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29a2b744 | 1 | \input texinfo @c -*-texinfo-*- |
ed447b95 | 2 | @c Copyright (c) 1988 1989 1990 1991 1992 1993 Free Software Foundation, Inc. |
18fae2a8 | 3 | @c |
29a2b744 | 4 | @c %**start of header |
18fae2a8 RP |
5 | @c makeinfo ignores cmds prev to setfilename, so its arg cannot make use |
6 | @c of @set vars. However, we can override filename with makeinfo -o. | |
7 | @setfilename gdb.info | |
8 | @c | |
9 | @include gdb-config.texi | |
10 | @c | |
11 | @ifset GENERIC | |
12 | @settitle Debugging with @value{GDBN} | |
13 | @end ifset | |
14 | @ifclear GENERIC | |
15 | @settitle Debugging with @value{GDBN} (@value{HOST}) | |
16 | @end ifclear | |
29a2b744 | 17 | @setchapternewpage odd |
29a2b744 RP |
18 | @c %**end of header |
19 | ||
ed447b95 RP |
20 | @iftex |
21 | @c smallbook | |
22 | @c cropmarks | |
23 | @end iftex | |
24 | ||
25 | @c Include the readline documentation in the TeX output, | |
26 | @c but not in the Info output. | |
27 | @c Eventually, we should make a cross reference to the Readline Info | |
28 | @c nodes; but this requires that the nodes exist and be in an expected | |
29 | @c place. Wait for a standard, complete GNU distribution. Meanwhile, | |
30 | @c cross references are only in the printed TeX output, and only when | |
31 | @c `have-readline-appendices' is set. | |
32 | @c | |
33 | @c The readline documentation is distributed with the readline code | |
34 | @c and consists of the two following files: | |
35 | @c rluser.texinfo | |
36 | @c inc-hist.texi | |
37 | @iftex | |
38 | @set have-readline-appendices | |
39 | @end iftex | |
40 | @ifinfo | |
41 | @clear have-readline-appendices | |
42 | @end ifinfo | |
43 | ||
29a2b744 RP |
44 | @finalout |
45 | @syncodeindex ky cp | |
46 | ||
18fae2a8 | 47 | @c ===> NOTE! <== |
29a2b744 RP |
48 | @c Determine the edition number in *three* places by hand: |
49 | @c 1. First ifinfo section 2. title page 3. top node | |
50 | @c To find the locations, search for !!set | |
51 | ||
d24e0922 | 52 | @c GDB CHANGELOG CONSULTED BETWEEN: |
29a2b744 RP |
53 | @c Fri Oct 11 23:27:06 1991 John Gilmore (gnu at cygnus.com) |
54 | @c Sat Dec 22 02:51:40 1990 John Gilmore (gnu at cygint) | |
55 | ||
9c3ad547 | 56 | @c THIS MANUAL REQUIRES TEXINFO-2 macros and info-makers to format properly. |
29a2b744 | 57 | |
b7becc8f | 58 | @ifinfo |
ed447b95 RP |
59 | @c This is a dir.info fragment to support semi-automated addition of |
60 | @c manuals to an info tree. zoo@cygnus.com is developing this facility. | |
b7becc8f RP |
61 | @format |
62 | START-INFO-DIR-ENTRY | |
29a2b744 | 63 | * Gdb: (gdb). The GNU debugger. |
b7becc8f RP |
64 | END-INFO-DIR-ENTRY |
65 | @end format | |
66 | @end ifinfo | |
18fae2a8 | 67 | @c |
70b88761 | 68 | @c |
70b88761 | 69 | @ifinfo |
18fae2a8 | 70 | This file documents the GNU debugger @value{GDBN}. |
70b88761 | 71 | |
29a2b744 | 72 | @c !!set edition, date, version |
ed447b95 | 73 | This is Edition 4.07, January 1993, |
18fae2a8 RP |
74 | of @cite{Debugging with @value{GDBN}: the GNU Source-Level Debugger} |
75 | for GDB Version @value{GDBVN}. | |
29a2b744 | 76 | |
ed447b95 | 77 | Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc. |
70b88761 RP |
78 | |
79 | Permission is granted to make and distribute verbatim copies of | |
80 | this manual provided the copyright notice and this permission notice | |
81 | are preserved on all copies. | |
82 | ||
83 | @ignore | |
84 | Permission is granted to process this file through TeX and print the | |
85 | results, provided the printed document carries copying permission | |
86 | notice identical to this one except for the removal of this paragraph | |
87 | (this paragraph not being relevant to the printed manual). | |
88 | ||
89 | @end ignore | |
90 | Permission is granted to copy and distribute modified versions of this | |
91 | manual under the conditions for verbatim copying, provided also that the | |
92 | section entitled ``GNU General Public License'' is included exactly as | |
93 | in the original, and provided that the entire resulting derived work is | |
94 | distributed under the terms of a permission notice identical to this | |
95 | one. | |
96 | ||
97 | Permission is granted to copy and distribute translations of this manual | |
98 | into another language, under the above conditions for modified versions, | |
99 | except that the section entitled ``GNU General Public License'' may be | |
100 | included in a translation approved by the Free Software Foundation | |
101 | instead of in the original English. | |
102 | @end ifinfo | |
1041a570 | 103 | |
70b88761 | 104 | @titlepage |
18fae2a8 | 105 | @title Debugging with @value{GDBN} |
95d5ceb9 | 106 | @subtitle The GNU Source-Level Debugger |
18fae2a8 RP |
107 | @ifclear GENERIC |
108 | @subtitle on @value{HOST} Systems | |
109 | @end ifclear | |
70b88761 | 110 | @sp 1 |
29a2b744 | 111 | @c !!set edition, date, version |
ed447b95 RP |
112 | @subtitle Edition 4.07, for @value{GDBN} version @value{GDBVN} |
113 | @subtitle January 1993 | |
29a2b744 | 114 | @author by Richard M. Stallman and Roland H. Pesch |
70b88761 RP |
115 | @page |
116 | @tex | |
117 | {\parskip=0pt | |
18fae2a8 | 118 | \hfill (Send bugs and comments on @value{GDBN} to bug-gdb\@prep.ai.mit.edu.)\par |
ed447b95 | 119 | \hfill {\it Debugging with @value{GDBN}}\par |
70b88761 | 120 | \hfill \TeX{}info \texinfoversion\par |
ed447b95 | 121 | \hfill pesch\@cygnus.com\par |
70b88761 RP |
122 | } |
123 | @end tex | |
124 | ||
125 | @vskip 0pt plus 1filll | |
ed447b95 | 126 | Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc. |
70b88761 RP |
127 | |
128 | Permission is granted to make and distribute verbatim copies of | |
129 | this manual provided the copyright notice and this permission notice | |
130 | are preserved on all copies. | |
131 | ||
132 | Permission is granted to copy and distribute modified versions of this | |
133 | manual under the conditions for verbatim copying, provided also that the | |
134 | section entitled ``GNU General Public License'' is included exactly as | |
135 | in the original, and provided that the entire resulting derived work is | |
136 | distributed under the terms of a permission notice identical to this | |
137 | one. | |
138 | ||
139 | Permission is granted to copy and distribute translations of this manual | |
140 | into another language, under the above conditions for modified versions, | |
141 | except that the section entitled ``GNU General Public License'' may be | |
142 | included in a translation approved by the Free Software Foundation | |
143 | instead of in the original English. | |
144 | @end titlepage | |
145 | @page | |
146 | ||
70b88761 | 147 | @ifinfo |
4eb4cf57 | 148 | @node Top |
18fae2a8 | 149 | @top Debugging with @value{GDBN} |
29a2b744 | 150 | |
18fae2a8 | 151 | This file describes @value{GDBN}, the GNU symbolic debugger. |
29a2b744 RP |
152 | |
153 | @c !!set edition, date, version | |
ed447b95 | 154 | This is Edition 4.07, January 1993, for GDB Version @value{GDBVN}. |
70b88761 | 155 | |
18fae2a8 RP |
156 | @c Makeinfo node defaulting gets very confused by conditionals in menus, |
157 | @c unfortunately. Otherwise we would use the following ignored menu, | |
158 | @c which involves four switches: | |
159 | @ignore | |
70b88761 | 160 | @menu |
18fae2a8 RP |
161 | * Summary:: Summary of @value{GDBN} |
162 | @ifset NOVEL | |
c7cb8acb | 163 | * New Features:: New features since GDB version 3.5 |
18fae2a8 RP |
164 | @end ifset |
165 | @ifclear BARETARGET | |
166 | * Sample Session:: A sample @value{GDBN} session | |
167 | @end ifclear | |
168 | * Invocation:: Getting in and out of @value{GDBN} | |
169 | * Commands:: @value{GDBN} commands | |
170 | * Running:: Running programs under @value{GDBN} | |
29a2b744 RP |
171 | * Stopping:: Stopping and continuing |
172 | * Stack:: Examining the stack | |
173 | * Source:: Examining source files | |
174 | * Data:: Examining data | |
18fae2a8 RP |
175 | @ifclear CONLY |
176 | * Languages:: Using @value{GDBN} with different languages | |
177 | @end ifclear | |
178 | @ifset CONLY | |
4eb4cf57 | 179 | * C:: C and C++ |
18fae2a8 RP |
180 | @end ifset |
181 | * Symbols:: Examining the symbol table | |
182 | * Altering:: Altering execution | |
183 | * GDB Files:: @value{GDBN}'s files | |
184 | * Targets:: Specifying a debugging target | |
185 | * Controlling GDB:: Controlling @value{GDBN} | |
186 | * Sequences:: Canned sequences of commands | |
187 | @ifclear DOSHOST | |
188 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
189 | @end ifclear | |
190 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
191 | @ifset NOVEL | |
192 | * Renamed Commands:: | |
193 | @end ifset | |
194 | * Formatting Documentation:: How to format and print GDB documentation | |
195 | * Installing GDB:: Installing GDB | |
196 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
197 | * Index:: Index | |
198 | @end menu | |
199 | @end ignore | |
200 | @c | |
201 | @c Since that doesn't work, we must unroll the above into 16 cases: | |
202 | @c | |
203 | @c Menu for NOVEL && !BARETARGET && !CONLY && !DOSHOST | |
204 | @ifset NOVEL | |
205 | @ifclear BARETARGET | |
206 | @ifclear CONLY | |
207 | @ifclear DOSHOST | |
208 | @menu | |
209 | * Summary:: Summary of @value{GDBN} | |
210 | * New Features:: New features since GDB version 3.5 | |
211 | * Sample Session:: A sample @value{GDBN} session | |
212 | * Invocation:: Getting in and out of @value{GDBN} | |
213 | * Commands:: @value{GDBN} commands | |
214 | * Running:: Running programs under @value{GDBN} | |
215 | * Stopping:: Stopping and continuing | |
216 | * Stack:: Examining the stack | |
217 | * Source:: Examining source files | |
218 | * Data:: Examining data | |
219 | * Languages:: Using @value{GDBN} with different languages | |
220 | * Symbols:: Examining the symbol table | |
221 | * Altering:: Altering execution | |
222 | * GDB Files:: @value{GDBN}'s files | |
223 | * Targets:: Specifying a debugging target | |
224 | * Controlling GDB:: Controlling @value{GDBN} | |
225 | * Sequences:: Canned sequences of commands | |
226 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
227 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
228 | * Renamed Commands:: | |
229 | * Formatting Documentation:: How to format and print GDB documentation | |
230 | * Installing GDB:: Installing GDB | |
231 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
232 | * Index:: Index | |
233 | @end menu | |
234 | @end ifclear | |
235 | @end ifclear | |
236 | @end ifclear | |
237 | @end ifset | |
238 | ||
239 | @c Menu for NOVEL && !BARETARGET && !CONLY && DOSHOST | |
240 | @ifset NOVEL | |
241 | @ifclear BARETARGET | |
242 | @ifclear CONLY | |
243 | @ifset DOSHOST | |
244 | @menu | |
245 | * Summary:: Summary of @value{GDBN} | |
246 | * New Features:: New features since GDB version 3.5 | |
247 | * Sample Session:: A sample @value{GDBN} session | |
248 | * Invocation:: Getting in and out of @value{GDBN} | |
249 | * Commands:: @value{GDBN} commands | |
250 | * Running:: Running programs under @value{GDBN} | |
251 | * Stopping:: Stopping and continuing | |
252 | * Stack:: Examining the stack | |
253 | * Source:: Examining source files | |
254 | * Data:: Examining data | |
255 | * Languages:: Using @value{GDBN} with different languages | |
256 | * Symbols:: Examining the symbol table | |
257 | * Altering:: Altering execution | |
258 | * GDB Files:: @value{GDBN}'s files | |
259 | * Targets:: Specifying a debugging target | |
260 | * Controlling GDB:: Controlling @value{GDBN} | |
261 | * Sequences:: Canned sequences of commands | |
262 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
263 | * Renamed Commands:: | |
264 | * Formatting Documentation:: How to format and print GDB documentation | |
265 | * Installing GDB:: Installing GDB | |
266 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
267 | * Index:: Index | |
268 | @end menu | |
269 | @end ifset | |
270 | @end ifclear | |
271 | @end ifclear | |
272 | @end ifset | |
273 | ||
274 | @c Menu for NOVEL && !BARETARGET && CONLY && !DOSHOST | |
275 | @ifset NOVEL | |
276 | @ifclear BARETARGET | |
277 | @ifset CONLY | |
278 | @ifclear DOSHOST | |
279 | @menu | |
280 | * Summary:: Summary of @value{GDBN} | |
281 | * New Features:: New features since GDB version 3.5 | |
282 | * Sample Session:: A sample @value{GDBN} session | |
283 | * Invocation:: Getting in and out of @value{GDBN} | |
284 | * Commands:: @value{GDBN} commands | |
285 | * Running:: Running programs under @value{GDBN} | |
286 | * Stopping:: Stopping and continuing | |
287 | * Stack:: Examining the stack | |
288 | * Source:: Examining source files | |
289 | * Data:: Examining data | |
290 | * C:: C Language Support | |
291 | * Symbols:: Examining the symbol table | |
292 | * Altering:: Altering execution | |
293 | * GDB Files:: @value{GDBN}'s files | |
294 | * Targets:: Specifying a debugging target | |
295 | * Controlling GDB:: Controlling @value{GDBN} | |
296 | * Sequences:: Canned sequences of commands | |
297 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
298 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
299 | * Renamed Commands:: | |
300 | * Formatting Documentation:: How to format and print GDB documentation | |
301 | * Installing GDB:: Installing GDB | |
302 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
303 | * Index:: Index | |
304 | @end menu | |
305 | @end ifclear | |
306 | @end ifset | |
307 | @end ifclear | |
308 | @end ifset | |
309 | ||
310 | @c Menu for NOVEL && !BARETARGET && CONLY && DOSHOST | |
311 | @ifset NOVEL | |
312 | @ifclear BARETARGET | |
313 | @ifset CONLY | |
314 | @ifset DOSHOST | |
315 | @menu | |
316 | * Summary:: Summary of @value{GDBN} | |
317 | * New Features:: New features since GDB version 3.5 | |
318 | * Sample Session:: A sample @value{GDBN} session | |
319 | * Invocation:: Getting in and out of @value{GDBN} | |
320 | * Commands:: @value{GDBN} commands | |
321 | * Running:: Running programs under @value{GDBN} | |
322 | * Stopping:: Stopping and continuing | |
323 | * Stack:: Examining the stack | |
324 | * Source:: Examining source files | |
325 | * Data:: Examining data | |
326 | * C:: C Language Support | |
327 | * Symbols:: Examining the symbol table | |
328 | * Altering:: Altering execution | |
329 | * GDB Files:: @value{GDBN}'s files | |
330 | * Targets:: Specifying a debugging target | |
331 | * Controlling GDB:: Controlling @value{GDBN} | |
332 | * Sequences:: Canned sequences of commands | |
333 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
334 | * Renamed Commands:: | |
335 | * Formatting Documentation:: How to format and print GDB documentation | |
336 | * Installing GDB:: Installing GDB | |
337 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
338 | * Index:: Index | |
339 | @end menu | |
340 | @end ifset | |
341 | @end ifset | |
342 | @end ifclear | |
343 | @end ifset | |
344 | ||
345 | @c Menu for NOVEL && BARETARGET && !CONLY && !DOSHOST | |
346 | @ifset NOVEL | |
347 | @ifset BARETARGET | |
348 | @ifclear CONLY | |
349 | @ifclear DOSHOST | |
350 | @menu | |
351 | * Summary:: Summary of @value{GDBN} | |
352 | * New Features:: New features since GDB version 3.5 | |
353 | * Invocation:: Getting in and out of @value{GDBN} | |
354 | * Commands:: @value{GDBN} commands | |
355 | * Running:: Running programs under @value{GDBN} | |
356 | * Stopping:: Stopping and continuing | |
357 | * Stack:: Examining the stack | |
358 | * Source:: Examining source files | |
359 | * Data:: Examining data | |
360 | * Languages:: Using @value{GDBN} with different languages | |
361 | * Symbols:: Examining the symbol table | |
362 | * Altering:: Altering execution | |
363 | * GDB Files:: @value{GDBN}'s files | |
364 | * Targets:: Specifying a debugging target | |
365 | * Controlling GDB:: Controlling @value{GDBN} | |
366 | * Sequences:: Canned sequences of commands | |
367 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
368 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
369 | * Renamed Commands:: | |
370 | * Formatting Documentation:: How to format and print GDB documentation | |
371 | * Installing GDB:: Installing GDB | |
372 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
373 | * Index:: Index | |
374 | @end menu | |
375 | @end ifclear | |
376 | @end ifclear | |
377 | @end ifset | |
378 | @end ifset | |
379 | ||
380 | @c Menu for NOVEL && BARETARGET && !CONLY && DOSHOST | |
381 | @ifset NOVEL | |
382 | @ifset BARETARGET | |
383 | @ifclear CONLY | |
384 | @ifset DOSHOST | |
385 | @menu | |
386 | * Summary:: Summary of @value{GDBN} | |
387 | * New Features:: New features since GDB version 3.5 | |
388 | * Invocation:: Getting in and out of @value{GDBN} | |
389 | * Commands:: @value{GDBN} commands | |
390 | * Running:: Running programs under @value{GDBN} | |
391 | * Stopping:: Stopping and continuing | |
392 | * Stack:: Examining the stack | |
393 | * Source:: Examining source files | |
394 | * Data:: Examining data | |
395 | * Languages:: Using @value{GDBN} with different languages | |
396 | * Symbols:: Examining the symbol table | |
397 | * Altering:: Altering execution | |
398 | * GDB Files:: @value{GDBN}'s files | |
399 | * Targets:: Specifying a debugging target | |
400 | * Controlling GDB:: Controlling @value{GDBN} | |
401 | * Sequences:: Canned sequences of commands | |
402 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
403 | * Renamed Commands:: | |
404 | * Formatting Documentation:: How to format and print GDB documentation | |
405 | * Installing GDB:: Installing GDB | |
406 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
407 | * Index:: Index | |
408 | @end menu | |
409 | @end ifset | |
410 | @end ifclear | |
411 | @end ifset | |
412 | @end ifset | |
413 | ||
414 | @c Menu for NOVEL && BARETARGET && CONLY && !DOSHOST | |
415 | @ifset NOVEL | |
416 | @ifset BARETARGET | |
417 | @ifset CONLY | |
418 | @ifclear DOSHOST | |
419 | @menu | |
420 | * Summary:: Summary of @value{GDBN} | |
421 | * New Features:: New features since GDB version 3.5 | |
422 | * Invocation:: Getting in and out of @value{GDBN} | |
423 | * Commands:: @value{GDBN} commands | |
424 | * Running:: Running programs under @value{GDBN} | |
425 | * Stopping:: Stopping and continuing | |
426 | * Stack:: Examining the stack | |
427 | * Source:: Examining source files | |
428 | * Data:: Examining data | |
429 | * C:: C Language support | |
29a2b744 RP |
430 | * Symbols:: Examining the symbol table |
431 | * Altering:: Altering execution | |
18fae2a8 | 432 | * GDB Files:: @value{GDBN}'s files |
29a2b744 | 433 | * Targets:: Specifying a debugging target |
18fae2a8 | 434 | * Controlling GDB:: Controlling @value{GDBN} |
29a2b744 | 435 | * Sequences:: Canned sequences of commands |
18fae2a8 RP |
436 | * Emacs:: Using @value{GDBN} under GNU Emacs |
437 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
e251e767 | 438 | * Renamed Commands:: |
77b46d13 | 439 | * Formatting Documentation:: How to format and print GDB documentation |
c7cb8acb | 440 | * Installing GDB:: Installing GDB |
b80282d5 RP |
441 | * Copying:: GNU GENERAL PUBLIC LICENSE |
442 | * Index:: Index | |
70b88761 | 443 | @end menu |
18fae2a8 RP |
444 | @end ifclear |
445 | @end ifset | |
446 | @end ifset | |
447 | @end ifset | |
448 | ||
449 | @c Menu for NOVEL && BARETARGET && CONLY && DOSHOST | |
450 | @ifset NOVEL | |
451 | @ifset BARETARGET | |
452 | @ifset CONLY | |
453 | @ifset DOSHOST | |
454 | @menu | |
455 | * Summary:: Summary of @value{GDBN} | |
456 | * New Features:: New features since GDB version 3.5 | |
457 | * Invocation:: Getting in and out of @value{GDBN} | |
458 | * Commands:: @value{GDBN} commands | |
459 | * Running:: Running programs under @value{GDBN} | |
460 | * Stopping:: Stopping and continuing | |
461 | * Stack:: Examining the stack | |
462 | * Source:: Examining source files | |
463 | * Data:: Examining data | |
464 | * C:: C Language support | |
465 | * Symbols:: Examining the symbol table | |
466 | * Altering:: Altering execution | |
467 | * GDB Files:: @value{GDBN}'s files | |
468 | * Targets:: Specifying a debugging target | |
469 | * Controlling GDB:: Controlling @value{GDBN} | |
470 | * Sequences:: Canned sequences of commands | |
471 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
472 | * Renamed Commands:: | |
473 | * Formatting Documentation:: How to format and print GDB documentation | |
474 | * Installing GDB:: Installing GDB | |
475 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
476 | * Index:: Index | |
477 | @end menu | |
478 | @end ifset | |
479 | @end ifset | |
480 | @end ifset | |
481 | @end ifset | |
482 | ||
483 | @c Menu for !NOVEL && !BARETARGET && !CONLY && !DOSHOST | |
484 | @ifclear NOVEL | |
485 | @ifclear BARETARGET | |
486 | @ifclear CONLY | |
487 | @ifclear DOSHOST | |
488 | @menu | |
489 | * Summary:: Summary of @value{GDBN} | |
490 | * Sample Session:: A sample @value{GDBN} session | |
491 | * Invocation:: Getting in and out of @value{GDBN} | |
492 | * Commands:: @value{GDBN} commands | |
493 | * Running:: Running programs under @value{GDBN} | |
494 | * Stopping:: Stopping and continuing | |
495 | * Stack:: Examining the stack | |
496 | * Source:: Examining source files | |
497 | * Data:: Examining data | |
498 | * Languages:: Using @value{GDBN} with different languages | |
499 | * Symbols:: Examining the symbol table | |
500 | * Altering:: Altering execution | |
501 | * GDB Files:: @value{GDBN}'s files | |
502 | * Targets:: Specifying a debugging target | |
503 | * Controlling GDB:: Controlling @value{GDBN} | |
504 | * Sequences:: Canned sequences of commands | |
505 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
506 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
507 | * Formatting Documentation:: How to format and print GDB documentation | |
508 | * Installing GDB:: Installing GDB | |
509 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
510 | * Index:: Index | |
511 | @end menu | |
512 | @end ifclear | |
513 | @end ifclear | |
514 | @end ifclear | |
515 | @end ifclear | |
516 | ||
517 | @c Menu for !NOVEL && !BARETARGET && !CONLY && DOSHOST | |
518 | @ifclear NOVEL | |
519 | @ifclear BARETARGET | |
520 | @ifclear CONLY | |
521 | @ifset DOSHOST | |
522 | @menu | |
523 | * Summary:: Summary of @value{GDBN} | |
524 | * Sample Session:: A sample @value{GDBN} session | |
525 | * Invocation:: Getting in and out of @value{GDBN} | |
526 | * Commands:: @value{GDBN} commands | |
527 | * Running:: Running programs under @value{GDBN} | |
528 | * Stopping:: Stopping and continuing | |
529 | * Stack:: Examining the stack | |
530 | * Source:: Examining source files | |
531 | * Data:: Examining data | |
532 | * Languages:: Using @value{GDBN} with different languages | |
533 | * Symbols:: Examining the symbol table | |
534 | * Altering:: Altering execution | |
535 | * GDB Files:: @value{GDBN}'s files | |
536 | * Targets:: Specifying a debugging target | |
537 | * Controlling GDB:: Controlling @value{GDBN} | |
538 | * Sequences:: Canned sequences of commands | |
539 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
540 | * Formatting Documentation:: How to format and print GDB documentation | |
541 | * Installing GDB:: Installing GDB | |
542 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
543 | * Index:: Index | |
544 | @end menu | |
545 | @end ifset | |
546 | @end ifclear | |
547 | @end ifclear | |
548 | @end ifclear | |
549 | ||
550 | @c Menu for !NOVEL && !BARETARGET && CONLY && !DOSHOST | |
551 | @ifclear NOVEL | |
552 | @ifclear BARETARGET | |
553 | @ifset CONLY | |
554 | @ifclear DOSHOST | |
555 | @menu | |
556 | * Summary:: Summary of @value{GDBN} | |
557 | * Sample Session:: A sample @value{GDBN} session | |
558 | * Invocation:: Getting in and out of @value{GDBN} | |
559 | * Commands:: @value{GDBN} commands | |
560 | * Running:: Running programs under @value{GDBN} | |
561 | * Stopping:: Stopping and continuing | |
562 | * Stack:: Examining the stack | |
563 | * Source:: Examining source files | |
564 | * Data:: Examining data | |
565 | * C:: C Language support | |
566 | * Symbols:: Examining the symbol table | |
567 | * Altering:: Altering execution | |
568 | * GDB Files:: @value{GDBN}'s files | |
569 | * Targets:: Specifying a debugging target | |
570 | * Controlling GDB:: Controlling @value{GDBN} | |
571 | * Sequences:: Canned sequences of commands | |
572 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
573 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
574 | * Formatting Documentation:: How to format and print GDB documentation | |
575 | * Installing GDB:: Installing GDB | |
576 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
577 | * Index:: Index | |
578 | @end menu | |
579 | @end ifclear | |
580 | @end ifset | |
581 | @end ifclear | |
582 | @end ifclear | |
583 | ||
584 | @c Menu for !NOVEL && !BARETARGET && CONLY && DOSHOST | |
585 | @ifclear NOVEL | |
586 | @ifclear BARETARGET | |
587 | @ifset CONLY | |
588 | @ifset DOSHOST | |
589 | @menu | |
590 | * Summary:: Summary of @value{GDBN} | |
591 | * Sample Session:: A sample @value{GDBN} session | |
592 | * Invocation:: Getting in and out of @value{GDBN} | |
593 | * Commands:: @value{GDBN} commands | |
594 | * Running:: Running programs under @value{GDBN} | |
595 | * Stopping:: Stopping and continuing | |
596 | * Stack:: Examining the stack | |
597 | * Source:: Examining source files | |
598 | * Data:: Examining data | |
599 | * C:: C Language support | |
600 | * Symbols:: Examining the symbol table | |
601 | * Altering:: Altering execution | |
602 | * GDB Files:: @value{GDBN}'s files | |
603 | * Targets:: Specifying a debugging target | |
604 | * Controlling GDB:: Controlling @value{GDBN} | |
605 | * Sequences:: Canned sequences of commands | |
606 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
607 | * Formatting Documentation:: How to format and print GDB documentation | |
608 | * Installing GDB:: Installing GDB | |
609 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
610 | * Index:: Index | |
611 | @end menu | |
612 | @end ifset | |
613 | @end ifset | |
614 | @end ifclear | |
615 | @end ifclear | |
616 | ||
617 | @c Menu for !NOVEL && BARETARGET && !CONLY && !DOSHOST | |
618 | @ifclear NOVEL | |
619 | @ifset BARETARGET | |
620 | @ifclear CONLY | |
621 | @ifclear DOSHOST | |
622 | @menu | |
623 | * Summary:: Summary of @value{GDBN} | |
624 | * Invocation:: Getting in and out of @value{GDBN} | |
625 | * Commands:: @value{GDBN} commands | |
626 | * Running:: Running programs under @value{GDBN} | |
627 | * Stopping:: Stopping and continuing | |
628 | * Stack:: Examining the stack | |
629 | * Source:: Examining source files | |
630 | * Data:: Examining data | |
631 | * Languages:: Using @value{GDBN} with different languages | |
632 | * Symbols:: Examining the symbol table | |
633 | * Altering:: Altering execution | |
634 | * GDB Files:: @value{GDBN}'s files | |
635 | * Targets:: Specifying a debugging target | |
636 | * Controlling GDB:: Controlling @value{GDBN} | |
637 | * Sequences:: Canned sequences of commands | |
638 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
639 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
640 | * Formatting Documentation:: How to format and print GDB documentation | |
641 | * Installing GDB:: Installing GDB | |
642 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
643 | * Index:: Index | |
644 | @end menu | |
645 | @end ifclear | |
646 | @end ifclear | |
647 | @end ifset | |
648 | @end ifclear | |
649 | ||
650 | @c Menu for !NOVEL && BARETARGET && !CONLY && DOSHOST | |
651 | @ifclear NOVEL | |
652 | @ifset BARETARGET | |
653 | @ifclear CONLY | |
654 | @ifset DOSHOST | |
655 | @menu | |
656 | * Summary:: Summary of @value{GDBN} | |
657 | * Invocation:: Getting in and out of @value{GDBN} | |
658 | * Commands:: @value{GDBN} commands | |
659 | * Running:: Running programs under @value{GDBN} | |
660 | * Stopping:: Stopping and continuing | |
661 | * Stack:: Examining the stack | |
662 | * Source:: Examining source files | |
663 | * Data:: Examining data | |
664 | * Languages:: Using @value{GDBN} with different languages | |
665 | * Symbols:: Examining the symbol table | |
666 | * Altering:: Altering execution | |
667 | * GDB Files:: @value{GDBN}'s files | |
668 | * Targets:: Specifying a debugging target | |
669 | * Controlling GDB:: Controlling @value{GDBN} | |
670 | * Sequences:: Canned sequences of commands | |
671 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
672 | * Formatting Documentation:: How to format and print GDB documentation | |
673 | * Installing GDB:: Installing GDB | |
674 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
675 | * Index:: Index | |
676 | @end menu | |
677 | @end ifset | |
678 | @end ifclear | |
679 | @end ifset | |
680 | @end ifclear | |
681 | ||
682 | @c Menu for !NOVEL && BARETARGET && CONLY && !DOSHOST | |
683 | @ifclear NOVEL | |
684 | @ifset BARETARGET | |
685 | @ifset CONLY | |
686 | @ifclear DOSHOST | |
687 | @menu | |
688 | * Summary:: Summary of @value{GDBN} | |
689 | * Invocation:: Getting in and out of @value{GDBN} | |
690 | * Commands:: @value{GDBN} commands | |
691 | * Running:: Running programs under @value{GDBN} | |
692 | * Stopping:: Stopping and continuing | |
693 | * Stack:: Examining the stack | |
694 | * Source:: Examining source files | |
695 | * Data:: Examining data | |
696 | * C:: C Language Support | |
697 | * Symbols:: Examining the symbol table | |
698 | * Altering:: Altering execution | |
699 | * GDB Files:: @value{GDBN}'s files | |
700 | * Targets:: Specifying a debugging target | |
701 | * Controlling GDB:: Controlling @value{GDBN} | |
702 | * Sequences:: Canned sequences of commands | |
703 | * Emacs:: Using @value{GDBN} under GNU Emacs | |
704 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
705 | * Formatting Documentation:: How to format and print GDB documentation | |
706 | * Installing GDB:: Installing GDB | |
707 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
708 | * Index:: Index | |
709 | @end menu | |
710 | @end ifclear | |
711 | @end ifset | |
712 | @end ifset | |
713 | @end ifclear | |
714 | ||
715 | @c Menu for !NOVEL && BARETARGET && CONLY && DOSHOST | |
716 | @ifclear NOVEL | |
717 | @ifset BARETARGET | |
718 | @ifset CONLY | |
719 | @ifset DOSHOST | |
720 | @menu | |
721 | * Summary:: Summary of @value{GDBN} | |
722 | * Invocation:: Getting in and out of @value{GDBN} | |
723 | * Commands:: @value{GDBN} commands | |
724 | * Running:: Running programs under @value{GDBN} | |
725 | * Stopping:: Stopping and continuing | |
726 | * Stack:: Examining the stack | |
727 | * Source:: Examining source files | |
728 | * Data:: Examining data | |
729 | * C:: C Language Support | |
730 | * Symbols:: Examining the symbol table | |
731 | * Altering:: Altering execution | |
732 | * GDB Files:: @value{GDBN}'s files | |
733 | * Targets:: Specifying a debugging target | |
734 | * Controlling GDB:: Controlling @value{GDBN} | |
735 | * Sequences:: Canned sequences of commands | |
736 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
737 | * Formatting Documentation:: How to format and print GDB documentation | |
738 | * Installing GDB:: Installing GDB | |
739 | * Copying:: GNU GENERAL PUBLIC LICENSE | |
740 | * Index:: Index | |
741 | @end menu | |
742 | @end ifset | |
743 | @end ifset | |
744 | @end ifset | |
745 | @end ifclear | |
746 | ||
747 | @end ifinfo | |
70b88761 | 748 | |
4eb4cf57 | 749 | @node Summary |
18fae2a8 | 750 | @unnumbered Summary of @value{GDBN} |
70b88761 | 751 | |
18fae2a8 | 752 | The purpose of a debugger such as @value{GDBN} is to allow you to see what is |
70b88761 | 753 | going on ``inside'' another program while it executes---or what another |
1041a570 | 754 | program was doing at the moment it crashed. |
70b88761 | 755 | |
18fae2a8 | 756 | @value{GDBN} can do four main kinds of things (plus other things in support of |
1041a570 | 757 | these) to help you catch bugs in the act: |
70b88761 RP |
758 | |
759 | @itemize @bullet | |
760 | @item | |
761 | Start your program, specifying anything that might affect its behavior. | |
762 | ||
763 | @item | |
764 | Make your program stop on specified conditions. | |
765 | ||
766 | @item | |
767 | Examine what has happened, when your program has stopped. | |
768 | ||
769 | @item | |
770 | Change things in your program, so you can experiment with correcting the | |
771 | effects of one bug and go on to learn about another. | |
772 | @end itemize | |
773 | ||
18fae2a8 RP |
774 | @ifclear CONLY |
775 | You can use @value{GDBN} to debug programs written in C, C++, and Modula-2. | |
c2bbbb22 | 776 | Fortran support will be added when a GNU Fortran compiler is ready. |
18fae2a8 | 777 | @end ifclear |
70b88761 RP |
778 | |
779 | @menu | |
ed447b95 | 780 | * Free Software:: Freely redistributable software |
b80282d5 | 781 | * Contributors:: Contributors to GDB |
70b88761 RP |
782 | @end menu |
783 | ||
4eb4cf57 | 784 | @node Free Software |
70b88761 | 785 | @unnumberedsec Free Software |
1041a570 | 786 | |
18fae2a8 | 787 | @value{GDBN} is @dfn{free software}, protected by the GNU General Public License |
1041a570 | 788 | (GPL). The GPL gives you the freedom to copy or adapt a licensed |
70b88761 RP |
789 | program---but every person getting a copy also gets with it the |
790 | freedom to modify that copy (which means that they must get access to | |
791 | the source code), and the freedom to distribute further copies. | |
792 | Typical software companies use copyrights to limit your freedoms; the | |
793 | Free Software Foundation uses the GPL to preserve these freedoms. | |
794 | ||
795 | Fundamentally, the General Public License is a license which says that | |
29a2b744 | 796 | you have these freedoms and that you cannot take these freedoms away |
70b88761 RP |
797 | from anyone else. |
798 | ||
18fae2a8 | 799 | @ifclear AGGLOMERATION |
29a2b744 | 800 | For full details, @pxref{Copying, ,GNU GENERAL PUBLIC LICENSE}. |
18fae2a8 | 801 | @end ifclear |
1041a570 | 802 | |
4eb4cf57 | 803 | @node Contributors |
70b88761 RP |
804 | @unnumberedsec Contributors to GDB |
805 | ||
806 | Richard Stallman was the original author of GDB, and of many other GNU | |
807 | programs. Many others have contributed to its development. This | |
808 | section attempts to credit major contributors. One of the virtues of | |
809 | free software is that everyone is free to contribute to it; with | |
810 | regret, we cannot actually acknowledge everyone here. The file | |
811 | @file{ChangeLog} in the GDB distribution approximates a blow-by-blow | |
812 | account. | |
813 | ||
814 | Changes much prior to version 2.0 are lost in the mists of time. | |
815 | ||
816 | @quotation | |
817 | @emph{Plea:} Additions to this section are particularly welcome. If you | |
818 | or your friends (or enemies; let's be evenhanded) have been unfairly | |
819 | omitted from this list, we would like to add your names! | |
820 | @end quotation | |
821 | ||
822 | So that they may not regard their long labor as thankless, we | |
69bbcf05 | 823 | particularly thank those who shepherded GDB through major releases: Stu |
6f3ec223 RP |
824 | Grossman and John Gilmore (releases 4.6, 4.5, 4.4), John Gilmore |
825 | (releases 4.3, 4.2, 4.1, 4.0, and 3.9); Jim Kingdon (releases 3.5, 3.4, | |
826 | 3.3); and Randy Smith (releases 3.2, 3.1, 3.0). As major maintainer of | |
827 | GDB for some period, each contributed significantly to the structure, | |
828 | stability, and capabilities of the entire debugger. | |
70b88761 RP |
829 | |
830 | Richard Stallman, assisted at various times by Pete TerMaat, Chris | |
831 | Hanson, and Richard Mlynarik, handled releases through 2.8. | |
832 | ||
833 | Michael Tiemann is the author of most of the GNU C++ support in GDB, | |
834 | with significant additional contributions from Per Bothner. James | |
835 | Clark wrote the GNU C++ demangler. Early work on C++ was by Peter | |
836 | TerMaat (who also did much general update work leading to release 3.0). | |
837 | ||
1041a570 RP |
838 | GDB 4 uses the BFD subroutine library to examine multiple |
839 | object-file formats; BFD was a joint project of David V. | |
840 | Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore. | |
70b88761 | 841 | |
1041a570 RP |
842 | David Johnson wrote the original COFF support; Pace Willison did |
843 | the original support for encapsulated COFF. | |
70b88761 RP |
844 | |
845 | Adam de Boor and Bradley Davis contributed the ISI Optimum V support. | |
846 | Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS | |
1041a570 RP |
847 | support. Jean-Daniel Fekete contributed Sun 386i support. Chris |
848 | Hanson improved the HP9000 support. Noboyuki Hikichi and Tomoyuki | |
849 | Hasei contributed Sony/News OS 3 support. David Johnson contributed | |
850 | Encore Umax support. Jyrki Kuoppala contributed Altos 3068 support. | |
851 | Keith Packard contributed NS32K support. Doug Rabson contributed | |
852 | Acorn Risc Machine support. Chris Smith contributed Convex support | |
853 | (and Fortran debugging). Jonathan Stone contributed Pyramid support. | |
854 | Michael Tiemann contributed SPARC support. Tim Tucker contributed | |
855 | support for the Gould NP1 and Gould Powernode. Pace Willison | |
856 | contributed Intel 386 support. Jay Vosburgh contributed Symmetry | |
857 | support. | |
70b88761 | 858 | |
c338a2fd RP |
859 | Rich Schaefer and Peter Schauer helped with support of SunOS shared |
860 | libraries. | |
70b88761 RP |
861 | |
862 | Jay Fenlason and Roland McGrath ensured that GDB and GAS agree about | |
863 | several machine instruction sets. | |
864 | ||
1041a570 RP |
865 | Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped |
866 | develop remote debugging. Intel Corporation and Wind River Systems | |
867 | contributed remote debugging modules for their products. | |
70b88761 | 868 | |
1041a570 RP |
869 | Brian Fox is the author of the readline libraries providing |
870 | command-line editing and command history. | |
70b88761 | 871 | |
1041a570 RP |
872 | Andrew Beers of SUNY Buffalo wrote the language-switching code and |
873 | the Modula-2 support, and contributed the Languages chapter of this | |
874 | manual. | |
c2bbbb22 | 875 | |
6f3ec223 RP |
876 | Fred Fish wrote most of the support for Unix System Vr4, and enhanced |
877 | the command-completion support to cover C++ overloaded symbols. | |
14d01801 | 878 | |
18fae2a8 | 879 | @ifset NOVEL |
4eb4cf57 | 880 | @node New Features |
ed447b95 | 881 | @unnumbered New Features since GDB Version 3.5 |
70b88761 RP |
882 | |
883 | @table @emph | |
884 | @item Targets | |
885 | Using the new command @code{target}, you can select at runtime whether | |
886 | you are debugging local files, local processes, standalone systems over | |
b80282d5 RP |
887 | a serial port, realtime systems over a TCP/IP connection, etc. The |
888 | command @code{load} can download programs into a remote system. Serial | |
b21b18e1 RP |
889 | stubs are available for Motorola 680x0, Intel 80386, and Sparc remote |
890 | systems; GDB also supports debugging realtime processes running under | |
b80282d5 | 891 | VxWorks, using SunRPC Remote Procedure Calls over TCP/IP to talk to a |
b21b18e1 RP |
892 | debugger stub on the target system. Internally, GDB now uses a function |
893 | vector to mediate access to different targets; if you need to add your | |
894 | own support for a remote protocol, this makes it much easier. | |
70b88761 RP |
895 | |
896 | @item Watchpoints | |
c7cb8acb | 897 | GDB now sports watchpoints as well as breakpoints. You can use a |
70b88761 RP |
898 | watchpoint to stop execution whenever the value of an expression |
899 | changes, without having to predict a particular place in your program | |
900 | where this may happen. | |
901 | ||
b80282d5 RP |
902 | @item Wide Output |
903 | Commands that issue wide output now insert newlines at places designed | |
904 | to make the output more readable. | |
905 | ||
70b88761 | 906 | @item Object Code Formats |
c7cb8acb | 907 | GDB uses a new library called the Binary File Descriptor (BFD) |
3d3ab540 RP |
908 | Library to permit it to switch dynamically, without reconfiguration or |
909 | recompilation, between different object-file formats. Formats currently | |
910 | supported are COFF, a.out, and the Intel 960 b.out; files may be read as | |
911 | .o's, archive libraries, or core dumps. BFD is available as a | |
912 | subroutine library so that other programs may take advantage of it, and | |
913 | the other GNU binary utilities are being converted to use it. | |
70b88761 | 914 | |
b80282d5 | 915 | @item Configuration and Ports |
70b88761 | 916 | Compile-time configuration (to select a particular architecture and |
7463aadd | 917 | operating system) is much easier. The script @code{configure} now |
c7cb8acb RP |
918 | allows you to configure GDB as either a native debugger or a |
919 | cross-debugger. @xref{Installing GDB}, for details on how to | |
6a8cb0e7 | 920 | configure. |
70b88761 RP |
921 | |
922 | @item Interaction | |
c7cb8acb | 923 | The user interface to GDB's control variables has been simplified |
70b88761 RP |
924 | and consolidated in two commands, @code{set} and @code{show}. Output |
925 | lines are now broken at readable places, rather than overflowing onto | |
926 | the next line. You can suppress output of machine-level addresses, | |
927 | displaying only source language information. | |
928 | ||
b80282d5 | 929 | @item C++ |
c7cb8acb | 930 | GDB now supports C++ multiple inheritance (if used with a GCC |
b80282d5 | 931 | version 2 compiler), and also has limited support for C++ exception |
c7cb8acb | 932 | handling, with the commands @code{catch} and @code{info catch}: GDB |
b80282d5 RP |
933 | can break when an exception is raised, before the stack is peeled back |
934 | to the exception handler's context. | |
70b88761 | 935 | |
c2bbbb22 | 936 | @item Modula-2 |
ed447b95 RP |
937 | GDB now has preliminary support for the GNU Modula-2 compiler, currently |
938 | under development at the State University of New York at Buffalo. | |
939 | Coordinated development of both GDB and the GNU Modula-2 compiler will | |
940 | continue. Other Modula-2 compilers are currently not supported, and | |
941 | attempting to debug programs compiled with them will likely result in an | |
942 | error as the symbol table of the executable is read in. | |
c2bbbb22 | 943 | |
70b88761 | 944 | @item Command Rationalization |
c7cb8acb | 945 | Many GDB commands have been renamed to make them easier to remember |
70b88761 RP |
946 | and use. In particular, the subcommands of @code{info} and |
947 | @code{show}/@code{set} are grouped to make the former refer to the state | |
c7cb8acb | 948 | of your program, and the latter refer to the state of GDB itself. |
70b88761 RP |
949 | @xref{Renamed Commands}, for details on what commands were renamed. |
950 | ||
70b88761 | 951 | @item Shared Libraries |
77b46d13 JG |
952 | GDB 4 can debug programs and core files that use SunOS, SVR4, or IBM RS/6000 |
953 | shared libraries. | |
b80282d5 RP |
954 | |
955 | @item Reference Card | |
6f3ec223 | 956 | GDB 4 has a reference card. @xref{Formatting Documentation,,Formatting |
ed447b95 | 957 | the Documentation}, for instructions about how to print it. |
70b88761 RP |
958 | |
959 | @item Work in Progress | |
960 | Kernel debugging for BSD and Mach systems; Tahoe and HPPA architecture | |
961 | support. | |
70b88761 | 962 | @end table |
18fae2a8 | 963 | @end ifset |
70b88761 | 964 | |
18fae2a8 | 965 | @ifclear BARETARGET |
4eb4cf57 | 966 | @node Sample Session |
18fae2a8 | 967 | @chapter A Sample @value{GDBN} Session |
70b88761 | 968 | |
18fae2a8 | 969 | You can use this manual at your leisure to read all about @value{GDBN}. |
70b88761 | 970 | However, a handful of commands are enough to get started using the |
ed447b95 | 971 | debugger. This chapter illustrates those commands. |
70b88761 RP |
972 | |
973 | @iftex | |
6ca72cc6 | 974 | In this sample session, we emphasize user input like this: @b{input}, |
70b88761 RP |
975 | to make it easier to pick out from the surrounding output. |
976 | @end iftex | |
977 | ||
978 | @c FIXME: this example may not be appropriate for some configs, where | |
979 | @c FIXME...primary interest is in remote use. | |
18fae2a8 | 980 | |
70b88761 RP |
981 | One of the preliminary versions of GNU @code{m4} (a generic macro |
982 | processor) exhibits the following bug: sometimes, when we change its | |
983 | quote strings from the default, the commands used to capture one macro's | |
984 | definition in another stop working. In the following short @code{m4} | |
985 | session, we define a macro @code{foo} which expands to @code{0000}; we | |
29a2b744 | 986 | then use the @code{m4} built-in @code{defn} to define @code{bar} as the |
70b88761 RP |
987 | same thing. However, when we change the open quote string to |
988 | @code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same | |
989 | procedure fails to define a new synonym @code{baz}: | |
990 | ||
991 | @smallexample | |
6ca72cc6 RP |
992 | $ @b{cd gnu/m4} |
993 | $ @b{./m4} | |
994 | @b{define(foo,0000)} | |
70b88761 | 995 | |
6ca72cc6 | 996 | @b{foo} |
70b88761 | 997 | 0000 |
6ca72cc6 | 998 | @b{define(bar,defn(`foo'))} |
70b88761 | 999 | |
6ca72cc6 | 1000 | @b{bar} |
70b88761 | 1001 | 0000 |
6ca72cc6 | 1002 | @b{changequote(<QUOTE>,<UNQUOTE>)} |
70b88761 | 1003 | |
6ca72cc6 RP |
1004 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} |
1005 | @b{baz} | |
1006 | @b{C-d} | |
70b88761 RP |
1007 | m4: End of input: 0: fatal error: EOF in string |
1008 | @end smallexample | |
1009 | ||
1010 | @noindent | |
18fae2a8 | 1011 | Let's use @value{GDBN} to try to see what's going on. |
70b88761 RP |
1012 | |
1013 | @smallexample | |
18fae2a8 | 1014 | $ @b{@value{GDBP} m4} |
203eea5d RP |
1015 | @c FIXME: this falsifies the exact text played out, to permit smallbook |
1016 | @c FIXME... format to come out better. | |
1017 | GDB is free software and you are welcome to distribute copies | |
1018 | of it under certain conditions; type "show copying" to see | |
1019 | the conditions. | |
1020 | There is absolutely no warranty for GDB; type "show warranty" | |
ed447b95 RP |
1021 | for details. |
1022 | GDB @value{GDBVN}, Copyright 1993 Free Software Foundation, Inc... | |
18fae2a8 | 1023 | (@value{GDBP}) |
70b88761 RP |
1024 | @end smallexample |
1025 | ||
1026 | @noindent | |
18fae2a8 | 1027 | @value{GDBN} reads only enough symbol data to know where to find the rest when |
1041a570 | 1028 | needed; as a result, the first prompt comes up very quickly. We now |
