type the slash @samp{/}. | |
4801 | Several commands set convenient defaults for @var{addr}. | |
4802 | ||
4803 | @table @r | |
4804 | @item @var{n}, the repeat count | |
4805 | The repeat count is a decimal integer; the default is 1. It specifies | |
4806 | how much memory (counting by units @var{u}) to display. | |
4807 | @c This really is **decimal**; unaffected by 'set radix' as of GDB | |
4808 | @c 4.1.2. | |
4809 | ||
4810 | @item @var{f}, the display format | |
4811 | The display format is one of the formats used by @code{print}, | |
4812 | @samp{s} (null-terminated string), or @samp{i} (machine instruction). | |
4813 | The default is @samp{x} (hexadecimal) initially. | |
4814 | The default changes each time you use either @code{x} or @code{print}. | |
4815 | ||
4816 | @item @var{u}, the unit size | |
4817 | The unit size is any of | |
4818 | ||
4819 | @table @code | |
4820 | @item b | |
4821 | Bytes. | |
4822 | @item h | |
4823 | Halfwords (two bytes). | |
4824 | @item w | |
4825 | Words (four bytes). This is the initial default. | |
4826 | @item g | |
4827 | Giant words (eight bytes). | |
4828 | @end table | |
4829 | ||
4830 | Each time you specify a unit size with @code{x}, that size becomes the | |
4831 | default unit the next time you use @code{x}. (For the @samp{s} and | |
4832 | @samp{i} formats, the unit size is ignored and is normally not written.) | |
4833 | ||
4834 | @item @var{addr}, starting display address | |
4835 | @var{addr} is the address where you want @value{GDBN} to begin displaying | |
4836 | memory. The expression need not have a pointer value (though it may); | |
4837 | it is always interpreted as an integer address of a byte of memory. | |
4838 | @xref{Expressions, ,Expressions}, for more information on expressions. The default for | |
4839 | @var{addr} is usually just after the last address examined---but several | |
4840 | other commands also set the default address: @code{info breakpoints} (to | |
4841 | the address of the last breakpoint listed), @code{info line} (to the | |
4842 | starting address of a line), and @code{print} (if you use it to display | |
4843 | a value from memory). | |
4844 | @end table | |
4845 | ||
4846 | For example, @samp{x/3uh 0x54320} is a request to display three halfwords | |
4847 | (@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}), | |
4848 | starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four | |
4849 | words (@samp{w}) of memory above the stack pointer (here, @samp{$sp}; | |
d4f3574e | 4850 | @pxref{Registers, ,Registers}) in hexadecimal (@samp{x}). |
c906108c SS |
4851 | |
4852 | Since the letters indicating unit sizes are all distinct from the | |
4853 | letters specifying output formats, you do not have to remember whether | |
4854 | unit size or format comes first; either order works. The output | |
4855 | specifications @samp{4xw} and @samp{4wx} mean exactly the same thing. | |
4856 | (However, the count @var{n} must come first; @samp{wx4} does not work.) | |
4857 | ||
4858 | Even though the unit size @var{u} is ignored for the formats @samp{s} | |
4859 | and @samp{i}, you might still want to use a count @var{n}; for example, | |
4860 | @samp{3i} specifies that you want to see three machine instructions, | |
4861 | including any operands. The command @code{disassemble} gives an | |
d4f3574e | 4862 | alternative way of inspecting machine instructions; see @ref{Machine |
c906108c SS |
4863 | Code,,Source and machine code}. |
4864 | ||
4865 | All the defaults for the arguments to @code{x} are designed to make it | |
4866 | easy to continue scanning memory with minimal specifications each time | |
4867 | you use @code{x}. For example, after you have inspected three machine | |
4868 | instructions with @samp{x/3i @var{addr}}, you can inspect the next seven | |
4869 | with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command, | |
4870 | the repeat count @var{n} is used again; the other arguments default as | |
4871 | for successive uses of @code{x}. | |
4872 | ||
4873 | @cindex @code{$_}, @code{$__}, and value history | |
4874 | The addresses and contents printed by the @code{x} command are not saved | |
4875 | in the value history because there is often too much of them and they | |
4876 | would get in the way. Instead, @value{GDBN} makes these values available for | |
4877 | subsequent use in expressions as values of the convenience variables | |
4878 | @code{$_} and @code{$__}. After an @code{x} command, the last address | |
4879 | examined is available for use in expressions in the convenience variable | |
4880 | @code{$_}. The contents of that address, as examined, are available in | |
4881 | the convenience variable @code{$__}. | |
4882 | ||
4883 | If the @code{x} command has a repeat count, the address and contents saved | |
4884 | are from the last memory unit printed; this is not the same as the last | |
4885 | address printed if several units were printed on the last line of output. | |
4886 | ||
6d2ebf8b | 4887 | @node Auto Display |
c906108c SS |
4888 | @section Automatic display |
4889 | @cindex automatic display | |
4890 | @cindex display of expressions | |
4891 | ||
4892 | If you find that you want to print the value of an expression frequently | |
4893 | (to see how it changes), you might want to add it to the @dfn{automatic | |
4894 | display list} so that @value{GDBN} prints its value each time your program stops. | |
4895 | Each expression added to the list is given a number to identify it; | |
4896 | to remove an expression from the list, you specify that number. | |
4897 | The automatic display looks like this: | |
4898 | ||
4899 | @example | |
4900 | 2: foo = 38 | |
4901 | 3: bar[5] = (struct hack *) 0x3804 | |
4902 | @end example | |
4903 | ||
4904 | @noindent | |
4905 | This display shows item numbers, expressions and their current values. As with | |
4906 | displays you request manually using @code{x} or @code{print}, you can | |
4907 | specify the output format you prefer; in fact, @code{display} decides | |
4908 | whether to use @code{print} or @code{x} depending on how elaborate your | |
4909 | format specification is---it uses @code{x} if you specify a unit size, | |
4910 | or one of the two formats (@samp{i} and @samp{s}) that are only | |
4911 | supported by @code{x}; otherwise it uses @code{print}. | |
4912 | ||
4913 | @table @code | |
4914 | @kindex display | |
d4f3574e SS |
4915 | @item display @var{expr} |
4916 | Add the expression @var{expr} to the list of expressions to display | |
c906108c SS |
4917 | each time your program stops. @xref{Expressions, ,Expressions}. |
4918 | ||
4919 | @code{display} does not repeat if you press @key{RET} again after using it. | |
4920 | ||
d4f3574e | 4921 | @item display/@var{fmt} @var{expr} |
c906108c | 4922 | For @var{fmt} specifying only a display format and not a size or |
d4f3574e | 4923 | count, add the expression @var{expr} to the auto-display list but |
c906108c SS |
4924 | arrange to display it each time in the specified format @var{fmt}. |
4925 | @xref{Output Formats,,Output formats}. | |
4926 | ||
4927 | @item display/@var{fmt} @var{addr} | |
4928 | For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a | |
4929 | number of units, add the expression @var{addr} as a memory address to | |
4930 | be examined each time your program stops. Examining means in effect | |
4931 | doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining memory}. | |
4932 | @end table | |
4933 | ||
4934 | For example, @samp{display/i $pc} can be helpful, to see the machine | |
4935 | instruction about to be executed each time execution stops (@samp{$pc} | |
d4f3574e | 4936 | is a common name for the program counter; @pxref{Registers, ,Registers}). |
c906108c SS |
4937 | |
4938 | @table @code | |
4939 | @kindex delete display | |
4940 | @kindex undisplay | |
4941 | @item undisplay @var{dnums}@dots{} | |
4942 | @itemx delete display @var{dnums}@dots{} | |
4943 | Remove item numbers @var{dnums} from the list of expressions to display. | |
4944 | ||
4945 | @code{undisplay} does not repeat if you press @key{RET} after using it. | |
4946 | (Otherwise you would just get the error @samp{No display number @dots{}}.) | |
4947 | ||
4948 | @kindex disable display | |
4949 | @item disable display @var{dnums}@dots{} | |
4950 | Disable the display of item numbers @var{dnums}. A disabled display | |
4951 | item is not printed automatically, but is not forgotten. It may be | |
4952 | enabled again later. | |
4953 | ||
4954 | @kindex enable display | |
4955 | @item enable display @var{dnums}@dots{} | |
4956 | Enable display of item numbers @var{dnums}. It becomes effective once | |
4957 | again in auto display of its expression, until you specify otherwise. | |
4958 | ||
4959 | @item display | |
4960 | Display the current values of the expressions on the list, just as is | |
4961 | done when your program stops. | |
4962 | ||
4963 | @kindex info display | |
4964 | @item info display | |
4965 | Print the list of expressions previously set up to display | |
4966 | automatically, each one with its item number, but without showing the | |
4967 | values. This includes disabled expressions, which are marked as such. | |
4968 | It also includes expressions which would not be displayed right now | |
4969 | because they refer to automatic variables not currently available. | |
4970 | @end table | |
4971 | ||
4972 | If a display expression refers to local variables, then it does not make | |
4973 | sense outside the lexical context for which it was set up. Such an | |
4974 | expression is disabled when execution enters a context where one of its | |
4975 | variables is not defined. For example, if you give the command | |
4976 | @code{display last_char} while inside a function with an argument | |
4977 | @code{last_char}, @value{GDBN} displays this argument while your program | |
4978 | continues to stop inside that function. When it stops elsewhere---where | |
4979 | there is no variable @code{last_char}---the display is disabled | |
4980 | automatically. The next time your program stops where @code{last_char} | |
4981 | is meaningful, you can enable the display expression once again. | |
4982 | ||
6d2ebf8b | 4983 | @node Print Settings |
c906108c SS |
4984 | @section Print settings |
4985 | ||
4986 | @cindex format options | |
4987 | @cindex print settings | |
4988 | @value{GDBN} provides the following ways to control how arrays, structures, | |
4989 | and symbols are printed. | |
4990 | ||
4991 | @noindent | |
4992 | These settings are useful for debugging programs in any language: | |
4993 | ||
4994 | @table @code | |
4995 | @kindex set print address | |
4996 | @item set print address | |
4997 | @itemx set print address on | |
4998 | @value{GDBN} prints memory addresses showing the location of stack | |
4999 | traces, structure values, pointer values, breakpoints, and so forth, | |
5000 | even when it also displays the contents of those addresses. The default | |
5001 | is @code{on}. For example, this is what a stack frame display looks like with | |
5002 | @code{set print address on}: | |
5003 | ||
5004 | @smallexample | |
5005 | @group | |
5006 | (@value{GDBP}) f | |
5007 | #0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>") | |
5008 | at input.c:530 | |
5009 | 530 if (lquote != def_lquote) | |
5010 | @end group | |
5011 | @end smallexample | |
5012 | ||
5013 | @item set print address off | |
5014 | Do not print addresses when displaying their contents. For example, | |
5015 | this is the same stack frame displayed with @code{set print address off}: | |
5016 | ||
5017 | @smallexample | |
5018 | @group | |
5019 | (@value{GDBP}) set print addr off | |
5020 | (@value{GDBP}) f | |
5021 | #0 set_quotes (lq="<<", rq=">>") at input.c:530 | |
5022 | 530 if (lquote != def_lquote) | |
5023 | @end group | |
5024 | @end smallexample | |
5025 | ||
5026 | You can use @samp{set print address off} to eliminate all machine | |
5027 | dependent displays from the @value{GDBN} interface. For example, with | |
5028 | @code{print address off}, you should get the same text for backtraces on | |
5029 | all machines---whether or not they involve pointer arguments. | |
5030 | ||
5031 | @kindex show print address | |
5032 | @item show print address | |
5033 | Show whether or not addresses are to be printed. | |
5034 | @end table | |
5035 | ||
5036 | When @value{GDBN} prints a symbolic address, it normally prints the | |
5037 | closest earlier symbol plus an offset. If that symbol does not uniquely | |
5038 | identify the address (for example, it is a name whose scope is a single | |
5039 | source file), you may need to clarify. One way to do this is with | |
5040 | @code{info line}, for example @samp{info line *0x4537}. Alternately, | |
5041 | you can set @value{GDBN} to print the source file and line number when | |
5042 | it prints a symbolic address: | |
5043 | ||
5044 | @table @code | |
5045 | @kindex set print symbol-filename | |
5046 | @item set print symbol-filename on | |
5047 | Tell @value{GDBN} to print the source file name and line number of a | |
5048 | symbol in the symbolic form of an address. | |
5049 | ||
5050 | @item set print symbol-filename off | |
5051 | Do not print source file name and line number of a symbol. This is the | |
5052 | default. | |
5053 | ||
5054 | @kindex show print symbol-filename | |
5055 | @item show print symbol-filename | |
5056 | Show whether or not @value{GDBN} will print the source file name and | |
5057 | line number of a symbol in the symbolic form of an address. | |
5058 | @end table | |
5059 | ||
5060 | Another situation where it is helpful to show symbol filenames and line | |
5061 | numbers is when disassembling code; @value{GDBN} shows you the line | |
5062 | number and source file that corresponds to each instruction. | |
5063 | ||
5064 | Also, you may wish to see the symbolic form only if the address being | |
5065 | printed is reasonably close to the closest earlier symbol: | |
5066 | ||
5067 | @table @code | |
5068 | @kindex set print max-symbolic-offset | |
5069 | @item set print max-symbolic-offset @var{max-offset} | |
5070 | Tell @value{GDBN} to only display the symbolic form of an address if the | |
5071 | offset between the closest earlier symbol and the address is less than | |
5d161b24 | 5072 | @var{max-offset}. The default is 0, which tells @value{GDBN} |
c906108c SS |
5073 | to always print the symbolic form of an address if any symbol precedes it. |
5074 | ||
5075 | @kindex show print max-symbolic-offset | |
5076 | @item show print max-symbolic-offset | |
5077 | Ask how large the maximum offset is that @value{GDBN} prints in a | |
5078 | symbolic address. | |
5079 | @end table | |
5080 | ||
5081 | @cindex wild pointer, interpreting | |
5082 | @cindex pointer, finding referent | |
5083 | If you have a pointer and you are not sure where it points, try | |
5084 | @samp{set print symbol-filename on}. Then you can determine the name | |
5085 | and source file location of the variable where it points, using | |
5086 | @samp{p/a @var{pointer}}. This interprets the address in symbolic form. | |
5087 | For example, here @value{GDBN} shows that a variable @code{ptt} points | |
5088 | at another variable @code{t}, defined in @file{hi2.c}: | |
5089 | ||
5090 | @example | |
5091 | (@value{GDBP}) set print symbol-filename on | |
5092 | (@value{GDBP}) p/a ptt | |
5093 | $4 = 0xe008 <t in hi2.c> | |
5094 | @end example | |
5095 | ||
5096 | @quotation | |
5097 | @emph{Warning:} For pointers that point to a local variable, @samp{p/a} | |
5098 | does not show the symbol name and filename of the referent, even with | |
5099 | the appropriate @code{set print} options turned on. | |
5100 | @end quotation | |
5101 | ||
5102 | Other settings control how different kinds of objects are printed: | |
5103 | ||
5104 | @table @code | |
5105 | @kindex set print array | |
5106 | @item set print array | |
5107 | @itemx set print array on | |
5108 | Pretty print arrays. This format is more convenient to read, | |
5109 | but uses more space. The default is off. | |
5110 | ||
5111 | @item set print array off | |
5112 | Return to compressed format for arrays. | |
5113 | ||
5114 | @kindex show print array | |
5115 | @item show print array | |
5116 | Show whether compressed or pretty format is selected for displaying | |
5117 | arrays. | |
5118 | ||
5119 | @kindex set print elements | |
5120 | @item set print elements @var{number-of-elements} | |
5121 | Set a limit on how many elements of an array @value{GDBN} will print. | |
5122 | If @value{GDBN} is printing a large array, it stops printing after it has | |
5123 | printed the number of elements set by the @code{set print elements} command. | |
5124 | This limit also applies to the display of strings. | |
d4f3574e | 5125 | When @value{GDBN} starts, this limit is set to 200. |
c906108c SS |
5126 | Setting @var{number-of-elements} to zero means that the printing is unlimited. |
5127 | ||
5128 | @kindex show print elements | |
5129 | @item show print elements | |
5130 | Display the number of elements of a large array that @value{GDBN} will print. | |
5131 | If the number is 0, then the printing is unlimited. | |
5132 | ||
5133 | @kindex set print null-stop | |
5134 | @item set print null-stop | |
5135 | Cause @value{GDBN} to stop printing the characters of an array when the first | |
d4f3574e | 5136 | @sc{null} is encountered. This is useful when large arrays actually |
c906108c | 5137 | contain only short strings. |
d4f3574e | 5138 | The default is off. |
c906108c SS |
5139 | |
5140 | @kindex set print pretty | |
5141 | @item set print pretty on | |
5d161b24 | 5142 | Cause @value{GDBN} to print structures in an indented format with one member |
c906108c SS |
5143 | per line, like this: |
5144 | ||
5145 | @smallexample | |
5146 | @group | |
5147 | $1 = @{ | |
5148 | next = 0x0, | |
5149 | flags = @{ | |
5150 | sweet = 1, | |
5151 | sour = 1 | |
5152 | @}, | |
5153 | meat = 0x54 "Pork" | |
5154 | @} | |
5155 | @end group | |
5156 | @end smallexample | |
5157 | ||
5158 | @item set print pretty off | |
5159 | Cause @value{GDBN} to print structures in a compact format, like this: | |
5160 | ||
5161 | @smallexample | |
5162 | @group | |
5163 | $1 = @{next = 0x0, flags = @{sweet = 1, sour = 1@}, \ | |
5164 | meat = 0x54 "Pork"@} | |
5165 | @end group | |
5166 | @end smallexample | |
5167 | ||
5168 | @noindent | |
5169 | This is the default format. | |
5170 | ||
5171 | @kindex show print pretty | |
5172 | @item show print pretty | |
5173 | Show which format @value{GDBN} is using to print structures. | |
5174 | ||
5175 | @kindex set print sevenbit-strings | |
5176 | @item set print sevenbit-strings on | |
5177 | Print using only seven-bit characters; if this option is set, | |
5178 | @value{GDBN} displays any eight-bit characters (in strings or | |
5179 | character values) using the notation @code{\}@var{nnn}. This setting is | |
5180 | best if you are working in English (@sc{ascii}) and you use the | |
5181 | high-order bit of characters as a marker or ``meta'' bit. | |
5182 | ||
5183 | @item set print sevenbit-strings off | |
5184 | Print full eight-bit characters. This allows the use of more | |
5185 | international character sets, and is the default. | |
5186 | ||
5187 | @kindex show print sevenbit-strings | |
5188 | @item show print sevenbit-strings | |
5189 | Show whether or not @value{GDBN} is printing only seven-bit characters. | |
5190 | ||
5191 | @kindex set print union | |
5192 | @item set print union on | |
5d161b24 | 5193 | Tell @value{GDBN} to print unions which are contained in structures. This |
c906108c SS |
5194 | is the default setting. |
5195 | ||
5196 | @item set print union off | |
5197 | Tell @value{GDBN} not to print unions which are contained in structures. | |
5198 | ||
5199 | @kindex show print union | |
5200 | @item show print union | |
5201 | Ask @value{GDBN} whether or not it will print unions which are contained in | |
5202 | structures. | |
5203 | ||
5204 | For example, given the declarations | |
5205 | ||
5206 | @smallexample | |
5207 | typedef enum @{Tree, Bug@} Species; | |
5208 | typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms; | |
5d161b24 | 5209 | typedef enum @{Caterpillar, Cocoon, Butterfly@} |
c906108c SS |
5210 | Bug_forms; |
5211 | ||
5212 | struct thing @{ | |
5213 | Species it; | |
5214 | union @{ | |
5215 | Tree_forms tree; | |
5216 | Bug_forms bug; | |
5217 | @} form; | |
5218 | @}; | |
5219 | ||
5220 | struct thing foo = @{Tree, @{Acorn@}@}; | |
5221 | @end smallexample | |
5222 | ||
5223 | @noindent | |
5224 | with @code{set print union on} in effect @samp{p foo} would print | |
5225 | ||
5226 | @smallexample | |
5227 | $1 = @{it = Tree, form = @{tree = Acorn, bug = Cocoon@}@} | |
5228 | @end smallexample | |
5229 | ||
5230 | @noindent | |
5231 | and with @code{set print union off} in effect it would print | |
5232 | ||
5233 | @smallexample | |
5234 | $1 = @{it = Tree, form = @{...@}@} | |
5235 | @end smallexample | |
5236 | @end table | |
5237 | ||
c906108c SS |
5238 | @need 1000 |
5239 | @noindent | |
b37052ae | 5240 | These settings are of interest when debugging C@t{++} programs: |
c906108c SS |
5241 | |
5242 | @table @code | |
5243 | @cindex demangling | |
5244 | @kindex set print demangle | |
5245 | @item set print demangle | |
5246 | @itemx set print demangle on | |
b37052ae | 5247 | Print C@t{++} names in their source form rather than in the encoded |
c906108c | 5248 | (``mangled'') form passed to the assembler and linker for type-safe |
d4f3574e | 5249 | linkage. The default is on. |
c906108c SS |
5250 | |
5251 | @kindex show print demangle | |
5252 | @item show print demangle | |
b37052ae | 5253 | Show whether C@t{++} names are printed in mangled or demangled form. |
c906108c SS |
5254 | |
5255 | @kindex set print asm-demangle | |
5256 | @item set print asm-demangle | |
5257 | @itemx set print asm-demangle on | |
b37052ae | 5258 | Print C@t{++} names in their source form rather than their mangled form, even |
c906108c SS |
5259 | in assembler code printouts such as instruction disassemblies. |
5260 | The default is off. | |
5261 | ||
5262 | @kindex show print asm-demangle | |
5263 | @item show print asm-demangle | |
b37052ae | 5264 | Show whether C@t{++} names in assembly listings are printed in mangled |
c906108c SS |
5265 | or demangled form. |
5266 | ||
5267 | @kindex set demangle-style | |
b37052ae EZ |
5268 | @cindex C@t{++} symbol decoding style |
5269 | @cindex symbol decoding style, C@t{++} | |
c906108c SS |
5270 | @item set demangle-style @var{style} |
5271 | Choose among several encoding schemes used by different compilers to | |
b37052ae | 5272 | represent C@t{++} names. The choices for @var{style} are currently: |
c906108c SS |
5273 | |
5274 | @table @code | |
5275 | @item auto | |
5276 | Allow @value{GDBN} to choose a decoding style by inspecting your program. | |
5277 | ||
5278 | @item gnu | |
b37052ae | 5279 | Decode based on the @sc{gnu} C@t{++} compiler (@code{g++}) encoding algorithm. |
c906108c | 5280 | This is the default. |
c906108c SS |
5281 | |
5282 | @item hp | |
b37052ae | 5283 | Decode based on the HP ANSI C@t{++} (@code{aCC}) encoding algorithm. |
c906108c SS |
5284 | |
5285 | @item lucid | |
b37052ae | 5286 | Decode based on the Lucid C@t{++} compiler (@code{lcc}) encoding algorithm. |
c906108c SS |
5287 | |
5288 | @item arm | |
b37052ae | 5289 | Decode using the algorithm in the @cite{C@t{++} Annotated Reference Manual}. |
c906108c SS |
5290 | @strong{Warning:} this setting alone is not sufficient to allow |
5291 | debugging @code{cfront}-generated executables. @value{GDBN} would | |
5292 | require further enhancement to permit that. | |
5293 | ||
5294 | @end table | |
5295 | If you omit @var{style}, you will see a list of possible formats. | |
5296 | ||
5297 | @kindex show demangle-style | |
5298 | @item show demangle-style | |
b37052ae | 5299 | Display the encoding style currently in use for decoding C@t{++} symbols. |
c906108c SS |
5300 | |
5301 | @kindex set print object | |
5302 | @item set print object | |
5303 | @itemx set print object on | |
5304 | When displaying a pointer to an object, identify the @emph{actual} | |
5305 | (derived) type of the object rather than the @emph{declared} type, using | |
5306 | the virtual function table. | |
5307 | ||
5308 | @item set print object off | |
5309 | Display only the declared type of objects, without reference to the | |
5310 | virtual function table. This is the default setting. | |
5311 | ||
5312 | @kindex show print object | |
5313 | @item show print object | |
5314 | Show whether actual, or declared, object types are displayed. | |
5315 | ||
5316 | @kindex set print static-members | |
5317 | @item set print static-members | |
5318 | @itemx set print static-members on | |
b37052ae | 5319 | Print static members when displaying a C@t{++} object. The default is on. |
c906108c SS |
5320 | |
5321 | @item set print static-members off | |
b37052ae | 5322 | Do not print static members when displaying a C@t{++} object. |
c906108c SS |
5323 | |
5324 | @kindex show print static-members | |
5325 | @item show print static-members | |
b37052ae | 5326 | Show whether C@t{++} static members are printed, or not. |
c906108c SS |
5327 | |
5328 | @c These don't work with HP ANSI C++ yet. | |
5329 | @kindex set print vtbl | |
5330 | @item set print vtbl | |
5331 | @itemx set print vtbl on | |
b37052ae | 5332 | Pretty print C@t{++} virtual function tables. The default is off. |
c906108c | 5333 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 5334 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
5335 | |
5336 | @item set print vtbl off | |
b37052ae | 5337 | Do not pretty print C@t{++} virtual function tables. |
c906108c SS |
5338 | |
5339 | @kindex show print vtbl | |
5340 | @item show print vtbl | |
b37052ae | 5341 | Show whether C@t{++} virtual function tables are pretty printed, or not. |
c906108c | 5342 | @end table |
c906108c | 5343 | |
6d2ebf8b | 5344 | @node Value History |
c906108c SS |
5345 | @section Value history |
5346 | ||
5347 | @cindex value history | |
5d161b24 DB |
5348 | Values printed by the @code{print} command are saved in the @value{GDBN} |
5349 | @dfn{value history}. This allows you to refer to them in other expressions. | |
5350 | Values are kept until the symbol table is re-read or discarded | |
5351 | (for example with the @code{file} or @code{symbol-file} commands). | |
5352 | When the symbol table changes, the value history is discarded, | |
5353 | since the values may contain pointers back to the types defined in the | |
c906108c SS |
5354 | symbol table. |
5355 | ||
5356 | @cindex @code{$} | |
5357 | @cindex @code{$$} | |
5358 | @cindex history number | |
5359 | The values printed are given @dfn{history numbers} by which you can | |
5360 | refer to them. These are successive integers starting with one. | |
5361 | @code{print} shows you the history number assigned to a value by | |
5362 | printing @samp{$@var{num} = } before the value; here @var{num} is the | |
5363 | history number. | |
5364 | ||
5365 | To refer to any previous value, use @samp{$} followed by the value's | |
5366 | history number. The way @code{print} labels its output is designed to | |
5367 | remind you of this. Just @code{$} refers to the most recent value in | |
5368 | the history, and @code{$$} refers to the value before that. | |
5369 | @code{$$@var{n}} refers to the @var{n}th value from the end; @code{$$2} | |
5370 | is the value just prior to @code{$$}, @code{$$1} is equivalent to | |
5371 | @code{$$}, and @code{$$0} is equivalent to @code{$}. | |
5372 | ||
5373 | For example, suppose you have just printed a pointer to a structure and | |
5374 | want to see the contents of the structure. It suffices to type | |
5375 | ||
5376 | @example | |
5377 | p *$ | |
5378 | @end example | |
5379 | ||
5380 | If you have a chain of structures where the component @code{next} points | |
5381 | to the next one, you can print the contents of the next one with this: | |
5382 | ||
5383 | @example | |
5384 | p *$.next | |
5385 | @end example | |
5386 | ||
5387 | @noindent | |
5388 | You can print successive links in the chain by repeating this | |
5389 | command---which you can do by just typing @key{RET}. | |
5390 | ||
5391 | Note that the history records values, not expressions. If the value of | |
5392 | @code{x} is 4 and you type these commands: | |
5393 | ||
5394 | @example | |
5395 | print x | |
5396 | set x=5 | |
5397 | @end example | |
5398 | ||
5399 | @noindent | |
5400 | then the value recorded in the value history by the @code{print} command | |
5401 | remains 4 even though the value of @code{x} has changed. | |
5402 | ||
5403 | @table @code | |
5404 | @kindex show values | |
5405 | @item show values | |
5406 | Print the last ten values in the value history, with their item numbers. | |
5407 | This is like @samp{p@ $$9} repeated ten times, except that @code{show | |
5408 | values} does not change the history. | |
5409 | ||
5410 | @item show values @var{n} | |
5411 | Print ten history values centered on history item number @var{n}. | |
5412 | ||
5413 | @item show values + | |
5414 | Print ten history values just after the values last printed. If no more | |
5415 | values are available, @code{show values +} produces no display. | |
5416 | @end table | |
5417 | ||
5418 | Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the | |
5419 | same effect as @samp{show values +}. | |
5420 | ||
6d2ebf8b | 5421 | @node Convenience Vars |
c906108c SS |
5422 | @section Convenience variables |
5423 | ||
5424 | @cindex convenience variables | |
5425 | @value{GDBN} provides @dfn{convenience variables} that you can use within | |
5426 | @value{GDBN} to hold on to a value and refer to it later. These variables | |
5427 | exist entirely within @value{GDBN}; they are not part of your program, and | |
5428 | setting a convenience variable has no direct effect on further execution | |
5429 | of your program. That is why you can use them freely. | |
5430 | ||
5431 | Convenience variables are prefixed with @samp{$}. Any name preceded by | |
5432 | @samp{$} can be used for a convenience variable, unless it is one of | |
d4f3574e | 5433 | the predefined machine-specific register names (@pxref{Registers, ,Registers}). |
c906108c SS |
5434 | (Value history references, in contrast, are @emph{numbers} preceded |
5435 | by @samp{$}. @xref{Value History, ,Value history}.) | |
5436 | ||
5437 | You can save a value in a convenience variable with an assignment | |
5438 | expression, just as you would set a variable in your program. | |
5439 | For example: | |
5440 | ||
5441 | @example | |
5442 | set $foo = *object_ptr | |
5443 | @end example | |
5444 | ||
5445 | @noindent | |
5446 | would save in @code{$foo} the value contained in the object pointed to by | |
5447 | @code{object_ptr}. | |
5448 | ||
5449 | Using a convenience variable for the first time creates it, but its | |
5450 | value is @code{void} until you assign a new value. You can alter the | |
5451 | value with another assignment at any time. | |
5452 | ||
5453 | Convenience variables have no fixed types. You can assign a convenience | |
5454 | variable any type of value, including structures and arrays, even if | |
5455 | that variable already has a value of a different type. The convenience | |
5456 | variable, when used as an expression, has the type of its current value. | |
5457 | ||
5458 | @table @code | |
5459 | @kindex show convenience | |
5460 | @item show convenience | |
5461 | Print a list of convenience variables used so far, and their values. | |
d4f3574e | 5462 | Abbreviated @code{show conv}. |
c906108c SS |
5463 | @end table |
5464 | ||
5465 | One of the ways to use a convenience variable is as a counter to be | |
5466 | incremented or a pointer to be advanced. For example, to print | |
5467 | a field from successive elements of an array of structures: | |
5468 | ||
5469 | @example | |
5470 | set $i = 0 | |
5471 | print bar[$i++]->contents | |
5472 | @end example | |
5473 | ||
d4f3574e SS |
5474 | @noindent |
5475 | Repeat that command by typing @key{RET}. | |
c906108c SS |
5476 | |
5477 | Some convenience variables are created automatically by @value{GDBN} and given | |
5478 | values likely to be useful. | |
5479 | ||
5480 | @table @code | |
41afff9a | 5481 | @vindex $_@r{, convenience variable} |
c906108c SS |
5482 | @item $_ |
5483 | The variable @code{$_} is automatically set by the @code{x} command to | |
5484 | the last address examined (@pxref{Memory, ,Examining memory}). Other | |
5485 | commands which provide a default address for @code{x} to examine also | |
5486 | set @code{$_} to that address; these commands include @code{info line} | |
5487 | and @code{info breakpoint}. The type of @code{$_} is @code{void *} | |
5488 | except when set by the @code{x} command, in which case it is a pointer | |
5489 | to the type of @code{$__}. | |
5490 | ||
41afff9a | 5491 | @vindex $__@r{, convenience variable} |
c906108c SS |
5492 | @item $__ |
5493 | The variable @code{$__} is automatically set by the @code{x} command | |
5494 | to the value found in the last address examined. Its type is chosen | |
5495 | to match the format in which the data was printed. | |
5496 | ||
5497 | @item $_exitcode | |
41afff9a | 5498 | @vindex $_exitcode@r{, convenience variable} |
c906108c SS |
5499 | The variable @code{$_exitcode} is automatically set to the exit code when |
5500 | the program being debugged terminates. | |
5501 | @end table | |
5502 | ||
53a5351d JM |
5503 | On HP-UX systems, if you refer to a function or variable name that |
5504 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
5505 | name first, before it searches for a convenience variable. | |
c906108c | 5506 | |
6d2ebf8b | 5507 | @node Registers |
c906108c SS |
5508 | @section Registers |
5509 | ||
5510 | @cindex registers | |
5511 | You can refer to machine register contents, in expressions, as variables | |
5512 | with names starting with @samp{$}. The names of registers are different | |
5513 | for each machine; use @code{info registers} to see the names used on | |
5514 | your machine. | |
5515 | ||
5516 | @table @code | |
5517 | @kindex info registers | |
5518 | @item info registers | |
5519 | Print the names and values of all registers except floating-point | |
5520 | registers (in the selected stack frame). | |
5521 | ||
5522 | @kindex info all-registers | |
5523 | @cindex floating point registers | |
5524 | @item info all-registers | |
5525 | Print the names and values of all registers, including floating-point | |
5526 | registers. | |
5527 | ||
5528 | @item info registers @var{regname} @dots{} | |
5529 | Print the @dfn{relativized} value of each specified register @var{regname}. | |
5d161b24 DB |
5530 | As discussed in detail below, register values are normally relative to |
5531 | the selected stack frame. @var{regname} may be any register name valid on | |
c906108c SS |
5532 | the machine you are using, with or without the initial @samp{$}. |
5533 | @end table | |
5534 | ||
5535 | @value{GDBN} has four ``standard'' register names that are available (in | |
5536 | expressions) on most machines---whenever they do not conflict with an | |
5537 | architecture's canonical mnemonics for registers. The register names | |
5538 | @code{$pc} and @code{$sp} are used for the program counter register and | |
5539 | the stack pointer. @code{$fp} is used for a register that contains a | |
5540 | pointer to the current stack frame, and @code{$ps} is used for a | |
5541 | register that contains the processor status. For example, | |
5542 | you could print the program counter in hex with | |
5543 | ||
5544 | @example | |
5545 | p/x $pc | |
5546 | @end example | |
5547 | ||
5548 | @noindent | |
5549 | or print the instruction to be executed next with | |
5550 | ||
5551 | @example | |
5552 | x/i $pc | |
5553 | @end example | |
5554 | ||
5555 | @noindent | |
5556 | or add four to the stack pointer@footnote{This is a way of removing | |
5557 | one word from the stack, on machines where stacks grow downward in | |
5558 | memory (most machines, nowadays). This assumes that the innermost | |
5559 | stack frame is selected; setting @code{$sp} is not allowed when other | |
5560 | stack frames are selected. To pop entire frames off the stack, | |
5561 | regardless of machine architecture, use @code{return}; | |
d4f3574e | 5562 | see @ref{Returning, ,Returning from a function}.} with |
c906108c SS |
5563 | |
5564 | @example | |
5565 | set $sp += 4 | |
5566 | @end example | |
5567 | ||
5568 | Whenever possible, these four standard register names are available on | |
5569 | your machine even though the machine has different canonical mnemonics, | |
5570 | so long as there is no conflict. The @code{info registers} command | |
5571 | shows the canonical names. For example, on the SPARC, @code{info | |
5572 | registers} displays the processor status register as @code{$psr} but you | |
d4f3574e SS |
5573 | can also refer to it as @code{$ps}; and on x86-based machines @code{$ps} |
5574 | is an alias for the @sc{eflags} register. | |
c906108c SS |
5575 | |
5576 | @value{GDBN} always considers the contents of an ordinary register as an | |
5577 | integer when the register is examined in this way. Some machines have | |
5578 | special registers which can hold nothing but floating point; these | |
5579 | registers are considered to have floating point values. There is no way | |
5580 | to refer to the contents of an ordinary register as floating point value | |
5581 | (although you can @emph{print} it as a floating point value with | |
5582 | @samp{print/f $@var{regname}}). | |
5583 | ||
5584 | Some registers have distinct ``raw'' and ``virtual'' data formats. This | |
5585 | means that the data format in which the register contents are saved by | |
5586 | the operating system is not the same one that your program normally | |
5587 | sees. For example, the registers of the 68881 floating point | |
5588 | coprocessor are always saved in ``extended'' (raw) format, but all C | |
5589 | programs expect to work with ``double'' (virtual) format. In such | |
5d161b24 | 5590 | cases, @value{GDBN} normally works with the virtual format only (the format |
c906108c SS |
5591 | that makes sense for your program), but the @code{info registers} command |
5592 | prints the data in both formats. | |
5593 | ||
5594 | Normally, register values are relative to the selected stack frame | |
5595 | (@pxref{Selection, ,Selecting a frame}). This means that you get the | |
5596 | value that the register would contain if all stack frames farther in | |
5597 | were exited and their saved registers restored. In order to see the | |
5598 | true contents of hardware registers, you must select the innermost | |
5599 | frame (with @samp{frame 0}). | |
5600 | ||
5601 | However, @value{GDBN} must deduce where registers are saved, from the machine | |
5602 | code generated by your compiler. If some registers are not saved, or if | |
5603 | @value{GDBN} is unable to locate the saved registers, the selected stack | |
5604 | frame makes no difference. | |
5605 | ||
6d2ebf8b | 5606 | @node Floating Point Hardware |
c906108c SS |
5607 | @section Floating point hardware |
5608 | @cindex floating point | |
5609 | ||
5610 | Depending on the configuration, @value{GDBN} may be able to give | |
5611 | you more information about the status of the floating point hardware. | |
5612 | ||
5613 | @table @code | |
5614 | @kindex info float | |
5615 | @item info float | |
5616 | Display hardware-dependent information about the floating | |
5617 | point unit. The exact contents and layout vary depending on the | |
5618 | floating point chip. Currently, @samp{info float} is supported on | |
5619 | the ARM and x86 machines. | |
5620 | @end table | |
c906108c | 5621 | |
29e57380 C |
5622 | @node Memory Region Attributes |
5623 | @section Memory Region Attributes | |
5624 | @cindex memory region attributes | |
5625 | ||
5626 | @dfn{Memory region attributes} allow you to describe special handling | |
5627 | required by regions of your target's memory. @value{GDBN} uses attributes | |
5628 | to determine whether to allow certain types of memory accesses; whether to | |
5629 | use specific width accesses; and whether to cache target memory. | |
5630 | ||
5631 | Defined memory regions can be individually enabled and disabled. When a | |
5632 | memory region is disabled, @value{GDBN} uses the default attributes when | |
5633 | accessing memory in that region. Similarly, if no memory regions have | |
5634 | been defined, @value{GDBN} uses the default attributes when accessing | |
5635 | all memory. | |
5636 | ||
5637 | When a memory region is defined, it is given a number to identify it; | |
5638 | to enable, disable, or remove a memory region, you specify that number. | |
5639 | ||
5640 | @table @code | |
5641 | @kindex mem | |
5642 | @item mem @var{address1} @var{address1} @var{attributes}@dots{} | |
5643 | Define memory region bounded by @var{address1} and @var{address2} | |
5644 | with attributes @var{attributes}@dots{}. | |
5645 | ||
5646 | @kindex delete mem | |
5647 | @item delete mem @var{nums}@dots{} | |
5648 | Remove memory region numbers @var{nums}. | |
5649 | ||
5650 | @kindex disable mem | |
5651 | @item disable mem @var{nums}@dots{} | |
5652 | Disable memory region numbers @var{nums}. | |
5653 | A disabled memory region is not forgotten. | |
5654 | It may be enabled again later. | |
5655 | ||
5656 | @kindex enable mem | |
5657 | @item enable mem @var{nums}@dots{} | |
5658 | Enable memory region numbers @var{nums}. | |
5659 | ||
5660 | @kindex info mem | |
5661 | @item info mem | |
5662 | Print a table of all defined memory regions, with the following columns | |
5663 | for each region. | |
5664 | ||
5665 | @table @emph | |
5666 | @item Memory Region Number | |
5667 | @item Enabled or Disabled. | |
5668 | Enabled memory regions are marked with @samp{y}. | |
5669 | Disabled memory regions are marked with @samp{n}. | |
5670 | ||
5671 | @item Lo Address | |
5672 | The address defining the inclusive lower bound of the memory region. | |
5673 | ||
5674 | @item Hi Address | |
5675 | The address defining the exclusive upper bound of the memory region. | |
5676 | ||
5677 | @item Attributes | |
5678 | The list of attributes set for this memory region. | |
5679 | @end table | |
5680 | @end table | |
5681 | ||
5682 | ||
5683 | @subsection Attributes | |
5684 | ||
5685 | @subsubsection Memory Access Mode | |
5686 | The access mode attributes set whether @value{GDBN} may make read or | |
5687 | write accesses to a memory region. | |
5688 | ||
5689 | While these attributes prevent @value{GDBN} from performing invalid | |
5690 | memory accesses, they do nothing to prevent the target system, I/O DMA, | |
5691 | etc. from accessing memory. | |
5692 | ||
5693 | @table @code | |
5694 | @item ro | |
5695 | Memory is read only. | |
5696 | @item wo | |
5697 | Memory is write only. | |
5698 | @item rw | |
5699 | Memory is read/write (default). | |
5700 | @end table | |
5701 | ||
5702 | @subsubsection Memory Access Size | |
5703 | The acccess size attributes tells @value{GDBN} to use specific sized | |
5704 | accesses in the memory region. Often memory mapped device registers | |
5705 | require specific sized accesses. If no access size attribute is | |
5706 | specified, @value{GDBN} may use accesses of any size. | |
5707 | ||
5708 | @table @code | |
5709 | @item 8 | |
5710 | Use 8 bit memory accesses. | |
5711 | @item 16 | |
5712 | Use 16 bit memory accesses. | |
5713 | @item 32 | |
5714 | Use 32 bit memory accesses. | |
5715 | @item 64 | |
5716 | Use 64 bit memory accesses. | |
5717 | @end table | |
5718 | ||
5719 | @c @subsubsection Hardware/Software Breakpoints | |
5720 | @c The hardware/software breakpoint attributes set whether @value{GDBN} | |
5721 | @c will use hardware or software breakpoints for the internal breakpoints | |
5722 | @c used by the step, next, finish, until, etc. commands. | |
5723 | @c | |
5724 | @c @table @code | |
5725 | @c @item hwbreak | |
5726 | @c Always use hardware breakpoints | |
5727 | @c @item swbreak (default) | |
5728 | @c @end table | |
5729 | ||
5730 | @subsubsection Data Cache | |
5731 | The data cache attributes set whether @value{GDBN} will cache target | |
5732 | memory. While this generally improves performance by reducing debug | |
5733 | protocol overhead, it can lead to incorrect results because @value{GDBN} | |
5734 | does not know about volatile variables or memory mapped device | |
5735 | registers. | |
5736 | ||
5737 | @table @code | |
5738 | @item cache | |
5739 | Enable @value{GDBN} to cache target memory. | |
5740 | @item nocache (default) | |
5741 | Disable @value{GDBN} from caching target memory. | |
5742 | @end table | |
5743 | ||
5744 | @c @subsubsection Memory Write Verification | |
5745 | @c The memory write verification attributes set whether @value{GDBN} | |
5746 | @c will re-reads data after each write to verify the write was successful. | |
5747 | @c | |
5748 | @c @table @code | |
5749 | @c @item verify | |
5750 | @c @item noverify (default) | |
5751 | @c @end table | |
5752 | ||
b37052ae EZ |
5753 | @node Tracepoints |
5754 | @chapter Tracepoints | |
5755 | @c This chapter is based on the documentation written by Michael | |
5756 | @c Snyder, David Taylor, Jim Blandy, and Elena Zannoni. | |
5757 | ||
5758 | @cindex tracepoints | |
5759 | In some applications, it is not feasible for the debugger to interrupt | |
5760 | the program's execution long enough for the developer to learn | |
5761 | anything helpful about its behavior. If the program's correctness | |
5762 | depends on its real-time behavior, delays introduced by a debugger | |
5763 | might cause the program to change its behavior drastically, or perhaps | |
5764 | fail, even when the code itself is correct. It is useful to be able | |
5765 | to observe the program's behavior without interrupting it. | |
5766 | ||
5767 | Using @value{GDBN}'s @code{trace} and @code{collect} commands, you can | |
5768 | specify locations in the program, called @dfn{tracepoints}, and | |
5769 | arbitrary expressions to evaluate when those tracepoints are reached. | |
5770 | Later, using the @code{tfind} command, you can examine the values | |
5771 | those expressions had when the program hit the tracepoints. The | |
5772 | expressions may also denote objects in memory---structures or arrays, | |
5773 | for example---whose values @value{GDBN} should record; while visiting | |
5774 | a particular tracepoint, you may inspect those objects as if they were | |
5775 | in memory at that moment. However, because @value{GDBN} records these | |
5776 | values without interacting with you, it can do so quickly and | |
5777 | unobtrusively, hopefully not disturbing the program's behavior. | |
5778 | ||
5779 | The tracepoint facility is currently available only for remote | |
2c0069bb EZ |
5780 | targets. @xref{Targets}. In addition, your remote target must know how |
5781 | to collect trace data. This functionality is implemented in the remote | |
5782 | stub; however, none of the stubs distributed with @value{GDBN} support | |
5783 | tracepoints as of this writing. | |
b37052ae EZ |
5784 | |
5785 | This chapter describes the tracepoint commands and features. | |
5786 | ||
5787 | @menu | |
5788 | * Set Tracepoints:: | |
5789 | * Analyze Collected Data:: | |
5790 | * Tracepoint Variables:: | |
5791 | @end menu | |
5792 | ||
5793 | @node Set Tracepoints | |
5794 | @section Commands to Set Tracepoints | |
5795 | ||
5796 | Before running such a @dfn{trace experiment}, an arbitrary number of | |
5797 | tracepoints can be set. Like a breakpoint (@pxref{Set Breaks}), a | |
5798 | tracepoint has a number assigned to it by @value{GDBN}. Like with | |
5799 | breakpoints, tracepoint numbers are successive integers starting from | |
5800 | one. Many of the commands associated with tracepoints take the | |
5801 | tracepoint number as their argument, to identify which tracepoint to | |
5802 | work on. | |
5803 | ||
5804 | For each tracepoint, you can specify, in advance, some arbitrary set | |
5805 | of data that you want the target to collect in the trace buffer when | |
5806 | it hits that tracepoint. The collected data can include registers, | |
5807 | local variables, or global data. Later, you can use @value{GDBN} | |
5808 | commands to examine the values these data had at the time the | |
5809 | tracepoint was hit. | |
5810 | ||
5811 | This section describes commands to set tracepoints and associated | |
5812 | conditions and actions. | |
5813 | ||
5814 | @menu | |
5815 | * Create and Delete Tracepoints:: | |
5816 | * Enable and Disable Tracepoints:: | |
5817 | * Tracepoint Passcounts:: | |
5818 | * Tracepoint Actions:: | |
5819 | * Listing Tracepoints:: | |
5820 | * Starting and Stopping Trace Experiment:: | |
5821 | @end menu | |
5822 | ||
5823 | @node Create and Delete Tracepoints | |
5824 | @subsection Create and Delete Tracepoints | |
5825 | ||
5826 | @table @code | |
5827 | @cindex set tracepoint | |
5828 | @kindex trace | |
5829 | @item trace | |
5830 | The @code{trace} command is very similar to the @code{break} command. | |
5831 | Its argument can be a source line, a function name, or an address in | |
5832 | the target program. @xref{Set Breaks}. The @code{trace} command | |
5833 | defines a tracepoint, which is a point in the target program where the | |
5834 | debugger will briefly stop, collect some data, and then allow the | |
5835 | program to continue. Setting a tracepoint or changing its commands | |
5836 | doesn't take effect until the next @code{tstart} command; thus, you | |
5837 | cannot change the tracepoint attributes once a trace experiment is | |
5838 | running. | |
5839 | ||
5840 | Here are some examples of using the @code{trace} command: | |
5841 | ||
5842 | @smallexample | |
5843 | (@value{GDBP}) @b{trace foo.c:121} // a source file and line number | |
5844 | ||
5845 | (@value{GDBP}) @b{trace +2} // 2 lines forward | |
5846 | ||
5847 | (@value{GDBP}) @b{trace my_function} // first source line of function | |
5848 | ||
5849 | (@value{GDBP}) @b{trace *my_function} // EXACT start address of function | |
5850 | ||
5851 | (@value{GDBP}) @b{trace *0x2117c4} // an address | |
5852 | @end smallexample | |
5853 | ||
5854 | @noindent | |
5855 | You can abbreviate @code{trace} as @code{tr}. | |
5856 | ||
5857 | @vindex $tpnum | |
5858 | @cindex last tracepoint number | |
5859 | @cindex recent tracepoint number | |
5860 | @cindex tracepoint number | |
5861 | The convenience variable @code{$tpnum} records the tracepoint number | |
5862 | of the most recently set tracepoint. | |
5863 | ||
5864 | @kindex delete tracepoint | |
5865 | @cindex tracepoint deletion | |
5866 | @item delete tracepoint @r{[}@var{num}@r{]} | |
5867 | Permanently delete one or more tracepoints. With no argument, the | |
5868 | default is to delete all tracepoints. | |
5869 | ||
5870 | Examples: | |
5871 | ||
5872 | @smallexample | |
5873 | (@value{GDBP}) @b{delete trace 1 2 3} // remove three tracepoints | |
5874 | ||
5875 | (@value{GDBP}) @b{delete trace} // remove all tracepoints | |
5876 | @end smallexample | |
5877 | ||
5878 | @noindent | |
5879 | You can abbreviate this command as @code{del tr}. | |
5880 | @end table | |
5881 | ||
5882 | @node Enable and Disable Tracepoints | |
5883 | @subsection Enable and Disable Tracepoints | |
5884 | ||
5885 | @table @code | |
5886 | @kindex disable tracepoint | |
5887 | @item disable tracepoint @r{[}@var{num}@r{]} | |
5888 | Disable tracepoint @var{num}, or all tracepoints if no argument | |
5889 | @var{num} is given. A disabled tracepoint will have no effect during | |
5890 | the next trace experiment, but it is not forgotten. You can re-enable | |
5891 | a disabled tracepoint using the @code{enable tracepoint} command. | |
5892 | ||
5893 | @kindex enable tracepoint | |
5894 | @item enable tracepoint @r{[}@var{num}@r{]} | |
5895 | Enable tracepoint @var{num}, or all tracepoints. The enabled | |
5896 | tracepoints will become effective the next time a trace experiment is | |
5897 | run. | |
5898 | @end table | |
5899 | ||
5900 | @node Tracepoint Passcounts | |
5901 | @subsection Tracepoint Passcounts | |
5902 | ||
5903 | @table @code | |
5904 | @kindex passcount | |
5905 | @cindex tracepoint pass count | |
5906 | @item passcount @r{[}@var{n} @r{[}@var{num}@r{]]} | |
5907 | Set the @dfn{passcount} of a tracepoint. The passcount is a way to | |
5908 | automatically stop a trace experiment. If a tracepoint's passcount is | |
5909 | @var{n}, then the trace experiment will be automatically stopped on | |
5910 | the @var{n}'th time that tracepoint is hit. If the tracepoint number | |
5911 | @var{num} is not specified, the @code{passcount} command sets the | |
5912 | passcount of the most recently defined tracepoint. If no passcount is | |
5913 | given, the trace experiment will run until stopped explicitly by the | |
5914 | user. | |
5915 | ||
5916 | Examples: | |
5917 | ||
5918 | @smallexample | |
6826cf00 EZ |
5919 | (@value{GDBP}) @b{passcount 5 2} // Stop on the 5th execution of |
5920 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// tracepoint 2} | |
b37052ae EZ |
5921 | |
5922 | (@value{GDBP}) @b{passcount 12} // Stop on the 12th execution of the | |
6826cf00 | 5923 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// most recently defined tracepoint.} |
b37052ae EZ |
5924 | (@value{GDBP}) @b{trace foo} |
5925 | (@value{GDBP}) @b{pass 3} | |
5926 | (@value{GDBP}) @b{trace bar} | |
5927 | (@value{GDBP}) @b{pass 2} | |
5928 | (@value{GDBP}) @b{trace baz} | |
5929 | (@value{GDBP}) @b{pass 1} // Stop tracing when foo has been | |
6826cf00 EZ |
5930 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// executed 3 times OR when bar has} |
5931 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// been executed 2 times} | |
5932 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// OR when baz has been executed 1 time.} | |
b37052ae EZ |
5933 | @end smallexample |
5934 | @end table | |
5935 | ||
5936 | @node Tracepoint Actions | |
5937 | @subsection Tracepoint Action Lists | |
5938 | ||
5939 | @table @code | |
5940 | @kindex actions | |
5941 | @cindex tracepoint actions | |
5942 | @item actions @r{[}@var{num}@r{]} | |
5943 | This command will prompt for a list of actions to be taken when the | |
5944 | tracepoint is hit. If the tracepoint number @var{num} is not | |
5945 | specified, this command sets the actions for the one that was most | |
5946 | recently defined (so that you can define a tracepoint and then say | |
5947 | @code{actions} without bothering about its number). You specify the | |
5948 | actions themselves on the following lines, one action at a time, and | |
5949 | terminate the actions list with a line containing just @code{end}. So | |
5950 | far, the only defined actions are @code{collect} and | |
5951 | @code{while-stepping}. | |
5952 | ||
5953 | @cindex remove actions from a tracepoint | |
5954 | To remove all actions from a tracepoint, type @samp{actions @var{num}} | |
5955 | and follow it immediately with @samp{end}. | |
5956 | ||
5957 | @smallexample | |
5958 | (@value{GDBP}) @b{collect @var{data}} // collect some data | |
5959 | ||
6826cf00 | 5960 | (@value{GDBP}) @b{while-stepping 5} // single-step 5 times, collect data |
b37052ae | 5961 | |
6826cf00 | 5962 | (@value{GDBP}) @b{end} // signals the end of actions. |
b37052ae EZ |
5963 | @end smallexample |
5964 | ||
5965 | In the following example, the action list begins with @code{collect} | |
5966 | commands indicating the things to be collected when the tracepoint is | |
5967 | hit. Then, in order to single-step and collect additional data | |
5968 | following the tracepoint, a @code{while-stepping} command is used, | |
5969 | followed by the list of things to be collected while stepping. The | |
5970 | @code{while-stepping} command is terminated by its own separate | |
5971 | @code{end} command. Lastly, the action list is terminated by an | |
5972 | @code{end} command. | |
5973 | ||
5974 | @smallexample | |
5975 | (@value{GDBP}) @b{trace foo} | |
5976 | (@value{GDBP}) @b{actions} | |
5977 | Enter actions for tracepoint 1, one per line: | |
5978 | > collect bar,baz | |
5979 | > collect $regs | |
5980 | > while-stepping 12 | |
5981 | > collect $fp, $sp | |
5982 | > end | |
5983 | end | |
5984 | @end smallexample | |
5985 | ||
5986 | @kindex collect @r{(tracepoints)} | |
5987 | @item collect @var{expr1}, @var{expr2}, @dots{} | |
5988 | Collect values of the given expressions when the tracepoint is hit. | |
5989 | This command accepts a comma-separated list of any valid expressions. | |
5990 | In addition to global, static, or local variables, the following | |
5991 | special arguments are supported: | |
5992 | ||
5993 | @table @code | |
5994 | @item $regs | |
5995 | collect all registers | |
5996 | ||
5997 | @item $args | |
5998 | collect all function arguments | |
5999 | ||
6000 | @item $locals | |
6001 | collect all local variables. | |
6002 | @end table | |
6003 | ||
6004 | You can give several consecutive @code{collect} commands, each one | |
6005 | with a single argument, or one @code{collect} command with several | |
6006 | arguments separated by commas: the effect is the same. | |
6007 | ||
f5c37c66 EZ |
6008 | The command @code{info scope} (@pxref{Symbols, info scope}) is |
6009 | particularly useful for figuring out what data to collect. | |
6010 | ||
b37052ae EZ |
6011 | @kindex while-stepping @r{(tracepoints)} |
6012 | @item while-stepping @var{n} | |
6013 | Perform @var{n} single-step traces after the tracepoint, collecting | |
6014 | new data at each step. The @code{while-stepping} command is | |
6015 | followed by the list of what to collect while stepping (followed by | |
6016 | its own @code{end} command): | |
6017 | ||
6018 | @smallexample | |
6019 | > while-stepping 12 | |
6020 | > collect $regs, myglobal | |
6021 | > end | |
6022 | > | |
6023 | @end smallexample | |
6024 | ||
6025 | @noindent | |
6026 | You may abbreviate @code{while-stepping} as @code{ws} or | |
6027 | @code{stepping}. | |
6028 | @end table | |
6029 | ||
6030 | @node Listing Tracepoints | |
6031 | @subsection Listing Tracepoints | |
6032 | ||
6033 | @table @code | |
6034 | @kindex info tracepoints | |
6035 | @cindex information about tracepoints | |
6036 | @item info tracepoints @r{[}@var{num}@r{]} | |
6826cf00 EZ |
6037 | @c FIXME: Shouldn't there be an "at", "on", or "for" in the next |
6038 | @c sentence? - Brian Y., FSF office staff | |
b37052ae EZ |
6039 | Display information the tracepoint @var{num}. If you don't specify a |
6040 | tracepoint number displays information about all the tracepoints | |
6041 | defined so far. For each tracepoint, the following information is | |
6042 | shown: | |
6043 | ||
6044 | @itemize @bullet | |
6045 | @item | |
6046 | its number | |
6047 | @item | |
6048 | whether it is enabled or disabled | |
6049 | @item | |
6050 | its address | |
6051 | @item | |
6052 | its passcount as given by the @code{passcount @var{n}} command | |
6053 | @item | |
6054 | its step count as given by the @code{while-stepping @var{n}} command | |
6055 | @item | |
6056 | where in the source files is the tracepoint set | |
6057 | @item | |
6058 | its action list as given by the @code{actions} command | |
6059 | @end itemize | |
6060 | ||
6061 | @smallexample | |
6062 | (@value{GDBP}) @b{info trace} | |
6063 | Num Enb Address PassC StepC What | |
6064 | 1 y 0x002117c4 0 0 <gdb_asm> | |
6826cf00 EZ |
6065 | 2 y 0x0020dc64 0 0 in g_test at g_test.c:1375 |
6066 | 3 y 0x0020b1f4 0 0 in get_data at ../foo.c:41 | |
b37052ae EZ |
6067 | (@value{GDBP}) |
6068 | @end smallexample | |
6069 | ||
6070 | @noindent | |
6071 | This command can be abbreviated @code{info tp}. | |
6072 | @end table | |
6073 | ||
6074 | @node Starting and Stopping Trace Experiment | |
6075 | @subsection Starting and Stopping Trace Experiment | |
6076 | ||
6077 | @table @code | |
6078 | @kindex tstart | |
6079 | @cindex start a new trace experiment | |
6080 | @cindex collected data discarded | |
6081 | @item tstart | |