18fae2a8 | 1029 | tell @value{GDBN} to use a narrower display width than usual, so that examples |
1041a570 | 1030 | will fit in this manual. |
70b88761 RP |
1031 | |
1032 | @smallexample | |
18fae2a8 | 1033 | (@value{GDBP}) @b{set width 70} |
70b88761 RP |
1034 | @end smallexample |
1035 | ||
e251e767 | 1036 | @noindent |
29a2b744 | 1037 | Let's see how the @code{m4} built-in @code{changequote} works. |
70b88761 | 1038 | Having looked at the source, we know the relevant subroutine is |
18fae2a8 | 1039 | @code{m4_changequote}, so we set a breakpoint there with @value{GDBN}'s |
70b88761 RP |
1040 | @code{break} command. |
1041 | ||
1042 | @smallexample | |
18fae2a8 | 1043 | (@value{GDBP}) @b{break m4_changequote} |
70b88761 RP |
1044 | Breakpoint 1 at 0x62f4: file builtin.c, line 879. |
1045 | @end smallexample | |
1046 | ||
1047 | @noindent | |
18fae2a8 | 1048 | Using the @code{run} command, we start @code{m4} running under @value{GDBN} |
70b88761 RP |
1049 | control; as long as control does not reach the @code{m4_changequote} |
1050 | subroutine, the program runs as usual: | |
1051 | ||
1052 | @smallexample | |
18fae2a8 | 1053 | (@value{GDBP}) @b{run} |
e251e767 | 1054 | Starting program: /work/Editorial/gdb/gnu/m4/m4 |
6ca72cc6 | 1055 | @b{define(foo,0000)} |
70b88761 | 1056 | |
6ca72cc6 | 1057 | @b{foo} |
70b88761 RP |
1058 | 0000 |
1059 | @end smallexample | |
1060 | ||
1061 | @noindent | |
18fae2a8 | 1062 | To trigger the breakpoint, we call @code{changequote}. @value{GDBN} |
70b88761 RP |
1063 | suspends execution of @code{m4}, displaying information about the |
1064 | context where it stops. | |
1065 | ||
1066 | @smallexample | |
6ca72cc6 | 1067 | @b{changequote(<QUOTE>,<UNQUOTE>)} |
70b88761 | 1068 | |
203eea5d RP |
1069 | Breakpoint 1, m4_changequote (argc=3, argv=0x33c70) |
1070 | at builtin.c:879 | |
38962738 | 1071 | 879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]),argc,1,3)) |
70b88761 RP |
1072 | @end smallexample |
1073 | ||
1074 | @noindent | |
1075 | Now we use the command @code{n} (@code{next}) to advance execution to | |
1076 | the next line of the current function. | |
1077 | ||
1078 | @smallexample | |
18fae2a8 | 1079 | (@value{GDBP}) @b{n} |
203eea5d RP |
1080 | 882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\ |
1081 | : nil, | |
70b88761 RP |
1082 | @end smallexample |
1083 | ||
1084 | @noindent | |
1085 | @code{set_quotes} looks like a promising subroutine. We can go into it | |
1086 | by using the command @code{s} (@code{step}) instead of @code{next}. | |
1087 | @code{step} goes to the next line to be executed in @emph{any} | |
e251e767 | 1088 | subroutine, so it steps into @code{set_quotes}. |
70b88761 RP |
1089 | |
1090 | @smallexample | |
18fae2a8 | 1091 | (@value{GDBP}) @b{s} |
70b88761 RP |
1092 | set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") |
1093 | at input.c:530 | |
1094 | 530 if (lquote != def_lquote) | |
1095 | @end smallexample | |
1096 | ||
1097 | @noindent | |
29a2b744 RP |
1098 | The display that shows the subroutine where @code{m4} is now |
1099 | suspended (and its arguments) is called a stack frame display. It | |
1100 | shows a summary of the stack. We can use the @code{backtrace} | |
1101 | command (which can also be spelled @code{bt}), to see where we are | |
1102 | in the stack as a whole: the @code{backtrace} command displays a | |
1103 | stack frame for each active subroutine. | |
70b88761 RP |
1104 | |
1105 | @smallexample | |
18fae2a8 | 1106 | (@value{GDBP}) @b{bt} |
70b88761 RP |
1107 | #0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") |
1108 | at input.c:530 | |
203eea5d RP |
1109 | #1 0x6344 in m4_changequote (argc=3, argv=0x33c70) |
1110 | at builtin.c:882 | |
70b88761 RP |
1111 | #2 0x8174 in expand_macro (sym=0x33320) at macro.c:242 |
1112 | #3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30) | |
1113 | at macro.c:71 | |
1114 | #4 0x79dc in expand_input () at macro.c:40 | |
1115 | #5 0x2930 in main (argc=0, argv=0xf7fffb20) at m4.c:195 | |
1116 | @end smallexample | |
1117 | ||
1118 | @noindent | |
1119 | Let's step through a few more lines to see what happens. The first two | |
1120 | times, we can use @samp{s}; the next two times we use @code{n} to avoid | |
1121 | falling into the @code{xstrdup} subroutine. | |
1041a570 | 1122 | |
70b88761 | 1123 | @smallexample |
18fae2a8 | 1124 | (@value{GDBP}) @b{s} |
70b88761 | 1125 | 0x3b5c 532 if (rquote != def_rquote) |
18fae2a8 | 1126 | (@value{GDBP}) @b{s} |
203eea5d RP |
1127 | 0x3b80 535 lquote = (lq == nil || *lq == '\0') ? \ |
1128 | def_lquote : xstrdup(lq); | |
18fae2a8 | 1129 | (@value{GDBP}) @b{n} |
203eea5d RP |
1130 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ |
1131 | : xstrdup(rq); | |
18fae2a8 | 1132 | (@value{GDBP}) @b{n} |
70b88761 RP |
1133 | 538 len_lquote = strlen(rquote); |
1134 | @end smallexample | |
1135 | ||
1136 | @noindent | |
1137 | The last line displayed looks a little odd; let's examine the variables | |
1138 | @code{lquote} and @code{rquote} to see if they are in fact the new left | |
1139 | and right quotes we specified. We can use the command @code{p} | |
1140 | (@code{print}) to see their values. | |
1141 | ||
1142 | @smallexample | |
18fae2a8 | 1143 | (@value{GDBP}) @b{p lquote} |
70b88761 | 1144 | $1 = 0x35d40 "<QUOTE>" |
18fae2a8 | 1145 | (@value{GDBP}) @b{p rquote} |
70b88761 RP |
1146 | $2 = 0x35d50 "<UNQUOTE>" |
1147 | @end smallexample | |
1148 | ||
1149 | @noindent | |
1150 | @code{lquote} and @code{rquote} are indeed the new left and right quotes. | |
1151 | Let's look at some context; we can display ten lines of source | |
1152 | surrounding the current line, with the @code{l} (@code{list}) command. | |
1153 | ||
1154 | @smallexample | |
18fae2a8 | 1155 | (@value{GDBP}) @b{l} |
70b88761 | 1156 | 533 xfree(rquote); |
e251e767 | 1157 | 534 |
203eea5d RP |
1158 | 535 lquote = (lq == nil || *lq == '\0') ? def_lquote\ |
1159 | : xstrdup (lq); | |
1160 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
1161 | : xstrdup (rq); | |
e251e767 | 1162 | 537 |
70b88761 RP |
1163 | 538 len_lquote = strlen(rquote); |
1164 | 539 len_rquote = strlen(lquote); | |
1165 | 540 @} | |
e251e767 | 1166 | 541 |
70b88761 RP |
1167 | 542 void |
1168 | @end smallexample | |
1169 | ||
1170 | @noindent | |
1171 | Let's step past the two lines that set @code{len_lquote} and | |
1172 | @code{len_rquote}, and then examine the values of those variables. | |
1173 | ||
1174 | @smallexample | |
18fae2a8 | 1175 | (@value{GDBP}) @b{n} |
70b88761 | 1176 | 539 len_rquote = strlen(lquote); |
18fae2a8 | 1177 | (@value{GDBP}) @b{n} |
70b88761 | 1178 | 540 @} |
18fae2a8 | 1179 | (@value{GDBP}) @b{p len_lquote} |
70b88761 | 1180 | $3 = 9 |
18fae2a8 | 1181 | (@value{GDBP}) @b{p len_rquote} |
70b88761 RP |
1182 | $4 = 7 |
1183 | @end smallexample | |
1184 | ||
1185 | @noindent | |
1186 | That certainly looks wrong, assuming @code{len_lquote} and | |
1187 | @code{len_rquote} are meant to be the lengths of @code{lquote} and | |
1188 | @code{rquote} respectively. Let's try setting them to better values. | |
1189 | We can use the @code{p} command for this, since it'll print the value of | |
1190 | any expression---and that expression can include subroutine calls and | |
e251e767 | 1191 | assignments. |
70b88761 RP |
1192 | |
1193 | @smallexample | |
18fae2a8 | 1194 | (@value{GDBP}) @b{p len_lquote=strlen(lquote)} |
70b88761 | 1195 | $5 = 7 |
18fae2a8 | 1196 | (@value{GDBP}) @b{p len_rquote=strlen(rquote)} |
70b88761 RP |
1197 | $6 = 9 |
1198 | @end smallexample | |
1199 | ||
1200 | @noindent | |
1201 | Let's see if that fixes the problem of using the new quotes with the | |
1202 | @code{m4} built-in @code{defn}. We can allow @code{m4} to continue | |
1203 | executing with the @code{c} (@code{continue}) command, and then try the | |
1204 | example that caused trouble initially: | |
1205 | ||
1206 | @smallexample | |
18fae2a8 | 1207 | (@value{GDBP}) @b{c} |
70b88761 RP |
1208 | Continuing. |
1209 | ||
6ca72cc6 | 1210 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} |
70b88761 RP |
1211 | |
1212 | baz | |
1213 | 0000 | |
1214 | @end smallexample | |
1215 | ||
1216 | @noindent | |
1217 | Success! The new quotes now work just as well as the default ones. The | |
1218 | problem seems to have been just the two typos defining the wrong | |
1219 | lengths. We'll let @code{m4} exit by giving it an EOF as input. | |
1220 | ||
1221 | @smallexample | |
6ca72cc6 | 1222 | @b{C-d} |
70b88761 RP |
1223 | Program exited normally. |
1224 | @end smallexample | |
1225 | ||
e251e767 | 1226 | @noindent |
18fae2a8 RP |
1227 | The message @samp{Program exited normally.} is from @value{GDBN}; it |
1228 | indicates @code{m4} has finished executing. We can end our @value{GDBN} | |
1229 | session with the @value{GDBN} @code{quit} command. | |
70b88761 RP |
1230 | |
1231 | @smallexample | |
18fae2a8 RP |
1232 | (@value{GDBP}) @b{quit} |
1233 | @end smallexample | |
1234 | @end ifclear | |
70b88761 | 1235 | |
4eb4cf57 | 1236 | @node Invocation |
18fae2a8 | 1237 | @chapter Getting In and Out of @value{GDBN} |
70b88761 | 1238 | |
18fae2a8 RP |
1239 | This chapter discusses how to start @value{GDBN}, and how to get out of it. |
1240 | (The essentials: type @samp{@value{GDBP}} to start GDB, and type @kbd{quit} | |
c7cb8acb | 1241 | or @kbd{C-d} to exit.) |
29a2b744 | 1242 | |
18fae2a8 RP |
1243 | @ignore |
1244 | @c original form of menu, pre-unfolding: | |
70b88761 | 1245 | @menu |
ed447b95 RP |
1246 | * Invoking GDB:: How to start @value{GDBN} |
1247 | * Quitting GDB:: How to quit @value{GDBN} | |
18fae2a8 | 1248 | @ifclear BARETARGET |
ed447b95 | 1249 | * Shell Commands:: How to use shell commands inside @value{GDBN} |
18fae2a8 | 1250 | @end ifclear |
70b88761 | 1251 | @end menu |
18fae2a8 | 1252 | @end ignore |
70b88761 | 1253 | |
18fae2a8 RP |
1254 | @ifclear BARETARGET |
1255 | @menu | |
ed447b95 RP |
1256 | * Invoking GDB:: How to start @value{GDBN} |
1257 | * Quitting GDB:: How to quit @value{GDBN} | |
1258 | * Shell Commands:: How to use shell commands inside @value{GDBN} | |
18fae2a8 RP |
1259 | @end menu |
1260 | @end ifclear | |
70b88761 | 1261 | |
18fae2a8 RP |
1262 | @ifset BARETARGET |
1263 | @menu | |
ed447b95 RP |
1264 | * Invoking GDB:: How to start @value{GDBN} |
1265 | * Quitting GDB:: How to quit @value{GDBN} | |
18fae2a8 RP |
1266 | @end menu |
1267 | @end ifset | |
1268 | ||
1269 | @node Invoking GDB | |
ed447b95 | 1270 | @section Invoking @value{GDBN} |
18fae2a8 RP |
1271 | |
1272 | @ifset HviiiEXCLUSIVE | |
1273 | For details on starting up @value{GDBP} as a | |
4eb4cf57 | 1274 | remote debugger attached to a Hitachi H8/300 board, see @ref{Hitachi |
18fae2a8 RP |
1275 | H8/300 Remote,,@value{GDBN} and the Hitachi H8/300}. |
1276 | @end ifset | |
4eb4cf57 | 1277 | |
ed447b95 | 1278 | Invoke @value{GDBN} by running the program @code{@value{GDBP}}. Once started, |
18fae2a8 | 1279 | @value{GDBN} reads commands from the terminal until you tell it to exit. |
70b88761 | 1280 | |
18fae2a8 | 1281 | You can also run @code{@value{GDBP}} with a variety of arguments and options, |
c7cb8acb RP |
1282 | to specify more of your debugging environment at the outset. |
1283 | ||
18fae2a8 | 1284 | @ifset GENERIC |
c7cb8acb RP |
1285 | The command-line options described here are designed |
1286 | to cover a variety of situations; in some environments, some of these | |
1287 | options may effectively be unavailable. | |
18fae2a8 | 1288 | @end ifset |
c7cb8acb | 1289 | |
18fae2a8 | 1290 | The most usual way to start @value{GDBN} is with one argument, |
4eb4cf57 | 1291 | specifying an executable program: |
1041a570 | 1292 | |
70b88761 | 1293 | @example |
18fae2a8 | 1294 | @value{GDBP} @var{program} |
70b88761 | 1295 | @end example |
1041a570 | 1296 | |
18fae2a8 | 1297 | @ifclear BARETARGET |
70b88761 | 1298 | @noindent |
29a2b744 RP |
1299 | You can also start with both an executable program and a core file |
1300 | specified: | |
1041a570 | 1301 | |
70b88761 | 1302 | @example |
18fae2a8 | 1303 | @value{GDBP} @var{program} @var{core} |
70b88761 RP |
1304 | @end example |
1305 | ||
b80282d5 RP |
1306 | You can, instead, specify a process ID as a second argument, if you want |
1307 | to debug a running process: | |
1041a570 | 1308 | |
b80282d5 | 1309 | @example |
18fae2a8 | 1310 | @value{GDBP} @var{program} 1234 |
b80282d5 | 1311 | @end example |
1041a570 | 1312 | |
b80282d5 | 1313 | @noindent |
18fae2a8 RP |
1314 | would attach @value{GDBN} to process @code{1234} (unless you also have a file |
1315 | named @file{1234}; @value{GDBN} does check for a core file first). | |
b80282d5 | 1316 | |
c7cb8acb | 1317 | Taking advantage of the second command-line argument requires a fairly |
18fae2a8 | 1318 | complete operating system; when you use @value{GDBN} as a remote debugger |
c7cb8acb RP |
1319 | attached to a bare board, there may not be any notion of ``process'', |
1320 | and there is often no way to get a core dump. | |
18fae2a8 | 1321 | @end ifclear |
c7cb8acb | 1322 | |
70b88761 | 1323 | @noindent |
18fae2a8 RP |
1324 | You can further control how @value{GDBN} starts up by using command-line |
1325 | options. @value{GDBN} itself can remind you of the options available. | |
29a2b744 RP |
1326 | |
1327 | @noindent | |
1328 | Type | |
1329 | ||
70b88761 | 1330 | @example |
18fae2a8 | 1331 | @value{GDBP} -help |
70b88761 | 1332 | @end example |
29a2b744 | 1333 | |
70b88761 | 1334 | @noindent |
29a2b744 | 1335 | to display all available options and briefly describe their use |
18fae2a8 | 1336 | (@samp{@value{GDBP} -h} is a shorter equivalent). |
70b88761 RP |
1337 | |
1338 | All options and command line arguments you give are processed | |
1339 | in sequential order. The order makes a difference when the | |
e251e767 | 1340 | @samp{-x} option is used. |
70b88761 | 1341 | |
18fae2a8 RP |
1342 | |
1343 | @ignore | |
1344 | @c original, intended form of this menu (pre-unfolding): | |
70b88761 | 1345 | @menu |
18fae2a8 RP |
1346 | @ifclear GENERIC |
1347 | @ifset REMOTESTUB | |
1348 | * Remote Serial:: @value{GDBN} remote serial protocol | |
1349 | @end ifset | |
1350 | @ifset Icmlx | |
1351 | * i960-Nindy Remote:: @value{GDBN} with a remote i960 (Nindy) | |
1352 | @end ifset | |
1353 | @ifset AMDxxixK | |
1354 | * EB29K Remote:: @value{GDBN} with a remote EB29K | |
1355 | @end ifset | |
1356 | @ifset VXWORKS | |
1357 | * VxWorks Remote:: @value{GDBN} and VxWorks | |
1358 | @end ifset | |
1359 | @ifset STmm | |
1360 | * ST2000 Remote:: @value{GDBN} with a Tandem ST2000 | |
1361 | @end ifset | |
1362 | @ifset Hviii | |
1363 | * Hitachi H8/300 Remote:: @value{GDBN} and the Hitachi H8/300 | |
1364 | @end ifset | |
1365 | @ifset ZviiiK | |
1366 | * Z8000 Simulator:: @value{GDBN} and its Zilog Z8000 Simulator | |
1367 | @end ifset | |
1368 | @end ifclear | |
ed447b95 RP |
1369 | * File Options:: Choosing files |
1370 | * Mode Options:: Choosing modes | |
70b88761 | 1371 | @end menu |
18fae2a8 | 1372 | @end ignore |
70b88761 | 1373 | |
18fae2a8 RP |
1374 | @c Unfolded form: |
1375 | @c Sigh--- GENERIC plus 7 switches mean 1+2^7 forms of this menu! | |
1376 | @c Add them only on demand; no point in including forms for which | |
1377 | @c there's no defined config file. Maybe by the time all are needed, | |
1378 | @c makeinfo will be capable of dealing with menus like the above. | |
1379 | ||
1380 | @ifset GENERIC | |
1381 | @menu | |
ed447b95 RP |
1382 | * File Options:: Choosing files |
1383 | * Mode Options:: Choosing modes | |
18fae2a8 RP |
1384 | @end menu |
1385 | @end ifset | |
1386 | ||
1387 | @c Hviii config: !GENERIC && Hviii && nothing else | |
1388 | @ifclear GENERIC | |
1389 | @ifclear REMOTESTUB | |
1390 | @ifclear Icmlx | |
1391 | @ifclear AMDxxixK | |
1392 | @ifclear VXWORKS | |
1393 | @ifclear STmm | |
1394 | @ifset Hviii | |
1395 | @ifclear ZviiiK | |
1396 | @menu | |
1397 | * Hitachi H8/300 Remote:: @value{GDBN} and the Hitachi H8/300 | |
ed447b95 RP |
1398 | * File Options:: Choosing files |
1399 | * Mode Options:: Choosing modes | |
18fae2a8 RP |
1400 | @end menu |
1401 | @end ifclear | |
1402 | @end ifset | |
1403 | @end ifclear | |
1404 | @end ifclear | |
1405 | @end ifclear | |
1406 | @end ifclear | |
1407 | @end ifclear | |
1408 | @end ifclear | |
1409 | ||
1410 | @ifclear GENERIC | |
1411 | @include gdbinv-s.texi | |
1412 | @end ifclear | |
4eb4cf57 RP |
1413 | |
1414 | @node File Options | |
70b88761 RP |
1415 | @subsection Choosing Files |
1416 | ||
18fae2a8 RP |
1417 | @ifclear BARETARGET |
1418 | When @value{GDBN} starts, it reads any arguments other than options as | |
29a2b744 RP |
1419 | specifying an executable file and core file (or process ID). This is |
1420 | the same as if the arguments were specified by the @samp{-se} and | |
18fae2a8 | 1421 | @samp{-c} options respectively. (@value{GDBN} reads the first argument |
29a2b744 RP |
1422 | that does not have an associated option flag as equivalent to the |
1423 | @samp{-se} option followed by that argument; and the second argument | |
1424 | that does not have an associated option flag, if any, as equivalent to | |
1425 | the @samp{-c} option followed by that argument.) | |
18fae2a8 RP |
1426 | @end ifclear |
1427 | @ifset BARETARGET | |
1428 | When @value{GDBN} starts, it reads any argument other than options as | |
4eb4cf57 RP |
1429 | specifying an executable file. This is the same as if the argument was |
1430 | specified by the @samp{-se} option. | |
18fae2a8 | 1431 | @end ifset |
29a2b744 RP |
1432 | |
1433 | Many options have both long and short forms; both are shown in the | |
18fae2a8 | 1434 | following list. @value{GDBN} also recognizes the long forms if you truncate |
29a2b744 RP |
1435 | them, so long as enough of the option is present to be unambiguous. |
1436 | (If you prefer, you can flag option arguments with @samp{--} rather | |
1437 | than @samp{-}, though we illustrate the more usual convention.) | |
70b88761 RP |
1438 | |
1439 | @table @code | |
1440 | @item -symbols=@var{file} | |
1441 | @itemx -s @var{file} | |
1442 | Read symbol table from file @var{file}. | |
1443 | ||
1444 | @item -exec=@var{file} | |
1445 | @itemx -e @var{file} | |
1446 | Use file @var{file} as the executable file to execute when | |
1447 | appropriate, and for examining pure data in conjunction with a core | |
1448 | dump. | |
1449 | ||
3d3ab540 | 1450 | @item -se=@var{file} |
70b88761 RP |
1451 | Read symbol table from file @var{file} and use it as the executable |
1452 | file. | |
1453 | ||
18fae2a8 | 1454 | @ifclear BARETARGET |
70b88761 RP |
1455 | @item -core=@var{file} |
1456 | @itemx -c @var{file} | |
1457 | Use file @var{file} as a core dump to examine. | |
18fae2a8 | 1458 | @end ifclear |
70b88761 RP |
1459 | |
1460 | @item -command=@var{file} | |
1461 | @itemx -x @var{file} | |
18fae2a8 | 1462 | Execute @value{GDBN} commands from file @var{file}. @xref{Command Files}. |
70b88761 RP |
1463 | |
1464 | @item -directory=@var{directory} | |
1465 | @itemx -d @var{directory} | |
1466 | Add @var{directory} to the path to search for source files. | |
14d01801 | 1467 | |
18fae2a8 | 1468 | @ifclear BARETARGET |
14d01801 RP |
1469 | @item -m |
1470 | @itemx -mapped | |
1471 | @emph{Warning: this option depends on operating system facilities that are not | |
1472 | supported on all systems.}@* | |
77b46d13 JG |
1473 | If memory-mapped files are available on your system through the @code{mmap} |
1474 | system call, you can use this option | |
18fae2a8 | 1475 | to have @value{GDBN} write the symbols from your |
77b46d13 JG |
1476 | program into a reusable file in the current directory. If the program you are debugging is |
1477 | called @file{/tmp/fred}, the mapped symbol file will be @file{./fred.syms}. | |
18fae2a8 | 1478 | Future @value{GDBN} debugging sessions will notice the presence of this file, |
77b46d13 JG |
1479 | and will quickly map in symbol information from it, rather than reading |
1480 | the symbol table from the executable program. | |
1481 | ||
18fae2a8 RP |
1482 | The @file{.syms} file is specific to the host machine on which @value{GDBN} is run. |
1483 | It holds an exact image of @value{GDBN}'s internal symbol table. It cannot be | |
77b46d13 | 1484 | shared across multiple host platforms. |
18fae2a8 | 1485 | @end ifclear |
77b46d13 JG |
1486 | |
1487 | @item -r | |
1488 | @itemx -readnow | |
1489 | Read each symbol file's entire symbol table immediately, rather than | |
1490 | the default, which is to read it incrementally as it is needed. | |
1491 | This makes startup slower, but makes future operations faster. | |
70b88761 RP |
1492 | @end table |
1493 | ||
18fae2a8 | 1494 | @ifclear BARETARGET |
77b46d13 JG |
1495 | The @code{-mapped} and @code{-readnow} options are typically combined in order to |
1496 | build a @file{.syms} file that contains complete symbol information. | |
1497 | A simple GDB invocation to do nothing but build a @file{.syms} file for future | |
1498 | use is: | |
1499 | ||
1500 | @example | |
1501 | gdb -batch -nx -mapped -readnow programname | |
1502 | @end example | |
18fae2a8 | 1503 | @end ifclear |
77b46d13 | 1504 | |
4eb4cf57 | 1505 | @node Mode Options |
1041a570 RP |
1506 | @subsection Choosing Modes |
1507 | ||
18fae2a8 | 1508 | You can run @value{GDBN} in various alternative modes---for example, in |
29a2b744 | 1509 | batch mode or quiet mode. |
70b88761 RP |
1510 | |
1511 | @table @code | |
1512 | @item -nx | |
1513 | @itemx -n | |
18fae2a8 | 1514 | Do not execute commands from any @file{@value{GDBINIT}} initialization files. |
70b88761 | 1515 | Normally, the commands in these files are executed after all the |
e251e767 | 1516 | command options and arguments have been processed. |
c728f1f0 | 1517 | @xref{Command Files}. |
70b88761 RP |
1518 | |
1519 | @item -quiet | |
1520 | @itemx -q | |
1521 | ``Quiet''. Do not print the introductory and copyright messages. These | |
c338a2fd | 1522 | messages are also suppressed in batch mode. |
70b88761 RP |
1523 | |
1524 | @item -batch | |
1525 | Run in batch mode. Exit with status @code{0} after processing all the command | |
18fae2a8 RP |
1526 | files specified with @samp{-x} (and @file{@value{GDBINIT}}, if not inhibited). |
1527 | Exit with nonzero status if an error occurs in executing the @value{GDBN} | |
e251e767 | 1528 | commands in the command files. |
70b88761 | 1529 | |
18fae2a8 | 1530 | Batch mode may be useful for running @value{GDBN} as a filter, for example to |
70b88761 | 1531 | download and run a program on another computer; in order to make this |
e251e767 | 1532 | more useful, the message |
1041a570 | 1533 | |
70b88761 RP |
1534 | @example |
1535 | Program exited normally. | |
1536 | @end example | |
1041a570 | 1537 | |
70b88761 | 1538 | @noindent |
18fae2a8 | 1539 | (which is ordinarily issued whenever a program running under @value{GDBN} control |
70b88761 RP |
1540 | terminates) is not issued when running in batch mode. |
1541 | ||
3d3ab540 | 1542 | @item -cd=@var{directory} |
18fae2a8 | 1543 | Run @value{GDBN} using @var{directory} as its working directory, |
70b88761 RP |
1544 | instead of the current directory. |
1545 | ||
18fae2a8 | 1546 | @ifset LUCID |
45c53080 | 1547 | @item -context @var{authentication} |
18fae2a8 | 1548 | When the Energize programming system starts up @value{GDBN}, it uses this |
6ca72cc6 | 1549 | option to trigger an alternate mode of interaction. |
18fae2a8 | 1550 | @var{authentication} is a pair of numeric codes that identify @value{GDBN} |
6ca72cc6 | 1551 | as a client in the Energize environment. Avoid this option when you run |
18fae2a8 RP |
1552 | @value{GDBN} directly from the command line. See @ref{Energize,,Using |
1553 | @value{GDBN} with Energize} for more discussion of using @value{GDBN} with Energize. | |
1554 | @end ifset | |
6ca72cc6 | 1555 | |
70b88761 RP |
1556 | @item -fullname |
1557 | @itemx -f | |
18fae2a8 | 1558 | Emacs sets this option when it runs @value{GDBN} as a subprocess. It tells @value{GDBN} |
70b88761 RP |
1559 | to output the full file name and line number in a standard, |
1560 | recognizable fashion each time a stack frame is displayed (which | |
29a2b744 | 1561 | includes each time your program stops). This recognizable format looks |
70b88761 RP |
1562 | like two @samp{\032} characters, followed by the file name, line number |
1563 | and character position separated by colons, and a newline. The | |
18fae2a8 | 1564 | Emacs-to-@value{GDBN} interface program uses the two @samp{\032} characters as |
70b88761 RP |
1565 | a signal to display the source code for the frame. |
1566 | ||
18fae2a8 | 1567 | @ifset SERIAL |
70b88761 RP |
1568 | @item -b @var{bps} |
1569 | Set the line speed (baud rate or bits per second) of any serial | |
18fae2a8 | 1570 | interface used by @value{GDBN} for remote debugging. |
70b88761 | 1571 | |
3d3ab540 | 1572 | @item -tty=@var{device} |
70b88761 | 1573 | Run using @var{device} for your program's standard input and output. |
29a2b744 | 1574 | @c FIXME: kingdon thinks there is more to -tty. Investigate. |
18fae2a8 | 1575 | @end ifset |
70b88761 RP |
1576 | @end table |
1577 | ||
ed447b95 RP |
1578 | @node Quitting GDB |
1579 | @section Quitting @value{GDBN} | |
18fae2a8 | 1580 | @cindex exiting @value{GDBN} |
ed447b95 | 1581 | @cindex leaving @value{GDBN} |
1041a570 | 1582 | |
70b88761 RP |
1583 | @table @code |
1584 | @item quit | |
1585 | @kindex quit | |
1586 | @kindex q | |
18fae2a8 | 1587 | To exit @value{GDBN}, use the @code{quit} command (abbreviated @code{q}), or type |
e251e767 | 1588 | an end-of-file character (usually @kbd{C-d}). |
70b88761 RP |
1589 | @end table |
1590 | ||
1591 | @cindex interrupt | |
18fae2a8 RP |
1592 | An interrupt (often @kbd{C-c}) will not exit from @value{GDBN}, but rather |
1593 | will terminate the action of any @value{GDBN} command that is in progress and | |
1594 | return to @value{GDBN} command level. It is safe to type the interrupt | |
1595 | character at any time because @value{GDBN} does not allow it to take effect | |
70b88761 RP |
1596 | until a time when it is safe. |
1597 | ||
18fae2a8 | 1598 | @ifclear BARETARGET |
ed447b95 RP |
1599 | If you have been using @value{GDBN} to control an attached process or |
1600 | device, you can release it with the @code{detach} command | |
1601 | (@pxref{Attach, ,Debugging an Already-Running Process}). | |
18fae2a8 | 1602 | @end ifclear |
70b88761 | 1603 | |
18fae2a8 | 1604 | @ifclear BARETARGET |
4eb4cf57 | 1605 | @node Shell Commands |
70b88761 | 1606 | @section Shell Commands |
1041a570 | 1607 | |
70b88761 | 1608 | If you need to execute occasional shell commands during your |
18fae2a8 | 1609 | debugging session, there is no need to leave or suspend @value{GDBN}; you can |
70b88761 RP |
1610 | just use the @code{shell} command. |
1611 | ||
1612 | @table @code | |
1613 | @item shell @var{command string} | |
1614 | @kindex shell | |
1615 | @cindex shell escape | |
18fae2a8 | 1616 | Directs @value{GDBN} to invoke an inferior shell to execute @var{command |
70b88761 | 1617 | string}. If it exists, the environment variable @code{SHELL} is used |
18fae2a8 | 1618 | for the name of the shell to run. Otherwise @value{GDBN} uses |
70b88761 RP |
1619 | @code{/bin/sh}. |
1620 | @end table | |
1621 | ||
1622 | The utility @code{make} is often needed in development environments. | |
18fae2a8 | 1623 | You do not have to use the @code{shell} command for this purpose in @value{GDBN}: |
70b88761 RP |
1624 | |
1625 | @table @code | |
1626 | @item make @var{make-args} | |
1627 | @kindex make | |
1628 | @cindex calling make | |
18fae2a8 | 1629 | Causes @value{GDBN} to execute an inferior @code{make} program with the specified |
70b88761 RP |
1630 | arguments. This is equivalent to @samp{shell make @var{make-args}}. |
1631 | @end table | |
18fae2a8 | 1632 | @end ifclear |
70b88761 | 1633 | |
4eb4cf57 | 1634 | @node Commands |
18fae2a8 | 1635 | @chapter @value{GDBN} Commands |
70b88761 | 1636 | |
18fae2a8 | 1637 | You can abbreviate a @value{GDBN} command to the first few letters of the command |
6f3ec223 | 1638 | name, if that abbreviation is unambiguous; and you can repeat certain |
18fae2a8 RP |
1639 | @value{GDBN} commands by typing just @key{RET}. You can also use the @key{TAB} |
1640 | key to get @value{GDBN} to fill out the rest of a word in a command (or to | |
6f3ec223 | 1641 | show you the alternatives available, if there's more than one possibility). |
29a2b744 | 1642 | |
70b88761 | 1643 | @menu |
ed447b95 RP |
1644 | * Command Syntax:: How to give commands to @value{GDBN} |
1645 | * Completion:: Command completion | |
1646 | * Help:: How to ask @value{GDBN} for help | |
70b88761 RP |
1647 | @end menu |
1648 | ||
4eb4cf57 | 1649 | @node Command Syntax |
70b88761 | 1650 | @section Command Syntax |
1041a570 | 1651 | |
18fae2a8 | 1652 | A @value{GDBN} command is a single line of input. There is no limit on how long |
70b88761 RP |
1653 | it can be. It starts with a command name, which is followed by arguments |
1654 | whose meaning depends on the command name. For example, the command | |
1655 | @code{step} accepts an argument which is the number of times to step, | |
1656 | as in @samp{step 5}. You can also use the @code{step} command with | |
1657 | no arguments. Some command names do not allow any arguments. | |
1658 | ||
1659 | @cindex abbreviation | |
18fae2a8 | 1660 | @value{GDBN} command names may always be truncated if that abbreviation is |
70b88761 RP |
1661 | unambiguous. Other possible command abbreviations are listed in the |
1662 | documentation for individual commands. In some cases, even ambiguous | |
1663 | abbreviations are allowed; for example, @code{s} is specially defined as | |
1664 | equivalent to @code{step} even though there are other commands whose | |
1665 | names start with @code{s}. You can test abbreviations by using them as | |
7463aadd | 1666 | arguments to the @code{help} command. |
70b88761 | 1667 | |
e251e767 | 1668 | @cindex repeating commands |
70b88761 | 1669 | @kindex RET |
18fae2a8 | 1670 | A blank line as input to @value{GDBN} (typing just @key{RET}) means to |
70b88761 RP |
1671 | repeat the previous command. Certain commands (for example, @code{run}) |
1672 | will not repeat this way; these are commands for which unintentional | |
1673 | repetition might cause trouble and which you are unlikely to want to | |
1674 | repeat. | |
1675 | ||
1676 | The @code{list} and @code{x} commands, when you repeat them with | |
1677 | @key{RET}, construct new arguments rather than repeating | |
1678 | exactly as typed. This permits easy scanning of source or memory. | |
1679 | ||
18fae2a8 | 1680 | @value{GDBN} can also use @key{RET} in another way: to partition lengthy |
b80282d5 | 1681 | output, in a way similar to the common utility @code{more} |
29a2b744 | 1682 | (@pxref{Screen Size}). Since it is easy to press one @key{RET} too many |
18fae2a8 | 1683 | in this situation, @value{GDBN} disables command repetition after any command |
b80282d5 RP |
1684 | that generates this sort of display. |
1685 | ||
70b88761 RP |
1686 | @kindex # |
1687 | @cindex comment | |
1688 | A line of input starting with @kbd{#} is a comment; it does nothing. | |
29a2b744 | 1689 | This is useful mainly in command files (@pxref{Command Files}). |
70b88761 | 1690 | |
4eb4cf57 | 1691 | @node Completion |
6f3ec223 RP |
1692 | @section Command Completion |
1693 | ||
1694 | @cindex completion | |
1695 | @cindex word completion | |
18fae2a8 | 1696 | @value{GDBN} can fill in the rest of a word in a command for you, if there's |
6f3ec223 | 1697 | only one possibility; it can also show you what the valid possibilities |
18fae2a8 RP |
1698 | are for the next word in a command, at any time. This works for @value{GDBN} |
1699 | commands, @value{GDBN} subcommands, and the names of symbols in your program. | |
6f3ec223 | 1700 | |
18fae2a8 RP |
1701 | Press the @key{TAB} key whenever you want @value{GDBN} to fill out the rest |
1702 | of a word. If there's only one possibility, @value{GDBN} will fill in the | |
6f3ec223 RP |
1703 | word, and wait for you to finish the command (or press @key{RET} to |
1704 | enter it). For example, if you type | |
1705 | ||
0fdc6e27 RP |
1706 | @c FIXME "@key" doesn't distinguish its argument sufficiently to permit |
1707 | @c complete accuracy in these examples; space introduced for clarity. | |
1708 | @c If texinfo enhancements make it unnecessary, it would be nice to | |
1709 | @c replace " @key" by "@key" in the following... | |
6f3ec223 | 1710 | @example |
18fae2a8 | 1711 | (@value{GDBP}) info bre @key{TAB} |
6f3ec223 RP |
1712 | @end example |
1713 | ||
1714 | @noindent | |
18fae2a8 | 1715 | @value{GDBN} fills in the rest of the word @samp{breakpoints}, since that's |
6f3ec223 RP |
1716 | the only @code{info} subcommand beginning with @samp{bre}: |
1717 | ||
1718 | @example | |
18fae2a8 | 1719 | (@value{GDBP}) info breakpoints |
6f3ec223 RP |
1720 | @end example |
1721 | ||
1722 | @noindent | |
1723 | You can either press @key{RET} at this point, to run the @code{info | |
1724 | breakpoints} command, or backspace and enter something else, if | |
1725 | @samp{breakpoints} doesn't look like the command you expected. (If you | |
1726 | were sure you wanted @code{info breakpoints} in the first place, you | |
1727 | might as well just type @key{RET} immediately after @samp{info bre}, | |
1728 | to exploit command abbreviations rather than command completion). | |
1729 | ||
1730 | If there is more than one possibility for the next word when you press | |
18fae2a8 | 1731 | @key{TAB}, @value{GDBN} will sound a bell. You can either supply more |
6f3ec223 | 1732 | characters and try again, or just press @key{TAB} a second time, and |
18fae2a8 | 1733 | @value{GDBN} will display all the possible completions for that word. For |
6f3ec223 | 1734 | example, you might want to set a breakpoint on a subroutine whose name |
18fae2a8 | 1735 | begins with @samp{make_}, but when you type @kbd{b make_@key{TAB}} @value{GDBN} |
6f3ec223 RP |
1736 | just sounds the bell. Typing @key{TAB} again will display all the |
1737 | function names in your program that begin with those characters, for | |
1738 | example: | |
1739 | ||
1740 | @example | |
18fae2a8 RP |
1741 | (@value{GDBP}) b make_ @key{TAB} |
1742 | @exdent @value{GDBN} sounds bell; press @key{TAB} again, to see: | |
6f3ec223 RP |
1743 | make_a_section_from_file make_environ |
1744 | make_abs_section make_function_type | |
1745 | make_blockvector make_pointer_type | |
1746 | make_cleanup make_reference_type | |
1747 | make_command make_symbol_completion_list | |
18fae2a8 | 1748 | (@value{GDBP}) b make_ |
6f3ec223 RP |
1749 | @end example |
1750 | ||
1751 | @noindent | |
18fae2a8 | 1752 | After displaying the available possibilities, @value{GDBN} copies your |
b1385986 | 1753 | partial input (@samp{b make_} in the example) so you can finish the |
6f3ec223 RP |
1754 | command. |
1755 | ||
1756 | If you just want to see the list of alternatives in the first place, you | |
b1385986 | 1757 | can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?} |
0f153e74 | 1758 | means @kbd{@key{META} ?}. You can type this |
18fae2a8 | 1759 | @ifclear DOSHOST |
0f153e74 | 1760 | either by holding down a |
b1385986 | 1761 | key designated as the @key{META} shift on your keyboard (if there is |
0f153e74 | 1762 | one) while typing @kbd{?}, or |
18fae2a8 | 1763 | @end ifclear |
0f153e74 | 1764 | as @key{ESC} followed by @kbd{?}. |
6f3ec223 RP |
1765 | |
1766 | @cindex quotes in commands | |
1767 | @cindex completion of quoted strings | |
1768 | Sometimes the string you need, while logically a ``word'', may contain | |
18fae2a8 | 1769 | parentheses or other characters that @value{GDBN} normally excludes from its |
6f3ec223 | 1770 | notion of a word. To permit word completion to work in this situation, |
18fae2a8 | 1771 | you may enclose words in @code{'} (single quote marks) in @value{GDBN} commands. |
6f3ec223 RP |
1772 | |
1773 | The most likely situation where you might need this is in typing the | |
1774 | name of a C++ function. This is because C++ allows function overloading | |
1775 | (multiple definitions of the same function, distinguished by argument | |
b1385986 RP |
1776 | type). For example, when you want to set a breakpoint you may need to |
1777 | distinguish whether you mean the version of @code{name} that takes an | |
1778 | @code{int} parameter, @code{name(int)}, or the version that takes a | |
1779 | @code{float} parameter, @code{name(float)}. To use the word-completion | |
1780 | facilities in this situation, type a single quote @code{'} at the | |
18fae2a8 | 1781 | beginning of the function name. This alerts @value{GDBN} that it may need to |
b1385986 RP |
1782 | consider more information than usual when you press @key{TAB} or |
1783 | @kbd{M-?} to request word completion: | |
6f3ec223 RP |
1784 | |
1785 | @example | |
18fae2a8 | 1786 | (@value{GDBP}) b 'bubble( @key{M-?} |
0fdc6e27 | 1787 | bubble(double,double) bubble(int,int) |
18fae2a8 | 1788 | (@value{GDBP}) b 'bubble( |
6f3ec223 RP |
1789 | @end example |
1790 | ||
18fae2a8 RP |
1791 | In some cases, @value{GDBN} can tell that completing a name will require |
1792 | quotes. When this happens, @value{GDBN} will insert the quote for you (while | |
0fdc6e27 RP |
1793 | completing as much as it can) if you do not type the quote in the first |
1794 | place: | |
1795 | ||
1796 | @example | |
18fae2a8 RP |
1797 | (@value{GDBP}) b bub @key{TAB} |
1798 | @exdent @value{GDBN} alters your input line to the following, and rings a bell: | |
1799 | (@value{GDBP}) b 'bubble( | |
0fdc6e27 RP |
1800 | @end example |
1801 | ||
1802 | @noindent | |
18fae2a8 | 1803 | In general, @value{GDBN} can tell that a quote is needed (and inserts it) if |
0fdc6e27 RP |
1804 | you have not yet started typing the argument list when you ask for |
1805 | completion on an overloaded symbol. | |
1806 | ||
1807 | ||
4eb4cf57 | 1808 | @node Help |
70b88761 RP |
1809 | @section Getting Help |
1810 | @cindex online documentation | |
1811 | @kindex help | |
1041a570 | 1812 | |
18fae2a8 | 1813 | You can always ask @value{GDBN} itself for information on its commands, using the |
e251e767 | 1814 | command @code{help}. |
70b88761 RP |
1815 | |
1816 | @table @code | |
1817 | @item help | |
1818 | @itemx h | |
1819 | @kindex h | |
1820 | You can use @code{help} (abbreviated @code{h}) with no arguments to | |
1821 | display a short list of named classes of commands: | |
1041a570 | 1822 | |
70b88761 | 1823 | @smallexample |
18fae2a8 | 1824 | (@value{GDBP}) help |
70b88761 RP |
1825 | List of classes of commands: |
1826 | ||
1827 | running -- Running the program | |
1828 | stack -- Examining the stack | |
1829 | data -- Examining data | |
1830 | breakpoints -- Making program stop at certain points | |
1831 | files -- Specifying and examining files | |
1832 | status -- Status inquiries | |
1833 | support -- Support facilities | |
1834 | user-defined -- User-defined commands | |
1835 | aliases -- Aliases of other commands | |
1836 | obscure -- Obscure features | |
1837 | ||
203eea5d RP |
1838 | Type "help" followed by a class name for a list of |
1839 | commands in that class. | |
1840 | Type "help" followed by command name for full | |
1841 | documentation. | |
70b88761 | 1842 | Command name abbreviations are allowed if unambiguous. |
18fae2a8 | 1843 | (@value{GDBP}) |
70b88761 RP |
1844 | @end smallexample |
1845 | ||
1846 | @item help @var{class} | |
1847 | Using one of the general help classes as an argument, you can get a | |
1848 | list of the individual commands in that class. For example, here is the | |
1849 | help display for the class @code{status}: | |
1041a570 | 1850 | |
70b88761 | 1851 | @smallexample |
18fae2a8 | 1852 | (@value{GDBP}) help status |
70b88761 RP |
1853 | Status inquiries. |
1854 | ||
1855 | List of commands: | |
1856 | ||
1857 | show -- Generic command for showing things set with "set" | |
1858 | info -- Generic command for printing status | |
1859 | ||
203eea5d RP |
1860 | Type "help" followed by command name for full |
1861 | documentation. | |
70b88761 | 1862 | Command name abbreviations are allowed if unambiguous. |
18fae2a8 | 1863 | (@value{GDBP}) |
70b88761 RP |
1864 | @end smallexample |
1865 | ||
1866 | @item help @var{command} | |
18fae2a8 | 1867 | With a command name as @code{help} argument, @value{GDBN} will display a |
e251e767 | 1868 | short paragraph on how to use that command. |
70b88761 RP |
1869 | @end table |
1870 | ||
18fae2a8 | 1871 | In addition to @code{help}, you can use the @value{GDBN} commands @code{info} |
70b88761 | 1872 | and @code{show} to inquire about the state of your program, or the state |
18fae2a8 | 1873 | of @value{GDBN} itself. Each command supports many topics of inquiry; this |
70b88761 RP |
1874 | manual introduces each of them in the appropriate context. The listings |
1875 | under @code{info} and under @code{show} in the Index point to | |
29a2b744 | 1876 | all the sub-commands. @xref{Index}. |
70b88761 RP |
1877 | |
1878 | @c @group | |
1879 | @table @code | |
1880 | @item info | |
1881 | @kindex info | |
1882 | @kindex i | |
1883 | This command (abbreviated @code{i}) is for describing the state of your | |
ed447b95 RP |
1884 | program. For example, you can list the arguments given to your program |
1885 | with @code{info args}, list the registers currently in use with @code{info | |
1886 | registers}, or list the breakpoints you have set with @code{info breakpoints}. | |
70b88761 RP |
1887 | You can get a complete list of the @code{info} sub-commands with |
1888 | @w{@code{help info}}. | |
1889 | ||
1890 | @kindex show | |
1891 | @item show | |
18fae2a8 | 1892 | In contrast, @code{show} is for describing the state of @value{GDBN} itself. |
70b88761 RP |
1893 | You can change most of the things you can @code{show}, by using the |
1894 | related command @code{set}; for example, you can control what number | |
1895 | system is used for displays with @code{set radix}, or simply inquire | |
e251e767 | 1896 | which is currently in use with @code{show radix}. |
70b88761 RP |
1897 | |
1898 | @kindex info set | |
1899 | To display all the settable parameters and their current | |
1900 | values, you can use @code{show} with no arguments; you may also use | |
1901 | @code{info set}. Both commands produce the same display. | |
1902 | @c FIXME: "info set" violates the rule that "info" is for state of | |
1903 | @c FIXME...program. Ck w/ GNU: "info set" to be called something else, | |
1904 | @c FIXME...or change desc of rule---eg "state of prog and debugging session"? | |
1905 | @end table | |
1906 | @c @end group | |
1907 | ||
1908 | Here are three miscellaneous @code{show} subcommands, all of which are | |
1909 | exceptional in lacking corresponding @code{set} commands: | |
1910 | ||
1911 | @table @code | |
1912 | @kindex show version | |
3d3ab540 | 1913 | @cindex version number |
70b88761 | 1914 | @item show version |
18fae2a8 RP |
1915 | Show what version of @value{GDBN} is running. You should include this |
1916 | information in @value{GDBN} bug-reports. If multiple versions of @value{GDBN} are in | |
ed447b95 | 1917 | use at your site, you may occasionally want to determine which version |
18fae2a8 | 1918 | of @value{GDBN} you are running; as @value{GDBN} evolves, new commands are introduced, |
1041a570 | 1919 | and old ones may wither away. The version number is also announced |
18fae2a8 | 1920 | when you start @value{GDBN} with no arguments. |
70b88761 RP |
1921 | |
1922 | @kindex show copying | |
1923 | @item show copying | |
18fae2a8 | 1924 | Display information about permission for copying @value{GDBN}. |
70b88761 RP |
1925 | |
1926 | @kindex show warranty | |
1927 | @item show warranty | |
1928 | Display the GNU ``NO WARRANTY'' statement. | |
1929 | @end table | |
1930 | ||
4eb4cf57 | 1931 | @node Running |
18fae2a8 | 1932 | @chapter Running Programs Under @value{GDBN} |
70b88761 | 1933 | |
ed447b95 RP |
1934 | When you run a program under @value{GDBN}, you must first generate |
1935 | debugging information when you compile it. You may start it with its | |
1936 | arguments, if any, in an environment of your choice. You may redirect | |
1937 | your program's input and output, debug an already running process, or | |
1938 | kill a child process. | |
1041a570 | 1939 | |
18fae2a8 RP |
1940 | @ignore |
1941 | @c pre-unfolding: | |
70b88761 | 1942 | @menu |
ed447b95 RP |
1943 | * Compilation:: Compiling for debugging |
1944 | * Starting:: Starting your program | |
18fae2a8 | 1945 | @ifclear BARETARGET |
ed447b95 RP |
1946 | * Arguments:: Your program's arguments |
1947 | * Environment:: Your program's environment | |
1948 | * Working Directory:: Your program's working directory | |
1949 | * Input/Output:: Your program's input and output | |
1950 | * Attach:: Debugging an already-running process | |
1951 | * Kill Process:: Killing the child process | |
1952 | * Process Information:: Additional process information | |
18fae2a8 | 1953 | @end ifclear |
70b88761 | 1954 | @end menu |
18fae2a8 RP |
1955 | @end ignore |
1956 | ||
1957 | @ifclear BARETARGET | |
1958 | @menu | |
ed447b95 RP |
1959 | * Compilation:: Compiling for debugging |
1960 | * Starting:: Starting your program | |
1961 | * Arguments:: Your program's arguments | |
1962 | * Environment:: Your program's environment | |
1963 | * Working Directory:: Your program's working directory | |
1964 | * Input/Output:: Your program's input and output | |
1965 | * Attach:: Debugging an already-running process | |
1966 | * Kill Process:: Killing the child process | |
1967 | * Process Information:: Additional process information | |
18fae2a8 RP |
1968 | @end menu |
1969 | @end ifclear | |
1970 | ||
1971 | @ifset BARETARGET | |
1972 | @menu | |
ed447b95 RP |
1973 | * Compilation:: Compiling for debugging |
1974 | * Starting:: Starting your program | |
18fae2a8 RP |
1975 | @end menu |
1976 | @end ifset | |
70b88761 | 1977 | |
4eb4cf57 | 1978 | @node Compilation |
70b88761 RP |
1979 | @section Compiling for Debugging |
1980 | ||
1981 | In order to debug a program effectively, you need to generate | |
1982 | debugging information when you compile it. This debugging information | |
1983 | is stored in the object file; it describes the data type of each | |
1984 | variable or function and the correspondence between source line numbers | |
1985 | and addresses in the executable code. | |
1986 | ||
1987 | To request debugging information, specify the @samp{-g} option when you run | |
1988 | the compiler. | |
1989 | ||
1990 | Many C compilers are unable to handle the @samp{-g} and @samp{-O} | |
1991 | options together. Using those compilers, you cannot generate optimized | |
1992 | executables containing debugging information. | |