6082 | This command takes no arguments. It starts the trace experiment, and | |
6083 | begins collecting data. This has the side effect of discarding all | |
6084 | the data collected in the trace buffer during the previous trace | |
6085 | experiment. | |
6086 | ||
6087 | @kindex tstop | |
6088 | @cindex stop a running trace experiment | |
6089 | @item tstop | |
6090 | This command takes no arguments. It ends the trace experiment, and | |
6091 | stops collecting data. | |
6092 | ||
6093 | @strong{Note:} a trace experiment and data collection may stop | |
6094 | automatically if any tracepoint's passcount is reached | |
6095 | (@pxref{Tracepoint Passcounts}), or if the trace buffer becomes full. | |
6096 | ||
6097 | @kindex tstatus | |
6098 | @cindex status of trace data collection | |
6099 | @cindex trace experiment, status of | |
6100 | @item tstatus | |
6101 | This command displays the status of the current trace data | |
6102 | collection. | |
6103 | @end table | |
6104 | ||
6105 | Here is an example of the commands we described so far: | |
6106 | ||
6107 | @smallexample | |
6108 | (@value{GDBP}) @b{trace gdb_c_test} | |
6109 | (@value{GDBP}) @b{actions} | |
6110 | Enter actions for tracepoint #1, one per line. | |
6111 | > collect $regs,$locals,$args | |
6112 | > while-stepping 11 | |
6113 | > collect $regs | |
6114 | > end | |
6115 | > end | |
6116 | (@value{GDBP}) @b{tstart} | |
6117 | [time passes @dots{}] | |
6118 | (@value{GDBP}) @b{tstop} | |
6119 | @end smallexample | |
6120 | ||
6121 | ||
6122 | @node Analyze Collected Data | |
6123 | @section Using the collected data | |
6124 | ||
6125 | After the tracepoint experiment ends, you use @value{GDBN} commands | |
6126 | for examining the trace data. The basic idea is that each tracepoint | |
6127 | collects a trace @dfn{snapshot} every time it is hit and another | |
6128 | snapshot every time it single-steps. All these snapshots are | |
6129 | consecutively numbered from zero and go into a buffer, and you can | |
6130 | examine them later. The way you examine them is to @dfn{focus} on a | |
6131 | specific trace snapshot. When the remote stub is focused on a trace | |
6132 | snapshot, it will respond to all @value{GDBN} requests for memory and | |
6133 | registers by reading from the buffer which belongs to that snapshot, | |
6134 | rather than from @emph{real} memory or registers of the program being | |
6135 | debugged. This means that @strong{all} @value{GDBN} commands | |
6136 | (@code{print}, @code{info registers}, @code{backtrace}, etc.) will | |
6137 | behave as if we were currently debugging the program state as it was | |
6138 | when the tracepoint occurred. Any requests for data that are not in | |
6139 | the buffer will fail. | |
6140 | ||
6141 | @menu | |
6142 | * tfind:: How to select a trace snapshot | |
6143 | * tdump:: How to display all data for a snapshot | |
6144 | * save-tracepoints:: How to save tracepoints for a future run | |
6145 | @end menu | |
6146 | ||
6147 | @node tfind | |
6148 | @subsection @code{tfind @var{n}} | |
6149 | ||
6150 | @kindex tfind | |
6151 | @cindex select trace snapshot | |
6152 | @cindex find trace snapshot | |
6153 | The basic command for selecting a trace snapshot from the buffer is | |
6154 | @code{tfind @var{n}}, which finds trace snapshot number @var{n}, | |
6155 | counting from zero. If no argument @var{n} is given, the next | |
6156 | snapshot is selected. | |
6157 | ||
6158 | Here are the various forms of using the @code{tfind} command. | |
6159 | ||
6160 | @table @code | |
6161 | @item tfind start | |
6162 | Find the first snapshot in the buffer. This is a synonym for | |
6163 | @code{tfind 0} (since 0 is the number of the first snapshot). | |
6164 | ||
6165 | @item tfind none | |
6166 | Stop debugging trace snapshots, resume @emph{live} debugging. | |
6167 | ||
6168 | @item tfind end | |
6169 | Same as @samp{tfind none}. | |
6170 | ||
6171 | @item tfind | |
6172 | No argument means find the next trace snapshot. | |
6173 | ||
6174 | @item tfind - | |
6175 | Find the previous trace snapshot before the current one. This permits | |
6176 | retracing earlier steps. | |
6177 | ||
6178 | @item tfind tracepoint @var{num} | |
6179 | Find the next snapshot associated with tracepoint @var{num}. Search | |
6180 | proceeds forward from the last examined trace snapshot. If no | |
6181 | argument @var{num} is given, it means find the next snapshot collected | |
6182 | for the same tracepoint as the current snapshot. | |
6183 | ||
6184 | @item tfind pc @var{addr} | |
6185 | Find the next snapshot associated with the value @var{addr} of the | |
6186 | program counter. Search proceeds forward from the last examined trace | |
6187 | snapshot. If no argument @var{addr} is given, it means find the next | |
6188 | snapshot with the same value of PC as the current snapshot. | |
6189 | ||
6190 | @item tfind outside @var{addr1}, @var{addr2} | |
6191 | Find the next snapshot whose PC is outside the given range of | |
6192 | addresses. | |
6193 | ||
6194 | @item tfind range @var{addr1}, @var{addr2} | |
6195 | Find the next snapshot whose PC is between @var{addr1} and | |
6196 | @var{addr2}. @c FIXME: Is the range inclusive or exclusive? | |
6197 | ||
6198 | @item tfind line @r{[}@var{file}:@r{]}@var{n} | |
6199 | Find the next snapshot associated with the source line @var{n}. If | |
6200 | the optional argument @var{file} is given, refer to line @var{n} in | |
6201 | that source file. Search proceeds forward from the last examined | |
6202 | trace snapshot. If no argument @var{n} is given, it means find the | |
6203 | next line other than the one currently being examined; thus saying | |
6204 | @code{tfind line} repeatedly can appear to have the same effect as | |
6205 | stepping from line to line in a @emph{live} debugging session. | |
6206 | @end table | |
6207 | ||
6208 | The default arguments for the @code{tfind} commands are specifically | |
6209 | designed to make it easy to scan through the trace buffer. For | |
6210 | instance, @code{tfind} with no argument selects the next trace | |
6211 | snapshot, and @code{tfind -} with no argument selects the previous | |
6212 | trace snapshot. So, by giving one @code{tfind} command, and then | |
6213 | simply hitting @key{RET} repeatedly you can examine all the trace | |
6214 | snapshots in order. Or, by saying @code{tfind -} and then hitting | |
6215 | @key{RET} repeatedly you can examine the snapshots in reverse order. | |
6216 | The @code{tfind line} command with no argument selects the snapshot | |
6217 | for the next source line executed. The @code{tfind pc} command with | |
6218 | no argument selects the next snapshot with the same program counter | |
6219 | (PC) as the current frame. The @code{tfind tracepoint} command with | |
6220 | no argument selects the next trace snapshot collected by the same | |
6221 | tracepoint as the current one. | |
6222 | ||
6223 | In addition to letting you scan through the trace buffer manually, | |
6224 | these commands make it easy to construct @value{GDBN} scripts that | |
6225 | scan through the trace buffer and print out whatever collected data | |
6226 | you are interested in. Thus, if we want to examine the PC, FP, and SP | |
6227 | registers from each trace frame in the buffer, we can say this: | |
6228 | ||
6229 | @smallexample | |
6230 | (@value{GDBP}) @b{tfind start} | |
6231 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
6232 | > printf "Frame %d, PC = %08X, SP = %08X, FP = %08X\n", \ | |
6233 | $trace_frame, $pc, $sp, $fp | |
6234 | > tfind | |
6235 | > end | |
6236 | ||
6237 | Frame 0, PC = 0020DC64, SP = 0030BF3C, FP = 0030BF44 | |
6238 | Frame 1, PC = 0020DC6C, SP = 0030BF38, FP = 0030BF44 | |
6239 | Frame 2, PC = 0020DC70, SP = 0030BF34, FP = 0030BF44 | |
6240 | Frame 3, PC = 0020DC74, SP = 0030BF30, FP = 0030BF44 | |
6241 | Frame 4, PC = 0020DC78, SP = 0030BF2C, FP = 0030BF44 | |
6242 | Frame 5, PC = 0020DC7C, SP = 0030BF28, FP = 0030BF44 | |
6243 | Frame 6, PC = 0020DC80, SP = 0030BF24, FP = 0030BF44 | |
6244 | Frame 7, PC = 0020DC84, SP = 0030BF20, FP = 0030BF44 | |
6245 | Frame 8, PC = 0020DC88, SP = 0030BF1C, FP = 0030BF44 | |
6246 | Frame 9, PC = 0020DC8E, SP = 0030BF18, FP = 0030BF44 | |
6247 | Frame 10, PC = 00203F6C, SP = 0030BE3C, FP = 0030BF14 | |
6248 | @end smallexample | |
6249 | ||
6250 | Or, if we want to examine the variable @code{X} at each source line in | |
6251 | the buffer: | |
6252 | ||
6253 | @smallexample | |
6254 | (@value{GDBP}) @b{tfind start} | |
6255 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
6256 | > printf "Frame %d, X == %d\n", $trace_frame, X | |
6257 | > tfind line | |
6258 | > end | |
6259 | ||
6260 | Frame 0, X = 1 | |
6261 | Frame 7, X = 2 | |
6262 | Frame 13, X = 255 | |
6263 | @end smallexample | |
6264 | ||
6265 | @node tdump | |
6266 | @subsection @code{tdump} | |
6267 | @kindex tdump | |
6268 | @cindex dump all data collected at tracepoint | |
6269 | @cindex tracepoint data, display | |
6270 | ||
6271 | This command takes no arguments. It prints all the data collected at | |
6272 | the current trace snapshot. | |
6273 | ||
6274 | @smallexample | |
6275 | (@value{GDBP}) @b{trace 444} | |
6276 | (@value{GDBP}) @b{actions} | |
6277 | Enter actions for tracepoint #2, one per line: | |
6278 | > collect $regs, $locals, $args, gdb_long_test | |
6279 | > end | |
6280 | ||
6281 | (@value{GDBP}) @b{tstart} | |
6282 | ||
6283 | (@value{GDBP}) @b{tfind line 444} | |
6284 | #0 gdb_test (p1=0x11, p2=0x22, p3=0x33, p4=0x44, p5=0x55, p6=0x66) | |
6285 | at gdb_test.c:444 | |
6286 | 444 printp( "%s: arguments = 0x%X 0x%X 0x%X 0x%X 0x%X 0x%X\n", ) | |
6287 | ||
6288 | (@value{GDBP}) @b{tdump} | |
6289 | Data collected at tracepoint 2, trace frame 1: | |
6290 | d0 0xc4aa0085 -995491707 | |
6291 | d1 0x18 24 | |
6292 | d2 0x80 128 | |
6293 | d3 0x33 51 | |
6294 | d4 0x71aea3d 119204413 | |
6295 | d5 0x22 34 | |
6296 | d6 0xe0 224 | |
6297 | d7 0x380035 3670069 | |
6298 | a0 0x19e24a 1696330 | |
6299 | a1 0x3000668 50333288 | |
6300 | a2 0x100 256 | |
6301 | a3 0x322000 3284992 | |
6302 | a4 0x3000698 50333336 | |
6303 | a5 0x1ad3cc 1758156 | |
6304 | fp 0x30bf3c 0x30bf3c | |
6305 | sp 0x30bf34 0x30bf34 | |
6306 | ps 0x0 0 | |
6307 | pc 0x20b2c8 0x20b2c8 | |
6308 | fpcontrol 0x0 0 | |
6309 | fpstatus 0x0 0 | |
6310 | fpiaddr 0x0 0 | |
6311 | p = 0x20e5b4 "gdb-test" | |
6312 | p1 = (void *) 0x11 | |
6313 | p2 = (void *) 0x22 | |
6314 | p3 = (void *) 0x33 | |
6315 | p4 = (void *) 0x44 | |
6316 | p5 = (void *) 0x55 | |
6317 | p6 = (void *) 0x66 | |
6318 | gdb_long_test = 17 '\021' | |
6319 | ||
6320 | (@value{GDBP}) | |
6321 | @end smallexample | |
6322 | ||
6323 | @node save-tracepoints | |
6324 | @subsection @code{save-tracepoints @var{filename}} | |
6325 | @kindex save-tracepoints | |
6326 | @cindex save tracepoints for future sessions | |
6327 | ||
6328 | This command saves all current tracepoint definitions together with | |
6329 | their actions and passcounts, into a file @file{@var{filename}} | |
6330 | suitable for use in a later debugging session. To read the saved | |
6331 | tracepoint definitions, use the @code{source} command (@pxref{Command | |
6332 | Files}). | |
6333 | ||
6334 | @node Tracepoint Variables | |
6335 | @section Convenience Variables for Tracepoints | |
6336 | @cindex tracepoint variables | |
6337 | @cindex convenience variables for tracepoints | |
6338 | ||
6339 | @table @code | |
6340 | @vindex $trace_frame | |
6341 | @item (int) $trace_frame | |
6342 | The current trace snapshot (a.k.a.@: @dfn{frame}) number, or -1 if no | |
6343 | snapshot is selected. | |
6344 | ||
6345 | @vindex $tracepoint | |
6346 | @item (int) $tracepoint | |
6347 | The tracepoint for the current trace snapshot. | |
6348 | ||
6349 | @vindex $trace_line | |
6350 | @item (int) $trace_line | |
6351 | The line number for the current trace snapshot. | |
6352 | ||
6353 | @vindex $trace_file | |
6354 | @item (char []) $trace_file | |
6355 | The source file for the current trace snapshot. | |
6356 | ||
6357 | @vindex $trace_func | |
6358 | @item (char []) $trace_func | |
6359 | The name of the function containing @code{$tracepoint}. | |
6360 | @end table | |
6361 | ||
6362 | Note: @code{$trace_file} is not suitable for use in @code{printf}, | |
6363 | use @code{output} instead. | |
6364 | ||
6365 | Here's a simple example of using these convenience variables for | |
6366 | stepping through all the trace snapshots and printing some of their | |
6367 | data. | |
6368 | ||
6369 | @smallexample | |
6370 | (@value{GDBP}) @b{tfind start} | |
6371 | ||
6372 | (@value{GDBP}) @b{while $trace_frame != -1} | |
6373 | > output $trace_file | |
6374 | > printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint | |
6375 | > tfind | |
6376 | > end | |
6377 | @end smallexample | |
6378 | ||
df0cd8c5 JB |
6379 | @node Overlays |
6380 | @chapter Debugging Programs That Use Overlays | |
6381 | @cindex overlays | |
6382 | ||
6383 | If your program is too large to fit completely in your target system's | |
6384 | memory, you can sometimes use @dfn{overlays} to work around this | |
6385 | problem. @value{GDBN} provides some support for debugging programs that | |
6386 | use overlays. | |
6387 | ||
6388 | @menu | |
6389 | * How Overlays Work:: A general explanation of overlays. | |
6390 | * Overlay Commands:: Managing overlays in @value{GDBN}. | |
6391 | * Automatic Overlay Debugging:: @value{GDBN} can find out which overlays are | |
6392 | mapped by asking the inferior. | |
6393 | * Overlay Sample Program:: A sample program using overlays. | |
6394 | @end menu | |
6395 | ||
6396 | @node How Overlays Work | |
6397 | @section How Overlays Work | |
6398 | @cindex mapped overlays | |
6399 | @cindex unmapped overlays | |
6400 | @cindex load address, overlay's | |
6401 | @cindex mapped address | |
6402 | @cindex overlay area | |
6403 | ||
6404 | Suppose you have a computer whose instruction address space is only 64 | |
6405 | kilobytes long, but which has much more memory which can be accessed by | |
6406 | other means: special instructions, segment registers, or memory | |
6407 | management hardware, for example. Suppose further that you want to | |
6408 | adapt a program which is larger than 64 kilobytes to run on this system. | |
6409 | ||
6410 | One solution is to identify modules of your program which are relatively | |
6411 | independent, and need not call each other directly; call these modules | |
6412 | @dfn{overlays}. Separate the overlays from the main program, and place | |
6413 | their machine code in the larger memory. Place your main program in | |
6414 | instruction memory, but leave at least enough space there to hold the | |
6415 | largest overlay as well. | |
6416 | ||
6417 | Now, to call a function located in an overlay, you must first copy that | |
6418 | overlay's machine code from the large memory into the space set aside | |
6419 | for it in the instruction memory, and then jump to its entry point | |
6420 | there. | |
6421 | ||
6422 | @example | |
6423 | @group | |
6424 | Data Instruction Larger | |
6425 | Address Space Address Space Address Space | |
6426 | +-----------+ +-----------+ +-----------+ | |
6427 | | | | | | | | |
6428 | +-----------+ +-----------+ +-----------+<-- overlay 1 | |
6429 | | program | | main | | | load address | |
6430 | | variables | | program | | overlay 1 | | |
6431 | | and heap | | | ,---| | | |
6432 | +-----------+ | | | | | | |
6433 | | | +-----------+ | +-----------+ | |
6434 | +-----------+ | | | | | | |
6435 | mapped --->+-----------+ / +-----------+<-- overlay 2 | |
6436 | address | overlay | <-' | overlay 2 | load address | |
6437 | | area | <-----| | | |
6438 | | | <---. +-----------+ | |
6439 | | | | | | | |
6440 | +-----------+ | | | | |
6441 | | | | +-----------+<-- overlay 3 | |
6442 | +-----------+ `--| | load address | |
6443 | | overlay 3 | | |
6444 | | | | |
6445 | +-----------+ | |
6446 | | | | |
6447 | +-----------+ | |
6448 | ||
6449 | To map an overlay, copy its code from the larger address space | |
6450 | to the instruction address space. Since the overlays shown here | |
6451 | all use the same mapped address, only one may be mapped at a time. | |
6452 | @end group | |
6453 | @end example | |
6454 | ||
6455 | This diagram shows a system with separate data and instruction address | |
6456 | spaces. For a system with a single address space for data and | |
6457 | instructions, the diagram would be similar, except that the program | |
6458 | variables and heap would share an address space with the main program | |
6459 | and the overlay area. | |
6460 | ||
6461 | An overlay loaded into instruction memory and ready for use is called a | |
6462 | @dfn{mapped} overlay; its @dfn{mapped address} is its address in the | |
6463 | instruction memory. An overlay not present (or only partially present) | |
6464 | in instruction memory is called @dfn{unmapped}; its @dfn{load address} | |
6465 | is its address in the larger memory. The mapped address is also called | |
6466 | the @dfn{virtual memory address}, or @dfn{VMA}; the load address is also | |
6467 | called the @dfn{load memory address}, or @dfn{LMA}. | |
6468 | ||
6469 | Unfortunately, overlays are not a completely transparent way to adapt a | |
6470 | program to limited instruction memory. They introduce a new set of | |
6471 | global constraints you must keep in mind as you design your program: | |
6472 | ||
6473 | @itemize @bullet | |
6474 | ||
6475 | @item | |
6476 | Before calling or returning to a function in an overlay, your program | |
6477 | must make sure that overlay is actually mapped. Otherwise, the call or | |
6478 | return will transfer control to the right address, but in the wrong | |
6479 | overlay, and your program will probably crash. | |
6480 | ||
6481 | @item | |
6482 | If the process of mapping an overlay is expensive on your system, you | |
6483 | will need to choose your overlays carefully to minimize their effect on | |
6484 | your program's performance. | |
6485 | ||
6486 | @item | |
6487 | The executable file you load onto your system must contain each | |
6488 | overlay's instructions, appearing at the overlay's load address, not its | |
6489 | mapped address. However, each overlay's instructions must be relocated | |
6490 | and its symbols defined as if the overlay were at its mapped address. | |
6491 | You can use GNU linker scripts to specify different load and relocation | |
6492 | addresses for pieces of your program; see @ref{Overlay Description,,, | |
6493 | ld.info, Using ld: the GNU linker}. | |
6494 | ||
6495 | @item | |
6496 | The procedure for loading executable files onto your system must be able | |
6497 | to load their contents into the larger address space as well as the | |
6498 | instruction and data spaces. | |
6499 | ||
6500 | @end itemize | |
6501 | ||
6502 | The overlay system described above is rather simple, and could be | |
6503 | improved in many ways: | |
6504 | ||
6505 | @itemize @bullet | |
6506 | ||
6507 | @item | |
6508 | If your system has suitable bank switch registers or memory management | |
6509 | hardware, you could use those facilities to make an overlay's load area | |
6510 | contents simply appear at their mapped address in instruction space. | |
6511 | This would probably be faster than copying the overlay to its mapped | |
6512 | area in the usual way. | |
6513 | ||
6514 | @item | |
6515 | If your overlays are small enough, you could set aside more than one | |
6516 | overlay area, and have more than one overlay mapped at a time. | |
6517 | ||
6518 | @item | |
6519 | You can use overlays to manage data, as well as instructions. In | |
6520 | general, data overlays are even less transparent to your design than | |
6521 | code overlays: whereas code overlays only require care when you call or | |
6522 | return to functions, data overlays require care every time you access | |
6523 | the data. Also, if you change the contents of a data overlay, you | |
6524 | must copy its contents back out to its load address before you can copy a | |
6525 | different data overlay into the same mapped area. | |
6526 | ||
6527 | @end itemize | |
6528 | ||
6529 | ||
6530 | @node Overlay Commands | |
6531 | @section Overlay Commands | |
6532 | ||
6533 | To use @value{GDBN}'s overlay support, each overlay in your program must | |
6534 | correspond to a separate section of the executable file. The section's | |
6535 | virtual memory address and load memory address must be the overlay's | |
6536 | mapped and load addresses. Identifying overlays with sections allows | |
6537 | @value{GDBN} to determine the appropriate address of a function or | |
6538 | variable, depending on whether the overlay is mapped or not. | |
6539 | ||
6540 | @value{GDBN}'s overlay commands all start with the word @code{overlay}; | |
6541 | you can abbreviate this as @code{ov} or @code{ovly}. The commands are: | |
6542 | ||
6543 | @table @code | |
6544 | @item overlay off | |
6545 | @kindex overlay off | |
6546 | Disable @value{GDBN}'s overlay support. When overlay support is | |
6547 | disabled, @value{GDBN} assumes that all functions and variables are | |
6548 | always present at their mapped addresses. By default, @value{GDBN}'s | |
6549 | overlay support is disabled. | |
6550 | ||
6551 | @item overlay manual | |
6552 | @kindex overlay manual | |
6553 | @cindex manual overlay debugging | |
6554 | Enable @dfn{manual} overlay debugging. In this mode, @value{GDBN} | |
6555 | relies on you to tell it which overlays are mapped, and which are not, | |
6556 | using the @code{overlay map-overlay} and @code{overlay unmap-overlay} | |
6557 | commands described below. | |
6558 | ||
6559 | @item overlay map-overlay @var{overlay} | |
6560 | @itemx overlay map @var{overlay} | |
6561 | @kindex overlay map-overlay | |
6562 | @cindex map an overlay | |
6563 | Tell @value{GDBN} that @var{overlay} is now mapped; @var{overlay} must | |
6564 | be the name of the object file section containing the overlay. When an | |
6565 | overlay is mapped, @value{GDBN} assumes it can find the overlay's | |
6566 | functions and variables at their mapped addresses. @value{GDBN} assumes | |
6567 | that any other overlays whose mapped ranges overlap that of | |
6568 | @var{overlay} are now unmapped. | |
6569 | ||
6570 | @item overlay unmap-overlay @var{overlay} | |
6571 | @itemx overlay unmap @var{overlay} | |
6572 | @kindex overlay unmap-overlay | |
6573 | @cindex unmap an overlay | |
6574 | Tell @value{GDBN} that @var{overlay} is no longer mapped; @var{overlay} | |
6575 | must be the name of the object file section containing the overlay. | |
6576 | When an overlay is unmapped, @value{GDBN} assumes it can find the | |
6577 | overlay's functions and variables at their load addresses. | |
6578 | ||
6579 | @item overlay auto | |
6580 | @kindex overlay auto | |
6581 | Enable @dfn{automatic} overlay debugging. In this mode, @value{GDBN} | |
6582 | consults a data structure the overlay manager maintains in the inferior | |
6583 | to see which overlays are mapped. For details, see @ref{Automatic | |
6584 | Overlay Debugging}. | |
6585 | ||
6586 | @item overlay load-target | |
6587 | @itemx overlay load | |
6588 | @kindex overlay load-target | |
6589 | @cindex reloading the overlay table | |
6590 | Re-read the overlay table from the inferior. Normally, @value{GDBN} | |
6591 | re-reads the table @value{GDBN} automatically each time the inferior | |
6592 | stops, so this command should only be necessary if you have changed the | |
6593 | overlay mapping yourself using @value{GDBN}. This command is only | |
6594 | useful when using automatic overlay debugging. | |
6595 | ||
6596 | @item overlay list-overlays | |
6597 | @itemx overlay list | |
6598 | @cindex listing mapped overlays | |
6599 | Display a list of the overlays currently mapped, along with their mapped | |
6600 | addresses, load addresses, and sizes. | |
6601 | ||
6602 | @end table | |
6603 | ||
6604 | Normally, when @value{GDBN} prints a code address, it includes the name | |
6605 | of the function the address falls in: | |
6606 | ||
6607 | @example | |
6608 | (gdb) print main | |
6609 | $3 = @{int ()@} 0x11a0 <main> | |
6610 | @end example | |
6611 | @noindent | |
6612 | When overlay debugging is enabled, @value{GDBN} recognizes code in | |
6613 | unmapped overlays, and prints the names of unmapped functions with | |
6614 | asterisks around them. For example, if @code{foo} is a function in an | |
6615 | unmapped overlay, @value{GDBN} prints it this way: | |
6616 | ||
6617 | @example | |
6618 | (gdb) overlay list | |
6619 | No sections are mapped. | |
6620 | (gdb) print foo | |
6621 | $5 = @{int (int)@} 0x100000 <*foo*> | |
6622 | @end example | |
6623 | @noindent | |
6624 | When @code{foo}'s overlay is mapped, @value{GDBN} prints the function's | |
6625 | name normally: | |
6626 | ||
6627 | @example | |
6628 | (gdb) overlay list | |
6629 | Section .ov.foo.text, loaded at 0x100000 - 0x100034, | |
6630 | mapped at 0x1016 - 0x104a | |
6631 | (gdb) print foo | |
6632 | $6 = @{int (int)@} 0x1016 <foo> | |
6633 | @end example | |
6634 | ||
6635 | When overlay debugging is enabled, @value{GDBN} can find the correct | |
6636 | address for functions and variables in an overlay, whether or not the | |
6637 | overlay is mapped. This allows most @value{GDBN} commands, like | |
6638 | @code{break} and @code{disassemble}, to work normally, even on unmapped | |
6639 | code. However, @value{GDBN}'s breakpoint support has some limitations: | |
6640 | ||
6641 | @itemize @bullet | |
6642 | @item | |
6643 | @cindex breakpoints in overlays | |
6644 | @cindex overlays, setting breakpoints in | |
6645 | You can set breakpoints in functions in unmapped overlays, as long as | |
6646 | @value{GDBN} can write to the overlay at its load address. | |
6647 | @item | |
6648 | @value{GDBN} can not set hardware or simulator-based breakpoints in | |
6649 | unmapped overlays. However, if you set a breakpoint at the end of your | |
6650 | overlay manager (and tell @value{GDBN} which overlays are now mapped, if | |
6651 | you are using manual overlay management), @value{GDBN} will re-set its | |
6652 | breakpoints properly. | |
6653 | @end itemize | |
6654 | ||
6655 | ||
6656 | @node Automatic Overlay Debugging | |
6657 | @section Automatic Overlay Debugging | |
6658 | @cindex automatic overlay debugging | |
6659 | ||
6660 | @value{GDBN} can automatically track which overlays are mapped and which | |
6661 | are not, given some simple co-operation from the overlay manager in the | |
6662 | inferior. If you enable automatic overlay debugging with the | |
6663 | @code{overlay auto} command (@pxref{Overlay Commands}), @value{GDBN} | |
6664 | looks in the inferior's memory for certain variables describing the | |
6665 | current state of the overlays. | |
6666 | ||
6667 | Here are the variables your overlay manager must define to support | |
6668 | @value{GDBN}'s automatic overlay debugging: | |
6669 | ||
6670 | @table @asis | |
6671 | ||
6672 | @item @code{_ovly_table}: | |
6673 | This variable must be an array of the following structures: | |
6674 | ||
6675 | @example | |
6676 | struct | |
6677 | @{ | |
6678 | /* The overlay's mapped address. */ | |
6679 | unsigned long vma; | |
6680 | ||
6681 | /* The size of the overlay, in bytes. */ | |
6682 | unsigned long size; | |
6683 | ||
6684 | /* The overlay's load address. */ | |
6685 | unsigned long lma; | |
6686 | ||
6687 | /* Non-zero if the overlay is currently mapped; | |
6688 | zero otherwise. */ | |
6689 | unsigned long mapped; | |
6690 | @} | |
6691 | @end example | |
6692 | ||
6693 | @item @code{_novlys}: | |
6694 | This variable must be a four-byte signed integer, holding the total | |
6695 | number of elements in @code{_ovly_table}. | |
6696 | ||
6697 | @end table | |
6698 | ||
6699 | To decide whether a particular overlay is mapped or not, @value{GDBN} | |
6700 | looks for an entry in @w{@code{_ovly_table}} whose @code{vma} and | |
6701 | @code{lma} members equal the VMA and LMA of the overlay's section in the | |
6702 | executable file. When @value{GDBN} finds a matching entry, it consults | |
6703 | the entry's @code{mapped} member to determine whether the overlay is | |
6704 | currently mapped. | |
6705 | ||
6706 | ||
6707 | @node Overlay Sample Program | |
6708 | @section Overlay Sample Program | |
6709 | @cindex overlay example program | |
6710 | ||
6711 | When linking a program which uses overlays, you must place the overlays | |
6712 | at their load addresses, while relocating them to run at their mapped | |
6713 | addresses. To do this, you must write a linker script (@pxref{Overlay | |
6714 | Description,,, ld.info, Using ld: the GNU linker}). Unfortunately, | |
6715 | since linker scripts are specific to a particular host system, target | |
6716 | architecture, and target memory layout, this manual cannot provide | |
6717 | portable sample code demonstrating @value{GDBN}'s overlay support. | |
6718 | ||
6719 | However, the @value{GDBN} source distribution does contain an overlaid | |
6720 | program, with linker scripts for a few systems, as part of its test | |
6721 | suite. The program consists of the following files from | |
6722 | @file{gdb/testsuite/gdb.base}: | |
6723 | ||
6724 | @table @file | |
6725 | @item overlays.c | |
6726 | The main program file. | |
6727 | @item ovlymgr.c | |
6728 | A simple overlay manager, used by @file{overlays.c}. | |
6729 | @item foo.c | |
6730 | @itemx bar.c | |
6731 | @itemx baz.c | |
6732 | @itemx grbx.c | |
6733 | Overlay modules, loaded and used by @file{overlays.c}. | |
6734 | @item d10v.ld | |
6735 | @itemx m32r.ld | |
6736 | Linker scripts for linking the test program on the @code{d10v-elf} | |
6737 | and @code{m32r-elf} targets. | |
6738 | @end table | |
6739 | ||
6740 | You can build the test program using the @code{d10v-elf} GCC | |
6741 | cross-compiler like this: | |
6742 | ||
6743 | @example | |
6744 | $ d10v-elf-gcc -g -c overlays.c | |
6745 | $ d10v-elf-gcc -g -c ovlymgr.c | |
6746 | $ d10v-elf-gcc -g -c foo.c | |
6747 | $ d10v-elf-gcc -g -c bar.c | |
6748 | $ d10v-elf-gcc -g -c baz.c | |
6749 | $ d10v-elf-gcc -g -c grbx.c | |
6750 | $ d10v-elf-gcc -g overlays.o ovlymgr.o foo.o bar.o \ | |
6751 | baz.o grbx.o -Wl,-Td10v.ld -o overlays | |
6752 | @end example | |
6753 | ||
6754 | The build process is identical for any other architecture, except that | |
6755 | you must substitute the appropriate compiler and linker script for the | |
6756 | target system for @code{d10v-elf-gcc} and @code{d10v.ld}. | |
6757 | ||
6758 | ||
6d2ebf8b | 6759 | @node Languages |
c906108c SS |
6760 | @chapter Using @value{GDBN} with Different Languages |
6761 | @cindex languages | |
6762 | ||
c906108c SS |
6763 | Although programming languages generally have common aspects, they are |
6764 | rarely expressed in the same manner. For instance, in ANSI C, | |
6765 | dereferencing a pointer @code{p} is accomplished by @code{*p}, but in | |
6766 | Modula-2, it is accomplished by @code{p^}. Values can also be | |
5d161b24 | 6767 | represented (and displayed) differently. Hex numbers in C appear as |
c906108c | 6768 | @samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}. |
c906108c SS |
6769 | |
6770 | @cindex working language | |
6771 | Language-specific information is built into @value{GDBN} for some languages, | |
6772 | allowing you to express operations like the above in your program's | |
6773 | native language, and allowing @value{GDBN} to output values in a manner | |
6774 | consistent with the syntax of your program's native language. The | |
6775 | language you use to build expressions is called the @dfn{working | |
6776 | language}. | |
6777 | ||
6778 | @menu | |
6779 | * Setting:: Switching between source languages | |
6780 | * Show:: Displaying the language | |
c906108c | 6781 | * Checks:: Type and range checks |
c906108c SS |
6782 | * Support:: Supported languages |
6783 | @end menu | |
6784 | ||
6d2ebf8b | 6785 | @node Setting |
c906108c SS |
6786 | @section Switching between source languages |
6787 | ||
6788 | There are two ways to control the working language---either have @value{GDBN} | |
6789 | set it automatically, or select it manually yourself. You can use the | |
6790 | @code{set language} command for either purpose. On startup, @value{GDBN} | |
6791 | defaults to setting the language automatically. The working language is | |
6792 | used to determine how expressions you type are interpreted, how values | |
6793 | are printed, etc. | |
6794 | ||
6795 | In addition to the working language, every source file that | |
6796 | @value{GDBN} knows about has its own working language. For some object | |
6797 | file formats, the compiler might indicate which language a particular | |
6798 | source file is in. However, most of the time @value{GDBN} infers the | |
6799 | language from the name of the file. The language of a source file | |
b37052ae | 6800 | controls whether C@t{++} names are demangled---this way @code{backtrace} can |
c906108c | 6801 | show each frame appropriately for its own language. There is no way to |
d4f3574e SS |
6802 | set the language of a source file from within @value{GDBN}, but you can |
6803 | set the language associated with a filename extension. @xref{Show, , | |
6804 | Displaying the language}. | |
c906108c SS |
6805 | |
6806 | This is most commonly a problem when you use a program, such | |
5d161b24 | 6807 | as @code{cfront} or @code{f2c}, that generates C but is written in |
c906108c SS |
6808 | another language. In that case, make the |
6809 | program use @code{#line} directives in its C output; that way | |
6810 | @value{GDBN} will know the correct language of the source code of the original | |
6811 | program, and will display that source code, not the generated C code. | |
6812 | ||
6813 | @menu | |
6814 | * Filenames:: Filename extensions and languages. | |
6815 | * Manually:: Setting the working language manually | |
6816 | * Automatically:: Having @value{GDBN} infer the source language | |
6817 | @end menu | |
6818 | ||
6d2ebf8b | 6819 | @node Filenames |
c906108c SS |
6820 | @subsection List of filename extensions and languages |
6821 | ||
6822 | If a source file name ends in one of the following extensions, then | |
6823 | @value{GDBN} infers that its language is the one indicated. | |
6824 | ||
6825 | @table @file | |
6826 | ||
6827 | @item .c | |
6828 | C source file | |
6829 | ||
6830 | @item .C | |
6831 | @itemx .cc | |
6832 | @itemx .cp | |
6833 | @itemx .cpp | |
6834 | @itemx .cxx | |
6835 | @itemx .c++ | |
b37052ae | 6836 | C@t{++} source file |
c906108c SS |
6837 | |
6838 | @item .f | |
6839 | @itemx .F | |
6840 | Fortran source file | |
6841 | ||
c906108c SS |
6842 | @item .ch |
6843 | @itemx .c186 | |
6844 | @itemx .c286 | |
96a2c332 | 6845 | CHILL source file |
c906108c | 6846 | |
c906108c SS |
6847 | @item .mod |
6848 | Modula-2 source file | |
c906108c SS |
6849 | |
6850 | @item .s | |
6851 | @itemx .S | |
6852 | Assembler source file. This actually behaves almost like C, but | |
6853 | @value{GDBN} does not skip over function prologues when stepping. | |
6854 | @end table | |
6855 | ||
6856 | In addition, you may set the language associated with a filename | |
6857 | extension. @xref{Show, , Displaying the language}. | |
6858 | ||
6d2ebf8b | 6859 | @node Manually |
c906108c SS |
6860 | @subsection Setting the working language |
6861 | ||
6862 | If you allow @value{GDBN} to set the language automatically, | |
6863 | expressions are interpreted the same way in your debugging session and | |
6864 | your program. | |
6865 | ||
6866 | @kindex set language | |
6867 | If you wish, you may set the language manually. To do this, issue the | |
6868 | command @samp{set language @var{lang}}, where @var{lang} is the name of | |
5d161b24 | 6869 | a language, such as |
c906108c | 6870 | @code{c} or @code{modula-2}. |
c906108c SS |
6871 | For a list of the supported languages, type @samp{set language}. |
6872 | ||
c906108c SS |
6873 | Setting the language manually prevents @value{GDBN} from updating the working |
6874 | language automatically. This can lead to confusion if you try | |
6875 | to debug a program when the working language is not the same as the | |
6876 | source language, when an expression is acceptable to both | |
6877 | languages---but means different things. For instance, if the current | |
6878 | source file were written in C, and @value{GDBN} was parsing Modula-2, a | |
6879 | command such as: | |
6880 | ||
6881 | @example | |
6882 | print a = b + c | |
6883 | @end example | |
6884 | ||
6885 | @noindent | |
6886 | might not have the effect you intended. In C, this means to add | |
6887 | @code{b} and @code{c} and place the result in @code{a}. The result | |
6888 | printed would be the value of @code{a}. In Modula-2, this means to compare | |
6889 | @code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value. | |
c906108c | 6890 | |
6d2ebf8b | 6891 | @node Automatically |
c906108c SS |
6892 | @subsection Having @value{GDBN} infer the source language |
6893 | ||
6894 | To have @value{GDBN} set the working language automatically, use | |
6895 | @samp{set language local} or @samp{set language auto}. @value{GDBN} | |
6896 | then infers the working language. That is, when your program stops in a | |
6897 | frame (usually by encountering a breakpoint), @value{GDBN} sets the | |
6898 | working language to the language recorded for the function in that | |
6899 | frame. If the language for a frame is unknown (that is, if the function | |
6900 | or block corresponding to the frame was defined in a source file that | |
6901 | does not have a recognized extension), the current working language is | |
6902 | not changed, and @value{GDBN} issues a warning. | |
6903 | ||
6904 | This may not seem necessary for most programs, which are written | |
6905 | entirely in one source language. However, program modules and libraries | |
6906 | written in one source language can be used by a main program written in | |
6907 | a different source language. Using @samp{set language auto} in this | |
6908 | case frees you from having to set the working language manually. | |
6909 | ||
6d2ebf8b | 6910 | @node Show |
c906108c | 6911 | @section Displaying the language |
c906108c SS |
6912 | |
6913 | The following commands help you find out which language is the | |
6914 | working language, and also what language source files were written in. | |
6915 | ||
6916 | @kindex show language | |
d4f3574e SS |
6917 | @kindex info frame@r{, show the source language} |
6918 | @kindex info source@r{, show the source language} | |
c906108c SS |
6919 | @table @code |
6920 | @item show language | |
6921 | Display the current working language. This is the | |
6922 | language you can use with commands such as @code{print} to | |
6923 | build and compute expressions that may involve variables in your program. | |
6924 | ||
6925 | @item info frame | |
5d161b24 | 6926 | Display the source language for this frame. This language becomes the |
c906108c | 6927 | working language if you use an identifier from this frame. |
5d161b24 | 6928 | @xref{Frame Info, ,Information about a frame}, to identify the other |
c906108c SS |
6929 | information listed here. |
6930 | ||
6931 | @item info source | |
6932 | Display the source language of this source file. | |
5d161b24 | 6933 | @xref{Symbols, ,Examining the Symbol Table}, to identify the other |
c906108c SS |
6934 | information listed here. |
6935 | @end table | |
6936 | ||
6937 | In unusual circumstances, you may have source files with extensions | |
6938 | not in the standard list. You can then set the extension associated | |
6939 | with a language explicitly: | |
6940 | ||
6941 | @kindex set extension-language | |
6942 | @kindex info extensions | |
6943 | @table @code | |
6944 | @item set extension-language @var{.ext} @var{language} | |
6945 | Set source files with extension @var{.ext} to be assumed to be in | |
6946 | the source language @var{language}. | |
6947 | ||
6948 | @item info extensions | |
6949 | List all the filename extensions and the associated languages. | |
6950 | @end table | |
6951 | ||
6d2ebf8b | 6952 | @node Checks |
c906108c SS |
6953 | @section Type and range checking |
6954 | ||
6955 | @quotation | |
6956 | @emph{Warning:} In this release, the @value{GDBN} commands for type and range | |
6957 | checking are included, but they do not yet have any effect. This | |
6958 | section documents the intended facilities. | |
6959 | @end quotation | |
6960 | @c FIXME remove warning when type/range code added | |
6961 | ||
6962 | Some languages are designed to guard you against making seemingly common | |
6963 | errors through a series of compile- and run-time checks. These include | |
6964 | checking the type of arguments to functions and operators, and making | |
6965 | sure mathematical overflows are caught at run time. Checks such as | |
6966 | these help to ensure a program's correctness once it has been compiled | |
6967 | by eliminating type mismatches, and providing active checks for range | |
6968 | errors when your program is running. | |
6969 | ||
6970 | @value{GDBN} can check for conditions like the above if you wish. | |
6971 | Although @value{GDBN} does not check the statements in your program, it | |
6972 | can check expressions entered directly into @value{GDBN} for evaluation via | |
6973 | the @code{print} command, for example. As with the working language, | |
6974 | @value{GDBN} can also decide whether or not to check automatically based on | |
6975 | your program's source language. @xref{Support, ,Supported languages}, | |
6976 | for the default settings of supported languages. | |
6977 | ||
6978 | @menu | |
6979 | * Type Checking:: An overview of type checking | |
6980 | * Range Checking:: An overview of range checking | |
6981 | @end menu | |
6982 | ||
6983 | @cindex type checking | |
6984 | @cindex checks, type | |
6d2ebf8b | 6985 | @node Type Checking |
c906108c SS |
6986 | @subsection An overview of type checking |
6987 | ||
6988 | Some languages, such as Modula-2, are strongly typed, meaning that the | |
6989 | arguments to operators and functions have to be of the correct type, | |
6990 | otherwise an error occurs. These checks prevent type mismatch | |
6991 | errors from ever causing any run-time problems. For example, | |
6992 | ||
6993 | @smallexample | |
6994 | 1 + 2 @result{} 3 | |
6995 | @exdent but | |
6996 | @error{} 1 + 2.3 | |
6997 | @end smallexample | |
6998 | ||
6999 | The second example fails because the @code{CARDINAL} 1 is not | |
7000 | type-compatible with the @code{REAL} 2.3. | |
7001 | ||
5d161b24 DB |
7002 | For the expressions you use in @value{GDBN} commands, you can tell the |
7003 | @value{GDBN} type checker to skip checking; | |
7004 | to treat any mismatches as errors and abandon the expression; | |
7005 | or to only issue warnings when type mismatches occur, | |
c906108c SS |
7006 | but evaluate the expression anyway. When you choose the last of |
7007 | these, @value{GDBN} evaluates expressions like the second example above, but | |
7008 | also issues a warning. | |
7009 | ||
5d161b24 DB |
7010 | Even if you turn type checking off, there may be other reasons |
7011 | related to type that prevent @value{GDBN} from evaluating an expression. | |
7012 | For instance, @value{GDBN} does not know how to add an @code{int} and | |
7013 | a @code{struct foo}. These particular type errors have nothing to do | |
7014 | with the language in use, and usually arise from expressions, such as | |
c906108c SS |
7015 | the one described above, which make little sense to evaluate anyway. |
7016 | ||
7017 | Each language defines to what degree it is strict about type. For | |
7018 | instance, both Modula-2 and C require the arguments to arithmetical | |
7019 | operators to be numbers. In C, enumerated types and pointers can be | |
7020 | represented as numbers, so that they are valid arguments to mathematical | |
7021 | operators. @xref{Support, ,Supported languages}, for further | |
7022 | details on specific languages. | |
7023 | ||
7024 | @value{GDBN} provides some additional commands for controlling the type checker: | |
7025 | ||
d4f3574e | 7026 | @kindex set check@r{, type} |
c906108c SS |
7027 | @kindex set check type |
7028 | @kindex show check type | |
7029 | @table @code | |
7030 | @item set check type auto | |
7031 | Set type checking on or off based on the current working language. | |
7032 | @xref{Support, ,Supported languages}, for the default settings for | |
7033 | each language. | |
7034 | ||
7035 | @item set check type on | |
7036 | @itemx set check type off | |
7037 | Set type checking on or off, overriding the default setting for the | |
7038 | current working language. Issue a warning if the setting does not | |
7039 | match the language default. If any type mismatches occur in | |
d4f3574e | 7040 | evaluating an expression while type checking is on, @value{GDBN} prints a |
c906108c SS |
7041 | message and aborts evaluation of the expression. |
7042 | ||
7043 | @item set check type warn | |
7044 | Cause the type checker to issue warnings, but to always attempt to | |
7045 | evaluate the expression. Evaluating the expression may still | |
7046 | be impossible for other reasons. For example, @value{GDBN} cannot add | |
7047 | numbers and structures. | |
7048 | ||
7049 | @item show type | |
5d161b24 | 7050 | Show the current setting of the type checker, and whether or not @value{GDBN} |
c906108c SS |
7051 | is setting it automatically. |
7052 | @end table | |
7053 | ||
7054 | @cindex range checking | |
7055 | @cindex checks, range | |
6d2ebf8b | 7056 | @node Range Checking |
c906108c SS |
7057 | @subsection An overview of range checking |
7058 | ||
7059 | In some languages (such as Modula-2), it is an error to exceed the | |
7060 | bounds of a type; this is enforced with run-time checks. Such range | |
7061 | checking is meant to ensure program correctness by making sure | |
7062 | computations do not overflow, or indices on an array element access do | |
7063 | not exceed the bounds of the array. | |
7064 | ||
7065 | For expressions you use in @value{GDBN} commands, you can tell | |
7066 | @value{GDBN} to treat range errors in one of three ways: ignore them, | |
7067 | always treat them as errors and abandon the expression, or issue | |
7068 | warnings but evaluate the expression anyway. | |
7069 | ||
7070 | A range error can result from numerical overflow, from exceeding an | |
7071 | array index bound, or when you type a constant that is not a member | |
7072 | of any type. Some languages, however, do not treat overflows as an | |
7073 | error. In many implementations of C, mathematical overflow causes the | |
7074 | result to ``wrap around'' to lower values---for example, if @var{m} is | |
7075 | the largest integer value, and @var{s} is the smallest, then | |
7076 | ||
7077 | @example | |
7078 | @var{m} + 1 @result{} @var{s} | |
7079 | @end example | |
7080 | ||
7081 | This, too, is specific to individual languages, and in some cases | |
7082 | specific to individual compilers or machines. @xref{Support, , | |
7083 | Supported languages}, for further details on specific languages. | |
7084 | ||
7085 | @value{GDBN} provides some additional commands for controlling the range checker: | |
7086 | ||
d4f3574e | 7087 | @kindex set check@r{, range} |
c906108c SS |
7088 | @kindex set check range |
7089 | @kindex show check range | |
7090 | @table @code | |
7091 | @item set check range auto | |
7092 | Set range checking on or off based on the current working language. | |
7093 | @xref{Support, ,Supported languages}, for the default settings for | |
7094 | each language. | |
7095 | ||
7096 | @item set check range on | |
7097 | @itemx set check range off | |
7098 | Set range checking on or off, overriding the default setting for the | |
7099 | current working language. A warning is issued if the setting does not | |
c3f6f71d JM |
7100 | match the language default. If a range error occurs and range checking is on, |
7101 | then a message is printed and evaluation of the expression is aborted. | |
c906108c SS |
7102 | |
7103 | @item set check range warn | |
7104 | Output messages when the @value{GDBN} range checker detects a range error, | |
7105 | but attempt to evaluate the expression anyway. Evaluating the | |
7106 | expression may still be impossible for other reasons, such as accessing | |
7107 | memory that the process does not own (a typical example from many Unix | |
7108 | systems). | |
7109 | ||
7110 | @item show range | |
7111 | Show the current setting of the range checker, and whether or not it is | |
7112 | being set automatically by @value{GDBN}. | |
7113 | @end table | |
c906108c | 7114 | |
6d2ebf8b | 7115 | @node Support |
c906108c | 7116 | @section Supported languages |
c906108c | 7117 | |
b37052ae | 7118 | @value{GDBN} supports C, C@t{++}, Fortran, Java, Chill, assembly, and Modula-2. |
cce74817 | 7119 | @c This is false ... |
c906108c SS |
7120 | Some @value{GDBN} features may be used in expressions regardless of the |
7121 | language you use: the @value{GDBN} @code{@@} and @code{::} operators, | |
7122 | and the @samp{@{type@}addr} construct (@pxref{Expressions, | |
7123 | ,Expressions}) can be used with the constructs of any supported | |
7124 | language. | |
7125 | ||
7126 | The following sections detail to what degree each source language is | |
7127 | supported by @value{GDBN}. These sections are not meant to be language | |
7128 | tutorials or references, but serve only as a reference guide to what the | |
7129 | @value{GDBN} expression parser accepts, and what input and output | |
7130 | formats should look like for different languages. There are many good | |
7131 | books written on each of these languages; please look to these for a | |
7132 | language reference or tutorial. | |
7133 | ||
c906108c | 7134 | @menu |
b37052ae | 7135 | * C:: C and C@t{++} |
cce74817 | 7136 | * Modula-2:: Modula-2 |
104c1213 | 7137 | * Chill:: Chill |
c906108c SS |
7138 | @end menu |
7139 | ||
6d2ebf8b | 7140 | @node C |
b37052ae | 7141 | @subsection C and C@t{++} |
7a292a7a | 7142 | |
b37052ae EZ |
7143 | @cindex C and C@t{++} |
7144 | @cindex expressions in C or C@t{++} | |
c906108c | 7145 | |
b37052ae | 7146 | Since C and C@t{++} are so closely related, many features of @value{GDBN} apply |
c906108c SS |
7147 | to both languages. Whenever this is the case, we discuss those languages |
7148 | together. | |
7149 | ||
41afff9a EZ |
7150 | @cindex C@t{++} |
7151 | @cindex @code{g++}, @sc{gnu} C@t{++} compiler | |
b37052ae EZ |
7152 | @cindex @sc{gnu} C@t{++} |
7153 | The C@t{++} debugging facilities are jointly implemented by the C@t{++} | |
7154 | compiler and @value{GDBN}. Therefore, to debug your C@t{++} code | |
7155 | effectively, you must compile your C@t{++} programs with a supported | |
7156 | C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++} | |
c906108c SS |
7157 | compiler (@code{aCC}). |
7158 | ||
b37052ae | 7159 | For best results when using @sc{gnu} C@t{++}, use the stabs debugging |
c906108c SS |
7160 | format. You can select that format explicitly with the @code{g++} |
7161 | command-line options @samp{-gstabs} or @samp{-gstabs+}. See | |
7162 | @ref{Debugging Options,,Options for Debugging Your Program or @sc{gnu} | |
7163 | CC, gcc.info, Using @sc{gnu} CC}, for more information. | |
c906108c | 7164 | |
c906108c | 7165 | @menu |
b37052ae EZ |
7166 | * C Operators:: C and C@t{++} operators |
7167 | * C Constants:: C and C@t{++} constants | |
7168 | * C plus plus expressions:: C@t{++} expressions | |
7169 | * C Defaults:: Default settings for C and C@t{++} | |
7170 | * C Checks:: C and C@t{++} type and range checks | |
c906108c | 7171 | * Debugging C:: @value{GDBN} and C |
b37052ae | 7172 | * Debugging C plus plus:: @value{GDBN} features for C@t{++} |
c906108c | 7173 | @end menu |
c906108c | 7174 | |
6d2ebf8b | 7175 | @node C Operators |
b37052ae | 7176 | @subsubsection C and C@t{++} operators |
7a292a7a | 7177 | |
b37052ae | 7178 | @cindex C and C@t{++} operators |
c906108c SS |
7179 | |
7180 | Operators must be defined on values of specific types. For instance, | |
7181 | @code{+} is defined on numbers, but not on structures. Operators are | |
5d161b24 | 7182 | often defined on groups of types. |
c906108c | 7183 | |
b37052ae | 7184 | For the purposes of C and C@t{++}, the following definitions hold: |
c906108c SS |
7185 | |
7186 | @itemize @bullet | |
53a5351d | 7187 | |
c906108c | 7188 | @item |
c906108c | 7189 | @emph{Integral types} include @code{int} with any of its storage-class |
b37052ae | 7190 | specifiers; @code{char}; @code{enum}; and, for C@t{++}, @code{bool}. |
c906108c SS |
7191 | |
7192 | @item | |
d4f3574e SS |
7193 | @emph{Floating-point types} include @code{float}, @code{double}, and |
7194 | @code{long double} (if supported by the target platform). | |
c906108c SS |
7195 | |
7196 | @item | |
53a5351d | 7197 | @emph{Pointer types} include all types defined as @code{(@var{type} *)}. |
c906108c SS |
7198 | |
7199 | @item | |
7200 | @emph{Scalar types} include all of the above. | |
53a5351d | 7201 | |
c906108c SS |
7202 | @end itemize |
7203 | ||
7204 | @noindent | |
7205 | The following operators are supported. They are listed here | |
7206 | in order of increasing precedence: | |
7207 | ||
7208 | @table @code | |
7209 | @item , | |
7210 | The comma or sequencing operator. Expressions in a comma-separated list | |
7211 | are evaluated from left to right, with the result of the entire | |
7212 | expression being the last expression evaluated. | |
7213 | ||
7214 | @item = | |
7215 | Assignment. The value of an assignment expression is the value | |
7216 | assigned. Defined on scalar types. | |
7217 | ||
7218 | @item @var{op}= | |
7219 | Used in an expression of the form @w{@code{@var{a} @var{op}= @var{b}}}, | |
7220 | and translated to @w{@code{@var{a} = @var{a op b}}}. | |
d4f3574e | 7221 | @w{@code{@var{op}=}} and @code{=} have the same precedence. |
c906108c SS |
7222 | @var{op} is any one of the operators @code{|}, @code{^}, @code{&}, |
7223 | @code{<<}, @code{>>}, @code{+}, @code{-}, @code{*}, @code{/}, @code{%}. | |
7224 | ||
7225 | @item ?: | |
7226 | The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought | |
7227 | of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an | |
7228 | integral type. | |
7229 | ||
7230 | @item || | |
7231 | Logical @sc{or}. Defined on integral types. | |
7232 | ||
7233 | @item && | |
7234 | Logical @sc{and}. Defined on integral types. | |
7235 | ||
7236 | @item | | |
7237 | Bitwise @sc{or}. Defined on integral types. | |
7238 | ||
7239 | @item ^ | |
7240 | Bitwise exclusive-@sc{or}. Defined on integral types. | |
7241 | ||
7242 | @item & | |
7243 | Bitwise @sc{and}. Defined on integral types. | |
7244 | ||
7245 | @item ==@r{, }!= | |
7246 | Equality and inequality. Defined on scalar types. The value of these | |
7247 | expressions is 0 for false and non-zero for true. | |
7248 | ||
7249 | @item <@r{, }>@r{, }<=@r{, }>= | |
7250 | Less than, greater than, less than or equal, greater than or equal. | |
7251 | Defined on scalar types. The value of these expressions is 0 for false | |
7252 | and non-zero for true. | |
7253 | ||
7254 | @item <<@r{, }>> | |
7255 | left shift, and right shift. Defined on integral types. | |
7256 | ||
7257 | @item @@ | |
7258 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
7259 | ||
7260 | @item +@r{, }- | |
7261 | Addition and subtraction. Defined on integral types, floating-point types and | |
7262 | pointer types. | |
7263 | ||
7264 | @item *@r{, }/@r{, }% | |
7265 | Multiplication, division, and modulus. Multiplication and division are | |
7266 | defined on integral and floating-point types. Modulus is defined on | |
7267 | integral types. | |
7268 | ||
7269 | @item ++@r{, }-- | |
7270 | Increment and decrement. When appearing before a variable, the | |
7271 | operation is performed before the variable is used in an expression; | |
7272 | when appearing after it, the variable's value is used before the | |
7273 | operation takes place. | |
7274 | ||
7275 | @item * | |
7276 | Pointer dereferencing. Defined on pointer types. Same precedence as | |
7277 | @code{++}. | |
7278 | ||
7279 | @item & | |
7280 | Address operator. Defined on variables. Same precedence as @code{++}. | |
7281 | ||
b37052ae EZ |
7282 | For debugging C@t{++}, @value{GDBN} implements a use of @samp{&} beyond what is |
7283 | allowed in the C@t{++} language itself: you can use @samp{&(&@var{ref})} | |
c906108c | 7284 | (or, if you prefer, simply @samp{&&@var{ref}}) to examine the address |
b37052ae | 7285 | where a C@t{++} reference variable (declared with @samp{&@var{ref}}) is |
c906108c | 7286 | stored. |
c906108c SS |
7287 | |
7288 | @item - | |
7289 | Negative. Defined on integral and floating-point types. Same | |
7290 | precedence as @code{++}. | |
7291 | ||
7292 | @item ! | |
7293 | Logical negation. Defined on integral types. Same precedence as | |
7294 | @code{++}. | |
7295 | ||
7296 | @item ~ | |
7297 | Bitwise complement operator. Defined on integral types. Same precedence as | |
7298 | @code{++}. | |
7299 | ||
7300 | ||
7301 | @item .@r{, }-> | |
7302 | Structure member, and pointer-to-structure member. For convenience, | |
7303 | @value{GDBN} regards the two as equivalent, choosing whether to dereference a | |
7304 | pointer based on the stored type information. | |
7305 | Defined on @code{struct} and @code{union} data. | |
7306 | ||
c906108c SS |
7307 | @item .*@r{, }->* |
7308 | Dereferences of pointers to members. | |
c906108c SS |
7309 | |
7310 | @item [] | |
7311 | Array indexing. @code{@var{a}[@var{i}]} is defined as | |
7312 | @code{*(@var{a}+@var{i})}. Same precedence as @code{->}. | |
7313 | ||
7314 | @item () | |
7315 | Function parameter list. Same precedence as @code{->}. | |
7316 | ||
c906108c | 7317 | @item :: |
b37052ae | 7318 | C@t{++} scope resolution operator. Defined on @code{struct}, @code{union}, |
7a292a7a | 7319 | and @code{class} types. |
c906108c SS |
7320 | |
7321 | @item :: | |
7a292a7a SS |
7322 | Doubled colons also represent the @value{GDBN} scope operator |
7323 | (@pxref{Expressions, ,Expressions}). Same precedence as @code{::}, | |
7324 | above. | |
c906108c SS |
7325 | @end table |
7326 | ||
c906108c SS |
7327 | If an operator is redefined in the user code, @value{GDBN} usually |
7328 | attempts to invoke the redefined version instead of using the operator's | |
7329 | predefined meaning. | |
c906108c | 7330 | |
c906108c | 7331 | @menu |
5d161b24 | 7332 | * C Constants:: |
c906108c SS |
7333 | @end menu |
7334 | ||
6d2ebf8b | 7335 | @node C Constants |
b37052ae | 7336 | @subsubsection C and C@t{++} constants |
c906108c | 7337 | |
b37052ae | 7338 | @cindex C and C@t{++} constants |
c906108c | 7339 | |
b37052ae | 7340 | @value{GDBN} allows you to express the constants of C and C@t{++} in the |
c906108c | 7341 | following ways: |
c906108c SS |
7342 | |
7343 | @itemize @bullet | |
7344 | @item | |
7345 | Integer constants are a sequence of digits. Octal constants are | |
7346 | specified by a leading @samp{0} (i.e. zero), and hexadecimal constants by | |
7347 | a leading @samp{0x} or @samp{0X}. Constants may also end with a letter | |
7348 | @samp{l}, specifying that the constant should be treated as a | |
7349 | @code{long} value. | |
7350 | ||
7351 | @item | |
7352 | Floating point constants are a sequence of digits, followed by a decimal | |
7353 | point, followed by a sequence of digits, and optionally followed by an | |
7354 | exponent. An exponent is of the form: | |
7355 | @samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another | |
7356 | sequence of digits. The @samp{+} is optional for positive exponents. | |
d4f3574e SS |
7357 | A floating-point constant may also end with a letter @samp{f} or |
7358 | @samp{F}, specifying that the constant should be treated as being of | |
7359 | the @code{float} (as opposed to the default @code{double}) type; or with | |
7360 | a letter @samp{l} or @samp{L}, which specifies a @code{long double} | |
7361 | constant. | |
c906108c SS |
7362 | |
7363 | @item | |
7364 | Enumerated constants consist of enumerated identifiers, or their | |