1993 | ||
18fae2a8 | 1994 | @value{NGCC}, the GNU C compiler, supports @samp{-g} with or without |
c7cb8acb RP |
1995 | @samp{-O}, making it possible to debug optimized code. We recommend |
1996 | that you @emph{always} use @samp{-g} whenever you compile a program. | |
1997 | You may think your program is correct, but there is no sense in pushing | |
1998 | your luck. | |
70b88761 | 1999 | |
6ca72cc6 RP |
2000 | @cindex optimized code, debugging |
2001 | @cindex debugging optimized code | |
2002 | When you debug a program compiled with @samp{-g -O}, remember that the | |
2003 | optimizer is rearranging your code; the debugger will show you what's | |
2004 | really there. Don't be too surprised when the execution path doesn't | |
2005 | exactly match your source file! An extreme example: if you define a | |
18fae2a8 | 2006 | variable, but never use it, @value{GDBN} will never see that |
6ca72cc6 RP |
2007 | variable---because the compiler optimizes it out of existence. |
2008 | ||
70b88761 RP |
2009 | Some things do not work as well with @samp{-g -O} as with just |
2010 | @samp{-g}, particularly on machines with instruction scheduling. If in | |
2011 | doubt, recompile with @samp{-g} alone, and if this fixes the problem, | |
2012 | please report it as a bug (including a test case!). | |
2013 | ||
2014 | Older versions of the GNU C compiler permitted a variant option | |
18fae2a8 | 2015 | @w{@samp{-gg}} for debugging information. @value{GDBN} no longer supports this |
70b88761 RP |
2016 | format; if your GNU C compiler has this option, do not use it. |
2017 | ||
2018 | @ignore | |
18fae2a8 | 2019 | @comment As far as I know, there are no cases in which @value{GDBN} will |
70b88761 RP |
2020 | @comment produce strange output in this case. (but no promises). |
2021 | If your program includes archives made with the @code{ar} program, and | |
2022 | if the object files used as input to @code{ar} were compiled without the | |
18fae2a8 | 2023 | @samp{-g} option and have names longer than 15 characters, @value{GDBN} will get |
29a2b744 | 2024 | confused reading your program's symbol table. No error message will be |
18fae2a8 | 2025 | given, but @value{GDBN} may behave strangely. The reason for this problem is a |
70b88761 RP |
2026 | deficiency in the Unix archive file format, which cannot represent file |
2027 | names longer than 15 characters. | |
2028 | ||
2029 | To avoid this problem, compile the archive members with the @samp{-g} | |
2030 | option or use shorter file names. Alternatively, use a version of GNU | |
2031 | @code{ar} dated more recently than August 1989. | |
2032 | @end ignore | |
2033 | ||
4eb4cf57 | 2034 | @node Starting |
70b88761 RP |
2035 | @section Starting your Program |
2036 | @cindex starting | |
2037 | @cindex running | |
1041a570 | 2038 | |
70b88761 RP |
2039 | @table @code |
2040 | @item run | |
2041 | @itemx r | |
2042 | @kindex run | |
18fae2a8 | 2043 | Use the @code{run} command to start your program under @value{GDBN}. You must |
1041a570 | 2044 | first specify the program name |
18fae2a8 | 2045 | @ifset VXWORKS |
7463aadd | 2046 | (except on VxWorks) |
18fae2a8 | 2047 | @end ifset |
ed447b95 RP |
2048 | with an argument to @value{GDBN} (@pxref{Invocation, ,Getting In and |
2049 | Out of @value{GDBN}}), or by using the @code{file} or @code{exec-file} | |
2050 | command (@pxref{Files, ,Commands to Specify Files}). | |
1041a570 | 2051 | |
70b88761 RP |
2052 | @end table |
2053 | ||
18fae2a8 | 2054 | @ifclear BARETARGET |
29a2b744 RP |
2055 | If you are running your program in an execution environment that |
2056 | supports processes, @code{run} creates an inferior process and makes | |
2057 | that process run your program. (In environments without processes, | |
2058 | @code{run} jumps to the start of your program.) | |
70b88761 RP |
2059 | |
2060 | The execution of a program is affected by certain information it | |
18fae2a8 | 2061 | receives from its superior. @value{GDBN} provides ways to specify this |
6ca72cc6 | 2062 | information, which you must do @emph{before} starting your program. (You |
29a2b744 RP |
2063 | can change it after starting your program, but such changes will only affect |
2064 | your program the next time you start it.) This information may be | |
70b88761 RP |
2065 | divided into four categories: |
2066 | ||
2067 | @table @asis | |
6ca72cc6 | 2068 | @item The @emph{arguments.} |
29a2b744 | 2069 | Specify the arguments to give your program as the arguments of the |
1041a570 RP |
2070 | @code{run} command. If a shell is available on your target, the shell |
2071 | is used to pass the arguments, so that you may use normal conventions | |
2072 | (such as wildcard expansion or variable substitution) in describing | |
2073 | the arguments. In Unix systems, you can control which shell is used | |
2074 | with the @code{SHELL} environment variable. @xref{Arguments, ,Your | |
2075 | Program's Arguments}. | |
70b88761 | 2076 | |
6ca72cc6 | 2077 | @item The @emph{environment.} |
18fae2a8 RP |
2078 | Your program normally inherits its environment from @value{GDBN}, but you can |
2079 | use the @value{GDBN} commands @code{set environment} and @code{unset | |
70b88761 | 2080 | environment} to change parts of the environment that will be given to |
1041a570 | 2081 | your program. @xref{Environment, ,Your Program's Environment}. |
70b88761 | 2082 | |
6ca72cc6 | 2083 | @item The @emph{working directory.} |
18fae2a8 RP |
2084 | Your program inherits its working directory from @value{GDBN}. You can set |
2085 | @value{GDBN}'s working directory with the @code{cd} command in @value{GDBN}. | |
29a2b744 | 2086 | @xref{Working Directory, ,Your Program's Working Directory}. |
70b88761 | 2087 | |
6ca72cc6 | 2088 | @item The @emph{standard input and output.} |
70b88761 | 2089 | Your program normally uses the same device for standard input and |
18fae2a8 | 2090 | standard output as @value{GDBN} is using. You can redirect input and output |
70b88761 RP |
2091 | in the @code{run} command line, or you can use the @code{tty} command to |
2092 | set a different device for your program. | |
1041a570 | 2093 | @xref{Input/Output, ,Your Program's Input and Output}. |
3d3ab540 RP |
2094 | |
2095 | @cindex pipes | |
29a2b744 RP |
2096 | @emph{Warning:} While input and output redirection work, you cannot use |
2097 | pipes to pass the output of the program you are debugging to another | |
18fae2a8 | 2098 | program; if you attempt this, @value{GDBN} is likely to wind up debugging the |
3d3ab540 | 2099 | wrong program. |
70b88761 | 2100 | @end table |
18fae2a8 | 2101 | @end ifclear |
70b88761 | 2102 | |
1041a570 | 2103 | When you issue the @code{run} command, your program begins to execute |
4eb4cf57 RP |
2104 | immediately. @xref{Stopping, ,Stopping and Continuing}, for discussion |
2105 | of how to arrange for your program to stop. Once your program has | |
2106 | stopped, you may calls functions in your program, using the @code{print} | |
2107 | or @code{call} commands. @xref{Data, ,Examining Data}. | |
70b88761 | 2108 | |
29a2b744 | 2109 | If the modification time of your symbol file has changed since the |
18fae2a8 RP |
2110 | last time @value{GDBN} read its symbols, @value{GDBN} will discard its symbol table and |
2111 | re-read it. When it does this, @value{GDBN} tries to retain your current | |
1041a570 | 2112 | breakpoints. |
70b88761 | 2113 | |
18fae2a8 | 2114 | @ifclear BARETARGET |
4eb4cf57 | 2115 | @node Arguments |
70b88761 RP |
2116 | @section Your Program's Arguments |
2117 | ||
2118 | @cindex arguments (to your program) | |
2119 | The arguments to your program can be specified by the arguments of the | |
2120 | @code{run} command. They are passed to a shell, which expands wildcard | |
29a2b744 | 2121 | characters and performs redirection of I/O, and thence to your program. |
ed447b95 RP |
2122 | @value{GDBN} uses the shell indicated by your @code{SHELL} environment |
2123 | variable if it exists; otherwise, @value{GDBN} uses @code{/bin/sh}. | |
70b88761 RP |
2124 | |
2125 | @code{run} with no arguments uses the same arguments used by the previous | |
2126 | @code{run}, or those set by the @code{set args} command. | |
2127 | ||
2128 | @kindex set args | |
2129 | @table @code | |
2130 | @item set args | |
2131 | Specify the arguments to be used the next time your program is run. If | |
2132 | @code{set args} has no arguments, @code{run} will execute your program | |
e251e767 | 2133 | with no arguments. Once you have run your program with arguments, |
70b88761 RP |
2134 | using @code{set args} before the next @code{run} is the only way to run |
2135 | it again without arguments. | |
2136 | ||
2137 | @item show args | |
2138 | @kindex show args | |
2139 | Show the arguments to give your program when it is started. | |
2140 | @end table | |
2141 | ||
4eb4cf57 | 2142 | @node Environment |
70b88761 RP |
2143 | @section Your Program's Environment |
2144 | ||
2145 | @cindex environment (of your program) | |
2146 | The @dfn{environment} consists of a set of environment variables and | |
2147 | their values. Environment variables conventionally record such things as | |
2148 | your user name, your home directory, your terminal type, and your search | |
2149 | path for programs to run. Usually you set up environment variables with | |
2150 | the shell and they are inherited by all the other programs you run. When | |
29a2b744 | 2151 | debugging, it can be useful to try running your program with a modified |
18fae2a8 | 2152 | environment without having to start @value{GDBN} over again. |
70b88761 RP |
2153 | |
2154 | @table @code | |
2155 | @item path @var{directory} | |
2156 | @kindex path | |
2157 | Add @var{directory} to the front of the @code{PATH} environment variable | |
18fae2a8 | 2158 | (the search path for executables), for both @value{GDBN} and your program. |
70b88761 RP |
2159 | You may specify several directory names, separated by @samp{:} or |
2160 | whitespace. If @var{directory} is already in the path, it is moved to | |
e251e767 | 2161 | the front, so it will be searched sooner. |
7463aadd RP |
2162 | |
2163 | You can use the string @samp{$cwd} to refer to whatever is the current | |
18fae2a8 | 2164 | working directory at the time @value{GDBN} searches the path. If you use |
7463aadd | 2165 | @samp{.} instead, it refers to the directory where you executed the |
18fae2a8 | 2166 | @code{path} command. @value{GDBN} fills in the current path where needed in |
7463aadd | 2167 | the @var{directory} argument, before adding it to the search path. |
29a2b744 | 2168 | @c 'path' is explicitly nonrepeatable, but RMS points out it is silly to |
70b88761 RP |
2169 | @c document that, since repeating it would be a no-op. |
2170 | ||
2171 | @item show paths | |
2172 | @kindex show paths | |
2173 | Display the list of search paths for executables (the @code{PATH} | |
2174 | environment variable). | |
2175 | ||
2176 | @item show environment @r{[}@var{varname}@r{]} | |
2177 | @kindex show environment | |
2178 | Print the value of environment variable @var{varname} to be given to | |
29a2b744 | 2179 | your program when it starts. If you do not supply @var{varname}, |
70b88761 RP |
2180 | print the names and values of all environment variables to be given to |
2181 | your program. You can abbreviate @code{environment} as @code{env}. | |
2182 | ||
7463aadd | 2183 | @item set environment @var{varname} @r{[}=@r{]} @var{value} |
70b88761 | 2184 | @kindex set environment |
ed447b95 | 2185 | Set environment variable @var{varname} to @var{value}. The value |
18fae2a8 | 2186 | changes for your program only, not for @value{GDBN} itself. @var{value} may |
70b88761 RP |
2187 | be any string; the values of environment variables are just strings, and |
2188 | any interpretation is supplied by your program itself. The @var{value} | |
2189 | parameter is optional; if it is eliminated, the variable is set to a | |
2190 | null value. | |
29a2b744 | 2191 | @c "any string" here does not include leading, trailing |
70b88761 RP |
2192 | @c blanks. Gnu asks: does anyone care? |
2193 | ||
2194 | For example, this command: | |
2195 | ||
2196 | @example | |
2197 | set env USER = foo | |
2198 | @end example | |
2199 | ||
2200 | @noindent | |
2201 | tells a Unix program, when subsequently run, that its user is named | |
2202 | @samp{foo}. (The spaces around @samp{=} are used for clarity here; they | |
2203 | are not actually required.) | |
2204 | ||
2205 | @item unset environment @var{varname} | |
2206 | @kindex unset environment | |
2207 | Remove variable @var{varname} from the environment to be passed to your | |
2208 | program. This is different from @samp{set env @var{varname} =}; | |
2209 | @code{unset environment} removes the variable from the environment, | |
e251e767 | 2210 | rather than assigning it an empty value. |
70b88761 RP |
2211 | @end table |
2212 | ||
4eb4cf57 | 2213 | @node Working Directory |
70b88761 RP |
2214 | @section Your Program's Working Directory |
2215 | ||
2216 | @cindex working directory (of your program) | |
2217 | Each time you start your program with @code{run}, it inherits its | |
18fae2a8 | 2218 | working directory from the current working directory of @value{GDBN}. @value{GDBN}'s |
70b88761 RP |
2219 | working directory is initially whatever it inherited from its parent |
2220 | process (typically the shell), but you can specify a new working | |
18fae2a8 | 2221 | directory in @value{GDBN} with the @code{cd} command. |
70b88761 | 2222 | |
18fae2a8 RP |
2223 | The @value{GDBN} working directory also serves as a default for the commands |
2224 | that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to | |
1041a570 | 2225 | Specify Files}. |
70b88761 RP |
2226 | |
2227 | @table @code | |
2228 | @item cd @var{directory} | |
2229 | @kindex cd | |
18fae2a8 | 2230 | Set @value{GDBN}'s working directory to @var{directory}. |
70b88761 RP |
2231 | |
2232 | @item pwd | |
2233 | @kindex pwd | |
18fae2a8 | 2234 | Print @value{GDBN}'s working directory. |
70b88761 RP |
2235 | @end table |
2236 | ||
4eb4cf57 | 2237 | @node Input/Output |
70b88761 RP |
2238 | @section Your Program's Input and Output |
2239 | ||
2240 | @cindex redirection | |
2241 | @cindex i/o | |
2242 | @cindex terminal | |
18fae2a8 RP |
2243 | By default, the program you run under @value{GDBN} does input and output to |
2244 | the same terminal that @value{GDBN} uses. @value{GDBN} switches the terminal to | |
70b88761 RP |
2245 | its own terminal modes to interact with you, but it records the terminal |
2246 | modes your program was using and switches back to them when you continue | |
2247 | running your program. | |
2248 | ||
2249 | @table @code | |
2250 | @item info terminal | |
2251 | @kindex info terminal | |
18fae2a8 | 2252 | Displays @value{GDBN}'s recorded information about the terminal modes your |
70b88761 RP |
2253 | program is using. |
2254 | @end table | |
2255 | ||
29a2b744 | 2256 | You can redirect your program's input and/or output using shell |
70b88761 RP |
2257 | redirection with the @code{run} command. For example, |
2258 | ||
18fae2a8 | 2259 | @example |
70b88761 | 2260 | run > outfile |
18fae2a8 | 2261 | @end example |
70b88761 RP |
2262 | |
2263 | @noindent | |
29a2b744 | 2264 | starts your program, diverting its output to the file @file{outfile}. |
70b88761 RP |
2265 | |
2266 | @kindex tty | |
2267 | @cindex controlling terminal | |
29a2b744 | 2268 | Another way to specify where your program should do input and output is |
70b88761 RP |
2269 | with the @code{tty} command. This command accepts a file name as |
2270 | argument, and causes this file to be the default for future @code{run} | |
2271 | commands. It also resets the controlling terminal for the child | |
2272 | process, for future @code{run} commands. For example, | |
2273 | ||
2274 | @example | |
2275 | tty /dev/ttyb | |
2276 | @end example | |
2277 | ||
2278 | @noindent | |
2279 | directs that processes started with subsequent @code{run} commands | |
2280 | default to do input and output on the terminal @file{/dev/ttyb} and have | |
2281 | that as their controlling terminal. | |
2282 | ||
2283 | An explicit redirection in @code{run} overrides the @code{tty} command's | |
2284 | effect on the input/output device, but not its effect on the controlling | |
2285 | terminal. | |
2286 | ||
2287 | When you use the @code{tty} command or redirect input in the @code{run} | |
2288 | command, only the input @emph{for your program} is affected. The input | |
18fae2a8 | 2289 | for @value{GDBN} still comes from your terminal. |
70b88761 | 2290 | |
4eb4cf57 | 2291 | @node Attach |
70b88761 RP |
2292 | @section Debugging an Already-Running Process |
2293 | @kindex attach | |
2294 | @cindex attach | |
2295 | ||
2296 | @table @code | |
2297 | @item attach @var{process-id} | |
2298 | This command | |
18fae2a8 | 2299 | attaches to a running process---one that was started outside @value{GDBN}. |
70b88761 RP |
2300 | (@code{info files} will show your active targets.) The command takes as |
2301 | argument a process ID. The usual way to find out the process-id of | |
2302 | a Unix process is with the @code{ps} utility, or with the @samp{jobs -l} | |
e251e767 | 2303 | shell command. |
70b88761 RP |
2304 | |
2305 | @code{attach} will not repeat if you press @key{RET} a second time after | |
2306 | executing the command. | |
2307 | @end table | |
2308 | ||
2309 | To use @code{attach}, you must be debugging in an environment which | |
2310 | supports processes. You must also have permission to send the process a | |
18fae2a8 | 2311 | signal, and it must have the same effective user ID as the @value{GDBN} |
70b88761 RP |
2312 | process. |
2313 | ||
2314 | When using @code{attach}, you should first use the @code{file} command | |
2315 | to specify the program running in the process and load its symbol table. | |
29a2b744 | 2316 | @xref{Files, ,Commands to Specify Files}. |
70b88761 | 2317 | |
18fae2a8 | 2318 | The first thing @value{GDBN} does after arranging to debug the specified |
70b88761 | 2319 | process is to stop it. You can examine and modify an attached process |
18fae2a8 | 2320 | with all the @value{GDBN} commands that are ordinarily available when you start |
70b88761 RP |
2321 | processes with @code{run}. You can insert breakpoints; you can step and |
2322 | continue; you can modify storage. If you would rather the process | |
2323 | continue running, you may use the @code{continue} command after | |
18fae2a8 | 2324 | attaching @value{GDBN} to the process. |
70b88761 RP |
2325 | |
2326 | @table @code | |
2327 | @item detach | |
2328 | @kindex detach | |
2329 | When you have finished debugging the attached process, you can use the | |
18fae2a8 | 2330 | @code{detach} command to release it from @value{GDBN}'s control. Detaching |
70b88761 | 2331 | the process continues its execution. After the @code{detach} command, |
18fae2a8 | 2332 | that process and @value{GDBN} become completely independent once more, and you |
70b88761 RP |
2333 | are ready to @code{attach} another process or start one with @code{run}. |
2334 | @code{detach} will not repeat if you press @key{RET} again after | |
2335 | executing the command. | |
2336 | @end table | |
2337 | ||
18fae2a8 | 2338 | If you exit @value{GDBN} or use the @code{run} command while you have an attached |
70b88761 RP |
2339 | process, you kill that process. By default, you will be asked for |
2340 | confirmation if you try to do either of these things; you can control | |
2341 | whether or not you need to confirm by using the @code{set confirm} command | |
29a2b744 | 2342 | (@pxref{Messages/Warnings, ,Optional Warnings and Messages}). |
70b88761 | 2343 | |
4eb4cf57 | 2344 | @node Kill Process |
70b88761 RP |
2345 | @c @group |
2346 | @section Killing the Child Process | |
2347 | ||
2348 | @table @code | |
2349 | @item kill | |
2350 | @kindex kill | |
18fae2a8 | 2351 | Kill the child process in which your program is running under @value{GDBN}. |
70b88761 RP |
2352 | @end table |
2353 | ||
2354 | This command is useful if you wish to debug a core dump instead of a | |
18fae2a8 | 2355 | running process. @value{GDBN} ignores any core dump file while your program |
70b88761 RP |
2356 | is running. |
2357 | @c @end group | |
2358 | ||
18fae2a8 RP |
2359 | On some operating systems, a program cannot be executed outside @value{GDBN} |
2360 | while you have breakpoints set on it inside @value{GDBN}. You can use the | |
29a2b744 | 2361 | @code{kill} command in this situation to permit running your program |
70b88761 RP |
2362 | outside the debugger. |
2363 | ||
2364 | The @code{kill} command is also useful if you wish to recompile and | |
29a2b744 | 2365 | relink your program, since on many systems it is impossible to modify an |
70b88761 | 2366 | executable file while it is running in a process. In this case, when you |
18fae2a8 | 2367 | next type @code{run}, @value{GDBN} will notice that the file has changed, and |
70b88761 RP |
2368 | will re-read the symbol table (while trying to preserve your current |
2369 | breakpoint settings). | |
2370 | ||
4eb4cf57 | 2371 | @node Process Information |
d24e0922 RP |
2372 | @section Additional Process Information |
2373 | ||
2374 | @kindex /proc | |
2375 | @cindex process image | |
2376 | Some operating systems provide a facility called @samp{/proc} that can | |
cc9bc574 | 2377 | be used to examine the image of a running process using file-system |
18fae2a8 | 2378 | subroutines. If @value{GDBN} is configured for an operating system with this |
cc9bc574 RP |
2379 | facility, the command @code{info proc} is available to report on several |
2380 | kinds of information about the process running your program. | |
d24e0922 RP |
2381 | |
2382 | @table @code | |
2383 | @item info proc | |
2384 | @kindex info proc | |
2385 | Summarize available information about the process. | |
2386 | ||
2387 | @item info proc mappings | |
2388 | @kindex info proc mappings | |
2389 | Report on the address ranges accessible in the program, with information | |
2390 | on whether your program may read, write, or execute each range. | |
2391 | ||
2392 | @item info proc times | |
2393 | @kindex info proc times | |
2394 | Starting time, user CPU time, and system CPU time for your program and | |
2395 | its children. | |
2396 | ||
2397 | @item info proc id | |
2398 | @kindex info proc id | |
2399 | Report on the process ID's related to your program: its own process id, | |
2400 | the id of its parent, the process group id, and the session id. | |
2401 | ||
2402 | @item info proc status | |
2403 | @kindex info proc status | |
2404 | General information on the state of the process. If the process is | |
2405 | stopped, this report includes the reason for stopping, and any signal | |
2406 | received. | |
cc9bc574 RP |
2407 | |
2408 | @item info proc all | |
2409 | Show all the above information about the process. | |
d24e0922 | 2410 | @end table |
18fae2a8 | 2411 | @end ifclear |
d24e0922 | 2412 | |
4eb4cf57 | 2413 | @node Stopping |
70b88761 RP |
2414 | @chapter Stopping and Continuing |
2415 | ||
ed447b95 | 2416 | The principal purposes of using a debugger are so that you can stop your |
29a2b744 | 2417 | program before it terminates; or so that, if your program runs into |
70b88761 RP |
2418 | trouble, you can investigate and find out why. |
2419 | ||
18fae2a8 RP |
2420 | Inside @value{GDBN}, your program may stop for any of several reasons, such |
2421 | as a signal, a breakpoint, or reaching a new line after a @value{GDBN} | |
70b88761 RP |
2422 | command such as @code{step}. You may then examine and change |
2423 | variables, set new breakpoints or remove old ones, and then continue | |
18fae2a8 | 2424 | execution. Usually, the messages shown by @value{GDBN} provide ample |
70b88761 RP |
2425 | explanation of the status of your program---but you can also explicitly |
2426 | request this information at any time. | |
2427 | ||
2428 | @table @code | |
2429 | @item info program | |
2430 | @kindex info program | |
2431 | Display information about the status of your program: whether it is | |
2432 | running or not, what process it is, and why it stopped. | |
2433 | @end table | |
2434 | ||
18fae2a8 RP |
2435 | @ignore |
2436 | @c original menu | |
2437 | @menu | |
2438 | @ifclear CONLY | |
ed447b95 | 2439 | * Breakpoints:: Breakpoints, watchpoints, and exceptions |
18fae2a8 RP |
2440 | @end ifclear |
2441 | @ifset CONLY | |
ed447b95 | 2442 | * Breakpoints:: Breakpoints and watchpoints |
18fae2a8 | 2443 | @end ifset |
ed447b95 | 2444 | * Continuing and Stepping:: Resuming execution |
18fae2a8 RP |
2445 | @ifset POSIX |
2446 | * Signals:: Signals | |
2447 | @end ifset | |
2448 | @end menu | |
2449 | @end ignore | |
2450 | ||
2451 | @c !CONLY && POSIX | |
2452 | @ifclear CONLY | |
2453 | @ifset POSIX | |
70b88761 | 2454 | @menu |
ed447b95 RP |
2455 | * Breakpoints:: Breakpoints, watchpoints, and exceptions |
2456 | * Continuing and Stepping:: Resuming execution | |
18fae2a8 RP |
2457 | * Signals:: Signals |
2458 | @end menu | |
2459 | @end ifset | |
2460 | @end ifclear | |
2461 | ||
2462 | @c CONLY && POSIX | |
2463 | @ifset CONLY | |
2464 | @ifset POSIX | |
2465 | @menu | |
ed447b95 RP |
2466 | * Breakpoints:: Breakpoints and watchpoints |
2467 | * Continuing and Stepping:: Resuming execution | |
b80282d5 | 2468 | * Signals:: Signals |
70b88761 | 2469 | @end menu |
18fae2a8 RP |
2470 | @end ifset |
2471 | @end ifset | |
2472 | ||
2473 | @c !CONLY && !POSIX | |
2474 | @ifclear CONLY | |
2475 | @ifclear POSIX | |
2476 | @menu | |
ed447b95 RP |
2477 | * Breakpoints:: Breakpoints, watchpoints, and exceptions |
2478 | * Continuing and Stepping:: Resuming execution | |
18fae2a8 RP |
2479 | @end menu |
2480 | @end ifclear | |
2481 | @end ifclear | |
2482 | ||
2483 | @c CONLY && !POSIX | |
2484 | @ifset CONLY | |
2485 | @ifclear POSIX | |
2486 | @menu | |
ed447b95 RP |
2487 | * Breakpoints:: Breakpoints and watchpoints |
2488 | * Continuing and Stepping:: Resuming execution | |
18fae2a8 RP |
2489 | @end menu |
2490 | @end ifclear | |
2491 | @end ifset | |
70b88761 | 2492 | |
18fae2a8 RP |
2493 | @c node-defaulting requires adjacency of @node and sectioning cmds |
2494 | @c ...hence distribute @node Breakpoints over two possible @if expansions. | |
2495 | @c | |
2496 | @ifclear CONLY | |
4eb4cf57 | 2497 | @node Breakpoints |
70b88761 | 2498 | @section Breakpoints, Watchpoints, and Exceptions |
18fae2a8 RP |
2499 | @end ifclear |
2500 | @ifset CONLY | |
2501 | @node Breakpoints | |
0f153e74 | 2502 | @section Breakpoints and Watchpoints |
18fae2a8 | 2503 | @end ifset |
70b88761 RP |
2504 | |
2505 | @cindex breakpoints | |
2506 | A @dfn{breakpoint} makes your program stop whenever a certain point in | |
1041a570 | 2507 | the program is reached. For each breakpoint, you can add various |
29a2b744 | 2508 | conditions to control in finer detail whether your program will stop. |
70b88761 | 2509 | You can set breakpoints with the @code{break} command and its variants |
29a2b744 RP |
2510 | (@pxref{Set Breaks, ,Setting Breakpoints}), to specify the place where |
2511 | your program should stop by line number, function name or exact address | |
0f153e74 | 2512 | in the program. |
18fae2a8 | 2513 | @ifclear CONLY |
0f153e74 RP |
2514 | In languages with exception handling (such as GNU C++), you can also set |
2515 | breakpoints where an exception is raised (@pxref{Exception Handling, | |
2516 | ,Breakpoints and Exceptions}). | |
18fae2a8 | 2517 | @end ifclear |
70b88761 RP |
2518 | |
2519 | @cindex watchpoints | |
6ca72cc6 RP |
2520 | @cindex memory tracing |
2521 | @cindex breakpoint on memory address | |
2522 | @cindex breakpoint on variable modification | |
29a2b744 RP |
2523 | A @dfn{watchpoint} is a special breakpoint that stops your program |
2524 | when the value of an expression changes. You must use a different | |
2525 | command to set watchpoints (@pxref{Set Watchpoints, ,Setting | |
2526 | Watchpoints}), but aside from that, you can manage a watchpoint like | |
2527 | any other breakpoint: you enable, disable, and delete both breakpoints | |
1041a570 | 2528 | and watchpoints using the same commands. |
70b88761 | 2529 | |
6ca72cc6 RP |
2530 | @cindex breakpoint numbers |
2531 | @cindex numbers for breakpoints | |
18fae2a8 | 2532 | @value{GDBN} assigns a number to each breakpoint or watchpoint when you |
6ca72cc6 RP |
2533 | create it; these numbers are successive integers starting with one. In |
2534 | many of the commands for controlling various features of breakpoints you | |
2535 | use the breakpoint number to say which breakpoint you want to change. | |
2536 | Each breakpoint may be @dfn{enabled} or @dfn{disabled}; if disabled, it has | |
29a2b744 | 2537 | no effect on your program until you enable it again. |
70b88761 RP |
2538 | |
2539 | @menu | |
ed447b95 RP |
2540 | * Set Breaks:: Setting breakpoints |
2541 | * Set Watchpoints:: Setting watchpoints | |
2542 | * Exception Handling:: Breakpoints and exceptions | |
2543 | * Delete Breaks:: Deleting breakpoints | |
2544 | * Disabling:: Disabling breakpoints | |
2545 | * Conditions:: Break conditions | |
2546 | * Break Commands:: Breakpoint command lists | |
2547 | * Breakpoint Menus:: Breakpoint menus | |
2548 | * Error in Breakpoints:: ``Cannot insert breakpoints'' | |
70b88761 RP |
2549 | @end menu |
2550 | ||
4eb4cf57 | 2551 | @node Set Breaks |
70b88761 RP |
2552 | @subsection Setting Breakpoints |
2553 | ||
4906534f RP |
2554 | @c FIXME LMB what does GDB do if no code on line of breakpt? |
2555 | @c consider in particular declaration with/without initialization. | |
2556 | @c | |
2557 | @c FIXME 2 is there stuff on this already? break at fun start, already init? | |
2558 | ||
70b88761 RP |
2559 | @kindex break |
2560 | @kindex b | |
6ca72cc6 RP |
2561 | @kindex $bpnum |
2562 | @cindex latest breakpoint | |
2563 | Breakpoints are set with the @code{break} command (abbreviated | |
2564 | @code{b}). The debugger convenience variable @samp{$bpnum} records the | |
2565 | number of the beakpoint you've set most recently; see @ref{Convenience | |
d24e0922 | 2566 | Vars,, Convenience Variables}, for a discussion of what you can do with |
6ca72cc6 | 2567 | convenience variables. |
70b88761 RP |
2568 | |
2569 | You have several ways to say where the breakpoint should go. | |
2570 | ||
2571 | @table @code | |
2572 | @item break @var{function} | |
0f153e74 | 2573 | Set a breakpoint at entry to function @var{function}. |
18fae2a8 | 2574 | @ifclear CONLY |
0f153e74 RP |
2575 | When using source languages that permit overloading of symbols, such as |
2576 | C++, @var{function} may refer to more than one possible place to break. | |
70b88761 | 2577 | @xref{Breakpoint Menus}, for a discussion of that situation. |
18fae2a8 | 2578 | @end ifclear |
70b88761 RP |
2579 | |
2580 | @item break +@var{offset} | |
2581 | @itemx break -@var{offset} | |
2582 | Set a breakpoint some number of lines forward or back from the position | |
2583 | at which execution stopped in the currently selected frame. | |
2584 | ||
2585 | @item break @var{linenum} | |
2586 | Set a breakpoint at line @var{linenum} in the current source file. | |
2587 | That file is the last file whose source text was printed. This | |
29a2b744 | 2588 | breakpoint will stop your program just before it executes any of the |
70b88761 RP |
2589 | code on that line. |
2590 | ||
2591 | @item break @var{filename}:@var{linenum} | |
2592 | Set a breakpoint at line @var{linenum} in source file @var{filename}. | |
2593 | ||
2594 | @item break @var{filename}:@var{function} | |
2595 | Set a breakpoint at entry to function @var{function} found in file | |
2596 | @var{filename}. Specifying a file name as well as a function name is | |
2597 | superfluous except when multiple files contain similarly named | |
2598 | functions. | |
2599 | ||
2600 | @item break *@var{address} | |
2601 | Set a breakpoint at address @var{address}. You can use this to set | |
29a2b744 | 2602 | breakpoints in parts of your program which do not have debugging |
70b88761 RP |
2603 | information or source files. |
2604 | ||
2605 | @item break | |
29a2b744 RP |
2606 | When called without any arguments, @code{break} sets a breakpoint at |
2607 | the next instruction to be executed in the selected stack frame | |
2608 | (@pxref{Stack, ,Examining the Stack}). In any selected frame but the | |
2609 | innermost, this will cause your program to stop as soon as control | |
2610 | returns to that frame. This is similar to the effect of a | |
2611 | @code{finish} command in the frame inside the selected frame---except | |
2612 | that @code{finish} does not leave an active breakpoint. If you use | |
18fae2a8 | 2613 | @code{break} without an argument in the innermost frame, @value{GDBN} will stop |
1041a570 RP |
2614 | the next time it reaches the current location; this may be useful |
2615 | inside loops. | |
70b88761 | 2616 | |
18fae2a8 | 2617 | @value{GDBN} normally ignores breakpoints when it resumes execution, until at |
70b88761 RP |
2618 | least one instruction has been executed. If it did not do this, you |
2619 | would be unable to proceed past a breakpoint without first disabling the | |
2620 | breakpoint. This rule applies whether or not the breakpoint already | |
29a2b744 | 2621 | existed when your program stopped. |
70b88761 RP |
2622 | |
2623 | @item break @dots{} if @var{cond} | |
2624 | Set a breakpoint with condition @var{cond}; evaluate the expression | |
2625 | @var{cond} each time the breakpoint is reached, and stop only if the | |
3d3ab540 | 2626 | value is nonzero---that is, if @var{cond} evaluates as true. |
1041a570 RP |
2627 | @samp{@dots{}} stands for one of the possible arguments described |
2628 | above (or no argument) specifying where to break. @xref{Conditions, | |
2629 | ,Break Conditions}, for more information on breakpoint conditions. | |
70b88761 RP |
2630 | |
2631 | @item tbreak @var{args} | |
2632 | @kindex tbreak | |
2633 | Set a breakpoint enabled only for one stop. @var{args} are the | |
2634 | same as for the @code{break} command, and the breakpoint is set in the same | |
29a2b744 RP |
2635 | way, but the breakpoint is automatically disabled after the first time your |
2636 | program stops there. @xref{Disabling, ,Disabling Breakpoints}. | |
70b88761 RP |
2637 | |
2638 | @item rbreak @var{regex} | |
2639 | @kindex rbreak | |
2640 | @cindex regular expression | |
4906534f | 2641 | @c FIXME what kind of regexp? |
70b88761 | 2642 | Set breakpoints on all functions matching the regular expression |
b80282d5 | 2643 | @var{regex}. This command |
70b88761 RP |
2644 | sets an unconditional breakpoint on all matches, printing a list of all |
2645 | breakpoints it set. Once these breakpoints are set, they are treated | |
2646 | just like the breakpoints set with the @code{break} command. They can | |
2647 | be deleted, disabled, made conditional, etc., in the standard ways. | |
2648 | ||
18fae2a8 | 2649 | @ifclear CONLY |
b80282d5 RP |
2650 | When debugging C++ programs, @code{rbreak} is useful for setting |
2651 | breakpoints on overloaded functions that are not members of any special | |
2652 | classes. | |
18fae2a8 | 2653 | @end ifclear |
b80282d5 | 2654 | |
70b88761 | 2655 | @kindex info breakpoints |
c338a2fd | 2656 | @cindex @code{$_} and @code{info breakpoints} |
70b88761 | 2657 | @item info breakpoints @r{[}@var{n}@r{]} |
6ca72cc6 RP |
2658 | @itemx info break @r{[}@var{n}@r{]} |
2659 | @itemx info watchpoints @r{[}@var{n}@r{]} | |
2660 | Print a table of all breakpoints and watchpoints set and not | |
2661 | deleted, with the following columns for each breakpoint: | |
2662 | ||
2663 | @table @emph | |
2664 | @item Breakpoint Numbers | |
2665 | @item Type | |
2666 | Breakpoint or watchpoint. | |
2667 | @item Disposition | |
2668 | Whether the breakpoint is marked to be disabled or deleted when hit. | |
2669 | @item Enabled or Disabled | |
d24e0922 | 2670 | Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints |
6ca72cc6 RP |
2671 | that are not enabled. |
2672 | @item Address | |
2673 | Where the breakpoint is in your program, as a memory address | |
2674 | @item What | |
2675 | Where the breakpoint is in the source for your program, as a file and | |
2676 | line number. | |
2677 | @end table | |
2678 | ||
2679 | @noindent | |
2680 | Breakpoint commands, if any, are listed after the line for the | |
2681 | corresponding breakpoint. | |
2682 | ||
2683 | @noindent | |
2684 | @code{info break} with a breakpoint | |
29a2b744 RP |
2685 | number @var{n} as argument lists only that breakpoint. The |
2686 | convenience variable @code{$_} and the default examining-address for | |
2687 | the @code{x} command are set to the address of the last breakpoint | |
6ca72cc6 | 2688 | listed (@pxref{Memory, ,Examining Memory}). |
1041a570 | 2689 | @end table |
70b88761 | 2690 | |
18fae2a8 | 2691 | @value{GDBN} allows you to set any number of breakpoints at the same place in |
1041a570 RP |
2692 | your program. There is nothing silly or meaningless about this. When |
2693 | the breakpoints are conditional, this is even useful | |
29a2b744 | 2694 | (@pxref{Conditions, ,Break Conditions}). |
70b88761 | 2695 | |
6ca72cc6 | 2696 | @cindex negative breakpoint numbers |
18fae2a8 RP |
2697 | @cindex internal @value{GDBN} breakpoints |
2698 | @value{GDBN} itself sometimes sets breakpoints in your program for special | |
6ca72cc6 RP |
2699 | purposes, such as proper handling of @code{longjmp} (in C programs). |
2700 | These internal breakpoints are assigned negative numbers, starting with | |
5a2c1d85 | 2701 | @code{-1}; @samp{info breakpoints} does not display them. |
d48da190 | 2702 | |
18fae2a8 | 2703 | You can see these breakpoints with the @value{GDBN} maintenance command |
5a2c1d85 | 2704 | @samp{maint info breakpoints}. |
6ca72cc6 RP |
2705 | |
2706 | @table @code | |
d48da190 RP |
2707 | @kindex maint info breakpoints |
2708 | @item maint info breakpoints | |
6ca72cc6 | 2709 | Using the same format as @samp{info breakpoints}, display both the |
18fae2a8 | 2710 | breakpoints you've set explicitly, and those @value{GDBN} is using for |
6ca72cc6 RP |
2711 | internal purposes. Internal breakpoints are shown with negative |
2712 | breakpoint numbers. The type column identifies what kind of breakpoint | |
2713 | is shown: | |
2714 | ||
2715 | @table @code | |
2716 | @item breakpoint | |
2717 | Normal, explicitly set breakpoint. | |
2718 | ||
2719 | @item watchpoint | |
2720 | Normal, explicitly set watchpoint. | |
2721 | ||
2722 | @item longjmp | |
2723 | Internal breakpoint, used to handle correctly stepping through | |
2724 | @code{longjmp} calls. | |
2725 | ||
2726 | @item longjmp resume | |
2727 | Internal breakpoint at the target of a @code{longjmp}. | |
2728 | ||
2729 | @item until | |
18fae2a8 | 2730 | Temporary internal breakpoint used by the @value{GDBN} @code{until} command. |
6ca72cc6 RP |
2731 | |
2732 | @item finish | |
18fae2a8 | 2733 | Temporary internal breakpoint used by the @value{GDBN} @code{finish} command. |
6ca72cc6 RP |
2734 | @end table |
2735 | ||
2736 | @end table | |
2737 | ||
2738 | ||
4eb4cf57 | 2739 | @node Set Watchpoints |
70b88761 RP |
2740 | @subsection Setting Watchpoints |
2741 | @cindex setting watchpoints | |
1041a570 | 2742 | |
70b88761 | 2743 | You can use a watchpoint to stop execution whenever the value of an |
e251e767 | 2744 | expression changes, without having to predict a particular place |
70b88761 RP |
2745 | where this may happen. |
2746 | ||
2747 | Watchpoints currently execute two orders of magnitude more slowly than | |
2748 | other breakpoints, but this can well be worth it to catch errors where | |
2749 | you have no clue what part of your program is the culprit. Some | |
2750 | processors provide special hardware to support watchpoint evaluation; future | |
18fae2a8 | 2751 | releases of @value{GDBN} will use such hardware if it is available. |
70b88761 RP |
2752 | |
2753 | @table @code | |
e251e767 | 2754 | @kindex watch |
70b88761 RP |
2755 | @item watch @var{expr} |
2756 | Set a watchpoint for an expression. | |
2757 | ||
2758 | @kindex info watchpoints | |
2759 | @item info watchpoints | |
6ca72cc6 RP |
2760 | This command prints a list of watchpoints and breakpoints; it is the |
2761 | same as @code{info break}. | |
70b88761 RP |
2762 | @end table |
2763 | ||
4eb4cf57 | 2764 | @node Exception Handling |
70b88761 RP |
2765 | @subsection Breakpoints and Exceptions |
2766 | @cindex exception handlers | |
2767 | ||
b80282d5 | 2768 | Some languages, such as GNU C++, implement exception handling. You can |
18fae2a8 | 2769 | use @value{GDBN} to examine what caused your program to raise an exception, |
29a2b744 | 2770 | and to list the exceptions your program is prepared to handle at a |
70b88761 RP |
2771 | given point in time. |
2772 | ||
2773 | @table @code | |
2774 | @item catch @var{exceptions} | |
2775 | @kindex catch | |
2776 | You can set breakpoints at active exception handlers by using the | |
2777 | @code{catch} command. @var{exceptions} is a list of names of exceptions | |
2778 | to catch. | |
2779 | @end table | |
2780 | ||
29a2b744 RP |
2781 | You can use @code{info catch} to list active exception handlers. |
2782 | @xref{Frame Info, ,Information About a Frame}. | |
70b88761 | 2783 | |
18fae2a8 | 2784 | There are currently some limitations to exception handling in @value{GDBN}. |
70b88761 RP |
2785 | These will be corrected in a future release. |
2786 | ||
2787 | @itemize @bullet | |
2788 | @item | |
18fae2a8 | 2789 | If you call a function interactively, @value{GDBN} normally returns |
70b88761 RP |
2790 | control to you when the function has finished executing. If the call |
2791 | raises an exception, however, the call may bypass the mechanism that | |
29a2b744 | 2792 | returns control to you and cause your program to simply continue |
18fae2a8 | 2793 | running until it hits a breakpoint, catches a signal that @value{GDBN} is |
70b88761 RP |
2794 | listening for, or exits. |
2795 | @item | |
2796 | You cannot raise an exception interactively. | |
2797 | @item | |
2798 | You cannot interactively install an exception handler. | |
2799 | @end itemize | |
2800 | ||
2801 | @cindex raise exceptions | |
2802 | Sometimes @code{catch} is not the best way to debug exception handling: | |
29a2b744 | 2803 | if you need to know exactly where an exception is raised, it is better to |
70b88761 RP |
2804 | stop @emph{before} the exception handler is called, since that way you |
2805 | can see the stack before any unwinding takes place. If you set a | |
2806 | breakpoint in an exception handler instead, it may not be easy to find | |
2807 | out where the exception was raised. | |
2808 | ||
2809 | To stop just before an exception handler is called, you need some | |
b80282d5 | 2810 | knowledge of the implementation. In the case of GNU C++, exceptions are |
70b88761 RP |
2811 | raised by calling a library function named @code{__raise_exception} |
2812 | which has the following ANSI C interface: | |
2813 | ||
2814 | @example | |
b80282d5 | 2815 | /* @var{addr} is where the exception identifier is stored. |
70b88761 RP |
2816 | ID is the exception identifier. */ |
2817 | void __raise_exception (void **@var{addr}, void *@var{id}); | |
2818 | @end example | |
2819 | ||
2820 | @noindent | |
2821 | To make the debugger catch all exceptions before any stack | |
2822 | unwinding takes place, set a breakpoint on @code{__raise_exception} | |
29a2b744 | 2823 | (@pxref{Breakpoints, ,Breakpoints Watchpoints and Exceptions}). |
70b88761 | 2824 | |
29a2b744 RP |
2825 | With a conditional breakpoint (@pxref{Conditions, ,Break Conditions}) |
2826 | that depends on the value of @var{id}, you can stop your program when | |
2827 | a specific exception is raised. You can use multiple conditional | |
2828 | breakpoints to stop your program when any of a number of exceptions are | |
2829 | raised. | |
70b88761 | 2830 | |
4eb4cf57 | 2831 | @node Delete Breaks |
70b88761 RP |
2832 | @subsection Deleting Breakpoints |
2833 | ||
2834 | @cindex clearing breakpoints, watchpoints | |
2835 | @cindex deleting breakpoints, watchpoints | |
2836 | It is often necessary to eliminate a breakpoint or watchpoint once it | |
29a2b744 | 2837 | has done its job and you no longer want your program to stop there. This |
70b88761 RP |
2838 | is called @dfn{deleting} the breakpoint. A breakpoint that has been |
2839 | deleted no longer exists; it is forgotten. | |
2840 | ||
2841 | With the @code{clear} command you can delete breakpoints according to | |
29a2b744 | 2842 | where they are in your program. With the @code{delete} command you can |
70b88761 RP |
2843 | delete individual breakpoints or watchpoints by specifying their |
2844 | breakpoint numbers. | |
2845 | ||
18fae2a8 | 2846 | It is not necessary to delete a breakpoint to proceed past it. @value{GDBN} |
70b88761 RP |
2847 | automatically ignores breakpoints on the first instruction to be executed |
2848 | when you continue execution without changing the execution address. | |
2849 | ||
2850 | @table @code | |
2851 | @item clear | |
2852 | @kindex clear | |
2853 | Delete any breakpoints at the next instruction to be executed in the | |
29a2b744 RP |
2854 | selected stack frame (@pxref{Selection, ,Selecting a Frame}). When |
2855 | the innermost frame is selected, this is a good way to delete a | |
2856 | breakpoint where your program just stopped. | |
70b88761 RP |
2857 | |
2858 | @item clear @var{function} | |
2859 | @itemx clear @var{filename}:@var{function} | |
2860 | Delete any breakpoints set at entry to the function @var{function}. | |
2861 | ||
2862 | @item clear @var{linenum} | |
2863 | @itemx clear @var{filename}:@var{linenum} | |
2864 | Delete any breakpoints set at or within the code of the specified line. | |
2865 | ||
2866 | @item delete @r{[}breakpoints@r{]} @r{[}@var{bnums}@dots{}@r{]} | |
2867 | @cindex delete breakpoints | |
2868 | @kindex delete | |
2869 | @kindex d | |
2870 | Delete the breakpoints or watchpoints of the numbers specified as | |
18fae2a8 | 2871 | arguments. If no argument is specified, delete all breakpoints (@value{GDBN} |
1041a570 | 2872 | asks confirmation, unless you have @code{set confirm off}). You |
70b88761 RP |
2873 | can abbreviate this command as @code{d}. |
2874 | @end table | |
2875 | ||
4eb4cf57 | 2876 | @node Disabling |
70b88761 RP |
2877 | @subsection Disabling Breakpoints |
2878 | ||
2879 | @cindex disabled breakpoints | |
2880 | @cindex enabled breakpoints | |
2881 | Rather than deleting a breakpoint or watchpoint, you might prefer to | |
2882 | @dfn{disable} it. This makes the breakpoint inoperative as if it had | |