7365 | integral equivalents. | |
7366 | ||
7367 | @item | |
7368 | Character constants are a single character surrounded by single quotes | |
7369 | (@code{'}), or a number---the ordinal value of the corresponding character | |
d4f3574e | 7370 | (usually its @sc{ascii} value). Within quotes, the single character may |
c906108c SS |
7371 | be represented by a letter or by @dfn{escape sequences}, which are of |
7372 | the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation | |
7373 | of the character's ordinal value; or of the form @samp{\@var{x}}, where | |
7374 | @samp{@var{x}} is a predefined special character---for example, | |
7375 | @samp{\n} for newline. | |
7376 | ||
7377 | @item | |
96a2c332 SS |
7378 | String constants are a sequence of character constants surrounded by |
7379 | double quotes (@code{"}). Any valid character constant (as described | |
7380 | above) may appear. Double quotes within the string must be preceded by | |
7381 | a backslash, so for instance @samp{"a\"b'c"} is a string of five | |
7382 | characters. | |
c906108c SS |
7383 | |
7384 | @item | |
7385 | Pointer constants are an integral value. You can also write pointers | |
7386 | to constants using the C operator @samp{&}. | |
7387 | ||
7388 | @item | |
7389 | Array constants are comma-separated lists surrounded by braces @samp{@{} | |
7390 | and @samp{@}}; for example, @samp{@{1,2,3@}} is a three-element array of | |
7391 | integers, @samp{@{@{1,2@}, @{3,4@}, @{5,6@}@}} is a three-by-two array, | |
7392 | and @samp{@{&"hi", &"there", &"fred"@}} is a three-element array of pointers. | |
7393 | @end itemize | |
7394 | ||
c906108c | 7395 | @menu |
5d161b24 DB |
7396 | * C plus plus expressions:: |
7397 | * C Defaults:: | |
7398 | * C Checks:: | |
c906108c | 7399 | |
5d161b24 | 7400 | * Debugging C:: |
c906108c SS |
7401 | @end menu |
7402 | ||
6d2ebf8b | 7403 | @node C plus plus expressions |
b37052ae EZ |
7404 | @subsubsection C@t{++} expressions |
7405 | ||
7406 | @cindex expressions in C@t{++} | |
7407 | @value{GDBN} expression handling can interpret most C@t{++} expressions. | |
7408 | ||
7409 | @cindex C@t{++} support, not in @sc{coff} | |
7410 | @cindex @sc{coff} versus C@t{++} | |
7411 | @cindex C@t{++} and object formats | |
7412 | @cindex object formats and C@t{++} | |
7413 | @cindex a.out and C@t{++} | |
7414 | @cindex @sc{ecoff} and C@t{++} | |
7415 | @cindex @sc{xcoff} and C@t{++} | |
7416 | @cindex @sc{elf}/stabs and C@t{++} | |
7417 | @cindex @sc{elf}/@sc{dwarf} and C@t{++} | |
c906108c SS |
7418 | @c FIXME!! GDB may eventually be able to debug C++ using DWARF; check |
7419 | @c periodically whether this has happened... | |
7420 | @quotation | |
b37052ae EZ |
7421 | @emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the |
7422 | proper compiler. Typically, C@t{++} debugging depends on the use of | |
c906108c SS |
7423 | additional debugging information in the symbol table, and thus requires |
7424 | special support. In particular, if your compiler generates a.out, MIPS | |
7425 | @sc{ecoff}, RS/6000 @sc{xcoff}, or @sc{elf} with stabs extensions to the | |
7426 | symbol table, these facilities are all available. (With @sc{gnu} CC, | |
7427 | you can use the @samp{-gstabs} option to request stabs debugging | |
7428 | extensions explicitly.) Where the object code format is standard | |
b37052ae | 7429 | @sc{coff} or @sc{dwarf} in @sc{elf}, on the other hand, most of the C@t{++} |
c906108c SS |
7430 | support in @value{GDBN} does @emph{not} work. |
7431 | @end quotation | |
c906108c SS |
7432 | |
7433 | @enumerate | |
7434 | ||
7435 | @cindex member functions | |
7436 | @item | |
7437 | Member function calls are allowed; you can use expressions like | |
7438 | ||
7439 | @example | |
7440 | count = aml->GetOriginal(x, y) | |
7441 | @end example | |
7442 | ||
41afff9a | 7443 | @vindex this@r{, inside C@t{++} member functions} |
b37052ae | 7444 | @cindex namespace in C@t{++} |
c906108c SS |
7445 | @item |
7446 | While a member function is active (in the selected stack frame), your | |
7447 | expressions have the same namespace available as the member function; | |
7448 | that is, @value{GDBN} allows implicit references to the class instance | |
b37052ae | 7449 | pointer @code{this} following the same rules as C@t{++}. |
c906108c | 7450 | |
c906108c | 7451 | @cindex call overloaded functions |
d4f3574e | 7452 | @cindex overloaded functions, calling |
b37052ae | 7453 | @cindex type conversions in C@t{++} |
c906108c SS |
7454 | @item |
7455 | You can call overloaded functions; @value{GDBN} resolves the function | |
d4f3574e | 7456 | call to the right definition, with some restrictions. @value{GDBN} does not |
c906108c SS |
7457 | perform overload resolution involving user-defined type conversions, |
7458 | calls to constructors, or instantiations of templates that do not exist | |
7459 | in the program. It also cannot handle ellipsis argument lists or | |
7460 | default arguments. | |
7461 | ||
7462 | It does perform integral conversions and promotions, floating-point | |
7463 | promotions, arithmetic conversions, pointer conversions, conversions of | |
7464 | class objects to base classes, and standard conversions such as those of | |
7465 | functions or arrays to pointers; it requires an exact match on the | |
7466 | number of function arguments. | |
7467 | ||
7468 | Overload resolution is always performed, unless you have specified | |
7469 | @code{set overload-resolution off}. @xref{Debugging C plus plus, | |
b37052ae | 7470 | ,@value{GDBN} features for C@t{++}}. |
c906108c | 7471 | |
d4f3574e | 7472 | You must specify @code{set overload-resolution off} in order to use an |
c906108c SS |
7473 | explicit function signature to call an overloaded function, as in |
7474 | @smallexample | |
7475 | p 'foo(char,int)'('x', 13) | |
7476 | @end smallexample | |
d4f3574e | 7477 | |
c906108c | 7478 | The @value{GDBN} command-completion facility can simplify this; |
d4f3574e | 7479 | see @ref{Completion, ,Command completion}. |
c906108c | 7480 | |
c906108c SS |
7481 | @cindex reference declarations |
7482 | @item | |
b37052ae EZ |
7483 | @value{GDBN} understands variables declared as C@t{++} references; you can use |
7484 | them in expressions just as you do in C@t{++} source---they are automatically | |
c906108c SS |
7485 | dereferenced. |
7486 | ||
7487 | In the parameter list shown when @value{GDBN} displays a frame, the values of | |
7488 | reference variables are not displayed (unlike other variables); this | |
7489 | avoids clutter, since references are often used for large structures. | |
7490 | The @emph{address} of a reference variable is always shown, unless | |
7491 | you have specified @samp{set print address off}. | |
7492 | ||
7493 | @item | |
b37052ae | 7494 | @value{GDBN} supports the C@t{++} name resolution operator @code{::}---your |
c906108c SS |
7495 | expressions can use it just as expressions in your program do. Since |
7496 | one scope may be defined in another, you can use @code{::} repeatedly if | |
7497 | necessary, for example in an expression like | |
7498 | @samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows | |
b37052ae | 7499 | resolving name scope by reference to source files, in both C and C@t{++} |
c906108c SS |
7500 | debugging (@pxref{Variables, ,Program variables}). |
7501 | @end enumerate | |
7502 | ||
b37052ae | 7503 | In addition, when used with HP's C@t{++} compiler, @value{GDBN} supports |
53a5351d JM |
7504 | calling virtual functions correctly, printing out virtual bases of |
7505 | objects, calling functions in a base subobject, casting objects, and | |
7506 | invoking user-defined operators. | |
c906108c | 7507 | |
6d2ebf8b | 7508 | @node C Defaults |
b37052ae | 7509 | @subsubsection C and C@t{++} defaults |
7a292a7a | 7510 | |
b37052ae | 7511 | @cindex C and C@t{++} defaults |
c906108c | 7512 | |
c906108c SS |
7513 | If you allow @value{GDBN} to set type and range checking automatically, they |
7514 | both default to @code{off} whenever the working language changes to | |
b37052ae | 7515 | C or C@t{++}. This happens regardless of whether you or @value{GDBN} |
c906108c | 7516 | selects the working language. |
c906108c SS |
7517 | |
7518 | If you allow @value{GDBN} to set the language automatically, it | |
7519 | recognizes source files whose names end with @file{.c}, @file{.C}, or | |
7520 | @file{.cc}, etc, and when @value{GDBN} enters code compiled from one of | |
b37052ae | 7521 | these files, it sets the working language to C or C@t{++}. |
c906108c SS |
7522 | @xref{Automatically, ,Having @value{GDBN} infer the source language}, |
7523 | for further details. | |
7524 | ||
c906108c SS |
7525 | @c Type checking is (a) primarily motivated by Modula-2, and (b) |
7526 | @c unimplemented. If (b) changes, it might make sense to let this node | |
7527 | @c appear even if Mod-2 does not, but meanwhile ignore it. roland 16jul93. | |
7a292a7a | 7528 | |
6d2ebf8b | 7529 | @node C Checks |
b37052ae | 7530 | @subsubsection C and C@t{++} type and range checks |
7a292a7a | 7531 | |
b37052ae | 7532 | @cindex C and C@t{++} checks |
c906108c | 7533 | |
b37052ae | 7534 | By default, when @value{GDBN} parses C or C@t{++} expressions, type checking |
c906108c SS |
7535 | is not used. However, if you turn type checking on, @value{GDBN} |
7536 | considers two variables type equivalent if: | |
7537 | ||
7538 | @itemize @bullet | |
7539 | @item | |
7540 | The two variables are structured and have the same structure, union, or | |
7541 | enumerated tag. | |
7542 | ||
7543 | @item | |
7544 | The two variables have the same type name, or types that have been | |
7545 | declared equivalent through @code{typedef}. | |
7546 | ||
7547 | @ignore | |
7548 | @c leaving this out because neither J Gilmore nor R Pesch understand it. | |
7549 | @c FIXME--beers? | |
7550 | @item | |
7551 | The two @code{struct}, @code{union}, or @code{enum} variables are | |
7552 | declared in the same declaration. (Note: this may not be true for all C | |
7553 | compilers.) | |
7554 | @end ignore | |
7555 | @end itemize | |
7556 | ||
7557 | Range checking, if turned on, is done on mathematical operations. Array | |
7558 | indices are not checked, since they are often used to index a pointer | |
7559 | that is not itself an array. | |
c906108c | 7560 | |
6d2ebf8b | 7561 | @node Debugging C |
c906108c | 7562 | @subsubsection @value{GDBN} and C |
c906108c SS |
7563 | |
7564 | The @code{set print union} and @code{show print union} commands apply to | |
7565 | the @code{union} type. When set to @samp{on}, any @code{union} that is | |
7a292a7a SS |
7566 | inside a @code{struct} or @code{class} is also printed. Otherwise, it |
7567 | appears as @samp{@{...@}}. | |
c906108c SS |
7568 | |
7569 | The @code{@@} operator aids in the debugging of dynamic arrays, formed | |
7570 | with pointers and a memory allocation function. @xref{Expressions, | |
7571 | ,Expressions}. | |
7572 | ||
c906108c | 7573 | @menu |
5d161b24 | 7574 | * Debugging C plus plus:: |
c906108c SS |
7575 | @end menu |
7576 | ||
6d2ebf8b | 7577 | @node Debugging C plus plus |
b37052ae | 7578 | @subsubsection @value{GDBN} features for C@t{++} |
c906108c | 7579 | |
b37052ae | 7580 | @cindex commands for C@t{++} |
7a292a7a | 7581 | |
b37052ae EZ |
7582 | Some @value{GDBN} commands are particularly useful with C@t{++}, and some are |
7583 | designed specifically for use with C@t{++}. Here is a summary: | |
c906108c SS |
7584 | |
7585 | @table @code | |
7586 | @cindex break in overloaded functions | |
7587 | @item @r{breakpoint menus} | |
7588 | When you want a breakpoint in a function whose name is overloaded, | |
7589 | @value{GDBN} breakpoint menus help you specify which function definition | |
7590 | you want. @xref{Breakpoint Menus,,Breakpoint menus}. | |
7591 | ||
b37052ae | 7592 | @cindex overloading in C@t{++} |
c906108c SS |
7593 | @item rbreak @var{regex} |
7594 | Setting breakpoints using regular expressions is helpful for setting | |
7595 | breakpoints on overloaded functions that are not members of any special | |
7596 | classes. | |
7597 | @xref{Set Breaks, ,Setting breakpoints}. | |
7598 | ||
b37052ae | 7599 | @cindex C@t{++} exception handling |
c906108c SS |
7600 | @item catch throw |
7601 | @itemx catch catch | |
b37052ae | 7602 | Debug C@t{++} exception handling using these commands. @xref{Set |
c906108c SS |
7603 | Catchpoints, , Setting catchpoints}. |
7604 | ||
7605 | @cindex inheritance | |
7606 | @item ptype @var{typename} | |
7607 | Print inheritance relationships as well as other information for type | |
7608 | @var{typename}. | |
7609 | @xref{Symbols, ,Examining the Symbol Table}. | |
7610 | ||
b37052ae | 7611 | @cindex C@t{++} symbol display |
c906108c SS |
7612 | @item set print demangle |
7613 | @itemx show print demangle | |
7614 | @itemx set print asm-demangle | |
7615 | @itemx show print asm-demangle | |
b37052ae EZ |
7616 | Control whether C@t{++} symbols display in their source form, both when |
7617 | displaying code as C@t{++} source and when displaying disassemblies. | |
c906108c SS |
7618 | @xref{Print Settings, ,Print settings}. |
7619 | ||
7620 | @item set print object | |
7621 | @itemx show print object | |
7622 | Choose whether to print derived (actual) or declared types of objects. | |
7623 | @xref{Print Settings, ,Print settings}. | |
7624 | ||
7625 | @item set print vtbl | |
7626 | @itemx show print vtbl | |
7627 | Control the format for printing virtual function tables. | |
7628 | @xref{Print Settings, ,Print settings}. | |
c906108c | 7629 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 7630 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
7631 | |
7632 | @kindex set overload-resolution | |
d4f3574e | 7633 | @cindex overloaded functions, overload resolution |
c906108c | 7634 | @item set overload-resolution on |
b37052ae | 7635 | Enable overload resolution for C@t{++} expression evaluation. The default |
c906108c SS |
7636 | is on. For overloaded functions, @value{GDBN} evaluates the arguments |
7637 | and searches for a function whose signature matches the argument types, | |
b37052ae | 7638 | using the standard C@t{++} conversion rules (see @ref{C plus plus expressions, ,C@t{++} |
d4f3574e | 7639 | expressions}, for details). If it cannot find a match, it emits a |
c906108c SS |
7640 | message. |
7641 | ||
7642 | @item set overload-resolution off | |
b37052ae | 7643 | Disable overload resolution for C@t{++} expression evaluation. For |
c906108c SS |
7644 | overloaded functions that are not class member functions, @value{GDBN} |
7645 | chooses the first function of the specified name that it finds in the | |
7646 | symbol table, whether or not its arguments are of the correct type. For | |
7647 | overloaded functions that are class member functions, @value{GDBN} | |
7648 | searches for a function whose signature @emph{exactly} matches the | |
7649 | argument types. | |
c906108c SS |
7650 | |
7651 | @item @r{Overloaded symbol names} | |
7652 | You can specify a particular definition of an overloaded symbol, using | |
b37052ae | 7653 | the same notation that is used to declare such symbols in C@t{++}: type |
c906108c SS |
7654 | @code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can |
7655 | also use the @value{GDBN} command-line word completion facilities to list the | |
7656 | available choices, or to finish the type list for you. | |
7657 | @xref{Completion,, Command completion}, for details on how to do this. | |
7658 | @end table | |
c906108c | 7659 | |
6d2ebf8b | 7660 | @node Modula-2 |
c906108c | 7661 | @subsection Modula-2 |
7a292a7a | 7662 | |
d4f3574e | 7663 | @cindex Modula-2, @value{GDBN} support |
c906108c SS |
7664 | |
7665 | The extensions made to @value{GDBN} to support Modula-2 only support | |
7666 | output from the @sc{gnu} Modula-2 compiler (which is currently being | |
7667 | developed). Other Modula-2 compilers are not currently supported, and | |
7668 | attempting to debug executables produced by them is most likely | |
7669 | to give an error as @value{GDBN} reads in the executable's symbol | |
7670 | table. | |
7671 | ||
7672 | @cindex expressions in Modula-2 | |
7673 | @menu | |
7674 | * M2 Operators:: Built-in operators | |
7675 | * Built-In Func/Proc:: Built-in functions and procedures | |
7676 | * M2 Constants:: Modula-2 constants | |
7677 | * M2 Defaults:: Default settings for Modula-2 | |
7678 | * Deviations:: Deviations from standard Modula-2 | |
7679 | * M2 Checks:: Modula-2 type and range checks | |
7680 | * M2 Scope:: The scope operators @code{::} and @code{.} | |
7681 | * GDB/M2:: @value{GDBN} and Modula-2 | |
7682 | @end menu | |
7683 | ||
6d2ebf8b | 7684 | @node M2 Operators |
c906108c SS |
7685 | @subsubsection Operators |
7686 | @cindex Modula-2 operators | |
7687 | ||
7688 | Operators must be defined on values of specific types. For instance, | |
7689 | @code{+} is defined on numbers, but not on structures. Operators are | |
7690 | often defined on groups of types. For the purposes of Modula-2, the | |
7691 | following definitions hold: | |
7692 | ||
7693 | @itemize @bullet | |
7694 | ||
7695 | @item | |
7696 | @emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and | |
7697 | their subranges. | |
7698 | ||
7699 | @item | |
7700 | @emph{Character types} consist of @code{CHAR} and its subranges. | |
7701 | ||
7702 | @item | |
7703 | @emph{Floating-point types} consist of @code{REAL}. | |
7704 | ||
7705 | @item | |
7706 | @emph{Pointer types} consist of anything declared as @code{POINTER TO | |
7707 | @var{type}}. | |
7708 | ||
7709 | @item | |
7710 | @emph{Scalar types} consist of all of the above. | |
7711 | ||
7712 | @item | |
7713 | @emph{Set types} consist of @code{SET} and @code{BITSET} types. | |
7714 | ||
7715 | @item | |
7716 | @emph{Boolean types} consist of @code{BOOLEAN}. | |
7717 | @end itemize | |
7718 | ||
7719 | @noindent | |
7720 | The following operators are supported, and appear in order of | |
7721 | increasing precedence: | |
7722 | ||
7723 | @table @code | |
7724 | @item , | |
7725 | Function argument or array index separator. | |
7726 | ||
7727 | @item := | |
7728 | Assignment. The value of @var{var} @code{:=} @var{value} is | |
7729 | @var{value}. | |
7730 | ||
7731 | @item <@r{, }> | |
7732 | Less than, greater than on integral, floating-point, or enumerated | |
7733 | types. | |
7734 | ||
7735 | @item <=@r{, }>= | |
96a2c332 | 7736 | Less than or equal to, greater than or equal to |
c906108c SS |
7737 | on integral, floating-point and enumerated types, or set inclusion on |
7738 | set types. Same precedence as @code{<}. | |
7739 | ||
7740 | @item =@r{, }<>@r{, }# | |
7741 | Equality and two ways of expressing inequality, valid on scalar types. | |
7742 | Same precedence as @code{<}. In @value{GDBN} scripts, only @code{<>} is | |
7743 | available for inequality, since @code{#} conflicts with the script | |
7744 | comment character. | |
7745 | ||
7746 | @item IN | |
7747 | Set membership. Defined on set types and the types of their members. | |
7748 | Same precedence as @code{<}. | |
7749 | ||
7750 | @item OR | |
7751 | Boolean disjunction. Defined on boolean types. | |
7752 | ||
7753 | @item AND@r{, }& | |
d4f3574e | 7754 | Boolean conjunction. Defined on boolean types. |
c906108c SS |
7755 | |
7756 | @item @@ | |
7757 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
7758 | ||
7759 | @item +@r{, }- | |
7760 | Addition and subtraction on integral and floating-point types, or union | |
7761 | and difference on set types. | |
7762 | ||
7763 | @item * | |
7764 | Multiplication on integral and floating-point types, or set intersection | |
7765 | on set types. | |
7766 | ||
7767 | @item / | |
7768 | Division on floating-point types, or symmetric set difference on set | |
7769 | types. Same precedence as @code{*}. | |
7770 | ||
7771 | @item DIV@r{, }MOD | |
7772 | Integer division and remainder. Defined on integral types. Same | |
7773 | precedence as @code{*}. | |
7774 | ||
7775 | @item - | |
7776 | Negative. Defined on @code{INTEGER} and @code{REAL} data. | |
7777 | ||
7778 | @item ^ | |
7779 | Pointer dereferencing. Defined on pointer types. | |
7780 | ||
7781 | @item NOT | |
7782 | Boolean negation. Defined on boolean types. Same precedence as | |
7783 | @code{^}. | |
7784 | ||
7785 | @item . | |
7786 | @code{RECORD} field selector. Defined on @code{RECORD} data. Same | |
7787 | precedence as @code{^}. | |
7788 | ||
7789 | @item [] | |
7790 | Array indexing. Defined on @code{ARRAY} data. Same precedence as @code{^}. | |
7791 | ||
7792 | @item () | |
7793 | Procedure argument list. Defined on @code{PROCEDURE} objects. Same precedence | |
7794 | as @code{^}. | |
7795 | ||
7796 | @item ::@r{, }. | |
7797 | @value{GDBN} and Modula-2 scope operators. | |
7798 | @end table | |
7799 | ||
7800 | @quotation | |
7801 | @emph{Warning:} Sets and their operations are not yet supported, so @value{GDBN} | |
7802 | treats the use of the operator @code{IN}, or the use of operators | |
7803 | @code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#}, | |
7804 | @code{<=}, and @code{>=} on sets as an error. | |
7805 | @end quotation | |
7806 | ||
cb51c4e0 | 7807 | |
6d2ebf8b | 7808 | @node Built-In Func/Proc |
c906108c | 7809 | @subsubsection Built-in functions and procedures |
cb51c4e0 | 7810 | @cindex Modula-2 built-ins |
c906108c SS |
7811 | |
7812 | Modula-2 also makes available several built-in procedures and functions. | |
7813 | In describing these, the following metavariables are used: | |
7814 | ||
7815 | @table @var | |
7816 | ||
7817 | @item a | |
7818 | represents an @code{ARRAY} variable. | |
7819 | ||
7820 | @item c | |
7821 | represents a @code{CHAR} constant or variable. | |
7822 | ||
7823 | @item i | |
7824 | represents a variable or constant of integral type. | |
7825 | ||
7826 | @item m | |
7827 | represents an identifier that belongs to a set. Generally used in the | |
7828 | same function with the metavariable @var{s}. The type of @var{s} should | |
7829 | be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}). | |
7830 | ||
7831 | @item n | |
7832 | represents a variable or constant of integral or floating-point type. | |
7833 | ||
7834 | @item r | |
7835 | represents a variable or constant of floating-point type. | |
7836 | ||
7837 | @item t | |
7838 | represents a type. | |
7839 | ||
7840 | @item v | |
7841 | represents a variable. | |
7842 | ||
7843 | @item x | |
7844 | represents a variable or constant of one of many types. See the | |
7845 | explanation of the function for details. | |
7846 | @end table | |
7847 | ||
7848 | All Modula-2 built-in procedures also return a result, described below. | |
7849 | ||
7850 | @table @code | |
7851 | @item ABS(@var{n}) | |
7852 | Returns the absolute value of @var{n}. | |
7853 | ||
7854 | @item CAP(@var{c}) | |
7855 | If @var{c} is a lower case letter, it returns its upper case | |
c3f6f71d | 7856 | equivalent, otherwise it returns its argument. |
c906108c SS |
7857 | |
7858 | @item CHR(@var{i}) | |
7859 | Returns the character whose ordinal value is @var{i}. | |
7860 | ||
7861 | @item DEC(@var{v}) | |
c3f6f71d | 7862 | Decrements the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
7863 | |
7864 | @item DEC(@var{v},@var{i}) | |
7865 | Decrements the value in the variable @var{v} by @var{i}. Returns the | |
7866 | new value. | |
7867 | ||
7868 | @item EXCL(@var{m},@var{s}) | |
7869 | Removes the element @var{m} from the set @var{s}. Returns the new | |
7870 | set. | |
7871 | ||
7872 | @item FLOAT(@var{i}) | |
7873 | Returns the floating point equivalent of the integer @var{i}. | |
7874 | ||
7875 | @item HIGH(@var{a}) | |
7876 | Returns the index of the last member of @var{a}. | |
7877 | ||
7878 | @item INC(@var{v}) | |
c3f6f71d | 7879 | Increments the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
7880 | |
7881 | @item INC(@var{v},@var{i}) | |
7882 | Increments the value in the variable @var{v} by @var{i}. Returns the | |
7883 | new value. | |
7884 | ||
7885 | @item INCL(@var{m},@var{s}) | |
7886 | Adds the element @var{m} to the set @var{s} if it is not already | |
7887 | there. Returns the new set. | |
7888 | ||
7889 | @item MAX(@var{t}) | |
7890 | Returns the maximum value of the type @var{t}. | |
7891 | ||
7892 | @item MIN(@var{t}) | |
7893 | Returns the minimum value of the type @var{t}. | |
7894 | ||
7895 | @item ODD(@var{i}) | |
7896 | Returns boolean TRUE if @var{i} is an odd number. | |
7897 | ||
7898 | @item ORD(@var{x}) | |
7899 | Returns the ordinal value of its argument. For example, the ordinal | |
c3f6f71d JM |
7900 | value of a character is its @sc{ascii} value (on machines supporting the |
7901 | @sc{ascii} character set). @var{x} must be of an ordered type, which include | |
c906108c SS |
7902 | integral, character and enumerated types. |
7903 | ||
7904 | @item SIZE(@var{x}) | |
7905 | Returns the size of its argument. @var{x} can be a variable or a type. | |
7906 | ||
7907 | @item TRUNC(@var{r}) | |
7908 | Returns the integral part of @var{r}. | |
7909 | ||
7910 | @item VAL(@var{t},@var{i}) | |
7911 | Returns the member of the type @var{t} whose ordinal value is @var{i}. | |
7912 | @end table | |
7913 | ||
7914 | @quotation | |
7915 | @emph{Warning:} Sets and their operations are not yet supported, so | |
7916 | @value{GDBN} treats the use of procedures @code{INCL} and @code{EXCL} as | |
7917 | an error. | |
7918 | @end quotation | |
7919 | ||
7920 | @cindex Modula-2 constants | |
6d2ebf8b | 7921 | @node M2 Constants |
c906108c SS |
7922 | @subsubsection Constants |
7923 | ||
7924 | @value{GDBN} allows you to express the constants of Modula-2 in the following | |
7925 | ways: | |
7926 | ||
7927 | @itemize @bullet | |
7928 | ||
7929 | @item | |
7930 | Integer constants are simply a sequence of digits. When used in an | |
7931 | expression, a constant is interpreted to be type-compatible with the | |
7932 | rest of the expression. Hexadecimal integers are specified by a | |
7933 | trailing @samp{H}, and octal integers by a trailing @samp{B}. | |
7934 | ||
7935 | @item | |
7936 | Floating point constants appear as a sequence of digits, followed by a | |
7937 | decimal point and another sequence of digits. An optional exponent can | |
7938 | then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where | |
7939 | @samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the | |
7940 | digits of the floating point constant must be valid decimal (base 10) | |
7941 | digits. | |
7942 | ||
7943 | @item | |
7944 | Character constants consist of a single character enclosed by a pair of | |
7945 | like quotes, either single (@code{'}) or double (@code{"}). They may | |
c3f6f71d | 7946 | also be expressed by their ordinal value (their @sc{ascii} value, usually) |
c906108c SS |
7947 | followed by a @samp{C}. |
7948 | ||
7949 | @item | |
7950 | String constants consist of a sequence of characters enclosed by a | |
7951 | pair of like quotes, either single (@code{'}) or double (@code{"}). | |
7952 | Escape sequences in the style of C are also allowed. @xref{C | |
b37052ae | 7953 | Constants, ,C and C@t{++} constants}, for a brief explanation of escape |
c906108c SS |
7954 | sequences. |
7955 | ||
7956 | @item | |
7957 | Enumerated constants consist of an enumerated identifier. | |
7958 | ||
7959 | @item | |
7960 | Boolean constants consist of the identifiers @code{TRUE} and | |
7961 | @code{FALSE}. | |
7962 | ||
7963 | @item | |
7964 | Pointer constants consist of integral values only. | |
7965 | ||
7966 | @item | |
7967 | Set constants are not yet supported. | |
7968 | @end itemize | |
7969 | ||
6d2ebf8b | 7970 | @node M2 Defaults |
c906108c SS |
7971 | @subsubsection Modula-2 defaults |
7972 | @cindex Modula-2 defaults | |
7973 | ||
7974 | If type and range checking are set automatically by @value{GDBN}, they | |
7975 | both default to @code{on} whenever the working language changes to | |
d4f3574e | 7976 | Modula-2. This happens regardless of whether you or @value{GDBN} |
c906108c SS |
7977 | selected the working language. |
7978 | ||
7979 | If you allow @value{GDBN} to set the language automatically, then entering | |
7980 | code compiled from a file whose name ends with @file{.mod} sets the | |
d4f3574e | 7981 | working language to Modula-2. @xref{Automatically, ,Having @value{GDBN} set |
c906108c SS |
7982 | the language automatically}, for further details. |
7983 | ||
6d2ebf8b | 7984 | @node Deviations |
c906108c SS |
7985 | @subsubsection Deviations from standard Modula-2 |
7986 | @cindex Modula-2, deviations from | |
7987 | ||
7988 | A few changes have been made to make Modula-2 programs easier to debug. | |
7989 | This is done primarily via loosening its type strictness: | |
7990 | ||
7991 | @itemize @bullet | |
7992 | @item | |
7993 | Unlike in standard Modula-2, pointer constants can be formed by | |
7994 | integers. This allows you to modify pointer variables during | |
7995 | debugging. (In standard Modula-2, the actual address contained in a | |
7996 | pointer variable is hidden from you; it can only be modified | |
7997 | through direct assignment to another pointer variable or expression that | |
7998 | returned a pointer.) | |
7999 | ||
8000 | @item | |
8001 | C escape sequences can be used in strings and characters to represent | |
8002 | non-printable characters. @value{GDBN} prints out strings with these | |
8003 | escape sequences embedded. Single non-printable characters are | |
8004 | printed using the @samp{CHR(@var{nnn})} format. | |
8005 | ||
8006 | @item | |
8007 | The assignment operator (@code{:=}) returns the value of its right-hand | |
8008 | argument. | |
8009 | ||
8010 | @item | |
8011 | All built-in procedures both modify @emph{and} return their argument. | |
8012 | @end itemize | |
8013 | ||
6d2ebf8b | 8014 | @node M2 Checks |
c906108c SS |
8015 | @subsubsection Modula-2 type and range checks |
8016 | @cindex Modula-2 checks | |
8017 | ||
8018 | @quotation | |
8019 | @emph{Warning:} in this release, @value{GDBN} does not yet perform type or | |
8020 | range checking. | |
8021 | @end quotation | |
8022 | @c FIXME remove warning when type/range checks added | |
8023 | ||
8024 | @value{GDBN} considers two Modula-2 variables type equivalent if: | |
8025 | ||
8026 | @itemize @bullet | |
8027 | @item | |
8028 | They are of types that have been declared equivalent via a @code{TYPE | |
8029 | @var{t1} = @var{t2}} statement | |
8030 | ||
8031 | @item | |
8032 | They have been declared on the same line. (Note: This is true of the | |
8033 | @sc{gnu} Modula-2 compiler, but it may not be true of other compilers.) | |
8034 | @end itemize | |
8035 | ||
8036 | As long as type checking is enabled, any attempt to combine variables | |
8037 | whose types are not equivalent is an error. | |
8038 | ||
8039 | Range checking is done on all mathematical operations, assignment, array | |
8040 | index bounds, and all built-in functions and procedures. | |
8041 | ||
6d2ebf8b | 8042 | @node M2 Scope |
c906108c SS |
8043 | @subsubsection The scope operators @code{::} and @code{.} |
8044 | @cindex scope | |
41afff9a | 8045 | @cindex @code{.}, Modula-2 scope operator |
c906108c SS |
8046 | @cindex colon, doubled as scope operator |
8047 | @ifinfo | |
41afff9a | 8048 | @vindex colon-colon@r{, in Modula-2} |
c906108c SS |
8049 | @c Info cannot handle :: but TeX can. |
8050 | @end ifinfo | |
8051 | @iftex | |
41afff9a | 8052 | @vindex ::@r{, in Modula-2} |
c906108c SS |
8053 | @end iftex |
8054 | ||
8055 | There are a few subtle differences between the Modula-2 scope operator | |
8056 | (@code{.}) and the @value{GDBN} scope operator (@code{::}). The two have | |
8057 | similar syntax: | |
8058 | ||
8059 | @example | |
8060 | ||
8061 | @var{module} . @var{id} | |
8062 | @var{scope} :: @var{id} | |
8063 | @end example | |
8064 | ||
8065 | @noindent | |
8066 | where @var{scope} is the name of a module or a procedure, | |
8067 | @var{module} the name of a module, and @var{id} is any declared | |
8068 | identifier within your program, except another module. | |
8069 | ||
8070 | Using the @code{::} operator makes @value{GDBN} search the scope | |
8071 | specified by @var{scope} for the identifier @var{id}. If it is not | |
8072 | found in the specified scope, then @value{GDBN} searches all scopes | |
8073 | enclosing the one specified by @var{scope}. | |
8074 | ||
8075 | Using the @code{.} operator makes @value{GDBN} search the current scope for | |
8076 | the identifier specified by @var{id} that was imported from the | |
8077 | definition module specified by @var{module}. With this operator, it is | |
8078 | an error if the identifier @var{id} was not imported from definition | |
8079 | module @var{module}, or if @var{id} is not an identifier in | |
8080 | @var{module}. | |
8081 | ||
6d2ebf8b | 8082 | @node GDB/M2 |
c906108c SS |
8083 | @subsubsection @value{GDBN} and Modula-2 |
8084 | ||
8085 | Some @value{GDBN} commands have little use when debugging Modula-2 programs. | |
8086 | Five subcommands of @code{set print} and @code{show print} apply | |
b37052ae | 8087 | specifically to C and C@t{++}: @samp{vtbl}, @samp{demangle}, |
c906108c | 8088 | @samp{asm-demangle}, @samp{object}, and @samp{union}. The first four |
b37052ae | 8089 | apply to C@t{++}, and the last to the C @code{union} type, which has no direct |
c906108c SS |
8090 | analogue in Modula-2. |
8091 | ||
8092 | The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available | |
d4f3574e | 8093 | with any language, is not useful with Modula-2. Its |
c906108c | 8094 | intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be |
b37052ae | 8095 | created in Modula-2 as they can in C or C@t{++}. However, because an |
c906108c | 8096 | address can be specified by an integral constant, the construct |
d4f3574e | 8097 | @samp{@{@var{type}@}@var{adrexp}} is still useful. |
c906108c SS |
8098 | |
8099 | @cindex @code{#} in Modula-2 | |
8100 | In @value{GDBN} scripts, the Modula-2 inequality operator @code{#} is | |
8101 | interpreted as the beginning of a comment. Use @code{<>} instead. | |
c906108c | 8102 | |
6d2ebf8b | 8103 | @node Chill |
cce74817 JM |
8104 | @subsection Chill |
8105 | ||
8106 | The extensions made to @value{GDBN} to support Chill only support output | |
d4f3574e | 8107 | from the @sc{gnu} Chill compiler. Other Chill compilers are not currently |
cce74817 JM |
8108 | supported, and attempting to debug executables produced by them is most |
8109 | likely to give an error as @value{GDBN} reads in the executable's symbol | |
8110 | table. | |
8111 | ||
d4f3574e SS |
8112 | @c This used to say "... following Chill related topics ...", but since |
8113 | @c menus are not shown in the printed manual, it would look awkward. | |
8114 | This section covers the Chill related topics and the features | |
cce74817 JM |
8115 | of @value{GDBN} which support these topics. |
8116 | ||
8117 | @menu | |
104c1213 JM |
8118 | * How modes are displayed:: How modes are displayed |
8119 | * Locations:: Locations and their accesses | |
cce74817 | 8120 | * Values and their Operations:: Values and their Operations |
5d161b24 | 8121 | * Chill type and range checks:: |
53a5351d | 8122 | * Chill defaults:: |
cce74817 JM |
8123 | @end menu |
8124 | ||
6d2ebf8b | 8125 | @node How modes are displayed |
cce74817 JM |
8126 | @subsubsection How modes are displayed |
8127 | ||
8128 | The Chill Datatype- (Mode) support of @value{GDBN} is directly related | |
d4f3574e | 8129 | with the functionality of the @sc{gnu} Chill compiler, and therefore deviates |
cce74817 JM |
8130 | slightly from the standard specification of the Chill language. The |
8131 | provided modes are: | |
d4f3574e SS |
8132 | |
8133 | @c FIXME: this @table's contents effectively disable @code by using @r | |
8134 | @c on every @item. So why does it need @code? | |
cce74817 JM |
8135 | @table @code |
8136 | @item @r{@emph{Discrete modes:}} | |
8137 | @itemize @bullet | |
8138 | @item | |
8139 | @emph{Integer Modes} which are predefined by @code{BYTE, UBYTE, INT, | |
8140 | UINT, LONG, ULONG}, | |
8141 | @item | |
5d161b24 | 8142 | @emph{Boolean Mode} which is predefined by @code{BOOL}, |
cce74817 | 8143 | @item |
5d161b24 | 8144 | @emph{Character Mode} which is predefined by @code{CHAR}, |
cce74817 JM |
8145 | @item |
8146 | @emph{Set Mode} which is displayed by the keyword @code{SET}. | |
8147 | @smallexample | |
8148 | (@value{GDBP}) ptype x | |
8149 | type = SET (karli = 10, susi = 20, fritzi = 100) | |
8150 | @end smallexample | |
8151 | If the type is an unnumbered set the set element values are omitted. | |
8152 | @item | |
6d2ebf8b SS |
8153 | @emph{Range Mode} which is displayed by |
8154 | @smallexample | |
8155 | @code{type = <basemode>(<lower bound> : <upper bound>)} | |
8156 | @end smallexample | |
8157 | where @code{<lower bound>, <upper bound>} can be of any discrete literal | |
8158 | expression (e.g. set element names). | |
cce74817 JM |
8159 | @end itemize |
8160 | ||
8161 | @item @r{@emph{Powerset Mode:}} | |
8162 | A Powerset Mode is displayed by the keyword @code{POWERSET} followed by | |
d4f3574e | 8163 | the member mode of the powerset. The member mode can be any discrete mode. |
cce74817 JM |
8164 | @smallexample |
8165 | (@value{GDBP}) ptype x | |
8166 | type = POWERSET SET (egon, hugo, otto) | |
8167 | @end smallexample | |
8168 | ||
8169 | @item @r{@emph{Reference Modes:}} | |
8170 | @itemize @bullet | |
8171 | @item | |
d4f3574e | 8172 | @emph{Bound Reference Mode} which is displayed by the keyword @code{REF} |
cce74817 JM |
8173 | followed by the mode name to which the reference is bound. |
8174 | @item | |
8175 | @emph{Free Reference Mode} which is displayed by the keyword @code{PTR}. | |
8176 | @end itemize | |
8177 | ||
8178 | @item @r{@emph{Procedure mode}} | |
8179 | The procedure mode is displayed by @code{type = PROC(<parameter list>) | |
8180 | <return mode> EXCEPTIONS (<exception list>)}. The @code{<parameter | |
d4f3574e SS |
8181 | list>} is a list of the parameter modes. @code{<return mode>} indicates |
8182 | the mode of the result of the procedure if any. The exceptionlist lists | |
cce74817 JM |
8183 | all possible exceptions which can be raised by the procedure. |
8184 | ||
8185 | @ignore | |
8186 | @item @r{@emph{Instance mode}} | |
8187 | The instance mode is represented by a structure, which has a static | |
5d161b24 | 8188 | type, and is therefore not really of interest. |
cce74817 JM |
8189 | @end ignore |
8190 | ||
5d161b24 | 8191 | @item @r{@emph{Synchronization Modes:}} |
cce74817 JM |
8192 | @itemize @bullet |
8193 | @item | |
6d2ebf8b SS |
8194 | @emph{Event Mode} which is displayed by |
8195 | @smallexample | |
8196 | @code{EVENT (<event length>)} | |
8197 | @end smallexample | |
cce74817 JM |
8198 | where @code{(<event length>)} is optional. |
8199 | @item | |
6d2ebf8b SS |
8200 | @emph{Buffer Mode} which is displayed by |
8201 | @smallexample | |
8202 | @code{BUFFER (<buffer length>)<buffer element mode>} | |
8203 | @end smallexample | |
8204 | where @code{(<buffer length>)} is optional. | |
cce74817 JM |
8205 | @end itemize |
8206 | ||
5d161b24 | 8207 | @item @r{@emph{Timing Modes:}} |
cce74817 JM |
8208 | @itemize @bullet |
8209 | @item | |
8210 | @emph{Duration Mode} which is predefined by @code{DURATION} | |
8211 | @item | |
8212 | @emph{Absolute Time Mode} which is predefined by @code{TIME} | |
8213 | @end itemize | |
8214 | ||
8215 | @item @r{@emph{Real Modes:}} | |
8216 | Real Modes are predefined with @code{REAL} and @code{LONG_REAL}. | |
8217 | ||
8218 | @item @r{@emph{String Modes:}} | |
8219 | @itemize @bullet | |
8220 | @item | |
6d2ebf8b SS |
8221 | @emph{Character String Mode} which is displayed by |
8222 | @smallexample | |
8223 | @code{CHARS(<string length>)} | |
8224 | @end smallexample | |
8225 | followed by the keyword @code{VARYING} if the String Mode is a varying | |
8226 | mode | |
cce74817 | 8227 | @item |
6d2ebf8b SS |
8228 | @emph{Bit String Mode} which is displayed by |
8229 | @smallexample | |
8230 | @code{BOOLS(<string | |
8231 | length>)} | |
8232 | @end smallexample | |
cce74817 JM |
8233 | @end itemize |
8234 | ||
8235 | @item @r{@emph{Array Mode:}} | |
8236 | The Array Mode is displayed by the keyword @code{ARRAY(<range>)} | |
8237 | followed by the element mode (which may in turn be an array mode). | |
8238 | @smallexample | |
8239 | (@value{GDBP}) ptype x | |
5d161b24 DB |
8240 | type = ARRAY (1:42) |
8241 | ARRAY (1:20) | |
cce74817 JM |
8242 | SET (karli = 10, susi = 20, fritzi = 100) |
8243 | @end smallexample | |
8244 | ||
5d161b24 | 8245 | @item @r{@emph{Structure Mode}} |
cce74817 | 8246 | The Structure mode is displayed by the keyword @code{STRUCT(<field |
d4f3574e SS |
8247 | list>)}. The @code{<field list>} consists of names and modes of fields |
8248 | of the structure. Variant structures have the keyword @code{CASE <field> | |
8249 | OF <variant fields> ESAC} in their field list. Since the current version | |
cce74817 JM |
8250 | of the GNU Chill compiler doesn't implement tag processing (no runtime |
8251 | checks of variant fields, and therefore no debugging info), the output | |
8252 | always displays all variant fields. | |
8253 | @smallexample | |
8254 | (@value{GDBP}) ptype str | |
8255 | type = STRUCT ( | |
8256 | as x, | |
8257 | bs x, | |
8258 | CASE bs OF | |
8259 | (karli): | |
8260 | cs a | |
8261 | (ott): | |
8262 | ds x | |
8263 | ESAC | |
8264 | ) | |
8265 | @end smallexample | |
8266 | @end table | |
8267 | ||
6d2ebf8b | 8268 | @node Locations |
cce74817 JM |
8269 | @subsubsection Locations and their accesses |
8270 | ||
8271 | A location in Chill is an object which can contain values. | |
8272 | ||
8273 | A value of a location is generally accessed by the (declared) name of | |
d4f3574e SS |
8274 | the location. The output conforms to the specification of values in |
8275 | Chill programs. How values are specified | |
8276 | is the topic of the next section, @ref{Values and their Operations}. | |
cce74817 JM |
8277 | |
8278 | The pseudo-location @code{RESULT} (or @code{result}) can be used to | |
8279 | display or change the result of a currently-active procedure: | |
d4f3574e | 8280 | |
cce74817 JM |
8281 | @smallexample |
8282 | set result := EXPR | |
8283 | @end smallexample | |
d4f3574e SS |
8284 | |
8285 | @noindent | |
8286 | This does the same as the Chill action @code{RESULT EXPR} (which | |
c3f6f71d | 8287 | is not available in @value{GDBN}). |
cce74817 JM |
8288 | |
8289 | Values of reference mode locations are printed by @code{PTR(<hex | |
8290 | value>)} in case of a free reference mode, and by @code{(REF <reference | |
d4f3574e | 8291 | mode>) (<hex-value>)} in case of a bound reference. @code{<hex value>} |
cce74817 JM |
8292 | represents the address where the reference points to. To access the |
8293 | value of the location referenced by the pointer, use the dereference | |
d4f3574e | 8294 | operator @samp{->}. |
cce74817 | 8295 | |
6d2ebf8b SS |
8296 | Values of procedure mode locations are displayed by |
8297 | @smallexample | |
8298 | @code{@{ PROC | |
cce74817 | 8299 | (<argument modes> ) <return mode> @} <address> <name of procedure |
6d2ebf8b SS |
8300 | location>} |
8301 | @end smallexample | |
8302 | @code{<argument modes>} is a list of modes according to the parameter | |
8303 | specification of the procedure and @code{<address>} shows the address of | |
8304 | the entry point. | |
cce74817 JM |
8305 | |
8306 | @ignore | |
8307 | Locations of instance modes are displayed just like a structure with two | |
8308 | fields specifying the @emph{process type} and the @emph{copy number} of | |
8309 | the investigated instance location@footnote{This comes from the current | |
d4f3574e SS |
8310 | implementation of instances. They are implemented as a structure (no |
8311 | na). The output should be something like @code{[<name of the process>; | |
8312 | <instance number>]}.}. The field names are @code{__proc_type} and | |
cce74817 JM |
8313 | @code{__proc_copy}. |
8314 | ||
8315 | Locations of synchronization modes are displayed like a structure with | |
8316 | the field name @code{__event_data} in case of a event mode location, and | |
8317 | like a structure with the field @code{__buffer_data} in case of a buffer | |
8318 | mode location (refer to previous paragraph). | |
8319 | ||
8320 | Structure Mode locations are printed by @code{[.<field name>: <value>, | |
d4f3574e | 8321 | ...]}. The @code{<field name>} corresponds to the structure mode |
cce74817 | 8322 | definition and the layout of @code{<value>} varies depending of the mode |
d4f3574e SS |
8323 | of the field. If the investigated structure mode location is of variant |
8324 | structure mode, the variant parts of the structure are enclosed in curled | |
8325 | braces (@samp{@{@}}). Fields enclosed by @samp{@{,@}} are residing | |
cce74817 | 8326 | on the same memory location and represent the current values of the |
d4f3574e | 8327 | memory location in their specific modes. Since no tag processing is done |
cce74817 | 8328 | all variants are displayed. A variant field is printed by |
d4f3574e | 8329 | @code{(<variant name>) = .<field name>: <value>}. (who implements the |
cce74817 JM |
8330 | stuff ???) |
8331 | @smallexample | |
8332 | (@value{GDBP}) print str1 $4 = [.as: 0, .bs: karli, .<TAG>: { (karli) = | |
8333 | [.cs: []], (susi) = [.ds: susi]}] | |
8334 | @end smallexample | |
8335 | @end ignore | |
8336 | ||
8337 | Substructures of string mode-, array mode- or structure mode-values | |
8338 | (e.g. array slices, fields of structure locations) are accessed using | |
d4f3574e SS |
8339 | certain operations which are described in the next section, @ref{Values |
8340 | and their Operations}. | |
cce74817 JM |
8341 | |
8342 | A location value may be interpreted as having a different mode using the | |
d4f3574e SS |
8343 | location conversion. This mode conversion is written as @code{<mode |
8344 | name>(<location>)}. The user has to consider that the sizes of the modes | |
8345 | have to be equal otherwise an error occurs. Furthermore, no range | |
8346 | checking of the location against the destination mode is performed, and | |
cce74817 | 8347 | therefore the result can be quite confusing. |
d4f3574e | 8348 | |
cce74817 JM |
8349 | @smallexample |
8350 | (@value{GDBP}) print int (s(3 up 4)) XXX TO be filled in !! XXX | |
8351 | @end smallexample | |
8352 | ||
6d2ebf8b | 8353 | @node Values and their Operations |
cce74817 JM |
8354 | @subsubsection Values and their Operations |
8355 | ||
8356 | Values are used to alter locations, to investigate complex structures in | |
8357 | more detail or to filter relevant information out of a large amount of | |
d4f3574e SS |
8358 | data. There are several (mode dependent) operations defined which enable |
8359 | such investigations. These operations are not only applicable to | |
cce74817 | 8360 | constant values but also to locations, which can become quite useful |
d4f3574e | 8361 | when debugging complex structures. During parsing the command line |
cce74817 JM |
8362 | (e.g. evaluating an expression) @value{GDBN} treats location names as |
8363 | the values behind these locations. | |
8364 | ||
d4f3574e | 8365 | This section describes how values have to be specified and which |
cce74817 JM |
8366 | operations are legal to be used with such values. |
8367 | ||
8368 | @table @code | |
8369 | @item Literal Values | |
d4f3574e SS |
8370 | Literal values are specified in the same manner as in @sc{gnu} Chill programs. |
8371 | For detailed specification refer to the @sc{gnu} Chill implementation Manual | |
cce74817 | 8372 | chapter 1.5. |
d4f3574e SS |
8373 | @c FIXME: if the Chill Manual is a Texinfo documents, the above should |
8374 | @c be converted to a @ref. | |
cce74817 | 8375 | |
5d161b24 | 8376 | @ignore |
cce74817 JM |
8377 | @itemize @bullet |
8378 | @item | |
8379 | @emph{Integer Literals} are specified in the same manner as in Chill | |
d4f3574e | 8380 | programs (refer to the Chill Standard z200/88 chpt 5.2.4.2) |
cce74817 JM |
8381 | @item |
8382 | @emph{Boolean Literals} are defined by @code{TRUE} and @code{FALSE}. | |
8383 | @item | |
8384 | @emph{Character Literals} are defined by @code{'<character>'}. (e.g. | |
8385 | @code{'M'}) | |
8386 | @item | |
8387 | @emph{Set Literals} are defined by a name which was specified in a set | |
d4f3574e | 8388 | mode. The value delivered by a Set Literal is the set value. This is |
b37052ae | 8389 | comparable to an enumeration in C/C@t{++} language. |
cce74817 | 8390 | @item |
d4f3574e | 8391 | @emph{Emptiness Literal} is predefined by @code{NULL}. The value of the |
cce74817 | 8392 | emptiness literal delivers either the empty reference value, the empty |
5d161b24 | 8393 | procedure value or the empty instance value. |
cce74817 JM |
8394 | |
8395 | @item | |
8396 | @emph{Character String Literals} are defined by a sequence of characters | |
d4f3574e | 8397 | enclosed in single- or double quotes. If a single- or double quote has |
cce74817 JM |
8398 | to be part of the string literal it has to be stuffed (specified twice). |
8399 | @item | |
8400 | @emph{Bitstring Literals} are specified in the same manner as in Chill | |
8401 | programs (refer z200/88 chpt 5.2.4.8). | |
8402 | @item | |
8403 | @emph{Floating point literals} are specified in the same manner as in | |
d4f3574e | 8404 | (gnu-)Chill programs (refer @sc{gnu} Chill implementation Manual chapter 1.5). |
cce74817 JM |
8405 | @end itemize |
8406 | @end ignore | |
8407 | ||
8408 | @item Tuple Values | |
8409 | A tuple is specified by @code{<mode name>[<tuple>]}, where @code{<mode | |
d4f3574e | 8410 | name>} can be omitted if the mode of the tuple is unambiguous. This |
cce74817 JM |
8411 | unambiguity is derived from the context of a evaluated expression. |
8412 | @code{<tuple>} can be one of the following: | |
d4f3574e | 8413 | |
cce74817 JM |
8414 | @itemize @bullet |
8415 | @item @emph{Powerset Tuple} | |
8416 | @item @emph{Array Tuple} | |
8417 | @item @emph{Structure Tuple} | |
8418 | Powerset tuples, array tuples and structure tuples are specified in the | |
d4f3574e | 8419 | same manner as in Chill programs refer to z200/88 chpt 5.2.5. |
cce74817 JM |
8420 | @end itemize |
8421 | ||
8422 | @item String Element Value | |
6d2ebf8b SS |
8423 | A string element value is specified by |
8424 | @smallexample | |
8425 | @code{<string value>(<index>)} | |
8426 | @end smallexample | |
d4f3574e | 8427 | where @code{<index>} is a integer expression. It delivers a character |
cce74817 JM |
8428 | value which is equivalent to the character indexed by @code{<index>} in |
8429 | the string. | |
8430 | ||
8431 | @item String Slice Value | |
8432 | A string slice value is specified by @code{<string value>(<slice | |
8433 | spec>)}, where @code{<slice spec>} can be either a range of integer | |
8434 | expressions or specified by @code{<start expr> up <size>}. | |
8435 | @code{<size>} denotes the number of elements which the slice contains. | |
8436 | The delivered value is a string value, which is part of the specified | |
8437 | string. | |
8438 | ||
8439 | @item Array Element Values | |
8440 | An array element value is specified by @code{<array value>(<expr>)} and | |
8441 | delivers a array element value of the mode of the specified array. | |
8442 | ||
8443 | @item Array Slice Values | |
8444 | An array slice is specified by @code{<array value>(<slice spec>)}, where | |
8445 | @code{<slice spec>} can be either a range specified by expressions or by | |
d4f3574e SS |
8446 | @code{<start expr> up <size>}. @code{<size>} denotes the number of |
8447 | arrayelements the slice contains. The delivered value is an array value | |
cce74817 JM |
8448 | which is part of the specified array. |
8449 | ||
8450 | @item Structure Field Values | |
8451 | A structure field value is derived by @code{<structure value>.<field | |
d4f3574e SS |
8452 | name>}, where @code{<field name>} indicates the name of a field specified |
8453 | in the mode definition of the structure. The mode of the delivered value | |
cce74817 JM |
8454 | corresponds to this mode definition in the structure definition. |
8455 | ||
8456 | @item Procedure Call Value | |
8457 | The procedure call value is derived from the return value of the | |
8458 | procedure@footnote{If a procedure call is used for instance in an | |
8459 | expression, then this procedure is called with all its side | |
d4f3574e | 8460 | effects. This can lead to confusing results if used carelessly.}. |
cce74817 | 8461 | |
d4f3574e | 8462 | Values of duration mode locations are represented by @code{ULONG} literals. |
cce74817 | 8463 | |
6d2ebf8b SS |
8464 | Values of time mode locations appear as |
8465 | @smallexample | |
8466 | @code{TIME(<secs>:<nsecs>)} | |
8467 | @end smallexample | |
8468 | ||
cce74817 JM |
8469 | |
8470 | @ignore | |
8471 | This is not implemented yet: | |
8472 | @item Built-in Value | |
8473 | @noindent | |
8474 | The following built in functions are provided: | |
d4f3574e | 8475 | |
cce74817 JM |
8476 | @table @code |
8477 | @item @code{ADDR()} | |
8478 | @item @code{NUM()} | |
8479 | @item @code{PRED()} | |
8480 | @item @code{SUCC()} | |
8481 | @item @code{ABS()} | |
8482 | @item @code{CARD()} | |
8483 | @item @code{MAX()} | |
8484 | @item @code{MIN()} | |
8485 | @item @code{SIZE()} | |
8486 | @item @code{UPPER()} | |
8487 | @item @code{LOWER()} | |
8488 | @item @code{LENGTH()} | |
8489 | @item @code{SIN()} | |
8490 | @item @code{COS()} | |
8491 | @item @code{TAN()} | |
8492 | @item @code{ARCSIN()} | |
8493 | @item @code{ARCCOS()} | |
8494 | @item @code{ARCTAN()} | |
8495 | @item @code{EXP()} | |
8496 | @item @code{LN()} | |
8497 | @item @code{LOG()} | |
8498 | @item @code{SQRT()} | |
8499 | @end table | |
8500 | ||
8501 | For a detailed description refer to the GNU Chill implementation manual | |
8502 | chapter 1.6. | |
8503 | @end ignore | |
8504 | ||
8505 | @item Zero-adic Operator Value | |
8506 | The zero-adic operator value is derived from the instance value for the | |
8507 | current active process. | |
8508 | ||
8509 | @item Expression Values | |
8510 | The value delivered by an expression is the result of the evaluation of | |
d4f3574e | 8511 | the specified expression. If there are error conditions (mode |
cce74817 | 8512 | incompatibility, etc.) the evaluation of expressions is aborted with a |
d4f3574e | 8513 | corresponding error message. Expressions may be parenthesised which |
cce74817 | 8514 | causes the evaluation of this expression before any other expression |
d4f3574e | 8515 | which uses the result of the parenthesised expression. The following |
cce74817 | 8516 | operators are supported by @value{GDBN}: |
d4f3574e | 8517 | |
cce74817 JM |
8518 | @table @code |
8519 | @item @code{OR, ORIF, XOR} | |
d4f3574e SS |
8520 | @itemx @code{AND, ANDIF} |
8521 | @itemx @code{NOT} | |
cce74817 | 8522 | Logical operators defined over operands of boolean mode. |
d4f3574e | 8523 | |
cce74817 JM |
8524 | @item @code{=, /=} |
8525 | Equality and inequality operators defined over all modes. | |
d4f3574e | 8526 | |
cce74817 | 8527 | @item @code{>, >=} |
d4f3574e | 8528 | @itemx @code{<, <=} |
cce74817 | 8529 | Relational operators defined over predefined modes. |
d4f3574e | 8530 | |
cce74817 | 8531 | @item @code{+, -} |
d4f3574e | 8532 | @itemx @code{*, /, MOD, REM} |
cce74817 | 8533 | Arithmetic operators defined over predefined modes. |
d4f3574e | 8534 | |
cce74817 JM |
8535 | @item @code{-} |
8536 | Change sign operator. | |
d4f3574e | 8537 | |
cce74817 JM |
8538 | @item @code{//} |
8539 | String concatenation operator. | |
d4f3574e | 8540 | |
cce74817 JM |
8541 | @item @code{()} |
8542 | String repetition operator. | |
d4f3574e | 8543 | |
cce74817 JM |
8544 | @item @code{->} |
8545 | Referenced location operator which can be used either to take the | |
8546 | address of a location (@code{->loc}), or to dereference a reference | |
8547 | location (@code{loc->}). | |
d4f3574e | 8548 | |
cce74817 | 8549 | @item @code{OR, XOR} |
d4f3574e SS |
8550 | @itemx @code{AND} |
8551 | @itemx @code{NOT} | |
cce74817 | 8552 | Powerset and bitstring operators. |
d4f3574e | 8553 | |
cce74817 | 8554 | @item @code{>, >=} |
d4f3574e | 8555 | @itemx @code{<, <=} |
cce74817 | 8556 | Powerset inclusion operators. |
d4f3574e | 8557 | |
cce74817 JM |
8558 | @item @code{IN} |
8559 | Membership operator. | |
8560 | @end table | |
8561 | @end table | |
8562 | ||
6d2ebf8b | 8563 | @node Chill type and range checks |
cce74817 JM |
8564 | @subsubsection Chill type and range checks |
8565 | ||
8566 | @value{GDBN} considers two Chill variables mode equivalent if the sizes | |
d4f3574e | 8567 | of the two modes are equal. This rule applies recursively to more |
cce74817 | 8568 | complex datatypes which means that complex modes are treated |
d4f3574e | 8569 | equivalent if all element modes (which also can be complex modes like |
cce74817 JM |
8570 | structures, arrays, etc.) have the same size. |
8571 | ||
8572 | Range checking is done on all mathematical operations, assignment, array | |
8573 | index bounds and all built in procedures. | |
8574 | ||
8575 | Strong type checks are forced using the @value{GDBN} command @code{set | |
d4f3574e | 8576 | check strong}. This enforces strong type and range checks on all |
cce74817 JM |
8577 | operations where Chill constructs are used (expressions, built in |
8578 | functions, etc.) in respect to the semantics as defined in the z.200 | |
8579 | language specification. | |
8580 | ||
cce74817 JM |
8581 | All checks can be disabled by the @value{GDBN} command @code{set check |
8582 | off}. | |
8583 | ||
5d161b24 | 8584 | @ignore |
53a5351d | 8585 | @c Deviations from the Chill Standard Z200/88 |
cce74817 JM |
8586 | see last paragraph ? |
8587 | @end ignore | |
8588 | ||
6d2ebf8b | 8589 | @node Chill defaults |
cce74817 JM |
8590 | @subsubsection Chill defaults |
8591 | ||
8592 | If type and range checking are set automatically by @value{GDBN}, they | |
8593 | both default to @code{on} whenever the working language changes to | |
d4f3574e | 8594 | Chill. This happens regardless of whether you or @value{GDBN} |
cce74817 JM |
8595 | selected the working language. |
8596 | ||
8597 | If you allow @value{GDBN} to set the language automatically, then entering | |
8598 | code compiled from a file whose name ends with @file{.ch} sets the | |
d4f3574e | 8599 | working language to Chill. @xref{Automatically, ,Having @value{GDBN} set |
cce74817 JM |
8600 | the language automatically}, for further details. |
8601 | ||
6d2ebf8b | 8602 | @node Symbols |
c906108c SS |
8603 | @chapter Examining the Symbol Table |
8604 | ||
d4f3574e | 8605 | The commands described in this chapter allow you to inquire about the |
c906108c SS |
8606 | symbols (names of variables, functions and types) defined in your |
8607 | program. This information is inherent in the text of your program and | |
8608 | does not change as your program executes. @value{GDBN} finds it in your | |
8609 | program's symbol table, in the file indicated when you started @value{GDBN} | |
8610 | (@pxref{File Options, ,Choosing files}), or by one of the | |
8611 | file-management commands (@pxref{Files, ,Commands to specify files}). | |
8612 | ||
8613 | @cindex symbol names | |
8614 | @cindex names of symbols | |
8615 | @cindex quoting names | |
8616 | Occasionally, you may need to refer to symbols that contain unusual | |
8617 | characters, which @value{GDBN} ordinarily treats as word delimiters. The | |
8618 | most frequent case is in referring to static variables in other | |
8619 | source files (@pxref{Variables,,Program variables}). File names | |
8620 | are recorded in object files as debugging symbols, but @value{GDBN} would | |
8621 | ordinarily parse a typical file name, like @file{foo.c}, as the three words | |
8622 | @samp{foo} @samp{.} @samp{c}. To allow @value{GDBN} to recognize | |
8623 | @samp{foo.c} as a single symbol, enclose it in single quotes; for example, | |
8624 | ||
8625 | @example | |
8626 | p 'foo.c'::x | |
8627 | @end example | |
8628 | ||
8629 | @noindent | |
8630 | looks up the value of @code{x} in the scope of the file @file{foo.c}. | |
8631 | ||
8632 | @table @code | |
8633 | @kindex info address | |
b37052ae | 8634 | @cindex address of a symbol |
c906108c SS |
8635 | @item info address @var{symbol} |
8636 | Describe where the data for @var{symbol} is stored. For a register | |
8637 | variable, this says which register it is kept in. For a non-register | |
8638 | local variable, this prints the stack-frame offset at which the variable | |
8639 | is always stored. | |
8640 | ||
8641 | Note the contrast with @samp{print &@var{symbol}}, which does not work | |
8642 | at all for a register variable, and for a stack local variable prints | |
8643 | the exact address of the current instantiation of the variable. | |
8644 | ||
3d67e040 | 8645 | @kindex info symbol |
b37052ae | 8646 | @cindex symbol from address |
3d67e040 EZ |
8647 | @item info symbol @var{addr} |
8648 | Print the name of a symbol which is stored at the address @var{addr}. | |
8649 | If no symbol is stored exactly at @var{addr}, @value{GDBN} prints the | |
8650 | nearest symbol and an offset from it: | |
8651 | ||
8652 | @example | |
8653 | (@value{GDBP}) info symbol 0x54320 | |
8654 | _initialize_vx + 396 in section .text | |
8655 | @end example | |
8656 | ||
8657 | @noindent | |
8658 | This is the opposite of the @code{info address} command. You can use | |
8659 | it to find out the name of a variable or a function given its address. | |
8660 | ||
c906108c | 8661 | @kindex whatis |
d4f3574e SS |
8662 | @item whatis @var{expr} |
8663 | Print the data type of expression @var{expr}. @var{expr} is not | |
c906108c SS |
8664 | actually evaluated, and any side-effecting operations (such as |
8665 | assignments or function calls) inside it do not take place. | |
8666 | @xref{Expressions, ,Expressions}. | |
8667 | ||
8668 | @item whatis | |
8669 | Print the data type of @code{$}, the last value in the value history. | |
8670 | ||
8671 | @kindex ptype | |
8672 | @item ptype @var{typename} | |
8673 | Print a description of data type @var{typename}. @var{typename} may be | |
7a292a7a SS |
8674 | the name of a type, or for C code it may have the form @samp{class |
8675 | @var{class-name}}, @samp{struct @var{struct-tag}}, @samp{union | |
8676 | @var{union-tag}} or @samp{enum @var{enum-tag}}. | |
c906108c | 8677 | |
d4f3574e | 8678 | @item ptype @var{expr} |
c906108c | 8679 | @itemx ptype |
d4f3574e | 8680 | Print a description of the type of expression @var{expr}. @code{ptype} |
c906108c SS |
8681 | differs from @code{whatis} by printing a detailed description, instead |
8682 | of just the name of the type. | |
8683 | ||
8684 | For example, for this variable declaration: | |
8685 | ||
8686 | @example | |
8687 | struct complex @{double real; double imag;@} v; | |
8688 | @end example | |
8689 | ||
8690 | @noindent | |
8691 | the two commands give this output: | |
8692 | ||
8693 | @example | |
8694 | @group | |
8695 | (@value{GDBP}) whatis v | |
8696 | type = struct complex | |
8697 | (@value{GDBP}) ptype v | |
8698 | type = struct complex @{ | |
8699 | double real; | |
8700 | double imag; | |
8701 | @} | |
8702 | @end group | |
8703 | @end example | |
8704 | ||
8705 | @noindent | |
8706 | As with @code{whatis}, using @code{ptype} without an argument refers to | |
8707 | the type of @code{$}, the last value in the value history. | |
8708 | ||
8709 | @kindex info types | |
8710 | @item info types @var{regexp} | |
8711 | @itemx info types | |
d4f3574e | 8712 | Print a brief description of all types whose names match @var{regexp} |
c906108c SS |
8713 | (or all types in your program, if you supply no argument). Each |
8714 | complete typename is matched as though it were a complete line; thus, | |
8715 | @samp{i type value} gives information on all types in your program whose | |
d4f3574e | 8716 | names include the string @code{value}, but @samp{i type ^value$} gives |
c906108c SS |
8717 | information only on types whose complete name is @code{value}. |
8718 | ||
8719 | This command differs from @code{ptype} in two ways: first, like | |
8720 | @code{whatis}, it does not print a detailed description; second, it | |
8721 | lists all source files where a type is defined. | |
8722 | ||
b37052ae EZ |
8723 | @kindex info scope |
8724 | @cindex local variables | |
8725 | @item info scope @var{addr} | |
8726 | List all the variables local to a particular scope. This command | |
8727 | accepts a location---a function name, a source line, or an address | |
8728 | preceded by a @samp{*}, and prints all the variables local to the | |
8729 | scope defined by that location. For example: | |
8730 | ||
8731 | @smallexample | |
8732 | (@value{GDBP}) @b{info scope command_line_handler} | |
8733 | Scope for command_line_handler: | |
8734 | Symbol rl is an argument at stack/frame offset 8, length 4. | |
8735 | Symbol linebuffer is in static storage at address 0x150a18, length 4. | |
8736 | Symbol linelength is in static storage at address 0x150a1c, length 4. | |
8737 | Symbol p is a local variable in register $esi, length 4. | |
8738 | Symbol p1 is a local variable in register $ebx, length 4. | |
8739 | Symbol nline is a local variable in register $edx, length 4. | |
8740 | Symbol repeat is a local variable at frame offset -8, length 4. | |
8741 | @end smallexample | |
8742 | ||
f5c37c66 EZ |
8743 | @noindent |
8744 | This command is especially useful for determining what data to collect | |
8745 | during a @dfn{trace experiment}, see @ref{Tracepoint Actions, | |
8746 | collect}. | |
8747 | ||
c906108c SS |
8748 | @kindex info source |
8749 | @item info source | |
8750 | Show the name of the current source file---that is, the source file for | |
8751 | the function containing the current point of execution---and the language | |
8752 | it was written in. | |
8753 | ||
8754 | @kindex info sources | |
8755 | @item info sources | |
8756 | Print the names of all source files in your program for which there is | |
8757 | debugging information, organized into two lists: files whose symbols | |
8758 | have already been read, and files whose symbols will be read when needed. | |
8759 | ||
8760 | @kindex info functions | |
8761 | @item info functions | |
8762 | Print the names and data types of all defined functions. | |
8763 | ||
8764 | @item info functions @var{regexp} | |
8765 | Print the names and data types of all defined functions | |
8766 | whose names contain a match for regular expression @var{regexp}. | |
8767 | Thus, @samp{info fun step} finds all functions whose names | |
8768 | include @code{step}; @samp{info fun ^step} finds those whose names | |
1c5dfdad MS |
8769 | start with @code{step}. If a function name contains characters |
8770 | that conflict with the regular expression language (eg. | |
8771 | @samp{operator*()}), they may be quoted with a backslash. | |
c906108c SS |
8772 | |
8773 | @kindex info variables | |
8774 | @item info variables | |
8775 | Print the names and data types of all variables that are declared | |
8776 | outside of functions (i.e., excluding local variables). | |
8777 | ||
8778 | @item info variables @var{regexp} | |
8779 | Print the names and data types of all variables (except for local | |
8780 | variables) whose names contain a match for regular expression | |
8781 | @var{regexp}. | |
8782 | ||
8783 | @ignore | |
8784 | This was never implemented. | |
8785 | @kindex info methods | |
8786 | @item info methods | |
8787 | @itemx info methods @var{regexp} | |
8788 | The @code{info methods} command permits the user to examine all defined | |
b37052ae EZ |
8789 | methods within C@t{++} program, or (with the @var{regexp} argument) a |
8790 | specific set of methods found in the various C@t{++} classes. Many | |
8791 | C@t{++} classes provide a large number of methods. Thus, the output | |
c906108c SS |
8792 | from the @code{ptype} command can be overwhelming and hard to use. The |
8793 | @code{info-methods} command filters the methods, printing only those | |
8794 | which match the regular-expression @var{regexp}. | |
8795 | @end ignore | |
8796 | ||
c906108c SS |
8797 | @cindex reloading symbols |
8798 | Some systems allow individual object files that make up your program to | |
7a292a7a SS |
8799 | be replaced without stopping and restarting your program. For example, |
8800 | in VxWorks you can simply recompile a defective object file and keep on | |
8801 | running. If you are running on one of these systems, you can allow | |
8802 | @value{GDBN} to reload the symbols for automatically relinked modules: | |
c906108c SS |
8803 | |
8804 | @table @code | |
8805 | @kindex set symbol-reloading | |
8806 | @item set symbol-reloading on | |
8807 | Replace symbol definitions for the corresponding source file when an | |
8808 | object file with a particular name is seen again. | |
8809 | ||
8810 | @item set symbol-reloading off | |
6d2ebf8b SS |
8811 | Do not replace symbol definitions when encountering object files of the |
8812 | same name more than once. This is the default state; if you are not | |
8813 | running on a system that permits automatic relinking of modules, you | |
8814 | should leave @code{symbol-reloading} off, since otherwise @value{GDBN} | |
8815 | may discard symbols when linking large programs, that may contain | |
8816 | several modules (from different directories or libraries) with the same | |
8817 | name. | |
c906108c SS |
8818 | |
8819 | @kindex show symbol-reloading | |
8820 | @item show symbol-reloading | |
8821 | Show the current @code{on} or @code{off} setting. | |
8822 | @end table | |
c906108c | 8823 | |
c906108c SS |
8824 | @kindex set opaque-type-resolution |
8825 | @item set opaque-type-resolution on | |
8826 | Tell @value{GDBN} to resolve opaque types. An opaque type is a type | |
8827 | declared as a pointer to a @code{struct}, @code{class}, or | |
8828 | @code{union}---for example, @code{struct MyType *}---that is used in one | |
8829 | source file although the full declaration of @code{struct MyType} is in | |
8830 | another source file. The default is on. | |
8831 | ||
8832 | A change in the setting of this subcommand will not take effect until | |
8833 | the next time symbols for a file are loaded. | |
8834 | ||
8835 | @item set opaque-type-resolution off | |
8836 | Tell @value{GDBN} not to resolve opaque types. In this case, the type | |
8837 | is printed as follows: | |
8838 | @smallexample | |
8839 | @{<no data fields>@} | |
8840 | @end smallexample | |
8841 | ||
8842 | @kindex show opaque-type-resolution | |
8843 | @item show opaque-type-resolution | |
8844 | Show whether opaque types are resolved or not. | |
c906108c SS |
8845 | |
8846 | @kindex maint print symbols | |
8847 | @cindex symbol dump | |
8848 | @kindex maint print psymbols | |
8849 | @cindex partial symbol dump | |
8850 | @item maint print symbols @var{filename} | |
8851 | @itemx maint print psymbols @var{filename} | |
8852 | @itemx maint print msymbols @var{filename} | |
8853 | Write a dump of debugging symbol data into the file @var{filename}. | |
8854 | These commands are used to debug the @value{GDBN} symbol-reading code. Only | |
8855 | symbols with debugging data are included. If you use @samp{maint print | |
8856 | symbols}, @value{GDBN} includes all the symbols for which it has already | |
8857 | collected full details: that is, @var{filename} reflects symbols for | |
8858 | only those files whose symbols @value{GDBN} has read. You can use the | |
8859 | command @code{info sources} to find out which files these are. If you | |
8860 | use @samp{maint print psymbols} instead, the dump shows information about | |
8861 | symbols that @value{GDBN} only knows partially---that is, symbols defined in | |
8862 | files that @value{GDBN} has skimmed, but not yet read completely. Finally, | |
8863 | @samp{maint print msymbols} dumps just the minimal symbol information | |
8864 | required for each object file from which @value{GDBN} has read some symbols. | |
8865 | @xref{Files, ,Commands to specify files}, for a discussion of how | |
8866 | @value{GDBN} reads symbols (in the description of @code{symbol-file}). | |
8867 | @end table | |
8868 | ||
6d2ebf8b | 8869 | @node Altering |
c906108c SS |
8870 | @chapter Altering Execution |
8871 | ||
8872 | Once you think you have found an error in your program, you might want to | |
8873 | find out for certain whether correcting the apparent error would lead to | |
8874 | correct results in the rest of the run. You can find the answer by | |
8875 | experiment, using the @value{GDBN} features for altering execution of the | |
8876 | program. | |
8877 | ||
8878 | For example, you can store new values into variables or memory | |
7a292a7a SS |
8879 | locations, give your program a signal, restart it at a different |
8880 | address, or even return prematurely from a function. | |
c906108c SS |
8881 | |
8882 | @menu | |
8883 | * Assignment:: Assignment to variables | |
8884 | * Jumping:: Continuing at a different address | |
c906108c | 8885 | * Signaling:: Giving your program a signal |
c906108c SS |
8886 | * Returning:: Returning from a function |
8887 | * Calling:: Calling your program's functions | |
8888 | * Patching:: Patching your program | |
8889 | @end menu | |
8890 | ||
6d2ebf8b | 8891 | @node Assignment |
c906108c SS |
8892 | @section Assignment to variables |
8893 | ||
8894 | @cindex assignment | |
8895 | @cindex setting variables | |
8896 | To alter the value of a variable, evaluate an assignment expression. | |
8897 | @xref{Expressions, ,Expressions}. For example, | |
8898 | ||
8899 | @example | |
8900 | print x=4 | |
8901 | @end example | |
8902 | ||
8903 | @noindent | |
8904 | stores the value 4 into the variable @code{x}, and then prints the | |
5d161b24 | 8905 | value of the assignment expression (which is 4). |
c906108c SS |
8906 | @xref{Languages, ,Using @value{GDBN} with Different Languages}, for more |
8907 | information on operators in supported languages. | |
c906108c SS |
8908 | |
8909 | @kindex set variable | |
8910 | @cindex variables, setting | |
8911 | If you are not interested in seeing the value of the assignment, use the | |
8912 | @code{set} command instead of the @code{print} command. @code{set} is | |
8913 | really the same as @code{print} except that the expression's value is | |
8914 | not printed and is not put in the value history (@pxref{Value History, | |
8915 | ,Value history}). The expression is evaluated only for its effects. | |
8916 | ||
c906108c SS |
8917 | If the beginning of the argument string of the @code{set} command |
8918 | appears identical to a @code{set} subcommand, use the @code{set | |
8919 | variable} command instead of just @code{set}. This command is identical | |
8920 | to @code{set} except for its lack of subcommands. For example, if your | |
8921 | program has a variable @code{width}, you get an error if you try to set | |
8922 | a new value with just @samp{set width=13}, because @value{GDBN} has the | |
8923 | command @code{set width}: | |
8924 | ||
8925 | @example | |
8926 | (@value{GDBP}) whatis width | |
8927 | type = double | |
8928 | (@value{GDBP}) p width | |
8929 | $4 = 13 | |
8930 | (@value{GDBP}) set width=47 | |
8931 | Invalid syntax in expression. | |
8932 | @end example | |
8933 | ||
8934 | @noindent | |
8935 | The invalid expression, of course, is @samp{=47}. In | |
8936 | order to actually set the program's variable @code{width}, use | |
8937 | ||
8938 | @example | |
8939 | (@value{GDBP}) set var width=47 | |
8940 | @end example | |
53a5351d | 8941 | |
c906108c SS |
8942 | Because the @code{set} command has many subcommands that can conflict |
8943 | with the names of program variables, it is a good idea to use the | |
8944 | @code{set variable} command instead of just @code{set}. For example, if | |
8945 | your program has a variable @code{g}, you run into problems if you try | |
8946 | to set a new value with just @samp{set g=4}, because @value{GDBN} has | |
8947 | the command @code{set gnutarget}, abbreviated @code{set g}: | |
8948 | ||
8949 | @example | |
8950 | @group | |
8951 | (@value{GDBP}) whatis g | |
8952 | type = double | |
8953 | (@value{GDBP}) p g | |
8954 | $1 = 1 | |
8955 | (@value{GDBP}) set g=4 | |
2df3850c | 8956 | (@value{GDBP}) p g |
c906108c SS |
8957 | $2 = 1 |
8958 | (@value{GDBP}) r | |
8959 | The program being debugged has been started already. | |
8960 | Start it from the beginning? (y or n) y | |
8961 | Starting program: /home/smith/cc_progs/a.out | |
6d2ebf8b SS |
8962 | "/home/smith/cc_progs/a.out": can't open to read symbols: |
8963 | Invalid bfd target. | |
c906108c SS |
8964 | (@value{GDBP}) show g |
8965 | The current BFD target is "=4". | |
8966 | @end group | |
8967 | @end example | |
8968 | ||
8969 | @noindent | |
8970 | The program variable @code{g} did not change, and you silently set the | |
8971 | @code{gnutarget} to an invalid value. In order to set the variable | |
8972 | @code{g}, use | |
8973 | ||
8974 | @example | |
8975 | (@value{GDBP}) set var g=4 | |
8976 | @end example | |
c906108c SS |
8977 | |
8978 | @value{GDBN} allows more implicit conversions in assignments than C; you can | |
8979 | freely store an integer value into a pointer variable or vice versa, | |
8980 | and you can convert any structure to any other structure that is the | |
8981 | same length or shorter. | |
8982 | @comment FIXME: how do structs align/pad in these conversions? | |
8983 | @comment /doc@cygnus.com 18dec1990 | |
8984 | ||
8985 | To store values into arbitrary places in memory, use the @samp{@{@dots{}@}} | |
8986 | construct to generate a value of specified type at a specified address | |
8987 | (@pxref{Expressions, ,Expressions}). For example, @code{@{int@}0x83040} refers | |
8988 | to memory location @code{0x83040} as an integer (which implies a certain size | |
8989 | and representation in memory), and | |
8990 | ||
8991 | @example | |
8992 | set @{int@}0x83040 = 4 | |
8993 | @end example | |
8994 | ||
8995 | @noindent | |
8996 | stores the value 4 into that memory location. | |
8997 | ||
6d2ebf8b | 8998 | @node Jumping |
c906108c SS |
8999 | @section Continuing at a different address |
9000 | ||
9001 | Ordinarily, when you continue your program, you do so at the place where | |
9002 | it stopped, with the @code{continue} command. You can instead continue at | |
9003 | an address of your own choosing, with the following commands: | |
9004 | ||
9005 | @table @code | |
9006 | @kindex jump | |
9007 | @item jump @var{linespec} | |
9008 | Resume execution at line @var{linespec}. Execution stops again | |
9009 | immediately if there is a breakpoint there. @xref{List, ,Printing | |
9010 | source lines}, for a description of the different forms of | |
9011 | @var{linespec}. It is common practice to use the @code{tbreak} command | |
9012 | in conjunction with @code{jump}. @xref{Set Breaks, ,Setting | |
9013 | breakpoints}. | |
9014 | ||
9015 | The @code{jump} command does not change the current stack frame, or | |
9016 | the stack pointer, or the contents of any memory location or any | |
9017 | register other than the program counter. If line @var{linespec} is in | |
9018 | a different function from the one currently executing, the results may | |
9019 | be bizarre if the two functions expect different patterns of arguments or | |
9020 | of local variables. For this reason, the @code{jump} command requests | |
9021 | confirmation if the specified line is not in the function currently | |
9022 | executing. However, even bizarre results are predictable if you are | |
9023 | well acquainted with the machine-language code of your program. | |
9024 | ||
9025 | @item jump *@var{address} | |
9026 | Resume execution at the instruction at address @var{address}. | |
9027 | @end table | |
9028 | ||
c906108c | 9029 | @c Doesn't work on HP-UX; have to set $pcoqh and $pcoqt. |
53a5351d JM |
9030 | On many systems, you can get much the same effect as the @code{jump} |
9031 | command by storing a new value into the register @code{$pc}. The | |
9032 | difference is that this does not start your program running; it only | |
9033 | changes the address of where it @emph{will} run when you continue. For | |
9034 | example, | |
c906108c SS |
9035 | |
9036 | @example | |
9037 | set $pc = 0x485 | |
9038 | @end example | |
9039 | ||
9040 | @noindent | |
9041 | makes the next @code{continue} command or stepping command execute at | |
9042 | address @code{0x485}, rather than at the address where your program stopped. | |
9043 | @xref{Continuing and Stepping, ,Continuing and stepping}. | |
c906108c SS |
9044 | |
9045 | The most common occasion to use the @code{jump} command is to back | |
9046 | up---perhaps with more breakpoints set---over a portion of a program | |
9047 | that has already executed, in order to examine its execution in more | |
9048 | detail. | |
9049 | ||
c906108c | 9050 | @c @group |
6d2ebf8b | 9051 | @node Signaling |
c906108c SS |
9052 | @section Giving your program a signal |
9053 | ||
9054 | @table @code | |
9055 | @kindex signal | |
9056 | @item signal @var{signal} | |
9057 | Resume execution where your program stopped, but immediately give it the | |
9058 | signal @var{signal}. @var{signal} can be the name or the number of a | |
9059 | signal. For example, on many systems @code{signal 2} and @code{signal | |
9060 | SIGINT} are both ways of sending an interrupt signal. | |
9061 | ||
9062 | Alternatively, if @var{signal} is zero, continue execution without | |
9063 | giving a signal. This is useful when your program stopped on account of | |
9064 | a signal and would ordinary see the signal when resumed with the | |
9065 | @code{continue} command; @samp{signal 0} causes it to resume without a | |
9066 | signal. | |
9067 | ||
9068 | @code{signal} does not repeat when you press @key{RET} a second time | |
9069 | after executing the command. | |
9070 | @end table | |
9071 | @c @end group | |
9072 | ||
9073 | Invoking the @code{signal} command is not the same as invoking the | |
9074 | @code{kill} utility from the shell. Sending a signal with @code{kill} | |
9075 | causes @value{GDBN} to decide what to do with the signal depending on | |
9076 | the signal handling tables (@pxref{Signals}). The @code{signal} command | |
9077 | passes the signal directly to your program. | |
9078 | ||
c906108c | 9079 | |
6d2ebf8b | 9080 | @node Returning |
c906108c SS |
9081 | @section Returning from a function |
9082 | ||
9083 | @table @code | |
9084 | @cindex returning from a function | |
9085 | @kindex return | |
9086 | @item return | |
9087 | @itemx return @var{expression} | |
9088 | You can cancel execution of a function call with the @code{return} | |
9089 | command. If you give an | |
9090 | @var{expression} argument, its value is used as the function's return | |
9091 | value. | |
9092 | @end table | |
9093 | ||
9094 | When you use @code{return}, @value{GDBN} discards the selected stack frame | |
9095 | (and all frames within it). You can think of this as making the | |
9096 | discarded frame return prematurely. If you wish to specify a value to | |
9097 | be returned, give that value as the argument to @code{return}. | |
9098 | ||
9099 | This pops the selected stack frame (@pxref{Selection, ,Selecting a | |
9100 | frame}), and any other frames inside of it, leaving its caller as the | |
9101 | innermost remaining frame. That frame becomes selected. The | |
9102 | specified value is stored in the registers used for returning values | |
9103 | of functions. | |
9104 | ||
9105 | The @code{return} command does not resume execution; it leaves the | |
9106 | program stopped in the state that would exist if the function had just | |
9107 | returned. In contrast, the @code{finish} command (@pxref{Continuing | |
9108 | and Stepping, ,Continuing and stepping}) resumes execution until the | |
9109 | selected stack frame returns naturally. | |
9110 | ||
6d2ebf8b | 9111 | @node Calling |
c906108c SS |
9112 | @section Calling program functions |
9113 | ||
9114 | @cindex calling functions | |
9115 | @kindex call | |
9116 | @table @code | |
9117 | @item call @var{expr} | |
9118 | Evaluate the expression @var{expr} without displaying @code{void} | |
9119 | returned values. | |
9120 | @end table | |
9121 | ||
9122 | You can use this variant of the @code{print} command if you want to | |
9123 | execute a function from your program, but without cluttering the output | |
5d161b24 DB |
9124 | with @code{void} returned values. If the result is not void, it |
9125 | is printed and saved in the value history. | |
c906108c | 9126 | |
7d86b5d5 AC |
9127 | @c OBSOLETE For the A29K, a user-controlled variable @code{call_scratch_address}, |
9128 | @c OBSOLETE specifies the location of a scratch area to be used when @value{GDBN} | |
9129 | @c OBSOLETE calls a function in the target. This is necessary because the usual | |
9130 | @c OBSOLETE method of putting the scratch area on the stack does not work in systems | |
9131 | @c OBSOLETE that have separate instruction and data spaces. | |
c906108c | 9132 | |
6d2ebf8b | 9133 | @node Patching |
c906108c | 9134 | @section Patching programs |
7a292a7a | 9135 | |
c906108c SS |
9136 | @cindex patching binaries |
9137 | @cindex writing into executables | |
c906108c | 9138 | @cindex writing into corefiles |
c906108c | 9139 | |
7a292a7a SS |
9140 | By default, @value{GDBN} opens the file containing your program's |
9141 | executable code (or the corefile) read-only. This prevents accidental | |
9142 | alterations to machine code; but it also prevents you from intentionally | |
9143 | patching your program's binary. | |
c906108c SS |
9144 | |
9145 | If you'd like to be able to patch the binary, you can specify that | |
9146 | explicitly with the @code{set write} command. For example, you might | |
9147 | want to turn on internal debugging flags, or even to make emergency | |
9148 | repairs. | |
9149 | ||
9150 | @table @code | |
9151 | @kindex set write | |
9152 | @item set write on | |
9153 | @itemx set write off | |
7a292a7a SS |
9154 | If you specify @samp{set write on}, @value{GDBN} opens executable and |
9155 | core files for both reading and writing; if you specify @samp{set write | |
c906108c SS |
9156 | off} (the default), @value{GDBN} opens them read-only. |
9157 | ||
9158 | If you have already loaded a file, you must load it again (using the | |
7a292a7a SS |
9159 | @code{exec-file} or @code{core-file} command) after changing @code{set |
9160 | write}, for your new setting to take effect. | |
c906108c SS |
9161 | |
9162 | @item show write | |
9163 | @kindex show write | |
7a292a7a SS |
9164 | Display whether executable files and core files are opened for writing |
9165 | as well as reading. | |
c906108c SS |
9166 | @end table |
9167 | ||
6d2ebf8b | 9168 | @node GDB Files |
c906108c SS |
9169 | @chapter @value{GDBN} Files |
9170 | ||
7a292a7a SS |
9171 | @value{GDBN} needs to know the file name of the program to be debugged, |
9172 | both in order to read its symbol table and in order to start your | |
9173 | program. To debug a core dump of a previous run, you must also tell | |
9174 | @value{GDBN} the name of the core dump file. | |
c906108c SS |
9175 | |
9176 | @menu | |
9177 | * Files:: Commands to specify files | |
9178 | * Symbol Errors:: Errors reading symbol files | |
9179 | @end menu | |
9180 | ||
6d2ebf8b | 9181 | @node Files |
c906108c | 9182 | @section Commands to specify files |
c906108c | 9183 | |
7a292a7a | 9184 | @cindex symbol table |
c906108c | 9185 | @cindex core dump file |
7a292a7a SS |
9186 | |
9187 | You may want to specify executable and core dump file names. The usual | |
9188 | way to do this is at start-up time, using the arguments to | |
9189 | @value{GDBN}'s start-up commands (@pxref{Invocation, , Getting In and | |
9190 | Out of @value{GDBN}}). | |
c906108c SS |
9191 | |
9192 | Occasionally it is necessary to change to a different file during a | |
9193 | @value{GDBN} session. Or you may run @value{GDBN} and forget to specify | |
9194 | a file you want to use. In these situations the @value{GDBN} commands | |
9195 | to specify new files are useful. | |
9196 | ||
9197 | @table @code | |
9198 | @cindex executable file | |
9199 | @kindex file | |
9200 | @item file @var{filename} | |
9201 | Use @var{filename} as the program to be debugged. It is read for its | |
9202 | symbols and for the contents of pure memory. It is also the program | |
9203 | executed when you use the @code{run} command. If you do not specify a | |
5d161b24 DB |
9204 | directory and the file is not found in the @value{GDBN} working directory, |
9205 | @value{GDBN} uses the environment variable @code{PATH} as a list of | |
9206 | directories to search, just as the shell does when looking for a program | |
9207 | to run. You can change the value of this variable, for both @value{GDBN} | |
c906108c SS |
9208 | and your program, using the @code{path} command. |
9209 | ||
6d2ebf8b | 9210 | On systems with memory-mapped files, an auxiliary file named |
c906108c SS |
9211 | @file{@var{filename}.syms} may hold symbol table information for |
9212 | @var{filename}. If so, @value{GDBN} maps in the symbol table from | |
9213 | @file{@var{filename}.syms}, starting up more quickly. See the | |
9214 | descriptions of the file options @samp{-mapped} and @samp{-readnow} | |
9215 | (available on the command line, and with the commands @code{file}, | |
5d161b24 | 9216 | @code{symbol-file}, or @code{add-symbol-file}, described below), |
c906108c | 9217 | for more information. |
c906108c SS |
9218 | |
9219 | @item file | |
9220 | @code{file} with no argument makes @value{GDBN} discard any information it | |
9221 | has on both executable file and the symbol table. | |
9222 | ||
9223 | @kindex exec-file | |
9224 | @item exec-file @r{[} @var{filename} @r{]} | |
9225 | Specify that the program to be run (but not the symbol table) is found | |
9226 | in @var{filename}. @value{GDBN} searches the environment variable @code{PATH} | |
9227 | if necessary to locate your program. Omitting @var{filename} means to | |
9228 | discard information on the executable file. | |
9229 | ||
9230 | @kindex symbol-file | |
9231 | @item symbol-file @r{[} @var{filename} @r{]} | |
9232 | Read symbol table information from file @var{filename}. @code{PATH} is | |
9233 | searched when necessary. Use the @code{file} command to get both symbol | |
9234 | table and program to run from the same file. | |
9235 | ||
9236 | @code{symbol-file} with no argument clears out @value{GDBN} information on your | |
9237 | program's symbol table. | |
9238 | ||
5d161b24 | 9239 | The @code{symbol-file} command causes @value{GDBN} to forget the contents |
c906108c SS |
9240 | of its convenience variables, the value history, and all breakpoints and |
9241 | auto-display expressions. This is because they may contain pointers to | |
9242 | the internal data recording symbols and data types, which are part of | |
9243 | the old symbol table data being discarded inside @value{GDBN}. | |
9244 | ||
9245 | @code{symbol-file} does not repeat if you press @key{RET} again after | |
9246 | executing it once. | |
9247 | ||
9248 | When @value{GDBN} is configured for a particular environment, it | |
9249 | understands debugging information in whatever format is the standard | |
9250 | generated for that environment; you may use either a @sc{gnu} compiler, or | |
9251 | other compilers that adhere to the local conventions. | |
c906108c SS |
9252 | Best results are usually obtained from @sc{gnu} compilers; for example, |
9253 | using @code{@value{GCC}} you can generate debugging information for | |
9254 | optimized code. | |
c906108c SS |
9255 | |
9256 | For most kinds of object files, with the exception of old SVR3 systems | |
9257 | using COFF, the @code{symbol-file} command does not normally read the | |
9258 | symbol table in full right away. Instead, it scans the symbol table | |
9259 | quickly to find which source files and which symbols are present. The | |
9260 | details are read later, one source file at a time, as they are needed. | |
9261 | ||
9262 | The purpose of this two-stage reading strategy is to make @value{GDBN} | |
9263 | start up faster. For the most part, it is invisible except for | |
9264 | occasional pauses while the symbol table details for a particular source | |
9265 | file are being read. (The @code{set verbose} command can turn these | |
9266 | pauses into messages if desired. @xref{Messages/Warnings, ,Optional | |
9267 | warnings and messages}.) | |
9268 | ||
c906108c SS |
9269 | We have not implemented the two-stage strategy for COFF yet. When the |
9270 | symbol table is stored in COFF format, @code{symbol-file} reads the | |
9271 | symbol table data in full right away. Note that ``stabs-in-COFF'' | |
9272 | still does the two-stage strategy, since the debug info is actually | |
9273 | in stabs format. | |
9274 | ||
9275 | @kindex readnow | |
9276 | @cindex reading symbols immediately | |
9277 | @cindex symbols, reading immediately | |
9278 | @kindex mapped | |
9279 | @cindex memory-mapped symbol file | |
9280 | @cindex saving symbol table | |
9281 | @item symbol-file @var{filename} @r{[} -readnow @r{]} @r{[} -mapped @r{]} | |
9282 | @itemx file @var{filename} @r{[} -readnow @r{]} @r{[} -mapped @r{]} | |
9283 | You can override the @value{GDBN} two-stage strategy for reading symbol | |
9284 | tables by using the @samp{-readnow} option with any of the commands that | |
9285 | load symbol table information, if you want to be sure @value{GDBN} has the | |
5d161b24 | 9286 | entire symbol table available. |
c906108c | 9287 | |
c906108c SS |
9288 | If memory-mapped files are available on your system through the |
9289 | @code{mmap} system call, you can use another option, @samp{-mapped}, to | |
9290 | cause @value{GDBN} to write the symbols for your program into a reusable | |
9291 | file. Future @value{GDBN} debugging sessions map in symbol information | |
9292 | from this auxiliary symbol file (if the program has not changed), rather | |
9293 | than spending time reading the symbol table from the executable | |
9294 | program. Using the @samp{-mapped} option has the same effect as | |
9295 | starting @value{GDBN} with the @samp{-mapped} command-line option. | |
9296 | ||
9297 | You can use both options together, to make sure the auxiliary symbol | |
9298 | file has all the symbol information for your program. | |
9299 | ||
9300 | The auxiliary symbol file for a program called @var{myprog} is called | |
9301 | @samp{@var{myprog}.syms}. Once this file exists (so long as it is newer | |
9302 | than the corresponding executable), @value{GDBN} always attempts to use | |
9303 | it when you debug @var{myprog}; no special options or commands are | |
9304 | needed. | |
9305 | ||
9306 | The @file{.syms} file is specific to the host machine where you run | |
9307 | @value{GDBN}. It holds an exact image of the internal @value{GDBN} | |
9308 | symbol table. It cannot be shared across multiple host platforms. | |
c906108c SS |
9309 | |
9310 | @c FIXME: for now no mention of directories, since this seems to be in | |
9311 | @c flux. 13mar1992 status is that in theory GDB would look either in | |
9312 | @c current dir or in same dir as myprog; but issues like competing | |
9313 | @c GDB's, or clutter in system dirs, mean that in practice right now | |
9314 | @c only current dir is used. FFish says maybe a special GDB hierarchy | |
9315 | @c (eg rooted in val of env var GDBSYMS) could exist for mappable symbol | |
9316 | @c files. | |
9317 | ||
9318 | @kindex core | |
9319 | @kindex core-file | |
9320 | @item core-file @r{[} @var{filename} @r{]} | |
9321 | Specify the whereabouts of a core dump file to be used as the ``contents | |
9322 | of memory''. Traditionally, core files contain only some parts of the | |
9323 | address space of the process that generated them; @value{GDBN} can access the | |
9324 | executable file itself for other parts. | |
9325 | ||
9326 | @code{core-file} with no argument specifies that no core file is | |
9327 | to be used. | |
9328 | ||
9329 | Note that the core file is ignored when your program is actually running | |
7a292a7a SS |
9330 | under @value{GDBN}. So, if you have been running your program and you |
9331 | wish to debug a core file instead, you must kill the subprocess in which | |
9332 | the program is running. To do this, use the @code{kill} command | |
c906108c | 9333 | (@pxref{Kill Process, ,Killing the child process}). |
c906108c | 9334 | |
c906108c SS |
9335 | @kindex add-symbol-file |
9336 | @cindex dynamic linking | |
9337 | @item add-symbol-file @var{filename} @var{address} | |
9338 | @itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]} @r{[} -mapped @r{]} | |
17d9d558 | 9339 | @itemx add-symbol-file @var{filename} @r{-s}@var{section} @var{address} @dots{} |
96a2c332 SS |
9340 | The @code{add-symbol-file} command reads additional symbol table |
9341 | information from the file @var{filename}. You would use this command | |
9342 | when @var{filename} has been dynamically loaded (by some other means) | |
9343 | into the program that is running. @var{address} should be the memory | |
9344 | address at which the file has been loaded; @value{GDBN} cannot figure | |
d167840f EZ |
9345 | this out for itself. You can additionally specify an arbitrary number |
9346 | of @samp{@r{-s}@var{section} @var{address}} pairs, to give an explicit | |
9347 | section name and base address for that section. You can specify any | |
9348 | @var{address} as an expression. | |
c906108c SS |
9349 | |
9350 | The symbol table of the file @var{filename} is added to the symbol table | |
9351 | originally read with the @code{symbol-file} command. You can use the | |
96a2c332 SS |
9352 | @code{add-symbol-file} command any number of times; the new symbol data |
9353 | thus read keeps adding to the old. To discard all old symbol data | |
9354 | instead, use the @code{symbol-file} command without any arguments. | |
c906108c | 9355 | |
17d9d558 JB |
9356 | @cindex relocatable object files, reading symbols from |
9357 | @cindex object files, relocatable, reading symbols from | |
9358 | @cindex reading symbols from relocatable object files | |
9359 | @cindex symbols, reading from relocatable object files | |
9360 | @cindex @file{.o} files, reading symbols from | |
9361 | Although @var{filename} is typically a shared library file, an | |
9362 | executable file, or some other object file which has been fully | |
9363 | relocated for loading into a process, you can also load symbolic | |
9364 | information from relocatable @file{.o} files, as long as: | |
9365 | ||
9366 | @itemize @bullet | |
9367 | @item | |
9368 | the file's symbolic information refers only to linker symbols defined in | |
9369 | that file, not to symbols defined by other object files, | |
9370 | @item | |
9371 | every section the file's symbolic information refers to has actually | |
9372 | been loaded into the inferior, as it appears in the file, and | |
9373 | @item | |
9374 | you can determine the address at which every section was loaded, and | |
9375 | provide these to the @code{add-symbol-file} command. | |
9376 | @end itemize | |
9377 | ||
9378 | @noindent | |
9379 | Some embedded operating systems, like Sun Chorus and VxWorks, can load | |
9380 | relocatable files into an already running program; such systems | |
9381 | typically make the requirements above easy to meet. However, it's | |
9382 | important to recognize that many native systems use complex link | |
9383 | procedures (@code{.linkonce} section factoring and C++ constructor table | |
9384 | assembly, for example) that make the requirements difficult to meet. In | |
9385 | general, one cannot assume that using @code{add-symbol-file} to read a | |
9386 | relocatable object file's symbolic information will have the same effect | |
9387 | as linking the relocatable object file into the program in the normal | |
9388 | way. | |
9389 | ||
c906108c SS |
9390 | @code{add-symbol-file} does not repeat if you press @key{RET} after using it. |
9391 | ||
9392 | You can use the @samp{-mapped} and @samp{-readnow} options just as with | |
9393 | the @code{symbol-file} command, to change how @value{GDBN} manages the symbol | |
9394 | table information for @var{filename}. | |
9395 | ||
9396 | @kindex add-shared-symbol-file | |
9397 | @item add-shared-symbol-file | |
9398 | The @code{add-shared-symbol-file} command can be used only under Harris' CXUX | |
5d161b24 DB |
9399 | operating system for the Motorola 88k. @value{GDBN} automatically looks for |
9400 | shared libraries, however if @value{GDBN} does not find yours, you can run | |
c906108c | 9401 | @code{add-shared-symbol-file}. It takes no arguments. |
c906108c | 9402 | |
c906108c SS |
9403 | @kindex section |
9404 | @item section | |
5d161b24 DB |
9405 | The @code{section} command changes the base address of section SECTION of |
9406 | the exec file to ADDR. This can be used if the exec file does not contain | |
9407 | section addresses, (such as in the a.out format), or when the addresses | |
9408 | specified in the file itself are wrong. Each section must be changed | |
d4f3574e SS |
9409 | separately. The @code{info files} command, described below, lists all |
9410 | the sections and their addresses. | |
c906108c SS |
9411 | |
9412 | @kindex info files | |
9413 | @kindex info target | |
9414 | @item info files | |
9415 | @itemx info target | |
7a292a7a SS |
9416 | @code{info files} and @code{info target} are synonymous; both print the |
9417 | current target (@pxref{Targets, ,Specifying a Debugging Target}), | |
9418 | including the names of the executable and core dump files currently in | |
9419 | use by @value{GDBN}, and the files from which symbols were loaded. The | |
9420 | command @code{help target} lists all possible targets rather than | |
9421 | current ones. | |
9422 | ||
fe95c787 MS |
9423 | @kindex maint info sections |
9424 | @item maint info sections | |
9425 | Another command that can give you extra information about program sections | |
9426 | is @code{maint info sections}. In addition to the section information | |
9427 | displayed by @code{info files}, this command displays the flags and file | |
9428 | offset of each section in the executable and core dump files. In addition, | |
9429 | @code{maint info sections} provides the following command options (which | |
9430 | may be arbitrarily combined): | |
9431 | ||
9432 | @table @code | |
9433 | @item ALLOBJ | |
9434 | Display sections for all loaded object files, including shared libraries. | |
9435 | @item @var{sections} | |
6600abed | 9436 | Display info only for named @var{sections}. |
fe95c787 MS |
9437 | @item @var{section-flags} |
9438 | Display info only for sections for which @var{section-flags} are true. | |
9439 | The section flags that @value{GDBN} currently knows about are: | |
9440 | @table @code | |
9441 | @item ALLOC | |
9442 | Section will have space allocated in the process when loaded. | |
9443 | Set for all sections except those containing debug information. | |
9444 | @item LOAD | |
9445 | Section will be loaded from the file into the child process memory. | |
9446 | Set for pre-initialized code and data, clear for @code{.bss} sections. | |
9447 | @item RELOC | |
9448 | Section needs to be relocated before loading. | |
9449 | @item READONLY | |
9450 | Section cannot be modified by the child process. | |
9451 | @item CODE | |
9452 | Section contains executable code only. | |
6600abed | 9453 | @item DATA |
fe95c787 MS |
9454 | Section contains data only (no executable code). |
9455 | @item ROM | |
9456 | Section will reside in ROM. | |
9457 | @item CONSTRUCTOR | |
9458 | Section contains data for constructor/destructor lists. | |
9459 | @item HAS_CONTENTS | |
9460 | Section is not empty. | |
9461 | @item NEVER_LOAD | |
9462 | An instruction to the linker to not output the section. | |
9463 | @item COFF_SHARED_LIBRARY | |
9464 | A notification to the linker that the section contains | |
9465 | COFF shared library information. | |
9466 | @item IS_COMMON | |
9467 | Section contains common symbols. | |
9468 | @end table | |
9469 | @end table | |
c906108c SS |
9470 | @end table |
9471 | ||
9472 | All file-specifying commands allow both absolute and relative file names | |
9473 | as arguments. @value{GDBN} always converts the file name to an absolute file | |
9474 | name and remembers it that way. | |
9475 | ||
c906108c | 9476 | @cindex shared libraries |
c906108c SS |
9477 | @value{GDBN} supports HP-UX, SunOS, SVr4, Irix 5, and IBM RS/6000 shared |
9478 | libraries. | |
53a5351d | 9479 | |
c906108c SS |
9480 | @value{GDBN} automatically loads symbol definitions from shared libraries |
9481 | when you use the @code{run} command, or when you examine a core file. | |
9482 | (Before you issue the @code{run} command, @value{GDBN} does not understand | |
9483 | references to a function in a shared library, however---unless you are | |
9484 | debugging a core file). | |
53a5351d JM |
9485 | |
9486 | On HP-UX, if the program loads a library explicitly, @value{GDBN} | |
9487 | automatically loads the symbols at the time of the @code{shl_load} call. | |
9488 | ||
c906108c SS |
9489 | @c FIXME: some @value{GDBN} release may permit some refs to undef |
9490 | @c FIXME...symbols---eg in a break cmd---assuming they are from a shared | |
9491 | @c FIXME...lib; check this from time to time when updating manual | |
9492 | ||
b7209cb4 FF |
9493 | There are times, however, when you may wish to not automatically load |
9494 | symbol definitions from shared libraries, such as when they are | |
9495 | particularly large or there are many of them. | |
9496 | ||
9497 | To control the automatic loading of shared library symbols, use the | |
9498 | commands: | |
9499 | ||
9500 | @table @code | |
9501 | @kindex set auto-solib-add | |
9502 | @item set auto-solib-add @var{mode} | |
9503 | If @var{mode} is @code{on}, symbols from all shared object libraries | |
9504 | will be loaded automatically when the inferior begins execution, you | |
9505 | attach to an independently started inferior, or when the dynamic linker | |
9506 | informs @value{GDBN} that a new library has been loaded. If @var{mode} | |
9507 | is @code{off}, symbols must be loaded manually, using the | |
9508 | @code{sharedlibrary} command. The default value is @code{on}. | |
9509 | ||
9510 | @kindex show auto-solib-add | |
9511 | @item show auto-solib-add | |
9512 | Display the current autoloading mode. | |
9513 | @end table | |
9514 | ||
9515 | To explicitly load shared library symbols, use the @code{sharedlibrary} | |
9516 | command: | |
9517 | ||
c906108c SS |
9518 | @table @code |
9519 | @kindex info sharedlibrary | |
9520 | @kindex info share | |
9521 | @item info share | |
9522 | @itemx info sharedlibrary | |
9523 | Print the names of the shared libraries which are currently loaded. | |
9524 | ||
9525 | @kindex sharedlibrary | |
9526 | @kindex share | |
9527 | @item sharedlibrary @var{regex} | |
9528 | @itemx share @var{regex} | |
c906108c SS |
9529 | Load shared object library symbols for files matching a |
9530 | Unix regular expression. | |
9531 | As with files loaded automatically, it only loads shared libraries | |
9532 | required by your program for a core file or after typing @code{run}. If | |
9533 | @var{regex} is omitted all shared libraries required by your program are | |
9534 | loaded. | |
9535 | @end table | |
9536 | ||
b7209cb4 FF |
9537 | On some systems, such as HP-UX systems, @value{GDBN} supports |
9538 | autoloading shared library symbols until a limiting threshold size is | |
9539 | reached. This provides the benefit of allowing autoloading to remain on | |
9540 | by default, but avoids autoloading excessively large shared libraries, | |
9541 | up to a threshold that is initially set, but which you can modify if you | |
9542 | wish. | |
c906108c SS |
9543 | |
9544 | Beyond that threshold, symbols from shared libraries must be explicitly | |
d4f3574e SS |
9545 | loaded. To load these symbols, use the command @code{sharedlibrary |
9546 | @var{filename}}. The base address of the shared library is determined | |
c906108c SS |
9547 | automatically by @value{GDBN} and need not be specified. |
9548 | ||
9549 | To display or set the threshold, use the commands: | |
9550 | ||
9551 | @table @code | |
b7209cb4 FF |
9552 | @kindex set auto-solib-limit |
9553 | @item set auto-solib-limit @var{threshold} | |
9554 | Set the autoloading size threshold, in an integral number of megabytes. | |
9555 | If @var{threshold} is nonzero and shared library autoloading is enabled, | |
9556 | symbols from all shared object libraries will be loaded until the total | |
9557 | size of the loaded shared library symbols exceeds this threshold. | |
c906108c | 9558 | Otherwise, symbols must be loaded manually, using the |
b7209cb4 FF |
9559 | @code{sharedlibrary} command. The default threshold is 100 (i.e. 100 |
9560 | Mb). | |
c906108c | 9561 | |
b7209cb4 FF |
9562 | @kindex show auto-solib-limit |
9563 | @item show auto-solib-limit | |
c906108c SS |
9564 | Display the current autoloading size threshold, in megabytes. |
9565 | @end table | |
c906108c | 9566 | |
6d2ebf8b | 9567 | @node Symbol Errors |
c906108c SS |
9568 | @section Errors reading symbol files |
9569 | ||
9570 | While reading a symbol file, @value{GDBN} occasionally encounters problems, | |
9571 | such as symbol types it does not recognize, or known bugs in compiler | |
9572 | output. By default, @value{GDBN} does not notify you of such problems, since | |
9573 | they are relatively common and primarily of interest to people | |
9574 | debugging compilers. If you are interested in seeing information | |
9575 | about ill-constructed symbol tables, you can either ask @value{GDBN} to print | |
9576 | only one message about each such type of problem, no matter how many | |
9577 | times the problem occurs; or you can ask @value{GDBN} to print more messages, | |
9578 | to see how many times the problems occur, with the @code{set | |
9579 | complaints} command (@pxref{Messages/Warnings, ,Optional warnings and | |
9580 | messages}). | |
9581 | ||
9582 | The messages currently printed, and their meanings, include: | |
9583 | ||
9584 | @table @code | |
9585 | @item inner block not inside outer block in @var{symbol} | |
9586 | ||
9587 | The symbol information shows where symbol scopes begin and end | |
9588 | (such as at the start of a function or a block of statements). This | |
9589 | error indicates that an inner scope block is not fully contained | |
9590 | in its outer scope blocks. | |
9591 | ||
9592 | @value{GDBN} circumvents the problem by treating the inner block as if it had | |
9593 | the same scope as the outer block. In the error message, @var{symbol} | |
9594 | may be shown as ``@code{(don't know)}'' if the outer block is not a | |
9595 | function. | |
9596 | ||
9597 | @item block at @var{address} out of order | |
9598 | ||
9599 | The symbol information for symbol scope blocks should occur in | |
9600 | order of increasing addresses. This error indicates that it does not | |
9601 | do so. | |
9602 | ||
9603 | @value{GDBN} does not circumvent this problem, and has trouble | |
9604 | locating symbols in the source file whose symbols it is reading. (You | |
9605 | can often determine what source file is affected by specifying | |
9606 | @code{set verbose on}. @xref{Messages/Warnings, ,Optional warnings and | |
9607 | messages}.) | |
9608 | ||
9609 | @item bad block start address patched | |
9610 | ||
9611 | The symbol information for a symbol scope block has a start address | |
9612 | smaller than the address of the preceding source line. This is known | |
9613 | to occur in the SunOS 4.1.1 (and earlier) C compiler. | |
9614 | ||
9615 | @value{GDBN} circumvents the problem by treating the symbol scope block as | |
9616 | starting on the previous source line. | |
9617 | ||
9618 | @item bad string table offset in symbol @var{n} | |
9619 | ||
9620 | @cindex foo | |
9621 | Symbol number @var{n} contains a pointer into the string table which is | |
9622 | larger than the size of the string table. | |
9623 | ||
9624 | @value{GDBN} circumvents the problem by considering the symbol to have the | |
9625 | name @code{foo}, which may cause other problems if many symbols end up | |
9626 | with this name. | |
9627 | ||
9628 | @item unknown symbol type @code{0x@var{nn}} | |
9629 | ||
7a292a7a SS |
9630 | The symbol information contains new data types that @value{GDBN} does |
9631 | not yet know how to read. @code{0x@var{nn}} is the symbol type of the | |
d4f3574e | 9632 | uncomprehended information, in hexadecimal. |
c906108c | 9633 | |
7a292a7a SS |
9634 | @value{GDBN} circumvents the error by ignoring this symbol information. |
9635 | This usually allows you to debug your program, though certain symbols | |
c906108c | 9636 | are not accessible. If you encounter such a problem and feel like |
7a292a7a SS |
9637 | debugging it, you can debug @code{@value{GDBP}} with itself, breakpoint |
9638 | on @code{complain}, then go up to the function @code{read_dbx_symtab} | |
9639 | and examine @code{*bufp} to see the symbol. | |
c906108c SS |
9640 | |
9641 | @item stub type has NULL name | |
c906108c | 9642 | |
7a292a7a | 9643 | @value{GDBN} could not find the full definition for a struct or class. |
c906108c | 9644 | |
7a292a7a | 9645 | @item const/volatile indicator missing (ok if using g++ v1.x), got@dots{} |
b37052ae | 9646 | The symbol information for a C@t{++} member function is missing some |
7a292a7a SS |
9647 | information that recent versions of the compiler should have output for |
9648 | it. | |
c906108c SS |
9649 | |
9650 | @item info mismatch between compiler and debugger | |
9651 | ||
9652 | @value{GDBN} could not parse a type specification output by the compiler. | |
7a292a7a | 9653 | |
c906108c SS |
9654 | @end table |
9655 | ||
6d2ebf8b | 9656 | @node Targets |
c906108c | 9657 | @chapter Specifying a Debugging Target |
7a292a7a | 9658 | |
c906108c SS |
9659 | @cindex debugging target |
9660 | @kindex target | |
9661 | ||
9662 | A @dfn{target} is the execution environment occupied by your program. | |
53a5351d JM |
9663 | |
9664 | Often, @value{GDBN} runs in the same host environment as your program; | |
9665 | in that case, the debugging target is specified as a side effect when | |
9666 | you use the @code{file} or @code{core} commands. When you need more | |
c906108c SS |
9667 | flexibility---for example, running @value{GDBN} on a physically separate |
9668 | host, or controlling a standalone system over a serial port or a | |
53a5351d JM |
9669 | realtime system over a TCP/IP connection---you can use the @code{target} |
9670 | command to specify one of the target types configured for @value{GDBN} | |
9671 | (@pxref{Target Commands, ,Commands for managing targets}). | |
c906108c SS |
9672 | |
9673 | @menu | |
9674 | * Active Targets:: Active targets | |
9675 | * Target Commands:: Commands for managing targets | |
c906108c SS |
9676 | * Byte Order:: Choosing target byte order |
9677 | * Remote:: Remote debugging | |
96baa820 | 9678 | * KOD:: Kernel Object Display |
c906108c SS |
9679 | |
9680 | @end menu | |
9681 | ||
6d2ebf8b | 9682 | @node Active Targets |
c906108c | 9683 | @section Active targets |
7a292a7a | 9684 | |
c906108c SS |
9685 | @cindex stacking targets |
9686 | @cindex active targets | |
9687 | @cindex multiple targets | |
9688 | ||
c906108c | 9689 | There are three classes of targets: processes, core files, and |
7a292a7a SS |
9690 | executable files. @value{GDBN} can work concurrently on up to three |
9691 | active targets, one in each class. This allows you to (for example) | |
9692 | start a process and inspect its activity without abandoning your work on | |
9693 | a core file. | |
c906108c SS |
9694 | |
9695 | For example, if you execute @samp{gdb a.out}, then the executable file | |
9696 | @code{a.out} is the only active target. If you designate a core file as | |
9697 | well---presumably from a prior run that crashed and coredumped---then | |
9698 | @value{GDBN} has two active targets and uses them in tandem, looking | |
9699 | first in the corefile target, then in the executable file, to satisfy | |
9700 | requests for memory addresses. (Typically, these two classes of target | |
9701 | are complementary, since core files contain only a program's | |
9702 | read-write memory---variables and so on---plus machine status, while | |
9703 | executable files contain only the program text and initialized data.) | |
c906108c SS |
9704 | |
9705 | When you type @code{run}, your executable file becomes an active process | |
7a292a7a SS |
9706 | target as well. When a process target is active, all @value{GDBN} |
9707 | commands requesting memory addresses refer to that target; addresses in | |
9708 | an active core file or executable file target are obscured while the | |
9709 | process target is active. | |
c906108c | 9710 | |
7a292a7a SS |
9711 | Use the @code{core-file} and @code{exec-file} commands to select a new |
9712 | core file or executable target (@pxref{Files, ,Commands to specify | |
c906108c | 9713 | files}). To specify as a target a process that is already running, use |
7a292a7a SS |
9714 | the @code{attach} command (@pxref{Attach, ,Debugging an already-running |
9715 | process}). | |
c906108c | 9716 | |
6d2ebf8b | 9717 | @node Target Commands |
c906108c SS |
9718 | @section Commands for managing targets |
9719 | ||
9720 | @table @code | |
9721 | @item target @var{type} @var{parameters} | |
7a292a7a SS |
9722 | Connects the @value{GDBN} host environment to a target machine or |
9723 | process. A target is typically a protocol for talking to debugging | |
9724 | facilities. You use the argument @var{type} to specify the type or | |
9725 | protocol of the target machine. | |
c906108c SS |
9726 | |
9727 | Further @var{parameters} are interpreted by the target protocol, but | |
9728 | typically include things like device names or host names to connect | |
9729 | with, process numbers, and baud rates. | |
c906108c SS |
9730 | |
9731 | The @code{target} command does not repeat if you press @key{RET} again | |
9732 | after executing the command. | |
9733 | ||
9734 | @kindex help target | |
9735 | @item help target | |
9736 | Displays the names of all targets available. To display targets | |
9737 | currently selected, use either @code{info target} or @code{info files} | |
9738 | (@pxref{Files, ,Commands to specify files}). | |
9739 | ||
9740 | @item help target @var{name} | |
9741 | Describe a particular target, including any parameters necessary to | |
9742 | select it. | |
9743 | ||
9744 | @kindex set gnutarget | |
9745 | @item set gnutarget @var{args} | |
5d161b24 | 9746 | @value{GDBN} uses its own library BFD to read your files. @value{GDBN} |
c906108c | 9747 | knows whether it is reading an @dfn{executable}, |
5d161b24 DB |
9748 | a @dfn{core}, or a @dfn{.o} file; however, you can specify the file format |
9749 | with the @code{set gnutarget} command. Unlike most @code{target} commands, | |
c906108c SS |
9750 | with @code{gnutarget} the @code{target} refers to a program, not a machine. |
9751 | ||
d4f3574e | 9752 | @quotation |
c906108c SS |
9753 | @emph{Warning:} To specify a file format with @code{set gnutarget}, |
9754 | you must know the actual BFD name. | |
d4f3574e | 9755 | @end quotation |
c906108c | 9756 | |
d4f3574e SS |
9757 | @noindent |
9758 | @xref{Files, , Commands to specify files}. | |
c906108c | 9759 | |
5d161b24 | 9760 | @kindex show gnutarget |
c906108c SS |
9761 | @item show gnutarget |
9762 | Use the @code{show gnutarget} command to display what file format | |
9763 | @code{gnutarget} is set to read. If you have not set @code{gnutarget}, | |
9764 | @value{GDBN} will determine the file format for each file automatically, | |
9765 | and @code{show gnutarget} displays @samp{The current BDF target is "auto"}. | |
9766 | @end table | |
9767 | ||
c906108c SS |
9768 | Here are some common targets (available, or not, depending on the GDB |
9769 | configuration): | |
c906108c SS |
9770 | |
9771 | @table @code | |
9772 | @kindex target exec | |
9773 | @item target exec @var{program} | |
9774 | An executable file. @samp{target exec @var{program}} is the same as | |
9775 | @samp{exec-file @var{program}}. | |
9776 | ||
c906108c SS |
9777 | @kindex target core |