2883 | been deleted, but remembers the information on the breakpoint so that | |
2884 | you can @dfn{enable} it again later. | |
2885 | ||
2886 | You disable and enable breakpoints and watchpoints with the | |
2887 | @code{enable} and @code{disable} commands, optionally specifying one or | |
2888 | more breakpoint numbers as arguments. Use @code{info break} or | |
2889 | @code{info watch} to print a list of breakpoints or watchpoints if you | |
29a2b744 | 2890 | do not know which numbers to use. |
70b88761 RP |
2891 | |
2892 | A breakpoint or watchpoint can have any of four different states of | |
2893 | enablement: | |
2894 | ||
2895 | @itemize @bullet | |
2896 | @item | |
29a2b744 | 2897 | Enabled. The breakpoint will stop your program. A breakpoint set |
70b88761 RP |
2898 | with the @code{break} command starts out in this state. |
2899 | @item | |
29a2b744 | 2900 | Disabled. The breakpoint has no effect on your program. |
70b88761 | 2901 | @item |
29a2b744 | 2902 | Enabled once. The breakpoint will stop your program, but |
70b88761 RP |
2903 | when it does so it will become disabled. A breakpoint set |
2904 | with the @code{tbreak} command starts out in this state. | |
2905 | @item | |
29a2b744 | 2906 | Enabled for deletion. The breakpoint will stop your program, but |
70b88761 RP |
2907 | immediately after it does so it will be deleted permanently. |
2908 | @end itemize | |
2909 | ||
2910 | You can use the following commands to enable or disable breakpoints and | |
2911 | watchpoints: | |
2912 | ||
2913 | @table @code | |
2914 | @item disable @r{[}breakpoints@r{]} @r{[}@var{bnums}@dots{}@r{]} | |
2915 | @kindex disable breakpoints | |
2916 | @kindex disable | |
2917 | @kindex dis | |
2918 | Disable the specified breakpoints---or all breakpoints, if none are | |
2919 | listed. A disabled breakpoint has no effect but is not forgotten. All | |
2920 | options such as ignore-counts, conditions and commands are remembered in | |
2921 | case the breakpoint is enabled again later. You may abbreviate | |
2922 | @code{disable} as @code{dis}. | |
2923 | ||
2924 | @item enable @r{[}breakpoints@r{]} @r{[}@var{bnums}@dots{}@r{]} | |
2925 | @kindex enable breakpoints | |
2926 | @kindex enable | |
2927 | Enable the specified breakpoints (or all defined breakpoints). They | |
29a2b744 | 2928 | become effective once again in stopping your program. |
70b88761 RP |
2929 | |
2930 | @item enable @r{[}breakpoints@r{]} once @var{bnums}@dots{} | |
2931 | Enable the specified breakpoints temporarily. Each will be disabled | |
29a2b744 | 2932 | again the next time it stops your program. |
70b88761 RP |
2933 | |
2934 | @item enable @r{[}breakpoints@r{]} delete @var{bnums}@dots{} | |
2935 | Enable the specified breakpoints to work once and then die. Each of | |
29a2b744 | 2936 | the breakpoints will be deleted the next time it stops your program. |
70b88761 RP |
2937 | @end table |
2938 | ||
29a2b744 RP |
2939 | Save for a breakpoint set with @code{tbreak} (@pxref{Set Breaks, |
2940 | ,Setting Breakpoints}), breakpoints that you set are initially | |
2941 | enabled; subsequently, they become disabled or enabled only when you | |
2942 | use one of the commands above. (The command @code{until} can set and | |
2943 | delete a breakpoint of its own, but it will not change the state of | |
98fe4566 | 2944 | your other breakpoints; see @ref{Continuing and Stepping, ,Continuing and Stepping}.) |
70b88761 | 2945 | |
4eb4cf57 | 2946 | @node Conditions |
70b88761 RP |
2947 | @subsection Break Conditions |
2948 | @cindex conditional breakpoints | |
2949 | @cindex breakpoint conditions | |
2950 | ||
4906534f RP |
2951 | @c FIXME what is scope of break condition expr? Context where wanted? |
2952 | @c in particular for a watchpoint? | |
29a2b744 | 2953 | The simplest sort of breakpoint breaks every time your program reaches a |
70b88761 RP |
2954 | specified place. You can also specify a @dfn{condition} for a |
2955 | breakpoint. A condition is just a Boolean expression in your | |
1041a570 RP |
2956 | programming language (@pxref{Expressions, ,Expressions}). A breakpoint with |
2957 | a condition evaluates the expression each time your program reaches it, | |
2958 | and your program stops only if the condition is @emph{true}. | |
3d3ab540 RP |
2959 | |
2960 | This is the converse of using assertions for program validation; in that | |
2961 | situation, you want to stop when the assertion is violated---that is, | |
2962 | when the condition is false. In C, if you want to test an assertion expressed | |
e251e767 | 2963 | by the condition @var{assert}, you should set the condition |
3d3ab540 | 2964 | @samp{! @var{assert}} on the appropriate breakpoint. |
70b88761 RP |
2965 | |
2966 | Conditions are also accepted for watchpoints; you may not need them, | |
2967 | since a watchpoint is inspecting the value of an expression anyhow---but | |
2968 | it might be simpler, say, to just set a watchpoint on a variable name, | |
2969 | and specify a condition that tests whether the new value is an interesting | |
e251e767 | 2970 | one. |
70b88761 | 2971 | |
29a2b744 | 2972 | Break conditions can have side effects, and may even call functions in |
70b88761 | 2973 | your program. This can be useful, for example, to activate functions |
29a2b744 RP |
2974 | that log program progress, or to use your own print functions to |
2975 | format special data structures. The effects are completely predictable | |
2976 | unless there is another enabled breakpoint at the same address. (In | |
18fae2a8 | 2977 | that case, @value{GDBN} might see the other breakpoint first and stop your |
29a2b744 RP |
2978 | program without checking the condition of this one.) Note that |
2979 | breakpoint commands are usually more convenient and flexible for the | |
2980 | purpose of performing side effects when a breakpoint is reached | |
2981 | (@pxref{Break Commands, ,Breakpoint Command Lists}). | |
70b88761 RP |
2982 | |
2983 | Break conditions can be specified when a breakpoint is set, by using | |
29a2b744 RP |
2984 | @samp{if} in the arguments to the @code{break} command. @xref{Set |
2985 | Breaks, ,Setting Breakpoints}. They can also be changed at any time | |
2986 | with the @code{condition} command. The @code{watch} command does not | |
2987 | recognize the @code{if} keyword; @code{condition} is the only way to | |
2988 | impose a further condition on a watchpoint. | |
70b88761 | 2989 | |
e251e767 RP |
2990 | @table @code |
2991 | @item condition @var{bnum} @var{expression} | |
2992 | @kindex condition | |
70b88761 RP |
2993 | Specify @var{expression} as the break condition for breakpoint or |
2994 | watchpoint number @var{bnum}. From now on, this breakpoint will stop | |
29a2b744 | 2995 | your program only if the value of @var{expression} is true (nonzero, in |
18fae2a8 | 2996 | C). When you use @code{condition}, @value{GDBN} checks @var{expression} |
70b88761 | 2997 | immediately for syntactic correctness, and to determine whether symbols |
1041a570 | 2998 | in it have referents in the context of your breakpoint. |
29a2b744 | 2999 | @c FIXME so what does GDB do if there is no referent? Moreover, what |
4906534f | 3000 | @c about watchpoints? |
18fae2a8 | 3001 | @value{GDBN} does |
70b88761 | 3002 | not actually evaluate @var{expression} at the time the @code{condition} |
1041a570 | 3003 | command is given, however. @xref{Expressions, ,Expressions}. |
70b88761 RP |
3004 | |
3005 | @item condition @var{bnum} | |
3006 | Remove the condition from breakpoint number @var{bnum}. It becomes | |
3007 | an ordinary unconditional breakpoint. | |
3008 | @end table | |
3009 | ||
3010 | @cindex ignore count (of breakpoint) | |
3011 | A special case of a breakpoint condition is to stop only when the | |
3012 | breakpoint has been reached a certain number of times. This is so | |
3013 | useful that there is a special way to do it, using the @dfn{ignore | |
3014 | count} of the breakpoint. Every breakpoint has an ignore count, which | |
3015 | is an integer. Most of the time, the ignore count is zero, and | |
29a2b744 | 3016 | therefore has no effect. But if your program reaches a breakpoint whose |
70b88761 RP |
3017 | ignore count is positive, then instead of stopping, it just decrements |
3018 | the ignore count by one and continues. As a result, if the ignore count | |
3019 | value is @var{n}, the breakpoint will not stop the next @var{n} times it | |
3020 | is reached. | |
3021 | ||
3022 | @table @code | |
3023 | @item ignore @var{bnum} @var{count} | |
3024 | @kindex ignore | |
3025 | Set the ignore count of breakpoint number @var{bnum} to @var{count}. | |
3026 | The next @var{count} times the breakpoint is reached, your program's | |
18fae2a8 | 3027 | execution will not stop; other than to decrement the ignore count, @value{GDBN} |
70b88761 RP |
3028 | takes no action. |
3029 | ||
3030 | To make the breakpoint stop the next time it is reached, specify | |
3031 | a count of zero. | |
3032 | ||
3033 | @item continue @var{count} | |
3034 | @itemx c @var{count} | |
3035 | @itemx fg @var{count} | |
3036 | @kindex continue @var{count} | |
29a2b744 RP |
3037 | Continue execution of your program, setting the ignore count of the |
3038 | breakpoint where your program stopped to @var{count} minus one. | |
3039 | Thus, your program will not stop at this breakpoint until the | |
70b88761 RP |
3040 | @var{count}'th time it is reached. |
3041 | ||
29a2b744 | 3042 | An argument to this command is meaningful only when your program stopped |
70b88761 RP |
3043 | due to a breakpoint. At other times, the argument to @code{continue} is |
3044 | ignored. | |
3045 | ||
3046 | The synonym @code{fg} is provided purely for convenience, and has | |
3047 | exactly the same behavior as other forms of the command. | |
3048 | @end table | |
3049 | ||
3050 | If a breakpoint has a positive ignore count and a condition, the condition | |
3051 | is not checked. Once the ignore count reaches zero, the condition will | |
3052 | be checked. | |
3053 | ||
29a2b744 | 3054 | You could achieve the effect of the ignore count with a condition such |
18fae2a8 | 3055 | as @w{@samp{$foo-- <= 0}} using a debugger convenience variable that |
1041a570 RP |
3056 | is decremented each time. @xref{Convenience Vars, ,Convenience |
3057 | Variables}. | |
70b88761 | 3058 | |
4eb4cf57 | 3059 | @node Break Commands |
70b88761 RP |
3060 | @subsection Breakpoint Command Lists |
3061 | ||
3062 | @cindex breakpoint commands | |
3063 | You can give any breakpoint (or watchpoint) a series of commands to | |
29a2b744 | 3064 | execute when your program stops due to that breakpoint. For example, you |
70b88761 RP |
3065 | might want to print the values of certain expressions, or enable other |
3066 | breakpoints. | |
3067 | ||
3068 | @table @code | |
3069 | @item commands @r{[}@var{bnum}@r{]} | |
3070 | @itemx @dots{} @var{command-list} @dots{} | |
3071 | @itemx end | |
3072 | @kindex commands | |
3073 | @kindex end | |
3074 | Specify a list of commands for breakpoint number @var{bnum}. The commands | |
3075 | themselves appear on the following lines. Type a line containing just | |
3076 | @code{end} to terminate the commands. | |
3077 | ||
203eea5d RP |
3078 | To remove all commands from a breakpoint, type @code{commands} and |
3079 | follow it immediately with @code{end}; that is, give no commands. | |
70b88761 RP |
3080 | |
3081 | With no @var{bnum} argument, @code{commands} refers to the last | |
3082 | breakpoint or watchpoint set (not to the breakpoint most recently | |
3083 | encountered). | |
3084 | @end table | |
3085 | ||
18fae2a8 | 3086 | Pressing @key{RET} as a means of repeating the last @value{GDBN} command is |
70b88761 RP |
3087 | disabled within a @var{command-list}. |
3088 | ||
29a2b744 | 3089 | You can use breakpoint commands to start your program up again. Simply |
70b88761 RP |
3090 | use the @code{continue} command, or @code{step}, or any other command |
3091 | that resumes execution. Subsequent commands in the command list are | |
3092 | ignored. | |
3093 | ||
3094 | @kindex silent | |
ed447b95 RP |
3095 | If the first command specified is @code{silent}, the usual message |
3096 | about stopping at a breakpoint is not printed. This may be desirable | |
3097 | for breakpoints that are to print a specific message and then continue. | |
3098 | If none of the remaining commands print anything, you will see no sign | |
3099 | that the breakpoint was reached. @code{silent} is meaningful only at | |
3100 | the beginning of a breakpoint command list. | |
70b88761 | 3101 | |
29a2b744 RP |
3102 | The commands @code{echo} and @code{output} that allow you to print |
3103 | precisely controlled output are often useful in silent breakpoints. | |
3104 | @xref{Output, ,Commands for Controlled Output}. | |
70b88761 RP |
3105 | |
3106 | For example, here is how you could use breakpoint commands to print the | |
3107 | value of @code{x} at entry to @code{foo} whenever @code{x} is positive. | |
3108 | ||
18fae2a8 | 3109 | @example |
70b88761 RP |
3110 | break foo if x>0 |
3111 | commands | |
3112 | silent | |
3113 | echo x is\040 | |
3114 | output x | |
3115 | echo \n | |
3116 | cont | |
3117 | end | |
18fae2a8 | 3118 | @end example |
70b88761 RP |
3119 | |
3120 | One application for breakpoint commands is to compensate for one bug so | |
3121 | you can test for another. Put a breakpoint just after the erroneous line | |
3122 | of code, give it a condition to detect the case in which something | |
3123 | erroneous has been done, and give it commands to assign correct values | |
3124 | to any variables that need them. End with the @code{continue} command | |
29a2b744 | 3125 | so that your program does not stop, and start with the @code{silent} |
70b88761 RP |
3126 | command so that no output is produced. Here is an example: |
3127 | ||
3128 | @example | |
3129 | break 403 | |
3130 | commands | |
3131 | silent | |
3132 | set x = y + 4 | |
3133 | cont | |
3134 | end | |
3135 | @end example | |
3136 | ||
3137 | @cindex lost output | |
3138 | One deficiency in the operation of automatically continuing breakpoints | |
3139 | under Unix appears when your program uses raw mode for the terminal. | |
18fae2a8 | 3140 | @value{GDBN} switches back to its own terminal modes (not raw) before executing |
70b88761 | 3141 | commands, and then must switch back to raw mode when your program is |
e251e767 | 3142 | continued. This causes any pending terminal input to be lost. |
70b88761 RP |
3143 | @c FIXME: revisit below when GNU sys avail. |
3144 | @c In the GNU system, this will be fixed by changing the behavior of | |
3145 | @c terminal modes. | |
3146 | ||
3147 | Under Unix, you can get around this problem by writing actions into | |
ed447b95 | 3148 | the breakpoint condition rather than in commands. For example, |
70b88761 RP |
3149 | |
3150 | @example | |
3151 | condition 5 (x = y + 4), 0 | |
3152 | @end example | |
3153 | ||
3154 | @noindent | |
1041a570 RP |
3155 | specifies a condition expression (@pxref{Expressions, ,Expressions}) that will |
3156 | change @code{x} as needed, then always have the value zero so your | |
18fae2a8 | 3157 | program will not stop. No input is lost here, because @value{GDBN} evaluates |
1041a570 RP |
3158 | break conditions without changing the terminal modes. When you want |
3159 | to have nontrivial conditions for performing the side effects, the | |
3160 | operators @samp{&&}, @samp{||} and @samp{?@dots{}:} may be useful. | |
70b88761 | 3161 | |
4eb4cf57 | 3162 | @node Breakpoint Menus |
70b88761 | 3163 | @subsection Breakpoint Menus |
b80282d5 | 3164 | @cindex overloading |
e251e767 | 3165 | @cindex symbol overloading |
70b88761 RP |
3166 | |
3167 | Some programming languages (notably C++) permit a single function name | |
3168 | to be defined several times, for application in different contexts. | |
3169 | This is called @dfn{overloading}. When a function name is overloaded, | |
18fae2a8 | 3170 | @samp{break @var{function}} is not enough to tell @value{GDBN} where you want |
6f3ec223 RP |
3171 | a breakpoint. If you realize this will be a problem, you can use |
3172 | something like @samp{break @var{function}(@var{types})} to specify which | |
18fae2a8 | 3173 | particular version of the function you want. Otherwise, @value{GDBN} offers |
6f3ec223 RP |
3174 | you a menu of numbered choices for different possible breakpoints, and |
3175 | waits for your selection with the prompt @samp{>}. The first two | |
3176 | options are always @samp{[0] cancel} and @samp{[1] all}. Typing @kbd{1} | |
3177 | sets a breakpoint at each definition of @var{function}, and typing | |
3178 | @kbd{0} aborts the @code{break} command without setting any new | |
3179 | breakpoints. | |
70b88761 RP |
3180 | |
3181 | For example, the following session excerpt shows an attempt to set a | |
e251e767 | 3182 | breakpoint at the overloaded symbol @code{String::after}. |
70b88761 RP |
3183 | We choose three particular definitions of that function name: |
3184 | ||
6f3ec223 | 3185 | @c FIXME! This is likely to change to show arg type lists, at least |
70b88761 | 3186 | @example |
18fae2a8 | 3187 | (@value{GDBP}) b String::after |
70b88761 RP |
3188 | [0] cancel |
3189 | [1] all | |
3190 | [2] file:String.cc; line number:867 | |
3191 | [3] file:String.cc; line number:860 | |
3192 | [4] file:String.cc; line number:875 | |
3193 | [5] file:String.cc; line number:853 | |
3194 | [6] file:String.cc; line number:846 | |
3195 | [7] file:String.cc; line number:735 | |
3196 | > 2 4 6 | |
3197 | Breakpoint 1 at 0xb26c: file String.cc, line 867. | |
3198 | Breakpoint 2 at 0xb344: file String.cc, line 875. | |
3199 | Breakpoint 3 at 0xafcc: file String.cc, line 846. | |
3200 | Multiple breakpoints were set. | |
3201 | Use the "delete" command to delete unwanted breakpoints. | |
18fae2a8 | 3202 | (@value{GDBP}) |
70b88761 RP |
3203 | @end example |
3204 | ||
4eb4cf57 | 3205 | @node Error in Breakpoints |
70b88761 RP |
3206 | @subsection ``Cannot Insert Breakpoints'' |
3207 | ||
e251e767 | 3208 | @c FIXME: "cannot insert breakpoints" error, v unclear. |
70b88761 | 3209 | @c Q in pending mail to Gilmore. ---pesch@cygnus.com, 26mar91 |
e251e767 | 3210 | @c some light may be shed by looking at instances of |
d24e0922 | 3211 | @c ONE_PROCESS_WRITETEXT. But error message seems possible otherwise |
c338a2fd | 3212 | @c too. pesch, 20sep91 |
70b88761 RP |
3213 | Under some operating systems, breakpoints cannot be used in a program if |
3214 | any other process is running that program. In this situation, | |
18fae2a8 | 3215 | attempting to run or continue a program with a breakpoint causes @value{GDBN} |
70b88761 RP |
3216 | to stop the other process. |
3217 | ||
3218 | When this happens, you have three ways to proceed: | |
3219 | ||
3220 | @enumerate | |
3221 | @item | |
3222 | Remove or disable the breakpoints, then continue. | |
3223 | ||
3224 | @item | |
18fae2a8 RP |
3225 | Suspend @value{GDBN}, and copy the file containing your program to a new name. |
3226 | Resume @value{GDBN} and use the @code{exec-file} command to specify that @value{GDBN} | |
29a2b744 | 3227 | should run your program under that name. Then start your program again. |
70b88761 RP |
3228 | |
3229 | @c FIXME: RMS commented here "Show example". Maybe when someone | |
3230 | @c explains the first FIXME: in this section... | |
3231 | ||
3232 | @item | |
29a2b744 | 3233 | Relink your program so that the text segment is nonsharable, using the |
70b88761 RP |
3234 | linker option @samp{-N}. The operating system limitation may not apply |
3235 | to nonsharable executables. | |
3236 | @end enumerate | |
3237 | ||
4eb4cf57 | 3238 | @node Continuing and Stepping |
3d3ab540 | 3239 | @section Continuing and Stepping |
70b88761 RP |
3240 | |
3241 | @cindex stepping | |
7463aadd RP |
3242 | @cindex continuing |
3243 | @cindex resuming execution | |
3d3ab540 | 3244 | @dfn{Continuing} means resuming program execution until your program |
cedaf8bc RP |
3245 | completes normally. In contrast, @dfn{stepping} means executing just |
3246 | one more ``step'' of your program, where ``step'' may mean either one | |
3247 | line of source code, or one machine instruction (depending on what | |
3248 | particular command you use). Either when continuing | |
4eb4cf57 | 3249 | or when stepping, your program may stop even sooner, due to |
18fae2a8 | 3250 | @ifset BARETARGET |
4eb4cf57 | 3251 | a breakpoint. |
18fae2a8 RP |
3252 | @end ifset |
3253 | @ifclear BARETARGET | |
4eb4cf57 RP |
3254 | a breakpoint or to a signal. (If due to a signal, you may want to use |
3255 | @code{handle}, or use @samp{signal 0} to resume execution. | |
3256 | @xref{Signals, ,Signals}.) | |
18fae2a8 | 3257 | @end ifclear |
3d3ab540 RP |
3258 | |
3259 | @table @code | |
3260 | @item continue @r{[}@var{ignore-count}@r{]} | |
3261 | @kindex continue | |
29a2b744 | 3262 | Resume program execution, at the address where your program last stopped; |
3d3ab540 RP |
3263 | any breakpoints set at that address are bypassed. The optional argument |
3264 | @var{ignore-count} allows you to specify a further number of times to | |
3265 | ignore a breakpoint at this location; its effect is like that of | |
29a2b744 | 3266 | @code{ignore} (@pxref{Conditions, ,Break Conditions}). |
3d3ab540 RP |
3267 | |
3268 | To resume execution at a different place, you can use @code{return} | |
29a2b744 RP |
3269 | (@pxref{Returning, ,Returning from a Function}) to go back to the |
3270 | calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a | |
1041a570 | 3271 | Different Address}) to go to an arbitrary location in your program. |
3d3ab540 | 3272 | @end table |
7463aadd RP |
3273 | |
3274 | A typical technique for using stepping is to set a breakpoint | |
29a2b744 RP |
3275 | (@pxref{Breakpoints, ,Breakpoints Watchpoints and Exceptions}) at the |
3276 | beginning of the function or the section of your program where a | |
3277 | problem is believed to lie, run your program until it stops at that | |
3278 | breakpoint, and then step through the suspect area, examining the | |
3279 | variables that are interesting, until you see the problem happen. | |
70b88761 RP |
3280 | |
3281 | @table @code | |
3282 | @item step | |
3283 | @kindex step | |
3284 | @kindex s | |
29a2b744 | 3285 | Continue running your program until control reaches a different source |
18fae2a8 | 3286 | line, then stop it and return control to @value{GDBN}. This command is |
70b88761 RP |
3287 | abbreviated @code{s}. |
3288 | ||
3d3ab540 RP |
3289 | @quotation |
3290 | @emph{Warning:} If you use the @code{step} command while control is | |
3291 | within a function that was compiled without debugging information, | |
3292 | execution will proceed until control reaches another function. | |
3293 | @end quotation | |
70b88761 RP |
3294 | |
3295 | @item step @var{count} | |
3296 | Continue running as in @code{step}, but do so @var{count} times. If a | |
3297 | breakpoint is reached or a signal not related to stepping occurs before | |
3298 | @var{count} steps, stepping stops right away. | |
3299 | ||
7463aadd | 3300 | @item next @r{[}@var{count}@r{]} |
70b88761 RP |
3301 | @kindex next |
3302 | @kindex n | |
7463aadd RP |
3303 | Continue to the next source line in the current (innermost) stack frame. |
3304 | Similar to @code{step}, but any function calls appearing within the line | |
3305 | of code are executed without stopping. Execution stops when control | |
3306 | reaches a different line of code at the stack level which was executing | |
3307 | when the @code{next} command was given. This command is abbreviated | |
3308 | @code{n}. | |
70b88761 | 3309 | |
7463aadd | 3310 | An argument @var{count} is a repeat count, as for @code{step}. |
70b88761 RP |
3311 | |
3312 | @code{next} within a function that lacks debugging information acts like | |
3313 | @code{step}, but any function calls appearing within the code of the | |
3314 | function are executed without stopping. | |
3315 | ||
3316 | @item finish | |
3317 | @kindex finish | |
7463aadd RP |
3318 | Continue running until just after function in the selected stack frame |
3319 | returns. Print the returned value (if any). | |
70b88761 | 3320 | |
29a2b744 | 3321 | Contrast this with the @code{return} command (@pxref{Returning, |
1041a570 | 3322 | ,Returning from a Function}). |
70b88761 RP |
3323 | |
3324 | @item until | |
3325 | @kindex until | |
3326 | @item u | |
3327 | @kindex u | |
3328 | Continue running until a source line past the current line, in the | |
3329 | current stack frame, is reached. This command is used to avoid single | |
3330 | stepping through a loop more than once. It is like the @code{next} | |
3331 | command, except that when @code{until} encounters a jump, it | |
3332 | automatically continues execution until the program counter is greater | |
3333 | than the address of the jump. | |
3334 | ||
3335 | This means that when you reach the end of a loop after single stepping | |
29a2b744 | 3336 | though it, @code{until} will cause your program to continue execution |
70b88761 RP |
3337 | until the loop is exited. In contrast, a @code{next} command at the end |
3338 | of a loop will simply step back to the beginning of the loop, which | |
3339 | would force you to step through the next iteration. | |
3340 | ||
29a2b744 | 3341 | @code{until} always stops your program if it attempts to exit the current |
70b88761 RP |
3342 | stack frame. |
3343 | ||
3344 | @code{until} may produce somewhat counterintuitive results if the order | |
7463aadd | 3345 | of machine code does not match the order of the source lines. For |
70b88761 RP |
3346 | example, in the following excerpt from a debugging session, the @code{f} |
3347 | (@code{frame}) command shows that execution is stopped at line | |
3348 | @code{206}; yet when we use @code{until}, we get to line @code{195}: | |
3349 | ||
3350 | @example | |
18fae2a8 | 3351 | (@value{GDBP}) f |
70b88761 | 3352 | #0 main (argc=4, argv=0xf7fffae8) at m4.c:206 |
b80282d5 | 3353 | 206 expand_input(); |
18fae2a8 | 3354 | (@value{GDBP}) until |
b80282d5 | 3355 | 195 for ( ; argc > 0; NEXTARG) @{ |
70b88761 RP |
3356 | @end example |
3357 | ||
7463aadd RP |
3358 | This happened because, for execution efficiency, the compiler had |
3359 | generated code for the loop closure test at the end, rather than the | |
3360 | start, of the loop---even though the test in a C @code{for}-loop is | |
3361 | written before the body of the loop. The @code{until} command appeared | |
3362 | to step back to the beginning of the loop when it advanced to this | |
3363 | expression; however, it has not really gone to an earlier | |
3364 | statement---not in terms of the actual machine code. | |
70b88761 RP |
3365 | |
3366 | @code{until} with no argument works by means of single | |
3367 | instruction stepping, and hence is slower than @code{until} with an | |
3368 | argument. | |
3369 | ||
3370 | @item until @var{location} | |
3371 | @item u @var{location} | |
29a2b744 RP |
3372 | Continue running your program until either the specified location is |
3373 | reached, or the current stack frame returns. @var{location} is any of | |
3374 | the forms of argument acceptable to @code{break} (@pxref{Set Breaks, | |
3375 | ,Setting Breakpoints}). This form of the command uses breakpoints, | |
1041a570 | 3376 | and hence is quicker than @code{until} without an argument. |
70b88761 RP |
3377 | |
3378 | @item stepi | |
3379 | @itemx si | |
3380 | @kindex stepi | |
3381 | @kindex si | |
3382 | Execute one machine instruction, then stop and return to the debugger. | |
3383 | ||
3384 | It is often useful to do @samp{display/i $pc} when stepping by machine | |
3385 | instructions. This will cause the next instruction to be executed to | |
29a2b744 RP |
3386 | be displayed automatically at each stop. @xref{Auto Display, |
3387 | ,Automatic Display}. | |
70b88761 RP |
3388 | |
3389 | An argument is a repeat count, as in @code{step}. | |
3390 | ||
ed447b95 | 3391 | @need 750 |
70b88761 RP |
3392 | @item nexti |
3393 | @itemx ni | |
3394 | @kindex nexti | |
3395 | @kindex ni | |
3396 | Execute one machine instruction, but if it is a function call, | |
3397 | proceed until the function returns. | |
3398 | ||
3399 | An argument is a repeat count, as in @code{next}. | |
70b88761 RP |
3400 | @end table |
3401 | ||
18fae2a8 | 3402 | @ifset POSIX |
4eb4cf57 | 3403 | @node Signals |
70b88761 RP |
3404 | @section Signals |
3405 | @cindex signals | |
3406 | ||
3407 | A signal is an asynchronous event that can happen in a program. The | |
3408 | operating system defines the possible kinds of signals, and gives each | |
3409 | kind a name and a number. For example, in Unix @code{SIGINT} is the | |
3410 | signal a program gets when you type an interrupt (often @kbd{C-c}); | |
3411 | @code{SIGSEGV} is the signal a program gets from referencing a place in | |
3412 | memory far away from all the areas in use; @code{SIGALRM} occurs when | |
29a2b744 | 3413 | the alarm clock timer goes off (which happens only if your program has |
70b88761 RP |
3414 | requested an alarm). |
3415 | ||
3416 | @cindex fatal signals | |
3417 | Some signals, including @code{SIGALRM}, are a normal part of the | |
29a2b744 RP |
3418 | functioning of your program. Others, such as @code{SIGSEGV}, indicate |
3419 | errors; these signals are @dfn{fatal} (kill your program immediately) if the | |
70b88761 | 3420 | program has not specified in advance some other way to handle the signal. |
29a2b744 | 3421 | @code{SIGINT} does not indicate an error in your program, but it is normally |
70b88761 RP |
3422 | fatal so it can carry out the purpose of the interrupt: to kill the program. |
3423 | ||
18fae2a8 RP |
3424 | @value{GDBN} has the ability to detect any occurrence of a signal in your |
3425 | program. You can tell @value{GDBN} in advance what to do for each kind of | |
29a2b744 | 3426 | signal. |
70b88761 RP |
3427 | |
3428 | @cindex handling signals | |
18fae2a8 | 3429 | Normally, @value{GDBN} is set up to ignore non-erroneous signals like @code{SIGALRM} |
29a2b744 RP |
3430 | (so as not to interfere with their role in the functioning of your program) |
3431 | but to stop your program immediately whenever an error signal happens. | |
70b88761 RP |
3432 | You can change these settings with the @code{handle} command. |
3433 | ||
3434 | @table @code | |
3435 | @item info signals | |
3436 | @kindex info signals | |
18fae2a8 | 3437 | Print a table of all the kinds of signals and how @value{GDBN} has been told to |
70b88761 RP |
3438 | handle each one. You can use this to see the signal numbers of all |
3439 | the defined types of signals. | |
3440 | ||
3441 | @item handle @var{signal} @var{keywords}@dots{} | |
3442 | @kindex handle | |
18fae2a8 | 3443 | Change the way @value{GDBN} handles signal @var{signal}. @var{signal} can be the |
70b88761 RP |
3444 | number of a signal or its name (with or without the @samp{SIG} at the |
3445 | beginning). The @var{keywords} say what change to make. | |
3446 | @end table | |
3447 | ||
3448 | @c @group | |
3449 | The keywords allowed by the @code{handle} command can be abbreviated. | |
3450 | Their full names are: | |
3451 | ||
3452 | @table @code | |
3453 | @item nostop | |
18fae2a8 | 3454 | @value{GDBN} should not stop your program when this signal happens. It may |
70b88761 RP |
3455 | still print a message telling you that the signal has come in. |
3456 | ||
3457 | @item stop | |
18fae2a8 | 3458 | @value{GDBN} should stop your program when this signal happens. This implies |
70b88761 RP |
3459 | the @code{print} keyword as well. |
3460 | ||
3461 | @item print | |
18fae2a8 | 3462 | @value{GDBN} should print a message when this signal happens. |
70b88761 RP |
3463 | |
3464 | @item noprint | |
18fae2a8 | 3465 | @value{GDBN} should not mention the occurrence of the signal at all. This |
70b88761 RP |
3466 | implies the @code{nostop} keyword as well. |
3467 | ||
3468 | @item pass | |
18fae2a8 | 3469 | @value{GDBN} should allow your program to see this signal; your program will be |
70b88761 RP |
3470 | able to handle the signal, or may be terminated if the signal is fatal |
3471 | and not handled. | |
3472 | ||
3473 | @item nopass | |
18fae2a8 | 3474 | @value{GDBN} should not allow your program to see this signal. |
70b88761 RP |
3475 | @end table |
3476 | @c @end group | |
3477 | ||
ed447b95 RP |
3478 | When a signal stops your program, the signal is not visible until you |
3479 | continue. Your program will see the signal then, if @code{pass} is in | |
3480 | effect for the signal in question @emph{at that time}. In other words, | |
3481 | after @value{GDBN} reports a signal, you can use the @code{handle} | |
3482 | command with @code{pass} or @code{nopass} to control whether that | |
3483 | signal will be seen by your program when you later continue it. | |
70b88761 | 3484 | |
29a2b744 | 3485 | You can also use the @code{signal} command to prevent your program from |
70b88761 | 3486 | seeing a signal, or cause it to see a signal it normally would not see, |
29a2b744 | 3487 | or to give it any signal at any time. For example, if your program stopped |
7463aadd RP |
3488 | due to some sort of memory reference error, you might store correct |
3489 | values into the erroneous variables and continue, hoping to see more | |
29a2b744 RP |
3490 | execution; but your program would probably terminate immediately as |
3491 | a result of the fatal signal once it saw the signal. To prevent this, | |
3492 | you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your | |
3493 | Program a Signal}. | |
18fae2a8 | 3494 | @end ifset |
70b88761 | 3495 | |
4eb4cf57 | 3496 | @node Stack |
70b88761 RP |
3497 | @chapter Examining the Stack |
3498 | ||
3499 | When your program has stopped, the first thing you need to know is where it | |
3500 | stopped and how it got there. | |
3501 | ||
3502 | @cindex call stack | |
3503 | Each time your program performs a function call, the information about | |
29a2b744 | 3504 | where in your program the call was made from is saved in a block of data |
70b88761 RP |
3505 | called a @dfn{stack frame}. The frame also contains the arguments of the |
3506 | call and the local variables of the function that was called. All the | |
3507 | stack frames are allocated in a region of memory called the @dfn{call | |
3508 | stack}. | |
3509 | ||
18fae2a8 | 3510 | When your program stops, the @value{GDBN} commands for examining the stack allow you |
70b88761 RP |
3511 | to see all of this information. |
3512 | ||
3513 | @cindex selected frame | |
18fae2a8 | 3514 | One of the stack frames is @dfn{selected} by @value{GDBN} and many @value{GDBN} commands |
70b88761 | 3515 | refer implicitly to the selected frame. In particular, whenever you ask |
18fae2a8 RP |
3516 | @value{GDBN} for the value of a variable in your program, the value is found in the |
3517 | selected frame. There are special @value{GDBN} commands to select whichever frame | |
70b88761 RP |
3518 | you are interested in. |
3519 | ||
18fae2a8 | 3520 | When your program stops, @value{GDBN} automatically selects the currently executing |
70b88761 | 3521 | frame and describes it briefly as the @code{frame} command does |
29a2b744 | 3522 | (@pxref{Frame Info, ,Information About a Frame}). |
70b88761 RP |
3523 | |
3524 | @menu | |
ed447b95 | 3525 | * Frames:: Stack frames |
b80282d5 | 3526 | * Backtrace:: Backtraces |
ed447b95 RP |
3527 | * Selection:: Selecting a frame |
3528 | * Frame Info:: Information on a frame | |
70b88761 RP |
3529 | @end menu |
3530 | ||
4eb4cf57 | 3531 | @node Frames |
70b88761 RP |
3532 | @section Stack Frames |
3533 | ||
3534 | @cindex frame | |
3535 | @cindex stack frame | |
3536 | The call stack is divided up into contiguous pieces called @dfn{stack | |
3537 | frames}, or @dfn{frames} for short; each frame is the data associated | |
3538 | with one call to one function. The frame contains the arguments given | |
3539 | to the function, the function's local variables, and the address at | |
3540 | which the function is executing. | |
3541 | ||
3542 | @cindex initial frame | |
3543 | @cindex outermost frame | |
3544 | @cindex innermost frame | |
3545 | When your program is started, the stack has only one frame, that of the | |
3546 | function @code{main}. This is called the @dfn{initial} frame or the | |
3547 | @dfn{outermost} frame. Each time a function is called, a new frame is | |
3548 | made. Each time a function returns, the frame for that function invocation | |
3549 | is eliminated. If a function is recursive, there can be many frames for | |
3550 | the same function. The frame for the function in which execution is | |
3551 | actually occurring is called the @dfn{innermost} frame. This is the most | |
3552 | recently created of all the stack frames that still exist. | |
3553 | ||
3554 | @cindex frame pointer | |
3555 | Inside your program, stack frames are identified by their addresses. A | |
3556 | stack frame consists of many bytes, each of which has its own address; each | |
3557 | kind of computer has a convention for choosing one of those bytes whose | |
3558 | address serves as the address of the frame. Usually this address is kept | |
3559 | in a register called the @dfn{frame pointer register} while execution is | |
3560 | going on in that frame. | |
3561 | ||
3562 | @cindex frame number | |
18fae2a8 | 3563 | @value{GDBN} assigns numbers to all existing stack frames, starting with |
70b88761 RP |
3564 | zero for the innermost frame, one for the frame that called it, |
3565 | and so on upward. These numbers do not really exist in your program; | |
18fae2a8 RP |
3566 | they are assigned by @value{GDBN} to give you a way of designating stack |
3567 | frames in @value{GDBN} commands. | |
70b88761 RP |
3568 | |
3569 | @cindex frameless execution | |
3570 | Some compilers allow functions to be compiled so that they operate | |
18fae2a8 | 3571 | without stack frames. (For example, the @code{@value{GCC}} option |
70b88761 RP |
3572 | @samp{-fomit-frame-pointer} will generate functions without a frame.) |
3573 | This is occasionally done with heavily used library functions to save | |
18fae2a8 | 3574 | the frame setup time. @value{GDBN} has limited facilities for dealing with |
70b88761 | 3575 | these function invocations. If the innermost function invocation has no |
18fae2a8 | 3576 | stack frame, @value{GDBN} will nevertheless regard it as though it had a |
70b88761 | 3577 | separate frame, which is numbered zero as usual, allowing correct |
18fae2a8 | 3578 | tracing of the function call chain. However, @value{GDBN} has no provision |
70b88761 RP |
3579 | for frameless functions elsewhere in the stack. |
3580 | ||
4eb4cf57 | 3581 | @node Backtrace |
70b88761 RP |
3582 | @section Backtraces |
3583 | ||
29a2b744 | 3584 | A backtrace is a summary of how your program got where it is. It shows one |
70b88761 RP |
3585 | line per frame, for many frames, starting with the currently executing |
3586 | frame (frame zero), followed by its caller (frame one), and on up the | |
3587 | stack. | |
3588 | ||
3589 | @table @code | |
3590 | @item backtrace | |
3591 | @itemx bt | |
3592 | @kindex backtrace | |
3593 | @kindex bt | |
3594 | Print a backtrace of the entire stack: one line per frame for all | |
3595 | frames in the stack. | |
3596 | ||
3597 | You can stop the backtrace at any time by typing the system interrupt | |
3598 | character, normally @kbd{C-c}. | |
3599 | ||
3600 | @item backtrace @var{n} | |
3601 | @itemx bt @var{n} | |
3602 | Similar, but print only the innermost @var{n} frames. | |
3603 | ||
3604 | @item backtrace -@var{n} | |
3605 | @itemx bt -@var{n} | |
3606 | Similar, but print only the outermost @var{n} frames. | |
3607 | @end table | |
3608 | ||
3609 | @kindex where | |
3610 | @kindex info stack | |
3611 | @kindex info s | |
3612 | The names @code{where} and @code{info stack} (abbreviated @code{info s}) | |
3613 | are additional aliases for @code{backtrace}. | |
3614 | ||
3615 | Each line in the backtrace shows the frame number and the function name. | |
3616 | The program counter value is also shown---unless you use @code{set | |
3617 | print address off}. The backtrace also shows the source file name and | |
3618 | line number, as well as the arguments to the function. The program | |
3619 | counter value is omitted if it is at the beginning of the code for that | |
3620 | line number. | |
3621 | ||
3622 | Here is an example of a backtrace. It was made with the command | |
3623 | @samp{bt 3}, so it shows the innermost three frames. | |
3624 | ||
3625 | @smallexample | |
3626 | @group | |
203eea5d RP |
3627 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) |
3628 | at builtin.c:993 | |
70b88761 RP |
3629 | #1 0x6e38 in expand_macro (sym=0x2b600) at macro.c:242 |
3630 | #2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08) | |
3631 | at macro.c:71 | |
3632 | (More stack frames follow...) | |
3633 | @end group | |
3634 | @end smallexample | |
3635 | ||
3636 | @noindent | |
29a2b744 RP |
3637 | The display for frame zero does not begin with a program counter |
3638 | value, indicating that your program has stopped at the beginning of the | |
70b88761 RP |
3639 | code for line @code{993} of @code{builtin.c}. |
3640 | ||
4eb4cf57 | 3641 | @node Selection |
70b88761 RP |
3642 | @section Selecting a Frame |
3643 | ||
29a2b744 | 3644 | Most commands for examining the stack and other data in your program work on |
70b88761 RP |
3645 | whichever stack frame is selected at the moment. Here are the commands for |
3646 | selecting a stack frame; all of them finish by printing a brief description | |
3647 | of the stack frame just selected. | |
3648 | ||
3649 | @table @code | |
3650 | @item frame @var{n} | |
3651 | @itemx f @var{n} | |
3652 | @kindex frame | |
3653 | @kindex f | |
3654 | Select frame number @var{n}. Recall that frame zero is the innermost | |
3655 | (currently executing) frame, frame one is the frame that called the | |
3656 | innermost one, and so on. The highest-numbered frame is @code{main}'s | |
3657 | frame. | |
3658 | ||
3659 | @item frame @var{addr} | |
3660 | @itemx f @var{addr} | |
3661 | Select the frame at address @var{addr}. This is useful mainly if the | |
3662 | chaining of stack frames has been damaged by a bug, making it | |
18fae2a8 | 3663 | impossible for @value{GDBN} to assign numbers properly to all frames. In |
29a2b744 | 3664 | addition, this can be useful when your program has multiple stacks and |
70b88761 RP |
3665 | switches between them. |
3666 | ||
18fae2a8 | 3667 | @ifset SPARC |
70b88761 | 3668 | On the SPARC architecture, @code{frame} needs two addresses to |
e251e767 | 3669 | select an arbitrary frame: a frame pointer and a stack pointer. |
70b88761 RP |
3670 | @c note to future updaters: this is conditioned on a flag |
3671 | @c FRAME_SPECIFICATION_DYADIC in the tm-*.h files, currently only used | |
3672 | @c by SPARC, hence the specific attribution. Generalize or list all | |
3673 | @c possibilities if more supported machines start doing this. | |
18fae2a8 | 3674 | @end ifset |
70b88761 RP |
3675 | |
3676 | @item up @var{n} | |
3677 | @kindex up | |
3678 | Move @var{n} frames up the stack. For positive numbers @var{n}, this | |
3679 | advances toward the outermost frame, to higher frame numbers, to frames | |
3680 | that have existed longer. @var{n} defaults to one. | |
3681 | ||
3682 | @item down @var{n} | |
3683 | @kindex down | |
3684 | @kindex do | |
3685 | Move @var{n} frames down the stack. For positive numbers @var{n}, this | |
3686 | advances toward the innermost frame, to lower frame numbers, to frames | |
3687 | that were created more recently. @var{n} defaults to one. You may | |
3688 | abbreviate @code{down} as @code{do}. | |
3689 | @end table | |
3690 | ||
3691 | All of these commands end by printing two lines of output describing the | |
3692 | frame. The first line shows the frame number, the function name, the | |
3693 | arguments, and the source file and line number of execution in that | |
ed447b95 | 3694 | frame. The second line shows the text of that source line. |
70b88761 | 3695 | |
ed447b95 | 3696 | For example: |
70b88761 | 3697 | @smallexample |
29a2b744 | 3698 | @group |
18fae2a8 | 3699 | (@value{GDBP}) up |
203eea5d RP |
3700 | #1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc) |
3701 | at env.c:10 | |
70b88761 | 3702 | 10 read_input_file (argv[i]); |
29a2b744 | 3703 | @end group |
70b88761 RP |
3704 | @end smallexample |
3705 | ||
29a2b744 RP |
3706 | After such a printout, the @code{list} command with no arguments will |
3707 | print ten lines centered on the point of execution in the frame. | |
3708 | @xref{List, ,Printing Source Lines}. | |
70b88761 RP |
3709 | |
3710 | @table @code | |
3711 | @item up-silently @var{n} | |
3712 | @itemx down-silently @var{n} | |
3713 | @kindex down-silently | |
3714 | @kindex up-silently | |
3715 | These two commands are variants of @code{up} and @code{down}, | |
3716 | respectively; they differ in that they do their work silently, without | |
3717 | causing display of the new frame. They are intended primarily for use | |
18fae2a8 | 3718 | in @value{GDBN} command scripts, where the output might be unnecessary and |
e251e767 | 3719 | distracting. |
70b88761 RP |
3720 | @end table |
3721 | ||
4eb4cf57 | 3722 | @node Frame Info |
70b88761 RP |
3723 | @section Information About a Frame |
3724 | ||
3725 | There are several other commands to print information about the selected | |
3726 | stack frame. | |
3727 | ||
3728 | @table @code | |
3729 | @item frame | |
3730 | @itemx f | |
29a2b744 RP |
3731 | When used without any argument, this command does not change which |
3732 | frame is selected, but prints a brief description of the currently | |
70b88761 | 3733 | selected stack frame. It can be abbreviated @code{f}. With an |
ed447b95 RP |
3734 | argument, this command is used to select a stack frame. |
3735 | @xref{Selection, ,Selecting a Frame}. | |
70b88761 RP |
3736 | |
3737 | @item info frame | |
70b88761 | 3738 | @itemx info f |
29a2b744 | 3739 | @kindex info frame |
70b88761 RP |
3740 | @kindex info f |
3741 | This command prints a verbose description of the selected stack frame, | |
3742 | including the address of the frame, the addresses of the next frame down | |
c2bbbb22 RP |
3743 | (called by this frame) and the next frame up (caller of this frame), the |
3744 | language that the source code corresponding to this frame was written in, | |
70b88761 RP |
3745 | the address of the frame's arguments, the program counter saved in it |
3746 | (the address of execution in the caller frame), and which registers | |
3747 | were saved in the frame. The verbose description is useful when | |