9778 | @item target core @var{filename} | |
9779 | A core dump file. @samp{target core @var{filename}} is the same as | |
9780 | @samp{core-file @var{filename}}. | |
c906108c SS |
9781 | |
9782 | @kindex target remote | |
9783 | @item target remote @var{dev} | |
9784 | Remote serial target in GDB-specific protocol. The argument @var{dev} | |
9785 | specifies what serial device to use for the connection (e.g. | |
9786 | @file{/dev/ttya}). @xref{Remote, ,Remote debugging}. @code{target remote} | |
d4f3574e | 9787 | supports the @code{load} command. This is only useful if you have |
c906108c SS |
9788 | some other way of getting the stub to the target system, and you can put |
9789 | it somewhere in memory where it won't get clobbered by the download. | |
9790 | ||
c906108c SS |
9791 | @kindex target sim |
9792 | @item target sim | |
2df3850c | 9793 | Builtin CPU simulator. @value{GDBN} includes simulators for most architectures. |
104c1213 JM |
9794 | In general, |
9795 | @example | |
9796 | target sim | |
9797 | load | |
9798 | run | |
9799 | @end example | |
d4f3574e | 9800 | @noindent |
104c1213 | 9801 | works; however, you cannot assume that a specific memory map, device |
d4f3574e | 9802 | drivers, or even basic I/O is available, although some simulators do |
104c1213 JM |
9803 | provide these. For info about any processor-specific simulator details, |
9804 | see the appropriate section in @ref{Embedded Processors, ,Embedded | |
9805 | Processors}. | |
9806 | ||
c906108c SS |
9807 | @end table |
9808 | ||
104c1213 | 9809 | Some configurations may include these targets as well: |
c906108c SS |
9810 | |
9811 | @table @code | |
9812 | ||
c906108c SS |
9813 | @kindex target nrom |
9814 | @item target nrom @var{dev} | |
9815 | NetROM ROM emulator. This target only supports downloading. | |
9816 | ||
c906108c SS |
9817 | @end table |
9818 | ||
5d161b24 | 9819 | Different targets are available on different configurations of @value{GDBN}; |
c906108c | 9820 | your configuration may have more or fewer targets. |
c906108c SS |
9821 | |
9822 | Many remote targets require you to download the executable's code | |
9823 | once you've successfully established a connection. | |
9824 | ||
9825 | @table @code | |
9826 | ||
9827 | @kindex load @var{filename} | |
9828 | @item load @var{filename} | |
c906108c SS |
9829 | Depending on what remote debugging facilities are configured into |
9830 | @value{GDBN}, the @code{load} command may be available. Where it exists, it | |
9831 | is meant to make @var{filename} (an executable) available for debugging | |
9832 | on the remote system---by downloading, or dynamic linking, for example. | |
9833 | @code{load} also records the @var{filename} symbol table in @value{GDBN}, like | |
9834 | the @code{add-symbol-file} command. | |
9835 | ||
9836 | If your @value{GDBN} does not have a @code{load} command, attempting to | |
9837 | execute it gets the error message ``@code{You can't do that when your | |
9838 | target is @dots{}}'' | |
c906108c SS |
9839 | |
9840 | The file is loaded at whatever address is specified in the executable. | |
9841 | For some object file formats, you can specify the load address when you | |
9842 | link the program; for other formats, like a.out, the object file format | |
9843 | specifies a fixed address. | |
9844 | @c FIXME! This would be a good place for an xref to the GNU linker doc. | |
9845 | ||
c906108c SS |
9846 | @code{load} does not repeat if you press @key{RET} again after using it. |
9847 | @end table | |
9848 | ||
6d2ebf8b | 9849 | @node Byte Order |
c906108c | 9850 | @section Choosing target byte order |
7a292a7a | 9851 | |
c906108c SS |
9852 | @cindex choosing target byte order |
9853 | @cindex target byte order | |
c906108c SS |
9854 | |
9855 | Some types of processors, such as the MIPS, PowerPC, and Hitachi SH, | |
9856 | offer the ability to run either big-endian or little-endian byte | |
9857 | orders. Usually the executable or symbol will include a bit to | |
9858 | designate the endian-ness, and you will not need to worry about | |
9859 | which to use. However, you may still find it useful to adjust | |
d4f3574e | 9860 | @value{GDBN}'s idea of processor endian-ness manually. |
c906108c SS |
9861 | |
9862 | @table @code | |
9863 | @kindex set endian big | |
9864 | @item set endian big | |
9865 | Instruct @value{GDBN} to assume the target is big-endian. | |
9866 | ||
9867 | @kindex set endian little | |
9868 | @item set endian little | |
9869 | Instruct @value{GDBN} to assume the target is little-endian. | |
9870 | ||
9871 | @kindex set endian auto | |
9872 | @item set endian auto | |
9873 | Instruct @value{GDBN} to use the byte order associated with the | |
9874 | executable. | |
9875 | ||
9876 | @item show endian | |
9877 | Display @value{GDBN}'s current idea of the target byte order. | |
9878 | ||
9879 | @end table | |
9880 | ||
9881 | Note that these commands merely adjust interpretation of symbolic | |
9882 | data on the host, and that they have absolutely no effect on the | |
9883 | target system. | |
9884 | ||
6d2ebf8b | 9885 | @node Remote |
c906108c SS |
9886 | @section Remote debugging |
9887 | @cindex remote debugging | |
9888 | ||
9889 | If you are trying to debug a program running on a machine that cannot run | |
5d161b24 DB |
9890 | @value{GDBN} in the usual way, it is often useful to use remote debugging. |
9891 | For example, you might use remote debugging on an operating system kernel, | |
c906108c SS |
9892 | or on a small system which does not have a general purpose operating system |
9893 | powerful enough to run a full-featured debugger. | |
9894 | ||
9895 | Some configurations of @value{GDBN} have special serial or TCP/IP interfaces | |
9896 | to make this work with particular debugging targets. In addition, | |
5d161b24 | 9897 | @value{GDBN} comes with a generic serial protocol (specific to @value{GDBN}, |
c906108c SS |
9898 | but not specific to any particular target system) which you can use if you |
9899 | write the remote stubs---the code that runs on the remote system to | |
9900 | communicate with @value{GDBN}. | |
9901 | ||
9902 | Other remote targets may be available in your | |
9903 | configuration of @value{GDBN}; use @code{help target} to list them. | |
c906108c | 9904 | |
c906108c | 9905 | @menu |
c906108c | 9906 | * Remote Serial:: @value{GDBN} remote serial protocol |
c906108c SS |
9907 | @end menu |
9908 | ||
6d2ebf8b | 9909 | @node Remote Serial |
104c1213 | 9910 | @subsection The @value{GDBN} remote serial protocol |
7a292a7a | 9911 | |
104c1213 JM |
9912 | @cindex remote serial debugging, overview |
9913 | To debug a program running on another machine (the debugging | |
9914 | @dfn{target} machine), you must first arrange for all the usual | |
9915 | prerequisites for the program to run by itself. For example, for a C | |
9916 | program, you need: | |
c906108c | 9917 | |
104c1213 JM |
9918 | @enumerate |
9919 | @item | |
9920 | A startup routine to set up the C runtime environment; these usually | |
9921 | have a name like @file{crt0}. The startup routine may be supplied by | |
9922 | your hardware supplier, or you may have to write your own. | |
96baa820 | 9923 | |
5d161b24 | 9924 | @item |
d4f3574e | 9925 | A C subroutine library to support your program's |
104c1213 | 9926 | subroutine calls, notably managing input and output. |
96baa820 | 9927 | |
104c1213 JM |
9928 | @item |
9929 | A way of getting your program to the other machine---for example, a | |
9930 | download program. These are often supplied by the hardware | |
9931 | manufacturer, but you may have to write your own from hardware | |
9932 | documentation. | |
9933 | @end enumerate | |
96baa820 | 9934 | |
104c1213 JM |
9935 | The next step is to arrange for your program to use a serial port to |
9936 | communicate with the machine where @value{GDBN} is running (the @dfn{host} | |
9937 | machine). In general terms, the scheme looks like this: | |
96baa820 | 9938 | |
104c1213 JM |
9939 | @table @emph |
9940 | @item On the host, | |
9941 | @value{GDBN} already understands how to use this protocol; when everything | |
9942 | else is set up, you can simply use the @samp{target remote} command | |
9943 | (@pxref{Targets,,Specifying a Debugging Target}). | |
9944 | ||
9945 | @item On the target, | |
9946 | you must link with your program a few special-purpose subroutines that | |
9947 | implement the @value{GDBN} remote serial protocol. The file containing these | |
9948 | subroutines is called a @dfn{debugging stub}. | |
9949 | ||
9950 | On certain remote targets, you can use an auxiliary program | |
9951 | @code{gdbserver} instead of linking a stub into your program. | |
9952 | @xref{Server,,Using the @code{gdbserver} program}, for details. | |
9953 | @end table | |
96baa820 | 9954 | |
104c1213 JM |
9955 | The debugging stub is specific to the architecture of the remote |
9956 | machine; for example, use @file{sparc-stub.c} to debug programs on | |
9957 | @sc{sparc} boards. | |
96baa820 | 9958 | |
104c1213 JM |
9959 | @cindex remote serial stub list |
9960 | These working remote stubs are distributed with @value{GDBN}: | |
96baa820 | 9961 | |
104c1213 JM |
9962 | @table @code |
9963 | ||
9964 | @item i386-stub.c | |
41afff9a | 9965 | @cindex @file{i386-stub.c} |
104c1213 JM |
9966 | @cindex Intel |
9967 | @cindex i386 | |
9968 | For Intel 386 and compatible architectures. | |
9969 | ||
9970 | @item m68k-stub.c | |
41afff9a | 9971 | @cindex @file{m68k-stub.c} |
104c1213 JM |
9972 | @cindex Motorola 680x0 |
9973 | @cindex m680x0 | |
9974 | For Motorola 680x0 architectures. | |
9975 | ||
9976 | @item sh-stub.c | |
41afff9a | 9977 | @cindex @file{sh-stub.c} |
104c1213 JM |
9978 | @cindex Hitachi |
9979 | @cindex SH | |
9980 | For Hitachi SH architectures. | |
9981 | ||
9982 | @item sparc-stub.c | |
41afff9a | 9983 | @cindex @file{sparc-stub.c} |
104c1213 JM |
9984 | @cindex Sparc |
9985 | For @sc{sparc} architectures. | |
9986 | ||
9987 | @item sparcl-stub.c | |
41afff9a | 9988 | @cindex @file{sparcl-stub.c} |
104c1213 JM |
9989 | @cindex Fujitsu |
9990 | @cindex SparcLite | |
9991 | For Fujitsu @sc{sparclite} architectures. | |
9992 | ||
9993 | @end table | |
9994 | ||
9995 | The @file{README} file in the @value{GDBN} distribution may list other | |
9996 | recently added stubs. | |
9997 | ||
9998 | @menu | |
9999 | * Stub Contents:: What the stub can do for you | |
10000 | * Bootstrapping:: What you must do for the stub | |
10001 | * Debug Session:: Putting it all together | |
10002 | * Protocol:: Definition of the communication protocol | |
10003 | * Server:: Using the `gdbserver' program | |
10004 | * NetWare:: Using the `gdbserve.nlm' program | |
10005 | @end menu | |
10006 | ||
6d2ebf8b | 10007 | @node Stub Contents |
104c1213 JM |
10008 | @subsubsection What the stub can do for you |
10009 | ||
10010 | @cindex remote serial stub | |
10011 | The debugging stub for your architecture supplies these three | |
10012 | subroutines: | |
10013 | ||
10014 | @table @code | |
10015 | @item set_debug_traps | |
10016 | @kindex set_debug_traps | |
10017 | @cindex remote serial stub, initialization | |
10018 | This routine arranges for @code{handle_exception} to run when your | |
10019 | program stops. You must call this subroutine explicitly near the | |
10020 | beginning of your program. | |
10021 | ||
10022 | @item handle_exception | |
10023 | @kindex handle_exception | |
10024 | @cindex remote serial stub, main routine | |
10025 | This is the central workhorse, but your program never calls it | |
10026 | explicitly---the setup code arranges for @code{handle_exception} to | |
10027 | run when a trap is triggered. | |
10028 | ||
10029 | @code{handle_exception} takes control when your program stops during | |
10030 | execution (for example, on a breakpoint), and mediates communications | |
10031 | with @value{GDBN} on the host machine. This is where the communications | |
10032 | protocol is implemented; @code{handle_exception} acts as the @value{GDBN} | |
d4f3574e | 10033 | representative on the target machine. It begins by sending summary |
104c1213 JM |
10034 | information on the state of your program, then continues to execute, |
10035 | retrieving and transmitting any information @value{GDBN} needs, until you | |
10036 | execute a @value{GDBN} command that makes your program resume; at that point, | |
10037 | @code{handle_exception} returns control to your own code on the target | |
5d161b24 | 10038 | machine. |
104c1213 JM |
10039 | |
10040 | @item breakpoint | |
10041 | @cindex @code{breakpoint} subroutine, remote | |
10042 | Use this auxiliary subroutine to make your program contain a | |
10043 | breakpoint. Depending on the particular situation, this may be the only | |
10044 | way for @value{GDBN} to get control. For instance, if your target | |
10045 | machine has some sort of interrupt button, you won't need to call this; | |
10046 | pressing the interrupt button transfers control to | |
10047 | @code{handle_exception}---in effect, to @value{GDBN}. On some machines, | |
10048 | simply receiving characters on the serial port may also trigger a trap; | |
10049 | again, in that situation, you don't need to call @code{breakpoint} from | |
10050 | your own program---simply running @samp{target remote} from the host | |
5d161b24 | 10051 | @value{GDBN} session gets control. |
104c1213 JM |
10052 | |
10053 | Call @code{breakpoint} if none of these is true, or if you simply want | |
10054 | to make certain your program stops at a predetermined point for the | |
10055 | start of your debugging session. | |
10056 | @end table | |
10057 | ||
6d2ebf8b | 10058 | @node Bootstrapping |
104c1213 JM |
10059 | @subsubsection What you must do for the stub |
10060 | ||
10061 | @cindex remote stub, support routines | |
10062 | The debugging stubs that come with @value{GDBN} are set up for a particular | |
10063 | chip architecture, but they have no information about the rest of your | |
10064 | debugging target machine. | |
10065 | ||
10066 | First of all you need to tell the stub how to communicate with the | |
10067 | serial port. | |
10068 | ||
10069 | @table @code | |
10070 | @item int getDebugChar() | |
10071 | @kindex getDebugChar | |
10072 | Write this subroutine to read a single character from the serial port. | |
10073 | It may be identical to @code{getchar} for your target system; a | |
10074 | different name is used to allow you to distinguish the two if you wish. | |
10075 | ||
10076 | @item void putDebugChar(int) | |
10077 | @kindex putDebugChar | |
10078 | Write this subroutine to write a single character to the serial port. | |
5d161b24 | 10079 | It may be identical to @code{putchar} for your target system; a |
104c1213 JM |
10080 | different name is used to allow you to distinguish the two if you wish. |
10081 | @end table | |
10082 | ||
10083 | @cindex control C, and remote debugging | |
10084 | @cindex interrupting remote targets | |
10085 | If you want @value{GDBN} to be able to stop your program while it is | |
10086 | running, you need to use an interrupt-driven serial driver, and arrange | |
10087 | for it to stop when it receives a @code{^C} (@samp{\003}, the control-C | |
10088 | character). That is the character which @value{GDBN} uses to tell the | |
10089 | remote system to stop. | |
10090 | ||
10091 | Getting the debugging target to return the proper status to @value{GDBN} | |
10092 | probably requires changes to the standard stub; one quick and dirty way | |
10093 | is to just execute a breakpoint instruction (the ``dirty'' part is that | |
10094 | @value{GDBN} reports a @code{SIGTRAP} instead of a @code{SIGINT}). | |
10095 | ||
10096 | Other routines you need to supply are: | |
10097 | ||
10098 | @table @code | |
10099 | @item void exceptionHandler (int @var{exception_number}, void *@var{exception_address}) | |
10100 | @kindex exceptionHandler | |
10101 | Write this function to install @var{exception_address} in the exception | |
10102 | handling tables. You need to do this because the stub does not have any | |
10103 | way of knowing what the exception handling tables on your target system | |
10104 | are like (for example, the processor's table might be in @sc{rom}, | |
10105 | containing entries which point to a table in @sc{ram}). | |
10106 | @var{exception_number} is the exception number which should be changed; | |
10107 | its meaning is architecture-dependent (for example, different numbers | |
10108 | might represent divide by zero, misaligned access, etc). When this | |
10109 | exception occurs, control should be transferred directly to | |
10110 | @var{exception_address}, and the processor state (stack, registers, | |
10111 | and so on) should be just as it is when a processor exception occurs. So if | |
10112 | you want to use a jump instruction to reach @var{exception_address}, it | |
10113 | should be a simple jump, not a jump to subroutine. | |
10114 | ||
10115 | For the 386, @var{exception_address} should be installed as an interrupt | |
10116 | gate so that interrupts are masked while the handler runs. The gate | |
10117 | should be at privilege level 0 (the most privileged level). The | |
10118 | @sc{sparc} and 68k stubs are able to mask interrupts themselves without | |
10119 | help from @code{exceptionHandler}. | |
10120 | ||
10121 | @item void flush_i_cache() | |
10122 | @kindex flush_i_cache | |
d4f3574e | 10123 | On @sc{sparc} and @sc{sparclite} only, write this subroutine to flush the |
104c1213 JM |
10124 | instruction cache, if any, on your target machine. If there is no |
10125 | instruction cache, this subroutine may be a no-op. | |
10126 | ||
10127 | On target machines that have instruction caches, @value{GDBN} requires this | |
10128 | function to make certain that the state of your program is stable. | |
10129 | @end table | |
10130 | ||
10131 | @noindent | |
10132 | You must also make sure this library routine is available: | |
10133 | ||
10134 | @table @code | |
10135 | @item void *memset(void *, int, int) | |
10136 | @kindex memset | |
10137 | This is the standard library function @code{memset} that sets an area of | |
10138 | memory to a known value. If you have one of the free versions of | |
10139 | @code{libc.a}, @code{memset} can be found there; otherwise, you must | |
10140 | either obtain it from your hardware manufacturer, or write your own. | |
10141 | @end table | |
10142 | ||
10143 | If you do not use the GNU C compiler, you may need other standard | |
10144 | library subroutines as well; this varies from one stub to another, | |
10145 | but in general the stubs are likely to use any of the common library | |
d4f3574e | 10146 | subroutines which @code{@value{GCC}} generates as inline code. |
104c1213 JM |
10147 | |
10148 | ||
6d2ebf8b | 10149 | @node Debug Session |
104c1213 JM |
10150 | @subsubsection Putting it all together |
10151 | ||
10152 | @cindex remote serial debugging summary | |
10153 | In summary, when your program is ready to debug, you must follow these | |
10154 | steps. | |
10155 | ||
10156 | @enumerate | |
10157 | @item | |
6d2ebf8b | 10158 | Make sure you have defined the supporting low-level routines |
104c1213 JM |
10159 | (@pxref{Bootstrapping,,What you must do for the stub}): |
10160 | @display | |
10161 | @code{getDebugChar}, @code{putDebugChar}, | |
10162 | @code{flush_i_cache}, @code{memset}, @code{exceptionHandler}. | |
10163 | @end display | |
10164 | ||
10165 | @item | |
10166 | Insert these lines near the top of your program: | |
10167 | ||
10168 | @example | |
10169 | set_debug_traps(); | |
10170 | breakpoint(); | |
10171 | @end example | |
10172 | ||
10173 | @item | |
10174 | For the 680x0 stub only, you need to provide a variable called | |
10175 | @code{exceptionHook}. Normally you just use: | |
10176 | ||
10177 | @example | |
10178 | void (*exceptionHook)() = 0; | |
10179 | @end example | |
10180 | ||
d4f3574e | 10181 | @noindent |
104c1213 | 10182 | but if before calling @code{set_debug_traps}, you set it to point to a |
598ca718 | 10183 | function in your program, that function is called when |
104c1213 JM |
10184 | @code{@value{GDBN}} continues after stopping on a trap (for example, bus |
10185 | error). The function indicated by @code{exceptionHook} is called with | |
10186 | one parameter: an @code{int} which is the exception number. | |
10187 | ||
10188 | @item | |
10189 | Compile and link together: your program, the @value{GDBN} debugging stub for | |
10190 | your target architecture, and the supporting subroutines. | |
10191 | ||
10192 | @item | |
10193 | Make sure you have a serial connection between your target machine and | |
10194 | the @value{GDBN} host, and identify the serial port on the host. | |
10195 | ||
10196 | @item | |
10197 | @c The "remote" target now provides a `load' command, so we should | |
10198 | @c document that. FIXME. | |
10199 | Download your program to your target machine (or get it there by | |
10200 | whatever means the manufacturer provides), and start it. | |
10201 | ||
10202 | @item | |
10203 | To start remote debugging, run @value{GDBN} on the host machine, and specify | |
10204 | as an executable file the program that is running in the remote machine. | |
10205 | This tells @value{GDBN} how to find your program's symbols and the contents | |
10206 | of its pure text. | |
10207 | ||
d4f3574e | 10208 | @item |
104c1213 | 10209 | @cindex serial line, @code{target remote} |
d4f3574e | 10210 | Establish communication using the @code{target remote} command. |
104c1213 JM |
10211 | Its argument specifies how to communicate with the target |
10212 | machine---either via a devicename attached to a direct serial line, or a | |
10213 | TCP port (usually to a terminal server which in turn has a serial line | |
10214 | to the target). For example, to use a serial line connected to the | |
10215 | device named @file{/dev/ttyb}: | |
10216 | ||
10217 | @example | |
10218 | target remote /dev/ttyb | |
10219 | @end example | |
10220 | ||
10221 | @cindex TCP port, @code{target remote} | |
10222 | To use a TCP connection, use an argument of the form | |
10223 | @code{@var{host}:port}. For example, to connect to port 2828 on a | |
10224 | terminal server named @code{manyfarms}: | |
10225 | ||
10226 | @example | |
10227 | target remote manyfarms:2828 | |
10228 | @end example | |
a2bea4c3 CV |
10229 | |
10230 | If your remote target is actually running on the same machine as | |
10231 | your debugger session (e.g.@: a simulator of your target running on | |
10232 | the same host), you can omit the hostname. For example, to connect | |
10233 | to port 1234 on your local machine: | |
10234 | ||
10235 | @example | |
10236 | target remote :1234 | |
10237 | @end example | |
10238 | @noindent | |
10239 | ||
10240 | Note that the colon is still required here. | |
104c1213 JM |
10241 | @end enumerate |
10242 | ||
10243 | Now you can use all the usual commands to examine and change data and to | |
10244 | step and continue the remote program. | |
10245 | ||
10246 | To resume the remote program and stop debugging it, use the @code{detach} | |
10247 | command. | |
10248 | ||
10249 | @cindex interrupting remote programs | |
10250 | @cindex remote programs, interrupting | |
10251 | Whenever @value{GDBN} is waiting for the remote program, if you type the | |
10252 | interrupt character (often @key{C-C}), @value{GDBN} attempts to stop the | |
10253 | program. This may or may not succeed, depending in part on the hardware | |
10254 | and the serial drivers the remote system uses. If you type the | |
10255 | interrupt character once again, @value{GDBN} displays this prompt: | |
10256 | ||
10257 | @example | |
10258 | Interrupted while waiting for the program. | |
10259 | Give up (and stop debugging it)? (y or n) | |
10260 | @end example | |
10261 | ||
10262 | If you type @kbd{y}, @value{GDBN} abandons the remote debugging session. | |
10263 | (If you decide you want to try again later, you can use @samp{target | |
10264 | remote} again to connect once more.) If you type @kbd{n}, @value{GDBN} | |
10265 | goes back to waiting. | |
10266 | ||
6d2ebf8b | 10267 | @node Protocol |
104c1213 JM |
10268 | @subsubsection Communication protocol |
10269 | ||
10270 | @cindex debugging stub, example | |
10271 | @cindex remote stub, example | |
10272 | @cindex stub example, remote debugging | |
10273 | The stub files provided with @value{GDBN} implement the target side of the | |
10274 | communication protocol, and the @value{GDBN} side is implemented in the | |
10275 | @value{GDBN} source file @file{remote.c}. Normally, you can simply allow | |
10276 | these subroutines to communicate, and ignore the details. (If you're | |
10277 | implementing your own stub file, you can still ignore the details: start | |
10278 | with one of the existing stub files. @file{sparc-stub.c} is the best | |
10279 | organized, and therefore the easiest to read.) | |
10280 | ||
10281 | However, there may be occasions when you need to know something about | |
10282 | the protocol---for example, if there is only one serial port to your | |
10283 | target machine, you might want your program to do something special if | |
10284 | it recognizes a packet meant for @value{GDBN}. | |
10285 | ||
10286 | In the examples below, @samp{<-} and @samp{->} are used to indicate | |
10287 | transmitted and received data respectfully. | |
10288 | ||
10289 | @cindex protocol, @value{GDBN} remote serial | |
10290 | @cindex serial protocol, @value{GDBN} remote | |
10291 | @cindex remote serial protocol | |
6cf7e474 AC |
10292 | All @value{GDBN} commands and responses (other than acknowledgments) are |
10293 | sent as a @var{packet}. A @var{packet} is introduced with the character | |
10294 | @samp{$}, the actual @var{packet-data}, and the terminating character | |
10295 | @samp{#} followed by a two-digit @var{checksum}: | |
104c1213 JM |
10296 | |
10297 | @example | |
10298 | @code{$}@var{packet-data}@code{#}@var{checksum} | |
10299 | @end example | |
10300 | @noindent | |
104c1213 JM |
10301 | |
10302 | @cindex checksum, for @value{GDBN} remote | |
10303 | @noindent | |
10304 | The two-digit @var{checksum} is computed as the modulo 256 sum of all | |
6cf7e474 AC |
10305 | characters between the leading @samp{$} and the trailing @samp{#} (an |
10306 | eight bit unsigned checksum). | |
10307 | ||
10308 | Implementors should note that prior to @value{GDBN} 5.0 the protocol | |
10309 | specification also included an optional two-digit @var{sequence-id}: | |
10310 | ||
10311 | @example | |
10312 | @code{$}@var{sequence-id}@code{:}@var{packet-data}@code{#}@var{checksum} | |
10313 | @end example | |
104c1213 JM |
10314 | |
10315 | @cindex sequence-id, for @value{GDBN} remote | |
10316 | @noindent | |
6cf7e474 AC |
10317 | That @var{sequence-id} was appended to the acknowledgment. @value{GDBN} |
10318 | has never output @var{sequence-id}s. Stubs that handle packets added | |
10319 | since @value{GDBN} 5.0 must not accept @var{sequence-id}. | |
104c1213 | 10320 | |
6cf7e474 | 10321 | @cindex acknowledgment, for @value{GDBN} remote |
104c1213 JM |
10322 | When either the host or the target machine receives a packet, the first |
10323 | response expected is an acknowledgment: either @samp{+} (to indicate | |
10324 | the package was received correctly) or @samp{-} (to request | |
10325 | retransmission): | |
10326 | ||
10327 | @example | |
10328 | <- @code{$}@var{packet-data}@code{#}@var{checksum} | |
10329 | -> @code{+} | |
10330 | @end example | |
10331 | @noindent | |
104c1213 JM |
10332 | |
10333 | The host (@value{GDBN}) sends @var{command}s, and the target (the | |
10334 | debugging stub incorporated in your program) sends a @var{response}. In | |
10335 | the case of step and continue @var{command}s, the response is only sent | |
10336 | when the operation has completed (the target has again stopped). | |
10337 | ||
10338 | @var{packet-data} consists of a sequence of characters with the | |
6cf7e474 AC |
10339 | exception of @samp{#} and @samp{$} (see @samp{X} packet for additional |
10340 | exceptions). | |
10341 | ||
10342 | Fields within the packet should be separated using @samp{,} @samp{;} or | |
10343 | @samp{:}. Except where otherwise noted all numbers are represented in | |
10344 | HEX with leading zeros suppressed. | |
10345 | ||
10346 | Implementors should note that prior to @value{GDBN} 5.0, the character | |
10347 | @samp{:} could not appear as the third character in a packet (as it | |
10348 | would potentially conflict with the @var{sequence-id}). | |
104c1213 JM |
10349 | |
10350 | Response @var{data} can be run-length encoded to save space. A @samp{*} | |
c3f6f71d | 10351 | means that the next character is an @sc{ascii} encoding giving a repeat count |
104c1213 JM |
10352 | which stands for that many repetitions of the character preceding the |
10353 | @samp{*}. The encoding is @code{n+29}, yielding a printable character | |
d4f3574e SS |
10354 | where @code{n >=3} (which is where rle starts to win). The printable |
10355 | characters @samp{$}, @samp{#}, @samp{+} and @samp{-} or with a numeric | |
10356 | value greater than 126 should not be used. | |
10357 | ||
10358 | Some remote systems have used a different run-length encoding mechanism | |
10359 | loosely refered to as the cisco encoding. Following the @samp{*} | |
10360 | character are two hex digits that indicate the size of the packet. | |
104c1213 JM |
10361 | |
10362 | So: | |
10363 | @example | |
10364 | "@code{0* }" | |
10365 | @end example | |
10366 | @noindent | |
10367 | means the same as "0000". | |
10368 | ||
598ca718 | 10369 | The error response returned for some packets includes a two character |
104c1213 JM |
10370 | error number. That number is not well defined. |
10371 | ||
10372 | For any @var{command} not supported by the stub, an empty response | |
10373 | (@samp{$#00}) should be returned. That way it is possible to extend the | |
10374 | protocol. A newer @value{GDBN} can tell if a packet is supported based | |
d4f3574e | 10375 | on that response. |
104c1213 | 10376 | |
f1251bdd C |
10377 | A stub is required to support the @samp{g}, @samp{G}, @samp{m}, @samp{M}, |
10378 | @samp{c}, and @samp{s} @var{command}s. All other @var{command}s are | |
10379 | optional. | |
10380 | ||
104c1213 JM |
10381 | Below is a complete list of all currently defined @var{command}s and |
10382 | their corresponding response @var{data}: | |
598ca718 | 10383 | @page |
104c1213 JM |
10384 | @multitable @columnfractions .30 .30 .40 |
10385 | @item Packet | |
10386 | @tab Request | |
10387 | @tab Description | |
10388 | ||
df2396a1 | 10389 | @item extended mode |
104c1213 JM |
10390 | @tab @code{!} |
10391 | @tab | |
df2396a1 | 10392 | Enable extended mode. In extended mode, the remote server is made |
656db9b0 | 10393 | persistent. The @samp{R} packet is used to restart the program being |
df2396a1 | 10394 | debugged. |
104c1213 | 10395 | @item |
df2396a1 | 10396 | @tab reply @samp{OK} |
104c1213 | 10397 | @tab |
df2396a1 | 10398 | The remote target both supports and has enabled extended mode. |
104c1213 JM |
10399 | |
10400 | @item last signal | |
10401 | @tab @code{?} | |
10402 | @tab | |
d4f3574e SS |
10403 | Indicate the reason the target halted. The reply is the same as for step |
10404 | and continue. | |
10405 | @item | |
10406 | @tab reply | |
10407 | @tab see below | |
10408 | ||
104c1213 JM |
10409 | |
10410 | @item reserved | |
10411 | @tab @code{a} | |
5d161b24 | 10412 | @tab Reserved for future use |
104c1213 | 10413 | |
f1251bdd | 10414 | @item set program arguments @strong{(reserved)} |
104c1213 JM |
10415 | @tab @code{A}@var{arglen}@code{,}@var{argnum}@code{,}@var{arg}@code{,...} |
10416 | @tab | |
598ca718 EZ |
10417 | @item |
10418 | @tab | |
10419 | @tab | |
104c1213 JM |
10420 | Initialized @samp{argv[]} array passed into program. @var{arglen} |
10421 | specifies the number of bytes in the hex encoded byte stream @var{arg}. | |
d4f3574e | 10422 | See @file{gdbserver} for more details. |
104c1213 JM |
10423 | @item |
10424 | @tab reply @code{OK} | |
10425 | @item | |
10426 | @tab reply @code{E}@var{NN} | |
10427 | ||
10428 | @item set baud @strong{(deprecated)} | |
10429 | @tab @code{b}@var{baud} | |
10430 | @tab | |
10431 | Change the serial line speed to @var{baud}. JTC: @emph{When does the | |
10432 | transport layer state change? When it's received, or after the ACK is | |
10433 | transmitted. In either case, there are problems if the command or the | |
10434 | acknowledgment packet is dropped.} Stan: @emph{If people really wanted | |
10435 | to add something like this, and get it working for the first time, they | |
10436 | ought to modify ser-unix.c to send some kind of out-of-band message to a | |
10437 | specially-setup stub and have the switch happen "in between" packets, so | |
10438 | that from remote protocol's point of view, nothing actually | |
10439 | happened.} | |
10440 | ||
10441 | @item set breakpoint @strong{(deprecated)} | |
10442 | @tab @code{B}@var{addr},@var{mode} | |
10443 | @tab | |
10444 | Set (@var{mode} is @samp{S}) or clear (@var{mode} is @samp{C}) a | |
10445 | breakpoint at @var{addr}. @emph{This has been replaced by the @samp{Z} and | |
10446 | @samp{z} packets.} | |
10447 | ||
10448 | @item continue | |
10449 | @tab @code{c}@var{addr} | |
10450 | @tab | |
10451 | @var{addr} is address to resume. If @var{addr} is omitted, resume at | |
10452 | current address. | |
10453 | @item | |
10454 | @tab reply | |
10455 | @tab see below | |
10456 | ||
f1251bdd | 10457 | @item continue with signal |
104c1213 JM |
10458 | @tab @code{C}@var{sig}@code{;}@var{addr} |
10459 | @tab | |
10460 | Continue with signal @var{sig} (hex signal number). If | |
10461 | @code{;}@var{addr} is omitted, resume at same address. | |
10462 | @item | |
10463 | @tab reply | |
10464 | @tab see below | |
10465 | ||
598ca718 | 10466 | @item toggle debug @strong{(deprecated)} |
104c1213 JM |
10467 | @tab @code{d} |
10468 | @tab | |
d4f3574e | 10469 | toggle debug flag. |
104c1213 | 10470 | |
f1251bdd | 10471 | @item detach |
104c1213 | 10472 | @tab @code{D} |
d4f3574e | 10473 | @tab |
2df3850c JM |
10474 | Detach @value{GDBN} from the remote system. Sent to the remote target before |
10475 | @value{GDBN} disconnects. | |
d4f3574e SS |
10476 | @item |
10477 | @tab reply @emph{no response} | |
10478 | @tab | |
598ca718 | 10479 | @value{GDBN} does not check for any response after sending this packet. |
104c1213 JM |
10480 | |
10481 | @item reserved | |
10482 | @tab @code{e} | |
5d161b24 | 10483 | @tab Reserved for future use |
104c1213 JM |
10484 | |
10485 | @item reserved | |
10486 | @tab @code{E} | |
5d161b24 | 10487 | @tab Reserved for future use |
104c1213 JM |
10488 | |
10489 | @item reserved | |
10490 | @tab @code{f} | |
5d161b24 | 10491 | @tab Reserved for future use |
104c1213 JM |
10492 | |
10493 | @item reserved | |
10494 | @tab @code{F} | |
5d161b24 | 10495 | @tab Reserved for future use |
104c1213 JM |
10496 | |
10497 | @item read registers | |
10498 | @tab @code{g} | |
10499 | @tab Read general registers. | |
10500 | @item | |
10501 | @tab reply @var{XX...} | |
10502 | @tab | |
10503 | Each byte of register data is described by two hex digits. The bytes | |
10504 | with the register are transmitted in target byte order. The size of | |
d4f3574e | 10505 | each register and their position within the @samp{g} @var{packet} are |
2df3850c | 10506 | determined by the @value{GDBN} internal macros @var{REGISTER_RAW_SIZE} and |
d4f3574e SS |
10507 | @var{REGISTER_NAME} macros. The specification of several standard |
10508 | @code{g} packets is specified below. | |
104c1213 JM |
10509 | @item |
10510 | @tab @code{E}@var{NN} | |
10511 | @tab for an error. | |
10512 | ||
10513 | @item write regs | |
10514 | @tab @code{G}@var{XX...} | |
10515 | @tab | |
10516 | See @samp{g} for a description of the @var{XX...} data. | |
10517 | @item | |
10518 | @tab reply @code{OK} | |
10519 | @tab for success | |
10520 | @item | |
10521 | @tab reply @code{E}@var{NN} | |
10522 | @tab for an error | |
10523 | ||
10524 | @item reserved | |
10525 | @tab @code{h} | |
5d161b24 | 10526 | @tab Reserved for future use |
104c1213 | 10527 | |
f1251bdd | 10528 | @item set thread |
104c1213 JM |
10529 | @tab @code{H}@var{c}@var{t...} |
10530 | @tab | |
d4f3574e SS |
10531 | Set thread for subsequent operations (@samp{m}, @samp{M}, @samp{g}, |
10532 | @samp{G}, et.al.). @var{c} = @samp{c} for thread used in step and | |
10533 | continue; @var{t...} can be -1 for all threads. @var{c} = @samp{g} for | |
10534 | thread used in other operations. If zero, pick a thread, any thread. | |
104c1213 JM |
10535 | @item |
10536 | @tab reply @code{OK} | |
10537 | @tab for success | |
10538 | @item | |
10539 | @tab reply @code{E}@var{NN} | |
10540 | @tab for an error | |
10541 | ||
d4f3574e SS |
10542 | @c FIXME: JTC: |
10543 | @c 'H': How restrictive (or permissive) is the thread model. If a | |
5d161b24 | 10544 | @c thread is selected and stopped, are other threads allowed |
d4f3574e SS |
10545 | @c to continue to execute? As I mentioned above, I think the |
10546 | @c semantics of each command when a thread is selected must be | |
10547 | @c described. For example: | |
10548 | @c | |
10549 | @c 'g': If the stub supports threads and a specific thread is | |
10550 | @c selected, returns the register block from that thread; | |
10551 | @c otherwise returns current registers. | |
10552 | @c | |
10553 | @c 'G' If the stub supports threads and a specific thread is | |
10554 | @c selected, sets the registers of the register block of | |
10555 | @c that thread; otherwise sets current registers. | |
10556 | ||
f1251bdd | 10557 | @item cycle step @strong{(draft)} |
104c1213 JM |
10558 | @tab @code{i}@var{addr}@code{,}@var{nnn} |
10559 | @tab | |
10560 | Step the remote target by a single clock cycle. If @code{,}@var{nnn} is | |
10561 | present, cycle step @var{nnn} cycles. If @var{addr} is present, cycle | |
10562 | step starting at that address. | |
10563 | ||
f1251bdd | 10564 | @item signal then cycle step @strong{(reserved)} |
104c1213 JM |
10565 | @tab @code{I} |
10566 | @tab | |
10567 | See @samp{i} and @samp{S} for likely syntax and semantics. | |
10568 | ||
10569 | @item reserved | |
10570 | @tab @code{j} | |
10571 | @tab Reserved for future use | |
10572 | ||
10573 | @item reserved | |
10574 | @tab @code{J} | |
5d161b24 | 10575 | @tab Reserved for future use |
104c1213 | 10576 | |
f1251bdd | 10577 | @item kill request |
104c1213 JM |
10578 | @tab @code{k} |
10579 | @tab | |
d4f3574e SS |
10580 | FIXME: @emph{There is no description of how operate when a specific |
10581 | thread context has been selected (ie. does 'k' kill only that thread?)}. | |
104c1213 JM |
10582 | |
10583 | @item reserved | |
10584 | @tab @code{l} | |
5d161b24 | 10585 | @tab Reserved for future use |
104c1213 JM |
10586 | |
10587 | @item reserved | |
10588 | @tab @code{L} | |
5d161b24 | 10589 | @tab Reserved for future use |
104c1213 JM |
10590 | |
10591 | @item read memory | |
10592 | @tab @code{m}@var{addr}@code{,}@var{length} | |
10593 | @tab | |
10594 | Read @var{length} bytes of memory starting at address @var{addr}. | |
2df3850c | 10595 | Neither @value{GDBN} nor the stub assume that sized memory transfers are assumed |
d4f3574e SS |
10596 | using word alligned accesses. FIXME: @emph{A word aligned memory |
10597 | transfer mechanism is needed.} | |
104c1213 JM |
10598 | @item |
10599 | @tab reply @var{XX...} | |
10600 | @tab | |
d4f3574e | 10601 | @var{XX...} is mem contents. Can be fewer bytes than requested if able |
2df3850c | 10602 | to read only part of the data. Neither @value{GDBN} nor the stub assume that |
d4f3574e SS |
10603 | sized memory transfers are assumed using word alligned accesses. FIXME: |
10604 | @emph{A word aligned memory transfer mechanism is needed.} | |
104c1213 JM |
10605 | @item |
10606 | @tab reply @code{E}@var{NN} | |
10607 | @tab @var{NN} is errno | |
10608 | ||
10609 | @item write mem | |
10610 | @tab @code{M}@var{addr},@var{length}@code{:}@var{XX...} | |
10611 | @tab | |
10612 | Write @var{length} bytes of memory starting at address @var{addr}. | |
10613 | @var{XX...} is the data. | |
10614 | @item | |
10615 | @tab reply @code{OK} | |
10616 | @tab for success | |
10617 | @item | |
10618 | @tab reply @code{E}@var{NN} | |
10619 | @tab | |
10620 | for an error (this includes the case where only part of the data was | |
10621 | written). | |
10622 | ||
10623 | @item reserved | |
10624 | @tab @code{n} | |
5d161b24 | 10625 | @tab Reserved for future use |
104c1213 JM |
10626 | |
10627 | @item reserved | |
10628 | @tab @code{N} | |
5d161b24 | 10629 | @tab Reserved for future use |
104c1213 JM |
10630 | |
10631 | @item reserved | |
10632 | @tab @code{o} | |
5d161b24 | 10633 | @tab Reserved for future use |
104c1213 JM |
10634 | |
10635 | @item reserved | |
10636 | @tab @code{O} | |
5d161b24 | 10637 | @tab Reserved for future use |
104c1213 JM |
10638 | |
10639 | @item read reg @strong{(reserved)} | |
10640 | @tab @code{p}@var{n...} | |
10641 | @tab | |
10642 | See write register. | |
10643 | @item | |
10644 | @tab return @var{r....} | |
10645 | @tab The hex encoded value of the register in target byte order. | |
10646 | ||
f1251bdd | 10647 | @item write reg |
104c1213 JM |
10648 | @tab @code{P}@var{n...}@code{=}@var{r...} |
10649 | @tab | |
10650 | Write register @var{n...} with value @var{r...}, which contains two hex | |
10651 | digits for each byte in the register (target byte order). | |
10652 | @item | |
10653 | @tab reply @code{OK} | |
10654 | @tab for success | |
10655 | @item | |
10656 | @tab reply @code{E}@var{NN} | |
10657 | @tab for an error | |
10658 | ||
f1251bdd | 10659 | @item general query |
104c1213 JM |
10660 | @tab @code{q}@var{query} |
10661 | @tab | |
598ca718 | 10662 | Request info about @var{query}. In general @value{GDBN} queries |
104c1213 | 10663 | have a leading upper case letter. Custom vendor queries should use a |
d4f3574e SS |
10664 | company prefix (in lower case) ex: @samp{qfsf.var}. @var{query} may |
10665 | optionally be followed by a @samp{,} or @samp{;} separated list. Stubs | |
10666 | must ensure that they match the full @var{query} name. | |
104c1213 JM |
10667 | @item |
10668 | @tab reply @code{XX...} | |
d4f3574e | 10669 | @tab Hex encoded data from query. The reply can not be empty. |
104c1213 JM |
10670 | @item |
10671 | @tab reply @code{E}@var{NN} | |
10672 | @tab error reply | |
10673 | @item | |
10674 | @tab reply @samp{} | |
10675 | @tab Indicating an unrecognized @var{query}. | |
10676 | ||
f1251bdd | 10677 | @item general set |
104c1213 JM |
10678 | @tab @code{Q}@var{var}@code{=}@var{val} |
10679 | @tab | |
10680 | Set value of @var{var} to @var{val}. See @samp{q} for a discussing of | |
10681 | naming conventions. | |
10682 | ||
598ca718 | 10683 | @item reset @strong{(deprecated)} |
d4f3574e SS |
10684 | @tab @code{r} |
10685 | @tab | |
10686 | Reset the entire system. | |
104c1213 | 10687 | |
f1251bdd | 10688 | @item remote restart |
104c1213 JM |
10689 | @tab @code{R}@var{XX} |
10690 | @tab | |
df2396a1 AC |
10691 | Restart the program being debugged. @var{XX}, while needed, is ignored. |
10692 | This packet is only available in extended mode. | |
10693 | @item | |
10694 | @tab | |
10695 | no reply | |
10696 | @tab | |
10697 | The @samp{R} packet has no reply. | |
104c1213 | 10698 | |
f1251bdd | 10699 | @item step |
104c1213 JM |
10700 | @tab @code{s}@var{addr} |
10701 | @tab | |
10702 | @var{addr} is address to resume. If @var{addr} is omitted, resume at | |
10703 | same address. | |
10704 | @item | |
10705 | @tab reply | |
10706 | @tab see below | |
10707 | ||
f1251bdd | 10708 | @item step with signal |
104c1213 JM |
10709 | @tab @code{S}@var{sig}@code{;}@var{addr} |
10710 | @tab | |
10711 | Like @samp{C} but step not continue. | |
10712 | @item | |
10713 | @tab reply | |
10714 | @tab see below | |
10715 | ||
f1251bdd | 10716 | @item search |
104c1213 JM |
10717 | @tab @code{t}@var{addr}@code{:}@var{PP}@code{,}@var{MM} |
10718 | @tab | |
10719 | Search backwards starting at address @var{addr} for a match with pattern | |
10720 | @var{PP} and mask @var{MM}. @var{PP} and @var{MM} are 4 | |
d4f3574e | 10721 | bytes. @var{addr} must be at least 3 digits. |
104c1213 | 10722 | |
f1251bdd | 10723 | @item thread alive |
104c1213 JM |
10724 | @tab @code{T}@var{XX} |
10725 | @tab Find out if the thread XX is alive. | |
10726 | @item | |
10727 | @tab reply @code{OK} | |
10728 | @tab thread is still alive | |
10729 | @item | |
10730 | @tab reply @code{E}@var{NN} | |
10731 | @tab thread is dead | |
5d161b24 | 10732 | |
104c1213 JM |
10733 | @item reserved |
10734 | @tab @code{u} | |
5d161b24 | 10735 | @tab Reserved for future use |
104c1213 JM |
10736 | |
10737 | @item reserved | |
10738 | @tab @code{U} | |
5d161b24 | 10739 | @tab Reserved for future use |
104c1213 JM |
10740 | |
10741 | @item reserved | |
10742 | @tab @code{v} | |
5d161b24 | 10743 | @tab Reserved for future use |
104c1213 JM |
10744 | |
10745 | @item reserved | |
10746 | @tab @code{V} | |
5d161b24 | 10747 | @tab Reserved for future use |
104c1213 JM |
10748 | |
10749 | @item reserved | |
10750 | @tab @code{w} | |
5d161b24 | 10751 | @tab Reserved for future use |
104c1213 JM |
10752 | |
10753 | @item reserved | |
10754 | @tab @code{W} | |
5d161b24 | 10755 | @tab Reserved for future use |
104c1213 JM |
10756 | |
10757 | @item reserved | |
10758 | @tab @code{x} | |
5d161b24 | 10759 | @tab Reserved for future use |
104c1213 | 10760 | |
f1251bdd | 10761 | @item write mem (binary) |
104c1213 JM |
10762 | @tab @code{X}@var{addr}@code{,}@var{length}@var{:}@var{XX...} |
10763 | @tab | |
10764 | @var{addr} is address, @var{length} is number of bytes, @var{XX...} is | |
d4f3574e SS |
10765 | binary data. The characters @code{$}, @code{#}, and @code{0x7d} are |
10766 | escaped using @code{0x7d}. | |
104c1213 JM |
10767 | @item |
10768 | @tab reply @code{OK} | |
10769 | @tab for success | |
10770 | @item | |
10771 | @tab reply @code{E}@var{NN} | |
10772 | @tab for an error | |
10773 | ||
10774 | @item reserved | |
10775 | @tab @code{y} | |
5d161b24 | 10776 | @tab Reserved for future use |
104c1213 JM |
10777 | |
10778 | @item reserved | |
10779 | @tab @code{Y} | |
5d161b24 | 10780 | @tab Reserved for future use |
104c1213 | 10781 | |
f1251bdd | 10782 | @item remove break or watchpoint @strong{(draft)} |
104c1213 JM |
10783 | @tab @code{z}@var{t}@code{,}@var{addr}@code{,}@var{length} |
10784 | @tab | |
10785 | See @samp{Z}. | |
10786 | ||
f1251bdd | 10787 | @item insert break or watchpoint @strong{(draft)} |
104c1213 JM |
10788 | @tab @code{Z}@var{t}@code{,}@var{addr}@code{,}@var{length} |
10789 | @tab | |
10790 | @var{t} is type: @samp{0} - software breakpoint, @samp{1} - hardware | |
10791 | breakpoint, @samp{2} - write watchpoint, @samp{3} - read watchpoint, | |
10792 | @samp{4} - access watchpoint; @var{addr} is address; @var{length} is in | |
10793 | bytes. For a software breakpoint, @var{length} specifies the size of | |
10794 | the instruction to be patched. For hardware breakpoints and watchpoints | |
d4f3574e SS |
10795 | @var{length} specifies the memory region to be monitored. To avoid |
10796 | potential problems with duplicate packets, the operations should be | |
6d2ebf8b | 10797 | implemented in an idempotent way. |
104c1213 JM |
10798 | @item |
10799 | @tab reply @code{E}@var{NN} | |
10800 | @tab for an error | |
10801 | @item | |
10802 | @tab reply @code{OK} | |
10803 | @tab for success | |
10804 | @item | |
10805 | @tab @samp{} | |
10806 | @tab If not supported. | |
10807 | ||
10808 | @item reserved | |
10809 | @tab <other> | |
5d161b24 | 10810 | @tab Reserved for future use |
104c1213 JM |
10811 | |
10812 | @end multitable | |
10813 | ||
d4f3574e SS |
10814 | The @samp{C}, @samp{c}, @samp{S}, @samp{s} and @samp{?} packets can |
10815 | receive any of the below as a reply. In the case of the @samp{C}, | |
10816 | @samp{c}, @samp{S} and @samp{s} packets, that reply is only returned | |
10817 | when the target halts. In the below the exact meaning of @samp{signal | |
10818 | number} is poorly defined. In general one of the UNIX signal numbering | |
10819 | conventions is used. | |
104c1213 JM |
10820 | |
10821 | @multitable @columnfractions .4 .6 | |
10822 | ||
10823 | @item @code{S}@var{AA} | |
10824 | @tab @var{AA} is the signal number | |
10825 | ||
10826 | @item @code{T}@var{AA}@var{n...}@code{:}@var{r...}@code{;}@var{n...}@code{:}@var{r...}@code{;}@var{n...}@code{:}@var{r...}@code{;} | |
10827 | @tab | |
10828 | @var{AA} = two hex digit signal number; @var{n...} = register number | |
10829 | (hex), @var{r...} = target byte ordered register contents, size defined | |
10830 | by @code{REGISTER_RAW_SIZE}; @var{n...} = @samp{thread}, @var{r...} = | |
10831 | thread process ID, this is a hex integer; @var{n...} = other string not | |
d4f3574e | 10832 | starting with valid hex digit. @value{GDBN} should ignore this |
104c1213 JM |
10833 | @var{n...}, @var{r...} pair and go on to the next. This way we can |
10834 | extend the protocol. | |
10835 | ||
10836 | @item @code{W}@var{AA} | |
10837 | @tab | |
10838 | The process exited, and @var{AA} is the exit status. This is only | |
10839 | applicable for certains sorts of targets. | |
10840 | ||
10841 | @item @code{X}@var{AA} | |
10842 | @tab | |
10843 | The process terminated with signal @var{AA}. | |
10844 | ||
6d2ebf8b | 10845 | @item @code{N}@var{AA}@code{;}@var{t...}@code{;}@var{d...}@code{;}@var{b...} @strong{(obsolete)} |
104c1213 | 10846 | @tab |
6d2ebf8b SS |
10847 | @var{AA} = signal number; @var{t...} = address of symbol "_start"; |
10848 | @var{d...} = base of data section; @var{b...} = base of bss section. | |
10849 | @emph{Note: only used by Cisco Systems targets. The difference between | |
10850 | this reply and the "qOffsets" query is that the 'N' packet may arrive | |
10851 | spontaneously whereas the 'qOffsets' is a query initiated by the host | |
10852 | debugger.} | |
104c1213 JM |
10853 | |
10854 | @item @code{O}@var{XX...} | |
10855 | @tab | |
c3f6f71d | 10856 | @var{XX...} is hex encoding of @sc{ascii} data. This can happen at any time |
104c1213 JM |
10857 | while the program is running and the debugger should continue to wait |
10858 | for 'W', 'T', etc. | |
10859 | ||
10860 | @end multitable | |
10861 | ||
d4f3574e SS |
10862 | The following set and query packets have already been defined. |
10863 | ||
10864 | @multitable @columnfractions .2 .2 .6 | |
10865 | ||
10866 | @item current thread | |
10867 | @tab @code{q}@code{C} | |
10868 | @tab Return the current thread id. | |
10869 | @item | |
10870 | @tab reply @code{QC}@var{pid} | |
10871 | @tab | |
10872 | Where @var{pid} is a HEX encoded 16 bit process id. | |
10873 | @item | |
10874 | @tab reply * | |
10875 | @tab Any other reply implies the old pid. | |
10876 | ||
bba2971c MS |
10877 | @item all thread ids |
10878 | @tab @code{q}@code{fThreadInfo} | |
10879 | @item | |
10880 | @tab @code{q}@code{sThreadInfo} | |
d4f3574e | 10881 | @tab |
bba2971c MS |
10882 | Obtain a list of active thread ids from the target (OS). Since there |
10883 | may be too many active threads to fit into one reply packet, this query | |
10884 | works iteratively: it may require more than one query/reply sequence to | |
10885 | obtain the entire list of threads. The first query of the sequence will | |
5d161b24 | 10886 | be the @code{qf}@code{ThreadInfo} query; subsequent queries in the |
bba2971c | 10887 | sequence will be the @code{qs}@code{ThreadInfo} query. |
d4f3574e | 10888 | @item |
bba2971c MS |
10889 | @tab |
10890 | @tab NOTE: replaces the @code{qL} query (see below). | |
d4f3574e | 10891 | @item |
5d161b24 | 10892 | @tab reply @code{m}@var{<id>} |
bba2971c MS |
10893 | @tab A single thread id |
10894 | @item | |
00e4a2e4 | 10895 | @tab reply @code{m}@var{<id>},@var{<id>...} |
bba2971c MS |
10896 | @tab a comma-separated list of thread ids |
10897 | @item | |
10898 | @tab reply @code{l} | |
10899 | @tab (lower case 'el') denotes end of list. | |
10900 | @item | |
10901 | @tab | |
10902 | @tab | |
10903 | In response to each query, the target will reply with a list of one | |
10904 | or more thread ids, in big-endian hex, separated by commas. GDB will | |
10905 | respond to each reply with a request for more thread ids (using the | |
10906 | @code{qs} form of the query), until the target responds with @code{l} | |
10907 | (lower-case el, for @code{'last'}). | |
10908 | ||
10909 | @item extra thread info | |
480ff1fb | 10910 | @tab @code{q}@code{ThreadExtraInfo}@code{,}@var{id} |
bba2971c MS |
10911 | @tab |
10912 | @item | |
10913 | @tab | |
10914 | @tab | |
10915 | Where @var{<id>} is a thread-id in big-endian hex. | |
10916 | Obtain a printable string description of a thread's attributes from | |
10917 | the target OS. This string may contain anything that the target OS | |
10918 | thinks is interesting for @value{GDBN} to tell the user about the thread. | |
10919 | The string is displayed in @value{GDBN}'s @samp{info threads} display. | |
5d161b24 | 10920 | Some examples of possible thread extra info strings are "Runnable", or |
bba2971c MS |
10921 | "Blocked on Mutex". |
10922 | @item | |
10923 | @tab reply @var{XX...} | |
10924 | @tab | |
10925 | Where @var{XX...} is a hex encoding of @sc{ascii} data, comprising the | |
10926 | printable string containing the extra information about the thread's | |
10927 | attributes. | |
d4f3574e SS |
10928 | |
10929 | @item query @var{LIST} or @var{threadLIST} @strong{(deprecated)} | |
10930 | @tab @code{q}@code{L}@var{startflag}@var{threadcount}@var{nextthread} | |
10931 | @tab | |
2b628194 MS |
10932 | @item |
10933 | @tab | |
10934 | @tab | |
d4f3574e SS |
10935 | Obtain thread information from RTOS. Where: @var{startflag} (one hex |
10936 | digit) is one to indicate the first query and zero to indicate a | |
10937 | subsequent query; @var{threadcount} (two hex digits) is the maximum | |
10938 | number of threads the response packet can contain; and @var{nextthread} | |
10939 | (eight hex digits), for subsequent queries (@var{startflag} is zero), is | |
10940 | returned in the response as @var{argthread}. | |
10941 | @item | |
bba2971c MS |
10942 | @tab |
10943 | @tab NOTE: this query is replaced by the @code{q}@code{fThreadInfo} | |
10944 | query (see above). | |
10945 | @item | |
d4f3574e SS |
10946 | @tab reply @code{q}@code{M}@var{count}@var{done}@var{argthread}@var{thread...} |
10947 | @tab | |
2b628194 MS |
10948 | @item |
10949 | @tab | |
10950 | @tab | |
d4f3574e SS |
10951 | Where: @var{count} (two hex digits) is the number of threads being |
10952 | returned; @var{done} (one hex digit) is zero to indicate more threads | |
10953 | and one indicates no further threads; @var{argthreadid} (eight hex | |
10954 | digits) is @var{nextthread} from the request packet; @var{thread...} is | |
10955 | a sequence of thread IDs from the target. @var{threadid} (eight hex | |
10956 | digits). See @code{remote.c:parse_threadlist_response()}. | |
10957 | ||
bba2971c MS |
10958 | @item compute CRC of memory block |
10959 | @tab @code{q}@code{CRC:}@var{addr}@code{,}@var{length} | |
10960 | @tab | |
10961 | @item | |
10962 | @tab reply @code{E}@var{NN} | |
10963 | @tab An error (such as memory fault) | |
10964 | @item | |
10965 | @tab reply @code{C}@var{CRC32} | |
10966 | @tab A 32 bit cyclic redundancy check of the specified memory region. | |
10967 | ||
d4f3574e SS |
10968 | @item query sect offs |
10969 | @tab @code{q}@code{Offsets} | |
917317f4 JM |
10970 | @tab |
10971 | Get section offsets that the target used when re-locating the downloaded | |
10972 | image. @emph{Note: while a @code{Bss} offset is included in the | |
10973 | response, @value{GDBN} ignores this and instead applies the @code{Data} | |
10974 | offset to the @code{Bss} section.} | |
d4f3574e SS |
10975 | @item |
10976 | @tab reply @code{Text=}@var{xxx}@code{;Data=}@var{yyy}@code{;Bss=}@var{zzz} | |
10977 | ||
10978 | @item thread info request | |
10979 | @tab @code{q}@code{P}@var{mode}@var{threadid} | |
10980 | @tab | |
598ca718 EZ |
10981 | @item |
10982 | @tab | |
10983 | @tab | |
d4f3574e SS |
10984 | Returns information on @var{threadid}. Where: @var{mode} is a hex |
10985 | encoded 32 bit mode; @var{threadid} is a hex encoded 64 bit thread ID. | |
10986 | @item | |
10987 | @tab reply * | |
10988 | @tab | |
10989 | See @code{remote.c:remote_unpack_thread_info_response()}. | |
10990 | ||
10991 | @item remote command | |
10992 | @tab @code{q}@code{Rcmd,}@var{COMMAND} | |
10993 | @tab | |
598ca718 EZ |
10994 | @item |
10995 | @tab | |
10996 | @tab | |
d4f3574e SS |
10997 | @var{COMMAND} (hex encoded) is passed to the local interpreter for |
10998 | execution. Invalid commands should be reported using the output string. | |
10999 | Before the final result packet, the target may also respond with a | |
11000 | number of intermediate @code{O}@var{OUTPUT} console output | |
11001 | packets. @emph{Implementors should note that providing access to a | |
11002 | stubs's interpreter may have security implications}. | |
11003 | @item | |
11004 | @tab reply @code{OK} | |
11005 | @tab | |
11006 | A command response with no output. | |
11007 | @item | |
11008 | @tab reply @var{OUTPUT} | |
11009 | @tab | |
11010 | A command response with the hex encoded output string @var{OUTPUT}. | |
11011 | @item | |
11012 | @tab reply @code{E}@var{NN} | |
11013 | @tab | |
11014 | Indicate a badly formed request. | |
11015 | ||
11016 | @item | |
11017 | @tab reply @samp{} | |
11018 | @tab | |
11019 | When @samp{q}@samp{Rcmd} is not recognized. | |
11020 | ||
0f1f2b0a MS |
11021 | @item symbol lookup |
11022 | @tab @code{qSymbol::} | |
11023 | @tab | |
11024 | Notify the target that @value{GDBN} is prepared to serve symbol lookup | |
11025 | requests. Accept requests from the target for the values of symbols. | |
11026 | @item | |
11027 | @tab | |
11028 | @tab | |
11029 | @item | |
11030 | @tab reply @code{OK} | |
11031 | @tab | |
11032 | The target does not need to look up any (more) symbols. | |
11033 | @item | |
11034 | @tab reply @code{qSymbol:}@var{sym_name} | |
11035 | @tab | |
6826cf00 EZ |
11036 | @sp 2 |
11037 | @noindent | |
0f1f2b0a MS |
11038 | The target requests the value of symbol @var{sym_name} (hex encoded). |
11039 | @value{GDBN} may provide the value by using the | |
11040 | @code{qSymbol:}@var{sym_value}:@var{sym_name} | |
11041 | message, described below. | |
11042 | ||
11043 | @item symbol value | |
11044 | @tab @code{qSymbol:}@var{sym_value}:@var{sym_name} | |
11045 | @tab | |
6826cf00 EZ |
11046 | @sp 1 |
11047 | @noindent | |
0f1f2b0a MS |
11048 | Set the value of SYM_NAME to SYM_VALUE. |
11049 | @item | |
11050 | @tab | |
11051 | @tab | |
11052 | @var{sym_name} (hex encoded) is the name of a symbol whose value | |
11053 | the target has previously requested. | |
11054 | @item | |
11055 | @tab | |
11056 | @tab | |
11057 | @var{sym_value} (hex) is the value for symbol @var{sym_name}. | |
11058 | If @value{GDBN} cannot supply a value for @var{sym_name}, then this | |
11059 | field will be empty. | |
11060 | @item | |
11061 | @tab reply @code{OK} | |
11062 | @tab | |
11063 | The target does not need to look up any (more) symbols. | |
11064 | @item | |
11065 | @tab reply @code{qSymbol:}@var{sym_name} | |
11066 | @tab | |
6826cf00 EZ |
11067 | @sp 2 |
11068 | @noindent | |
0f1f2b0a MS |
11069 | The target requests the value of a new symbol @var{sym_name} (hex encoded). |
11070 | @value{GDBN} will continue to supply the values of symbols (if available), | |
11071 | until the target ceases to request them. | |
11072 | ||
d4f3574e SS |
11073 | @end multitable |
11074 | ||
11075 | The following @samp{g}/@samp{G} packets have previously been defined. | |
11076 | In the below, some thirty-two bit registers are transferred as sixty-four | |
11077 | bits. Those registers should be zero/sign extended (which?) to fill the | |
11078 | space allocated. Register bytes are transfered in target byte order. | |
11079 | The two nibbles within a register byte are transfered most-significant - | |
11080 | least-significant. | |
11081 | ||
11082 | @multitable @columnfractions .5 .5 | |
11083 | ||
11084 | @item MIPS32 | |
11085 | @tab | |
11086 | All registers are transfered as thirty-two bit quantities in the order: | |
11087 | 32 general-purpose; sr; lo; hi; bad; cause; pc; 32 floating-point | |
11088 | registers; fsr; fir; fp. | |
11089 | ||
11090 | @item MIPS64 | |
11091 | @tab | |
11092 | All registers are transfered as sixty-four bit quantities (including | |
11093 | thirty-two bit registers such as @code{sr}). The ordering is the same | |
11094 | as @code{MIPS32}. | |
11095 | ||
11096 | @end multitable | |
11097 | ||
104c1213 JM |
11098 | Example sequence of a target being re-started. Notice how the restart |
11099 | does not get any direct output: | |
11100 | ||
11101 | @example | |
11102 | <- @code{R00} | |
11103 | -> @code{+} | |
11104 | @emph{target restarts} | |
11105 | <- @code{?} | |
11106 | -> @code{+} | |
11107 | -> @code{T001:1234123412341234} | |
11108 | <- @code{+} | |
11109 | @end example | |
11110 | ||
11111 | Example sequence of a target being stepped by a single instruction: | |
11112 | ||
11113 | @example | |
11114 | <- @code{G1445...} | |
11115 | -> @code{+} | |
11116 | <- @code{s} | |
11117 | -> @code{+} | |
11118 | @emph{time passes} | |
11119 | -> @code{T001:1234123412341234} | |
11120 | <- @code{+} | |
11121 | <- @code{g} | |
11122 | -> @code{+} | |
11123 | -> @code{1455...} | |
11124 | <- @code{+} | |
11125 | @end example | |
11126 | ||
6d2ebf8b | 11127 | @node Server |
104c1213 JM |
11128 | @subsubsection Using the @code{gdbserver} program |
11129 | ||
11130 | @kindex gdbserver | |
11131 | @cindex remote connection without stubs | |
11132 | @code{gdbserver} is a control program for Unix-like systems, which | |
11133 | allows you to connect your program with a remote @value{GDBN} via | |
11134 | @code{target remote}---but without linking in the usual debugging stub. | |
11135 | ||
11136 | @code{gdbserver} is not a complete replacement for the debugging stubs, | |
11137 | because it requires essentially the same operating-system facilities | |
11138 | that @value{GDBN} itself does. In fact, a system that can run | |
11139 | @code{gdbserver} to connect to a remote @value{GDBN} could also run | |
11140 | @value{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless, | |
11141 | because it is a much smaller program than @value{GDBN} itself. It is | |
11142 | also easier to port than all of @value{GDBN}, so you may be able to get | |
11143 | started more quickly on a new system by using @code{gdbserver}. | |
11144 | Finally, if you develop code for real-time systems, you may find that | |
11145 | the tradeoffs involved in real-time operation make it more convenient to | |
11146 | do as much development work as possible on another system, for example | |
11147 | by cross-compiling. You can use @code{gdbserver} to make a similar | |
11148 | choice for debugging. | |
11149 | ||
11150 | @value{GDBN} and @code{gdbserver} communicate via either a serial line | |
11151 | or a TCP connection, using the standard @value{GDBN} remote serial | |
11152 | protocol. | |
11153 | ||
11154 | @table @emph | |
11155 | @item On the target machine, | |
11156 | you need to have a copy of the program you want to debug. | |
11157 | @code{gdbserver} does not need your program's symbol table, so you can | |
11158 | strip the program if necessary to save space. @value{GDBN} on the host | |
11159 | system does all the symbol handling. | |
11160 | ||
11161 | To use the server, you must tell it how to communicate with @value{GDBN}; | |
11162 | the name of your program; and the arguments for your program. The | |
11163 | syntax is: | |
11164 | ||
11165 | @smallexample | |
11166 | target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ] | |
11167 | @end smallexample | |
11168 | ||
11169 | @var{comm} is either a device name (to use a serial line) or a TCP | |
11170 | hostname and portnumber. For example, to debug Emacs with the argument | |
11171 | @samp{foo.txt} and communicate with @value{GDBN} over the serial port | |
11172 | @file{/dev/com1}: | |
11173 | ||
11174 | @smallexample | |
11175 | target> gdbserver /dev/com1 emacs foo.txt | |
11176 | @end smallexample | |
11177 | ||
11178 | @code{gdbserver} waits passively for the host @value{GDBN} to communicate | |
11179 | with it. | |
11180 | ||
11181 | To use a TCP connection instead of a serial line: | |
11182 | ||
11183 | @smallexample | |
11184 | target> gdbserver host:2345 emacs foo.txt | |
11185 | @end smallexample | |
11186 | ||
11187 | The only difference from the previous example is the first argument, | |
11188 | specifying that you are communicating with the host @value{GDBN} via | |
11189 | TCP. The @samp{host:2345} argument means that @code{gdbserver} is to | |
11190 | expect a TCP connection from machine @samp{host} to local TCP port 2345. | |
11191 | (Currently, the @samp{host} part is ignored.) You can choose any number | |
11192 | you want for the port number as long as it does not conflict with any | |
11193 | TCP ports already in use on the target system (for example, @code{23} is | |
11194 | reserved for @code{telnet}).@footnote{If you choose a port number that | |
11195 | conflicts with another service, @code{gdbserver} prints an error message | |
d4f3574e | 11196 | and exits.} You must use the same port number with the host @value{GDBN} |
104c1213 JM |
11197 | @code{target remote} command. |
11198 | ||
11199 | @item On the @value{GDBN} host machine, | |
11200 | you need an unstripped copy of your program, since @value{GDBN} needs | |
11201 | symbols and debugging information. Start up @value{GDBN} as usual, | |
11202 | using the name of the local copy of your program as the first argument. | |
11203 | (You may also need the @w{@samp{--baud}} option if the serial line is | |
d4f3574e | 11204 | running at anything other than 9600@dmn{bps}.) After that, use @code{target |
104c1213 JM |
11205 | remote} to establish communications with @code{gdbserver}. Its argument |
11206 | is either a device name (usually a serial device, like | |
11207 | @file{/dev/ttyb}), or a TCP port descriptor in the form | |
11208 | @code{@var{host}:@var{PORT}}. For example: | |
11209 | ||
11210 | @smallexample | |
11211 | (@value{GDBP}) target remote /dev/ttyb | |
11212 | @end smallexample | |
11213 | ||
11214 | @noindent | |
11215 | communicates with the server via serial line @file{/dev/ttyb}, and | |
11216 | ||
11217 | @smallexample | |
11218 | (@value{GDBP}) target remote the-target:2345 | |
11219 | @end smallexample | |
11220 | ||
11221 | @noindent | |
11222 | communicates via a TCP connection to port 2345 on host @w{@file{the-target}}. | |
11223 | For TCP connections, you must start up @code{gdbserver} prior to using | |
11224 | the @code{target remote} command. Otherwise you may get an error whose | |
11225 | text depends on the host system, but which usually looks something like | |
11226 | @samp{Connection refused}. | |
11227 | @end table | |
11228 | ||
6d2ebf8b | 11229 | @node NetWare |
104c1213 JM |
11230 | @subsubsection Using the @code{gdbserve.nlm} program |
11231 | ||
11232 | @kindex gdbserve.nlm | |
11233 | @code{gdbserve.nlm} is a control program for NetWare systems, which | |
11234 | allows you to connect your program with a remote @value{GDBN} via | |
11235 | @code{target remote}. | |
11236 | ||
11237 | @value{GDBN} and @code{gdbserve.nlm} communicate via a serial line, | |
11238 | using the standard @value{GDBN} remote serial protocol. | |
11239 | ||
11240 | @table @emph | |
11241 | @item On the target machine, | |
11242 | you need to have a copy of the program you want to debug. | |
11243 | @code{gdbserve.nlm} does not need your program's symbol table, so you | |
11244 | can strip the program if necessary to save space. @value{GDBN} on the | |
11245 | host system does all the symbol handling. | |
11246 | ||
11247 | To use the server, you must tell it how to communicate with | |
11248 | @value{GDBN}; the name of your program; and the arguments for your | |
11249 | program. The syntax is: | |
11250 | ||
5d161b24 | 11251 | @smallexample |
104c1213 JM |
11252 | load gdbserve [ BOARD=@var{board} ] [ PORT=@var{port} ] |
11253 | [ BAUD=@var{baud} ] @var{program} [ @var{args} @dots{} ] | |
11254 | @end smallexample | |
11255 | ||
11256 | @var{board} and @var{port} specify the serial line; @var{baud} specifies | |
11257 | the baud rate used by the connection. @var{port} and @var{node} default | |
d4f3574e | 11258 | to 0, @var{baud} defaults to 9600@dmn{bps}. |
104c1213 JM |
11259 | |
11260 | For example, to debug Emacs with the argument @samp{foo.txt}and | |
5d161b24 | 11261 | communicate with @value{GDBN} over serial port number 2 or board 1 |
d4f3574e | 11262 | using a 19200@dmn{bps} connection: |
104c1213 JM |
11263 | |
11264 | @smallexample | |
11265 | load gdbserve BOARD=1 PORT=2 BAUD=19200 emacs foo.txt | |
11266 | @end smallexample | |
11267 | ||
11268 | @item On the @value{GDBN} host machine, | |
11269 | you need an unstripped copy of your program, since @value{GDBN} needs | |
11270 | symbols and debugging information. Start up @value{GDBN} as usual, | |
11271 | using the name of the local copy of your program as the first argument. | |
11272 | (You may also need the @w{@samp{--baud}} option if the serial line is | |
d4f3574e | 11273 | running at anything other than 9600@dmn{bps}. After that, use @code{target |
104c1213 JM |
11274 | remote} to establish communications with @code{gdbserve.nlm}. Its |
11275 | argument is a device name (usually a serial device, like | |
11276 | @file{/dev/ttyb}). For example: | |
11277 | ||
11278 | @smallexample | |
11279 | (@value{GDBP}) target remote /dev/ttyb | |
11280 | @end smallexample | |
11281 | ||
11282 | @noindent | |
11283 | communications with the server via serial line @file{/dev/ttyb}. | |
11284 | @end table | |
11285 | ||
6d2ebf8b | 11286 | @node KOD |
104c1213 JM |
11287 | @section Kernel Object Display |
11288 | ||
11289 | @cindex kernel object display | |
11290 | @cindex kernel object | |
11291 | @cindex KOD | |
11292 | ||
11293 | Some targets support kernel object display. Using this facility, | |
11294 | @value{GDBN} communicates specially with the underlying operating system | |
11295 | and can display information about operating system-level objects such as | |
11296 | mutexes and other synchronization objects. Exactly which objects can be | |
11297 | displayed is determined on a per-OS basis. | |
11298 | ||
11299 | Use the @code{set os} command to set the operating system. This tells | |
11300 | @value{GDBN} which kernel object display module to initialize: | |
11301 | ||
11302 | @example | |
2df3850c | 11303 | (@value{GDBP}) set os cisco |
104c1213 JM |
11304 | @end example |
11305 | ||
11306 | If @code{set os} succeeds, @value{GDBN} will display some information | |
11307 | about the operating system, and will create a new @code{info} command | |
11308 | which can be used to query the target. The @code{info} command is named | |
11309 | after the operating system: | |
11310 | ||
11311 | @example | |
2df3850c | 11312 | (@value{GDBP}) info cisco |
104c1213 JM |
11313 | List of Cisco Kernel Objects |
11314 | Object Description | |
11315 | any Any and all objects | |
11316 | @end example | |
11317 | ||
11318 | Further subcommands can be used to query about particular objects known | |
11319 | by the kernel. | |
11320 | ||
11321 | There is currently no way to determine whether a given operating system | |
96baa820 JM |
11322 | is supported other than to try it. |
11323 | ||
11324 | ||
6d2ebf8b | 11325 | @node Configurations |
104c1213 JM |
11326 | @chapter Configuration-Specific Information |
11327 | ||
11328 | While nearly all @value{GDBN} commands are available for all native and | |
11329 | cross versions of the debugger, there are some exceptions. This chapter | |
11330 | describes things that are only available in certain configurations. | |
11331 | ||
11332 | There are three major categories of configurations: native | |
11333 | configurations, where the host and target are the same, embedded | |
11334 | operating system configurations, which are usually the same for several | |
11335 | different processor architectures, and bare embedded processors, which | |
11336 | are quite different from each other. | |
11337 | ||
11338 | @menu | |
11339 | * Native:: | |
11340 | * Embedded OS:: | |
11341 | * Embedded Processors:: | |
11342 | * Architectures:: | |
11343 | @end menu | |
11344 | ||
6d2ebf8b | 11345 | @node Native |
104c1213 JM |
11346 | @section Native |
11347 | ||
11348 | This section describes details specific to particular native | |
11349 | configurations. | |
11350 | ||
11351 | @menu | |
11352 | * HP-UX:: HP-UX | |
11353 | * SVR4 Process Information:: SVR4 process information | |
9f20bf26 | 11354 | * DJGPP Native:: Features specific to the DJGPP port |
104c1213 JM |
11355 | @end menu |
11356 | ||
6d2ebf8b | 11357 | @node HP-UX |
104c1213 JM |
11358 | @subsection HP-UX |
11359 | ||
11360 | On HP-UX systems, if you refer to a function or variable name that | |
11361 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
11362 | name first, before it searches for a convenience variable. | |
11363 | ||
6d2ebf8b | 11364 | @node SVR4 Process Information |
104c1213 JM |
11365 | @subsection SVR4 process information |
11366 | ||
11367 | @kindex /proc | |
11368 | @cindex process image | |
11369 | ||
11370 | Many versions of SVR4 provide a facility called @samp{/proc} that can be | |
11371 | used to examine the image of a running process using file-system | |
11372 | subroutines. If @value{GDBN} is configured for an operating system with | |
11373 | this facility, the command @code{info proc} is available to report on | |
11374 | several kinds of information about the process running your program. | |
11375 | @code{info proc} works only on SVR4 systems that include the | |
11376 | @code{procfs} code. This includes OSF/1 (Digital Unix), Solaris, Irix, | |
11377 | and Unixware, but not HP-UX or Linux, for example. | |
11378 | ||
11379 | @table @code | |
11380 | @kindex info proc | |
11381 | @item info proc | |
11382 | Summarize available information about the process. | |
11383 | ||
11384 | @kindex info proc mappings | |
11385 | @item info proc mappings | |
11386 | Report on the address ranges accessible in the program, with information | |
11387 | on whether your program may read, write, or execute each range. | |
f6680716 MS |
11388 | @ignore |
11389 | @comment These sub-options of 'info proc' were not included when | |
11390 | @comment procfs.c was re-written. Keep their descriptions around | |
11391 | @comment against the day when someone finds the time to put them back in. | |
104c1213 JM |
11392 | @kindex info proc times |
11393 | @item info proc times | |
11394 | Starting time, user CPU time, and system CPU time for your program and | |
11395 | its children. | |
11396 | ||
11397 | @kindex info proc id | |
11398 | @item info proc id | |
11399 | Report on the process IDs related to your program: its own process ID, | |
11400 | the ID of its parent, the process group ID, and the session ID. | |
11401 | ||
11402 | @kindex info proc status | |
11403 | @item info proc status | |
11404 | General information on the state of the process. If the process is | |
11405 | stopped, this report includes the reason for stopping, and any signal | |
11406 | received. | |
11407 | ||
11408 | @item info proc all | |
11409 | Show all the above information about the process. | |
f6680716 | 11410 | @end ignore |
104c1213 JM |
11411 | @end table |
11412 | ||
9f20bf26 EZ |
11413 | @node DJGPP Native |
11414 | @subsection Features for Debugging @sc{djgpp} Programs | |
11415 | @cindex @sc{djgpp} debugging | |
11416 | @cindex native @sc{djgpp} debugging | |
11417 | @cindex MS-DOS-specific commands | |
11418 | ||
11419 | @sc{djgpp} is the port of @sc{gnu} development tools to MS-DOS and | |
11420 | MS-Windows. @sc{djgpp} programs are 32-bit protected-mode programs | |
11421 | that use the @dfn{DPMI} (DOS Protected-Mode Interface) API to run on | |
11422 | top of real-mode DOS systems and their emulations. | |
11423 | ||
11424 | @value{GDBN} supports native debugging of @sc{djgpp} programs, and | |
11425 | defines a few commands specific to the @sc{djgpp} port. This | |
11426 | subsection describes those commands. | |
11427 | ||
11428 | @table @code | |
11429 | @kindex info dos | |
11430 | @item info dos | |
11431 | This is a prefix of @sc{djgpp}-specific commands which print | |
11432 | information about the target system and important OS structures. | |
11433 | ||
11434 | @kindex sysinfo | |
11435 | @cindex MS-DOS system info | |
11436 | @cindex free memory information (MS-DOS) | |
11437 | @item info dos sysinfo | |
11438 | This command displays assorted information about the underlying | |
11439 | platform: the CPU type and features, the OS version and flavor, the | |
11440 | DPMI version, and the available conventional and DPMI memory. | |
11441 | ||
11442 | @cindex GDT | |
11443 | @cindex LDT | |
11444 | @cindex IDT | |
11445 | @cindex segment descriptor tables | |
11446 | @cindex descriptor tables display | |
11447 | @item info dos gdt | |
11448 | @itemx info dos ldt | |
11449 | @itemx info dos idt | |
11450 | These 3 commands display entries from, respectively, Global, Local, | |
11451 | and Interrupt Descriptor Tables (GDT, LDT, and IDT). The descriptor | |
11452 | tables are data structures which store a descriptor for each segment | |
11453 | that is currently in use. The segment's selector is an index into a | |
11454 | descriptor table; the table entry for that index holds the | |
11455 | descriptor's base address and limit, and its attributes and access | |
11456 | rights. | |
11457 | ||
11458 | A typical @sc{djgpp} program uses 3 segments: a code segment, a data | |
11459 | segment (used for both data and the stack), and a DOS segment (which | |
11460 | allows access to DOS/BIOS data structures and absolute addresses in | |
11461 | conventional memory). However, the DPMI host will usually define | |
11462 | additional segments in order to support the DPMI environment. | |
11463 | ||
11464 | @cindex garbled pointers | |
11465 | These commands allow to display entries from the descriptor tables. | |
11466 | Without an argument, all entries from the specified table are | |
11467 | displayed. An argument, which should be an integer expression, means | |
11468 | display a single entry whose index is given by the argument. For | |
11469 | example, here's a convenient way to display information about the | |
11470 | debugged program's data segment: | |
11471 | ||
11472 | @smallexample | |
11473 | (@value{GDBP}) info dos ldt $ds | |
11474 | 0x13f: base=0x11970000 limit=0x0009ffff 32-Bit Data (Read/Write, Exp-up) | |
11475 | @end smallexample | |
11476 | ||
11477 | @noindent | |
11478 | This comes in handy when you want to see whether a pointer is outside | |
11479 | the data segment's limit (i.e.@: @dfn{garbled}). | |
11480 | ||
11481 | @cindex page tables display (MS-DOS) | |
11482 | @item info dos pde | |
11483 | @itemx info dos pte | |
11484 | These two commands display entries from, respectively, the Page | |
11485 | Directory and the Page Tables. Page Directories and Page Tables are | |
11486 | data structures which control how virtual memory addresses are mapped | |
11487 | into physical addresses. A Page Table includes an entry for every | |
11488 | page of memory that is mapped into the program's address space; there | |
11489 | may be several Page Tables, each one holding up to 4096 entries. A | |
11490 | Page Directory has up to 4096 entries, one each for every Page Table | |
11491 | that is currently in use. | |
11492 | ||
11493 | Without an argument, @kbd{info dos pde} displays the entire Page | |
11494 | Directory, and @kbd{info dos pte} displays all the entries in all of | |
11495 | the Page Tables. An argument, an integer expression, given to the | |
11496 | @kbd{info dos pde} command means display only that entry from the Page | |
11497 | Directory table. An argument given to the @kbd{info dos pte} command | |
11498 | means display entries from a single Page Table, the one pointed to by | |
11499 | the specified entry in the Page Directory. | |
11500 | ||
11501 | These commands are useful when your program uses @dfn{DMA} (Direct | |
11502 | Memory Access), which needs physical addresses to program the DMA | |
11503 | controller. | |
11504 | ||
11505 | These commands are supported only with some DPMI servers. | |
11506 | ||
11507 | @cindex physical address from linear address | |
11508 | @item info dos address-pte | |
11509 | This command displays the Page Table entry for a specified linear | |
11510 | address. The argument linear address should already have the | |
11511 | appropriate segment's base address added to it, because this command | |
11512 | accepts addresses which may belong to @emph{any} segment. For | |
11513 | example, here's how to display the Page Table entry for the page where | |
11514 | the variable @code{i} is stored: | |
11515 | ||
11516 | @smallexample | |
11517 | (@value{GDBP}) info dos address-pte __djgpp_base_address + (char *)&i | |
11518 | Page Table entry for address 0x11a00d30: | |
11519 | Base=0x02698000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0xd30 | |
11520 | @end smallexample | |
11521 | ||
11522 | @noindent | |
11523 | This says that @code{i} is stored at offset @code{0xd30} from the page | |
11524 | whose physical base address is @code{0x02698000}, and prints all the | |
11525 | attributes of that page. | |
11526 | ||
11527 | Note that you must cast the addresses of variables to a @code{char *}, | |
11528 | since otherwise the value of @code{__djgpp_base_address}, the base | |
11529 | address of all variables and functions in a @sc{djgpp} program, will | |
11530 | be added using the rules of C pointer arithmetics: if @code{i} is | |
11531 | declared an @code{int}, @value{GDBN} will add 4 times the value of | |
11532 | @code{__djgpp_base_address} to the address of @code{i}. | |
11533 | ||
11534 | Here's another example, it displays the Page Table entry for the | |
11535 | transfer buffer: | |
11536 | ||
11537 | @smallexample | |
11538 | (@value{GDBP}) info dos address-pte *((unsigned *)&_go32_info_block + 3) | |
11539 | Page Table entry for address 0x29110: | |
11540 | Base=0x00029000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0x110 | |
11541 | @end smallexample | |
11542 | ||
11543 | @noindent | |
11544 | (The @code{+ 3} offset is because the transfer buffer's address is the | |
11545 | 3rd member of the @code{_go32_info_block} structure.) The output of | |
11546 | this command clearly shows that addresses in conventional memory are | |
11547 | mapped 1:1, i.e.@: the physical and linear addresses are identical. | |
11548 | ||
11549 | This command is supported only with some DPMI servers. | |
11550 | @end table | |
11551 | ||
6d2ebf8b | 11552 | @node Embedded OS |
104c1213 JM |
11553 | @section Embedded Operating Systems |
11554 | ||
11555 | This section describes configurations involving the debugging of | |
11556 | embedded operating systems that are available for several different | |
11557 | architectures. | |
11558 | ||
11559 | @menu | |
11560 | * VxWorks:: Using @value{GDBN} with VxWorks | |
11561 | @end menu | |
11562 | ||
11563 | @value{GDBN} includes the ability to debug programs running on | |
11564 | various real-time operating systems. | |
11565 | ||
6d2ebf8b | 11566 | @node VxWorks |
104c1213 JM |
11567 | @subsection Using @value{GDBN} with VxWorks |
11568 | ||
11569 | @cindex VxWorks | |
11570 | ||
11571 | @table @code | |
11572 | ||
11573 | @kindex target vxworks | |
11574 | @item target vxworks @var{machinename} | |
11575 | A VxWorks system, attached via TCP/IP. The argument @var{machinename} | |
11576 | is the target system's machine name or IP address. | |
11577 | ||
11578 | @end table | |
11579 | ||
11580 | On VxWorks, @code{load} links @var{filename} dynamically on the | |
11581 | current target system as well as adding its symbols in @value{GDBN}. | |
11582 | ||
11583 | @value{GDBN} enables developers to spawn and debug tasks running on networked | |
11584 | VxWorks targets from a Unix host. Already-running tasks spawned from | |
11585 | the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on | |
11586 | both the Unix host and on the VxWorks target. The program | |
d4f3574e | 11587 | @code{@value{GDBP}} is installed and executed on the Unix host. (It may be |
104c1213 | 11588 | installed with the name @code{vxgdb}, to distinguish it from a |
96a2c332 | 11589 | @value{GDBN} for debugging programs on the host itself.) |
104c1213 JM |
11590 | |
11591 | @table @code | |
11592 | @item VxWorks-timeout @var{args} | |
11593 | @kindex vxworks-timeout | |
5d161b24 DB |
11594 | All VxWorks-based targets now support the option @code{vxworks-timeout}. |
11595 | This option is set by the user, and @var{args} represents the number of | |
11596 | seconds @value{GDBN} waits for responses to rpc's. You might use this if | |
11597 | your VxWorks target is a slow software simulator or is on the far side | |
104c1213 JM |
11598 | of a thin network line. |
11599 | @end table | |
11600 | ||
11601 | The following information on connecting to VxWorks was current when | |
11602 | this manual was produced; newer releases of VxWorks may use revised | |
11603 | procedures. | |
11604 | ||
11605 | @kindex INCLUDE_RDB | |
11606 | To use @value{GDBN} with VxWorks, you must rebuild your VxWorks kernel | |
11607 | to include the remote debugging interface routines in the VxWorks | |
11608 | library @file{rdb.a}. To do this, define @code{INCLUDE_RDB} in the | |
11609 | VxWorks configuration file @file{configAll.h} and rebuild your VxWorks | |
11610 | kernel. The resulting kernel contains @file{rdb.a}, and spawns the | |
11611 | source debugging task @code{tRdbTask} when VxWorks is booted. For more | |
11612 | information on configuring and remaking VxWorks, see the manufacturer's | |
11613 | manual. | |
11614 | @c VxWorks, see the @cite{VxWorks Programmer's Guide}. | |
11615 | ||
11616 | Once you have included @file{rdb.a} in your VxWorks system image and set | |
11617 | your Unix execution search path to find @value{GDBN}, you are ready to | |
96a2c332 SS |
11618 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} (or |
11619 | @code{vxgdb}, depending on your installation). | |
104c1213 JM |
11620 | |
11621 | @value{GDBN} comes up showing the prompt: | |
11622 | ||
11623 | @example | |
11624 | (vxgdb) | |
11625 | @end example | |
11626 | ||
11627 | @menu | |
11628 | * VxWorks Connection:: Connecting to VxWorks | |
11629 | * VxWorks Download:: VxWorks download | |
11630 | * VxWorks Attach:: Running tasks | |
11631 | @end menu | |
11632 | ||
6d2ebf8b | 11633 | @node VxWorks Connection |
104c1213 JM |
11634 | @subsubsection Connecting to VxWorks |
11635 | ||
11636 | The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the | |
11637 | network. To connect to a target whose host name is ``@code{tt}'', type: | |
11638 | ||
11639 | @example | |
11640 | (vxgdb) target vxworks tt | |
11641 | @end example | |
11642 | ||
11643 | @need 750 | |
11644 | @value{GDBN} displays messages like these: | |
11645 | ||
11646 | @smallexample | |
5d161b24 | 11647 | Attaching remote machine across net... |
104c1213 JM |
11648 | Connected to tt. |
11649 | @end smallexample | |
11650 | ||
11651 | @need 1000 | |
11652 | @value{GDBN} then attempts to read the symbol tables of any object modules | |
11653 | loaded into the VxWorks target since it was last booted. @value{GDBN} locates | |
11654 | these files by searching the directories listed in the command search | |
11655 | path (@pxref{Environment, ,Your program's environment}); if it fails | |
11656 | to find an object file, it displays a message such as: | |
11657 | ||
11658 | @example | |
11659 | prog.o: No such file or directory. | |
11660 | @end example | |
11661 | ||
11662 | When this happens, add the appropriate directory to the search path with | |
11663 | the @value{GDBN} command @code{path}, and execute the @code{target} | |
11664 | command again. | |
11665 | ||
6d2ebf8b | 11666 | @node VxWorks Download |
104c1213 JM |
11667 | @subsubsection VxWorks download |
11668 | ||
11669 | @cindex download to VxWorks | |
11670 | If you have connected to the VxWorks target and you want to debug an | |
11671 | object that has not yet been loaded, you can use the @value{GDBN} | |
11672 | @code{load} command to download a file from Unix to VxWorks | |
11673 | incrementally. The object file given as an argument to the @code{load} | |
11674 | command is actually opened twice: first by the VxWorks target in order | |
11675 | to download the code, then by @value{GDBN} in order to read the symbol | |
11676 | table. This can lead to problems if the current working directories on | |
11677 | the two systems differ. If both systems have NFS mounted the same | |
11678 | filesystems, you can avoid these problems by using absolute paths. | |
11679 | Otherwise, it is simplest to set the working directory on both systems | |
11680 | to the directory in which the object file resides, and then to reference | |
11681 | the file by its name, without any path. For instance, a program | |
11682 | @file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks | |
11683 | and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this | |
11684 | program, type this on VxWorks: | |
11685 | ||
11686 | @example | |
11687 | -> cd "@var{vxpath}/vw/demo/rdb" | |
11688 | @end example | |
d4f3574e SS |
11689 | |
11690 | @noindent | |
104c1213 JM |
11691 | Then, in @value{GDBN}, type: |
11692 | ||
11693 | @example | |
5d161b24 | 11694 | (vxgdb) cd @var{hostpath}/vw/demo/rdb |
104c1213 JM |
11695 | (vxgdb) load prog.o |
11696 | @end example | |
11697 | ||
11698 | @value{GDBN} displays a response similar to this: | |
11699 | ||
11700 | @smallexample | |
11701 | Reading symbol data from wherever/vw/demo/rdb/prog.o... done. | |
11702 | @end smallexample | |
11703 | ||
11704 | You can also use the @code{load} command to reload an object module | |
11705 | after editing and recompiling the corresponding source file. Note that | |
11706 | this makes @value{GDBN} delete all currently-defined breakpoints, | |
11707 | auto-displays, and convenience variables, and to clear the value | |
11708 | history. (This is necessary in order to preserve the integrity of | |
d4f3574e | 11709 | debugger's data structures that reference the target system's symbol |
104c1213 JM |
11710 | table.) |
11711 | ||
6d2ebf8b | 11712 | @node VxWorks Attach |
104c1213 JM |
11713 | @subsubsection Running tasks |
11714 | ||
11715 | @cindex running VxWorks tasks | |
11716 | You can also attach to an existing task using the @code{attach} command as | |
11717 | follows: | |
11718 | ||
11719 | @example | |
11720 | (vxgdb) attach @var{task} | |
11721 | @end example | |
11722 | ||
11723 | @noindent | |
11724 | where @var{task} is the VxWorks hexadecimal task ID. The task can be running | |
11725 | or suspended when you attach to it. Running tasks are suspended at | |
11726 | the time of attachment. | |
11727 | ||
6d2ebf8b | 11728 | @node Embedded Processors |
104c1213 JM |
11729 | @section Embedded Processors |
11730 | ||
11731 | This section goes into details specific to particular embedded | |
11732 | configurations. | |
11733 | ||
7d86b5d5 AC |
11734 | |
11735 | @c OBSOLETE * A29K Embedded:: AMD A29K Embedded | |
104c1213 | 11736 | @menu |
104c1213 JM |
11737 | * ARM:: ARM |
11738 | * H8/300:: Hitachi H8/300 | |
11739 | * H8/500:: Hitachi H8/500 | |
11740 | * i960:: Intel i960 | |
11741 | * M32R/D:: Mitsubishi M32R/D | |
11742 | * M68K:: Motorola M68K | |
11743 | * M88K:: Motorola M88K | |
11744 | * MIPS Embedded:: MIPS Embedded | |
11745 | * PA:: HP PA Embedded | |
11746 | * PowerPC: PowerPC | |
11747 | * SH:: Hitachi SH | |
11748 | * Sparclet:: Tsqware Sparclet | |
11749 | * Sparclite:: Fujitsu Sparclite | |
11750 | * ST2000:: Tandem ST2000 | |
11751 | * Z8000:: Zilog Z8000 | |
11752 | @end menu | |
11753 | ||
7d86b5d5 AC |
11754 | @c OBSOLETE @node A29K Embedded |
11755 | @c OBSOLETE @subsection AMD A29K Embedded | |
11756 | @c OBSOLETE | |
11757 | @c OBSOLETE @menu | |
11758 | @c OBSOLETE * A29K UDI:: | |
11759 | @c OBSOLETE * A29K EB29K:: | |
11760 | @c OBSOLETE * Comms (EB29K):: Communications setup | |
11761 | @c OBSOLETE * gdb-EB29K:: EB29K cross-debugging | |
11762 | @c OBSOLETE * Remote Log:: Remote log | |
11763 | @c OBSOLETE @end menu | |
11764 | @c OBSOLETE | |
11765 | @c OBSOLETE @table @code | |
11766 | @c OBSOLETE | |
11767 | @c OBSOLETE @kindex target adapt | |
11768 | @c OBSOLETE @item target adapt @var{dev} | |
11769 | @c OBSOLETE Adapt monitor for A29K. | |
11770 | @c OBSOLETE | |
11771 | @c OBSOLETE @kindex target amd-eb | |
11772 | @c OBSOLETE @item target amd-eb @var{dev} @var{speed} @var{PROG} | |
11773 | @c OBSOLETE @cindex AMD EB29K | |
11774 | @c OBSOLETE Remote PC-resident AMD EB29K board, attached over serial lines. | |
11775 | @c OBSOLETE @var{dev} is the serial device, as for @code{target remote}; | |
11776 | @c OBSOLETE @var{speed} allows you to specify the linespeed; and @var{PROG} is the | |
11777 | @c OBSOLETE name of the program to be debugged, as it appears to DOS on the PC. | |
11778 | @c OBSOLETE @xref{A29K EB29K, ,EBMON protocol for AMD29K}. | |
11779 | @c OBSOLETE | |
11780 | @c OBSOLETE @end table | |
11781 | @c OBSOLETE | |
11782 | @c OBSOLETE @node A29K UDI | |
11783 | @c OBSOLETE @subsubsection A29K UDI | |
11784 | @c OBSOLETE | |
11785 | @c OBSOLETE @cindex UDI | |
11786 | @c OBSOLETE @cindex AMD29K via UDI | |
11787 | @c OBSOLETE | |
11788 | @c OBSOLETE @value{GDBN} supports AMD's UDI (``Universal Debugger Interface'') | |
11789 | @c OBSOLETE protocol for debugging the a29k processor family. To use this | |
11790 | @c OBSOLETE configuration with AMD targets running the MiniMON monitor, you need the | |
11791 | @c OBSOLETE program @code{MONTIP}, available from AMD at no charge. You can also | |
11792 | @c OBSOLETE use @value{GDBN} with the UDI-conformant a29k simulator program | |
11793 | @c OBSOLETE @code{ISSTIP}, also available from AMD. | |
11794 | @c OBSOLETE | |
11795 | @c OBSOLETE @table @code | |
11796 | @c OBSOLETE @item target udi @var{keyword} | |
11797 | @c OBSOLETE @kindex udi | |
11798 | @c OBSOLETE Select the UDI interface to a remote a29k board or simulator, where | |
11799 | @c OBSOLETE @var{keyword} is an entry in the AMD configuration file @file{udi_soc}. | |
11800 | @c OBSOLETE This file contains keyword entries which specify parameters used to | |
11801 | @c OBSOLETE connect to a29k targets. If the @file{udi_soc} file is not in your | |
11802 | @c OBSOLETE working directory, you must set the environment variable @samp{UDICONF} | |
11803 | @c OBSOLETE to its pathname. | |
11804 | @c OBSOLETE @end table | |
11805 | @c OBSOLETE | |
11806 | @c OBSOLETE @node A29K EB29K | |
11807 | @c OBSOLETE @subsubsection EBMON protocol for AMD29K | |
11808 | @c OBSOLETE | |
11809 | @c OBSOLETE @cindex EB29K board | |
11810 | @c OBSOLETE @cindex running 29K programs | |
11811 | @c OBSOLETE | |
11812 | @c OBSOLETE AMD distributes a 29K development board meant to fit in a PC, together | |
11813 | @c OBSOLETE with a DOS-hosted monitor program called @code{EBMON}. As a shorthand | |
11814 | @c OBSOLETE term, this development system is called the ``EB29K''. To use | |
11815 | @c OBSOLETE @value{GDBN} from a Unix system to run programs on the EB29K board, you | |
11816 | @c OBSOLETE must first connect a serial cable between the PC (which hosts the EB29K | |
11817 | @c OBSOLETE board) and a serial port on the Unix system. In the following, we | |
11818 | @c OBSOLETE assume you've hooked the cable between the PC's @file{COM1} port and | |
11819 | @c OBSOLETE @file{/dev/ttya} on the Unix system. | |
11820 | @c OBSOLETE | |
11821 | @c OBSOLETE @node Comms (EB29K) | |
11822 | @c OBSOLETE @subsubsection Communications setup | |
11823 | @c OBSOLETE | |
11824 | @c OBSOLETE The next step is to set up the PC's port, by doing something like this | |
11825 | @c OBSOLETE in DOS on the PC: | |
11826 | @c OBSOLETE | |
11827 | @c OBSOLETE @example | |
11828 | @c OBSOLETE C:\> MODE com1:9600,n,8,1,none | |
11829 | @c OBSOLETE @end example | |
11830 | @c OBSOLETE | |
11831 | @c OBSOLETE @noindent | |
11832 | @c OBSOLETE This example---run on an MS DOS 4.0 system---sets the PC port to 9600 | |
11833 | @c OBSOLETE bps, no parity, eight data bits, one stop bit, and no ``retry'' action; | |
11834 | @c OBSOLETE you must match the communications parameters when establishing the Unix | |
11835 | @c OBSOLETE end of the connection as well. | |
11836 | @c OBSOLETE @c FIXME: Who knows what this "no retry action" crud from the DOS manual may | |
11837 | @c OBSOLETE @c mean? It's optional; leave it out? ---doc@cygnus.com, 25feb91 | |
11838 | @c OBSOLETE @c | |
11839 | @c OBSOLETE @c It's optional, but it's unwise to omit it: who knows what is the | |
11840 | @c OBSOLETE @c default value set when the DOS machines boots? "No retry" means that | |
11841 | @c OBSOLETE @c the DOS serial device driver won't retry the operation if it fails; | |
11842 | @c OBSOLETE @c I understand that this is needed because the GDB serial protocol | |
11843 | @c OBSOLETE @c handles any errors and retransmissions itself. ---Eli Zaretskii, 3sep99 | |
11844 | @c OBSOLETE | |
11845 | @c OBSOLETE To give control of the PC to the Unix side of the serial line, type | |
11846 | @c OBSOLETE the following at the DOS console: | |
11847 | @c OBSOLETE | |
11848 | @c OBSOLETE @example | |
11849 | @c OBSOLETE C:\> CTTY com1 | |
11850 | @c OBSOLETE @end example | |
11851 | @c OBSOLETE | |
11852 | @c OBSOLETE @noindent | |
11853 | @c OBSOLETE (Later, if you wish to return control to the DOS console, you can use | |
11854 | @c OBSOLETE the command @code{CTTY con}---but you must send it over the device that | |
11855 | @c OBSOLETE had control, in our example over the @file{COM1} serial line.) | |
11856 | @c OBSOLETE | |
11857 | @c OBSOLETE From the Unix host, use a communications program such as @code{tip} or | |
11858 | @c OBSOLETE @code{cu} to communicate with the PC; for example, | |
11859 | @c OBSOLETE | |
11860 | @c OBSOLETE @example | |
11861 | @c OBSOLETE cu -s 9600 -l /dev/ttya | |
11862 | @c OBSOLETE @end example | |
11863 | @c OBSOLETE | |
11864 | @c OBSOLETE @noindent | |
11865 | @c OBSOLETE The @code{cu} options shown specify, respectively, the linespeed and the | |
11866 | @c OBSOLETE serial port to use. If you use @code{tip} instead, your command line | |
11867 | @c OBSOLETE may look something like the following: | |
11868 | @c OBSOLETE | |
11869 | @c OBSOLETE @example | |
11870 | @c OBSOLETE tip -9600 /dev/ttya | |
11871 | @c OBSOLETE @end example | |
11872 | @c OBSOLETE | |
11873 | @c OBSOLETE @noindent | |
11874 | @c OBSOLETE Your system may require a different name where we show | |
11875 | @c OBSOLETE @file{/dev/ttya} as the argument to @code{tip}. The communications | |
11876 | @c OBSOLETE parameters, including which port to use, are associated with the | |
11877 | @c OBSOLETE @code{tip} argument in the ``remote'' descriptions file---normally the | |
11878 | @c OBSOLETE system table @file{/etc/remote}. | |
11879 | @c OBSOLETE @c FIXME: What if anything needs doing to match the "n,8,1,none" part of | |
11880 | @c OBSOLETE @c the DOS side's comms setup? cu can support -o (odd | |
11881 | @c OBSOLETE @c parity), -e (even parity)---apparently no settings for no parity or | |
11882 | @c OBSOLETE @c for character size. Taken from stty maybe...? John points out tip | |
11883 | @c OBSOLETE @c can set these as internal variables, eg ~s parity=none; man stty | |
11884 | @c OBSOLETE @c suggests that it *might* work to stty these options with stdin or | |
11885 | @c OBSOLETE @c stdout redirected... ---doc@cygnus.com, 25feb91 | |
11886 | @c OBSOLETE @c | |
11887 | @c OBSOLETE @c There's nothing to be done for the "none" part of the DOS MODE | |
11888 | @c OBSOLETE @c command. The rest of the parameters should be matched by the | |
11889 | @c OBSOLETE @c baudrate, bits, and parity used by the Unix side. ---Eli Zaretskii, 3Sep99 | |
11890 | @c OBSOLETE | |
11891 | @c OBSOLETE @kindex EBMON | |
11892 | @c OBSOLETE Using the @code{tip} or @code{cu} connection, change the DOS working | |
11893 | @c OBSOLETE directory to the directory containing a copy of your 29K program, then | |
11894 | @c OBSOLETE start the PC program @code{EBMON} (an EB29K control program supplied | |
11895 | @c OBSOLETE with your board by AMD). You should see an initial display from | |
11896 | @c OBSOLETE @code{EBMON} similar to the one that follows, ending with the | |
11897 | @c OBSOLETE @code{EBMON} prompt @samp{#}--- | |
11898 | @c OBSOLETE | |
11899 | @c OBSOLETE @example | |
11900 | @c OBSOLETE C:\> G: | |
11901 | @c OBSOLETE | |
11902 | @c OBSOLETE G:\> CD \usr\joe\work29k | |
11903 | @c OBSOLETE | |
11904 | @c OBSOLETE G:\USR\JOE\WORK29K> EBMON | |
11905 | @c OBSOLETE Am29000 PC Coprocessor Board Monitor, version 3.0-18 | |
11906 | @c OBSOLETE Copyright 1990 Advanced Micro Devices, Inc. | |
11907 | @c OBSOLETE Written by Gibbons and Associates, Inc. | |
11908 | @c OBSOLETE | |
11909 | @c OBSOLETE Enter '?' or 'H' for help | |
11910 | @c OBSOLETE | |
11911 | @c OBSOLETE PC Coprocessor Type = EB29K | |
11912 | @c OBSOLETE I/O Base = 0x208 | |
11913 | @c OBSOLETE Memory Base = 0xd0000 | |
11914 | @c OBSOLETE | |
11915 | @c OBSOLETE Data Memory Size = 2048KB | |
11916 | @c OBSOLETE Available I-RAM Range = 0x8000 to 0x1fffff | |
11917 | @c OBSOLETE Available D-RAM Range = 0x80002000 to 0x801fffff | |
11918 | @c OBSOLETE | |
11919 | @c OBSOLETE PageSize = 0x400 | |
11920 | @c OBSOLETE Register Stack Size = 0x800 | |
11921 | @c OBSOLETE Memory Stack Size = 0x1800 | |
11922 | @c OBSOLETE | |
11923 | @c OBSOLETE CPU PRL = 0x3 | |
11924 | @c OBSOLETE Am29027 Available = No | |
11925 | @c OBSOLETE Byte Write Available = Yes | |
11926 | @c OBSOLETE | |
11927 | @c OBSOLETE # ~. | |
11928 | @c OBSOLETE @end example | |
11929 | @c OBSOLETE | |
11930 | @c OBSOLETE Then exit the @code{cu} or @code{tip} program (done in the example by | |
11931 | @c OBSOLETE typing @code{~.} at the @code{EBMON} prompt). @code{EBMON} keeps | |
11932 | @c OBSOLETE running, ready for @value{GDBN} to take over. | |
11933 | @c OBSOLETE | |
11934 | @c OBSOLETE For this example, we've assumed what is probably the most convenient | |
11935 | @c OBSOLETE way to make sure the same 29K program is on both the PC and the Unix | |
11936 | @c OBSOLETE system: a PC/NFS connection that establishes ``drive @file{G:}'' on the | |
11937 | @c OBSOLETE PC as a file system on the Unix host. If you do not have PC/NFS or | |
11938 | @c OBSOLETE something similar connecting the two systems, you must arrange some | |
11939 | @c OBSOLETE other way---perhaps floppy-disk transfer---of getting the 29K program | |
11940 | @c OBSOLETE from the Unix system to the PC; @value{GDBN} does @emph{not} download it over the | |
11941 | @c OBSOLETE serial line. | |
11942 | @c OBSOLETE | |
11943 | @c OBSOLETE @node gdb-EB29K | |
11944 | @c OBSOLETE @subsubsection EB29K cross-debugging | |
11945 | @c OBSOLETE | |
11946 | @c OBSOLETE Finally, @code{cd} to the directory containing an image of your 29K | |
11947 | @c OBSOLETE program on the Unix system, and start @value{GDBN}---specifying as argument the | |
11948 | @c OBSOLETE name of your 29K program: | |
11949 | @c OBSOLETE | |
11950 | @c OBSOLETE @example | |
11951 | @c OBSOLETE cd /usr/joe/work29k | |
11952 | @c OBSOLETE @value{GDBP} myfoo | |
11953 | @c OBSOLETE @end example | |
11954 | @c OBSOLETE | |
11955 | @c OBSOLETE @need 500 | |
11956 | @c OBSOLETE Now you can use the @code{target} command: | |
11957 | @c OBSOLETE | |
11958 | @c OBSOLETE @example | |
11959 | @c OBSOLETE target amd-eb /dev/ttya 9600 MYFOO | |
11960 | @c OBSOLETE @c FIXME: test above 'target amd-eb' as spelled, with caps! caps are meant to | |
11961 | @c OBSOLETE @c emphasize that this is the name as seen by DOS (since I think DOS is | |
11962 | @c OBSOLETE @c single-minded about case of letters). ---doc@cygnus.com, 25feb91 | |
11963 | @c OBSOLETE @end example | |
11964 | @c OBSOLETE | |
11965 | @c OBSOLETE @noindent | |
11966 | @c OBSOLETE In this example, we've assumed your program is in a file called | |
11967 | @c OBSOLETE @file{myfoo}. Note that the filename given as the last argument to | |
11968 | @c OBSOLETE @code{target amd-eb} should be the name of the program as it appears to DOS. | |
11969 | @c OBSOLETE In our example this is simply @code{MYFOO}, but in general it can include | |
11970 | @c OBSOLETE a DOS path, and depending on your transfer mechanism may not resemble | |
11971 | @c OBSOLETE the name on the Unix side. | |
11972 | @c OBSOLETE | |
11973 | @c OBSOLETE At this point, you can set any breakpoints you wish; when you are ready | |
11974 | @c OBSOLETE to see your program run on the 29K board, use the @value{GDBN} command | |
11975 | @c OBSOLETE @code{run}. | |
11976 | @c OBSOLETE | |
11977 | @c OBSOLETE To stop debugging the remote program, use the @value{GDBN} @code{detach} | |
11978 | @c OBSOLETE command. | |
11979 | @c OBSOLETE | |
11980 | @c OBSOLETE To return control of the PC to its console, use @code{tip} or @code{cu} | |
11981 | @c OBSOLETE once again, after your @value{GDBN} session has concluded, to attach to | |
11982 | @c OBSOLETE @code{EBMON}. You can then type the command @code{q} to shut down | |
11983 | @c OBSOLETE @code{EBMON}, returning control to the DOS command-line interpreter. | |
11984 | @c OBSOLETE Type @kbd{CTTY con} to return command input to the main DOS console, | |
11985 | @c OBSOLETE and type @kbd{~.} to leave @code{tip} or @code{cu}. | |
11986 | @c OBSOLETE | |
11987 | @c OBSOLETE @node Remote Log | |
11988 | @c OBSOLETE @subsubsection Remote log | |
11989 | @c OBSOLETE @cindex @file{eb.log}, a log file for EB29K | |
11990 | @c OBSOLETE @cindex log file for EB29K | |
11991 | @c OBSOLETE | |
11992 | @c OBSOLETE The @code{target amd-eb} command creates a file @file{eb.log} in the | |
11993 | @c OBSOLETE current working directory, to help debug problems with the connection. | |
11994 | @c OBSOLETE @file{eb.log} records all the output from @code{EBMON}, including echoes | |
11995 | @c OBSOLETE of the commands sent to it. Running @samp{tail -f} on this file in | |
11996 | @c OBSOLETE another window often helps to understand trouble with @code{EBMON}, or | |
11997 | @c OBSOLETE unexpected events on the PC side of the connection. | |
104c1213 | 11998 | |
6d2ebf8b | 11999 | @node ARM |
104c1213 JM |
12000 | @subsection ARM |
12001 | ||
12002 | @table @code | |
12003 | ||
12004 | @kindex target rdi | |
12005 | @item target rdi @var{dev} | |
12006 | ARM Angel monitor, via RDI library interface to ADP protocol. You may | |
12007 | use this target to communicate with both boards running the Angel | |
12008 | monitor, or with the EmbeddedICE JTAG debug device. | |
5d161b24 | 12009 | |
104c1213 JM |
12010 | @kindex target rdp |
12011 | @item target rdp @var{dev} | |
12012 | ARM Demon monitor. | |
12013 | ||
12014 | @end table | |
12015 | ||
6d2ebf8b | 12016 | @node H8/300 |
104c1213 JM |
12017 | @subsection Hitachi H8/300 |
12018 | ||
12019 | @table @code | |
12020 | ||
d4f3574e | 12021 | @kindex target hms@r{, with H8/300} |
104c1213 JM |
12022 | @item target hms @var{dev} |
12023 | A Hitachi SH, H8/300, or H8/500 board, attached via serial line to your host. | |
12024 | Use special commands @code{device} and @code{speed} to control the serial | |
12025 | line and the communications speed used. | |
12026 | ||
d4f3574e | 12027 | @kindex target e7000@r{, with H8/300} |
104c1213 JM |
12028 | @item target e7000 @var{dev} |
12029 | E7000 emulator for Hitachi H8 and SH. | |
12030 | ||
d4f3574e SS |
12031 | @kindex target sh3@r{, with H8/300} |
12032 | @kindex target sh3e@r{, with H8/300} | |
104c1213 | 12033 | @item target sh3 @var{dev} |
96a2c332 | 12034 | @itemx target sh3e @var{dev} |
104c1213 JM |
12035 | Hitachi SH-3 and SH-3E target systems. |
12036 | ||
12037 | @end table | |
12038 | ||
12039 | @cindex download to H8/300 or H8/500 | |
12040 | @cindex H8/300 or H8/500 download | |
12041 | @cindex download to Hitachi SH | |
12042 | @cindex Hitachi SH download | |
12043 | When you select remote debugging to a Hitachi SH, H8/300, or H8/500 | |
12044 | board, the @code{load} command downloads your program to the Hitachi | |
12045 | board and also opens it as the current executable target for | |
12046 | @value{GDBN} on your host (like the @code{file} command). | |
12047 | ||
12048 | @value{GDBN} needs to know these things to talk to your | |
5d161b24 | 12049 | Hitachi SH, H8/300, or H8/500: |
104c1213 JM |
12050 | |
12051 | @enumerate | |
12052 | @item | |
12053 | that you want to use @samp{target hms}, the remote debugging interface | |
12054 | for Hitachi microprocessors, or @samp{target e7000}, the in-circuit | |
12055 | emulator for the Hitachi SH and the Hitachi 300H. (@samp{target hms} is | |
2df3850c | 12056 | the default when @value{GDBN} is configured specifically for the Hitachi SH, |
104c1213 JM |
12057 | H8/300, or H8/500.) |
12058 | ||
12059 | @item | |
12060 | what serial device connects your host to your Hitachi board (the first | |
12061 | serial device available on your host is the default). | |
12062 | ||
12063 | @item | |
12064 | what speed to use over the serial device. | |
12065 | @end enumerate | |
12066 | ||
12067 | @menu | |
12068 | * Hitachi Boards:: Connecting to Hitachi boards. | |
12069 | * Hitachi ICE:: Using the E7000 In-Circuit Emulator. | |
12070 | * Hitachi Special:: Special @value{GDBN} commands for Hitachi micros. | |
12071 | @end menu | |
12072 | ||
6d2ebf8b | 12073 | @node Hitachi Boards |
104c1213 JM |
12074 | @subsubsection Connecting to Hitachi boards |
12075 | ||
12076 | @c only for Unix hosts | |
12077 | @kindex device | |
12078 | @cindex serial device, Hitachi micros | |
96a2c332 | 12079 | Use the special @code{@value{GDBN}} command @samp{device @var{port}} if you |
104c1213 JM |
12080 | need to explicitly set the serial device. The default @var{port} is the |
12081 | first available port on your host. This is only necessary on Unix | |
12082 | hosts, where it is typically something like @file{/dev/ttya}. | |
12083 | ||
12084 | @kindex speed | |
12085 | @cindex serial line speed, Hitachi micros | |
96a2c332 | 12086 | @code{@value{GDBN}} has another special command to set the communications |
104c1213 | 12087 | speed: @samp{speed @var{bps}}. This command also is only used from Unix |
2df3850c | 12088 | hosts; on DOS hosts, set the line speed as usual from outside @value{GDBN} with |
d4f3574e SS |
12089 | the DOS @code{mode} command (for instance, |
12090 | @w{@kbd{mode com2:9600,n,8,1,p}} for a 9600@dmn{bps} connection). | |
104c1213 JM |
12091 | |
12092 | The @samp{device} and @samp{speed} commands are available only when you | |
12093 | use a Unix host to debug your Hitachi microprocessor programs. If you | |
12094 | use a DOS host, | |
12095 | @value{GDBN} depends on an auxiliary terminate-and-stay-resident program | |
12096 | called @code{asynctsr} to communicate with the development board | |
12097 | through a PC serial port. You must also use the DOS @code{mode} command | |
12098 | to set up the serial port on the DOS side. | |
12099 | ||
12100 | The following sample session illustrates the steps needed to start a | |
12101 | program under @value{GDBN} control on an H8/300. The example uses a | |
12102 | sample H8/300 program called @file{t.x}. The procedure is the same for | |
12103 | the Hitachi SH and the H8/500. | |
12104 | ||
12105 | First hook up your development board. In this example, we use a | |
12106 | board attached to serial port @code{COM2}; if you use a different serial | |
12107 | port, substitute its name in the argument of the @code{mode} command. | |
12108 | When you call @code{asynctsr}, the auxiliary comms program used by the | |
d4f3574e | 12109 | debugger, you give it just the numeric part of the serial port's name; |
104c1213 JM |
12110 | for example, @samp{asyncstr 2} below runs @code{asyncstr} on |
12111 | @code{COM2}. | |
12112 | ||
12113 | @example | |
12114 | C:\H8300\TEST> asynctsr 2 | |
12115 | C:\H8300\TEST> mode com2:9600,n,8,1,p | |
12116 | ||
12117 | Resident portion of MODE loaded | |
12118 | ||
12119 | COM2: 9600, n, 8, 1, p | |
12120 | ||
12121 | @end example | |
12122 | ||
12123 | @quotation | |
12124 | @emph{Warning:} We have noticed a bug in PC-NFS that conflicts with | |
12125 | @code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to | |
12126 | disable it, or even boot without it, to use @code{asynctsr} to control | |
12127 | your development board. | |
12128 | @end quotation | |
12129 | ||
d4f3574e | 12130 | @kindex target hms@r{, and serial protocol} |
104c1213 JM |
12131 | Now that serial communications are set up, and the development board is |
12132 | connected, you can start up @value{GDBN}. Call @code{@value{GDBP}} with | |
96a2c332 | 12133 | the name of your program as the argument. @code{@value{GDBN}} prompts |
104c1213 JM |
12134 | you, as usual, with the prompt @samp{(@value{GDBP})}. Use two special |
12135 | commands to begin your debugging session: @samp{target hms} to specify | |
12136 | cross-debugging to the Hitachi board, and the @code{load} command to | |
12137 | download your program to the board. @code{load} displays the names of | |
12138 | the program's sections, and a @samp{*} for each 2K of data downloaded. | |
12139 | (If you want to refresh @value{GDBN} data on symbols or on the | |
12140 | executable file without downloading, use the @value{GDBN} commands | |
12141 | @code{file} or @code{symbol-file}. These commands, and @code{load} | |
12142 | itself, are described in @ref{Files,,Commands to specify files}.) | |
12143 | ||
12144 | @smallexample | |
12145 | (eg-C:\H8300\TEST) @value{GDBP} t.x | |
2df3850c | 12146 | @value{GDBN} is free software and you are welcome to distribute copies |
5d161b24 | 12147 | of it under certain conditions; type "show copying" to see |
104c1213 | 12148 | the conditions. |
5d161b24 | 12149 | There is absolutely no warranty for @value{GDBN}; type "show warranty" |
104c1213 | 12150 | for details. |
2df3850c JM |
12151 | @value{GDBN} @value{GDBVN}, Copyright 1992 Free Software Foundation, Inc... |
12152 | (@value{GDBP}) target hms | |
104c1213 | 12153 | Connected to remote H8/300 HMS system. |
2df3850c | 12154 | (@value{GDBP}) load t.x |
104c1213 JM |
12155 | .text : 0x8000 .. 0xabde *********** |
12156 | .data : 0xabde .. 0xad30 * | |
12157 | .stack : 0xf000 .. 0xf014 * | |
12158 | @end smallexample | |
12159 | ||
12160 | At this point, you're ready to run or debug your program. From here on, | |
12161 | you can use all the usual @value{GDBN} commands. The @code{break} command | |
12162 | sets breakpoints; the @code{run} command starts your program; | |
12163 | @code{print} or @code{x} display data; the @code{continue} command | |
12164 | resumes execution after stopping at a breakpoint. You can use the | |
12165 | @code{help} command at any time to find out more about @value{GDBN} commands. | |
12166 | ||
12167 | Remember, however, that @emph{operating system} facilities aren't | |
12168 | available on your development board; for example, if your program hangs, | |
12169 | you can't send an interrupt---but you can press the @sc{reset} switch! | |
12170 | ||
12171 | Use the @sc{reset} button on the development board | |
12172 | @itemize @bullet | |
12173 | @item | |
12174 | to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has | |
12175 | no way to pass an interrupt signal to the development board); and | |
12176 | ||
12177 | @item | |
12178 | to return to the @value{GDBN} command prompt after your program finishes | |
12179 | normally. The communications protocol provides no other way for @value{GDBN} | |
12180 | to detect program completion. | |
12181 | @end itemize | |
12182 | ||
12183 | In either case, @value{GDBN} sees the effect of a @sc{reset} on the | |
12184 | development board as a ``normal exit'' of your program. | |
12185 | ||
6d2ebf8b | 12186 | @node Hitachi ICE |
104c1213 JM |
12187 | @subsubsection Using the E7000 in-circuit emulator |
12188 | ||
d4f3574e | 12189 | @kindex target e7000@r{, with Hitachi ICE} |
104c1213 JM |
12190 | You can use the E7000 in-circuit emulator to develop code for either the |
12191 | Hitachi SH or the H8/300H. Use one of these forms of the @samp{target | |
12192 | e7000} command to connect @value{GDBN} to your E7000: | |
12193 | ||
12194 | @table @code | |
12195 | @item target e7000 @var{port} @var{speed} | |
12196 | Use this form if your E7000 is connected to a serial port. The | |
12197 | @var{port} argument identifies what serial port to use (for example, | |
12198 | @samp{com2}). The third argument is the line speed in bits per second | |
12199 | (for example, @samp{9600}). | |
12200 | ||
12201 | @item target e7000 @var{hostname} | |
12202 | If your E7000 is installed as a host on a TCP/IP network, you can just | |
12203 | specify its hostname; @value{GDBN} uses @code{telnet} to connect. | |
12204 | @end table | |
12205 | ||
6d2ebf8b | 12206 | @node Hitachi Special |
104c1213 JM |
12207 | @subsubsection Special @value{GDBN} commands for Hitachi micros |
12208 | ||
12209 | Some @value{GDBN} commands are available only for the H8/300: | |
12210 | ||
12211 | @table @code | |
12212 | ||
12213 | @kindex set machine | |
12214 | @kindex show machine | |
12215 | @item set machine h8300 | |
12216 | @itemx set machine h8300h | |
12217 | Condition @value{GDBN} for one of the two variants of the H8/300 | |
12218 | architecture with @samp{set machine}. You can use @samp{show machine} | |
12219 | to check which variant is currently in effect. | |
12220 | ||
12221 | @end table | |
12222 | ||
6d2ebf8b | 12223 | @node H8/500 |
104c1213 JM |
12224 | @subsection H8/500 |
12225 | ||
12226 | @table @code | |
12227 | ||
12228 | @kindex set memory @var{mod} | |
12229 | @cindex memory models, H8/500 | |
12230 | @item set memory @var{mod} | |
12231 | @itemx show memory | |
12232 | Specify which H8/500 memory model (@var{mod}) you are using with | |
12233 | @samp{set memory}; check which memory model is in effect with @samp{show | |
12234 | memory}. The accepted values for @var{mod} are @code{small}, | |
12235 | @code{big}, @code{medium}, and @code{compact}. | |
12236 | ||
12237 | @end table | |
12238 | ||
6d2ebf8b | 12239 | @node i960 |
104c1213 JM |
12240 | @subsection Intel i960 |
12241 | ||
12242 | @table @code | |
12243 | ||
12244 | @kindex target mon960 | |
12245 | @item target mon960 @var{dev} | |
12246 | MON960 monitor for Intel i960. | |
12247 | ||
f0ca3dce | 12248 | @kindex target nindy |
104c1213 JM |
12249 | @item target nindy @var{devicename} |
12250 | An Intel 960 board controlled by a Nindy Monitor. @var{devicename} is | |
12251 | the name of the serial device to use for the connection, e.g. | |
12252 | @file{/dev/ttya}. | |
12253 | ||
12254 | @end table | |
12255 | ||
12256 | @cindex Nindy | |
12257 | @cindex i960 | |
12258 | @dfn{Nindy} is a ROM Monitor program for Intel 960 target systems. When | |
12259 | @value{GDBN} is configured to control a remote Intel 960 using Nindy, you can | |
12260 | tell @value{GDBN} how to connect to the 960 in several ways: | |
12261 | ||
12262 | @itemize @bullet | |
12263 | @item | |
12264 | Through command line options specifying serial port, version of the | |
12265 | Nindy protocol, and communications speed; | |
12266 | ||
12267 | @item | |
12268 | By responding to a prompt on startup; | |
12269 | ||
12270 | @item | |
12271 | By using the @code{target} command at any point during your @value{GDBN} | |
12272 | session. @xref{Target Commands, ,Commands for managing targets}. | |
12273 | ||
104c1213 JM |
12274 | @end itemize |
12275 | ||
12276 | @cindex download to Nindy-960 | |
12277 | With the Nindy interface to an Intel 960 board, @code{load} | |
12278 | downloads @var{filename} to the 960 as well as adding its symbols in | |
12279 | @value{GDBN}. | |
12280 | ||
12281 | @menu | |
12282 | * Nindy Startup:: Startup with Nindy | |