3748 | something has gone wrong that has made the stack format fail to fit | |
3749 | the usual conventions. | |
3750 | ||
3751 | @item info frame @var{addr} | |
3752 | @itemx info f @var{addr} | |
3753 | Print a verbose description of the frame at address @var{addr}, | |
3754 | without selecting that frame. The selected frame remains unchanged by | |
3755 | this command. | |
3756 | ||
3757 | @item info args | |
3758 | @kindex info args | |
3759 | Print the arguments of the selected frame, each on a separate line. | |
3760 | ||
3761 | @item info locals | |
3762 | @kindex info locals | |
3763 | Print the local variables of the selected frame, each on a separate | |
ed447b95 RP |
3764 | line. These are all variables (declared either static or automatic) |
3765 | accessible at the point of execution of the selected frame. | |
70b88761 RP |
3766 | |
3767 | @item info catch | |
3768 | @kindex info catch | |
3769 | @cindex catch exceptions | |
3770 | @cindex exception handlers | |
3771 | Print a list of all the exception handlers that are active in the | |
3772 | current stack frame at the current point of execution. To see other | |
3773 | exception handlers, visit the associated frame (using the @code{up}, | |
3774 | @code{down}, or @code{frame} commands); then type @code{info catch}. | |
1041a570 | 3775 | @xref{Exception Handling, ,Breakpoints and Exceptions}. |
70b88761 RP |
3776 | @end table |
3777 | ||
4eb4cf57 | 3778 | @node Source |
70b88761 RP |
3779 | @chapter Examining Source Files |
3780 | ||
18fae2a8 | 3781 | @value{GDBN} can print parts of your program's source, since the debugging |
ed447b95 | 3782 | information recorded in the program tells @value{GDBN} what source files were |
18fae2a8 | 3783 | used to build it. When your program stops, @value{GDBN} spontaneously prints |
1041a570 | 3784 | the line where it stopped. Likewise, when you select a stack frame |
18fae2a8 | 3785 | (@pxref{Selection, ,Selecting a Frame}), @value{GDBN} prints the line where |
1041a570 RP |
3786 | execution in that frame has stopped. You can print other portions of |
3787 | source files by explicit command. | |
70b88761 | 3788 | |
18fae2a8 RP |
3789 | @ifclear DOSHOST |
3790 | If you use @value{GDBN} through its GNU Emacs interface, you may prefer to use | |
3791 | Emacs facilities to view source; @pxref{Emacs, ,Using @value{GDBN} under GNU | |
1041a570 | 3792 | Emacs}. |
18fae2a8 | 3793 | @end ifclear |
70b88761 | 3794 | |
18fae2a8 RP |
3795 | @ignore |
3796 | @c pre-unfolded menu | |
70b88761 | 3797 | @menu |
ed447b95 | 3798 | * List:: Printing source lines |
18fae2a8 | 3799 | @ifclear DOSHOST |
ed447b95 | 3800 | * Search:: Searching source files |
18fae2a8 | 3801 | @end ifclear |
ed447b95 RP |
3802 | * Source Path:: Specifying source directories |
3803 | * Machine Code:: Source and machine code | |
70b88761 | 3804 | @end menu |
18fae2a8 RP |
3805 | @end ignore |
3806 | ||
3807 | @ifclear DOSHOST | |
3808 | @menu | |
ed447b95 RP |
3809 | * List:: Printing source lines |
3810 | * Search:: Searching source files | |
3811 | * Source Path:: Specifying source directories | |
3812 | * Machine Code:: Source and machine code | |
18fae2a8 RP |
3813 | @end menu |
3814 | @end ifclear | |
3815 | ||
3816 | @ifset DOSHOST | |
3817 | @menu | |
ed447b95 RP |
3818 | * List:: Printing source lines |
3819 | * Source Path:: Specifying source directories | |
3820 | * Machine Code:: Source and machine code | |
18fae2a8 RP |
3821 | @end menu |
3822 | @end ifset | |
70b88761 | 3823 | |
4eb4cf57 | 3824 | @node List |
70b88761 RP |
3825 | @section Printing Source Lines |
3826 | ||
3827 | @kindex list | |
3828 | @kindex l | |
3829 | To print lines from a source file, use the @code{list} command | |
3830 | (abbreviated @code{l}). There are several ways to specify what part | |
3831 | of the file you want to print. | |
3832 | ||
3833 | Here are the forms of the @code{list} command most commonly used: | |
3834 | ||
3835 | @table @code | |
3836 | @item list @var{linenum} | |
c338a2fd | 3837 | Print lines centered around line number @var{linenum} in the |
70b88761 RP |
3838 | current source file. |
3839 | ||
3840 | @item list @var{function} | |
c338a2fd | 3841 | Print lines centered around the beginning of function |
70b88761 RP |
3842 | @var{function}. |
3843 | ||
3844 | @item list | |
c338a2fd RP |
3845 | Print more lines. If the last lines printed were printed with a |
3846 | @code{list} command, this prints lines following the last lines | |
70b88761 | 3847 | printed; however, if the last line printed was a solitary line printed |
29a2b744 | 3848 | as part of displaying a stack frame (@pxref{Stack, ,Examining the |
1041a570 | 3849 | Stack}), this prints lines centered around that line. |
70b88761 RP |
3850 | |
3851 | @item list - | |
c338a2fd RP |
3852 | Print lines just before the lines last printed. |
3853 | @end table | |
3854 | ||
18fae2a8 | 3855 | By default, @value{GDBN} prints ten source lines with any of these forms of |
c338a2fd RP |
3856 | the @code{list} command. You can change this using @code{set listsize}: |
3857 | ||
3858 | @table @code | |
3859 | @item set listsize @var{count} | |
3860 | @kindex set listsize | |
3861 | Make the @code{list} command display @var{count} source lines (unless | |
3862 | the @code{list} argument explicitly specifies some other number). | |
3863 | ||
3864 | @item show listsize | |
3865 | @kindex show listsize | |
3866 | Display the number of lines that @code{list} will currently display by | |
e251e767 | 3867 | default. |
70b88761 RP |
3868 | @end table |
3869 | ||
3870 | Repeating a @code{list} command with @key{RET} discards the argument, | |
3871 | so it is equivalent to typing just @code{list}. This is more useful | |
3872 | than listing the same lines again. An exception is made for an | |
3873 | argument of @samp{-}; that argument is preserved in repetition so that | |
3874 | each repetition moves up in the source file. | |
3875 | ||
3876 | @cindex linespec | |
3877 | In general, the @code{list} command expects you to supply zero, one or two | |
3878 | @dfn{linespecs}. Linespecs specify source lines; there are several ways | |
3879 | of writing them but the effect is always to specify some source line. | |
3880 | Here is a complete description of the possible arguments for @code{list}: | |
3881 | ||
3882 | @table @code | |
3883 | @item list @var{linespec} | |
c338a2fd | 3884 | Print lines centered around the line specified by @var{linespec}. |
70b88761 RP |
3885 | |
3886 | @item list @var{first},@var{last} | |
3887 | Print lines from @var{first} to @var{last}. Both arguments are | |
3888 | linespecs. | |
3889 | ||
3890 | @item list ,@var{last} | |
c338a2fd | 3891 | Print lines ending with @var{last}. |
70b88761 RP |
3892 | |
3893 | @item list @var{first}, | |
c338a2fd | 3894 | Print lines starting with @var{first}. |
70b88761 RP |
3895 | |
3896 | @item list + | |
c338a2fd | 3897 | Print lines just after the lines last printed. |
70b88761 RP |
3898 | |
3899 | @item list - | |
c338a2fd | 3900 | Print lines just before the lines last printed. |
70b88761 RP |
3901 | |
3902 | @item list | |
3903 | As described in the preceding table. | |
3904 | @end table | |
3905 | ||
3906 | Here are the ways of specifying a single source line---all the | |
3907 | kinds of linespec. | |
3908 | ||
3909 | @table @code | |
3910 | @item @var{number} | |
3911 | Specifies line @var{number} of the current source file. | |
3912 | When a @code{list} command has two linespecs, this refers to | |
3913 | the same source file as the first linespec. | |
3914 | ||
3915 | @item +@var{offset} | |
3916 | Specifies the line @var{offset} lines after the last line printed. | |
3917 | When used as the second linespec in a @code{list} command that has | |
3918 | two, this specifies the line @var{offset} lines down from the | |
3919 | first linespec. | |
3920 | ||
3921 | @item -@var{offset} | |
3922 | Specifies the line @var{offset} lines before the last line printed. | |
3923 | ||
3924 | @item @var{filename}:@var{number} | |
3925 | Specifies line @var{number} in the source file @var{filename}. | |
3926 | ||
3927 | @item @var{function} | |
3928 | @c FIXME: "of the open-brace" is C-centric. When we add other langs... | |
3929 | Specifies the line of the open-brace that begins the body of the | |
3930 | function @var{function}. | |
3931 | ||
3932 | @item @var{filename}:@var{function} | |
3933 | Specifies the line of the open-brace that begins the body of the | |
3934 | function @var{function} in the file @var{filename}. You only need the | |
3935 | file name with a function name to avoid ambiguity when there are | |
3936 | identically named functions in different source files. | |
3937 | ||
3938 | @item *@var{address} | |
3939 | Specifies the line containing the program address @var{address}. | |
3940 | @var{address} may be any expression. | |
3941 | @end table | |
3942 | ||
18fae2a8 | 3943 | @ifclear DOSHOST |
4eb4cf57 | 3944 | @node Search |
70b88761 RP |
3945 | @section Searching Source Files |
3946 | @cindex searching | |
3947 | @kindex reverse-search | |
3948 | ||
3949 | There are two commands for searching through the current source file for a | |
3950 | regular expression. | |
3951 | ||
3952 | @table @code | |
3953 | @item forward-search @var{regexp} | |
3954 | @itemx search @var{regexp} | |
3955 | @kindex search | |
3956 | @kindex forward-search | |
1041a570 RP |
3957 | The command @samp{forward-search @var{regexp}} checks each line, |
3958 | starting with the one following the last line listed, for a match for | |
3959 | @var{regexp}. It lists the line that is found. You can use | |
3960 | synonym @samp{search @var{regexp}} or abbreviate the command name as | |
3961 | @code{fo}. | |
70b88761 RP |
3962 | |
3963 | @item reverse-search @var{regexp} | |
3964 | The command @samp{reverse-search @var{regexp}} checks each line, starting | |
3965 | with the one before the last line listed and going backward, for a match | |
3966 | for @var{regexp}. It lists the line that is found. You can abbreviate | |
3967 | this command as @code{rev}. | |
3968 | @end table | |
18fae2a8 | 3969 | @end ifclear |
70b88761 | 3970 | |
4eb4cf57 | 3971 | @node Source Path |
70b88761 RP |
3972 | @section Specifying Source Directories |
3973 | ||
3974 | @cindex source path | |
3975 | @cindex directories for source files | |
3976 | Executable programs sometimes do not record the directories of the source | |
3977 | files from which they were compiled, just the names. Even when they do, | |
3978 | the directories could be moved between the compilation and your debugging | |
18fae2a8 RP |
3979 | session. @value{GDBN} has a list of directories to search for source files; |
3980 | this is called the @dfn{source path}. Each time @value{GDBN} wants a source file, | |
70b88761 RP |
3981 | it tries all the directories in the list, in the order they are present |
3982 | in the list, until it finds a file with the desired name. Note that | |
3983 | the executable search path is @emph{not} used for this purpose. Neither is | |
3984 | the current working directory, unless it happens to be in the source | |
3985 | path. | |
3986 | ||
18fae2a8 RP |
3987 | If @value{GDBN} cannot find a source file in the source path, and the object |
3988 | program records a directory, @value{GDBN} tries that directory too. If the | |
70b88761 | 3989 | source path is empty, and there is no record of the compilation |
18fae2a8 | 3990 | directory, @value{GDBN} will, as a last resort, look in the current |
70b88761 RP |
3991 | directory. |
3992 | ||
18fae2a8 | 3993 | Whenever you reset or rearrange the source path, @value{GDBN} will clear out |
70b88761 RP |
3994 | any information it has cached about where source files are found, where |
3995 | each line is in the file, etc. | |
3996 | ||
3997 | @kindex directory | |
18fae2a8 | 3998 | When you start @value{GDBN}, its source path is empty. |
70b88761 RP |
3999 | To add other directories, use the @code{directory} command. |
4000 | ||
4001 | @table @code | |
4002 | @item directory @var{dirname} @dots{} | |
4003 | Add directory @var{dirname} to the front of the source path. Several | |
4004 | directory names may be given to this command, separated by @samp{:} or | |
4005 | whitespace. You may specify a directory that is already in the source | |
e251e767 | 4006 | path; this moves it forward, so it will be searched sooner. |
7463aadd RP |
4007 | |
4008 | You can use the string @samp{$cdir} to refer to the compilation | |
4009 | directory (if one is recorded), and @samp{$cwd} to refer to the current | |
4010 | working directory. @samp{$cwd} is not the same as @samp{.}---the former | |
18fae2a8 | 4011 | tracks the current working directory as it changes during your @value{GDBN} |
7463aadd RP |
4012 | session, while the latter is immediately expanded to the current |
4013 | directory at the time you add an entry to the source path. | |
70b88761 RP |
4014 | |
4015 | @item directory | |
4016 | Reset the source path to empty again. This requires confirmation. | |
4017 | ||
4018 | @c RET-repeat for @code{directory} is explicitly disabled, but since | |
29a2b744 | 4019 | @c repeating it would be a no-op we do not say that. (thanks to RMS) |
70b88761 RP |
4020 | |
4021 | @item show directories | |
4022 | @kindex show directories | |
4023 | Print the source path: show which directories it contains. | |
4024 | @end table | |
4025 | ||
4026 | If your source path is cluttered with directories that are no longer of | |
18fae2a8 | 4027 | interest, @value{GDBN} may sometimes cause confusion by finding the wrong |
70b88761 RP |
4028 | versions of source. You can correct the situation as follows: |
4029 | ||
4030 | @enumerate | |
4031 | @item | |
4032 | Use @code{directory} with no argument to reset the source path to empty. | |
4033 | ||
4034 | @item | |
4035 | Use @code{directory} with suitable arguments to reinstall the | |
4036 | directories you want in the source path. You can add all the | |
4037 | directories in one command. | |
4038 | @end enumerate | |
4039 | ||
4eb4cf57 | 4040 | @node Machine Code |
70b88761 | 4041 | @section Source and Machine Code |
1041a570 | 4042 | |
70b88761 | 4043 | You can use the command @code{info line} to map source lines to program |
ed447b95 | 4044 | addresses (and vice versa), and the command @code{disassemble} to display |
70b88761 RP |
4045 | a range of addresses as machine instructions. |
4046 | ||
4047 | @table @code | |
4048 | @item info line @var{linespec} | |
4049 | @kindex info line | |
4050 | Print the starting and ending addresses of the compiled code for | |
1041a570 RP |
4051 | source line @var{linespec}. You can specify source lines in any of |
4052 | the ways understood by the @code{list} command (@pxref{List, ,Printing | |
4053 | Source Lines}). | |
70b88761 RP |
4054 | @end table |
4055 | ||
1041a570 RP |
4056 | For example, we can use @code{info line} to discover the location of |
4057 | the object code for the first line of function | |
4058 | @code{m4_changequote}: | |
4059 | ||
70b88761 | 4060 | @smallexample |
18fae2a8 | 4061 | (@value{GDBP}) info line m4_changecom |
70b88761 RP |
4062 | Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350. |
4063 | @end smallexample | |
4064 | ||
4065 | @noindent | |
4066 | We can also inquire (using @code{*@var{addr}} as the form for | |
4067 | @var{linespec}) what source line covers a particular address: | |
4068 | @smallexample | |
18fae2a8 | 4069 | (@value{GDBP}) info line *0x63ff |
70b88761 RP |
4070 | Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404. |
4071 | @end smallexample | |
4072 | ||
c338a2fd | 4073 | @cindex @code{$_} and @code{info line} |
29a2b744 RP |
4074 | After @code{info line}, the default address for the @code{x} command |
4075 | is changed to the starting address of the line, so that @samp{x/i} is | |
4076 | sufficient to begin examining the machine code (@pxref{Memory, | |
4077 | ,Examining Memory}). Also, this address is saved as the value of the | |
4078 | convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience | |
4079 | Variables}). | |
70b88761 RP |
4080 | |
4081 | @table @code | |
4082 | @kindex disassemble | |
4083 | @item disassemble | |
e94b4a2b RP |
4084 | This specialized command dumps a range of memory as machine |
4085 | instructions. The default memory range is the function surrounding the | |
4086 | program counter of the selected frame. A single argument to this | |
4087 | command is a program counter value; the function surrounding this value | |
4088 | will be dumped. Two arguments specify a range of addresses (first | |
4089 | inclusive, second exclusive) to dump. | |
70b88761 RP |
4090 | @end table |
4091 | ||
18fae2a8 | 4092 | @ifclear HviiiEXCLUSIVE |
70b88761 | 4093 | We can use @code{disassemble} to inspect the object code |
4eb4cf57 RP |
4094 | range shown in the last @code{info line} example (the example |
4095 | shows SPARC machine instructions): | |
70b88761 | 4096 | |
18fae2a8 | 4097 | |
70b88761 | 4098 | @smallexample |
18fae2a8 | 4099 | (@value{GDBP}) disas 0x63e4 0x6404 |
70b88761 | 4100 | Dump of assembler code from 0x63e4 to 0x6404: |
b80282d5 RP |
4101 | 0x63e4 <builtin_init+5340>: ble 0x63f8 <builtin_init+5360> |
4102 | 0x63e8 <builtin_init+5344>: sethi %hi(0x4c00), %o0 | |
4103 | 0x63ec <builtin_init+5348>: ld [%i1+4], %o0 | |
4104 | 0x63f0 <builtin_init+5352>: b 0x63fc <builtin_init+5364> | |
4105 | 0x63f4 <builtin_init+5356>: ld [%o0+4], %o0 | |
4106 | 0x63f8 <builtin_init+5360>: or %o0, 0x1a4, %o0 | |
4107 | 0x63fc <builtin_init+5364>: call 0x9288 <path_search> | |
e251e767 | 4108 | 0x6400 <builtin_init+5368>: nop |
70b88761 | 4109 | End of assembler dump. |
70b88761 | 4110 | @end smallexample |
18fae2a8 | 4111 | @end ifclear |
4eb4cf57 | 4112 | |
18fae2a8 | 4113 | @ifset HviiiEXCLUSIVE |
4eb4cf57 RP |
4114 | For example, here is the beginning of the output for the |
4115 | disassembly of a function @code{fact}: | |
70b88761 | 4116 | |
18fae2a8 | 4117 | |
4eb4cf57 | 4118 | @smallexample |
18fae2a8 | 4119 | (@value{GDBP}) disas fact |
4eb4cf57 RP |
4120 | Dump of assembler code for function fact: |
4121 | to 0x808c: | |
4122 | 0x802c <fact>: 6d f2 mov.w r2,@@-r7 | |
4123 | 0x802e <fact+2>: 6d f3 mov.w r3,@@-r7 | |
4124 | 0x8030 <fact+4>: 6d f6 mov.w r6,@@-r7 | |
4125 | 0x8032 <fact+6>: 0d 76 mov.w r7,r6 | |
4126 | 0x8034 <fact+8>: 6f 70 00 08 mov.w @@(0x8,r7),r0 | |
4127 | 0x8038 <fact+12> 19 11 sub.w r1,r1 | |
4128 | . | |
4129 | . | |
4130 | . | |
4131 | @end smallexample | |
18fae2a8 | 4132 | @end ifset |
4eb4cf57 RP |
4133 | |
4134 | @node Data | |
70b88761 RP |
4135 | @chapter Examining Data |
4136 | ||
4137 | @cindex printing data | |
4138 | @cindex examining data | |
4139 | @kindex print | |
4140 | @kindex inspect | |
1041a570 | 4141 | @c "inspect" is not quite a synonym if you are using Epoch, which we do not |
29a2b744 | 4142 | @c document because it is nonstandard... Under Epoch it displays in a |
70b88761 RP |
4143 | @c different window or something like that. |
4144 | The usual way to examine data in your program is with the @code{print} | |
4eb4cf57 | 4145 | command (abbreviated @code{p}), or its synonym @code{inspect}. |
18fae2a8 | 4146 | @ifclear CONLY |
4eb4cf57 | 4147 | It evaluates and prints the value of an expression of the language your |
18fae2a8 | 4148 | program is written in (@pxref{Languages, ,Using @value{GDBN} with Different |
4eb4cf57 | 4149 | Languages}). |
18fae2a8 | 4150 | @end ifclear |
70b88761 | 4151 | |
e0dacfd1 RP |
4152 | @table @code |
4153 | @item print @var{exp} | |
4154 | @itemx print /@var{f} @var{exp} | |
4155 | @var{exp} is an expression (in the source language). By default | |
70b88761 | 4156 | the value of @var{exp} is printed in a format appropriate to its data |
e0dacfd1 | 4157 | type; you can choose a different format by specifying @samp{/@var{f}}, |
ed447b95 | 4158 | where @var{f} is a letter specifying the format; @pxref{Output Formats}. |
e0dacfd1 RP |
4159 | |
4160 | @item print | |
4161 | @itemx print /@var{f} | |
18fae2a8 | 4162 | If you omit @var{exp}, @value{GDBN} displays the last value again (from the |
1041a570 | 4163 | @dfn{value history}; @pxref{Value History, ,Value History}). This allows you to |
e0dacfd1 RP |
4164 | conveniently inspect the same value in an alternative format. |
4165 | @end table | |
70b88761 RP |
4166 | |
4167 | A more low-level way of examining data is with the @code{x} command. | |
4168 | It examines data in memory at a specified address and prints it in a | |
29a2b744 | 4169 | specified format. @xref{Memory, ,Examining Memory}. |
70b88761 | 4170 | |
29a2b744 | 4171 | If you are interested in information about types, or about how the fields |
b80282d5 | 4172 | of a struct or class are declared, use the @code{ptype @var{exp}} |
1041a570 | 4173 | command rather than @code{print}. @xref{Symbols, ,Examining the Symbol Table}. |
b80282d5 | 4174 | |
18fae2a8 RP |
4175 | @ignore |
4176 | @c pre-unfold | |
4177 | @menu | |
4178 | * Expressions:: Expressions | |
ed447b95 RP |
4179 | * Variables:: Program variables |
4180 | * Arrays:: Artificial arrays | |
18fae2a8 | 4181 | * Output formats:: Output formats |
ed447b95 RP |
4182 | * Memory:: Examining memory |
4183 | * Auto Display:: Automatic display | |
4184 | * Print Settings:: Print settings | |
4185 | * Value History:: Value history | |
4186 | * Convenience Vars:: Convenience variables | |
18fae2a8 RP |
4187 | * Registers:: Registers |
4188 | @ifclear HviiiEXCLUSIVE | |
ed447b95 | 4189 | * Floating Point Hardware:: Floating point hardware |
18fae2a8 RP |
4190 | @end ifclear |
4191 | @end menu | |
4192 | @end ignore | |
4193 | ||
4194 | @ifclear HviiiEXCLUSIVE | |
70b88761 | 4195 | @menu |
b80282d5 | 4196 | * Expressions:: Expressions |
ed447b95 RP |
4197 | * Variables:: Program variables |
4198 | * Arrays:: Artificial arrays | |
b80282d5 | 4199 | * Output formats:: Output formats |
ed447b95 RP |
4200 | * Memory:: Examining memory |
4201 | * Auto Display:: Automatic display | |
4202 | * Print Settings:: Print settings | |
4203 | * Value History:: Value history | |
4204 | * Convenience Vars:: Convenience variables | |
b80282d5 | 4205 | * Registers:: Registers |
ed447b95 | 4206 | * Floating Point Hardware:: Floating point hardware |
70b88761 | 4207 | @end menu |
18fae2a8 RP |
4208 | @end ifclear |
4209 | ||
4210 | @ifset HviiiEXCLUSIVE | |
4211 | @menu | |
4212 | * Expressions:: Expressions | |
ed447b95 RP |
4213 | * Variables:: Program variables |
4214 | * Arrays:: Artificial arrays | |
18fae2a8 | 4215 | * Output formats:: Output formats |
ed447b95 RP |
4216 | * Memory:: Examining memory |
4217 | * Auto Display:: Automatic display | |
4218 | * Print Settings:: Print settings | |
4219 | * Value History:: Value history | |
4220 | * Convenience Vars:: Convenience variables | |
18fae2a8 RP |
4221 | * Registers:: Registers |
4222 | @end menu | |
4223 | @end ifset | |
70b88761 | 4224 | |
4eb4cf57 | 4225 | @node Expressions |
70b88761 RP |
4226 | @section Expressions |
4227 | ||
4228 | @cindex expressions | |
18fae2a8 | 4229 | @code{print} and many other @value{GDBN} commands accept an expression and |
70b88761 RP |
4230 | compute its value. Any kind of constant, variable or operator defined |
4231 | by the programming language you are using is legal in an expression in | |
18fae2a8 | 4232 | @value{GDBN}. This includes conditional expressions, function calls, casts |
70b88761 | 4233 | and string constants. It unfortunately does not include symbols defined |
b80282d5 | 4234 | by preprocessor @code{#define} commands. |
70b88761 | 4235 | |
18fae2a8 | 4236 | @ifclear CONLY |
c2bbbb22 | 4237 | Because C is so widespread, most of the expressions shown in examples in |
18fae2a8 | 4238 | this manual are in C. @xref{Languages, , Using @value{GDBN} with Different |
c2bbbb22 | 4239 | Languages}, for information on how to use expressions in other |
e251e767 | 4240 | languages. |
c2bbbb22 | 4241 | |
18fae2a8 | 4242 | In this section, we discuss operators that you can use in @value{GDBN} |
e251e767 | 4243 | expressions regardless of your programming language. |
c2bbbb22 | 4244 | |
70b88761 RP |
4245 | Casts are supported in all languages, not just in C, because it is so |
4246 | useful to cast a number into a pointer so as to examine a structure | |
4247 | at that address in memory. | |
c2bbbb22 | 4248 | @c FIXME: casts supported---Mod2 true? |
18fae2a8 | 4249 | @end ifclear |
70b88761 | 4250 | |
18fae2a8 | 4251 | @value{GDBN} supports these operators in addition to those of programming |
70b88761 RP |
4252 | languages: |
4253 | ||
4254 | @table @code | |
4255 | @item @@ | |
4256 | @samp{@@} is a binary operator for treating parts of memory as arrays. | |
1041a570 | 4257 | @xref{Arrays, ,Artificial Arrays}, for more information. |
70b88761 RP |
4258 | |
4259 | @item :: | |
4260 | @samp{::} allows you to specify a variable in terms of the file or | |
1041a570 | 4261 | function where it is defined. @xref{Variables, ,Program Variables}. |
70b88761 RP |
4262 | |
4263 | @item @{@var{type}@} @var{addr} | |
4264 | Refers to an object of type @var{type} stored at address @var{addr} in | |
4265 | memory. @var{addr} may be any expression whose value is an integer or | |
4266 | pointer (but parentheses are required around binary operators, just as in | |
4267 | a cast). This construct is allowed regardless of what kind of data is | |
1041a570 | 4268 | normally supposed to reside at @var{addr}. |
70b88761 RP |
4269 | @end table |
4270 | ||
4eb4cf57 | 4271 | @node Variables |
70b88761 RP |
4272 | @section Program Variables |
4273 | ||
4274 | The most common kind of expression to use is the name of a variable | |
4275 | in your program. | |
4276 | ||
4277 | Variables in expressions are understood in the selected stack frame | |
29a2b744 RP |
4278 | (@pxref{Selection, ,Selecting a Frame}); they must either be global |
4279 | (or static) or be visible according to the scope rules of the | |
4280 | programming language from the point of execution in that frame. This | |
4281 | means that in the function | |
70b88761 RP |
4282 | |
4283 | @example | |
4284 | foo (a) | |
4285 | int a; | |
4286 | @{ | |
4287 | bar (a); | |
4288 | @{ | |
4289 | int b = test (); | |
4290 | bar (b); | |
4291 | @} | |
4292 | @} | |
4293 | @end example | |
4294 | ||
4295 | @noindent | |
ed447b95 RP |
4296 | you can examine and use the variable @code{a} whenever your program is |
4297 | executing within the function @code{foo}, but you can only use or | |
4298 | examine the variable @code{b} while your program is executing inside | |
4299 | the block where @code{b} is declared. | |
70b88761 RP |
4300 | |
4301 | @cindex variable name conflict | |
4302 | There is an exception: you can refer to a variable or function whose | |
4303 | scope is a single source file even if the current execution point is not | |
4304 | in this file. But it is possible to have more than one such variable or | |
6ca72cc6 RP |
4305 | function with the same name (in different source files). If that |
4306 | happens, referring to that name has unpredictable effects. If you wish, | |
4307 | you can specify a static variable in a particular function or file, | |
4308 | using the colon-colon notation: | |
70b88761 RP |
4309 | |
4310 | @cindex colon-colon | |
a6d0b6d3 | 4311 | @iftex |
29a2b744 | 4312 | @c info cannot cope with a :: index entry, but why deprive hard copy readers? |
70b88761 | 4313 | @kindex :: |
a6d0b6d3 | 4314 | @end iftex |
70b88761 RP |
4315 | @example |
4316 | @var{file}::@var{variable} | |
6ca72cc6 | 4317 | @var{function}::@var{variable} |
70b88761 RP |
4318 | @end example |
4319 | ||
4320 | @noindent | |
6ca72cc6 | 4321 | Here @var{file} or @var{function} is the name of the context for the |
6c380b13 | 4322 | static @var{variable}. In the case of file names, you can use quotes to |
18fae2a8 | 4323 | make sure @value{GDBN} parses the file name as a single word---for example, |
6c380b13 RP |
4324 | to print a global value of @code{x} defined in @file{f2.c}: |
4325 | ||
4326 | @example | |
18fae2a8 | 4327 | (@value{GDBP}) p 'f2.c'::x |
6c380b13 | 4328 | @end example |
70b88761 | 4329 | |
18fae2a8 | 4330 | @ifclear CONLY |
c2bbbb22 | 4331 | @cindex C++ scope resolution |
70b88761 | 4332 | This use of @samp{::} is very rarely in conflict with the very similar |
18fae2a8 RP |
4333 | use of the same notation in C++. @value{GDBN} also supports use of the C++ |
4334 | scope resolution operator in @value{GDBN} expressions. | |
ed447b95 RP |
4335 | @c FIXME: Um, so what happens in one of those rare cases where it's in |
4336 | @c conflict?? --mew | |
18fae2a8 | 4337 | @end ifclear |
70b88761 | 4338 | |
3d3ab540 RP |
4339 | @cindex wrong values |
4340 | @cindex variable values, wrong | |
4341 | @quotation | |
4342 | @emph{Warning:} Occasionally, a local variable may appear to have the | |
4343 | wrong value at certain points in a function---just after entry to the | |
29a2b744 | 4344 | function, and just before exit. You may see this problem when you are |
3d3ab540 RP |
4345 | stepping by machine instructions. This is because on most machines, it |
4346 | takes more than one instruction to set up a stack frame (including local | |
29a2b744 | 4347 | variable definitions); if you are stepping by machine instructions, |
3d3ab540 RP |
4348 | variables may appear to have the wrong values until the stack frame is |
4349 | completely built. On function exit, it usually also takes more than one | |
4350 | machine instruction to destroy a stack frame; after you begin stepping | |
4351 | through that group of instructions, local variable definitions may be | |
4352 | gone. | |
4353 | @end quotation | |
4354 | ||
4eb4cf57 | 4355 | @node Arrays |
70b88761 RP |
4356 | @section Artificial Arrays |
4357 | ||
4358 | @cindex artificial array | |
4359 | @kindex @@ | |
4360 | It is often useful to print out several successive objects of the | |
4361 | same type in memory; a section of an array, or an array of | |
4362 | dynamically determined size for which only a pointer exists in the | |
4363 | program. | |
4364 | ||
4365 | This can be done by constructing an @dfn{artificial array} with the | |
4366 | binary operator @samp{@@}. The left operand of @samp{@@} should be | |
4367 | the first element of the desired array, as an individual object. | |
4368 | The right operand should be the desired length of the array. The result is | |
4369 | an array value whose elements are all of the type of the left argument. | |
4370 | The first element is actually the left argument; the second element | |
4371 | comes from bytes of memory immediately following those that hold the | |
4372 | first element, and so on. Here is an example. If a program says | |
4373 | ||
4374 | @example | |
4375 | int *array = (int *) malloc (len * sizeof (int)); | |
4376 | @end example | |
4377 | ||
4378 | @noindent | |
4379 | you can print the contents of @code{array} with | |
4380 | ||
4381 | @example | |
4382 | p *array@@len | |
4383 | @end example | |
4384 | ||
4385 | The left operand of @samp{@@} must reside in memory. Array values made | |
4386 | with @samp{@@} in this way behave just like other arrays in terms of | |
4387 | subscripting, and are coerced to pointers when used in expressions. | |
4388 | Artificial arrays most often appear in expressions via the value history | |
1041a570 | 4389 | (@pxref{Value History, ,Value History}), after printing one out.) |
70b88761 | 4390 | |
1041a570 | 4391 | Sometimes the artificial array mechanism is not quite enough; in |
3d3ab540 | 4392 | moderately complex data structures, the elements of interest may not |
1041a570 RP |
4393 | actually be adjacent---for example, if you are interested in the values |
4394 | of pointers in an array. One useful work-around in this situation is | |
4395 | to use a convenience variable (@pxref{Convenience Vars, ,Convenience | |
4396 | Variables}) as a counter in an expression that prints the first | |
4397 | interesting value, and then repeat that expression via @key{RET}. For | |
4398 | instance, suppose you have an array @code{dtab} of pointers to | |
4399 | structures, and you are interested in the values of a field @code{fv} | |
4400 | in each structure. Here is an example of what you might type: | |
4401 | ||
3d3ab540 RP |
4402 | @example |
4403 | set $i = 0 | |
4404 | p dtab[$i++]->fv | |
4405 | @key{RET} | |
4406 | @key{RET} | |
4407 | @dots{} | |
4408 | @end example | |
4409 | ||
ed447b95 | 4410 | @node Output Formats |
70b88761 RP |
4411 | @section Output formats |
4412 | ||
4413 | @cindex formatted output | |
4414 | @cindex output formats | |
18fae2a8 | 4415 | By default, @value{GDBN} prints a value according to its data type. Sometimes |
70b88761 RP |
4416 | this is not what you want. For example, you might want to print a number |
4417 | in hex, or a pointer in decimal. Or you might want to view data in memory | |
4418 | at a certain address as a character string or as an instruction. To do | |
4419 | these things, specify an @dfn{output format} when you print a value. | |
4420 | ||
4421 | The simplest use of output formats is to say how to print a value | |
4422 | already computed. This is done by starting the arguments of the | |
4423 | @code{print} command with a slash and a format letter. The format | |
4424 | letters supported are: | |
4425 | ||
4426 | @table @code | |
4427 | @item x | |
4428 | Regard the bits of the value as an integer, and print the integer in | |
4429 | hexadecimal. | |
4430 | ||
4431 | @item d | |
4432 | Print as integer in signed decimal. | |
4433 | ||
4434 | @item u | |
4435 | Print as integer in unsigned decimal. | |
4436 | ||
4437 | @item o | |
4438 | Print as integer in octal. | |
4439 | ||
4440 | @item t | |
4441 | Print as integer in binary. The letter @samp{t} stands for ``two''. | |
4442 | ||
4443 | @item a | |
4444 | Print as an address, both absolute in hex and as an offset from the | |
4445 | nearest preceding symbol. This format can be used to discover where (in | |
4446 | what function) an unknown address is located: | |
1041a570 | 4447 | |
70b88761 | 4448 | @example |
18fae2a8 RP |
4449 | (@value{GDBP}) p/a 0x54320 |
4450 | $3 = 0x54320 <_initialize_vx+396> | |
70b88761 RP |
4451 | @end example |
4452 | ||
70b88761 RP |
4453 | @item c |
4454 | Regard as an integer and print it as a character constant. | |
4455 | ||
4456 | @item f | |
4457 | Regard the bits of the value as a floating point number and print | |
4458 | using typical floating point syntax. | |
4459 | @end table | |
4460 | ||
4461 | For example, to print the program counter in hex (@pxref{Registers}), type | |
4462 | ||
4463 | @example | |
4464 | p/x $pc | |
4465 | @end example | |
4466 | ||
4467 | @noindent | |
4468 | Note that no space is required before the slash; this is because command | |
18fae2a8 | 4469 | names in @value{GDBN} cannot contain a slash. |
70b88761 RP |
4470 | |
4471 | To reprint the last value in the value history with a different format, | |
4472 | you can use the @code{print} command with just a format and no | |
4473 | expression. For example, @samp{p/x} reprints the last value in hex. | |
4474 | ||
4eb4cf57 | 4475 | @node Memory |
70b88761 RP |
4476 | @section Examining Memory |
4477 | ||
1041a570 RP |
4478 | You can use the command @code{x} (for ``examine'') to examine memory in |
4479 | any of several formats, independently of your program's data types. | |
4480 | ||
70b88761 RP |
4481 | @cindex examining memory |
4482 | @table @code | |
4483 | @kindex x | |
cedaf8bc RP |
4484 | @item x/@var{nfu} @var{addr} |
4485 | @itemx x @var{addr} | |
4486 | @itemx x | |
ed447b95 | 4487 | Use the @code{x} command to examine memory. |
1041a570 RP |
4488 | @end table |
4489 | ||
4490 | @var{n}, @var{f}, and @var{u} are all optional parameters that specify how | |
4491 | much memory to display and how to format it; @var{addr} is an | |
cedaf8bc RP |
4492 | expression giving the address where you want to start displaying memory. |
4493 | If you use defaults for @var{nfu}, you need not type the slash @samp{/}. | |
4494 | Several commands set convenient defaults for @var{addr}. | |
70b88761 | 4495 | |
1041a570 RP |
4496 | @table @r |
4497 | @item @var{n}, the repeat count | |
4498 | The repeat count is a decimal integer; the default is 1. It specifies | |
4499 | how much memory (counting by units @var{u}) to display. | |
cedaf8bc RP |
4500 | @c This really is **decimal**; unaffected by 'set radix' as of GDB |
4501 | @c 4.1.2. | |
70b88761 | 4502 | |
1041a570 RP |
4503 | @item @var{f}, the display format |
4504 | The display format is one of the formats used by @code{print}, | |
cedaf8bc RP |
4505 | or @samp{s} (null-terminated string) or @samp{i} (machine instruction). |
4506 | The default is @samp{x} (hexadecimal) initially, or the format from the | |
4507 | last time you used either @code{x} or @code{print}. | |
70b88761 | 4508 | |
1041a570 RP |
4509 | @item @var{u}, the unit size |
4510 | The unit size is any of | |
ed447b95 | 4511 | |
70b88761 RP |
4512 | @table @code |
4513 | @item b | |
cedaf8bc | 4514 | Bytes. |
70b88761 | 4515 | @item h |
cedaf8bc | 4516 | Halfwords (two bytes). |
70b88761 | 4517 | @item w |
cedaf8bc | 4518 | Words (four bytes). This is the initial default. |
70b88761 | 4519 | @item g |
cedaf8bc | 4520 | Giant words (eight bytes). |
70b88761 RP |
4521 | @end table |
4522 | ||
cedaf8bc RP |
4523 | Each time you specify a unit size with @code{x}, that size becomes the |
4524 | default unit the next time you use @code{x}. (For the @samp{s} and | |
4525 | @samp{i} formats, the unit size is ignored and is normally not written.) | |
4526 | ||
1041a570 | 4527 | @item @var{addr}, starting display address |
18fae2a8 | 4528 | @var{addr} is the address where you want @value{GDBN} to begin displaying |
cedaf8bc RP |
4529 | memory. The expression need not have a pointer value (though it may); |
4530 | it is always interpreted as an integer address of a byte of memory. | |
1041a570 | 4531 | @xref{Expressions, ,Expressions}, for more information on expressions. The default for |
cedaf8bc RP |
4532 | @var{addr} is usually just after the last address examined---but several |
4533 | other commands also set the default address: @code{info breakpoints} (to | |
4534 | the address of the last breakpoint listed), @code{info line} (to the | |
4535 | starting address of a line), and @code{print} (if you use it to display | |
4536 | a value from memory). | |
1041a570 | 4537 | @end table |
70b88761 | 4538 | |
cedaf8bc RP |
4539 | For example, @samp{x/3uh 0x54320} is a request to display three halfwords |
4540 | (@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}), | |
4541 | starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four | |
4542 | words (@samp{w}) of memory above the stack pointer (here, @samp{$sp}; | |
4543 | @pxref{Registers}) in hexadecimal (@samp{x}). | |
70b88761 | 4544 | |
cedaf8bc | 4545 | Since the letters indicating unit sizes are all distinct from the |
29a2b744 | 4546 | letters specifying output formats, you do not have to remember whether |
cedaf8bc RP |
4547 | unit size or format comes first; either order will work. The output |
4548 | specifications @samp{4xw} and @samp{4wx} mean exactly the same thing. | |
4549 | (However, the count @var{n} must come first; @samp{wx4} will not work.) | |
4550 | ||
4551 | Even though the unit size @var{u} is ignored for the formats @samp{s} | |
4552 | and @samp{i}, you might still want to use a count @var{n}; for example, | |
4553 | @samp{3i} specifies that you want to see three machine instructions, | |
4554 | including any operands. The command @code{disassemble} gives an | |
4555 | alternative way of inspecting machine instructions; @pxref{Machine | |
4556 | Code}. | |
4557 | ||
4558 | All the defaults for the arguments to @code{x} are designed to make it | |
4559 | easy to continue scanning memory with minimal specifications each time | |
1041a570 | 4560 | you use @code{x}. For example, after you have inspected three machine |
cedaf8bc RP |
4561 | instructions with @samp{x/3i @var{addr}}, you can inspect the next seven |
4562 | with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command, | |
4563 | the repeat count @var{n} is used again; the other arguments default as | |
4564 | for successive uses of @code{x}. | |
70b88761 | 4565 | |
c338a2fd | 4566 | @cindex @code{$_}, @code{$__}, and value history |
cedaf8bc | 4567 | The addresses and contents printed by the @code{x} command are not saved |
70b88761 | 4568 | in the value history because there is often too much of them and they |
18fae2a8 | 4569 | would get in the way. Instead, @value{GDBN} makes these values available for |
70b88761 RP |
4570 | subsequent use in expressions as values of the convenience variables |
4571 | @code{$_} and @code{$__}. After an @code{x} command, the last address | |
4572 | examined is available for use in expressions in the convenience variable | |
4573 | @code{$_}. The contents of that address, as examined, are available in | |
4574 | the convenience variable @code{$__}. | |
4575 | ||
4576 | If the @code{x} command has a repeat count, the address and contents saved | |
4577 | are from the last memory unit printed; this is not the same as the last | |
4578 | address printed if several units were printed on the last line of output. | |
4579 | ||
4eb4cf57 | 4580 | @node Auto Display |
70b88761 RP |
4581 | @section Automatic Display |
4582 | @cindex automatic display | |
4583 | @cindex display of expressions | |
4584 | ||
4585 | If you find that you want to print the value of an expression frequently | |
4586 | (to see how it changes), you might want to add it to the @dfn{automatic | |
18fae2a8 | 4587 | display list} so that @value{GDBN} will print its value each time your program stops. |
70b88761 RP |
4588 | Each expression added to the list is given a number to identify it; |
4589 | to remove an expression from the list, you specify that number. | |
4590 | The automatic display looks like this: | |
4591 | ||
4592 | @example | |
4593 | 2: foo = 38 | |
4594 | 3: bar[5] = (struct hack *) 0x3804 | |
4595 | @end example | |
4596 | ||
4597 | @noindent | |
ed447b95 | 4598 | This display shows item numbers, expressions and their current values. As with |
70b88761 RP |
4599 | displays you request manually using @code{x} or @code{print}, you can |
4600 | specify the output format you prefer; in fact, @code{display} decides | |
4601 | whether to use @code{print} or @code{x} depending on how elaborate your | |
4602 | format specification is---it uses @code{x} if you specify a unit size, | |
4603 | or one of the two formats (@samp{i} and @samp{s}) that are only | |
4604 | supported by @code{x}; otherwise it uses @code{print}. | |
4605 | ||
4606 | @table @code | |
4607 | @item display @var{exp} | |
4608 | @kindex display | |
4609 | Add the expression @var{exp} to the list of expressions to display | |
1041a570 | 4610 | each time your program stops. @xref{Expressions, ,Expressions}. |
70b88761 RP |
4611 | |
4612 | @code{display} will not repeat if you press @key{RET} again after using it. | |
4613 | ||
4614 | @item display/@var{fmt} @var{exp} | |
4615 | For @var{fmt} specifying only a display format and not a size or | |
4616 | count, add the expression @var{exp} to the auto-display list but | |
4617 | arranges to display it each time in the specified format @var{fmt}. | |
ed447b95 | 4618 | @xref{Output Formats,,Output formats}. |
70b88761 RP |
4619 | |
4620 | @item display/@var{fmt} @var{addr} | |
4621 | For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a | |
4622 | number of units, add the expression @var{addr} as a memory address to | |
29a2b744 RP |
4623 | be examined each time your program stops. Examining means in effect |
4624 | doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining Memory}. | |
70b88761 RP |
4625 | @end table |
4626 | ||
4627 | For example, @samp{display/i $pc} can be helpful, to see the machine | |
4628 | instruction about to be executed each time execution stops (@samp{$pc} | |
4629 | is a common name for the program counter; @pxref{Registers}). | |
4630 | ||
4631 | @table @code | |
4632 | @item undisplay @var{dnums}@dots{} | |
4633 | @itemx delete display @var{dnums}@dots{} | |
4634 | @kindex delete display | |
4635 | @kindex undisplay | |
4636 | Remove item numbers @var{dnums} from the list of expressions to display. | |
4637 | ||
4638 | @code{undisplay} will not repeat if you press @key{RET} after using it. | |
4639 | (Otherwise you would just get the error @samp{No display number @dots{}}.) | |
4640 | ||
4641 | @item disable display @var{dnums}@dots{} | |
4642 | @kindex disable display | |
4643 | Disable the display of item numbers @var{dnums}. A disabled display | |
4644 | item is not printed automatically, but is not forgotten. It may be | |
4645 | enabled again later. | |
4646 | ||
4647 | @item enable display @var{dnums}@dots{} | |
4648 | @kindex enable display | |
4649 | Enable display of item numbers @var{dnums}. It becomes effective once | |
4650 | again in auto display of its expression, until you specify otherwise. | |
4651 | ||
4652 | @item display | |
4653 | Display the current values of the expressions on the list, just as is | |
29a2b744 | 4654 | done when your program stops. |
70b88761 RP |
4655 | |
4656 | @item info display | |
4657 | @kindex info display | |
4658 | Print the list of expressions previously set up to display | |
4659 | automatically, each one with its item number, but without showing the | |
4660 | values. This includes disabled expressions, which are marked as such. | |
4661 | It also includes expressions which would not be displayed right now | |
4662 | because they refer to automatic variables not currently available. | |
4663 | @end table | |
4664 | ||
4665 | If a display expression refers to local variables, then it does not make | |
4666 | sense outside the lexical context for which it was set up. Such an | |
4667 | expression is disabled when execution enters a context where one of its | |
4668 | variables is not defined. For example, if you give the command | |
4669 | @code{display last_char} while inside a function with an argument | |
29a2b744 | 4670 | @code{last_char}, then this argument will be displayed while your program |
70b88761 RP |
4671 | continues to stop inside that function. When it stops elsewhere---where |
4672 | there is no variable @code{last_char}---display is disabled. The next time | |
4673 | your program stops where @code{last_char} is meaningful, you can enable the | |
4674 | display expression once again. | |
4675 | ||
4eb4cf57 | 4676 | @node Print Settings |
70b88761 RP |
4677 | @section Print Settings |
4678 | ||
4679 | @cindex format options | |