12283 | * Nindy Options:: Options for Nindy | |
12284 | * Nindy Reset:: Nindy reset command | |
12285 | @end menu | |
12286 | ||
6d2ebf8b | 12287 | @node Nindy Startup |
104c1213 JM |
12288 | @subsubsection Startup with Nindy |
12289 | ||
12290 | If you simply start @code{@value{GDBP}} without using any command-line | |
12291 | options, you are prompted for what serial port to use, @emph{before} you | |
12292 | reach the ordinary @value{GDBN} prompt: | |
12293 | ||
12294 | @example | |
5d161b24 | 12295 | Attach /dev/ttyNN -- specify NN, or "quit" to quit: |
104c1213 JM |
12296 | @end example |
12297 | ||
12298 | @noindent | |
12299 | Respond to the prompt with whatever suffix (after @samp{/dev/tty}) | |
12300 | identifies the serial port you want to use. You can, if you choose, | |
12301 | simply start up with no Nindy connection by responding to the prompt | |
12302 | with an empty line. If you do this and later wish to attach to Nindy, | |
12303 | use @code{target} (@pxref{Target Commands, ,Commands for managing targets}). | |
12304 | ||
6d2ebf8b | 12305 | @node Nindy Options |
104c1213 JM |
12306 | @subsubsection Options for Nindy |
12307 | ||
12308 | These are the startup options for beginning your @value{GDBN} session with a | |
12309 | Nindy-960 board attached: | |
12310 | ||
12311 | @table @code | |
12312 | @item -r @var{port} | |
12313 | Specify the serial port name of a serial interface to be used to connect | |
12314 | to the target system. This option is only available when @value{GDBN} is | |
12315 | configured for the Intel 960 target architecture. You may specify | |
12316 | @var{port} as any of: a full pathname (e.g. @samp{-r /dev/ttya}), a | |
12317 | device name in @file{/dev} (e.g. @samp{-r ttya}), or simply the unique | |
12318 | suffix for a specific @code{tty} (e.g. @samp{-r a}). | |
12319 | ||
12320 | @item -O | |
12321 | (An uppercase letter ``O'', not a zero.) Specify that @value{GDBN} should use | |
12322 | the ``old'' Nindy monitor protocol to connect to the target system. | |
12323 | This option is only available when @value{GDBN} is configured for the Intel 960 | |
12324 | target architecture. | |
12325 | ||
12326 | @quotation | |
12327 | @emph{Warning:} if you specify @samp{-O}, but are actually trying to | |
12328 | connect to a target system that expects the newer protocol, the connection | |
12329 | fails, appearing to be a speed mismatch. @value{GDBN} repeatedly | |
12330 | attempts to reconnect at several different line speeds. You can abort | |
12331 | this process with an interrupt. | |
12332 | @end quotation | |
12333 | ||
12334 | @item -brk | |
12335 | Specify that @value{GDBN} should first send a @code{BREAK} signal to the target | |
12336 | system, in an attempt to reset it, before connecting to a Nindy target. | |
12337 | ||
12338 | @quotation | |
12339 | @emph{Warning:} Many target systems do not have the hardware that this | |
12340 | requires; it only works with a few boards. | |
12341 | @end quotation | |
12342 | @end table | |
12343 | ||
12344 | The standard @samp{-b} option controls the line speed used on the serial | |
12345 | port. | |
12346 | ||
12347 | @c @group | |
6d2ebf8b | 12348 | @node Nindy Reset |
104c1213 JM |
12349 | @subsubsection Nindy reset command |
12350 | ||
12351 | @table @code | |
12352 | @item reset | |
12353 | @kindex reset | |
12354 | For a Nindy target, this command sends a ``break'' to the remote target | |
12355 | system; this is only useful if the target has been equipped with a | |
12356 | circuit to perform a hard reset (or some other interesting action) when | |
12357 | a break is detected. | |
12358 | @end table | |
12359 | @c @end group | |
12360 | ||
6d2ebf8b | 12361 | @node M32R/D |
104c1213 JM |
12362 | @subsection Mitsubishi M32R/D |
12363 | ||
12364 | @table @code | |
12365 | ||
12366 | @kindex target m32r | |
12367 | @item target m32r @var{dev} | |
12368 | Mitsubishi M32R/D ROM monitor. | |
12369 | ||
12370 | @end table | |
12371 | ||
6d2ebf8b | 12372 | @node M68K |
104c1213 JM |
12373 | @subsection M68k |
12374 | ||
12375 | The Motorola m68k configuration includes ColdFire support, and | |
12376 | target command for the following ROM monitors. | |
12377 | ||
12378 | @table @code | |
12379 | ||
12380 | @kindex target abug | |
12381 | @item target abug @var{dev} | |
12382 | ABug ROM monitor for M68K. | |
12383 | ||
12384 | @kindex target cpu32bug | |
12385 | @item target cpu32bug @var{dev} | |
12386 | CPU32BUG monitor, running on a CPU32 (M68K) board. | |
12387 | ||
12388 | @kindex target dbug | |
12389 | @item target dbug @var{dev} | |
12390 | dBUG ROM monitor for Motorola ColdFire. | |
12391 | ||
12392 | @kindex target est | |
12393 | @item target est @var{dev} | |
12394 | EST-300 ICE monitor, running on a CPU32 (M68K) board. | |
12395 | ||
12396 | @kindex target rom68k | |
12397 | @item target rom68k @var{dev} | |
12398 | ROM 68K monitor, running on an M68K IDP board. | |
12399 | ||
12400 | @end table | |
12401 | ||
12402 | If @value{GDBN} is configured with @code{m68*-ericsson-*}, it will | |
12403 | instead have only a single special target command: | |
12404 | ||
12405 | @table @code | |
12406 | ||
12407 | @kindex target es1800 | |
12408 | @item target es1800 @var{dev} | |
12409 | ES-1800 emulator for M68K. | |
12410 | ||
12411 | @end table | |
12412 | ||
12413 | [context?] | |
12414 | ||
12415 | @table @code | |
12416 | ||
12417 | @kindex target rombug | |
12418 | @item target rombug @var{dev} | |
12419 | ROMBUG ROM monitor for OS/9000. | |
12420 | ||
12421 | @end table | |
12422 | ||
6d2ebf8b | 12423 | @node M88K |
104c1213 JM |
12424 | @subsection M88K |
12425 | ||
12426 | @table @code | |
12427 | ||
12428 | @kindex target bug | |
12429 | @item target bug @var{dev} | |
12430 | BUG monitor, running on a MVME187 (m88k) board. | |
12431 | ||
12432 | @end table | |
12433 | ||
6d2ebf8b | 12434 | @node MIPS Embedded |
104c1213 JM |
12435 | @subsection MIPS Embedded |
12436 | ||
12437 | @cindex MIPS boards | |
12438 | @value{GDBN} can use the MIPS remote debugging protocol to talk to a | |
12439 | MIPS board attached to a serial line. This is available when | |
12440 | you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}. | |
12441 | ||
12442 | @need 1000 | |
12443 | Use these @value{GDBN} commands to specify the connection to your target board: | |
12444 | ||
12445 | @table @code | |
12446 | @item target mips @var{port} | |
12447 | @kindex target mips @var{port} | |
12448 | To run a program on the board, start up @code{@value{GDBP}} with the | |
12449 | name of your program as the argument. To connect to the board, use the | |
12450 | command @samp{target mips @var{port}}, where @var{port} is the name of | |
12451 | the serial port connected to the board. If the program has not already | |
12452 | been downloaded to the board, you may use the @code{load} command to | |
12453 | download it. You can then use all the usual @value{GDBN} commands. | |
12454 | ||
12455 | For example, this sequence connects to the target board through a serial | |
12456 | port, and loads and runs a program called @var{prog} through the | |
12457 | debugger: | |
12458 | ||
12459 | @example | |
12460 | host$ @value{GDBP} @var{prog} | |
2df3850c JM |
12461 | @value{GDBN} is free software and @dots{} |
12462 | (@value{GDBP}) target mips /dev/ttyb | |
12463 | (@value{GDBP}) load @var{prog} | |
12464 | (@value{GDBP}) run | |
104c1213 JM |
12465 | @end example |
12466 | ||
12467 | @item target mips @var{hostname}:@var{portnumber} | |
12468 | On some @value{GDBN} host configurations, you can specify a TCP | |
12469 | connection (for instance, to a serial line managed by a terminal | |
12470 | concentrator) instead of a serial port, using the syntax | |
12471 | @samp{@var{hostname}:@var{portnumber}}. | |
12472 | ||
12473 | @item target pmon @var{port} | |
12474 | @kindex target pmon @var{port} | |
12475 | PMON ROM monitor. | |
12476 | ||
12477 | @item target ddb @var{port} | |
12478 | @kindex target ddb @var{port} | |
12479 | NEC's DDB variant of PMON for Vr4300. | |
12480 | ||
12481 | @item target lsi @var{port} | |
12482 | @kindex target lsi @var{port} | |
12483 | LSI variant of PMON. | |
12484 | ||
12485 | @kindex target r3900 | |
12486 | @item target r3900 @var{dev} | |
12487 | Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips. | |
12488 | ||
12489 | @kindex target array | |
12490 | @item target array @var{dev} | |
12491 | Array Tech LSI33K RAID controller board. | |
12492 | ||
12493 | @end table | |
12494 | ||
12495 | ||
12496 | @noindent | |
12497 | @value{GDBN} also supports these special commands for MIPS targets: | |
12498 | ||
12499 | @table @code | |
12500 | @item set processor @var{args} | |
12501 | @itemx show processor | |
12502 | @kindex set processor @var{args} | |
12503 | @kindex show processor | |
12504 | Use the @code{set processor} command to set the type of MIPS | |
12505 | processor when you want to access processor-type-specific registers. | |
5d161b24 | 12506 | For example, @code{set processor @var{r3041}} tells @value{GDBN} |
96c405b3 | 12507 | to use the CPU registers appropriate for the 3041 chip. |
5d161b24 | 12508 | Use the @code{show processor} command to see what MIPS processor @value{GDBN} |
104c1213 | 12509 | is using. Use the @code{info reg} command to see what registers |
5d161b24 | 12510 | @value{GDBN} is using. |
104c1213 JM |
12511 | |
12512 | @item set mipsfpu double | |
12513 | @itemx set mipsfpu single | |
12514 | @itemx set mipsfpu none | |
12515 | @itemx show mipsfpu | |
12516 | @kindex set mipsfpu | |
12517 | @kindex show mipsfpu | |
12518 | @cindex MIPS remote floating point | |
12519 | @cindex floating point, MIPS remote | |
12520 | If your target board does not support the MIPS floating point | |
12521 | coprocessor, you should use the command @samp{set mipsfpu none} (if you | |
96a2c332 | 12522 | need this, you may wish to put the command in your @value{GDBN} init |
104c1213 JM |
12523 | file). This tells @value{GDBN} how to find the return value of |
12524 | functions which return floating point values. It also allows | |
12525 | @value{GDBN} to avoid saving the floating point registers when calling | |
12526 | functions on the board. If you are using a floating point coprocessor | |
12527 | with only single precision floating point support, as on the @sc{r4650} | |
12528 | processor, use the command @samp{set mipsfpu single}. The default | |
12529 | double precision floating point coprocessor may be selected using | |
12530 | @samp{set mipsfpu double}. | |
12531 | ||
12532 | In previous versions the only choices were double precision or no | |
12533 | floating point, so @samp{set mipsfpu on} will select double precision | |
12534 | and @samp{set mipsfpu off} will select no floating point. | |
12535 | ||
12536 | As usual, you can inquire about the @code{mipsfpu} variable with | |
12537 | @samp{show mipsfpu}. | |
12538 | ||
12539 | @item set remotedebug @var{n} | |
12540 | @itemx show remotedebug | |
d4f3574e SS |
12541 | @kindex set remotedebug@r{, MIPS protocol} |
12542 | @kindex show remotedebug@r{, MIPS protocol} | |
104c1213 JM |
12543 | @cindex @code{remotedebug}, MIPS protocol |
12544 | @cindex MIPS @code{remotedebug} protocol | |
12545 | @c FIXME! For this to be useful, you must know something about the MIPS | |
12546 | @c FIXME...protocol. Where is it described? | |
12547 | You can see some debugging information about communications with the board | |
12548 | by setting the @code{remotedebug} variable. If you set it to @code{1} using | |
12549 | @samp{set remotedebug 1}, every packet is displayed. If you set it | |
12550 | to @code{2}, every character is displayed. You can check the current value | |
12551 | at any time with the command @samp{show remotedebug}. | |
12552 | ||
12553 | @item set timeout @var{seconds} | |
12554 | @itemx set retransmit-timeout @var{seconds} | |
12555 | @itemx show timeout | |
12556 | @itemx show retransmit-timeout | |
12557 | @cindex @code{timeout}, MIPS protocol | |
12558 | @cindex @code{retransmit-timeout}, MIPS protocol | |
12559 | @kindex set timeout | |
12560 | @kindex show timeout | |
12561 | @kindex set retransmit-timeout | |
12562 | @kindex show retransmit-timeout | |
12563 | You can control the timeout used while waiting for a packet, in the MIPS | |
12564 | remote protocol, with the @code{set timeout @var{seconds}} command. The | |
12565 | default is 5 seconds. Similarly, you can control the timeout used while | |
12566 | waiting for an acknowledgement of a packet with the @code{set | |
12567 | retransmit-timeout @var{seconds}} command. The default is 3 seconds. | |
12568 | You can inspect both values with @code{show timeout} and @code{show | |
12569 | retransmit-timeout}. (These commands are @emph{only} available when | |
12570 | @value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.) | |
12571 | ||
12572 | The timeout set by @code{set timeout} does not apply when @value{GDBN} | |
12573 | is waiting for your program to stop. In that case, @value{GDBN} waits | |
12574 | forever because it has no way of knowing how long the program is going | |
12575 | to run before stopping. | |
12576 | @end table | |
12577 | ||
6d2ebf8b | 12578 | @node PowerPC |
104c1213 JM |
12579 | @subsection PowerPC |
12580 | ||
12581 | @table @code | |
12582 | ||
12583 | @kindex target dink32 | |
12584 | @item target dink32 @var{dev} | |
12585 | DINK32 ROM monitor. | |
12586 | ||
12587 | @kindex target ppcbug | |
12588 | @item target ppcbug @var{dev} | |
12589 | @kindex target ppcbug1 | |
12590 | @item target ppcbug1 @var{dev} | |
12591 | PPCBUG ROM monitor for PowerPC. | |
12592 | ||
12593 | @kindex target sds | |
12594 | @item target sds @var{dev} | |
12595 | SDS monitor, running on a PowerPC board (such as Motorola's ADS). | |
12596 | ||
12597 | @end table | |
12598 | ||
6d2ebf8b | 12599 | @node PA |
104c1213 JM |
12600 | @subsection HP PA Embedded |
12601 | ||
12602 | @table @code | |
12603 | ||
12604 | @kindex target op50n | |
12605 | @item target op50n @var{dev} | |
12606 | OP50N monitor, running on an OKI HPPA board. | |
12607 | ||
12608 | @kindex target w89k | |
12609 | @item target w89k @var{dev} | |
12610 | W89K monitor, running on a Winbond HPPA board. | |
12611 | ||
12612 | @end table | |
12613 | ||
6d2ebf8b | 12614 | @node SH |
104c1213 JM |
12615 | @subsection Hitachi SH |
12616 | ||
12617 | @table @code | |
12618 | ||
d4f3574e | 12619 | @kindex target hms@r{, with Hitachi SH} |
104c1213 JM |
12620 | @item target hms @var{dev} |
12621 | A Hitachi SH board attached via serial line to your host. Use special | |
12622 | commands @code{device} and @code{speed} to control the serial line and | |
12623 | the communications speed used. | |
12624 | ||
d4f3574e | 12625 | @kindex target e7000@r{, with Hitachi SH} |
104c1213 JM |
12626 | @item target e7000 @var{dev} |
12627 | E7000 emulator for Hitachi SH. | |
12628 | ||
d4f3574e SS |
12629 | @kindex target sh3@r{, with SH} |
12630 | @kindex target sh3e@r{, with SH} | |
104c1213 JM |
12631 | @item target sh3 @var{dev} |
12632 | @item target sh3e @var{dev} | |
12633 | Hitachi SH-3 and SH-3E target systems. | |
12634 | ||
12635 | @end table | |
12636 | ||
6d2ebf8b | 12637 | @node Sparclet |
104c1213 JM |
12638 | @subsection Tsqware Sparclet |
12639 | ||
12640 | @cindex Sparclet | |
12641 | ||
5d161b24 DB |
12642 | @value{GDBN} enables developers to debug tasks running on |
12643 | Sparclet targets from a Unix host. | |
104c1213 JM |
12644 | @value{GDBN} uses code that runs on |
12645 | both the Unix host and on the Sparclet target. The program | |
5d161b24 | 12646 | @code{@value{GDBP}} is installed and executed on the Unix host. |
104c1213 JM |
12647 | |
12648 | @table @code | |
f0ca3dce | 12649 | @item remotetimeout @var{args} |
104c1213 | 12650 | @kindex remotetimeout |
5d161b24 DB |
12651 | @value{GDBN} supports the option @code{remotetimeout}. |
12652 | This option is set by the user, and @var{args} represents the number of | |
12653 | seconds @value{GDBN} waits for responses. | |
104c1213 JM |
12654 | @end table |
12655 | ||
41afff9a | 12656 | @cindex compiling, on Sparclet |
5d161b24 | 12657 | When compiling for debugging, include the options @samp{-g} to get debug |
d4f3574e | 12658 | information and @samp{-Ttext} to relocate the program to where you wish to |
5d161b24 | 12659 | load it on the target. You may also want to add the options @samp{-n} or |
d4f3574e | 12660 | @samp{-N} in order to reduce the size of the sections. Example: |
104c1213 JM |
12661 | |
12662 | @example | |
12663 | sparclet-aout-gcc prog.c -Ttext 0x12010000 -g -o prog -N | |
12664 | @end example | |
12665 | ||
d4f3574e | 12666 | You can use @code{objdump} to verify that the addresses are what you intended: |
104c1213 JM |
12667 | |
12668 | @example | |
12669 | sparclet-aout-objdump --headers --syms prog | |
12670 | @end example | |
12671 | ||
41afff9a | 12672 | @cindex running, on Sparclet |
104c1213 JM |
12673 | Once you have set |
12674 | your Unix execution search path to find @value{GDBN}, you are ready to | |
5d161b24 | 12675 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} |
104c1213 JM |
12676 | (or @code{sparclet-aout-gdb}, depending on your installation). |
12677 | ||
12678 | @value{GDBN} comes up showing the prompt: | |
12679 | ||
12680 | @example | |
12681 | (gdbslet) | |
12682 | @end example | |
12683 | ||
12684 | @menu | |
12685 | * Sparclet File:: Setting the file to debug | |
12686 | * Sparclet Connection:: Connecting to Sparclet | |
12687 | * Sparclet Download:: Sparclet download | |
5d161b24 | 12688 | * Sparclet Execution:: Running and debugging |
104c1213 JM |
12689 | @end menu |
12690 | ||
6d2ebf8b | 12691 | @node Sparclet File |
104c1213 JM |
12692 | @subsubsection Setting file to debug |
12693 | ||
12694 | The @value{GDBN} command @code{file} lets you choose with program to debug. | |
12695 | ||
12696 | @example | |
12697 | (gdbslet) file prog | |
12698 | @end example | |
12699 | ||
12700 | @need 1000 | |
12701 | @value{GDBN} then attempts to read the symbol table of @file{prog}. | |
12702 | @value{GDBN} locates | |
12703 | the file by searching the directories listed in the command search | |
12704 | path. | |
12705 | If the file was compiled with debug information (option "-g"), source | |
12706 | files will be searched as well. | |
12707 | @value{GDBN} locates | |
12708 | the source files by searching the directories listed in the directory search | |
12709 | path (@pxref{Environment, ,Your program's environment}). | |
12710 | If it fails | |
12711 | to find a file, it displays a message such as: | |
12712 | ||
12713 | @example | |
12714 | prog: No such file or directory. | |
12715 | @end example | |
12716 | ||
12717 | When this happens, add the appropriate directories to the search paths with | |
5d161b24 | 12718 | the @value{GDBN} commands @code{path} and @code{dir}, and execute the |
104c1213 JM |
12719 | @code{target} command again. |
12720 | ||
6d2ebf8b | 12721 | @node Sparclet Connection |
104c1213 JM |
12722 | @subsubsection Connecting to Sparclet |
12723 | ||
12724 | The @value{GDBN} command @code{target} lets you connect to a Sparclet target. | |
12725 | To connect to a target on serial port ``@code{ttya}'', type: | |
12726 | ||
12727 | @example | |
12728 | (gdbslet) target sparclet /dev/ttya | |
12729 | Remote target sparclet connected to /dev/ttya | |
5d161b24 | 12730 | main () at ../prog.c:3 |
104c1213 JM |
12731 | @end example |
12732 | ||
12733 | @need 750 | |
12734 | @value{GDBN} displays messages like these: | |
12735 | ||
d4f3574e | 12736 | @example |
104c1213 | 12737 | Connected to ttya. |
d4f3574e | 12738 | @end example |
104c1213 | 12739 | |
6d2ebf8b | 12740 | @node Sparclet Download |
104c1213 JM |
12741 | @subsubsection Sparclet download |
12742 | ||
12743 | @cindex download to Sparclet | |
5d161b24 | 12744 | Once connected to the Sparclet target, |
104c1213 JM |
12745 | you can use the @value{GDBN} |
12746 | @code{load} command to download the file from the host to the target. | |
12747 | The file name and load offset should be given as arguments to the @code{load} | |
12748 | command. | |
5d161b24 | 12749 | Since the file format is aout, the program must be loaded to the starting |
d4f3574e | 12750 | address. You can use @code{objdump} to find out what this value is. The load |
104c1213 JM |
12751 | offset is an offset which is added to the VMA (virtual memory address) |
12752 | of each of the file's sections. | |
12753 | For instance, if the program | |
12754 | @file{prog} was linked to text address 0x1201000, with data at 0x12010160 | |
12755 | and bss at 0x12010170, in @value{GDBN}, type: | |
12756 | ||
12757 | @example | |
12758 | (gdbslet) load prog 0x12010000 | |
12759 | Loading section .text, size 0xdb0 vma 0x12010000 | |
12760 | @end example | |
12761 | ||
5d161b24 DB |
12762 | If the code is loaded at a different address then what the program was linked |
12763 | to, you may need to use the @code{section} and @code{add-symbol-file} commands | |
104c1213 JM |
12764 | to tell @value{GDBN} where to map the symbol table. |
12765 | ||
6d2ebf8b | 12766 | @node Sparclet Execution |
104c1213 JM |
12767 | @subsubsection Running and debugging |
12768 | ||
12769 | @cindex running and debugging Sparclet programs | |
12770 | You can now begin debugging the task using @value{GDBN}'s execution control | |
5d161b24 | 12771 | commands, @code{b}, @code{step}, @code{run}, etc. See the @value{GDBN} |
104c1213 JM |
12772 | manual for the list of commands. |
12773 | ||
12774 | @example | |
12775 | (gdbslet) b main | |
12776 | Breakpoint 1 at 0x12010000: file prog.c, line 3. | |
5d161b24 | 12777 | (gdbslet) run |
104c1213 JM |
12778 | Starting program: prog |
12779 | Breakpoint 1, main (argc=1, argv=0xeffff21c) at prog.c:3 | |
12780 | 3 char *symarg = 0; | |
12781 | (gdbslet) step | |
12782 | 4 char *execarg = "hello!"; | |
5d161b24 | 12783 | (gdbslet) |
104c1213 JM |
12784 | @end example |
12785 | ||
6d2ebf8b | 12786 | @node Sparclite |
104c1213 JM |
12787 | @subsection Fujitsu Sparclite |
12788 | ||
12789 | @table @code | |
12790 | ||
12791 | @kindex target sparclite | |
12792 | @item target sparclite @var{dev} | |
5d161b24 DB |
12793 | Fujitsu sparclite boards, used only for the purpose of loading. |
12794 | You must use an additional command to debug the program. | |
12795 | For example: target remote @var{dev} using @value{GDBN} standard | |
104c1213 JM |
12796 | remote protocol. |
12797 | ||
12798 | @end table | |
12799 | ||
6d2ebf8b | 12800 | @node ST2000 |
104c1213 JM |
12801 | @subsection Tandem ST2000 |
12802 | ||
2df3850c | 12803 | @value{GDBN} may be used with a Tandem ST2000 phone switch, running Tandem's |
104c1213 JM |
12804 | STDBUG protocol. |
12805 | ||
12806 | To connect your ST2000 to the host system, see the manufacturer's | |
12807 | manual. Once the ST2000 is physically attached, you can run: | |
12808 | ||
12809 | @example | |
12810 | target st2000 @var{dev} @var{speed} | |
12811 | @end example | |
12812 | ||
12813 | @noindent | |
12814 | to establish it as your debugging environment. @var{dev} is normally | |
12815 | the name of a serial device, such as @file{/dev/ttya}, connected to the | |
12816 | ST2000 via a serial line. You can instead specify @var{dev} as a TCP | |
12817 | connection (for example, to a serial line attached via a terminal | |
12818 | concentrator) using the syntax @code{@var{hostname}:@var{portnumber}}. | |
12819 | ||
12820 | The @code{load} and @code{attach} commands are @emph{not} defined for | |
12821 | this target; you must load your program into the ST2000 as you normally | |
12822 | would for standalone operation. @value{GDBN} reads debugging information | |
12823 | (such as symbols) from a separate, debugging version of the program | |
12824 | available on your host computer. | |
12825 | @c FIXME!! This is terribly vague; what little content is here is | |
12826 | @c basically hearsay. | |
12827 | ||
12828 | @cindex ST2000 auxiliary commands | |
12829 | These auxiliary @value{GDBN} commands are available to help you with the ST2000 | |
12830 | environment: | |
12831 | ||
12832 | @table @code | |
12833 | @item st2000 @var{command} | |
12834 | @kindex st2000 @var{cmd} | |
12835 | @cindex STDBUG commands (ST2000) | |
12836 | @cindex commands to STDBUG (ST2000) | |
12837 | Send a @var{command} to the STDBUG monitor. See the manufacturer's | |
12838 | manual for available commands. | |
12839 | ||
12840 | @item connect | |
12841 | @cindex connect (to STDBUG) | |
12842 | Connect the controlling terminal to the STDBUG command monitor. When | |
12843 | you are done interacting with STDBUG, typing either of two character | |
12844 | sequences gets you back to the @value{GDBN} command prompt: | |
12845 | @kbd{@key{RET}~.} (Return, followed by tilde and period) or | |
12846 | @kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D). | |
12847 | @end table | |
12848 | ||
6d2ebf8b | 12849 | @node Z8000 |
104c1213 JM |
12850 | @subsection Zilog Z8000 |
12851 | ||
12852 | @cindex Z8000 | |
12853 | @cindex simulator, Z8000 | |
12854 | @cindex Zilog Z8000 simulator | |
12855 | ||
12856 | When configured for debugging Zilog Z8000 targets, @value{GDBN} includes | |
12857 | a Z8000 simulator. | |
12858 | ||
12859 | For the Z8000 family, @samp{target sim} simulates either the Z8002 (the | |
12860 | unsegmented variant of the Z8000 architecture) or the Z8001 (the | |
12861 | segmented variant). The simulator recognizes which architecture is | |
12862 | appropriate by inspecting the object code. | |
12863 | ||
12864 | @table @code | |
12865 | @item target sim @var{args} | |
12866 | @kindex sim | |
d4f3574e | 12867 | @kindex target sim@r{, with Z8000} |
104c1213 JM |
12868 | Debug programs on a simulated CPU. If the simulator supports setup |
12869 | options, specify them via @var{args}. | |
12870 | @end table | |
12871 | ||
12872 | @noindent | |
12873 | After specifying this target, you can debug programs for the simulated | |
12874 | CPU in the same style as programs for your host computer; use the | |
12875 | @code{file} command to load a new program image, the @code{run} command | |
12876 | to run your program, and so on. | |
12877 | ||
d4f3574e SS |
12878 | As well as making available all the usual machine registers |
12879 | (@pxref{Registers, ,Registers}), the Z8000 simulator provides three | |
12880 | additional items of information as specially named registers: | |
104c1213 JM |
12881 | |
12882 | @table @code | |
12883 | ||
12884 | @item cycles | |
12885 | Counts clock-ticks in the simulator. | |
12886 | ||
12887 | @item insts | |
12888 | Counts instructions run in the simulator. | |
12889 | ||
12890 | @item time | |
12891 | Execution time in 60ths of a second. | |
12892 | ||
12893 | @end table | |
12894 | ||
12895 | You can refer to these values in @value{GDBN} expressions with the usual | |
12896 | conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a | |
12897 | conditional breakpoint that suspends only after at least 5000 | |
12898 | simulated clock ticks. | |
12899 | ||
6d2ebf8b | 12900 | @node Architectures |
104c1213 JM |
12901 | @section Architectures |
12902 | ||
12903 | This section describes characteristics of architectures that affect | |
2df3850c | 12904 | all uses of @value{GDBN} with the architecture, both native and cross. |
104c1213 JM |
12905 | |
12906 | @menu | |
12907 | * A29K:: | |
12908 | * Alpha:: | |
12909 | * MIPS:: | |
12910 | @end menu | |
12911 | ||
6d2ebf8b | 12912 | @node A29K |
104c1213 JM |
12913 | @subsection A29K |
12914 | ||
12915 | @table @code | |
12916 | ||
12917 | @kindex set rstack_high_address | |
12918 | @cindex AMD 29K register stack | |
12919 | @cindex register stack, AMD29K | |
12920 | @item set rstack_high_address @var{address} | |
12921 | On AMD 29000 family processors, registers are saved in a separate | |
d4f3574e | 12922 | @dfn{register stack}. There is no way for @value{GDBN} to determine the |
104c1213 JM |
12923 | extent of this stack. Normally, @value{GDBN} just assumes that the |
12924 | stack is ``large enough''. This may result in @value{GDBN} referencing | |
12925 | memory locations that do not exist. If necessary, you can get around | |
12926 | this problem by specifying the ending address of the register stack with | |
12927 | the @code{set rstack_high_address} command. The argument should be an | |
12928 | address, which you probably want to precede with @samp{0x} to specify in | |
12929 | hexadecimal. | |
12930 | ||
12931 | @kindex show rstack_high_address | |
12932 | @item show rstack_high_address | |
12933 | Display the current limit of the register stack, on AMD 29000 family | |
12934 | processors. | |
12935 | ||
12936 | @end table | |
12937 | ||
6d2ebf8b | 12938 | @node Alpha |
104c1213 JM |
12939 | @subsection Alpha |
12940 | ||
12941 | See the following section. | |
12942 | ||
6d2ebf8b | 12943 | @node MIPS |
104c1213 JM |
12944 | @subsection MIPS |
12945 | ||
12946 | @cindex stack on Alpha | |
12947 | @cindex stack on MIPS | |
12948 | @cindex Alpha stack | |
12949 | @cindex MIPS stack | |
12950 | Alpha- and MIPS-based computers use an unusual stack frame, which | |
12951 | sometimes requires @value{GDBN} to search backward in the object code to | |
12952 | find the beginning of a function. | |
12953 | ||
12954 | @cindex response time, MIPS debugging | |
12955 | To improve response time (especially for embedded applications, where | |
12956 | @value{GDBN} may be restricted to a slow serial line for this search) | |
12957 | you may want to limit the size of this search, using one of these | |
12958 | commands: | |
12959 | ||
12960 | @table @code | |
00e4a2e4 | 12961 | @cindex @code{heuristic-fence-post} (Alpha, MIPS) |
104c1213 JM |
12962 | @item set heuristic-fence-post @var{limit} |
12963 | Restrict @value{GDBN} to examining at most @var{limit} bytes in its | |
12964 | search for the beginning of a function. A value of @var{0} (the | |
12965 | default) means there is no limit. However, except for @var{0}, the | |
12966 | larger the limit the more bytes @code{heuristic-fence-post} must search | |
12967 | and therefore the longer it takes to run. | |
12968 | ||
12969 | @item show heuristic-fence-post | |
12970 | Display the current limit. | |
12971 | @end table | |
12972 | ||
12973 | @noindent | |
12974 | These commands are available @emph{only} when @value{GDBN} is configured | |
12975 | for debugging programs on Alpha or MIPS processors. | |
12976 | ||
12977 | ||
6d2ebf8b | 12978 | @node Controlling GDB |
c906108c SS |
12979 | @chapter Controlling @value{GDBN} |
12980 | ||
53a5351d JM |
12981 | You can alter the way @value{GDBN} interacts with you by using the |
12982 | @code{set} command. For commands controlling how @value{GDBN} displays | |
d4f3574e | 12983 | data, see @ref{Print Settings, ,Print settings}. Other settings are |
53a5351d | 12984 | described here. |
c906108c SS |
12985 | |
12986 | @menu | |
12987 | * Prompt:: Prompt | |
12988 | * Editing:: Command editing | |
12989 | * History:: Command history | |
12990 | * Screen Size:: Screen size | |
12991 | * Numbers:: Numbers | |
12992 | * Messages/Warnings:: Optional warnings and messages | |
5d161b24 | 12993 | * Debugging Output:: Optional messages about internal happenings |
c906108c SS |
12994 | @end menu |
12995 | ||
6d2ebf8b | 12996 | @node Prompt |
c906108c SS |
12997 | @section Prompt |
12998 | ||
12999 | @cindex prompt | |
13000 | ||
13001 | @value{GDBN} indicates its readiness to read a command by printing a string | |
13002 | called the @dfn{prompt}. This string is normally @samp{(@value{GDBP})}. You | |
13003 | can change the prompt string with the @code{set prompt} command. For | |
13004 | instance, when debugging @value{GDBN} with @value{GDBN}, it is useful to change | |
5d161b24 | 13005 | the prompt in one of the @value{GDBN} sessions so that you can always tell |
c906108c SS |
13006 | which one you are talking to. |
13007 | ||
d4f3574e | 13008 | @emph{Note:} @code{set prompt} does not add a space for you after the |
c906108c SS |
13009 | prompt you set. This allows you to set a prompt which ends in a space |
13010 | or a prompt that does not. | |
13011 | ||
13012 | @table @code | |
13013 | @kindex set prompt | |
13014 | @item set prompt @var{newprompt} | |
13015 | Directs @value{GDBN} to use @var{newprompt} as its prompt string henceforth. | |
13016 | ||
13017 | @kindex show prompt | |
13018 | @item show prompt | |
13019 | Prints a line of the form: @samp{Gdb's prompt is: @var{your-prompt}} | |
13020 | @end table | |
13021 | ||
6d2ebf8b | 13022 | @node Editing |
c906108c SS |
13023 | @section Command editing |
13024 | @cindex readline | |
13025 | @cindex command line editing | |
13026 | ||
13027 | @value{GDBN} reads its input commands via the @dfn{readline} interface. This | |
13028 | @sc{gnu} library provides consistent behavior for programs which provide a | |
13029 | command line interface to the user. Advantages are @sc{gnu} Emacs-style | |
13030 | or @dfn{vi}-style inline editing of commands, @code{csh}-like history | |
13031 | substitution, and a storage and recall of command history across | |
13032 | debugging sessions. | |
13033 | ||
13034 | You may control the behavior of command line editing in @value{GDBN} with the | |
13035 | command @code{set}. | |
13036 | ||
13037 | @table @code | |
13038 | @kindex set editing | |
13039 | @cindex editing | |
13040 | @item set editing | |
13041 | @itemx set editing on | |
13042 | Enable command line editing (enabled by default). | |
13043 | ||
13044 | @item set editing off | |
13045 | Disable command line editing. | |
13046 | ||
13047 | @kindex show editing | |
13048 | @item show editing | |
13049 | Show whether command line editing is enabled. | |
13050 | @end table | |
13051 | ||
6d2ebf8b | 13052 | @node History |
c906108c SS |
13053 | @section Command history |
13054 | ||
13055 | @value{GDBN} can keep track of the commands you type during your | |
13056 | debugging sessions, so that you can be certain of precisely what | |
13057 | happened. Use these commands to manage the @value{GDBN} command | |
13058 | history facility. | |
13059 | ||
13060 | @table @code | |
13061 | @cindex history substitution | |
13062 | @cindex history file | |
13063 | @kindex set history filename | |
13064 | @kindex GDBHISTFILE | |
13065 | @item set history filename @var{fname} | |
13066 | Set the name of the @value{GDBN} command history file to @var{fname}. | |
13067 | This is the file where @value{GDBN} reads an initial command history | |
13068 | list, and where it writes the command history from this session when it | |
13069 | exits. You can access this list through history expansion or through | |
13070 | the history command editing characters listed below. This file defaults | |
13071 | to the value of the environment variable @code{GDBHISTFILE}, or to | |
d4f3574e SS |
13072 | @file{./.gdb_history} (@file{./_gdb_history} on MS-DOS) if this variable |
13073 | is not set. | |
c906108c SS |
13074 | |
13075 | @cindex history save | |
13076 | @kindex set history save | |
13077 | @item set history save | |
13078 | @itemx set history save on | |
13079 | Record command history in a file, whose name may be specified with the | |
13080 | @code{set history filename} command. By default, this option is disabled. | |
13081 | ||
13082 | @item set history save off | |
13083 | Stop recording command history in a file. | |
13084 | ||
13085 | @cindex history size | |
13086 | @kindex set history size | |
13087 | @item set history size @var{size} | |
13088 | Set the number of commands which @value{GDBN} keeps in its history list. | |
13089 | This defaults to the value of the environment variable | |
13090 | @code{HISTSIZE}, or to 256 if this variable is not set. | |
13091 | @end table | |
13092 | ||
13093 | @cindex history expansion | |
13094 | History expansion assigns special meaning to the character @kbd{!}. | |
13095 | @ifset have-readline-appendices | |
13096 | @xref{Event Designators}. | |
13097 | @end ifset | |
13098 | ||
13099 | Since @kbd{!} is also the logical not operator in C, history expansion | |
13100 | is off by default. If you decide to enable history expansion with the | |
13101 | @code{set history expansion on} command, you may sometimes need to | |
13102 | follow @kbd{!} (when it is used as logical not, in an expression) with | |
13103 | a space or a tab to prevent it from being expanded. The readline | |
13104 | history facilities do not attempt substitution on the strings | |
13105 | @kbd{!=} and @kbd{!(}, even when history expansion is enabled. | |
13106 | ||
13107 | The commands to control history expansion are: | |
13108 | ||
13109 | @table @code | |
13110 | @kindex set history expansion | |
13111 | @item set history expansion on | |
13112 | @itemx set history expansion | |
13113 | Enable history expansion. History expansion is off by default. | |
13114 | ||
13115 | @item set history expansion off | |
13116 | Disable history expansion. | |
13117 | ||
13118 | The readline code comes with more complete documentation of | |
13119 | editing and history expansion features. Users unfamiliar with @sc{gnu} Emacs | |
13120 | or @code{vi} may wish to read it. | |
13121 | @ifset have-readline-appendices | |
13122 | @xref{Command Line Editing}. | |
13123 | @end ifset | |
13124 | ||
13125 | @c @group | |
13126 | @kindex show history | |
13127 | @item show history | |
13128 | @itemx show history filename | |
13129 | @itemx show history save | |
13130 | @itemx show history size | |
13131 | @itemx show history expansion | |
13132 | These commands display the state of the @value{GDBN} history parameters. | |
13133 | @code{show history} by itself displays all four states. | |
13134 | @c @end group | |
13135 | @end table | |
13136 | ||
13137 | @table @code | |
41afff9a | 13138 | @kindex shows |
c906108c SS |
13139 | @item show commands |
13140 | Display the last ten commands in the command history. | |
13141 | ||
13142 | @item show commands @var{n} | |
13143 | Print ten commands centered on command number @var{n}. | |
13144 | ||
13145 | @item show commands + | |
13146 | Print ten commands just after the commands last printed. | |
13147 | @end table | |
13148 | ||
6d2ebf8b | 13149 | @node Screen Size |
c906108c SS |
13150 | @section Screen size |
13151 | @cindex size of screen | |
13152 | @cindex pauses in output | |
13153 | ||
13154 | Certain commands to @value{GDBN} may produce large amounts of | |
13155 | information output to the screen. To help you read all of it, | |
13156 | @value{GDBN} pauses and asks you for input at the end of each page of | |
13157 | output. Type @key{RET} when you want to continue the output, or @kbd{q} | |
13158 | to discard the remaining output. Also, the screen width setting | |
13159 | determines when to wrap lines of output. Depending on what is being | |
13160 | printed, @value{GDBN} tries to break the line at a readable place, | |
13161 | rather than simply letting it overflow onto the following line. | |
13162 | ||
d4f3574e SS |
13163 | Normally @value{GDBN} knows the size of the screen from the terminal |
13164 | driver software. For example, on Unix @value{GDBN} uses the termcap data base | |
c906108c | 13165 | together with the value of the @code{TERM} environment variable and the |
d4f3574e | 13166 | @code{stty rows} and @code{stty cols} settings. If this is not correct, |
c906108c SS |
13167 | you can override it with the @code{set height} and @code{set |
13168 | width} commands: | |
13169 | ||
13170 | @table @code | |
13171 | @kindex set height | |
13172 | @kindex set width | |
13173 | @kindex show width | |
13174 | @kindex show height | |
13175 | @item set height @var{lpp} | |
13176 | @itemx show height | |
13177 | @itemx set width @var{cpl} | |
13178 | @itemx show width | |
13179 | These @code{set} commands specify a screen height of @var{lpp} lines and | |
13180 | a screen width of @var{cpl} characters. The associated @code{show} | |
13181 | commands display the current settings. | |
13182 | ||
5d161b24 DB |
13183 | If you specify a height of zero lines, @value{GDBN} does not pause during |
13184 | output no matter how long the output is. This is useful if output is to a | |
c906108c SS |
13185 | file or to an editor buffer. |
13186 | ||
13187 | Likewise, you can specify @samp{set width 0} to prevent @value{GDBN} | |
13188 | from wrapping its output. | |
13189 | @end table | |
13190 | ||
6d2ebf8b | 13191 | @node Numbers |
c906108c SS |
13192 | @section Numbers |
13193 | @cindex number representation | |
13194 | @cindex entering numbers | |
13195 | ||
2df3850c JM |
13196 | You can always enter numbers in octal, decimal, or hexadecimal in |
13197 | @value{GDBN} by the usual conventions: octal numbers begin with | |
13198 | @samp{0}, decimal numbers end with @samp{.}, and hexadecimal numbers | |
13199 | begin with @samp{0x}. Numbers that begin with none of these are, by | |
13200 | default, entered in base 10; likewise, the default display for | |
13201 | numbers---when no particular format is specified---is base 10. You can | |
13202 | change the default base for both input and output with the @code{set | |
13203 | radix} command. | |
c906108c SS |
13204 | |
13205 | @table @code | |
13206 | @kindex set input-radix | |
13207 | @item set input-radix @var{base} | |
13208 | Set the default base for numeric input. Supported choices | |
13209 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
13210 | specified either unambiguously or using the current default radix; for | |
13211 | example, any of | |
13212 | ||
13213 | @smallexample | |
13214 | set radix 012 | |
13215 | set radix 10. | |
13216 | set radix 0xa | |
13217 | @end smallexample | |
13218 | ||
13219 | @noindent | |
13220 | sets the base to decimal. On the other hand, @samp{set radix 10} | |
13221 | leaves the radix unchanged no matter what it was. | |
13222 | ||
13223 | @kindex set output-radix | |
13224 | @item set output-radix @var{base} | |
13225 | Set the default base for numeric display. Supported choices | |
13226 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
13227 | specified either unambiguously or using the current default radix. | |
13228 | ||
13229 | @kindex show input-radix | |
13230 | @item show input-radix | |
13231 | Display the current default base for numeric input. | |
13232 | ||
13233 | @kindex show output-radix | |
13234 | @item show output-radix | |
13235 | Display the current default base for numeric display. | |
13236 | @end table | |
13237 | ||
6d2ebf8b | 13238 | @node Messages/Warnings |
c906108c SS |
13239 | @section Optional warnings and messages |
13240 | ||
2df3850c JM |
13241 | By default, @value{GDBN} is silent about its inner workings. If you are |
13242 | running on a slow machine, you may want to use the @code{set verbose} | |
13243 | command. This makes @value{GDBN} tell you when it does a lengthy | |
13244 | internal operation, so you will not think it has crashed. | |
c906108c SS |
13245 | |
13246 | Currently, the messages controlled by @code{set verbose} are those | |
13247 | which announce that the symbol table for a source file is being read; | |
13248 | see @code{symbol-file} in @ref{Files, ,Commands to specify files}. | |
13249 | ||
13250 | @table @code | |
13251 | @kindex set verbose | |
13252 | @item set verbose on | |
13253 | Enables @value{GDBN} output of certain informational messages. | |
13254 | ||
13255 | @item set verbose off | |
13256 | Disables @value{GDBN} output of certain informational messages. | |
13257 | ||
13258 | @kindex show verbose | |
13259 | @item show verbose | |
13260 | Displays whether @code{set verbose} is on or off. | |
13261 | @end table | |
13262 | ||
2df3850c JM |
13263 | By default, if @value{GDBN} encounters bugs in the symbol table of an |
13264 | object file, it is silent; but if you are debugging a compiler, you may | |
13265 | find this information useful (@pxref{Symbol Errors, ,Errors reading | |
13266 | symbol files}). | |
c906108c SS |
13267 | |
13268 | @table @code | |
2df3850c | 13269 | |
c906108c SS |
13270 | @kindex set complaints |
13271 | @item set complaints @var{limit} | |
2df3850c JM |
13272 | Permits @value{GDBN} to output @var{limit} complaints about each type of |
13273 | unusual symbols before becoming silent about the problem. Set | |
13274 | @var{limit} to zero to suppress all complaints; set it to a large number | |
13275 | to prevent complaints from being suppressed. | |
c906108c SS |
13276 | |
13277 | @kindex show complaints | |
13278 | @item show complaints | |
13279 | Displays how many symbol complaints @value{GDBN} is permitted to produce. | |
2df3850c | 13280 | |
c906108c SS |
13281 | @end table |
13282 | ||
13283 | By default, @value{GDBN} is cautious, and asks what sometimes seems to be a | |
13284 | lot of stupid questions to confirm certain commands. For example, if | |
13285 | you try to run a program which is already running: | |
13286 | ||
13287 | @example | |
13288 | (@value{GDBP}) run | |
13289 | The program being debugged has been started already. | |
13290 | Start it from the beginning? (y or n) | |
13291 | @end example | |
13292 | ||
13293 | If you are willing to unflinchingly face the consequences of your own | |
13294 | commands, you can disable this ``feature'': | |
13295 | ||
13296 | @table @code | |
2df3850c | 13297 | |
c906108c SS |
13298 | @kindex set confirm |
13299 | @cindex flinching | |
13300 | @cindex confirmation | |
13301 | @cindex stupid questions | |
13302 | @item set confirm off | |
13303 | Disables confirmation requests. | |
13304 | ||
13305 | @item set confirm on | |
13306 | Enables confirmation requests (the default). | |
13307 | ||
13308 | @kindex show confirm | |
13309 | @item show confirm | |
13310 | Displays state of confirmation requests. | |
2df3850c | 13311 | |
c906108c SS |
13312 | @end table |
13313 | ||
6d2ebf8b | 13314 | @node Debugging Output |
5d161b24 DB |
13315 | @section Optional messages about internal happenings |
13316 | @table @code | |
13317 | @kindex set debug arch | |
13318 | @item set debug arch | |
13319 | Turns on or off display of gdbarch debugging info. The default is off | |
13320 | @kindex show debug arch | |
13321 | @item show debug arch | |
13322 | Displays the current state of displaying gdbarch debugging info. | |
13323 | @kindex set debug event | |
13324 | @item set debug event | |
13325 | Turns on or off display of @value{GDBN} event debugging info. The | |
13326 | default is off. | |
13327 | @kindex show debug event | |
13328 | @item show debug event | |
13329 | Displays the current state of displaying @value{GDBN} event debugging | |
13330 | info. | |
13331 | @kindex set debug expression | |
13332 | @item set debug expression | |
13333 | Turns on or off display of @value{GDBN} expression debugging info. The | |
13334 | default is off. | |
13335 | @kindex show debug expression | |
13336 | @item show debug expression | |
13337 | Displays the current state of displaying @value{GDBN} expression | |
13338 | debugging info. | |
13339 | @kindex set debug overload | |
13340 | @item set debug overload | |
b37052ae | 13341 | Turns on or off display of @value{GDBN} C@t{++} overload debugging |
5d161b24 DB |
13342 | info. This includes info such as ranking of functions, etc. The default |
13343 | is off. | |
13344 | @kindex show debug overload | |
13345 | @item show debug overload | |
b37052ae | 13346 | Displays the current state of displaying @value{GDBN} C@t{++} overload |
5d161b24 DB |
13347 | debugging info. |
13348 | @kindex set debug remote | |
13349 | @cindex packets, reporting on stdout | |
13350 | @cindex serial connections, debugging | |
13351 | @item set debug remote | |
13352 | Turns on or off display of reports on all packets sent back and forth across | |
13353 | the serial line to the remote machine. The info is printed on the | |
13354 | @value{GDBN} standard output stream. The default is off. | |
13355 | @kindex show debug remote | |
13356 | @item show debug remote | |
13357 | Displays the state of display of remote packets. | |
13358 | @kindex set debug serial | |
13359 | @item set debug serial | |
13360 | Turns on or off display of @value{GDBN} serial debugging info. The | |
13361 | default is off. | |
13362 | @kindex show debug serial | |
13363 | @item show debug serial | |
13364 | Displays the current state of displaying @value{GDBN} serial debugging | |
13365 | info. | |
13366 | @kindex set debug target | |
13367 | @item set debug target | |
13368 | Turns on or off display of @value{GDBN} target debugging info. This info | |
13369 | includes what is going on at the target level of GDB, as it happens. The | |
13370 | default is off. | |
13371 | @kindex show debug target | |
13372 | @item show debug target | |
13373 | Displays the current state of displaying @value{GDBN} target debugging | |
13374 | info. | |
13375 | @kindex set debug varobj | |
13376 | @item set debug varobj | |
13377 | Turns on or off display of @value{GDBN} variable object debugging | |
13378 | info. The default is off. | |
13379 | @kindex show debug varobj | |
13380 | @item show debug varobj | |
13381 | Displays the current state of displaying @value{GDBN} variable object | |
13382 | debugging info. | |
13383 | @end table | |
13384 | ||
6d2ebf8b | 13385 | @node Sequences |
c906108c SS |
13386 | @chapter Canned Sequences of Commands |
13387 | ||
13388 | Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint | |
2df3850c JM |
13389 | command lists}), @value{GDBN} provides two ways to store sequences of |
13390 | commands for execution as a unit: user-defined commands and command | |
13391 | files. | |
c906108c SS |
13392 | |
13393 | @menu | |
13394 | * Define:: User-defined commands | |
13395 | * Hooks:: User-defined command hooks | |
13396 | * Command Files:: Command files | |
13397 | * Output:: Commands for controlled output | |
13398 | @end menu | |
13399 | ||
6d2ebf8b | 13400 | @node Define |
c906108c SS |
13401 | @section User-defined commands |
13402 | ||
13403 | @cindex user-defined command | |
2df3850c JM |
13404 | A @dfn{user-defined command} is a sequence of @value{GDBN} commands to |
13405 | which you assign a new name as a command. This is done with the | |
13406 | @code{define} command. User commands may accept up to 10 arguments | |
13407 | separated by whitespace. Arguments are accessed within the user command | |
13408 | via @var{$arg0@dots{}$arg9}. A trivial example: | |
c906108c SS |
13409 | |
13410 | @smallexample | |
13411 | define adder | |
13412 | print $arg0 + $arg1 + $arg2 | |
13413 | @end smallexample | |
13414 | ||
d4f3574e SS |
13415 | @noindent |
13416 | To execute the command use: | |
c906108c SS |
13417 | |
13418 | @smallexample | |
13419 | adder 1 2 3 | |
13420 | @end smallexample | |
13421 | ||
d4f3574e SS |
13422 | @noindent |
13423 | This defines the command @code{adder}, which prints the sum of | |
5d161b24 | 13424 | its three arguments. Note the arguments are text substitutions, so they may |
c906108c SS |
13425 | reference variables, use complex expressions, or even perform inferior |
13426 | functions calls. | |
13427 | ||
13428 | @table @code | |
2df3850c | 13429 | |
c906108c SS |
13430 | @kindex define |
13431 | @item define @var{commandname} | |
13432 | Define a command named @var{commandname}. If there is already a command | |
13433 | by that name, you are asked to confirm that you want to redefine it. | |
13434 | ||
13435 | The definition of the command is made up of other @value{GDBN} command lines, | |
13436 | which are given following the @code{define} command. The end of these | |
13437 | commands is marked by a line containing @code{end}. | |
13438 | ||
13439 | @kindex if | |
13440 | @kindex else | |
13441 | @item if | |
13442 | Takes a single argument, which is an expression to evaluate. | |
13443 | It is followed by a series of commands that are executed | |
13444 | only if the expression is true (nonzero). | |
13445 | There can then optionally be a line @code{else}, followed | |
13446 | by a series of commands that are only executed if the expression | |
13447 | was false. The end of the list is marked by a line containing @code{end}. | |
13448 | ||
13449 | @kindex while | |
13450 | @item while | |
13451 | The syntax is similar to @code{if}: the command takes a single argument, | |
13452 | which is an expression to evaluate, and must be followed by the commands to | |
13453 | execute, one per line, terminated by an @code{end}. | |
13454 | The commands are executed repeatedly as long as the expression | |
13455 | evaluates to true. | |
13456 | ||
13457 | @kindex document | |
13458 | @item document @var{commandname} | |
13459 | Document the user-defined command @var{commandname}, so that it can be | |
5d161b24 DB |
13460 | accessed by @code{help}. The command @var{commandname} must already be |
13461 | defined. This command reads lines of documentation just as @code{define} | |
13462 | reads the lines of the command definition, ending with @code{end}. | |
13463 | After the @code{document} command is finished, @code{help} on command | |
c906108c SS |
13464 | @var{commandname} displays the documentation you have written. |
13465 | ||
13466 | You may use the @code{document} command again to change the | |
13467 | documentation of a command. Redefining the command with @code{define} | |
13468 | does not change the documentation. | |
13469 | ||
13470 | @kindex help user-defined | |
13471 | @item help user-defined | |
13472 | List all user-defined commands, with the first line of the documentation | |
13473 | (if any) for each. | |
13474 | ||
13475 | @kindex show user | |
13476 | @item show user | |
13477 | @itemx show user @var{commandname} | |
2df3850c JM |
13478 | Display the @value{GDBN} commands used to define @var{commandname} (but |
13479 | not its documentation). If no @var{commandname} is given, display the | |
c906108c | 13480 | definitions for all user-defined commands. |
2df3850c | 13481 | |
c906108c SS |
13482 | @end table |
13483 | ||
13484 | When user-defined commands are executed, the | |
13485 | commands of the definition are not printed. An error in any command | |
13486 | stops execution of the user-defined command. | |
13487 | ||
13488 | If used interactively, commands that would ask for confirmation proceed | |
5d161b24 DB |
13489 | without asking when used inside a user-defined command. Many @value{GDBN} |
13490 | commands that normally print messages to say what they are doing omit the | |
c906108c SS |
13491 | messages when used in a user-defined command. |
13492 | ||
6d2ebf8b | 13493 | @node Hooks |
c906108c | 13494 | @section User-defined command hooks |
d4f3574e SS |
13495 | @cindex command hooks |
13496 | @cindex hooks, for commands | |
c78b4128 | 13497 | @cindex hooks, pre-command |
c906108c | 13498 | |
c78b4128 EZ |
13499 | @kindex hook |
13500 | @kindex hook- | |
13501 | You may define @dfn{hooks}, which are a special kind of user-defined | |
c906108c SS |
13502 | command. Whenever you run the command @samp{foo}, if the user-defined |
13503 | command @samp{hook-foo} exists, it is executed (with no arguments) | |
13504 | before that command. | |
13505 | ||
c78b4128 EZ |
13506 | @cindex hooks, post-command |
13507 | @kindex hookpost | |
13508 | @kindex hookpost- | |
13509 | A hook may also be defined which is run after the command you executed. | |
13510 | Whenever you run the command @samp{foo}, if the user-defined command | |
13511 | @samp{hookpost-foo} exists, it is executed (with no arguments) after | |
13512 | that command. Post-execution hooks may exist simultaneously with | |
13513 | pre-execution hooks, for the same command. | |
13514 | ||
13515 | It is valid for a hook to call the command which it hooks. If this | |
13516 | occurs, the hook is not re-executed, thereby avoiding infinte recursion. | |
13517 | ||
13518 | @c It would be nice if hookpost could be passed a parameter indicating | |
13519 | @c if the command it hooks executed properly or not. FIXME! | |
13520 | ||
d4f3574e | 13521 | @kindex stop@r{, a pseudo-command} |
c906108c SS |
13522 | In addition, a pseudo-command, @samp{stop} exists. Defining |
13523 | (@samp{hook-stop}) makes the associated commands execute every time | |
13524 | execution stops in your program: before breakpoint commands are run, | |
13525 | displays are printed, or the stack frame is printed. | |
13526 | ||
c906108c SS |
13527 | For example, to ignore @code{SIGALRM} signals while |
13528 | single-stepping, but treat them normally during normal execution, | |
13529 | you could define: | |
13530 | ||
13531 | @example | |
13532 | define hook-stop | |
13533 | handle SIGALRM nopass | |
13534 | end | |
13535 | ||
13536 | define hook-run | |
13537 | handle SIGALRM pass | |
13538 | end | |
13539 | ||
13540 | define hook-continue | |
13541 | handle SIGLARM pass | |
13542 | end | |
13543 | @end example | |
c906108c | 13544 | |
c78b4128 EZ |
13545 | As a further example, to hook at the begining and end of the @code{echo} |
13546 | command, and to add extra text to the beginning and end of the message, | |
13547 | you could define: | |
13548 | ||
13549 | @example | |
13550 | define hook-echo | |
13551 | echo <<<--- | |
13552 | end | |
13553 | ||
13554 | define hookpost-echo | |
13555 | echo --->>>\n | |
13556 | end | |
13557 | ||
13558 | (@value{GDBP}) echo Hello World | |
13559 | <<<---Hello World--->>> | |
13560 | (@value{GDBP}) | |
13561 | ||
13562 | @end example | |
13563 | ||
c906108c SS |
13564 | You can define a hook for any single-word command in @value{GDBN}, but |
13565 | not for command aliases; you should define a hook for the basic command | |
13566 | name, e.g. @code{backtrace} rather than @code{bt}. | |
13567 | @c FIXME! So how does Joe User discover whether a command is an alias | |
13568 | @c or not? | |
13569 | If an error occurs during the execution of your hook, execution of | |
13570 | @value{GDBN} commands stops and @value{GDBN} issues a prompt | |
13571 | (before the command that you actually typed had a chance to run). | |
13572 | ||
13573 | If you try to define a hook which does not match any known command, you | |
13574 | get a warning from the @code{define} command. | |
13575 | ||
6d2ebf8b | 13576 | @node Command Files |
c906108c SS |
13577 | @section Command files |
13578 | ||
13579 | @cindex command files | |
5d161b24 DB |
13580 | A command file for @value{GDBN} is a file of lines that are @value{GDBN} |
13581 | commands. Comments (lines starting with @kbd{#}) may also be included. | |
13582 | An empty line in a command file does nothing; it does not mean to repeat | |
c906108c SS |
13583 | the last command, as it would from the terminal. |
13584 | ||
13585 | @cindex init file | |
13586 | @cindex @file{.gdbinit} | |
d4f3574e | 13587 | @cindex @file{gdb.ini} |
c906108c | 13588 | When you start @value{GDBN}, it automatically executes commands from its |
96565e91 CF |
13589 | @dfn{init files}, normally called @file{.gdbinit}@footnote{The DJGPP |
13590 | port of @value{GDBN} uses the name @file{gdb.ini} instead, due to the | |
13591 | limitations of file names imposed by DOS filesystems.}. | |
13592 | During startup, @value{GDBN} does the following: | |
bf0184be ND |
13593 | |
13594 | @enumerate | |
13595 | @item | |
13596 | Reads the init file (if any) in your home directory@footnote{On | |
13597 | DOS/Windows systems, the home directory is the one pointed to by the | |
13598 | @code{HOME} environment variable.}. | |
13599 | ||
13600 | @item | |
13601 | Processes command line options and operands. | |
13602 | ||
13603 | @item | |
13604 | Reads the init file (if any) in the current working directory. | |
13605 | ||
13606 | @item | |
13607 | Reads command files specified by the @samp{-x} option. | |
13608 | @end enumerate | |
13609 | ||
13610 | The init file in your home directory can set options (such as @samp{set | |
13611 | complaints}) that affect subsequent processing of command line options | |
13612 | and operands. Init files are not executed if you use the @samp{-nx} | |
13613 | option (@pxref{Mode Options, ,Choosing modes}). | |
c906108c | 13614 | |
c906108c SS |
13615 | @cindex init file name |
13616 | On some configurations of @value{GDBN}, the init file is known by a | |
13617 | different name (these are typically environments where a specialized | |
13618 | form of @value{GDBN} may need to coexist with other forms, hence a | |
13619 | different name for the specialized version's init file). These are the | |
13620 | environments with special init file names: | |
13621 | ||
00e4a2e4 | 13622 | @cindex @file{.vxgdbinit} |
c906108c SS |
13623 | @itemize @bullet |
13624 | @item | |
00e4a2e4 | 13625 | VxWorks (Wind River Systems real-time OS): @file{.vxgdbinit} |
c906108c | 13626 | |
00e4a2e4 | 13627 | @cindex @file{.os68gdbinit} |
c906108c | 13628 | @item |
00e4a2e4 | 13629 | OS68K (Enea Data Systems real-time OS): @file{.os68gdbinit} |
c906108c | 13630 | |
00e4a2e4 | 13631 | @cindex @file{.esgdbinit} |
c906108c | 13632 | @item |
00e4a2e4 | 13633 | ES-1800 (Ericsson Telecom AB M68000 emulator): @file{.esgdbinit} |
c906108c | 13634 | @end itemize |
c906108c SS |
13635 | |
13636 | You can also request the execution of a command file with the | |
13637 | @code{source} command: | |
13638 | ||
13639 | @table @code | |
13640 | @kindex source | |
13641 | @item source @var{filename} | |
13642 | Execute the command file @var{filename}. | |
13643 | @end table | |
13644 | ||
13645 | The lines in a command file are executed sequentially. They are not | |
13646 | printed as they are executed. An error in any command terminates execution | |
13647 | of the command file. | |
13648 | ||
13649 | Commands that would ask for confirmation if used interactively proceed | |
13650 | without asking when used in a command file. Many @value{GDBN} commands that | |
13651 | normally print messages to say what they are doing omit the messages | |
13652 | when called from command files. | |
13653 | ||
b433d00b DH |
13654 | @value{GDBN} also accepts command input from standard input. In this |
13655 | mode, normal output goes to standard output and error output goes to | |
13656 | standard error. Errors in a command file supplied on standard input do | |
13657 | not terminate execution of the command file --- execution continues with | |
13658 | the next command. | |
13659 | ||
13660 | @example | |
13661 | gdb < cmds > log 2>&1 | |
13662 | @end example | |
13663 | ||
13664 | (The syntax above will vary depending on the shell used.) This example | |
13665 | will execute commands from the file @file{cmds}. All output and errors | |
13666 | would be directed to @file{log}. | |
13667 | ||
6d2ebf8b | 13668 | @node Output |
c906108c SS |
13669 | @section Commands for controlled output |
13670 | ||
13671 | During the execution of a command file or a user-defined command, normal | |
13672 | @value{GDBN} output is suppressed; the only output that appears is what is | |
13673 | explicitly printed by the commands in the definition. This section | |
13674 | describes three commands useful for generating exactly the output you | |
13675 | want. | |
13676 | ||
13677 | @table @code | |
13678 | @kindex echo | |
13679 | @item echo @var{text} | |
13680 | @c I do not consider backslash-space a standard C escape sequence | |
13681 | @c because it is not in ANSI. | |
13682 | Print @var{text}. Nonprinting characters can be included in | |
13683 | @var{text} using C escape sequences, such as @samp{\n} to print a | |
13684 | newline. @strong{No newline is printed unless you specify one.} | |
13685 | In addition to the standard C escape sequences, a backslash followed | |
13686 | by a space stands for a space. This is useful for displaying a | |
13687 | string with spaces at the beginning or the end, since leading and | |
5d161b24 | 13688 | trailing spaces are otherwise trimmed from all arguments. |
c906108c SS |
13689 | To print @samp{@w{ }and foo =@w{ }}, use the command |
13690 | @samp{echo \@w{ }and foo = \@w{ }}. | |
13691 | ||
13692 | A backslash at the end of @var{text} can be used, as in C, to continue | |
13693 | the command onto subsequent lines. For example, | |
13694 | ||
13695 | @example | |
13696 | echo This is some text\n\ | |
13697 | which is continued\n\ | |
13698 | onto several lines.\n | |
13699 | @end example | |
13700 | ||
13701 | produces the same output as | |
13702 | ||
13703 | @example | |
13704 | echo This is some text\n | |
13705 | echo which is continued\n | |
13706 | echo onto several lines.\n | |
13707 | @end example | |
13708 | ||
13709 | @kindex output | |
13710 | @item output @var{expression} | |
13711 | Print the value of @var{expression} and nothing but that value: no | |
13712 | newlines, no @samp{$@var{nn} = }. The value is not entered in the | |
5d161b24 | 13713 | value history either. @xref{Expressions, ,Expressions}, for more information |
c906108c SS |
13714 | on expressions. |
13715 | ||
13716 | @item output/@var{fmt} @var{expression} | |
13717 | Print the value of @var{expression} in format @var{fmt}. You can use | |
13718 | the same formats as for @code{print}. @xref{Output Formats,,Output | |
13719 | formats}, for more information. | |
13720 | ||
13721 | @kindex printf | |
13722 | @item printf @var{string}, @var{expressions}@dots{} | |
13723 | Print the values of the @var{expressions} under the control of | |
13724 | @var{string}. The @var{expressions} are separated by commas and may be | |
13725 | either numbers or pointers. Their values are printed as specified by | |
13726 | @var{string}, exactly as if your program were to execute the C | |
13727 | subroutine | |
d4f3574e SS |
13728 | @c FIXME: the above implies that at least all ANSI C formats are |
13729 | @c supported, but it isn't true: %E and %G don't work (or so it seems). | |
13730 | @c Either this is a bug, or the manual should document what formats are | |
13731 | @c supported. | |
c906108c SS |
13732 | |
13733 | @example | |
13734 | printf (@var{string}, @var{expressions}@dots{}); | |
13735 | @end example | |
13736 | ||
13737 | For example, you can print two values in hex like this: | |
13738 | ||
13739 | @smallexample | |
13740 | printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo | |
13741 | @end smallexample | |
13742 | ||
13743 | The only backslash-escape sequences that you can use in the format | |
13744 | string are the simple ones that consist of backslash followed by a | |
13745 | letter. | |
13746 | @end table | |
13747 | ||
c4555f82 SC |
13748 | @node TUI |
13749 | @chapter @value{GDBN} Text User Interface | |
13750 | @cindex TUI | |
13751 | ||
13752 | @menu | |
13753 | * TUI Overview:: TUI overview | |
13754 | * TUI Keys:: TUI key bindings | |
13755 | * TUI Commands:: TUI specific commands | |
13756 | * TUI Configuration:: TUI configuration variables | |
13757 | @end menu | |
13758 | ||
13759 | The @value{GDBN} Text User Interface, TUI in short, | |
13760 | is a terminal interface which uses the @code{curses} library | |
13761 | to show the source file, the assembly output, the program registers | |
13762 | and @value{GDBN} commands in separate text windows. | |
13763 | The TUI is available only when @value{GDBN} is configured | |
13764 | with the @code{--enable-tui} configure option (@pxref{Configure Options}). | |
13765 | ||
13766 | @node TUI Overview | |
13767 | @section TUI overview | |
13768 | ||
13769 | The TUI has two display modes that can be switched while | |
13770 | @value{GDBN} runs: | |
13771 | ||
13772 | @itemize @bullet | |
13773 | @item | |
13774 | A curses (or TUI) mode in which it displays several text | |
13775 | windows on the terminal. | |
13776 | ||
13777 | @item | |
13778 | A standard mode which corresponds to the @value{GDBN} configured without | |
13779 | the TUI. | |
13780 | @end itemize | |
13781 | ||
13782 | In the TUI mode, @value{GDBN} can display several text window | |
13783 | on the terminal: | |
13784 | ||
13785 | @table @emph | |
13786 | @item command | |
13787 | This window is the @value{GDBN} command window with the @value{GDBN} | |
13788 | prompt and the @value{GDBN} outputs. The @value{GDBN} input is still | |
13789 | managed using readline but through the TUI. The @emph{command} | |
13790 | window is always visible. | |
13791 | ||
13792 | @item source | |
13793 | The source window shows the source file of the program. The current | |
13794 | line as well as active breakpoints are displayed in this window. | |
13795 | The current program position is shown with the @samp{>} marker and | |
13796 | active breakpoints are shown with @samp{*} markers. | |
13797 | ||
13798 | @item assembly | |
13799 | The assembly window shows the disassembly output of the program. | |
13800 | ||
13801 | @item register | |
13802 | This window shows the processor registers. It detects when | |
13803 | a register is changed and when this is the case, registers that have | |
13804 | changed are highlighted. | |
13805 | ||
13806 | @end table | |
13807 | ||
13808 | The source, assembly and register windows are attached to the thread | |
13809 | and the frame position. They are updated when the current thread | |
13810 | changes, when the frame changes or when the program counter changes. | |
13811 | These three windows are arranged by the TUI according to several | |
13812 | layouts. The layout defines which of these three windows are visible. | |
13813 | The following layouts are available: | |
13814 | ||
13815 | @itemize @bullet | |
13816 | @item | |
13817 | source | |
13818 | ||
13819 | @item | |
13820 | assembly | |
13821 | ||
13822 | @item | |
13823 | source and assembly | |
13824 | ||
13825 | @item | |
13826 | source and registers | |
13827 | ||
13828 | @item | |
13829 | assembly and registers | |
13830 | ||
13831 | @end itemize | |
13832 | ||
13833 | @node TUI Keys | |
13834 | @section TUI Key Bindings | |
13835 | @cindex TUI key bindings | |
13836 | ||
13837 | The TUI installs several key bindings in the readline keymaps | |
13838 | (@pxref{Command Line Editing}). | |
13839 | They allow to leave or enter in the TUI mode or they operate | |
13840 | directly on the TUI layout and windows. The following key bindings | |
13841 | are installed for both TUI mode and the @value{GDBN} standard mode. | |
13842 | ||
13843 | @table @kbd | |
13844 | @kindex C-x C-a | |
13845 | @item C-x C-a | |
13846 | @kindex C-x a | |
13847 | @itemx C-x a | |
13848 | @kindex C-x A | |
13849 | @itemx C-x A | |
13850 | Enter or leave the TUI mode. When the TUI mode is left, | |
13851 | the curses window management is left and @value{GDBN} operates using | |
13852 | its standard mode writing on the terminal directly. When the TUI | |
13853 | mode is entered, the control is given back to the curses windows. | |
13854 | The screen is then refreshed. | |
13855 | ||
13856 | @kindex C-x 1 | |
13857 | @item C-x 1 | |
13858 | Use a TUI layout with only one window. The layout will | |
13859 | either be @samp{source} or @samp{assembly}. When the TUI mode | |
13860 | is not active, it will switch to the TUI mode. | |
13861 | ||
13862 | Think of this key binding as the Emacs @kbd{C-x 1} binding. | |
13863 | ||
13864 | @kindex C-x 2 | |
13865 | @item C-x 2 | |
13866 | Use a TUI layout with at least two windows. When the current | |
13867 | layout shows already two windows, a next layout with two windows is used. | |
13868 | When a new layout is chosen, one window will always be common to the | |
13869 | previous layout and the new one. | |
13870 | ||
13871 | Think of it as the Emacs @kbd{C-x 2} binding. | |
13872 | ||
13873 | @end table | |
13874 | ||
13875 | The following key bindings are handled only by the TUI mode: | |
13876 | ||
13877 | @table @key | |
13878 | @kindex PgUp | |
13879 | @item PgUp | |
13880 | Scroll the active window one page up. | |
13881 | ||
13882 | @kindex PgDn | |
13883 | @item PgDn | |
13884 | Scroll the active window one page down. | |
13885 | ||
13886 | @kindex Up | |
13887 | @item Up | |
13888 | Scroll the active window one line up. | |
13889 | ||
13890 | @kindex Down | |
13891 | @item Down | |
13892 | Scroll the active window one line down. | |
13893 | ||
13894 | @kindex Left | |
13895 | @item Left | |
13896 | Scroll the active window one column left. | |
13897 | ||
13898 | @kindex Right | |
13899 | @item Right | |
13900 | Scroll the active window one column right. | |
13901 | ||
13902 | @kindex C-L | |
13903 | @item C-L | |
13904 | Refresh the screen. | |
13905 | ||
13906 | @end table | |
13907 | ||
13908 | In the TUI mode, the arrow keys are used by the active window | |
13909 | for scrolling. This means they are not available for readline. It is | |
13910 | necessary to use other readline key bindings such as @key{C-p}, @key{C-n}, | |
13911 | @key{C-b} and @key{C-f}. | |
13912 | ||
13913 | @node TUI Commands | |
13914 | @section TUI specific commands | |
13915 | @cindex TUI commands | |
13916 | ||
13917 | The TUI has specific commands to control the text windows. | |
13918 | These commands are always available, that is they do not depend on | |
13919 | the current terminal mode in which @value{GDBN} runs. When @value{GDBN} | |
13920 | is in the standard mode, using these commands will automatically switch | |
13921 | in the TUI mode. | |
13922 | ||
13923 | @table @code | |
13924 | @item layout next | |
13925 | @kindex layout next | |
13926 | Display the next layout. | |
13927 | ||
13928 | @item layout prev | |
13929 | @kindex layout prev | |
13930 | Display the previous layout. | |
13931 | ||
13932 | @item layout src | |
13933 | @kindex layout src | |
13934 | Display the source window only. | |
13935 | ||
13936 | @item layout asm | |
13937 | @kindex layout asm | |
13938 | Display the assembly window only. | |
13939 | ||
13940 | @item layout split | |
13941 | @kindex layout split | |
13942 | Display the source and assembly window. | |
13943 | ||
13944 | @item layout regs | |
13945 | @kindex layout regs | |
13946 | Display the register window together with the source or assembly window. | |
13947 | ||
13948 | @item focus next | prev | src | asm | regs | split | |
13949 | @kindex focus | |
13950 | Set the focus to the named window. | |
13951 | This command allows to change the active window so that scrolling keys | |
13952 | can be affected to another window. | |
13953 | ||
13954 | @item refresh | |
13955 | @kindex refresh | |
13956 | Refresh the screen. This is similar to using @key{C-L} key. | |
13957 | ||
13958 | @item update | |
13959 | @kindex update | |
13960 | Update the source window and the current execution point. | |
13961 | ||
13962 | @item winheight @var{name} +@var{count} | |
13963 | @itemx winheight @var{name} -@var{count} | |
13964 | @kindex winheight | |
13965 | Change the height of the window @var{name} by @var{count} | |
13966 | lines. Positive counts increase the height, while negative counts | |
13967 | decrease it. | |
13968 | ||
13969 | @end table | |
13970 | ||
13971 | @node TUI Configuration | |
13972 | @section TUI configuration variables | |
13973 | @cindex TUI configuration variables | |
13974 | ||
13975 | The TUI has several configuration variables that control the | |
13976 | appearance of windows on the terminal. | |
13977 | ||
13978 | @table @code | |
732b3002 SC |
13979 | @item set tui border-kind @var{kind} |
13980 | @kindex set tui border-kind | |
c4555f82 SC |
13981 | Select the border appearance for the source, assembly and register windows. |
13982 | The possible values are the following: | |
13983 | @table @code | |
13984 | @item space | |
13985 | Use a space character to draw the border. | |
13986 | ||
13987 | @item ascii | |
13988 | Use ascii characters + - and | to draw the border. | |
13989 | ||
13990 | @item acs | |
13991 | Use the Alternate Character Set to draw the border. The border is | |
13992 | drawn using character line graphics if the terminal supports them. | |
13993 | ||
13994 | @end table | |
13995 | ||
732b3002 SC |
13996 | @item set tui active-border-mode @var{mode} |
13997 | @kindex set tui active-border-mode | |
c4555f82 SC |
13998 | Select the attributes to display the border of the active window. |
13999 | The possible values are @code{normal}, @code{standout}, @code{reverse}, | |
14000 | @code{half}, @code{half-standout}, @code{bold} and @code{bold-standout}. | |
14001 | ||
732b3002 SC |
14002 | @item set tui border-mode @var{mode} |
14003 | @kindex set tui border-mode | |
c4555f82 SC |
14004 | Select the attributes to display the border of other windows. |
14005 | The @var{mode} can be one of the following: | |
14006 | @table @code | |
14007 | @item normal | |
14008 | Use normal attributes to display the border. | |
14009 | ||
14010 | @item standout | |
14011 | Use standout mode. | |
14012 | ||
14013 | @item reverse | |
14014 | Use reverse video mode. | |
14015 | ||
14016 | @item half | |
14017 | Use half bright mode. | |
14018 | ||
14019 | @item half-standout | |
14020 | Use half bright and standout mode. | |
14021 | ||
14022 | @item bold | |
14023 | Use extra bright or bold mode. | |
14024 | ||
14025 | @item bold-standout | |
14026 | Use extra bright or bold and standout mode. | |
14027 | ||
14028 | @end table | |
14029 | ||
14030 | @end table | |
14031 | ||
6d2ebf8b | 14032 | @node Emacs |
c906108c SS |
14033 | @chapter Using @value{GDBN} under @sc{gnu} Emacs |
14034 | ||
14035 | @cindex Emacs | |
14036 | @cindex @sc{gnu} Emacs | |
14037 | A special interface allows you to use @sc{gnu} Emacs to view (and | |
14038 | edit) the source files for the program you are debugging with | |
14039 | @value{GDBN}. | |
14040 | ||
14041 | To use this interface, use the command @kbd{M-x gdb} in Emacs. Give the | |
14042 | executable file you want to debug as an argument. This command starts | |
14043 | @value{GDBN} as a subprocess of Emacs, with input and output through a newly | |
14044 | created Emacs buffer. | |
53a5351d | 14045 | @c (Do not use the @code{-tui} option to run @value{GDBN} from Emacs.) |
c906108c SS |
14046 | |
14047 | Using @value{GDBN} under Emacs is just like using @value{GDBN} normally except for two | |
14048 | things: | |
14049 | ||
14050 | @itemize @bullet | |
14051 | @item | |
14052 | All ``terminal'' input and output goes through the Emacs buffer. | |
14053 | @end itemize | |
14054 | ||
14055 | This applies both to @value{GDBN} commands and their output, and to the input | |
14056 | and output done by the program you are debugging. | |
14057 | ||
14058 | This is useful because it means that you can copy the text of previous | |
14059 | commands and input them again; you can even use parts of the output | |
14060 | in this way. | |
14061 | ||
14062 | All the facilities of Emacs' Shell mode are available for interacting | |
14063 | with your program. In particular, you can send signals the usual | |
14064 | way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a | |
14065 | stop. | |
14066 | ||
14067 | @itemize @bullet | |
14068 | @item | |
14069 | @value{GDBN} displays source code through Emacs. | |
14070 | @end itemize | |
14071 | ||
14072 | Each time @value{GDBN} displays a stack frame, Emacs automatically finds the | |
14073 | source file for that frame and puts an arrow (@samp{=>}) at the | |
14074 | left margin of the current line. Emacs uses a separate buffer for | |
14075 | source display, and splits the screen to show both your @value{GDBN} session | |
14076 | and the source. | |
14077 | ||
14078 | Explicit @value{GDBN} @code{list} or search commands still produce output as | |
14079 | usual, but you probably have no reason to use them from Emacs. | |
14080 | ||
14081 | @quotation | |
14082 | @emph{Warning:} If the directory where your program resides is not your | |
14083 | current directory, it can be easy to confuse Emacs about the location of | |
14084 | the source files, in which case the auxiliary display buffer does not | |
14085 | appear to show your source. @value{GDBN} can find programs by searching your | |
14086 | environment's @code{PATH} variable, so the @value{GDBN} input and output | |
14087 | session proceeds normally; but Emacs does not get enough information | |
14088 | back from @value{GDBN} to locate the source files in this situation. To | |
14089 | avoid this problem, either start @value{GDBN} mode from the directory where | |
14090 | your program resides, or specify an absolute file name when prompted for the | |
14091 | @kbd{M-x gdb} argument. | |
14092 | ||
14093 | A similar confusion can result if you use the @value{GDBN} @code{file} command to | |
14094 | switch to debugging a program in some other location, from an existing | |
14095 | @value{GDBN} buffer in Emacs. | |
14096 | @end quotation | |
14097 | ||
14098 | By default, @kbd{M-x gdb} calls the program called @file{gdb}. If | |
14099 | you need to call @value{GDBN} by a different name (for example, if you keep | |
14100 | several configurations around, with different names) you can set the | |
14101 | Emacs variable @code{gdb-command-name}; for example, | |
14102 | ||
14103 | @example | |
14104 | (setq gdb-command-name "mygdb") | |
14105 | @end example | |
14106 | ||
14107 | @noindent | |
d4f3574e | 14108 | (preceded by @kbd{M-:} or @kbd{ESC :}, or typed in the @code{*scratch*} buffer, or |
c906108c SS |
14109 | in your @file{.emacs} file) makes Emacs call the program named |
14110 | ``@code{mygdb}'' instead. | |
14111 | ||
14112 | In the @value{GDBN} I/O buffer, you can use these special Emacs commands in | |
14113 | addition to the standard Shell mode commands: | |
14114 | ||
14115 | @table @kbd | |
14116 | @item C-h m | |
14117 | Describe the features of Emacs' @value{GDBN} Mode. | |
14118 | ||
14119 | @item M-s | |
14120 | Execute to another source line, like the @value{GDBN} @code{step} command; also | |
14121 | update the display window to show the current file and location. | |
14122 | ||
14123 | @item M-n | |
14124 | Execute to next source line in this function, skipping all function | |
14125 | calls, like the @value{GDBN} @code{next} command. Then update the display window | |
14126 | to show the current file and location. | |
14127 | ||
14128 | @item M-i | |
14129 | Execute one instruction, like the @value{GDBN} @code{stepi} command; update | |
14130 | display window accordingly. | |
14131 | ||
14132 | @item M-x gdb-nexti | |
14133 | Execute to next instruction, using the @value{GDBN} @code{nexti} command; update | |
14134 | display window accordingly. | |
14135 | ||
14136 | @item C-c C-f | |
14137 | Execute until exit from the selected stack frame, like the @value{GDBN} | |
14138 | @code{finish} command. | |
14139 | ||
14140 | @item M-c | |
14141 | Continue execution of your program, like the @value{GDBN} @code{continue} | |
14142 | command. | |
14143 | ||
14144 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-p}. | |
14145 | ||
14146 | @item M-u | |
14147 | Go up the number of frames indicated by the numeric argument | |
14148 | (@pxref{Arguments, , Numeric Arguments, Emacs, The @sc{gnu} Emacs Manual}), | |
14149 | like the @value{GDBN} @code{up} command. | |
14150 | ||
14151 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-u}. | |
14152 | ||
14153 | @item M-d | |
14154 | Go down the number of frames indicated by the numeric argument, like the | |
14155 | @value{GDBN} @code{down} command. | |
14156 | ||
14157 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-d}. | |
14158 | ||
14159 | @item C-x & | |
14160 | Read the number where the cursor is positioned, and insert it at the end | |
14161 | of the @value{GDBN} I/O buffer. For example, if you wish to disassemble code | |
14162 | around an address that was displayed earlier, type @kbd{disassemble}; | |
14163 | then move the cursor to the address display, and pick up the | |
14164 | argument for @code{disassemble} by typing @kbd{C-x &}. | |
14165 | ||
14166 | You can customize this further by defining elements of the list | |
14167 | @code{gdb-print-command}; once it is defined, you can format or | |
14168 | otherwise process numbers picked up by @kbd{C-x &} before they are | |
14169 | inserted. A numeric argument to @kbd{C-x &} indicates that you | |
14170 | wish special formatting, and also acts as an index to pick an element of the | |
14171 | list. If the list element is a string, the number to be inserted is | |
14172 | formatted using the Emacs function @code{format}; otherwise the number | |
14173 | is passed as an argument to the corresponding list element. | |
14174 | @end table | |
14175 | ||
14176 | In any source file, the Emacs command @kbd{C-x SPC} (@code{gdb-break}) | |
14177 | tells @value{GDBN} to set a breakpoint on the source line point is on. | |
14178 | ||
14179 | If you accidentally delete the source-display buffer, an easy way to get | |
14180 | it back is to type the command @code{f} in the @value{GDBN} buffer, to | |
14181 | request a frame display; when you run under Emacs, this recreates | |
14182 | the source buffer if necessary to show you the context of the current | |
14183 | frame. | |
14184 | ||
14185 | The source files displayed in Emacs are in ordinary Emacs buffers | |
14186 | which are visiting the source files in the usual way. You can edit | |
14187 | the files with these buffers if you wish; but keep in mind that @value{GDBN} | |
14188 | communicates with Emacs in terms of line numbers. If you add or | |
14189 | delete lines from the text, the line numbers that @value{GDBN} knows cease | |
14190 | to correspond properly with the code. | |
14191 | ||
14192 | @c The following dropped because Epoch is nonstandard. Reactivate | |
14193 | @c if/when v19 does something similar. ---doc@cygnus.com 19dec1990 | |
14194 | @ignore | |
14195 | @kindex Emacs Epoch environment | |
14196 | @kindex Epoch | |
14197 | @kindex inspect | |
14198 | ||
5d161b24 | 14199 | Version 18 of @sc{gnu} Emacs has a built-in window system |
c906108c SS |
14200 | called the @code{epoch} |
14201 | environment. Users of this environment can use a new command, | |
14202 | @code{inspect} which performs identically to @code{print} except that | |
14203 | each value is printed in its own window. | |
14204 | @end ignore | |
c906108c | 14205 | |
d700128c | 14206 | @include annotate.texi |
7162c0ca | 14207 | @include gdbmi.texinfo |
d700128c | 14208 | |
6d2ebf8b | 14209 | @node GDB Bugs |
c906108c SS |
14210 | @chapter Reporting Bugs in @value{GDBN} |
14211 | @cindex bugs in @value{GDBN} | |
14212 | @cindex reporting bugs in @value{GDBN} | |
14213 | ||
14214 | Your bug reports play an essential role in making @value{GDBN} reliable. | |
14215 | ||
14216 | Reporting a bug may help you by bringing a solution to your problem, or it | |
14217 | may not. But in any case the principal function of a bug report is to help | |
14218 | the entire community by making the next version of @value{GDBN} work better. Bug | |
14219 | reports are your contribution to the maintenance of @value{GDBN}. | |
14220 | ||
14221 | In order for a bug report to serve its purpose, you must include the | |
14222 | information that enables us to fix the bug. | |
14223 | ||
14224 | @menu | |
14225 | * Bug Criteria:: Have you found a bug? | |
14226 | * Bug Reporting:: How to report bugs | |
14227 | @end menu | |
14228 | ||
6d2ebf8b | 14229 | @node Bug Criteria |
c906108c SS |
14230 | @section Have you found a bug? |
14231 | @cindex bug criteria | |
14232 | ||
14233 | If you are not sure whether you have found a bug, here are some guidelines: | |
14234 | ||
14235 | @itemize @bullet | |
14236 | @cindex fatal signal | |
14237 | @cindex debugger crash | |
14238 | @cindex crash of debugger | |
14239 | @item | |
14240 | If the debugger gets a fatal signal, for any input whatever, that is a | |
14241 | @value{GDBN} bug. Reliable debuggers never crash. | |
14242 | ||
14243 | @cindex error on valid input | |
14244 | @item | |
14245 | If @value{GDBN} produces an error message for valid input, that is a | |
14246 | bug. (Note that if you're cross debugging, the problem may also be | |
14247 | somewhere in the connection to the target.) | |
14248 | ||
14249 | @cindex invalid input | |
14250 | @item | |
14251 | If @value{GDBN} does not produce an error message for invalid input, | |
14252 | that is a bug. However, you should note that your idea of | |
14253 | ``invalid input'' might be our idea of ``an extension'' or ``support | |
14254 | for traditional practice''. | |
14255 | ||
14256 | @item | |
14257 | If you are an experienced user of debugging tools, your suggestions | |
14258 | for improvement of @value{GDBN} are welcome in any case. | |
14259 | @end itemize | |
14260 | ||
6d2ebf8b | 14261 | @node Bug Reporting |
c906108c SS |
14262 | @section How to report bugs |
14263 | @cindex bug reports | |
14264 | @cindex @value{GDBN} bugs, reporting | |
14265 | ||
c906108c SS |
14266 | A number of companies and individuals offer support for @sc{gnu} products. |
14267 | If you obtained @value{GDBN} from a support organization, we recommend you | |
14268 | contact that organization first. | |
14269 | ||
14270 | You can find contact information for many support companies and | |
14271 | individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs | |
14272 | distribution. | |
14273 | @c should add a web page ref... | |
14274 | ||
14275 | In any event, we also recommend that you send bug reports for | |
14276 | @value{GDBN} to this addresses: | |
14277 | ||
14278 | @example | |
d4f3574e | 14279 | bug-gdb@@gnu.org |
c906108c SS |
14280 | @end example |
14281 | ||
14282 | @strong{Do not send bug reports to @samp{info-gdb}, or to | |
d4f3574e | 14283 | @samp{help-gdb}, or to any newsgroups.} Most users of @value{GDBN} do |
c906108c SS |
14284 | not want to receive bug reports. Those that do have arranged to receive |
14285 | @samp{bug-gdb}. | |
14286 | ||
14287 | The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which | |
14288 | serves as a repeater. The mailing list and the newsgroup carry exactly | |
14289 | the same messages. Often people think of posting bug reports to the | |
14290 | newsgroup instead of mailing them. This appears to work, but it has one | |
14291 | problem which can be crucial: a newsgroup posting often lacks a mail | |
14292 | path back to the sender. Thus, if we need to ask for more information, | |
14293 | we may be unable to reach you. For this reason, it is better to send | |
14294 | bug reports to the mailing list. | |
14295 | ||
14296 | As a last resort, send bug reports on paper to: | |
14297 | ||
14298 | @example | |
14299 | @sc{gnu} Debugger Bugs | |
14300 | Free Software Foundation Inc. | |
14301 | 59 Temple Place - Suite 330 | |
14302 | Boston, MA 02111-1307 | |
14303 | USA | |
14304 | @end example | |
c906108c SS |
14305 | |
14306 | The fundamental principle of reporting bugs usefully is this: | |
14307 | @strong{report all the facts}. If you are not sure whether to state a | |
14308 | fact or leave it out, state it! | |
14309 | ||
14310 | Often people omit facts because they think they know what causes the | |
14311 | problem and assume that some details do not matter. Thus, you might | |
14312 | assume that the name of the variable you use in an example does not matter. | |
14313 | Well, probably it does not, but one cannot be sure. Perhaps the bug is a | |
14314 | stray memory reference which happens to fetch from the location where that | |
14315 | name is stored in memory; perhaps, if the name were different, the contents | |
14316 | of that location would fool the debugger into doing the right thing despite | |
14317 | the bug. Play it safe and give a specific, complete example. That is the | |
14318 | easiest thing for you to do, and the most helpful. | |
14319 | ||
14320 | Keep in mind that the purpose of a bug report is to enable us to fix the | |
14321 | bug. It may be that the bug has been reported previously, but neither | |
14322 | you nor we can know that unless your bug report is complete and | |
14323 | self-contained. | |
14324 | ||
14325 | Sometimes people give a few sketchy facts and ask, ``Does this ring a | |
14326 | bell?'' Those bug reports are useless, and we urge everyone to | |
14327 | @emph{refuse to respond to them} except to chide the sender to report | |
14328 | bugs properly. | |
14329 | ||
14330 | To enable us to fix the bug, you should include all these things: | |
14331 | ||
14332 | @itemize @bullet | |
14333 | @item | |
14334 | The version of @value{GDBN}. @value{GDBN} announces it if you start | |
14335 | with no arguments; you can also print it at any time using @code{show | |
14336 | version}. | |
14337 | ||
14338 | Without this, we will not know whether there is any point in looking for | |
14339 | the bug in the current version of @value{GDBN}. | |
14340 | ||
14341 | @item | |
14342 | The type of machine you are using, and the operating system name and | |
14343 | version number. | |
14344 | ||
c906108c SS |
14345 | @item |
14346 | What compiler (and its version) was used to compile @value{GDBN}---e.g. | |
14347 | ``@value{GCC}--2.8.1''. | |
c906108c SS |
14348 | |
14349 | @item | |
14350 | What compiler (and its version) was used to compile the program you are | |
14351 | debugging---e.g. ``@value{GCC}--2.8.1'', or ``HP92453-01 A.10.32.03 HP | |
14352 | C Compiler''. For GCC, you can say @code{gcc --version} to get this | |
14353 | information; for other compilers, see the documentation for those | |
14354 | compilers. | |
14355 | ||
14356 | @item | |
14357 | The command arguments you gave the compiler to compile your example and | |
14358 | observe the bug. For example, did you use @samp{-O}? To guarantee | |
14359 | you will not omit something important, list them all. A copy of the | |
14360 | Makefile (or the output from make) is sufficient. | |
14361 | ||
14362 | If we were to try to guess the arguments, we would probably guess wrong | |
14363 | and then we might not encounter the bug. | |
14364 | ||
14365 | @item | |
14366 | A complete input script, and all necessary source files, that will | |
14367 | reproduce the bug. | |
14368 | ||
14369 | @item | |
14370 | A description of what behavior you observe that you believe is | |
14371 | incorrect. For example, ``It gets a fatal signal.'' | |
14372 | ||
14373 | Of course, if the bug is that @value{GDBN} gets a fatal signal, then we | |
14374 | will certainly notice it. But if the bug is incorrect output, we might | |
14375 | not notice unless it is glaringly wrong. You might as well not give us | |
14376 | a chance to make a mistake. | |
14377 | ||
14378 | Even if the problem you experience is a fatal signal, you should still | |
14379 | say so explicitly. Suppose something strange is going on, such as, your | |
14380 | copy of @value{GDBN} is out of synch, or you have encountered a bug in | |
14381 | the C library on your system. (This has happened!) Your copy might | |
14382 | crash and ours would not. If you told us to expect a crash, then when | |
14383 | ours fails to crash, we would know that the bug was not happening for | |
14384 | us. If you had not told us to expect a crash, then we would not be able | |
14385 | to draw any conclusion from our observations. | |
14386 | ||
c906108c SS |
14387 | @item |
14388 | If you wish to suggest changes to the @value{GDBN} source, send us context | |
14389 | diffs. If you even discuss something in the @value{GDBN} source, refer to | |
14390 | it by context, not by line number. | |
14391 | ||
14392 | The line numbers in our development sources will not match those in your | |
14393 | sources. Your line numbers would convey no useful information to us. | |
53a5351d | 14394 | |
c906108c SS |
14395 | @end itemize |
14396 | ||
14397 | Here are some things that are not necessary: | |
14398 | ||
14399 | @itemize @bullet | |
14400 | @item | |
14401 | A description of the envelope of the bug. | |
14402 | ||
14403 | Often people who encounter a bug spend a lot of time investigating | |
14404 | which changes to the input file will make the bug go away and which | |
14405 | changes will not affect it. | |
14406 | ||
14407 | This is often time consuming and not very useful, because the way we | |
14408 | will find the bug is by running a single example under the debugger | |
14409 | with breakpoints, not by pure deduction from a series of examples. | |
14410 | We recommend that you save your time for something else. | |
14411 | ||
14412 | Of course, if you can find a simpler example to report @emph{instead} | |
14413 | of the original one, that is a convenience for us. Errors in the | |
14414 | output will be easier to spot, running under the debugger will take | |
14415 | less time, and so on. | |
14416 | ||
14417 | However, simplification is not vital; if you do not want to do this, | |
14418 | report the bug anyway and send us the entire test case you used. | |
14419 | ||
14420 | @item | |
14421 | A patch for the bug. | |
14422 | ||
14423 | A patch for the bug does help us if it is a good one. But do not omit | |
14424 | the necessary information, such as the test case, on the assumption that | |
14425 | a patch is all we need. We might see problems with your patch and decide | |
14426 | to fix the problem another way, or we might not understand it at all. | |
14427 | ||
14428 | Sometimes with a program as complicated as @value{GDBN} it is very hard to | |
14429 | construct an example that will make the program follow a certain path | |
14430 | through the code. If you do not send us the example, we will not be able | |
14431 | to construct one, so we will not be able to verify that the bug is fixed. | |
14432 | ||
14433 | And if we cannot understand what bug you are trying to fix, or why your | |
14434 | patch should be an improvement, we will not install it. A test case will | |
14435 | help us to understand. | |
14436 | ||
14437 | @item | |
14438 | A guess about what the bug is or what it depends on. | |
14439 | ||
14440 | Such guesses are usually wrong. Even we cannot guess right about such | |
14441 | things without first using the debugger to find the facts. | |
14442 | @end itemize | |
14443 | ||
5d161b24 | 14444 | @c The readline documentation is distributed with the readline code |
c906108c SS |
14445 | @c and consists of the two following files: |
14446 | @c rluser.texinfo | |
7be570e7 | 14447 | @c inc-hist.texinfo |
c906108c SS |
14448 | @c Use -I with makeinfo to point to the appropriate directory, |
14449 | @c environment var TEXINPUTS with TeX. | |
14450 | @include rluser.texinfo | |
7be570e7 | 14451 | @include inc-hist.texinfo |
c906108c SS |
14452 | |
14453 | ||
6d2ebf8b | 14454 | @node Formatting Documentation |
c906108c SS |
14455 | @appendix Formatting Documentation |
14456 | ||
14457 | @cindex @value{GDBN} reference card | |
14458 | @cindex reference card | |
14459 | The @value{GDBN} 4 release includes an already-formatted reference card, ready | |
14460 | for printing with PostScript or Ghostscript, in the @file{gdb} | |
14461 | subdirectory of the main source directory@footnote{In | |
14462 | @file{gdb-@value{GDBVN}/gdb/refcard.ps} of the version @value{GDBVN} | |
14463 | release.}. If you can use PostScript or Ghostscript with your printer, | |
14464 | you can print the reference card immediately with @file{refcard.ps}. | |
14465 | ||
14466 | The release also includes the source for the reference card. You | |
14467 | can format it, using @TeX{}, by typing: | |
14468 | ||
14469 | @example | |
14470 | make refcard.dvi | |
14471 | @end example | |
14472 | ||
5d161b24 DB |
14473 | The @value{GDBN} reference card is designed to print in @dfn{landscape} |
14474 | mode on US ``letter'' size paper; | |
c906108c SS |
14475 | that is, on a sheet 11 inches wide by 8.5 inches |
14476 | high. You will need to specify this form of printing as an option to | |
14477 | your @sc{dvi} output program. | |
14478 | ||
14479 | @cindex documentation | |
14480 | ||
14481 | All the documentation for @value{GDBN} comes as part of the machine-readable | |
14482 | distribution. The documentation is written in Texinfo format, which is | |
14483 | a documentation system that uses a single source file to produce both | |
14484 | on-line information and a printed manual. You can use one of the Info | |
14485 | formatting commands to create the on-line version of the documentation | |
14486 | and @TeX{} (or @code{texi2roff}) to typeset the printed version. | |
14487 | ||
14488 | @value{GDBN} includes an already formatted copy of the on-line Info | |
14489 | version of this manual in the @file{gdb} subdirectory. The main Info | |
14490 | file is @file{gdb-@value{GDBVN}/gdb/gdb.info}, and it refers to | |
14491 | subordinate files matching @samp{gdb.info*} in the same directory. If | |
14492 | necessary, you can print out these files, or read them with any editor; | |
14493 | but they are easier to read using the @code{info} subsystem in @sc{gnu} | |
14494 | Emacs or the standalone @code{info} program, available as part of the | |
14495 | @sc{gnu} Texinfo distribution. | |
14496 | ||
14497 | If you want to format these Info files yourself, you need one of the | |
14498 | Info formatting programs, such as @code{texinfo-format-buffer} or | |
14499 | @code{makeinfo}. | |
14500 | ||
14501 | If you have @code{makeinfo} installed, and are in the top level | |
14502 | @value{GDBN} source directory (@file{gdb-@value{GDBVN}}, in the case of | |
14503 | version @value{GDBVN}), you can make the Info file by typing: | |
14504 | ||
14505 | @example | |
14506 | cd gdb | |
14507 | make gdb.info | |
14508 | @end example | |
14509 | ||
14510 | If you want to typeset and print copies of this manual, you need @TeX{}, | |
14511 | a program to print its @sc{dvi} output files, and @file{texinfo.tex}, the | |
14512 | Texinfo definitions file. | |
14513 | ||
14514 | @TeX{} is a typesetting program; it does not print files directly, but | |
14515 | produces output files called @sc{dvi} files. To print a typeset | |
14516 | document, you need a program to print @sc{dvi} files. If your system | |
14517 | has @TeX{} installed, chances are it has such a program. The precise | |
14518 | command to use depends on your system; @kbd{lpr -d} is common; another | |
14519 | (for PostScript devices) is @kbd{dvips}. The @sc{dvi} print command may | |
14520 | require a file name without any extension or a @samp{.dvi} extension. | |
14521 | ||
14522 | @TeX{} also requires a macro definitions file called | |
14523 | @file{texinfo.tex}. This file tells @TeX{} how to typeset a document | |
14524 | written in Texinfo format. On its own, @TeX{} cannot either read or | |
14525 | typeset a Texinfo file. @file{texinfo.tex} is distributed with GDB | |
14526 | and is located in the @file{gdb-@var{version-number}/texinfo} | |
14527 | directory. | |
14528 | ||
14529 | If you have @TeX{} and a @sc{dvi} printer program installed, you can | |
14530 | typeset and print this manual. First switch to the the @file{gdb} | |
14531 | subdirectory of the main source directory (for example, to | |
14532 | @file{gdb-@value{GDBVN}/gdb}) and type: | |
14533 | ||
14534 | @example | |
14535 | make gdb.dvi | |
14536 | @end example | |
14537 | ||
14538 | Then give @file{gdb.dvi} to your @sc{dvi} printing program. | |
c906108c | 14539 | |
6d2ebf8b | 14540 | @node Installing GDB |
c906108c SS |
14541 | @appendix Installing @value{GDBN} |
14542 | @cindex configuring @value{GDBN} | |
14543 | @cindex installation | |
14544 | ||
c906108c SS |
14545 | @value{GDBN} comes with a @code{configure} script that automates the process |
14546 | of preparing @value{GDBN} for installation; you can then use @code{make} to | |
14547 | build the @code{gdb} program. | |
14548 | @iftex | |
14549 | @c irrelevant in info file; it's as current as the code it lives with. | |
14550 | @footnote{If you have a more recent version of @value{GDBN} than @value{GDBVN}, | |
14551 | look at the @file{README} file in the sources; we may have improved the | |
14552 | installation procedures since publishing this manual.} | |
14553 | @end iftex | |
14554 | ||
5d161b24 DB |
14555 | The @value{GDBN} distribution includes all the source code you need for |
14556 | @value{GDBN} in a single directory, whose name is usually composed by | |
c906108c SS |
14557 | appending the version number to @samp{gdb}. |
14558 | ||
14559 | For example, the @value{GDBN} version @value{GDBVN} distribution is in the | |
14560 | @file{gdb-@value{GDBVN}} directory. That directory contains: | |
14561 | ||
14562 | @table @code | |
14563 | @item gdb-@value{GDBVN}/configure @r{(and supporting files)} | |
14564 | script for configuring @value{GDBN} and all its supporting libraries | |
14565 | ||
14566 | @item gdb-@value{GDBVN}/gdb | |
14567 | the source specific to @value{GDBN} itself | |
14568 | ||
14569 | @item gdb-@value{GDBVN}/bfd | |
14570 | source for the Binary File Descriptor library | |
14571 | ||
14572 | @item gdb-@value{GDBVN}/include | |
14573 | @sc{gnu} include files | |
14574 | ||
14575 | @item gdb-@value{GDBVN}/libiberty | |
14576 | source for the @samp{-liberty} free software library | |
14577 | ||
14578 | @item gdb-@value{GDBVN}/opcodes | |
14579 | source for the library of opcode tables and disassemblers | |
14580 | ||
14581 | @item gdb-@value{GDBVN}/readline | |
14582 | source for the @sc{gnu} command-line interface | |
14583 | ||
14584 | @item gdb-@value{GDBVN}/glob | |
14585 | source for the @sc{gnu} filename pattern-matching subroutine | |
14586 | ||
14587 | @item gdb-@value{GDBVN}/mmalloc | |
14588 | source for the @sc{gnu} memory-mapped malloc package | |
14589 | @end table | |
14590 | ||
14591 | The simplest way to configure and build @value{GDBN} is to run @code{configure} | |
14592 | from the @file{gdb-@var{version-number}} source directory, which in | |
14593 | this example is the @file{gdb-@value{GDBVN}} directory. | |
14594 | ||
14595 | First switch to the @file{gdb-@var{version-number}} source directory | |
14596 | if you are not already in it; then run @code{configure}. Pass the | |
14597 | identifier for the platform on which @value{GDBN} will run as an | |
14598 | argument. | |
14599 | ||
14600 | For example: | |
14601 | ||
14602 | @example | |
14603 | cd gdb-@value{GDBVN} | |
14604 | ./configure @var{host} | |
14605 | make | |
14606 | @end example | |
14607 | ||
14608 | @noindent | |
14609 | where @var{host} is an identifier such as @samp{sun4} or | |
14610 | @samp{decstation}, that identifies the platform where @value{GDBN} will run. | |
14611 | (You can often leave off @var{host}; @code{configure} tries to guess the | |
14612 | correct value by examining your system.) | |
14613 | ||
14614 | Running @samp{configure @var{host}} and then running @code{make} builds the | |
14615 | @file{bfd}, @file{readline}, @file{mmalloc}, and @file{libiberty} | |
14616 | libraries, then @code{gdb} itself. The configured source files, and the | |
14617 | binaries, are left in the corresponding source directories. | |
14618 | ||
14619 | @need 750 | |
14620 | @code{configure} is a Bourne-shell (@code{/bin/sh}) script; if your | |
14621 | system does not recognize this automatically when you run a different | |
14622 | shell, you may need to run @code{sh} on it explicitly: | |
14623 | ||
14624 | @example | |
14625 | sh configure @var{host} | |
14626 | @end example | |
14627 | ||
14628 | If you run @code{configure} from a directory that contains source | |
14629 | directories for multiple libraries or programs, such as the | |
14630 | @file{gdb-@value{GDBVN}} source directory for version @value{GDBVN}, @code{configure} | |
14631 | creates configuration files for every directory level underneath (unless | |
14632 | you tell it not to, with the @samp{--norecursion} option). | |
14633 | ||
14634 | You can run the @code{configure} script from any of the | |
14635 | subordinate directories in the @value{GDBN} distribution if you only want to | |
14636 | configure that subdirectory, but be sure to specify a path to it. | |
14637 | ||
14638 | For example, with version @value{GDBVN}, type the following to configure only | |
14639 | the @code{bfd} subdirectory: | |
14640 | ||
14641 | @example | |
14642 | @group | |
14643 | cd gdb-@value{GDBVN}/bfd | |
14644 | ../configure @var{host} | |
14645 | @end group | |
14646 | @end example | |
14647 | ||
14648 | You can install @code{@value{GDBP}} anywhere; it has no hardwired paths. | |
14649 | However, you should make sure that the shell on your path (named by | |
14650 | the @samp{SHELL} environment variable) is publicly readable. Remember | |
14651 | that @value{GDBN} uses the shell to start your program---some systems refuse to | |
14652 | let @value{GDBN} debug child processes whose programs are not readable. | |
14653 | ||
14654 | @menu | |
14655 | * Separate Objdir:: Compiling @value{GDBN} in another directory | |
14656 | * Config Names:: Specifying names for hosts and targets | |
14657 | * Configure Options:: Summary of options for configure | |
14658 | @end menu | |
14659 | ||
6d2ebf8b | 14660 | @node Separate Objdir |
c906108c SS |
14661 | @section Compiling @value{GDBN} in another directory |
14662 | ||
14663 | If you want to run @value{GDBN} versions for several host or target machines, | |
14664 | you need a different @code{gdb} compiled for each combination of | |
14665 | host and target. @code{configure} is designed to make this easy by | |
14666 | allowing you to generate each configuration in a separate subdirectory, | |
14667 | rather than in the source directory. If your @code{make} program | |
14668 | handles the @samp{VPATH} feature (@sc{gnu} @code{make} does), running | |
14669 | @code{make} in each of these directories builds the @code{gdb} | |
14670 | program specified there. | |
14671 | ||
14672 | To build @code{gdb} in a separate directory, run @code{configure} | |
14673 | with the @samp{--srcdir} option to specify where to find the source. | |
14674 | (You also need to specify a path to find @code{configure} | |
14675 | itself from your working directory. If the path to @code{configure} | |
14676 | would be the same as the argument to @samp{--srcdir}, you can leave out | |
14677 | the @samp{--srcdir} option; it is assumed.) | |
14678 | ||
5d161b24 | 14679 | For example, with version @value{GDBVN}, you can build @value{GDBN} in a |
c906108c SS |
14680 | separate directory for a Sun 4 like this: |
14681 | ||
14682 | @example | |
14683 | @group | |
14684 | cd gdb-@value{GDBVN} | |
14685 | mkdir ../gdb-sun4 | |
14686 | cd ../gdb-sun4 | |
14687 | ../gdb-@value{GDBVN}/configure sun4 | |
14688 | make | |
14689 | @end group | |
14690 | @end example | |
14691 | ||
14692 | When @code{configure} builds a configuration using a remote source | |
14693 | directory, it creates a tree for the binaries with the same structure | |
14694 | (and using the same names) as the tree under the source directory. In | |
14695 | the example, you'd find the Sun 4 library @file{libiberty.a} in the | |
14696 | directory @file{gdb-sun4/libiberty}, and @value{GDBN} itself in | |
14697 | @file{gdb-sun4/gdb}. | |
14698 | ||
14699 | One popular reason to build several @value{GDBN} configurations in separate | |
5d161b24 DB |
14700 | directories is to configure @value{GDBN} for cross-compiling (where |
14701 | @value{GDBN} runs on one machine---the @dfn{host}---while debugging | |
14702 | programs that run on another machine---the @dfn{target}). | |
c906108c SS |
14703 | You specify a cross-debugging target by |
14704 | giving the @samp{--target=@var{target}} option to @code{configure}. | |
14705 | ||
14706 | When you run @code{make} to build a program or library, you must run | |
14707 | it in a configured directory---whatever directory you were in when you | |
14708 | called @code{configure} (or one of its subdirectories). | |
14709 | ||
14710 | The @code{Makefile} that @code{configure} generates in each source | |
14711 | directory also runs recursively. If you type @code{make} in a source | |
14712 | directory such as @file{gdb-@value{GDBVN}} (or in a separate configured | |
14713 | directory configured with @samp{--srcdir=@var{dirname}/gdb-@value{GDBVN}}), you | |
14714 | will build all the required libraries, and then build GDB. | |
14715 | ||
14716 | When you have multiple hosts or targets configured in separate | |
14717 | directories, you can run @code{make} on them in parallel (for example, | |
14718 | if they are NFS-mounted on each of the hosts); they will not interfere | |
14719 | with each other. | |
14720 | ||
6d2ebf8b | 14721 | @node Config Names |
c906108c SS |
14722 | @section Specifying names for hosts and targets |
14723 | ||
14724 | The specifications used for hosts and targets in the @code{configure} | |
14725 | script are based on a three-part naming scheme, but some short predefined | |
14726 | aliases are also supported. The full naming scheme encodes three pieces | |
14727 | of information in the following pattern: | |
14728 | ||
14729 | @example | |
14730 | @var{architecture}-@var{vendor}-@var{os} | |
14731 | @end example | |
14732 | ||
14733 | For example, you can use the alias @code{sun4} as a @var{host} argument, | |
14734 | or as the value for @var{target} in a @code{--target=@var{target}} | |
14735 | option. The equivalent full name is @samp{sparc-sun-sunos4}. | |
14736 | ||
14737 | The @code{configure} script accompanying @value{GDBN} does not provide | |
14738 | any query facility to list all supported host and target names or | |
14739 | aliases. @code{configure} calls the Bourne shell script | |
14740 | @code{config.sub} to map abbreviations to full names; you can read the | |
14741 | script, if you wish, or you can use it to test your guesses on | |
14742 | abbreviations---for example: | |
14743 | ||
14744 | @smallexample | |
14745 | % sh config.sub i386-linux | |
14746 | i386-pc-linux-gnu | |
14747 | % sh config.sub alpha-linux | |
14748 | alpha-unknown-linux-gnu | |
14749 | % sh config.sub hp9k700 | |
14750 | hppa1.1-hp-hpux | |
14751 | % sh config.sub sun4 | |
14752 | sparc-sun-sunos4.1.1 | |
14753 | % sh config.sub sun3 | |
14754 | m68k-sun-sunos4.1.1 | |
14755 | % sh config.sub i986v | |
14756 | Invalid configuration `i986v': machine `i986v' not recognized | |
14757 | @end smallexample | |
14758 | ||
14759 | @noindent | |
14760 | @code{config.sub} is also distributed in the @value{GDBN} source | |
14761 | directory (@file{gdb-@value{GDBVN}}, for version @value{GDBVN}). | |
14762 | ||
6d2ebf8b | 14763 | @node Configure Options |
c906108c SS |
14764 | @section @code{configure} options |
14765 | ||
14766 | Here is a summary of the @code{configure} options and arguments that | |
14767 | are most often useful for building @value{GDBN}. @code{configure} also has | |
14768 | several other options not listed here. @inforef{What Configure | |
14769 | Does,,configure.info}, for a full explanation of @code{configure}. | |
14770 | ||
14771 | @example | |
14772 | configure @r{[}--help@r{]} | |
14773 | @r{[}--prefix=@var{dir}@r{]} | |
14774 | @r{[}--exec-prefix=@var{dir}@r{]} | |
14775 | @r{[}--srcdir=@var{dirname}@r{]} | |
14776 | @r{[}--norecursion@r{]} @r{[}--rm@r{]} | |
14777 | @r{[}--target=@var{target}@r{]} | |
14778 | @var{host} | |
14779 | @end example | |
14780 | ||
14781 | @noindent | |
14782 | You may introduce options with a single @samp{-} rather than | |
14783 | @samp{--} if you prefer; but you may abbreviate option names if you use | |
14784 | @samp{--}. | |
14785 | ||
14786 | @table @code | |
14787 | @item --help | |
14788 | Display a quick summary of how to invoke @code{configure}. | |
14789 | ||
14790 | @item --prefix=@var{dir} | |
14791 | Configure the source to install programs and files under directory | |
14792 | @file{@var{dir}}. | |
14793 | ||
14794 | @item --exec-prefix=@var{dir} | |
14795 | Configure the source to install programs under directory | |
14796 | @file{@var{dir}}. | |
14797 | ||
14798 | @c avoid splitting the warning from the explanation: | |
14799 | @need 2000 | |
14800 | @item --srcdir=@var{dirname} | |
14801 | @strong{Warning: using this option requires @sc{gnu} @code{make}, or another | |
14802 | @code{make} that implements the @code{VPATH} feature.}@* | |
14803 | Use this option to make configurations in directories separate from the | |
14804 | @value{GDBN} source directories. Among other things, you can use this to | |
14805 | build (or maintain) several configurations simultaneously, in separate | |
14806 | directories. @code{configure} writes configuration specific files in | |
14807 | the current directory, but arranges for them to use the source in the | |
14808 | directory @var{dirname}. @code{configure} creates directories under | |
14809 | the working directory in parallel to the source directories below | |
14810 | @var{dirname}. | |
14811 | ||
14812 | @item --norecursion | |
14813 | Configure only the directory level where @code{configure} is executed; do not | |
14814 | propagate configuration to subdirectories. | |
14815 | ||
14816 | @item --target=@var{target} | |
14817 | Configure @value{GDBN} for cross-debugging programs running on the specified | |
14818 | @var{target}. Without this option, @value{GDBN} is configured to debug | |
14819 | programs that run on the same machine (@var{host}) as @value{GDBN} itself. | |
14820 | ||
14821 | There is no convenient way to generate a list of all available targets. | |
14822 | ||
14823 | @item @var{host} @dots{} | |
14824 | Configure @value{GDBN} to run on the specified @var{host}. | |
14825 | ||
14826 | There is no convenient way to generate a list of all available hosts. | |
14827 | @end table | |
14828 | ||
14829 | There are many other options available as well, but they are generally | |
14830 | needed for special purposes only. | |
5d161b24 | 14831 | |
eb12ee30 AC |
14832 | @node Maintenance Commands |
14833 | @appendix Maintenance Commands | |
14834 | @cindex maintenance commands | |
14835 | @cindex internal commands | |
14836 | ||
14837 | In addition to commands intended for @value{GDBN} users, @value{GDBN} | |
14838 | includes a number of commands intended for @value{GDBN} developers. | |
14839 | These commands are provided here for reference. | |
14840 | ||
14841 | @table @code | |
14842 | @kindex maint info breakpoints | |
14843 | @item @anchor{maint info breakpoints}maint info breakpoints | |
14844 | Using the same format as @samp{info breakpoints}, display both the | |
14845 | breakpoints you've set explicitly, and those @value{GDBN} is using for | |
14846 | internal purposes. Internal breakpoints are shown with negative | |
14847 | breakpoint numbers. The type column identifies what kind of breakpoint | |
14848 | is shown: | |
14849 | ||
14850 | @table @code | |
14851 | @item breakpoint | |
14852 | Normal, explicitly set breakpoint. | |
14853 | ||
14854 | @item watchpoint | |
14855 | Normal, explicitly set watchpoint. | |
14856 | ||
14857 | @item longjmp | |
14858 | Internal breakpoint, used to handle correctly stepping through | |
14859 | @code{longjmp} calls. | |
14860 | ||
14861 | @item longjmp resume | |
14862 | Internal breakpoint at the target of a @code{longjmp}. | |
14863 | ||
14864 | @item until | |
14865 | Temporary internal breakpoint used by the @value{GDBN} @code{until} command. | |
14866 | ||
14867 | @item finish | |
14868 | Temporary internal breakpoint used by the @value{GDBN} @code{finish} command. | |
14869 | ||
14870 | @item shlib events | |
14871 | Shared library events. | |
14872 | ||
14873 | @end table | |
14874 | ||
14875 | @end table | |
14876 | ||
6826cf00 EZ |
14877 | @include fdl.texi |
14878 | ||
6d2ebf8b | 14879 | @node Index |
c906108c SS |
14880 | @unnumbered Index |
14881 | ||
14882 | @printindex cp | |
14883 | ||
14884 | @tex | |
14885 | % I think something like @colophon should be in texinfo. In the | |
14886 | % meantime: | |
14887 | \long\def\colophon{\hbox to0pt{}\vfill | |
14888 | \centerline{The body of this manual is set in} | |
14889 | \centerline{\fontname\tenrm,} | |
14890 | \centerline{with headings in {\bf\fontname\tenbf}} | |
14891 | \centerline{and examples in {\tt\fontname\tentt}.} | |
14892 | \centerline{{\it\fontname\tenit\/},} | |
14893 | \centerline{{\bf\fontname\tenbf}, and} | |
14894 | \centerline{{\sl\fontname\tensl\/}} | |
14895 | \centerline{are used for emphasis.}\vfill} | |
14896 | \page\colophon | |
14897 | % Blame: doc@cygnus.com, 1991. | |
14898 | @end tex | |
14899 | ||
449f3b6c AC |
14900 | @c TeX can handle the contents at the start but makeinfo 3.12 can not |
14901 | @ifinfo | |
c906108c | 14902 | @contents |
449f3b6c AC |
14903 | @end ifinfo |
14904 | @ifhtml | |
14905 | @contents | |
14906 | @end ifhtml | |
14907 | ||
c906108c | 14908 | @bye |