4680 | @cindex print settings | |
18fae2a8 | 4681 | @value{GDBN} provides the following ways to control how arrays, structures, |
e251e767 | 4682 | and symbols are printed. |
70b88761 RP |
4683 | |
4684 | @noindent | |
4685 | These settings are useful for debugging programs in any language: | |
4686 | ||
4687 | @table @code | |
4688 | @item set print address | |
4689 | @item set print address on | |
4690 | @kindex set print address | |
18fae2a8 | 4691 | @value{GDBN} will print memory addresses showing the location of stack |
70b88761 RP |
4692 | traces, structure values, pointer values, breakpoints, and so forth, |
4693 | even when it also displays the contents of those addresses. The default | |
4694 | is on. For example, this is what a stack frame display looks like, with | |
4695 | @code{set print address on}: | |
1041a570 | 4696 | |
70b88761 | 4697 | @smallexample |
1041a570 | 4698 | @group |
18fae2a8 | 4699 | (@value{GDBP}) f |
e251e767 | 4700 | #0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>") |
70b88761 | 4701 | at input.c:530 |
b80282d5 | 4702 | 530 if (lquote != def_lquote) |
1041a570 | 4703 | @end group |
70b88761 RP |
4704 | @end smallexample |
4705 | ||
4706 | @item set print address off | |
4707 | Do not print addresses when displaying their contents. For example, | |
4708 | this is the same stack frame displayed with @code{set print address off}: | |
1041a570 | 4709 | |
70b88761 | 4710 | @example |
1041a570 | 4711 | @group |
18fae2a8 RP |
4712 | (@value{GDBP}) set print addr off |
4713 | (@value{GDBP}) f | |
70b88761 | 4714 | #0 set_quotes (lq="<<", rq=">>") at input.c:530 |
b80282d5 | 4715 | 530 if (lquote != def_lquote) |
1041a570 | 4716 | @end group |
70b88761 RP |
4717 | @end example |
4718 | ||
4719 | @item show print address | |
4720 | @kindex show print address | |
4721 | Show whether or not addresses are to be printed. | |
4722 | ||
4723 | @item set print array | |
4724 | @itemx set print array on | |
4725 | @kindex set print array | |
18fae2a8 | 4726 | @value{GDBN} will pretty print arrays. This format is more convenient to read, |
70b88761 RP |
4727 | but uses more space. The default is off. |
4728 | ||
4729 | @item set print array off. | |
4730 | Return to compressed format for arrays. | |
4731 | ||
4732 | @item show print array | |
4733 | @kindex show print array | |
4734 | Show whether compressed or pretty format is selected for displaying | |
e251e767 | 4735 | arrays. |
70b88761 RP |
4736 | |
4737 | @item set print elements @var{number-of-elements} | |
4738 | @kindex set print elements | |
18fae2a8 | 4739 | If @value{GDBN} is printing a large array, it will stop printing after it has |
70b88761 RP |
4740 | printed the number of elements set by the @code{set print elements} command. |
4741 | This limit also applies to the display of strings. | |
4742 | ||
4743 | @item show print elements | |
4744 | @kindex show print elements | |
18fae2a8 | 4745 | Display the number of elements of a large array that @value{GDBN} will print |
70b88761 RP |
4746 | before losing patience. |
4747 | ||
4748 | @item set print pretty on | |
4749 | @kindex set print pretty | |
18fae2a8 | 4750 | Cause @value{GDBN} to print structures in an indented format with one member per |
70b88761 RP |
4751 | line, like this: |
4752 | ||
4753 | @example | |
1041a570 | 4754 | @group |
70b88761 RP |
4755 | $1 = @{ |
4756 | next = 0x0, | |
4757 | flags = @{ | |
4758 | sweet = 1, | |
4759 | sour = 1 | |
4760 | @}, | |
4761 | meat = 0x54 "Pork" | |
4762 | @} | |
1041a570 | 4763 | @end group |
70b88761 RP |
4764 | @end example |
4765 | ||
4766 | @item set print pretty off | |
18fae2a8 | 4767 | Cause @value{GDBN} to print structures in a compact format, like this: |
70b88761 RP |
4768 | |
4769 | @smallexample | |
1041a570 | 4770 | @group |
38962738 RP |
4771 | $1 = @{next = 0x0, flags = @{sweet = 1, sour = 1@}, \ |
4772 | meat = 0x54 "Pork"@} | |
1041a570 | 4773 | @end group |
70b88761 RP |
4774 | @end smallexample |
4775 | ||
4776 | @noindent | |
4777 | This is the default format. | |
4778 | ||
4779 | @item show print pretty | |
4780 | @kindex show print pretty | |
18fae2a8 | 4781 | Show which format @value{GDBN} will use to print structures. |
70b88761 RP |
4782 | |
4783 | @item set print sevenbit-strings on | |
f2857bd9 | 4784 | @kindex set print sevenbit-strings |
e251e767 | 4785 | Print using only seven-bit characters; if this option is set, |
18fae2a8 | 4786 | @value{GDBN} will display any eight-bit characters (in strings or character |
70b88761 RP |
4787 | values) using the notation @code{\}@var{nnn}. For example, @kbd{M-a} is |
4788 | displayed as @code{\341}. | |
4789 | ||
4790 | @item set print sevenbit-strings off | |
4791 | Print using either seven-bit or eight-bit characters, as required. This | |
4792 | is the default. | |
4793 | ||
4794 | @item show print sevenbit-strings | |
f2857bd9 | 4795 | @kindex show print sevenbit-strings |
18fae2a8 | 4796 | Show whether or not @value{GDBN} will print only seven-bit characters. |
70b88761 RP |
4797 | |
4798 | @item set print union on | |
4799 | @kindex set print union | |
18fae2a8 | 4800 | Tell @value{GDBN} to print unions which are contained in structures. This is the |
70b88761 RP |
4801 | default setting. |
4802 | ||
4803 | @item set print union off | |
18fae2a8 | 4804 | Tell @value{GDBN} not to print unions which are contained in structures. |
70b88761 RP |
4805 | |
4806 | @item show print union | |
4807 | @kindex show print union | |
18fae2a8 | 4808 | Ask @value{GDBN} whether or not it will print unions which are contained in |
e251e767 | 4809 | structures. |
70b88761 RP |
4810 | |
4811 | For example, given the declarations | |
4812 | ||
4813 | @smallexample | |
4814 | typedef enum @{Tree, Bug@} Species; | |
4815 | typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms; | |
203eea5d RP |
4816 | typedef enum @{Caterpillar, Cocoon, Butterfly@} |
4817 | Bug_forms; | |
70b88761 RP |
4818 | |
4819 | struct thing @{ | |
4820 | Species it; | |
4821 | union @{ | |
4822 | Tree_forms tree; | |
4823 | Bug_forms bug; | |
4824 | @} form; | |
4825 | @}; | |
4826 | ||
4827 | struct thing foo = @{Tree, @{Acorn@}@}; | |
4828 | @end smallexample | |
4829 | ||
4830 | @noindent | |
4831 | with @code{set print union on} in effect @samp{p foo} would print | |
4832 | ||
4833 | @smallexample | |
4834 | $1 = @{it = Tree, form = @{tree = Acorn, bug = Cocoon@}@} | |
4835 | @end smallexample | |
4836 | ||
4837 | @noindent | |
4838 | and with @code{set print union off} in effect it would print | |
4839 | ||
4840 | @smallexample | |
4841 | $1 = @{it = Tree, form = @{...@}@} | |
4842 | @end smallexample | |
4843 | @end table | |
4844 | ||
4845 | @noindent | |
4846 | These settings are of interest when debugging C++ programs: | |
4847 | ||
4848 | @table @code | |
e251e767 RP |
4849 | @item set print demangle |
4850 | @itemx set print demangle on | |
70b88761 RP |
4851 | @kindex set print demangle |
4852 | Print C++ names in their source form rather than in the mangled form | |
4853 | in which they are passed to the assembler and linker for type-safe linkage. | |
4854 | The default is on. | |
4855 | ||
4856 | @item show print demangle | |
4857 | @kindex show print demangle | |
4858 | Show whether C++ names will be printed in mangled or demangled form. | |
4859 | ||
e251e767 RP |
4860 | @item set print asm-demangle |
4861 | @itemx set print asm-demangle on | |
70b88761 RP |
4862 | @kindex set print asm-demangle |
4863 | Print C++ names in their source form rather than their mangled form, even | |
4864 | in assembler code printouts such as instruction disassemblies. | |
4865 | The default is off. | |
4866 | ||
4867 | @item show print asm-demangle | |
4868 | @kindex show print asm-demangle | |
4869 | Show whether C++ names in assembly listings will be printed in mangled | |
4870 | or demangled form. | |
4871 | ||
4872 | @item set print object | |
4873 | @itemx set print object on | |
4874 | @kindex set print object | |
4875 | When displaying a pointer to an object, identify the @emph{actual} | |
4876 | (derived) type of the object rather than the @emph{declared} type, using | |
4877 | the virtual function table. | |
4878 | ||
4879 | @item set print object off | |
4880 | Display only the declared type of objects, without reference to the | |
4881 | virtual function table. This is the default setting. | |
4882 | ||
4883 | @item show print object | |
4884 | @kindex show print object | |
4885 | Show whether actual, or declared, object types will be displayed. | |
4886 | ||
e251e767 RP |
4887 | @item set print vtbl |
4888 | @itemx set print vtbl on | |
70b88761 RP |
4889 | @kindex set print vtbl |
4890 | Pretty print C++ virtual function tables. The default is off. | |
4891 | ||
4892 | @item set print vtbl off | |
4893 | Do not pretty print C++ virtual function tables. | |
4894 | ||
4895 | @item show print vtbl | |
4896 | @kindex show print vtbl | |
4897 | Show whether C++ virtual function tables are pretty printed, or not. | |
70b88761 RP |
4898 | @end table |
4899 | ||
4eb4cf57 | 4900 | @node Value History |
70b88761 RP |
4901 | @section Value History |
4902 | ||
4903 | @cindex value history | |
18fae2a8 | 4904 | Values printed by the @code{print} command are saved in @value{GDBN}'s @dfn{value |
70b88761 RP |
4905 | history} so that you can refer to them in other expressions. Values are |
4906 | kept until the symbol table is re-read or discarded (for example with | |
4907 | the @code{file} or @code{symbol-file} commands). When the symbol table | |
4908 | changes, the value history is discarded, since the values may contain | |
4909 | pointers back to the types defined in the symbol table. | |
4910 | ||
4911 | @cindex @code{$} | |
4912 | @cindex @code{$$} | |
4913 | @cindex history number | |
4914 | The values printed are given @dfn{history numbers} for you to refer to them | |
4915 | by. These are successive integers starting with one. @code{print} shows you | |
4916 | the history number assigned to a value by printing @samp{$@var{num} = } | |
4917 | before the value; here @var{num} is the history number. | |
4918 | ||
4919 | To refer to any previous value, use @samp{$} followed by the value's | |
4920 | history number. The way @code{print} labels its output is designed to | |
4921 | remind you of this. Just @code{$} refers to the most recent value in | |
4922 | the history, and @code{$$} refers to the value before that. | |
4923 | @code{$$@var{n}} refers to the @var{n}th value from the end; @code{$$2} | |
4924 | is the value just prior to @code{$$}, @code{$$1} is equivalent to | |
4925 | @code{$$}, and @code{$$0} is equivalent to @code{$}. | |
4926 | ||
4927 | For example, suppose you have just printed a pointer to a structure and | |
4928 | want to see the contents of the structure. It suffices to type | |
4929 | ||
4930 | @example | |
4931 | p *$ | |
4932 | @end example | |
4933 | ||
4934 | If you have a chain of structures where the component @code{next} points | |
4935 | to the next one, you can print the contents of the next one with this: | |
4936 | ||
4937 | @example | |
4938 | p *$.next | |
4939 | @end example | |
4940 | ||
4941 | @noindent | |
4942 | You can print successive links in the chain by repeating this | |
4943 | command---which you can do by just typing @key{RET}. | |
4944 | ||
4945 | Note that the history records values, not expressions. If the value of | |
4946 | @code{x} is 4 and you type these commands: | |
4947 | ||
4948 | @example | |
4949 | print x | |
4950 | set x=5 | |
4951 | @end example | |
4952 | ||
4953 | @noindent | |
4954 | then the value recorded in the value history by the @code{print} command | |
4955 | remains 4 even though the value of @code{x} has changed. | |
4956 | ||
4957 | @table @code | |
4958 | @kindex show values | |
4959 | @item show values | |
4960 | Print the last ten values in the value history, with their item numbers. | |
4961 | This is like @samp{p@ $$9} repeated ten times, except that @code{show | |
4962 | values} does not change the history. | |
4963 | ||
4964 | @item show values @var{n} | |
4965 | Print ten history values centered on history item number @var{n}. | |
4966 | ||
4967 | @item show values + | |
4968 | Print ten history values just after the values last printed. If no more | |
4969 | values are available, produces no display. | |
4970 | @end table | |
4971 | ||
4972 | Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the | |
e251e767 | 4973 | same effect as @samp{show values +}. |
70b88761 | 4974 | |
4eb4cf57 | 4975 | @node Convenience Vars |
70b88761 RP |
4976 | @section Convenience Variables |
4977 | ||
4978 | @cindex convenience variables | |
18fae2a8 RP |
4979 | @value{GDBN} provides @dfn{convenience variables} that you can use within |
4980 | @value{GDBN} to hold on to a value and refer to it later. These variables | |
4981 | exist entirely within @value{GDBN}; they are not part of your program, and | |
70b88761 | 4982 | setting a convenience variable has no direct effect on further execution |
1041a570 | 4983 | of your program. That is why you can use them freely. |
70b88761 RP |
4984 | |
4985 | Convenience variables are prefixed with @samp{$}. Any name preceded by | |
4986 | @samp{$} can be used for a convenience variable, unless it is one of | |
4987 | the predefined machine-specific register names (@pxref{Registers}). | |
4988 | (Value history references, in contrast, are @emph{numbers} preceded | |
1041a570 | 4989 | by @samp{$}. @xref{Value History, ,Value History}.) |
70b88761 RP |
4990 | |
4991 | You can save a value in a convenience variable with an assignment | |
ed447b95 RP |
4992 | expression, just as you would set a variable in your program. |
4993 | For example: | |
70b88761 RP |
4994 | |
4995 | @example | |
4996 | set $foo = *object_ptr | |
4997 | @end example | |
4998 | ||
4999 | @noindent | |
5000 | would save in @code{$foo} the value contained in the object pointed to by | |
5001 | @code{object_ptr}. | |
5002 | ||
5003 | Using a convenience variable for the first time creates it; but its value | |
5004 | is @code{void} until you assign a new value. You can alter the value with | |
5005 | another assignment at any time. | |
5006 | ||
5007 | Convenience variables have no fixed types. You can assign a convenience | |
5008 | variable any type of value, including structures and arrays, even if | |
5009 | that variable already has a value of a different type. The convenience | |
5010 | variable, when used as an expression, has the type of its current value. | |
5011 | ||
5012 | @table @code | |
5013 | @item show convenience | |
5014 | @kindex show convenience | |
5015 | Print a list of convenience variables used so far, and their values. | |
5016 | Abbreviated @code{show con}. | |
5017 | @end table | |
5018 | ||
5019 | One of the ways to use a convenience variable is as a counter to be | |
5020 | incremented or a pointer to be advanced. For example, to print | |
5021 | a field from successive elements of an array of structures: | |
5022 | ||
18fae2a8 | 5023 | @example |
70b88761 RP |
5024 | set $i = 0 |
5025 | print bar[$i++]->contents | |
5026 | @i{@dots{} repeat that command by typing @key{RET}.} | |
18fae2a8 | 5027 | @end example |
70b88761 | 5028 | |
18fae2a8 | 5029 | Some convenience variables are created automatically by @value{GDBN} and given |
70b88761 RP |
5030 | values likely to be useful. |
5031 | ||
5032 | @table @code | |
5033 | @item $_ | |
c338a2fd | 5034 | @kindex $_ |
70b88761 | 5035 | The variable @code{$_} is automatically set by the @code{x} command to |
29a2b744 RP |
5036 | the last address examined (@pxref{Memory, ,Examining Memory}). Other |
5037 | commands which provide a default address for @code{x} to examine also | |
5038 | set @code{$_} to that address; these commands include @code{info line} | |
5039 | and @code{info breakpoint}. The type of @code{$_} is @code{void *} | |
5040 | except when set by the @code{x} command, in which case it is a pointer | |
5041 | to the type of @code{$__}. | |
70b88761 RP |
5042 | |
5043 | @item $__ | |
c338a2fd | 5044 | @kindex $__ |
70b88761 | 5045 | The variable @code{$__} is automatically set by the @code{x} command |
c2bbbb22 RP |
5046 | to the value found in the last address examined. Its type is chosen |
5047 | to match the format in which the data was printed. | |
70b88761 RP |
5048 | @end table |
5049 | ||
4eb4cf57 | 5050 | @node Registers |
70b88761 RP |
5051 | @section Registers |
5052 | ||
5053 | @cindex registers | |
b80282d5 | 5054 | You can refer to machine register contents, in expressions, as variables |
70b88761 RP |
5055 | with names starting with @samp{$}. The names of registers are different |
5056 | for each machine; use @code{info registers} to see the names used on | |
e251e767 | 5057 | your machine. |
70b88761 RP |
5058 | |
5059 | @table @code | |
5060 | @item info registers | |
5061 | @kindex info registers | |
b80282d5 RP |
5062 | Print the names and values of all registers except floating-point |
5063 | registers (in the selected stack frame). | |
5064 | ||
5065 | @item info all-registers | |
5066 | @kindex info all-registers | |
5067 | @cindex floating point registers | |
5068 | Print the names and values of all registers, including floating-point | |
5069 | registers. | |
70b88761 | 5070 | |
4eb4cf57 | 5071 | @item info registers @var{regname} @dots{} |
0d1cd01e JG |
5072 | Print the relativized value of each specified register @var{regname}. |
5073 | @var{regname} may be any register name valid on the machine you are using, with | |
70b88761 RP |
5074 | or without the initial @samp{$}. |
5075 | @end table | |
5076 | ||
18fae2a8 | 5077 | @value{GDBN} has four ``standard'' register names that are available (in |
29a2b744 | 5078 | expressions) on most machines---whenever they do not conflict with an |
09267865 RP |
5079 | architecture's canonical mnemonics for registers. The register names |
5080 | @code{$pc} and @code{$sp} are used for the program counter register and | |
5081 | the stack pointer. @code{$fp} is used for a register that contains a | |
5082 | pointer to the current stack frame, and @code{$ps} is used for a | |
5083 | register that contains the processor status. For example, | |
70b88761 | 5084 | you could print the program counter in hex with |
1041a570 | 5085 | |
70b88761 RP |
5086 | @example |
5087 | p/x $pc | |
5088 | @end example | |
5089 | ||
5090 | @noindent | |
5091 | or print the instruction to be executed next with | |
1041a570 | 5092 | |
70b88761 RP |
5093 | @example |
5094 | x/i $pc | |
5095 | @end example | |
5096 | ||
5097 | @noindent | |
ed447b95 | 5098 | or add four to the stack pointer@footnote{This is a way of removing |
29a2b744 RP |
5099 | one word from the stack, on machines where stacks grow downward in |
5100 | memory (most machines, nowadays). This assumes that the innermost | |
5101 | stack frame is selected; setting @code{$sp} is not allowed when other | |
5102 | stack frames are selected. To pop entire frames off the stack, | |
5103 | regardless of machine architecture, use @code{return}; | |
1041a570 RP |
5104 | @pxref{Returning, ,Returning from a Function}.} with |
5105 | ||
70b88761 RP |
5106 | @example |
5107 | set $sp += 4 | |
5108 | @end example | |
5109 | ||
09267865 RP |
5110 | Whenever possible, these four standard register names are available on |
5111 | your machine even though the machine has different canonical mnemonics, | |
5112 | so long as there is no conflict. The @code{info registers} command | |
5113 | shows the canonical names. For example, on the SPARC, @code{info | |
70b88761 RP |
5114 | registers} displays the processor status register as @code{$psr} but you |
5115 | can also refer to it as @code{$ps}. | |
5116 | ||
18fae2a8 | 5117 | @value{GDBN} always considers the contents of an ordinary register as an |
70b88761 RP |
5118 | integer when the register is examined in this way. Some machines have |
5119 | special registers which can hold nothing but floating point; these | |
5120 | registers are considered to have floating point values. There is no way | |
5121 | to refer to the contents of an ordinary register as floating point value | |
5122 | (although you can @emph{print} it as a floating point value with | |
5123 | @samp{print/f $@var{regname}}). | |
5124 | ||
5125 | Some registers have distinct ``raw'' and ``virtual'' data formats. This | |
5126 | means that the data format in which the register contents are saved by | |
5127 | the operating system is not the same one that your program normally | |
5128 | sees. For example, the registers of the 68881 floating point | |
5129 | coprocessor are always saved in ``extended'' (raw) format, but all C | |
5130 | programs expect to work with ``double'' (virtual) format. In such | |
18fae2a8 | 5131 | cases, @value{GDBN} normally works with the virtual format only (the format that |
70b88761 RP |
5132 | makes sense for your program), but the @code{info registers} command |
5133 | prints the data in both formats. | |
5134 | ||
5135 | Normally, register values are relative to the selected stack frame | |
29a2b744 RP |
5136 | (@pxref{Selection, ,Selecting a Frame}). This means that you get the |
5137 | value that the register would contain if all stack frames farther in | |
5138 | were exited and their saved registers restored. In order to see the | |
5139 | true contents of hardware registers, you must select the innermost | |
5140 | frame (with @samp{frame 0}). | |
70b88761 | 5141 | |
18fae2a8 | 5142 | However, @value{GDBN} must deduce where registers are saved, from the machine |
70b88761 | 5143 | code generated by your compiler. If some registers are not saved, or if |
18fae2a8 | 5144 | @value{GDBN} is unable to locate the saved registers, the selected stack |
70b88761 RP |
5145 | frame will make no difference. |
5146 | ||
18fae2a8 | 5147 | @ifset AMDxxixK |
03a77779 | 5148 | @table @code |
d8a68b28 JG |
5149 | @item set rstack_high_address @var{address} |
5150 | @kindex set rstack_high_address | |
03a77779 RP |
5151 | @cindex AMD 29K register stack |
5152 | @cindex register stack, AMD29K | |
5153 | On AMD 29000 family processors, registers are saved in a separate | |
18fae2a8 RP |
5154 | ``register stack''. There is no way for @value{GDBN} to determine the extent |
5155 | of this stack. Normally, @value{GDBN} just assumes that the stack is ``large | |
5156 | enough''. This may result in @value{GDBN} referencing memory locations that | |
03a77779 RP |
5157 | don't exist. If necessary, you can get around this problem by |
5158 | specifying the ending address of the register stack with the @code{set | |
5159 | rstack_high_address} command. The argument should be an address, which | |
5160 | you will probably want to precede with @samp{0x} to specify in | |
5161 | hexadecimal. | |
d8a68b28 JG |
5162 | |
5163 | @item show rstack_high_address | |
5164 | @kindex show rstack_high_address | |
03a77779 RP |
5165 | Display the current limit of the register stack, on AMD 29000 family |
5166 | processors. | |
5167 | @end table | |
18fae2a8 | 5168 | @end ifset |
d8a68b28 | 5169 | |
18fae2a8 | 5170 | @ifclear HviiiEXCLUSIVE |
4eb4cf57 | 5171 | @node Floating Point Hardware |
70b88761 RP |
5172 | @section Floating Point Hardware |
5173 | @cindex floating point | |
1041a570 | 5174 | |
18fae2a8 | 5175 | Depending on the host machine architecture, @value{GDBN} may be able to give |
70b88761 RP |
5176 | you more information about the status of the floating point hardware. |
5177 | ||
5178 | @table @code | |
5179 | @item info float | |
5180 | @kindex info float | |
5181 | If available, provides hardware-dependent information about the floating | |
5182 | point unit. The exact contents and layout vary depending on the | |
5183 | floating point chip. | |
5184 | @end table | |
5185 | @c FIXME: this is a cop-out. Try to get examples, explanations. Only | |
e251e767 RP |
5186 | @c FIXME...supported currently on arm's and 386's. Mark properly with |
5187 | @c FIXME... m4 macros to isolate general statements from hardware-dep, | |
70b88761 | 5188 | @c FIXME... at that point. |
18fae2a8 | 5189 | @end ifclear |
70b88761 | 5190 | |
18fae2a8 | 5191 | @ifclear CONLY |
4eb4cf57 | 5192 | @node Languages |
18fae2a8 | 5193 | @chapter Using @value{GDBN} with Different Languages |
c2bbbb22 RP |
5194 | @cindex languages |
5195 | ||
5196 | Although programming languages generally have common aspects, they are | |
5197 | rarely expressed in the same manner. For instance, in ANSI C, | |
5198 | dereferencing a pointer @code{p} is accomplished by @code{*p}, but in | |
5199 | Modula-2, it is accomplished by @code{p^}. Values can also be | |
5200 | represented (and displayed) differently. Hex numbers in C are written | |
5201 | like @samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}. | |
5202 | ||
5203 | @cindex working language | |
18fae2a8 | 5204 | Language-specific information is built into @value{GDBN} for some languages, |
29a2b744 | 5205 | allowing you to express operations like the above in your program's |
18fae2a8 | 5206 | native language, and allowing @value{GDBN} to output values in a manner |
29a2b744 | 5207 | consistent with the syntax of your program's native language. The |
c2bbbb22 | 5208 | language you use to build expressions, called the @dfn{working |
18fae2a8 | 5209 | language}, can be selected manually, or @value{GDBN} can set it |
c2bbbb22 RP |
5210 | automatically. |
5211 | ||
5212 | @menu | |
5213 | * Setting:: Switching between source languages | |
5214 | * Show:: Displaying the language | |
ed447b95 | 5215 | * Checks:: Type and range checks |
c2bbbb22 RP |
5216 | * Support:: Supported languages |
5217 | @end menu | |
5218 | ||
4eb4cf57 | 5219 | @node Setting |
c2bbbb22 RP |
5220 | @section Switching between source languages |
5221 | ||
18fae2a8 | 5222 | There are two ways to control the working language---either have @value{GDBN} |
c2bbbb22 | 5223 | set it automatically, or select it manually yourself. You can use the |
18fae2a8 | 5224 | @code{set language} command for either purpose. On startup, @value{GDBN} |
c2bbbb22 RP |
5225 | defaults to setting the language automatically. |
5226 | ||
5227 | @menu | |
5228 | * Manually:: Setting the working language manually | |
18fae2a8 | 5229 | * Automatically:: Having @value{GDBN} infer the source language |
c2bbbb22 RP |
5230 | @end menu |
5231 | ||
4eb4cf57 | 5232 | @node Manually |
c2bbbb22 RP |
5233 | @subsection Setting the working language |
5234 | ||
ed447b95 RP |
5235 | If you allow @value{GDBN} to set the language automatically, |
5236 | expressions are interpreted the same way in your debugging session and | |
5237 | your program. | |
5238 | ||
c2bbbb22 | 5239 | @kindex set language |
ed447b95 RP |
5240 | If you wish, you may set the language manually. To do this, issue the |
5241 | command @samp{set language @var{lang}}, where @var{lang} is the name of | |
5242 | a language, such as @code{c} or @code{modula-2}. For a list of the supported | |
5243 | languages, type @samp{set language}. | |
5244 | @c FIXME: rms: eventually this command should be "help set language". | |
c2bbbb22 | 5245 | |
18fae2a8 | 5246 | Setting the language manually prevents @value{GDBN} from updating the working |
c2bbbb22 RP |
5247 | language automatically. This can lead to confusion if you try |
5248 | to debug a program when the working language is not the same as the | |
5249 | source language, when an expression is acceptable to both | |
5250 | languages---but means different things. For instance, if the current | |
18fae2a8 | 5251 | source file were written in C, and @value{GDBN} was parsing Modula-2, a |
c2bbbb22 RP |
5252 | command such as: |
5253 | ||
5254 | @example | |
5255 | print a = b + c | |
5256 | @end example | |
5257 | ||
5258 | @noindent | |
5259 | might not have the effect you intended. In C, this means to add | |
5260 | @code{b} and @code{c} and place the result in @code{a}. The result | |
5261 | printed would be the value of @code{a}. In Modula-2, this means to compare | |
5262 | @code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value. | |
5263 | ||
4eb4cf57 | 5264 | @node Automatically |
18fae2a8 | 5265 | @subsection Having @value{GDBN} infer the source language |
c2bbbb22 | 5266 | |
18fae2a8 RP |
5267 | To have @value{GDBN} set the working language automatically, use @samp{set |
5268 | language local} or @samp{set language auto}. @value{GDBN} then infers the | |
c2bbbb22 RP |
5269 | language that a program was written in by looking at the name of its |
5270 | source files, and examining their extensions: | |
5271 | ||
5272 | @table @file | |
5273 | @item *.mod | |
5274 | Modula-2 source file | |
5275 | ||
5276 | @item *.c | |
5a2c1d85 RP |
5277 | C source file |
5278 | ||
5279 | @item *.C | |
c2bbbb22 | 5280 | @itemx *.cc |
5a2c1d85 | 5281 | C++ source file |
c2bbbb22 RP |
5282 | @end table |
5283 | ||
5284 | This information is recorded for each function or procedure in a source | |
5285 | file. When your program stops in a frame (usually by encountering a | |
18fae2a8 | 5286 | breakpoint), @value{GDBN} sets the working language to the language recorded |
c2bbbb22 RP |
5287 | for the function in that frame. If the language for a frame is unknown |
5288 | (that is, if the function or block corresponding to the frame was | |
5289 | defined in a source file that does not have a recognized extension), the | |
18fae2a8 | 5290 | current working language is not changed, and @value{GDBN} issues a warning. |
c2bbbb22 RP |
5291 | |
5292 | This may not seem necessary for most programs, which are written | |
5293 | entirely in one source language. However, program modules and libraries | |
5294 | written in one source language can be used by a main program written in | |
5295 | a different source language. Using @samp{set language auto} in this | |
5296 | case frees you from having to set the working language manually. | |
5297 | ||
4eb4cf57 | 5298 | @node Show |
c2bbbb22 RP |
5299 | @section Displaying the language |
5300 | ||
5301 | The following commands will help you find out which language is the | |
5302 | working language, and also what language source files were written in. | |
5303 | ||
5304 | @kindex show language | |
5305 | @kindex info frame | |
5306 | @kindex info source | |
5307 | @table @code | |
5308 | @item show language | |
5309 | Display the current working language. This is the | |
5310 | language you can use with commands such as @code{print} to | |
29a2b744 | 5311 | build and compute expressions that may involve variables in your program. |
c2bbbb22 RP |
5312 | |
5313 | @item info frame | |
1041a570 | 5314 | Among the other information listed here (@pxref{Frame Info, ,Information |
c2bbbb22 RP |
5315 | about a Frame}) is the source language for this frame. This is the |
5316 | language that will become the working language if you ever use an | |
5317 | identifier that is in this frame. | |
5318 | ||
5319 | @item info source | |
1041a570 | 5320 | Among the other information listed here (@pxref{Symbols, ,Examining the |
c2bbbb22 | 5321 | Symbol Table}) is the source language of this source file. |
c2bbbb22 RP |
5322 | @end table |
5323 | ||
4eb4cf57 | 5324 | @node Checks |
c2bbbb22 RP |
5325 | @section Type and range Checking |
5326 | ||
5327 | @quotation | |
18fae2a8 | 5328 | @emph{Warning:} In this release, the @value{GDBN} commands for type and range |
c2bbbb22 RP |
5329 | checking are included, but they do not yet have any effect. This |
5330 | section documents the intended facilities. | |
5331 | @end quotation | |
5332 | @c FIXME remove warning when type/range code added | |
5333 | ||
5334 | Some languages are designed to guard you against making seemingly common | |
5335 | errors through a series of compile- and run-time checks. These include | |
5336 | checking the type of arguments to functions and operators, and making | |
5337 | sure mathematical overflows are caught at run time. Checks such as | |
5338 | these help to ensure a program's correctness once it has been compiled | |
5339 | by eliminating type mismatches, and providing active checks for range | |
29a2b744 | 5340 | errors when your program is running. |
c2bbbb22 | 5341 | |
18fae2a8 RP |
5342 | @value{GDBN} can check for conditions like the above if you wish. |
5343 | Although @value{GDBN} will not check the statements in your program, it | |
5344 | can check expressions entered directly into @value{GDBN} for evaluation via | |
1041a570 | 5345 | the @code{print} command, for example. As with the working language, |
18fae2a8 | 5346 | @value{GDBN} can also decide whether or not to check automatically based on |
1041a570 RP |
5347 | your program's source language. @xref{Support, ,Supported Languages}, |
5348 | for the default settings of supported languages. | |
c2bbbb22 RP |
5349 | |
5350 | @menu | |
5351 | * Type Checking:: An overview of type checking | |
5352 | * Range Checking:: An overview of range checking | |
5353 | @end menu | |
5354 | ||
5355 | @cindex type checking | |
5356 | @cindex checks, type | |
4eb4cf57 | 5357 | @node Type Checking |
c2bbbb22 RP |
5358 | @subsection An overview of type checking |
5359 | ||
5360 | Some languages, such as Modula-2, are strongly typed, meaning that the | |
5361 | arguments to operators and functions have to be of the correct type, | |
5362 | otherwise an error occurs. These checks prevent type mismatch | |
5363 | errors from ever causing any run-time problems. For example, | |
5364 | ||
5365 | @example | |
5366 | 1 + 2 @result{} 3 | |
1041a570 | 5367 | @exdent but |
c2bbbb22 RP |
5368 | @error{} 1 + 2.3 |
5369 | @end example | |
5370 | ||
5371 | The second example fails because the @code{CARDINAL} 1 is not | |
5372 | type-compatible with the @code{REAL} 2.3. | |
5373 | ||
18fae2a8 | 5374 | For expressions you use in @value{GDBN} commands, you can tell the @value{GDBN} |
c2bbbb22 RP |
5375 | type checker to skip checking; to treat any mismatches as errors and |
5376 | abandon the expression; or only issue warnings when type mismatches | |
5377 | occur, but evaluate the expression anyway. When you choose the last of | |
18fae2a8 | 5378 | these, @value{GDBN} evaluates expressions like the second example above, but |
c2bbbb22 RP |
5379 | also issues a warning. |
5380 | ||
5381 | Even though you may turn type checking off, other type-based reasons may | |
18fae2a8 | 5382 | prevent @value{GDBN} from evaluating an expression. For instance, @value{GDBN} does not |
c2bbbb22 RP |
5383 | know how to add an @code{int} and a @code{struct foo}. These particular |
5384 | type errors have nothing to do with the language in use, and usually | |
5385 | arise from expressions, such as the one described above, which make | |
5386 | little sense to evaluate anyway. | |
5387 | ||
5388 | Each language defines to what degree it is strict about type. For | |
5389 | instance, both Modula-2 and C require the arguments to arithmetical | |
5390 | operators to be numbers. In C, enumerated types and pointers can be | |
5391 | represented as numbers, so that they are valid arguments to mathematical | |
1041a570 | 5392 | operators. @xref{Support, ,Supported Languages}, for further |
c2bbbb22 RP |
5393 | details on specific languages. |
5394 | ||
18fae2a8 | 5395 | @value{GDBN} provides some additional commands for controlling the type checker: |
c2bbbb22 RP |
5396 | |
5397 | @kindex set check | |
5398 | @kindex set check type | |
5399 | @kindex show check type | |
5400 | @table @code | |
5401 | @item set check type auto | |
e251e767 | 5402 | Set type checking on or off based on the current working language. |
1041a570 | 5403 | @xref{Support, ,Supported Languages}, for the default settings for |
c2bbbb22 RP |
5404 | each language. |
5405 | ||
5406 | @item set check type on | |
5407 | @itemx set check type off | |
5408 | Set type checking on or off, overriding the default setting for the | |
5409 | current working language. Issue a warning if the setting does not | |
5410 | match the language's default. If any type mismatches occur in | |
18fae2a8 | 5411 | evaluating an expression while typechecking is on, @value{GDBN} prints a |
c2bbbb22 RP |
5412 | message and aborts evaluation of the expression. |
5413 | ||
5414 | @item set check type warn | |
5415 | Cause the type checker to issue warnings, but to always attempt to | |
5416 | evaluate the expression. Evaluating the expression may still | |
18fae2a8 | 5417 | be impossible for other reasons. For example, @value{GDBN} cannot add |
c2bbbb22 RP |
5418 | numbers and structures. |
5419 | ||
5420 | @item show type | |
18fae2a8 | 5421 | Show the current setting of the type checker, and whether or not @value{GDBN} is |
c2bbbb22 RP |
5422 | setting it automatically. |
5423 | @end table | |
5424 | ||
5425 | @cindex range checking | |
5426 | @cindex checks, range | |
4eb4cf57 | 5427 | @node Range Checking |
ed447b95 | 5428 | @subsection An overview of range checking |
c2bbbb22 RP |
5429 | |
5430 | In some languages (such as Modula-2), it is an error to exceed the | |
5431 | bounds of a type; this is enforced with run-time checks. Such range | |
5432 | checking is meant to ensure program correctness by making sure | |
5433 | computations do not overflow, or indices on an array element access do | |
5434 | not exceed the bounds of the array. | |
5435 | ||
ed447b95 RP |
5436 | For expressions you use in @value{GDBN} commands, you can tell |
5437 | @value{GDBN} to treat range errors in one of three ways: ignore them, | |
5438 | always treat them as errors and abandon the expression, or issue | |
5439 | warnings but evaluate the expression anyway. | |
c2bbbb22 RP |
5440 | |
5441 | A range error can result from numerical overflow, from exceeding an | |
ed447b95 | 5442 | array index bound, or when you type a constant that is not a member |
c2bbbb22 RP |
5443 | of any type. Some languages, however, do not treat overflows as an |
5444 | error. In many implementations of C, mathematical overflow causes the | |
5445 | result to ``wrap around'' to lower values---for example, if @var{m} is | |
5446 | the largest integer value, and @var{s} is the smallest, then | |
1041a570 | 5447 | |
c2bbbb22 RP |
5448 | @example |
5449 | @var{m} + 1 @result{} @var{s} | |
5450 | @end example | |
5451 | ||
5452 | This, too, is specific to individual languages, and in some cases | |
1041a570 | 5453 | specific to individual compilers or machines. @xref{Support, , |
c2bbbb22 RP |
5454 | Supported Languages}, for further details on specific languages. |
5455 | ||
18fae2a8 | 5456 | @value{GDBN} provides some additional commands for controlling the range checker: |
c2bbbb22 RP |
5457 | |
5458 | @kindex set check | |
5459 | @kindex set check range | |
5460 | @kindex show check range | |
5461 | @table @code | |
5462 | @item set check range auto | |
e251e767 | 5463 | Set range checking on or off based on the current working language. |
1041a570 | 5464 | @xref{Support, ,Supported Languages}, for the default settings for |
c2bbbb22 RP |
5465 | each language. |
5466 | ||
5467 | @item set check range on | |
5468 | @itemx set check range off | |
5469 | Set range checking on or off, overriding the default setting for the | |
5470 | current working language. A warning is issued if the setting does not | |
5471 | match the language's default. If a range error occurs, then a message | |
5472 | is printed and evaluation of the expression is aborted. | |
5473 | ||
5474 | @item set check range warn | |
18fae2a8 | 5475 | Output messages when the @value{GDBN} range checker detects a range error, |
c2bbbb22 RP |
5476 | but attempt to evaluate the expression anyway. Evaluating the |
5477 | expression may still be impossible for other reasons, such as accessing | |
5478 | memory that the process does not own (a typical example from many UNIX | |
5479 | systems). | |
5480 | ||
5481 | @item show range | |
e251e767 | 5482 | Show the current setting of the range checker, and whether or not it is |
18fae2a8 | 5483 | being set automatically by @value{GDBN}. |
c2bbbb22 RP |
5484 | @end table |
5485 | ||
4eb4cf57 | 5486 | @node Support |
c2bbbb22 RP |
5487 | @section Supported Languages |
5488 | ||
18fae2a8 | 5489 | @value{GDBN} 4 supports C, C++, and Modula-2. Some @value{GDBN} |
1041a570 | 5490 | features may be used in expressions regardless of the language you |
18fae2a8 | 5491 | use: the @value{GDBN} @code{@@} and @code{::} operators, and the |
1041a570 RP |
5492 | @samp{@{type@}addr} construct (@pxref{Expressions, ,Expressions}) can be |
5493 | used with the constructs of any of the supported languages. | |
c2bbbb22 RP |
5494 | |
5495 | The following sections detail to what degree each of these | |
18fae2a8 | 5496 | source languages is supported by @value{GDBN}. These sections are |
c2bbbb22 | 5497 | not meant to be language tutorials or references, but serve only as a |
18fae2a8 | 5498 | reference guide to what the @value{GDBN} expression parser will accept, and |
c2bbbb22 RP |
5499 | what input and output formats should look like for different languages. |
5500 | There are many good books written on each of these languages; please | |
5501 | look to these for a language reference or tutorial. | |
5502 | ||
5503 | @menu | |
5504 | * C:: C and C++ | |
5505 | * Modula-2:: Modula-2 | |
5506 | @end menu | |
5507 | ||
4eb4cf57 | 5508 | @node C |
c2bbbb22 RP |
5509 | @subsection C and C++ |
5510 | @cindex C and C++ | |
c2bbbb22 | 5511 | @cindex expressions in C or C++ |
0f153e74 | 5512 | |
18fae2a8 | 5513 | Since C and C++ are so closely related, many features of @value{GDBN} apply |
5a2c1d85 RP |
5514 | to both languages. Whenever this is the case, we discuss both languages |
5515 | together. | |
b80282d5 RP |
5516 | |
5517 | @cindex C++ | |
5518 | @kindex g++ | |
5519 | @cindex GNU C++ | |
c2bbbb22 | 5520 | The C++ debugging facilities are jointly implemented by the GNU C++ |
18fae2a8 | 5521 | compiler and @value{GDBN}. Therefore, to debug your C++ code effectively, |
c2bbbb22 RP |
5522 | you must compile your C++ programs with the GNU C++ compiler, |
5523 | @code{g++}. | |
18fae2a8 RP |
5524 | @end ifclear |
5525 | @ifset CONLY | |
0f153e74 RP |
5526 | @node C |
5527 | @chapter C Language Support | |
5528 | @cindex C language | |
5529 | @cindex expressions in C | |
5530 | ||
18fae2a8 RP |
5531 | Information specific to the C language is built into @value{GDBN} so that you |
5532 | can use C expressions while degugging. This also permits @value{GDBN} to | |
0f153e74 | 5533 | output values in a manner consistent with C conventions. |
c2bbbb22 | 5534 | |
0f153e74 | 5535 | @menu |
ed447b95 RP |
5536 | * C Operators:: C operators |
5537 | * C Constants:: C constants | |
18fae2a8 | 5538 | * Debugging C:: @value{GDBN} and C |
0f153e74 | 5539 | @end menu |
18fae2a8 RP |
5540 | @end ifset |
5541 | @ifclear CONLY | |
b80282d5 | 5542 | @menu |
ed447b95 RP |
5543 | * C Operators:: C and C++ operators |
5544 | * C Constants:: C and C++ constants | |
5545 | * Cplus expressions:: C++ expressions | |
c2bbbb22 | 5546 | * C Defaults:: Default settings for C and C++ |
ed447b95 | 5547 | * C Checks:: C and C++ type and range checks |
18fae2a8 | 5548 | * Debugging C:: @value{GDBN} and C |
c2bbbb22 | 5549 | * Debugging C plus plus:: Special features for C++ |
b80282d5 | 5550 | @end menu |
18fae2a8 | 5551 | @end ifclear |
b80282d5 | 5552 | |
18fae2a8 | 5553 | @ifclear CONLY |
c2bbbb22 | 5554 | @cindex C and C++ operators |
4eb4cf57 | 5555 | @node C Operators |
c2bbbb22 | 5556 | @subsubsection C and C++ Operators |
18fae2a8 RP |
5557 | @end ifclear |
5558 | @ifset CONLY | |
0f153e74 RP |
5559 | @cindex C operators |
5560 | @node C Operators | |
5561 | @section C Operators | |
18fae2a8 | 5562 | @end ifset |
c2bbbb22 RP |
5563 | |
5564 | Operators must be defined on values of specific types. For instance, | |
5565 | @code{+} is defined on numbers, but not on structures. Operators are | |
0f153e74 RP |
5566 | often defined on groups of types. |
5567 | ||
18fae2a8 | 5568 | @ifclear CONLY |
0f153e74 | 5569 | For the purposes of C and C++, the following definitions hold: |
18fae2a8 | 5570 | @end ifclear |
c2bbbb22 RP |
5571 | |
5572 | @itemize @bullet | |
e251e767 | 5573 | @item |
c2bbbb22 RP |
5574 | @emph{Integral types} include @code{int} with any of its storage-class |
5575 | specifiers, @code{char}, and @code{enum}s. | |
5576 | ||
5577 | @item | |
5578 | @emph{Floating-point types} include @code{float} and @code{double}. | |
5579 | ||
5580 | @item | |
5581 | @emph{Pointer types} include all types defined as @code{(@var{type} | |
5582 | *)}. | |
5583 | ||
e251e767 | 5584 | @item |
c2bbbb22 | 5585 | @emph{Scalar types} include all of the above. |
c2bbbb22 RP |
5586 | @end itemize |
5587 | ||
5588 | @noindent | |
5589 | The following operators are supported. They are listed here | |
5590 | in order of increasing precedence: | |
5591 | ||
5592 | @table @code | |
18fae2a8 | 5593 | @item , |
c2bbbb22 RP |
5594 | The comma or sequencing operator. Expressions in a comma-separated list |
5595 | are evaluated from left to right, with the result of the entire | |
5596 | expression being the last expression evaluated. | |
5597 | ||
5598 | @item = | |
5599 | Assignment. The value of an assignment expression is the value | |
5600 | assigned. Defined on scalar types. | |
5601 | ||
5602 | @item @var{op}= | |
1041a570 RP |
5603 | Used in an expression of the form @w{@code{@var{a} @var{op}= @var{b}}}, |
5604 | and translated to @w{@code{@var{a} = @var{a op b}}}. | |
5605 | @w{@code{@var{op}=}} and @code{=} have the same precendence. | |
5606 | @var{op} is any one of the operators @code{|}, @code{^}, @code{&}, | |
5607 | @code{<<}, @code{>>}, @code{+}, @code{-}, @code{*}, @code{/}, @code{%}. | |
c2bbbb22 RP |
5608 | |
5609 | @item ?: | |
5610 | The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought | |
5611 | of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an | |
5612 | integral type. | |
5613 | ||
5614 | @item || | |
1041a570 | 5615 | Logical @sc{or}. Defined on integral types. |
c2bbbb22 RP |
5616 | |
5617 | @item && | |
1041a570 | 5618 | Logical @sc{and}. Defined on integral types. |
c2bbbb22 RP |
5619 | |
5620 | @item | | |
1041a570 | 5621 | Bitwise @sc{or}. Defined on integral types. |
c2bbbb22 RP |
5622 | |
5623 | @item ^ | |
1041a570 | 5624 | Bitwise exclusive-@sc{or}. Defined on integral types. |
c2bbbb22 RP |
5625 | |
5626 | @item & | |
1041a570 | 5627 | Bitwise @sc{and}. Defined on integral types. |
c2bbbb22 RP |
5628 | |
5629 | @item ==@r{, }!= | |
5630 | Equality and inequality. Defined on scalar types. The value of these | |
5631 | expressions is 0 for false and non-zero for true. | |
5632 | ||
5633 | @item <@r{, }>@r{, }<=@r{, }>= | |
5634 | Less than, greater than, less than or equal, greater than or equal. | |
5635 | Defined on scalar types. The value of these expressions is 0 for false | |
5636 | and non-zero for true. | |
5637 | ||
5638 | @item <<@r{, }>> | |
18fae2a8 | 5639 | left shift, and right shift. Defined on integral types. |
c2bbbb22 | 5640 | |
e251e767 | 5641 | @item @@ |
18fae2a8 | 5642 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). |
c2bbbb22 RP |
5643 | |
5644 | @item +@r{, }- | |
5645 | Addition and subtraction. Defined on integral types, floating-point types and | |
e251e767 | 5646 | pointer types. |
c2bbbb22 RP |
5647 | |
5648 | @item *@r{, }/@r{, }% | |
5649 | Multiplication, division, and modulus. Multiplication and division are | |
5650 | defined on integral and floating-point types. Modulus is defined on | |
5651 | integral types. | |
5652 | ||
5653 | @item ++@r{, }-- | |
5654 | Increment and decrement. When appearing before a variable, the | |
5655 | operation is performed before the variable is used in an expression; | |
5656 | when appearing after it, the variable's value is used before the | |
5657 | operation takes place. | |
5658 | ||
5659 | @item * | |
5660 | Pointer dereferencing. Defined on pointer types. Same precedence as | |
5661 | @code{++}. | |
5662 | ||
5663 | @item & | |
5664 | Address operator. Defined on variables. Same precedence as @code{++}. | |
5665 | ||
18fae2a8 RP |
5666 | @ifclear CONLY |
5667 | For debugging C++, @value{GDBN} implements a use of @samp{&} beyond what's | |
6ca72cc6 RP |
5668 | allowed in the C++ language itself: you can use @samp{&(&@var{ref})} |
5669 | (or, if you prefer, simply @samp{&&@var{ref}} to examine the address | |
5670 | where a C++ reference variable (declared with @samp{&@var{ref}}) is | |
5671 | stored. | |
18fae2a8 | 5672 | @end ifclear |
6ca72cc6 | 5673 | |
c2bbbb22 RP |
5674 | @item - |
5675 | Negative. Defined on integral and floating-point types. Same | |
5676 | precedence as @code{++}. | |
5677 | ||
5678 | @item ! | |
5679 | Logical negation. Defined on integral types. Same precedence as | |
5680 | @code{++}. | |
5681 | ||
5682 | @item ~ | |
5683 | Bitwise complement operator. Defined on integral types. Same precedence as | |
5684 | @code{++}. | |
5685 | ||
18fae2a8 | 5686 | |
c2bbbb22 RP |
5687 | @item .@r{, }-> |
5688 | Structure member, and pointer-to-structure member. For convenience, | |
18fae2a8 | 5689 | @value{GDBN} regards the two as equivalent, choosing whether to dereference a |
e251e767 | 5690 | pointer based on the stored type information. |
c2bbbb22 RP |
5691 | Defined on @code{struct}s and @code{union}s. |
5692 | ||
5693 | @item [] | |
5694 | Array indexing. @code{@var{a}[@var{i}]} is defined as | |
5695 | @code{*(@var{a}+@var{i})}. Same precedence as @code{->}. | |
5696 | ||
5697 | @item () | |
18fae2a8 | 5698 | Function parameter list. Same precedence as @code{->}. |
c2bbbb22 | 5699 | |
18fae2a8 | 5700 | @ifclear CONLY |
c2bbbb22 RP |
5701 | @item :: |
5702 | C++ scope resolution operator. Defined on | |
5703 | @code{struct}, @code{union}, and @code{class} types. | |
18fae2a8 | 5704 | @end ifclear |
c2bbbb22 RP |
5705 | |
5706 | @item :: | |
ed447b95 RP |
5707 | Doubled colons |
5708 | @ifclear CONLY | |
5709 | also | |
5710 | @end ifclear | |
5711 | represent the @value{GDBN} scope operator (@pxref{Expressions, | |
5712 | ,Expressions}). | |
18fae2a8 | 5713 | @ifclear CONLY |
0f153e74 | 5714 | Same precedence as @code{::}, above. |
18fae2a8 | 5715 | @end ifclear |
c2bbbb22 RP |
5716 | @end table |
5717 | ||
18fae2a8 | 5718 | @ifclear CONLY |
c2bbbb22 | 5719 | @cindex C and C++ constants |
4eb4cf57 | 5720 | @node C Constants |
c2bbbb22 | 5721 | @subsubsection C and C++ Constants |
0f153e74 | 5722 | |
18fae2a8 | 5723 | @value{GDBN} allows you to express the constants of C and C++ in the |
0f153e74 | 5724 | following ways: |
18fae2a8 RP |
5725 | @end ifclear |
5726 | @ifset CONLY | |
0f153e74 RP |
5727 | @cindex C constants |
5728 | @node C Constants | |
5729 | @section C Constants | |
c2bbbb22 | 5730 | |
18fae2a8 | 5731 | @value{GDBN} allows you to express the constants of C in the |
c2bbbb22 | 5732 | following ways: |
18fae2a8 | 5733 | @end ifset |
c2bbbb22 RP |
5734 | |
5735 | @itemize @bullet | |
c2bbbb22 RP |
5736 | @item |
5737 | Integer constants are a sequence of digits. Octal constants are | |
5738 | specified by a leading @samp{0} (ie. zero), and hexadecimal constants by | |
1041a570 | 5739 | a leading @samp{0x} or @samp{0X}. Constants may also end with a letter |
c2bbbb22 RP |
5740 | @samp{l}, specifying that the constant should be treated as a |
5741 | @code{long} value. | |
5742 | ||
5743 | @item | |
5744 | Floating point constants are a sequence of digits, followed by a decimal | |
5745 | point, followed by a sequence of digits, and optionally followed by an | |
5746 | exponent. An exponent is of the form: | |
5747 | @samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another | |
5748 | sequence of digits. The @samp{+} is optional for positive exponents. | |
5749 | ||
5750 | @item | |
5751 | Enumerated constants consist of enumerated identifiers, or their | |
5752 | integral equivalents. | |
5753 | ||
5754 | @item | |
5755 | Character constants are a single character surrounded by single quotes | |
5756 | (@code{'}), or a number---the ordinal value of the corresponding character | |
5757 | (usually its @sc{ASCII} value). Within quotes, the single character may | |
5758 | be represented by a letter or by @dfn{escape sequences}, which are of | |
5759 | the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation | |
5760 | of the character's ordinal value; or of the form @samp{\@var{x}}, where | |
5761 | @samp{@var{x}} is a predefined special character---for example, | |
5762 | @samp{\n} for newline. | |
5763 | ||
5764 | @item | |
5765 | String constants are a sequence of character constants surrounded | |
5766 | by double quotes (@code{"}). | |
5767 | ||
5768 | @item | |
5769 | Pointer constants are an integral value. | |
c2bbbb22 RP |
5770 | @end itemize |
5771 | ||
18fae2a8 | 5772 | @ifclear CONLY |
ed447b95 | 5773 | @node Cplus expressions |
c2bbbb22 | 5774 | @subsubsection C++ Expressions |
b80282d5 RP |
5775 | |
5776 | @cindex expressions in C++ | |
18fae2a8 | 5777 | @value{GDBN}'s expression handling has a number of extensions to |
b1385986 RP |
5778 | interpret a significant subset of C++ expressions. |
5779 | ||
5780 | @cindex C++ support, not in @sc{coff} | |
5781 | @cindex @sc{coff} versus C++ | |
5782 | @cindex C++ and object formats | |
5783 | @cindex object formats and C++ | |
5784 | @cindex a.out and C++ | |
5785 | @cindex @sc{ecoff} and C++ | |
5786 | @cindex @sc{xcoff} and C++ | |
5787 | @cindex @sc{elf}/stabs and C++ | |
5788 | @cindex @sc{elf}/@sc{dwarf} and C++ | |
5789 | @quotation | |
5790 | @emph{Warning:} Most of these extensions depend on the use of additional | |
5791 | debugging information in the symbol table, and thus require a rich, | |
5792 | extendable object code format. In particular, if your system uses | |
5793 | a.out, MIPS @sc{ecoff}, RS/6000 @sc{xcoff}, or Sun @sc{elf} with stabs | |
5794 | extensions to the symbol table, these facilities are all available. | |
5795 | Where the object code format is standard @sc{coff}, on the other hand, | |
18fae2a8 | 5796 | most of the C++ support in @value{GDBN} will @emph{not} work, nor can it. |
b1385986 | 5797 | For the standard SVr4 debugging format, @sc{dwarf} in @sc{elf}, the |
18fae2a8 | 5798 | standard is still evolving, so the C++ support in @value{GDBN} is still |
b1385986 RP |
5799 | fragile; when this debugging format stabilizes, however, C++ support |
5800 | will also be available on systems that use it. | |
5801 | @end quotation | |
b80282d5 RP |
5802 | |
5803 | @enumerate | |
5804 | ||
5805 | @cindex member functions | |
e251e767 | 5806 | @item |
b80282d5 | 5807 | Member function calls are allowed; you can use expressions like |
1041a570 | 5808 | |
b80282d5 RP |
5809 | @example |
5810 | count = aml->GetOriginal(x, y) | |
5811 | @end example | |
5812 | ||
5813 | @kindex this | |
5814 | @cindex namespace in C++ | |
e251e767 | 5815 | @item |
b80282d5 RP |
5816 | While a member function is active (in the selected stack frame), your |
5817 | expressions have the same namespace available as the member function; | |
18fae2a8 | 5818 | that is, @value{GDBN} allows implicit references to the class instance |
b80282d5 RP |
5819 | pointer @code{this} following the same rules as C++. |
5820 | ||
5821 | @cindex call overloaded functions | |
5822 | @cindex type conversions in C++ | |
e251e767 | 5823 | @item |
18fae2a8 | 5824 | You can call overloaded functions; @value{GDBN} will resolve the function |
b80282d5 RP |
5825 | call to the right definition, with one restriction---you must use |
5826 | arguments of the type required by the function that you want to call. | |
18fae2a8 | 5827 | @value{GDBN} will not perform conversions requiring constructors or |
b80282d5 RP |
5828 | user-defined type operators. |
5829 | ||
5830 | @cindex reference declarations | |
5831 | @item | |
18fae2a8 | 5832 | @value{GDBN} understands variables declared as C++ references; you can use them in |
b80282d5 | 5833 | expressions just as you do in C++ source---they are automatically |
e251e767 | 5834 | dereferenced. |
b80282d5 | 5835 | |
18fae2a8 | 5836 | In the parameter list shown when @value{GDBN} displays a frame, the values of |
b80282d5 RP |
5837 | reference variables are not displayed (unlike other variables); this |
5838 | avoids clutter, since references are often used for large structures. | |
5839 | The @emph{address} of a reference variable is always shown, unless | |
1041a570 | 5840 | you have specified @samp{set print address off}. |
b80282d5 RP |
5841 | |
5842 | @item | |
18fae2a8 | 5843 | @value{GDBN} supports the C++ name resolution operator @code{::}---your |
c2bbbb22 RP |
5844 | expressions can use it just as expressions in your program do. Since |
5845 | one scope may be defined in another, you can use @code{::} repeatedly if | |
5846 | necessary, for example in an expression like | |
18fae2a8 | 5847 | @samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows |
c2bbbb22 | 5848 | resolving name scope by reference to source files, in both C and C++ |
1041a570 | 5849 | debugging (@pxref{Variables, ,Program Variables}). |
b80282d5 RP |
5850 | @end enumerate |
5851 | ||
4eb4cf57 | 5852 | @node C Defaults |
c2bbbb22 RP |
5853 | @subsubsection C and C++ Defaults |
5854 | @cindex C and C++ defaults | |
5855 | ||
18fae2a8 | 5856 | If you allow @value{GDBN} to set type and range checking automatically, they |
e251e767 | 5857 | both default to @code{off} whenever the working language changes to |
18fae2a8 | 5858 | C or C++. This happens regardless of whether you, or @value{GDBN}, |
c2bbbb22 RP |
5859 | selected the working language. |
5860 | ||
18fae2a8 | 5861 | If you allow @value{GDBN} to set the language automatically, it sets the |
5a2c1d85 RP |
5862 | working language to C or C++ on entering code compiled from a source file |
5863 | whose name ends with @file{.c}, @file{.C}, or @file{.cc}. | |
18fae2a8 | 5864 | @xref{Automatically, ,Having @value{GDBN} infer the source language}, for |
c2bbbb22 RP |
5865 | further details. |
5866 | ||
4eb4cf57 | 5867 | @node C Checks |
c2bbbb22 RP |
5868 | @subsubsection C and C++ Type and Range Checks |
5869 | @cindex C and C++ checks | |
5870 | ||
18fae2a8 RP |
5871 | By default, when @value{GDBN} parses C or C++ expressions, type checking |
5872 | is not used. However, if you turn type checking on, @value{GDBN} will | |
c2bbbb22 RP |
5873 | consider two variables type equivalent if: |
5874 | ||
5875 | @itemize @bullet | |
5876 | @item | |
5877 | The two variables are structured and have the same structure, union, or | |
5878 | enumerated tag. | |
5879 | ||
e251e767 | 5880 | @item |
c2bbbb22 RP |
5881 | Two two variables have the same type name, or types that have been |
5882 | declared equivalent through @code{typedef}. | |
5883 | ||
5884 | @ignore | |
5885 | @c leaving this out because neither J Gilmore nor R Pesch understand it. | |
5886 | @c FIXME--beers? | |
5887 | @item | |
5888 | The two @code{struct}, @code{union}, or @code{enum} variables are | |
5889 | declared in the same declaration. (Note: this may not be true for all C | |
5890 | compilers.) | |
5891 | @end ignore | |
c2bbbb22 RP |
5892 | @end itemize |
5893 | ||
5894 | Range checking, if turned on, is done on mathematical operations. Array | |
5895 | indices are not checked, since they are often used to index a pointer | |
5896 | that is not itself an array. | |
18fae2a8 | 5897 | @end ifclear |
c2bbbb22 | 5898 | |
18fae2a8 | 5899 | @ifclear CONLY |
4eb4cf57 | 5900 | @node Debugging C |
18fae2a8 RP |
5901 | @subsubsection @value{GDBN} and C |
5902 | @end ifclear | |
5903 | @ifset CONLY | |
5904 | @node Debugging C | |
5905 | @section @value{GDBN} and C | |
5906 | @end ifset | |
c2bbbb22 RP |
5907 | |
5908 | The @code{set print union} and @code{show print union} commands apply to | |
5909 | the @code{union} type. When set to @samp{on}, any @code{union} that is | |
5910 | inside a @code{struct} or @code{class} will also be printed. | |
5911 | Otherwise, it will appear as @samp{@{...@}}. | |
5912 | ||
5913 | The @code{@@} operator aids in the debugging of dynamic arrays, formed | |
ed447b95 RP |
5914 | with pointers and a memory allocation function. @xref{Expressions, |
5915 | ,Expressions}. | |
c2bbbb22 | 5916 | |
18fae2a8 | 5917 | @ifclear CONLY |
4eb4cf57 | 5918 | @node Debugging C plus plus |
18fae2a8 | 5919 | @subsubsection @value{GDBN} Features for C++ |
b80282d5 RP |
5920 | |
5921 | @cindex commands for C++ | |
18fae2a8 | 5922 | Some @value{GDBN} commands are particularly useful with C++, and some are |
b80282d5 RP |
5923 | designed specifically for use with C++. Here is a summary: |
5924 | ||
5925 | @table @code | |
5926 | @cindex break in overloaded functions | |
5927 | @item @r{breakpoint menus} | |
5928 | When you want a breakpoint in a function whose name is overloaded, | |
18fae2a8 | 5929 | @value{GDBN}'s breakpoint menus help you specify which function definition |
b80282d5 RP |
5930 | you want. @xref{Breakpoint Menus}. |
5931 | ||
5932 | @cindex overloading in C++ | |
5933 | @item rbreak @var{regex} | |
5934 | Setting breakpoints using regular expressions is helpful for setting | |
5935 | breakpoints on overloaded functions that are not members of any special | |
e251e767 | 5936 | classes. |
29a2b744 | 5937 | @xref{Set Breaks, ,Setting Breakpoints}. |
b80282d5 RP |
5938 | |
5939 | @cindex C++ exception handling | |
5940 | @item catch @var{exceptions} | |
5941 | @itemx info catch | |
29a2b744 | 5942 | Debug C++ exception handling using these commands. @xref{Exception |
1041a570 | 5943 | Handling, ,Breakpoints and Exceptions}. |
b80282d5 | 5944 | |
e251e767 | 5945 | @cindex inheritance |
b80282d5 RP |
5946 | @item ptype @var{typename} |
5947 | Print inheritance relationships as well as other information for type | |
e251e767 | 5948 | @var{typename}. |
1041a570 | 5949 | @xref{Symbols, ,Examining the Symbol Table}. |
b80282d5 RP |
5950 | |
5951 | @cindex C++ symbol display | |
5952 | @item set print demangle | |
5953 | @itemx show print demangle | |
5954 | @itemx set print asm-demangle | |
5955 | @itemx show print asm-demangle | |
5956 | Control whether C++ symbols display in their source form, both when | |
5957 | displaying code as C++ source and when displaying disassemblies. | |
1041a570 | 5958 | @xref{Print Settings, ,Print Settings}. |
b80282d5 RP |
5959 | |
5960 | @item set print object | |
5961 | @itemx show print object | |
e251e767 | 5962 | Choose whether to print derived (actual) or declared types of objects. |
1041a570 | 5963 | @xref{Print Settings, ,Print Settings}. |
b80282d5 RP |
5964 | |
5965 | @item set print vtbl | |
5966 | @itemx show print vtbl | |
5967 | Control the format for printing virtual function tables. | |
1041a570 | 5968 | @xref{Print Settings, ,Print Settings}. |
6f3ec223 RP |
5969 | |
5970 | @item @r{Overloaded symbol names} | |
5971 | You can specify a particular definition of an overloaded symbol, using | |
5972 | the same notation that's used to declare such symbols in C++: type | |
5973 | @code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can | |
18fae2a8 | 5974 | also use @value{GDBN}'s command-line word completion facilities to list the |
6f3ec223 RP |
5975 | available choices, or to finish the type list for you. |
5976 | @xref{Completion,, Command Completion}, for details on how to do this. | |
b80282d5 RP |
5977 | @end table |
5978 | ||
4eb4cf57 | 5979 | @node Modula-2 |
c2bbbb22 RP |
5980 | @subsection Modula-2 |
5981 | @cindex Modula-2 | |
5982 | ||
ed447b95 RP |
5983 | The extensions made to @value{GDBN} to support Modula-2 only support |
5984 | output from the GNU Modula-2 compiler (which is currently being | |
5985 | developed). Other Modula-2 compilers are not currently supported, and | |
5986 | attempting to debug executables produced by them will most likely | |
5987 | result in an error as @value{GDBN} reads in the executable's symbol | |
5988 | table. | |
c2bbbb22 RP |
5989 | |
5990 | @cindex expressions in Modula-2 | |
5991 | @menu | |
5992 | * M2 Operators:: Built-in operators | |
ed447b95 RP |
5993 | * Built-In Func/Proc:: Built-in functions and procedures |
5994 | * M2 Constants:: Modula-2 constants | |
c2bbbb22 RP |
5995 | * M2 Defaults:: Default settings for Modula-2 |
5996 | * Deviations:: Deviations from standard Modula-2 | |
ed447b95 | 5997 | * M2 Checks:: Modula-2 type and range checks |
c2bbbb22 | 5998 | * M2 Scope:: The scope operators @code{::} and @code{.} |
18fae2a8 | 5999 | * GDB/M2:: @value{GDBN} and Modula-2 |
c2bbbb22 RP |
6000 | @end menu |
6001 | ||
4eb4cf57 | 6002 | @node M2 Operators |
c2bbbb22 RP |
6003 | @subsubsection Operators |
6004 | @cindex Modula-2 operators | |
6005 | ||
6006 | Operators must be defined on values of specific types. For instance, | |
6007 | @code{+} is defined on numbers, but not on structures. Operators are | |
6008 | often defined on groups of types. For the purposes of Modula-2, the | |
6009 | following definitions hold: | |
6010 | ||
6011 | @itemize @bullet | |
6012 | ||
6013 | @item | |
6014 | @emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and | |
6015 | their subranges. | |
6016 | ||
6017 | @item | |
6018 | @emph{Character types} consist of @code{CHAR} and its subranges. | |
6019 | ||
6020 | @item | |
6021 | @emph{Floating-point types} consist of @code{REAL}. | |
6022 | ||
6023 | @item | |
6024 | @emph{Pointer types} consist of anything declared as @code{POINTER TO | |
6025 | @var{type}}. | |
6026 | ||
6027 | @item | |
6028 | @emph{Scalar types} consist of all of the above. | |
6029 | ||
6030 | @item | |
6031 | @emph{Set types} consist of @code{SET}s and @code{BITSET}s. | |
6032 | ||
6033 | @item | |
6034 | @emph{Boolean types} consist of @code{BOOLEAN}. | |
c2bbbb22 RP |
6035 | @end itemize |
6036 | ||
6037 | @noindent | |
6038 | The following operators are supported, and appear in order of | |
6039 | increasing precedence: | |
6040 | ||
6041 | @table @code | |
c2bbbb22 RP |
6042 | @item , |
6043 | Function argument or array index separator. | |
18fae2a8 | 6044 | |
c2bbbb22 RP |
6045 | @item := |
6046 | Assignment. The value of @var{var} @code{:=} @var{value} is | |
6047 | @var{value}. | |
6048 | ||
6049 | @item <@r{, }> | |
6050 | Less than, greater than on integral, floating-point, or enumerated | |
6051 | types. | |
6052 | ||
6053 | @item <=@r{, }>= | |
6054 | Less than, greater than, less than or equal to, greater than or equal to | |
6055 | on integral, floating-point and enumerated types, or set inclusion on | |
6056 | set types. Same precedence as @code{<}. | |
6057 | ||
6058 | @item =@r{, }<>@r{, }# | |
6059 | Equality and two ways of expressing inequality, valid on scalar types. | |
18fae2a8 | 6060 | Same precedence as @code{<}. In @value{GDBN} scripts, only @code{<>} is |
c2bbbb22 RP |
6061 | available for inequality, since @code{#} conflicts with the script |
6062 | comment character. | |
6063 | ||
6064 | @item IN | |
6065 | Set membership. Defined on set types and the types of their members. | |
6066 | Same precedence as @code{<}. | |
6067 | ||
6068 | @item OR | |
6069 | Boolean disjunction. Defined on boolean types. | |
6070 | ||
6071 | @item AND@r{, }& | |
6072 | Boolean conjuction. Defined on boolean types. | |
6073 | ||
6074 | @item @@ | |
18fae2a8 | 6075 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). |
c2bbbb22 RP |
6076 | |
6077 | @item +@r{, }- | |
6078 | Addition and subtraction on integral and floating-point types, or union | |
6079 | and difference on set types. | |
6080 | ||
6081 | @item * | |
6082 | Multiplication on integral and floating-point types, or set intersection | |
6083 | on set types. | |
6084 | ||
6085 | @item / | |
6086 | Division on floating-point types, or symmetric set difference on set | |
6087 | types. Same precedence as @code{*}. | |
6088 | ||
6089 | @item DIV@r{, }MOD | |
6090 | Integer division and remainder. Defined on integral types. Same | |
6091 | precedence as @code{*}. | |
6092 | ||
6093 | @item - | |
6094 | Negative. Defined on @code{INTEGER}s and @code{REAL}s. | |
6095 | ||
6096 | @item ^ | |
e251e767 | 6097 | Pointer dereferencing. Defined on pointer types. |
c2bbbb22 RP |
6098 | |
6099 | @item NOT | |
6100 | Boolean negation. Defined on boolean types. Same precedence as | |
6101 | @code{^}. | |
6102 | ||
6103 | @item . | |
6104 | @code{RECORD} field selector. Defined on @code{RECORD}s. Same | |
6105 | precedence as @code{^}. | |
6106 | ||
6107 | @item [] | |
6108 | Array indexing. Defined on @code{ARRAY}s. Same precedence as @code{^}. | |
6109 | ||
6110 | @item () | |
6111 | Procedure argument list. Defined on @code{PROCEDURE}s. Same precedence | |
6112 | as @code{^}. | |
6113 | ||
6114 | @item ::@r{, }. | |
18fae2a8 | 6115 | @value{GDBN} and Modula-2 scope operators. |
c2bbbb22 RP |
6116 | @end table |
6117 | ||
6118 | @quotation | |
18fae2a8 | 6119 | @emph{Warning:} Sets and their operations are not yet supported, so @value{GDBN} |
c2bbbb22 RP |
6120 | will treat the use of the operator @code{IN}, or the use of operators |
6121 | @code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#}, | |
6122 | @code{<=}, and @code{>=} on sets as an error. | |
6123 | @end quotation | |
18fae2a8 | 6124 | |
29a2b744 | 6125 | @cindex Modula-2 built-ins |
4eb4cf57 | 6126 | @node Built-In Func/Proc |
c2bbbb22 RP |
6127 | @subsubsection Built-in Functions and Procedures |
6128 | ||
6129 | Modula-2 also makes available several built-in procedures and functions. | |
6130 | In describing these, the following metavariables are used: | |
6131 | ||
6132 | @table @var | |
6133 | ||
6134 | @item a | |
6135 | represents an @code{ARRAY} variable. | |
6136 | ||
6137 | @item c | |
6138 | represents a @code{CHAR} constant or variable. | |
6139 | ||
6140 | @item i | |
6141 | represents a variable or constant of integral type. | |
6142 | ||
6143 | @item m | |
6144 | represents an identifier that belongs to a set. Generally used in the | |
6145 | same function with the metavariable @var{s}. The type of @var{s} should | |
6146 | be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}. | |
6147 | ||
6148 | @item n | |
6149 | represents a variable or constant of integral or floating-point type. | |
6150 | ||
6151 | @item r | |
6152 | represents a variable or constant of floating-point type. | |
6153 | ||
6154 | @item t | |
6155 | represents a type. | |
6156 | ||
6157 | @item v | |
6158 | represents a variable. | |
6159 | ||
6160 | @item x | |
6161 | represents a variable or constant of one of many types. See the | |
6162 | explanation of the function for details. | |
c2bbbb22 RP |
6163 | @end table |
6164 | ||
6165 | All Modula-2 built-in procedures also return a result, described below. | |
6166 | ||
6167 | @table @code | |
6168 | @item ABS(@var{n}) | |
6169 | Returns the absolute value of @var{n}. | |
6170 | ||
6171 | @item CAP(@var{c}) | |
6172 | If @var{c} is a lower case letter, it returns its upper case | |
6173 | equivalent, otherwise it returns its argument | |
6174 | ||
6175 | @item CHR(@var{i}) | |
6176 | Returns the character whose ordinal value is @var{i}. | |
6177 | ||
6178 | @item DEC(@var{v}) | |
6179 | Decrements the value in the variable @var{v}. Returns the new value. | |
6180 | ||
6181 | @item DEC(@var{v},@var{i}) | |
6182 | Decrements the value in the variable @var{v} by @var{i}. Returns the | |
6183 | new value. | |
6184 | ||
6185 | @item EXCL(@var{m},@var{s}) | |
6186 | Removes the element @var{m} from the set @var{s}. Returns the new | |
6187 | set. | |
6188 | ||
6189 | @item FLOAT(@var{i}) | |
6190 | Returns the floating point equivalent of the integer @var{i}. | |
6191 | ||
6192 | @item HIGH(@var{a}) | |
6193 | Returns the index of the last member of @var{a}. | |
6194 | ||
6195 | @item INC(@var{v}) | |
6196 | Increments the value in the variable @var{v}. Returns the new value. | |
6197 | ||
6198 | @item INC(@var{v},@var{i}) | |
6199 | Increments the value in the variable @var{v} by @var{i}. Returns the | |
6200 | new value. | |
6201 | ||
6202 | @item INCL(@var{m},@var{s}) | |
6203 | Adds the element @var{m} to the set @var{s} if it is not already | |
6204 | there. Returns the new set. | |
6205 | ||
6206 | @item MAX(@var{t}) | |
6207 | Returns the maximum value of the type @var{t}. | |
6208 | ||
6209 | @item MIN(@var{t}) | |
6210 | Returns the minimum value of the type @var{t}. | |
6211 | ||
6212 | @item ODD(@var{i}) | |
6213 | Returns boolean TRUE if @var{i} is an odd number. | |
6214 | ||
6215 | @item ORD(@var{x}) | |
6216 | Returns the ordinal value of its argument. For example, the ordinal | |
6217 | value of a character is its ASCII value (on machines supporting the | |
6218 | ASCII character set). @var{x} must be of an ordered type, which include | |
6219 | integral, character and enumerated types. | |
6220 | ||
6221 | @item SIZE(@var{x}) | |
6222 | Returns the size of its argument. @var{x} can be a variable or a type. | |
6223 | ||
6224 | @item TRUNC(@var{r}) | |
6225 | Returns the integral part of @var{r}. | |
6226 | ||
6227 | @item VAL(@var{t},@var{i}) | |
6228 | Returns the member of the type @var{t} whose ordinal value is @var{i}. | |
6229 | @end table | |
6230 | ||
6231 | @quotation | |
6232 | @emph{Warning:} Sets and their operations are not yet supported, so | |
18fae2a8 | 6233 | @value{GDBN} will treat the use of procedures @code{INCL} and @code{EXCL} as |
c2bbbb22 RP |
6234 | an error. |
6235 | @end quotation | |
6236 | ||
6237 | @cindex Modula-2 constants | |
4eb4cf57 | 6238 | @node M2 Constants |
c2bbbb22 RP |
6239 | @subsubsection Constants |
6240 | ||
18fae2a8 | 6241 | @value{GDBN} allows you to express the constants of Modula-2 in the following |
c2bbbb22 RP |
6242 | ways: |
6243 | ||
6244 | @itemize @bullet | |
6245 | ||
6246 | @item | |
6247 | Integer constants are simply a sequence of digits. When used in an | |
6248 | expression, a constant is interpreted to be type-compatible with the | |
6249 | rest of the expression. Hexadecimal integers are specified by a | |
6250 | trailing @samp{H}, and octal integers by a trailing @samp{B}. | |
6251 | ||
6252 | @item | |
6253 | Floating point constants appear as a sequence of digits, followed by a | |
6254 | decimal point and another sequence of digits. An optional exponent can | |
6255 | then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where | |
6256 | @samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the | |
6257 | digits of the floating point constant must be valid decimal (base 10) | |
6258 | digits. | |
6259 | ||
6260 | @item | |
6261 | Character constants consist of a single character enclosed by a pair of | |
6262 | like quotes, either single (@code{'}) or double (@code{"}). They may | |
6263 | also be expressed by their ordinal value (their ASCII value, usually) | |
6264 | followed by a @samp{C}. | |
6265 | ||
6266 | @item | |
1041a570 RP |
6267 | String constants consist of a sequence of characters enclosed by a |
6268 | pair of like quotes, either single (@code{'}) or double (@code{"}). | |
6269 | Escape sequences in the style of C are also allowed. @xref{C | |
6270 | Constants, ,C and C++ Constants}, for a brief explanation of escape | |
6271 | sequences. | |
c2bbbb22 RP |
6272 | |
6273 | @item | |
6274 | Enumerated constants consist of an enumerated identifier. | |
6275 | ||
6276 | @item | |
6277 | Boolean constants consist of the identifiers @code{TRUE} and | |
6278 | @code{FALSE}. | |
6279 | ||
6280 | @item | |
6281 | Pointer constants consist of integral values only. | |
6282 | ||
6283 | @item | |
6284 | Set constants are not yet supported. | |
c2bbbb22 RP |
6285 | @end itemize |
6286 | ||
4eb4cf57 | 6287 | @node M2 Defaults |
c2bbbb22 RP |
6288 | @subsubsection Modula-2 Defaults |
6289 | @cindex Modula-2 defaults | |
6290 | ||
18fae2a8 | 6291 | If type and range checking are set automatically by @value{GDBN}, they |
e251e767 | 6292 | both default to @code{on} whenever the working language changes to |
18fae2a8 | 6293 | Modula-2. This happens regardless of whether you, or @value{GDBN}, |
c2bbbb22 RP |
6294 | selected the working language. |
6295 | ||
18fae2a8 | 6296 | If you allow @value{GDBN} to set the language automatically, then entering |
c2bbbb22 | 6297 | code compiled from a file whose name ends with @file{.mod} will set the |
18fae2a8 | 6298 | working language to Modula-2. @xref{Automatically, ,Having @value{GDBN} set |
c2bbbb22 RP |
6299 | the language automatically}, for further details. |
6300 | ||
4eb4cf57 | 6301 | @node Deviations |
c2bbbb22 RP |
6302 | @subsubsection Deviations from Standard Modula-2 |
6303 | @cindex Modula-2, deviations from | |
6304 | ||
6305 | A few changes have been made to make Modula-2 programs easier to debug. | |
6306 | This is done primarily via loosening its type strictness: | |
6307 | ||
6308 | @itemize @bullet | |
e251e767 | 6309 | @item |
c2bbbb22 RP |
6310 | Unlike in standard Modula-2, pointer constants can be formed by |
6311 | integers. This allows you to modify pointer variables during | |
6312 | debugging. (In standard Modula-2, the actual address contained in a | |
6313 | pointer variable is hidden from you; it can only be modified | |
6314 | through direct assignment to another pointer variable or expression that | |
6315 | returned a pointer.) | |
6316 | ||
e251e767 | 6317 | @item |
c2bbbb22 | 6318 | C escape sequences can be used in strings and characters to represent |
18fae2a8 | 6319 | non-printable characters. @value{GDBN} will print out strings with these |
c2bbbb22 RP |
6320 | escape sequences embedded. Single non-printable characters are |
6321 | printed using the @samp{CHR(@var{nnn})} format. | |
6322 | ||
6323 | @item | |
6324 | The assignment operator (@code{:=}) returns the value of its right-hand | |
6325 | argument. | |
6326 | ||
6327 | @item | |
29a2b744 | 6328 | All built-in procedures both modify @emph{and} return their argument. |
e251e767 | 6329 | @end itemize |
c2bbbb22 | 6330 | |
4eb4cf57 | 6331 | @node M2 Checks |
c2bbbb22 RP |
6332 | @subsubsection Modula-2 Type and Range Checks |
6333 | @cindex Modula-2 checks | |
6334 | ||
6335 | @quotation | |
18fae2a8 | 6336 | @emph{Warning:} in this release, @value{GDBN} does not yet perform type or |
c2bbbb22 RP |
6337 | range checking. |
6338 | @end quotation | |
6339 | @c FIXME remove warning when type/range checks added | |
6340 | ||
18fae2a8 | 6341 | @value{GDBN} considers two Modula-2 variables type equivalent if: |
c2bbbb22 RP |
6342 | |
6343 | @itemize @bullet | |
6344 | @item | |
6345 | They are of types that have been declared equivalent via a @code{TYPE | |
6346 | @var{t1} = @var{t2}} statement | |
6347 | ||
6348 | @item | |
6349 | They have been declared on the same line. (Note: This is true of the | |
6350 | GNU Modula-2 compiler, but it may not be true of other compilers.) | |
c2bbbb22 RP |
6351 | @end itemize |
6352 | ||
6353 | As long as type checking is enabled, any attempt to combine variables | |
6354 | whose types are not equivalent is an error. | |
6355 | ||
6356 | Range checking is done on all mathematical operations, assignment, array | |
29a2b744 | 6357 | index bounds, and all built-in functions and procedures. |
c2bbbb22 | 6358 | |
4eb4cf57 | 6359 | @node M2 Scope |
c2bbbb22 RP |
6360 | @subsubsection The scope operators @code{::} and @code{.} |
6361 | @cindex scope | |
6362 | @kindex . | |
e94b4a2b | 6363 | @cindex colon, doubled as scope operator |
1041a570 RP |
6364 | @ifinfo |
6365 | @kindex colon-colon | |
ed447b95 | 6366 | @c Info cannot handle :: but TeX can. |
1041a570 RP |
6367 | @end ifinfo |
6368 | @iftex | |
c2bbbb22 | 6369 | @kindex :: |
1041a570 | 6370 | @end iftex |
c2bbbb22 RP |
6371 | |
6372 | There are a few subtle differences between the Modula-2 scope operator | |
18fae2a8 | 6373 | (@code{.}) and the @value{GDBN} scope operator (@code{::}). The two have |
c2bbbb22 RP |
6374 | similar syntax: |
6375 | ||
6376 | @example | |
6377 | ||
6378 | @var{module} . @var{id} | |
6379 | @var{scope} :: @var{id} | |
c2bbbb22 RP |
6380 | @end example |
6381 | ||
6382 | @noindent | |
6383 | where @var{scope} is the name of a module or a procedure, | |
29a2b744 RP |
6384 | @var{module} the name of a module, and @var{id} is any declared |
6385 | identifier within your program, except another module. | |
c2bbbb22 | 6386 | |
18fae2a8 | 6387 | Using the @code{::} operator makes @value{GDBN} search the scope |
c2bbbb22 | 6388 | specified by @var{scope} for the identifier @var{id}. If it is not |
18fae2a8 | 6389 | found in the specified scope, then @value{GDBN} will search all scopes |
c2bbbb22 RP |
6390 | enclosing the one specified by @var{scope}. |
6391 | ||
18fae2a8 | 6392 | Using the @code{.} operator makes @value{GDBN} search the current scope for |
c2bbbb22 RP |
6393 | the identifier specified by @var{id} that was imported from the |
6394 | definition module specified by @var{module}. With this operator, it is | |
6395 | an error if the identifier @var{id} was not imported from definition | |
6396 | module @var{module}, or if @var{id} is not an identifier in | |
6397 | @var{module}. | |
6398 | ||
4eb4cf57 | 6399 | @node GDB/M2 |
18fae2a8 | 6400 | @subsubsection @value{GDBN} and Modula-2 |
c2bbbb22 | 6401 | |
18fae2a8 | 6402 | Some @value{GDBN} commands have little use when debugging Modula-2 programs. |
c2bbbb22 RP |
6403 | Five subcommands of @code{set print} and @code{show print} apply |
6404 | specifically to C and C++: @samp{vtbl}, @samp{demangle}, | |
6405 | @samp{asm-demangle}, @samp{object}, and @samp{union}. The first four | |
6406 | apply to C++, and the last to C's @code{union} type, which has no direct | |
6407 | analogue in Modula-2. | |
6408 | ||
1041a570 | 6409 | The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available |
c2bbbb22 RP |
6410 | while using any language, is not useful with Modula-2. Its |
6411 | intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be | |
6412 | created in Modula-2 as they can in C or C++. However, because an | |
6413 | address can be specified by an integral constant, the construct | |
1041a570 | 6414 | @samp{@{@var{type}@}@var{adrexp}} is still useful. (@pxref{Expressions, ,Expressions}) |
18fae2a8 | 6415 | |
c2bbbb22 | 6416 | @cindex @code{#} in Modula-2 |
18fae2a8 | 6417 | In @value{GDBN} scripts, the Modula-2 inequality operator @code{#} is |
c2bbbb22 | 6418 | interpreted as the beginning of a comment. Use @code{<>} instead. |
18fae2a8 RP |
6419 | |
6420 | @end ifclear | |
4eb4cf57 RP |
6421 | |
6422 | @node Symbols | |
70b88761 RP |
6423 | @chapter Examining the Symbol Table |
6424 | ||
6425 | The commands described in this section allow you to inquire about the | |
6426 | symbols (names of variables, functions and types) defined in your | |
6427 | program. This information is inherent in the text of your program and | |
18fae2a8 RP |
6428 | does not change as your program executes. @value{GDBN} finds it in your |
6429 | program's symbol table, in the file indicated when you started @value{GDBN} | |
1041a570 RP |
6430 | (@pxref{File Options, ,Choosing Files}), or by one of the |
6431 | file-management commands (@pxref{Files, ,Commands to Specify Files}). | |
70b88761 | 6432 | |
6c380b13 RP |
6433 | @c FIXME! This might be intentionally specific to C and C++; if so, move |
6434 | @c to someplace in C section of lang chapter. | |
6435 | @cindex symbol names | |
6436 | @cindex names of symbols | |
6437 | @cindex quoting names | |
6438 | Occasionally, you may need to refer to symbols that contain unusual | |
18fae2a8 | 6439 | characters, which @value{GDBN} ordinarily treats as word delimiters. The |
6c380b13 RP |
6440 | most frequent case is in referring to static variables in other |
6441 | source files (@pxref{Variables,,Program Variables}). File names | |
18fae2a8 | 6442 | are recorded in object files as debugging symbols, but @value{GDBN} would |
6c380b13 | 6443 | ordinarily parse a typical file name, like @file{foo.c}, as the three words |
18fae2a8 | 6444 | @samp{foo} @samp{.} @samp{c}. To allow @value{GDBN} to recognize |
6c380b13 RP |
6445 | @samp{foo.c} as a single symbol, enclose it in single quotes; for example, |
6446 | ||
6447 | @example | |
6448 | p 'foo.c'::x | |
6449 | @end example | |
6450 | ||
6451 | @noindent | |
6452 | looks up the value of @code{x} in the scope of the file @file{foo.c}. | |
6453 | ||
70b88761 RP |
6454 | @table @code |
6455 | @item info address @var{symbol} | |
6456 | @kindex info address | |
6457 | Describe where the data for @var{symbol} is stored. For a register | |
6458 | variable, this says which register it is kept in. For a non-register | |
6459 | local variable, this prints the stack-frame offset at which the variable | |
6460 | is always stored. | |
6461 | ||
6462 | Note the contrast with @samp{print &@var{symbol}}, which does not work | |
6463 | at all for a register variables, and for a stack local variable prints | |
6464 | the exact address of the current instantiation of the variable. | |
6465 | ||
6466 | @item whatis @var{exp} | |
6467 | @kindex whatis | |
6468 | Print the data type of expression @var{exp}. @var{exp} is not | |
6469 | actually evaluated, and any side-effecting operations (such as | |
6470 | assignments or function calls) inside it do not take place. | |
1041a570 | 6471 | @xref{Expressions, ,Expressions}. |
70b88761 RP |
6472 | |
6473 | @item whatis | |
6474 | Print the data type of @code{$}, the last value in the value history. | |
6475 | ||
6476 | @item ptype @var{typename} | |
6477 | @kindex ptype | |
6478 | Print a description of data type @var{typename}. @var{typename} may be | |
6479 | the name of a type, or for C code it may have the form | |
6480 | @samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or | |
1041a570 | 6481 | @samp{enum @var{enum-tag}}. |
70b88761 RP |
6482 | |
6483 | @item ptype @var{exp} | |
e0dacfd1 | 6484 | @itemx ptype |
70b88761 | 6485 | Print a description of the type of expression @var{exp}. @code{ptype} |
1041a570 | 6486 | differs from @code{whatis} by printing a detailed description, instead |
ed447b95 RP |
6487 | of just the name of the type. |
6488 | ||
6489 | For example, for this variable declaration: | |
1041a570 | 6490 | |
70b88761 RP |
6491 | @example |
6492 | struct complex @{double real; double imag;@} v; | |
6493 | @end example | |
1041a570 | 6494 | |
70b88761 | 6495 | @noindent |
ed447b95 | 6496 | the two commands give this output: |
1041a570 | 6497 | |
70b88761 | 6498 | @example |
1041a570 | 6499 | @group |
18fae2a8 | 6500 | (@value{GDBP}) whatis v |
70b88761 | 6501 | type = struct complex |
18fae2a8 | 6502 | (@value{GDBP}) ptype v |
70b88761 RP |
6503 | type = struct complex @{ |
6504 | double real; | |
6505 | double imag; | |
6506 | @} | |
1041a570 | 6507 | @end group |
70b88761 | 6508 | @end example |
1041a570 | 6509 | |
e0dacfd1 RP |
6510 | @noindent |
6511 | As with @code{whatis}, using @code{ptype} without an argument refers to | |
6512 | the type of @code{$}, the last value in the value history. | |
70b88761 RP |
6513 | |
6514 | @item info types @var{regexp} | |
6515 | @itemx info types | |
e251e767 | 6516 | @kindex info types |
70b88761 RP |
6517 | Print a brief description of all types whose name matches @var{regexp} |
6518 | (or all types in your program, if you supply no argument). Each | |
6519 | complete typename is matched as though it were a complete line; thus, | |
6520 | @samp{i type value} gives information on all types in your program whose | |
6521 | name includes the string @code{value}, but @samp{i type ^value$} gives | |
6522 | information only on types whose complete name is @code{value}. | |
6523 | ||
6524 | This command differs from @code{ptype} in two ways: first, like | |
6525 | @code{whatis}, it does not print a detailed description; second, it | |
6526 | lists all source files where a type is defined. | |
6527 | ||
6528 | @item info source | |
6529 | @kindex info source | |
6530 | Show the name of the current source file---that is, the source file for | |
c2bbbb22 RP |
6531 | the function containing the current point of execution---and the language |
6532 | it was written in. | |
70b88761 RP |
6533 | |
6534 | @item info sources | |
6535 | @kindex info sources | |
29a2b744 | 6536 | Print the names of all source files in your program for which there is |
b80282d5 RP |
6537 | debugging information, organized into two lists: files whose symbols |
6538 | have already been read, and files whose symbols will be read when needed. | |
70b88761 RP |
6539 | |
6540 | @item info functions | |
6541 | @kindex info functions | |
6542 | Print the names and data types of all defined functions. | |
6543 | ||
6544 | @item info functions @var{regexp} | |
6545 | Print the names and data types of all defined functions | |
6546 | whose names contain a match for regular expression @var{regexp}. | |
6547 | Thus, @samp{info fun step} finds all functions whose names | |
6548 | include @code{step}; @samp{info fun ^step} finds those whose names | |
6549 | start with @code{step}. | |
6550 | ||
6551 | @item info variables | |
6552 | @kindex info variables | |
6553 | Print the names and data types of all variables that are declared | |
6554 | outside of functions (i.e., excluding local variables). | |
6555 | ||
6556 | @item info variables @var{regexp} | |
6557 | Print the names and data types of all variables (except for local | |
6558 | variables) whose names contain a match for regular expression | |
6559 | @var{regexp}. | |
6560 | ||
70b88761 RP |
6561 | @ignore |
6562 | This was never implemented. | |
6563 | @item info methods | |
6564 | @itemx info methods @var{regexp} | |
6565 | @kindex info methods | |
6566 | The @code{info methods} command permits the user to examine all defined | |
6567 | methods within C++ program, or (with the @var{regexp} argument) a | |
6568 | specific set of methods found in the various C++ classes. Many | |
6569 | C++ classes provide a large number of methods. Thus, the output | |
6570 | from the @code{ptype} command can be overwhelming and hard to use. The | |
6571 | @code{info-methods} command filters the methods, printing only those | |
6572 | which match the regular-expression @var{regexp}. | |
6573 | @end ignore | |
6574 | ||
d48da190 RP |
6575 | @item maint print symbols @var{filename} |
6576 | @itemx maint print psymbols @var{filename} | |
6577 | @itemx maint print msymbols @var{filename} | |
6578 | @kindex maint print symbols | |
440d9834 | 6579 | @cindex symbol dump |
d48da190 | 6580 | @kindex maint print psymbols |
440d9834 RP |
6581 | @cindex partial symbol dump |
6582 | Write a dump of debugging symbol data into the file @var{filename}. | |
18fae2a8 | 6583 | These commands are used to debug the @value{GDBN} symbol-reading code. Only |
d48da190 | 6584 | symbols with debugging data are included. If you use @samp{maint print |
18fae2a8 | 6585 | symbols}, @value{GDBN} includes all the symbols for which it has already |
d48da190 | 6586 | collected full details: that is, @var{filename} reflects symbols for |
18fae2a8 | 6587 | only those files whose symbols @value{GDBN} has read. You can use the |
d48da190 RP |
6588 | command @code{info sources} to find out which files these are. If you |
6589 | use @samp{maint print psymbols} instead, the dump shows information about | |
18fae2a8 RP |
6590 | symbols that @value{GDBN} only knows partially---that is, symbols defined in |
6591 | files that @value{GDBN} has skimmed, but not yet read completely. Finally, | |
d48da190 | 6592 | @samp{maint print msymbols} dumps just the minimal symbol information |
18fae2a8 RP |
6593 | required for each object file from which @value{GDBN} has read some symbols. |
6594 | The description of @code{symbol-file} explains how @value{GDBN} reads | |
d48da190 RP |
6595 | symbols; both @code{info source} and @code{symbol-file} are described in |
6596 | @ref{Files, ,Commands to Specify Files}. | |
70b88761 RP |
6597 | @end table |
6598 | ||
4eb4cf57 | 6599 | @node Altering |
70b88761 RP |
6600 | @chapter Altering Execution |
6601 | ||
29a2b744 | 6602 | Once you think you have found an error in your program, you might want to |
70b88761 RP |
6603 | find out for certain whether correcting the apparent error would lead to |
6604 | correct results in the rest of the run. You can find the answer by | |
18fae2a8 | 6605 | experiment, using the @value{GDBN} features for altering execution of the |
70b88761 RP |
6606 | program. |
6607 | ||
6608 | For example, you can store new values into variables or memory | |
29a2b744 | 6609 | locations, give your program a signal, restart it at a different address, |
70b88761 RP |
6610 | or even return prematurely from a function to its caller. |
6611 | ||
18fae2a8 RP |
6612 | @ignore |
6613 | @c pre-unfold | |
70b88761 | 6614 | @menu |
ed447b95 RP |
6615 | * Assignment:: Assignment to variables |
6616 | * Jumping:: Continuing at a different address | |
18fae2a8 | 6617 | @ifclear BARETARGET |
ed447b95 | 6618 | * Signaling:: Giving your program a signal |
18fae2a8 | 6619 | @end ifclear |
ed447b95 RP |
6620 | * Returning:: Returning from a function |
6621 | * Calling:: Calling your program's functions | |
6622 | * Patching:: Patching your program | |
70b88761 | 6623 | @end menu |
18fae2a8 RP |
6624 | @end ignore |
6625 | ||
6626 | @ifclear BARETARGET | |
6627 | @menu | |
ed447b95 RP |
6628 | * Assignment:: Assignment to variables |
6629 | * Jumping:: Continuing at a different address | |
6630 | * Signaling:: Giving your program a signal | |
6631 | * Returning:: Returning from a function | |
6632 | * Calling:: Calling your program's functions | |
6633 | * Patching:: Patching your program | |
18fae2a8 RP |
6634 | @end menu |
6635 | @end ifclear | |
6636 | ||
6637 | @ifset BARETARGET | |
6638 | @menu | |
ed447b95 RP |
6639 | * Assignment:: Assignment to variables |
6640 | * Jumping:: Continuing at a different address | |
6641 | * Returning:: Returning from a function | |
6642 | * Calling:: Calling your program's functions | |
6643 | * Patching:: Patching your program | |
18fae2a8 RP |
6644 | @end menu |
6645 | @end ifset | |
70b88761 | 6646 | |
4eb4cf57 | 6647 | @node Assignment |
70b88761 RP |
6648 | @section Assignment to Variables |
6649 | ||
6650 | @cindex assignment | |
6651 | @cindex setting variables | |
6652 | To alter the value of a variable, evaluate an assignment expression. | |
1041a570 | 6653 | @xref{Expressions, ,Expressions}. For example, |
70b88761 RP |
6654 | |
6655 | @example | |
6656 | print x=4 | |
6657 | @end example | |
6658 | ||
6659 | @noindent | |
1041a570 | 6660 | stores the value 4 into the variable @code{x}, and then prints the |
4eb4cf57 | 6661 | value of the assignment expression (which is 4). |
18fae2a8 RP |
6662 | @ifclear CONLY |
6663 | @xref{Languages, ,Using @value{GDBN} with Different Languages}, for more | |
4eb4cf57 | 6664 | information on operators in supported languages. |
18fae2a8 | 6665 | @end ifclear |
70b88761 | 6666 | |
70b88761 RP |
6667 | @kindex set variable |
6668 | @cindex variables, setting | |
6669 | If you are not interested in seeing the value of the assignment, use the | |
6670 | @code{set} command instead of the @code{print} command. @code{set} is | |
6671 | really the same as @code{print} except that the expression's value is not | |
1041a570 | 6672 | printed and is not put in the value history (@pxref{Value History, ,Value History}). The |
70b88761 RP |
6673 | expression is evaluated only for its effects. |
6674 | ||
6675 | If the beginning of the argument string of the @code{set} command | |
6676 | appears identical to a @code{set} subcommand, use the @code{set | |
6677 | variable} command instead of just @code{set}. This command is identical | |
ed447b95 RP |
6678 | to @code{set} except for its lack of subcommands. For example, if |
6679 | your program has a variable @code{width}, you get | |
6680 | an error if you try to set a new value with just @samp{set width=13}, | |
6681 | because @value{GDBN} has the command @code{set width}: | |
1041a570 | 6682 | |
70b88761 | 6683 | @example |
18fae2a8 | 6684 | (@value{GDBP}) whatis width |
70b88761 | 6685 | type = double |
18fae2a8 | 6686 | (@value{GDBP}) p width |
70b88761 | 6687 | $4 = 13 |
18fae2a8 | 6688 | (@value{GDBP}) set width=47 |
70b88761 RP |
6689 | Invalid syntax in expression. |
6690 | @end example | |
1041a570 | 6691 | |
70b88761 | 6692 | @noindent |
ed447b95 RP |
6693 | The invalid expression, of course, is @samp{=47}. In |
6694 | order to actually set the program's variable @code{width}, use | |
1041a570 | 6695 | |
70b88761 | 6696 | @example |
18fae2a8 | 6697 | (@value{GDBP}) set var width=47 |
70b88761 RP |
6698 | @end example |
6699 | ||
18fae2a8 | 6700 | @value{GDBN} allows more implicit conversions in assignments than C; you can |
1041a570 | 6701 | freely store an integer value into a pointer variable or vice versa, |
ed447b95 | 6702 | and you can convert any structure to any other structure that is the |
1041a570 | 6703 | same length or shorter. |
e251e767 | 6704 | @comment FIXME: how do structs align/pad in these conversions? |
70b88761 RP |
6705 | @comment /pesch@cygnus.com 18dec1990 |
6706 | ||
6707 | To store values into arbitrary places in memory, use the @samp{@{@dots{}@}} | |
6708 | construct to generate a value of specified type at a specified address | |
1041a570 | 6709 | (@pxref{Expressions, ,Expressions}). For example, @code{@{int@}0x83040} refers |
70b88761 RP |
6710 | to memory location @code{0x83040} as an integer (which implies a certain size |
6711 | and representation in memory), and | |
6712 | ||
6713 | @example | |
6714 | set @{int@}0x83040 = 4 | |
6715 | @end example | |
6716 | ||
6717 | @noindent | |
6718 | stores the value 4 into that memory location. | |
6719 | ||
4eb4cf57 | 6720 | @node Jumping |
70b88761 RP |
6721 | @section Continuing at a Different Address |
6722 | ||
29a2b744 | 6723 | Ordinarily, when you continue your program, you do so at the place where |
70b88761 RP |
6724 | it stopped, with the @code{continue} command. You can instead continue at |
6725 | an address of your own choosing, with the following commands: | |
6726 | ||
6727 | @table @code | |
6728 | @item jump @var{linespec} | |
6729 | @kindex jump | |
6730 | Resume execution at line @var{linespec}. Execution will stop | |
29a2b744 RP |
6731 | immediately if there is a breakpoint there. @xref{List, ,Printing |
6732 | Source Lines}, for a description of the different forms of | |
6733 | @var{linespec}. | |
70b88761 RP |
6734 | |
6735 | The @code{jump} command does not change the current stack frame, or | |
6736 | the stack pointer, or the contents of any memory location or any | |
6737 | register other than the program counter. If line @var{linespec} is in | |
6738 | a different function from the one currently executing, the results may | |
6739 | be bizarre if the two functions expect different patterns of arguments or | |
6740 | of local variables. For this reason, the @code{jump} command requests | |
6741 | confirmation if the specified line is not in the function currently | |
6742 | executing. However, even bizarre results are predictable if you are | |
29a2b744 | 6743 | well acquainted with the machine-language code of your program. |
70b88761 RP |
6744 | |
6745 | @item jump *@var{address} | |
6746 | Resume execution at the instruction at address @var{address}. | |
6747 | @end table | |
6748 | ||
6749 | You can get much the same effect as the @code{jump} command by storing a | |
6750 | new value into the register @code{$pc}. The difference is that this | |
29a2b744 | 6751 | does not start your program running; it only changes the address where it |
70b88761 RP |
6752 | @emph{will} run when it is continued. For example, |
6753 | ||
6754 | @example | |
6755 | set $pc = 0x485 | |
6756 | @end example | |
6757 | ||
6758 | @noindent | |
6759 | causes the next @code{continue} command or stepping command to execute at | |
1041a570 RP |
6760 | address @code{0x485}, rather than at the address where your program stopped. |
6761 | @xref{Continuing and Stepping, ,Continuing and Stepping}. | |
70b88761 RP |
6762 | |
6763 | The most common occasion to use the @code{jump} command is to back up, | |
6764 | perhaps with more breakpoints set, over a portion of a program that has | |
6765 | already executed, in order to examine its execution in more detail. | |
6766 | ||
18fae2a8 | 6767 | @ifclear BARETARGET |
70b88761 | 6768 | @c @group |
ed447b95 RP |
6769 | @node Signaling |
6770 | @section Giving your program a signal | |
70b88761 RP |
6771 | |
6772 | @table @code | |
6773 | @item signal @var{signalnum} | |
6774 | @kindex signal | |
29a2b744 | 6775 | Resume execution where your program stopped, but give it immediately the |
70b88761 RP |
6776 | signal number @var{signalnum}. |
6777 | ||
6778 | Alternatively, if @var{signalnum} is zero, continue execution without | |
29a2b744 | 6779 | giving a signal. This is useful when your program stopped on account of |
70b88761 RP |
6780 | a signal and would ordinary see the signal when resumed with the |
6781 | @code{continue} command; @samp{signal 0} causes it to resume without a | |
6782 | signal. | |
6783 | ||
6784 | @code{signal} does not repeat when you press @key{RET} a second time | |
6785 | after executing the command. | |
6786 | @end table | |
6787 | @c @end group | |
18fae2a8 | 6788 | @end ifclear |
70b88761 | 6789 | |
4eb4cf57 | 6790 | @node Returning |
70b88761 RP |
6791 | @section Returning from a Function |
6792 | ||
6793 | @table @code | |
6794 | @item return | |
6795 | @itemx return @var{expression} | |
6796 | @cindex returning from a function | |
6797 | @kindex return | |
6798 | You can cancel execution of a function call with the @code{return} | |
6799 | command. If you give an | |
6800 | @var{expression} argument, its value is used as the function's return | |
e251e767 | 6801 | value. |
70b88761 RP |
6802 | @end table |
6803 | ||
18fae2a8 | 6804 | When you use @code{return}, @value{GDBN} discards the selected stack frame |
70b88761 RP |
6805 | (and all frames within it). You can think of this as making the |
6806 | discarded frame return prematurely. If you wish to specify a value to | |
6807 | be returned, give that value as the argument to @code{return}. | |
6808 | ||
29a2b744 RP |
6809 | This pops the selected stack frame (@pxref{Selection, ,Selecting a |
6810 | Frame}), and any other frames inside of it, leaving its caller as the | |
6811 | innermost remaining frame. That frame becomes selected. The | |
6812 | specified value is stored in the registers used for returning values | |
6813 | of functions. | |
70b88761 RP |
6814 | |
6815 | The @code{return} command does not resume execution; it leaves the | |
6816 | program stopped in the state that would exist if the function had just | |
1041a570 RP |
6817 | returned. In contrast, the @code{finish} command (@pxref{Continuing |
6818 | and Stepping, ,Continuing and Stepping}) resumes execution until the | |
6819 | selected stack frame returns naturally. | |
70b88761 | 6820 | |
4eb4cf57 | 6821 | @node Calling |
ed447b95 | 6822 | @section Calling program functions |
70b88761 RP |
6823 | |
6824 | @cindex calling functions | |
6825 | @kindex call | |
6826 | @table @code | |
6827 | @item call @var{expr} | |
6828 | Evaluate the expression @var{expr} without displaying @code{void} | |
6829 | returned values. | |
6830 | @end table | |
6831 | ||
6832 | You can use this variant of the @code{print} command if you want to | |
6833 | execute a function from your program, but without cluttering the output | |
6834 | with @code{void} returned values. The result is printed and saved in | |
6835 | the value history, if it is not void. | |
6836 | ||
4eb4cf57 | 6837 | @node Patching |
ed447b95 | 6838 | @section Patching programs |
c338a2fd RP |
6839 | @cindex patching binaries |
6840 | @cindex writing into executables | |
6841 | @cindex writing into corefiles | |
1041a570 | 6842 | |
18fae2a8 | 6843 | By default, @value{GDBN} opens the file containing your program's executable |
c338a2fd RP |
6844 | code (or the corefile) read-only. This prevents accidental alterations |
6845 | to machine code; but it also prevents you from intentionally patching | |
6846 | your program's binary. | |
6847 | ||
6848 | If you'd like to be able to patch the binary, you can specify that | |
6849 | explicitly with the @code{set write} command. For example, you might | |
6850 | want to turn on internal debugging flags, or even to make emergency | |
e251e767 | 6851 | repairs. |
c338a2fd RP |
6852 | |
6853 | @table @code | |
6854 | @item set write on | |
6855 | @itemx set write off | |
6856 | @kindex set write | |
18fae2a8 RP |
6857 | If you specify @samp{set write on}, @value{GDBN} will open executable |
6858 | @ifclear BARETARGET | |
0f153e74 | 6859 | and core |
18fae2a8 | 6860 | @end ifclear |
0f153e74 | 6861 | files for both reading and writing; if you specify @samp{set write |
18fae2a8 | 6862 | off} (the default), @value{GDBN} will open them read-only. |
c338a2fd | 6863 | |
1041a570 | 6864 | If you have already loaded a file, you must load it |
c338a2fd RP |
6865 | again (using the @code{exec-file} or @code{core-file} command) after |
6866 | changing @code{set write}, for your new setting to take effect. | |
6867 | ||
6868 | @item show write | |
7d7ff5f6 | 6869 | @kindex show write |
0f153e74 | 6870 | Display whether executable files |
18fae2a8 | 6871 | @ifclear BARETARGET |
0f153e74 | 6872 | and core files |
18fae2a8 | 6873 | @end ifclear |
0f153e74 | 6874 | will be opened for writing as well as reading. |
c338a2fd RP |
6875 | @end table |
6876 | ||
18fae2a8 RP |
6877 | @node GDB Files |
6878 | @chapter @value{GDBN}'s Files | |
70b88761 | 6879 | |
18fae2a8 | 6880 | @value{GDBN} needs to know the file name of the program to be debugged, both in |
4eb4cf57 | 6881 | order to read its symbol table and in order to start your program. |
18fae2a8 RP |
6882 | @ifclear BARETARGET |
6883 | To debug a core dump of a previous run, @value{GDBN} must be told the file | |
4eb4cf57 | 6884 | name of the core dump. |
18fae2a8 | 6885 | @end ifclear |
1041a570 | 6886 | |
70b88761 | 6887 | @menu |
ed447b95 RP |
6888 | * Files:: Commands to specify files |
6889 | * Symbol Errors:: Errors reading symbol files | |
70b88761 RP |
6890 | @end menu |
6891 | ||
4eb4cf57 | 6892 | @node Files |
70b88761 | 6893 | @section Commands to Specify Files |
70b88761 | 6894 | @cindex symbol table |
70b88761 | 6895 | |
18fae2a8 | 6896 | @ifclear BARETARGET |
0f153e74 | 6897 | @cindex core dump file |
1041a570 | 6898 | The usual way to specify executable and core dump file names is with |
ed447b95 | 6899 | the command arguments given when you start @value{GDBN} (@pxref{Invocation, |
18fae2a8 RP |
6900 | ,Getting In and Out of @value{GDBN}}. |
6901 | @end ifclear | |
6902 | @ifset BARETARGET | |
4eb4cf57 | 6903 | The usual way to specify an executable file name is with |
18fae2a8 RP |
6904 | the command argument given when you start @value{GDBN}, (@pxref{Invocation, |
6905 | ,Getting In and Out of @value{GDBN}}. | |
6906 | @end ifset | |
70b88761 RP |
6907 | |
6908 | Occasionally it is necessary to change to a different file during a | |
18fae2a8 RP |
6909 | @value{GDBN} session. Or you may run @value{GDBN} and forget to specify a file you |
6910 | want to use. In these situations the @value{GDBN} commands to specify new files | |
70b88761 RP |
6911 | are useful. |
6912 | ||
6913 | @table @code | |
6914 | @item file @var{filename} | |
6915 | @cindex executable file | |
6916 | @kindex file | |
6917 | Use @var{filename} as the program to be debugged. It is read for its | |
6918 | symbols and for the contents of pure memory. It is also the program | |
6919 | executed when you use the @code{run} command. If you do not specify a | |
18fae2a8 | 6920 | directory and the file is not found in @value{GDBN}'s working directory, @value{GDBN} |
1041a570 RP |
6921 | uses the environment variable @code{PATH} as a list of directories to |
6922 | search, just as the shell does when looking for a program to run. You | |
18fae2a8 | 6923 | can change the value of this variable, for both @value{GDBN} and your program, |
1041a570 | 6924 | using the @code{path} command. |
70b88761 | 6925 | |
14d01801 RP |
6926 | On systems with memory-mapped files, an auxiliary symbol table file |
6927 | @file{@var{filename}.syms} may be available for @var{filename}. If it | |
18fae2a8 | 6928 | is, @value{GDBN} will map in the symbol table from |
14d01801 | 6929 | @file{@var{filename}.syms}, starting up more quickly. See the |
95d5ceb9 | 6930 | descriptions of the options @samp{-mapped} and @samp{-readnow} (available |
77b46d13 JG |
6931 | on the command line, and with the commands @code{file}, @code{symbol-file}, |
6932 | or @code{add-symbol-file}), for more information. | |
14d01801 | 6933 | |
e0dacfd1 | 6934 | @item file |
18fae2a8 | 6935 | @code{file} with no argument makes @value{GDBN} discard any information it |
70b88761 RP |
6936 | has on both executable file and the symbol table. |
6937 | ||
e0dacfd1 | 6938 | @item exec-file @r{[} @var{filename} @r{]} |
70b88761 RP |
6939 | @kindex exec-file |
6940 | Specify that the program to be run (but not the symbol table) is found | |
18fae2a8 | 6941 | in @var{filename}. @value{GDBN} will search the environment variable @code{PATH} |
29a2b744 | 6942 | if necessary to locate your program. Omitting @var{filename} means to |
e0dacfd1 | 6943 | discard information on the executable file. |
70b88761 | 6944 | |
e0dacfd1 | 6945 | @item symbol-file @r{[} @var{filename} @r{]} |
70b88761 RP |
6946 | @kindex symbol-file |
6947 | Read symbol table information from file @var{filename}. @code{PATH} is | |
6948 | searched when necessary. Use the @code{file} command to get both symbol | |
6949 | table and program to run from the same file. | |
6950 | ||
18fae2a8 | 6951 | @code{symbol-file} with no argument clears out @value{GDBN}'s information on your |
70b88761 RP |
6952 | program's symbol table. |
6953 | ||
18fae2a8 | 6954 | The @code{symbol-file} command causes @value{GDBN} to forget the contents of its |
70b88761 RP |
6955 | convenience variables, the value history, and all breakpoints and |
6956 | auto-display expressions. This is because they may contain pointers to | |
6957 | the internal data recording symbols and data types, which are part of | |
18fae2a8 | 6958 | the old symbol table data being discarded inside @value{GDBN}. |
70b88761 RP |
6959 | |
6960 | @code{symbol-file} will not repeat if you press @key{RET} again after | |
6961 | executing it once. | |
6962 | ||
18fae2a8 | 6963 | When @value{GDBN} is configured for a particular environment, it will |
14d01801 RP |
6964 | understand debugging information in whatever format is the standard |
6965 | generated for that environment; you may use either a GNU compiler, or | |
6966 | other compilers that adhere to the local conventions. Best results are | |
18fae2a8 | 6967 | usually obtained from GNU compilers; for example, using @code{@value{GCC}} |
14d01801 RP |
6968 | you can generate debugging information for optimized code. |
6969 | ||
70b88761 | 6970 | On some kinds of object files, the @code{symbol-file} command does not |
14d01801 | 6971 | normally read the symbol table in full right away. Instead, it scans |
70b88761 RP |
6972 | the symbol table quickly to find which source files and which symbols |
6973 | are present. The details are read later, one source file at a time, | |
1041a570 | 6974 | as they are needed. |
70b88761 | 6975 | |
18fae2a8 | 6976 | The purpose of this two-stage reading strategy is to make @value{GDBN} start up |
1041a570 RP |
6977 | faster. For the most part, it is invisible except for occasional |
6978 | pauses while the symbol table details for a particular source file are | |
6979 | being read. (The @code{set verbose} command can turn these pauses | |
ed447b95 | 6980 | into messages if desired. @xref{Messages/Warnings, ,Optional Warnings |
1041a570 | 6981 | and Messages}.) |
70b88761 RP |
6982 | |
6983 | When the symbol table is stored in COFF format, @code{symbol-file} does | |
1041a570 | 6984 | read the symbol table data in full right away. We have not implemented |
70b88761 RP |
6985 | the two-stage strategy for COFF yet. |
6986 | ||
95d5ceb9 RP |
6987 | @item symbol-file @var{filename} @r{[} -readnow @r{]} @r{[} -mapped @r{]} |
6988 | @itemx file @var{filename} @r{[} -readnow @r{]} @r{[} -mapped @r{]} | |
14d01801 RP |
6989 | @kindex readnow |
6990 | @cindex reading symbols immediately | |
6991 | @cindex symbols, reading immediately | |
6992 | @kindex mapped | |
6993 | @cindex memory-mapped symbol file | |
38962738 | 6994 | @cindex saving symbol table |
18fae2a8 | 6995 | You can override the @value{GDBN} two-stage strategy for reading symbol |
95d5ceb9 | 6996 | tables by using the @samp{-readnow} option with any of the commands that |
18fae2a8 | 6997 | load symbol table information, if you want to be sure @value{GDBN} has the |
14d01801 RP |
6998 | entire symbol table available. |
6999 | ||
18fae2a8 | 7000 | @ifclear BARETARGET |
14d01801 | 7001 | If memory-mapped files are available on your system through the |
95d5ceb9 | 7002 | @code{mmap} system call, you can use another option, @samp{-mapped}, to |
18fae2a8 RP |
7003 | cause @value{GDBN} to write the symbols for your program into a reusable |
7004 | file. Future @value{GDBN} debugging sessions will map in symbol information | |
77b46d13 JG |
7005 | from this auxiliary symbol file (if the program hasn't changed), rather |
7006 | than spending time reading the symbol table from the executable | |
7007 | program. Using the @samp{-mapped} option has the same effect as | |
18fae2a8 | 7008 | starting @value{GDBN} with the @samp{-mapped} command-line option. |
14d01801 | 7009 | |
95d5ceb9 | 7010 | You can use both options together, to make sure the auxiliary symbol |
14d01801 RP |
7011 | file has all the symbol information for your program. |
7012 | ||
77b46d13 JG |
7013 | The @code{.syms} file is specific to the host machine on which GDB is run. |
7014 | It holds an exact image of GDB's internal symbol table. It cannot be | |
7015 | shared across multiple host platforms. | |
7016 | ||
14d01801 RP |
7017 | The auxiliary symbol file for a program called @var{myprog} is called |
7018 | @samp{@var{myprog}.syms}. Once this file exists (so long as it is newer | |
18fae2a8 | 7019 | than the corresponding executable), @value{GDBN} will always attempt to use |
14d01801 RP |
7020 | it when you debug @var{myprog}; no special options or commands are |
7021 | needed. | |
7022 | @c FIXME: for now no mention of directories, since this seems to be in | |
7023 | @c flux. 13mar1992 status is that in theory GDB would look either in | |
7024 | @c current dir or in same dir as myprog; but issues like competing | |
7025 | @c GDB's, or clutter in system dirs, mean that in practice right now | |
7026 | @c only current dir is used. FFish says maybe a special GDB hierarchy | |
7027 | @c (eg rooted in val of env var GDBSYMS) could exist for mappable symbol | |
7028 | @c files. | |
70b88761 | 7029 | |
e0dacfd1 | 7030 | @item core-file @r{[} @var{filename} @r{]} |
70b88761 RP |
7031 | @kindex core |
7032 | @kindex core-file | |
7033 | Specify the whereabouts of a core dump file to be used as the ``contents | |
7034 | of memory''. Traditionally, core files contain only some parts of the | |
18fae2a8 | 7035 | address space of the process that generated them; @value{GDBN} can access the |
70b88761 RP |
7036 | executable file itself for other parts. |
7037 | ||
7038 | @code{core-file} with no argument specifies that no core file is | |
7039 | to be used. | |
7040 | ||
7041 | Note that the core file is ignored when your program is actually running | |
18fae2a8 | 7042 | under @value{GDBN}. So, if you have been running your program and you wish to |
70b88761 RP |
7043 | debug a core file instead, you must kill the subprocess in which the |
7044 | program is running. To do this, use the @code{kill} command | |
1041a570 | 7045 | (@pxref{Kill Process, ,Killing the Child Process}). |
18fae2a8 | 7046 | @end ifclear |
70b88761 RP |
7047 | |
7048 | @item load @var{filename} | |
7049 | @kindex load | |
18fae2a8 | 7050 | @ifset GENERIC |
70b88761 | 7051 | Depending on what remote debugging facilities are configured into |
18fae2a8 | 7052 | @value{GDBN}, the @code{load} command may be available. Where it exists, it |
70b88761 RP |
7053 | is meant to make @var{filename} (an executable) available for debugging |
7054 | on the remote system---by downloading, or dynamic linking, for example. | |
18fae2a8 | 7055 | @code{load} also records @var{filename}'s symbol table in @value{GDBN}, like |
70b88761 RP |
7056 | the @code{add-symbol-file} command. |
7057 | ||
ed447b95 RP |
7058 | If your @value{GDBN} does not have a @code{load} command, attempting to |
7059 | execute it gets the error message ``@code{You can't do that when your | |
7060 | target is @dots{}}'' | |
18fae2a8 | 7061 | @end ifset |
70b88761 | 7062 | |
18fae2a8 | 7063 | @ifset VXWORKS |
70b88761 | 7064 | On VxWorks, @code{load} will dynamically link @var{filename} on the |
18fae2a8 RP |
7065 | current target system as well as adding its symbols in @value{GDBN}. |
7066 | @end ifset | |
70b88761 | 7067 | |
18fae2a8 | 7068 | @ifset Icmlx |
70b88761 RP |
7069 | @cindex download to Nindy-960 |
7070 | With the Nindy interface to an Intel 960 board, @code{load} will | |
7071 | download @var{filename} to the 960 as well as adding its symbols in | |
18fae2a8 RP |
7072 | @value{GDBN}. |
7073 | @end ifset | |
70b88761 | 7074 | |
18fae2a8 | 7075 | @ifset Hviii |
c7cb8acb RP |
7076 | @cindex download to H8/300 |
7077 | @cindex H8/300 download | |
7078 | When you select remote debugging to a Hitachi H8/300 board (@pxref{Hitachi | |
18fae2a8 | 7079 | H8/300 Remote,,@value{GDBN} and the Hitachi H8/300}), the |
c7cb8acb | 7080 | @code{load} command downloads your program to the H8/300 and also opens |
18fae2a8 | 7081 | it as the current executable target for @value{GDBN} on your host (like the |
c7cb8acb | 7082 | @code{file} command). |
18fae2a8 | 7083 | @end ifset |
c7cb8acb | 7084 | |
70b88761 RP |
7085 | @code{load} will not repeat if you press @key{RET} again after using it. |
7086 | ||
18fae2a8 | 7087 | @ifclear BARETARGET |
70b88761 | 7088 | @item add-symbol-file @var{filename} @var{address} |
95d5ceb9 | 7089 | @itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]} @r{[} -mapped @r{]} |
70b88761 RP |
7090 | @kindex add-symbol-file |
7091 | @cindex dynamic linking | |
7092 | The @code{add-symbol-file} command reads additional symbol table information | |
b80282d5 | 7093 | from the file @var{filename}. You would use this command when @var{filename} |
70b88761 RP |
7094 | has been dynamically loaded (by some other means) into the program that |
7095 | is running. @var{address} should be the memory address at which the | |
18fae2a8 | 7096 | file has been loaded; @value{GDBN} cannot figure this out for itself. |
70b88761 RP |
7097 | |
7098 | The symbol table of the file @var{filename} is added to the symbol table | |
7099 | originally read with the @code{symbol-file} command. You can use the | |
7100 | @code{add-symbol-file} command any number of times; the new symbol data thus | |
7101 | read keeps adding to the old. To discard all old symbol data instead, | |
e251e767 | 7102 | use the @code{symbol-file} command. |
70b88761 RP |
7103 | |
7104 | @code{add-symbol-file} will not repeat if you press @key{RET} after using it. | |
7105 | ||
95d5ceb9 | 7106 | You can use the @samp{-mapped} and @samp{-readnow} options just as with |
18fae2a8 | 7107 | the @code{symbol-file} command, to change how @value{GDBN} manages the symbol |
0f153e74 | 7108 | table information for @var{filename}. |
18fae2a8 | 7109 | @end ifclear |
95d5ceb9 | 7110 | |
70b88761 RP |
7111 | @item info files |
7112 | @itemx info target | |
7113 | @kindex info files | |
7114 | @kindex info target | |
1041a570 RP |
7115 | @code{info files} and @code{info target} are synonymous; both print |
7116 | the current targets (@pxref{Targets, ,Specifying a Debugging Target}), | |
7117 | including the names of the executable and core dump files currently in | |
18fae2a8 | 7118 | use by @value{GDBN}, and the files from which symbols were loaded. The command |
1041a570 RP |
7119 | @code{help targets} lists all possible targets rather than current |
7120 | ones. | |
70b88761 RP |
7121 | @end table |
7122 | ||
7123 | All file-specifying commands allow both absolute and relative file names | |
18fae2a8 | 7124 | as arguments. @value{GDBN} always converts the file name to an absolute path |
70b88761 RP |
7125 | name and remembers it that way. |
7126 | ||
18fae2a8 | 7127 | @ifclear BARETARGET |
70b88761 | 7128 | @cindex shared libraries |
18fae2a8 RP |
7129 | @value{GDBN} supports SunOS, SVR4, and IBM RS/6000 shared libraries. |
7130 | @value{GDBN} automatically loads symbol definitions from shared libraries | |
77b46d13 | 7131 | when you use the @code{run} command, or when you examine a core file. |
18fae2a8 | 7132 | (Before you issue the @code{run} command, @value{GDBN} will not understand |
77b46d13 JG |
7133 | references to a function in a shared library, however---unless you are |
7134 | debugging a core file). | |
18fae2a8 | 7135 | @c FIXME: next @value{GDBN} release should permit some refs to undef |
1041a570 | 7136 | @c FIXME...symbols---eg in a break cmd---assuming they are from a shared lib |
70b88761 RP |
7137 | |
7138 | @table @code | |
70b88761 RP |
7139 | @item info share |
7140 | @itemx info sharedlibrary | |
7141 | @kindex info sharedlibrary | |
7142 | @kindex info share | |
c338a2fd | 7143 | Print the names of the shared libraries which are currently loaded. |
70b88761 | 7144 | |
c338a2fd RP |
7145 | @item sharedlibrary @var{regex} |
7146 | @itemx share @var{regex} | |
7147 | @kindex sharedlibrary | |
7148 | @kindex share | |
7149 | This is an obsolescent command; you can use it to explicitly | |
7150 | load shared object library symbols for files matching a UNIX regular | |
7151 | expression, but as with files loaded automatically, it will only load | |
7152 | shared libraries required by your program for a core file or after | |
7153 | typing @code{run}. If @var{regex} is omitted all shared libraries | |
7154 | required by your program are loaded. | |
7155 | @end table | |
18fae2a8 | 7156 | @end ifclear |
70b88761 | 7157 | |
4eb4cf57 | 7158 | @node Symbol Errors |
70b88761 | 7159 | @section Errors Reading Symbol Files |
1041a570 | 7160 | |
18fae2a8 | 7161 | While reading a symbol file, @value{GDBN} will occasionally encounter problems, |
1041a570 | 7162 | such as symbol types it does not recognize, or known bugs in compiler |
18fae2a8 | 7163 | output. By default, @value{GDBN} does not notify you of such problems, since |
1041a570 RP |
7164 | they are relatively common and primarily of interest to people |
7165 | debugging compilers. If you are interested in seeing information | |
18fae2a8 | 7166 | about ill-constructed symbol tables, you can either ask @value{GDBN} to print |
b80282d5 | 7167 | only one message about each such type of problem, no matter how many |
18fae2a8 | 7168 | times the problem occurs; or you can ask @value{GDBN} to print more messages, |
1041a570 RP |
7169 | to see how many times the problems occur, with the @code{set |
7170 | complaints} command (@pxref{Messages/Warnings, ,Optional Warnings and | |
7171 | Messages}). | |
70b88761 RP |
7172 | |
7173 | The messages currently printed, and their meanings, are: | |
7174 | ||
7175 | @table @code | |
7176 | @item inner block not inside outer block in @var{symbol} | |
7177 | ||
7178 | The symbol information shows where symbol scopes begin and end | |
7179 | (such as at the start of a function or a block of statements). This | |
7180 | error indicates that an inner scope block is not fully contained | |
e251e767 | 7181 | in its outer scope blocks. |
70b88761 | 7182 | |
18fae2a8 | 7183 | @value{GDBN} circumvents the problem by treating the inner block as if it had |
70b88761 RP |
7184 | the same scope as the outer block. In the error message, @var{symbol} |
7185 | may be shown as ``@code{(don't know)}'' if the outer block is not a | |
7186 | function. | |
7187 | ||
7188 | @item block at @var{address} out of order | |
7189 | ||
e251e767 | 7190 | The symbol information for symbol scope blocks should occur in |
70b88761 | 7191 | order of increasing addresses. This error indicates that it does not |
e251e767 | 7192 | do so. |
70b88761 | 7193 | |
ed447b95 RP |
7194 | @value{GDBN} does not circumvent this problem, and will have trouble |
7195 | locating symbols in the source file whose symbols it is reading. (You | |
7196 | can often determine what source file is affected by specifying | |
7197 | @code{set verbose on}. @xref{Messages/Warnings, ,Optional Warnings and | |
7198 | Messages}.) | |
70b88761 RP |
7199 | |
7200 | @item bad block start address patched | |
7201 | ||
7202 | The symbol information for a symbol scope block has a start address | |
7203 | smaller than the address of the preceding source line. This is known | |
e251e767 | 7204 | to occur in the SunOS 4.1.1 (and earlier) C compiler. |
70b88761 | 7205 | |
18fae2a8 | 7206 | @value{GDBN} circumvents the problem by treating the symbol scope block as |
70b88761 RP |
7207 | starting on the previous source line. |
7208 | ||
70b88761 RP |
7209 | @item bad string table offset in symbol @var{n} |
7210 | ||
7211 | @cindex foo | |
7212 | Symbol number @var{n} contains a pointer into the string table which is | |
e251e767 | 7213 | larger than the size of the string table. |
70b88761 | 7214 | |
18fae2a8 | 7215 | @value{GDBN} circumvents the problem by considering the symbol to have the |
70b88761 RP |
7216 | name @code{foo}, which may cause other problems if many symbols end up |
7217 | with this name. | |
7218 | ||
7219 | @item unknown symbol type @code{0x@var{nn}} | |
7220 | ||
18fae2a8 | 7221 | The symbol information contains new data types that @value{GDBN} does not yet |
70b88761 | 7222 | know how to read. @code{0x@var{nn}} is the symbol type of the misunderstood |
e251e767 | 7223 | information, in hexadecimal. |
70b88761 | 7224 | |
18fae2a8 | 7225 | @value{GDBN} circumvents the error by ignoring this symbol information. This |
29a2b744 | 7226 | will usually allow your program to be debugged, though certain symbols |
70b88761 | 7227 | will not be accessible. If you encounter such a problem and feel like |
18fae2a8 | 7228 | debugging it, you can debug @code{@value{GDBP}} with itself, breakpoint on |
70b88761 RP |
7229 | @code{complain}, then go up to the function @code{read_dbx_symtab} and |
7230 | examine @code{*bufp} to see the symbol. | |
7231 | ||
7232 | @item stub type has NULL name | |
18fae2a8 | 7233 | @value{GDBN} could not find the full definition for a struct or class. |
70b88761 | 7234 | |
440d9834 | 7235 | @item const/volatile indicator missing (ok if using g++ v1.x), got@dots{} |
70b88761 RP |
7236 | |
7237 | The symbol information for a C++ member function is missing some | |
440d9834 RP |
7238 | information that recent versions of the compiler should have output |
7239 | for it. | |
70b88761 | 7240 | |
440d9834 | 7241 | @item info mismatch between compiler and debugger |
70b88761 | 7242 | |
18fae2a8 | 7243 | @value{GDBN} could not parse a type specification output by the compiler. |
70b88761 RP |
7244 | @end table |
7245 | ||
4eb4cf57 | 7246 | @node Targets |
e251e767 | 7247 | @chapter Specifying a Debugging Target |
70b88761 RP |
7248 | @cindex debugging target |
7249 | @kindex target | |
1041a570 | 7250 | |
cedaf8bc | 7251 | A @dfn{target} is the execution environment occupied by your program. |
18fae2a8 RP |
7252 | @ifclear BARETARGET |
7253 | Often, @value{GDBN} runs in the same host environment as your program; in | |
1041a570 RP |
7254 | that case, the debugging target is specified as a side effect when you |
7255 | use the @code{file} or @code{core} commands. When you need more | |
18fae2a8 | 7256 | flexibility---for example, running @value{GDBN} on a physically separate |
1041a570 | 7257 | host, or controlling a standalone system over a serial port or a |
0f153e74 | 7258 | realtime system over a TCP/IP connection---you |
18fae2a8 RP |
7259 | @end ifclear |
7260 | @ifset BARETARGET | |
0f153e74 | 7261 | You |
18fae2a8 | 7262 | @end ifset |
0f153e74 | 7263 | can use the @code{target} command to specify one of the target types |
18fae2a8 | 7264 | configured for @value{GDBN} (@pxref{Target Commands, ,Commands for Managing |
0f153e74 | 7265 | Targets}). |
70b88761 RP |
7266 | |
7267 | @menu | |
ed447b95 RP |
7268 | * Active Targets:: Active targets |
7269 | * Target Commands:: Commands for managing targets | |
7270 | * Remote:: Remote debugging | |
70b88761 RP |
7271 | @end menu |
7272 | ||
4eb4cf57 | 7273 | @node Active Targets |
70b88761 RP |
7274 | @section Active Targets |
7275 | @cindex stacking targets | |
7276 | @cindex active targets | |
7277 | @cindex multiple targets | |
7278 | ||
18fae2a8 | 7279 | @ifclear BARETARGET |
cedaf8bc | 7280 | There are three classes of targets: processes, core files, and |
18fae2a8 | 7281 | executable files. @value{GDBN} can work concurrently on up to three active |
cedaf8bc RP |
7282 | targets, one in each class. This allows you to (for example) start a |
7283 | process and inspect its activity without abandoning your work on a core | |
7284 | file. | |
70b88761 | 7285 | |
ed447b95 | 7286 | For example, if you execute @samp{gdb a.out}, then the executable file |
cedaf8bc RP |
7287 | @code{a.out} is the only active target. If you designate a core file as |
7288 | well---presumably from a prior run that crashed and coredumped---then | |
18fae2a8 | 7289 | @value{GDBN} has two active targets and will use them in tandem, looking |
cedaf8bc RP |
7290 | first in the corefile target, then in the executable file, to satisfy |
7291 | requests for memory addresses. (Typically, these two classes of target | |
29a2b744 | 7292 | are complementary, since core files contain only a program's |
cedaf8bc RP |
7293 | read-write memory---variables and so on---plus machine status, while |
7294 | executable files contain only the program text and initialized data.) | |
18fae2a8 | 7295 | @end ifclear |
cedaf8bc RP |
7296 | |
7297 | When you type @code{run}, your executable file becomes an active process | |
18fae2a8 | 7298 | target as well. When a process target is active, all @value{GDBN} commands |
0f153e74 | 7299 | requesting memory addresses refer to that target; addresses in an |
18fae2a8 | 7300 | @ifclear BARETARGET |
0f153e74 | 7301 | active core file or |
18fae2a8 | 7302 | @end ifclear |
0f153e74 | 7303 | executable file target are obscured while the process |
cedaf8bc RP |
7304 | target is active. |
7305 | ||
18fae2a8 | 7306 | @ifset BARETARGET |
4eb4cf57 RP |
7307 | Use the @code{exec-file} command to select a |
7308 | new executable target (@pxref{Files, ,Commands to Specify | |
7309 | Files}). | |
18fae2a8 RP |
7310 | @end ifset |
7311 | @ifclear BARETARGET | |
1041a570 RP |
7312 | Use the @code{core-file} and @code{exec-file} commands to select a |
7313 | new core file or executable target (@pxref{Files, ,Commands to Specify | |
7314 | Files}). To specify as a target a process that is already running, use | |
7315 | the @code{attach} command (@pxref{Attach, ,Debugging an | |
ed447b95 | 7316 | Already-Running Process}). |
18fae2a8 | 7317 | @end ifclear |
70b88761 | 7318 | |
4eb4cf57 | 7319 | @node Target Commands |
70b88761 RP |
7320 | @section Commands for Managing Targets |
7321 | ||
7322 | @table @code | |
7323 | @item target @var{type} @var{parameters} | |
18fae2a8 | 7324 | Connects the @value{GDBN} host environment to a target machine or process. A |
70b88761 RP |
7325 | target is typically a protocol for talking to debugging facilities. You |
7326 | use the argument @var{type} to specify the type or protocol of the | |
7327 | target machine. | |
7328 | ||
7329 | Further @var{parameters} are interpreted by the target protocol, but | |
7330 | typically include things like device names or host names to connect | |
e251e767 | 7331 | with, process numbers, and baud rates. |
70b88761 RP |
7332 | |
7333 | The @code{target} command will not repeat if you press @key{RET} again | |
7334 | after executing the command. | |
7335 | ||
7336 | @item help target | |
7337 | @kindex help target | |
7338 | Displays the names of all targets available. To display targets | |
7339 | currently selected, use either @code{info target} or @code{info files} | |
29a2b744 | 7340 | (@pxref{Files, ,Commands to Specify Files}). |
70b88761 RP |
7341 | |
7342 | @item help target @var{name} | |
7343 | Describe a particular target, including any parameters necessary to | |
7344 | select it. | |
7345 | @end table | |
7346 | ||
c7cb8acb | 7347 | Here are some common targets (available, or not, depending on the GDB |
70b88761 RP |
7348 | configuration): |
7349 | ||
7350 | @table @code | |
7351 | @item target exec @var{prog} | |
7352 | @kindex target exec | |
7353 | An executable file. @samp{target exec @var{prog}} is the same as | |
7354 | @samp{exec-file @var{prog}}. | |
7355 | ||
7356 | @item target core @var{filename} | |
7357 | @kindex target core | |
7358 | A core dump file. @samp{target core @var{filename}} is the same as | |
7359 | @samp{core-file @var{filename}}. | |
7360 | ||
18fae2a8 | 7361 | @ifset REMOTESTUB |
70b88761 RP |
7362 | @item target remote @var{dev} |
7363 | @kindex target remote | |
c7cb8acb | 7364 | Remote serial target in GDB-specific protocol. The argument @var{dev} |
70b88761 | 7365 | specifies what serial device to use for the connection (e.g. |
1041a570 | 7366 | @file{/dev/ttya}). @xref{Remote, ,Remote Debugging}. |
18fae2a8 | 7367 | @end ifset |
70b88761 | 7368 | |
18fae2a8 | 7369 | @ifset AMDxxixK |
70b88761 RP |
7370 | @item target amd-eb @var{dev} @var{speed} @var{PROG} |
7371 | @kindex target amd-eb | |
7372 | @cindex AMD EB29K | |
7373 | Remote PC-resident AMD EB29K board, attached over serial lines. | |
7374 | @var{dev} is the serial device, as for @code{target remote}; | |
7375 | @var{speed} allows you to specify the linespeed; and @var{PROG} is the | |
7376 | name of the program to be debugged, as it appears to DOS on the PC. | |
ed447b95 | 7377 | @xref{EB29K Remote, ,@value{GDBN} with a remote EB29K}. |
77fe5411 | 7378 | |
18fae2a8 RP |
7379 | @end ifset |
7380 | @ifset Hviii | |
c7cb8acb RP |
7381 | @item target hms |
7382 | @kindex target hms | |
7383 | A Hitachi H8/300 board, attached via serial line to your host. Use | |
7384 | special commands @code{device} and @code{speed} to control the serial | |
7385 | line and the communications speed used. @xref{Hitachi H8/300 | |
18fae2a8 | 7386 | Remote,,@value{GDBN} and the Hitachi H8/300}. |
c7cb8acb | 7387 | |
18fae2a8 RP |
7388 | @end ifset |
7389 | @ifset Icmlx | |
70b88761 RP |
7390 | @item target nindy @var{devicename} |
7391 | @kindex target nindy | |
7392 | An Intel 960 board controlled by a Nindy Monitor. @var{devicename} is | |
7393 | the name of the serial device to use for the connection, e.g. | |
ed447b95 | 7394 | @file{/dev/ttya}. @xref{i960-Nindy Remote, ,@value{GDBN} with a remote i960 (Nindy)}. |
70b88761 | 7395 | |
18fae2a8 RP |
7396 | @end ifset |
7397 | @ifset STmm | |
77fe5411 RP |
7398 | @item target st2000 @var{dev} @var{speed} |
7399 | @kindex target st2000 | |
7400 | A Tandem ST2000 phone switch, running Tandem's STDBUG protocol. @var{dev} | |
7401 | is the name of the device attached to the ST2000 serial line; | |
7402 | @var{speed} is the communication line speed. The arguments are not used | |
18fae2a8 RP |
7403 | if @value{GDBN} is configured to connect to the ST2000 using TCP or Telnet. |
7404 | @xref{ST2000 Remote,,@value{GDBN} with a Tandem ST2000}. | |
77fe5411 | 7405 | |
18fae2a8 RP |
7406 | @end ifset |
7407 | @ifset VXWORKS | |
70b88761 RP |
7408 | @item target vxworks @var{machinename} |
7409 | @kindex target vxworks | |
7410 | A VxWorks system, attached via TCP/IP. The argument @var{machinename} | |
7411 | is the target system's machine name or IP address. | |
18fae2a8 RP |
7412 | @xref{VxWorks Remote, ,@value{GDBN} and VxWorks}. |
7413 | @end ifset | |
70b88761 RP |
7414 | @end table |
7415 | ||
18fae2a8 RP |
7416 | @ifset GENERIC |
7417 | Different targets are available on different configurations of @value{GDBN}; your | |
70b88761 | 7418 | configuration may have more or fewer targets. |
18fae2a8 | 7419 | @end ifset |
70b88761 | 7420 | |
4eb4cf57 | 7421 | @node Remote |
70b88761 RP |
7422 | @section Remote Debugging |
7423 | @cindex remote debugging | |
7424 | ||
29a2b744 | 7425 | If you are trying to debug a program running on a machine that cannot run |
c7cb8acb | 7426 | GDB in the usual way, it is often useful to use remote debugging. For |
70b88761 RP |
7427 | example, you might use remote debugging on an operating system kernel, or on |
7428 | a small system which does not have a general purpose operating system | |
e251e767 | 7429 | powerful enough to run a full-featured debugger. |
70b88761 | 7430 | |
c7cb8acb | 7431 | Some configurations of GDB have special serial or TCP/IP interfaces |
70b88761 | 7432 | to make this work with particular debugging targets. In addition, |
c7cb8acb | 7433 | GDB comes with a generic serial protocol (specific to GDB, but |
70b88761 RP |
7434 | not specific to any particular target system) which you can use if you |
7435 | write the remote stubs---the code that will run on the remote system to | |
c7cb8acb | 7436 | communicate with GDB. |
70b88761 | 7437 | |
70b88761 | 7438 | Other remote targets may be available in your |
c7cb8acb | 7439 | configuration of GDB; use @code{help targets} to list them. |
70b88761 | 7440 | |
18fae2a8 RP |
7441 | @ifset GENERIC |
7442 | @c Text on starting up GDB in various specific cases; it goes up front | |
7443 | @c in manuals configured for any of those particular situations, here | |
7444 | @c otherwise. | |
7445 | @ignore | |
7446 | @c original, intended form of this menu (pre-unfolding): | |
7447 | @menu | |
7448 | @ifset REMOTESTUB | |
7449 | * Remote Serial:: @value{GDBN} remote serial protocol | |
7450 | @end ifset | |
7451 | @ifset Icmlx | |
7452 | * i960-Nindy Remote:: @value{GDBN} with a remote i960 (Nindy) | |
7453 | @end ifset | |
7454 | @ifset AMDxxixK | |
7455 | * EB29K Remote:: @value{GDBN} with a remote EB29K | |
7456 | @end ifset | |
7457 | @ifset VXWORKS | |
7458 | * VxWorks Remote:: @value{GDBN} and VxWorks | |
7459 | @end ifset | |
7460 | @ifset STmm | |
7461 | * ST2000 Remote:: @value{GDBN} with a Tandem ST2000 | |
7462 | @end ifset | |
7463 | @ifset Hviii | |
7464 | * Hitachi H8/300 Remote:: @value{GDBN} and the Hitachi H8/300 | |
7465 | @end ifset | |
7466 | @ifset ZviiiK | |
7467 | * Z8000 Simulator:: @value{GDBN} and its Zilog Z8000 Simulator | |
7468 | @end ifset | |
7469 | @end menu | |
7470 | @end ignore | |
7471 | ||
7472 | @c Unfolded menus: | |
7473 | @c add as configs require, while unfolding remains necessary. | |
7474 | @c | |
7475 | @c All target details: | |
1041a570 | 7476 | @menu |
18fae2a8 RP |
7477 | * Remote Serial:: @value{GDBN} remote serial protocol |
7478 | * i960-Nindy Remote:: @value{GDBN} with a remote i960 (Nindy) | |
7479 | * EB29K Remote:: @value{GDBN} with a remote EB29K | |
7480 | * VxWorks Remote:: @value{GDBN} and VxWorks | |
7481 | * ST2000 Remote:: @value{GDBN} with a Tandem ST2000 | |
7482 | * Hitachi H8/300 Remote:: @value{GDBN} and the Hitachi H8/300 | |
7483 | * Z8000 Simulator:: @value{GDBN} and its Zilog Z8000 Simulator | |
1041a570 | 7484 | @end menu |
70b88761 | 7485 | |
18fae2a8 RP |
7486 | @include gdbinv-s.texi |
7487 | @end ifset | |
7488 | ||
7489 | @node Controlling GDB | |
7490 | @chapter Controlling @value{GDBN} | |
70b88761 | 7491 | |
18fae2a8 RP |
7492 | You can alter many aspects of @value{GDBN}'s interaction with you by using |
7493 | the @code{set} command. For commands controlling how @value{GDBN} displays | |
1041a570 | 7494 | data, @pxref{Print Settings, ,Print Settings}; other settings are described here. |
70b88761 RP |
7495 | |
7496 | @menu | |
b80282d5 | 7497 | * Prompt:: Prompt |
ed447b95 RP |
7498 | * Editing:: Command editing |
7499 | * History:: Command history | |
7500 | * Screen Size:: Screen size | |
b80282d5 | 7501 | * Numbers:: Numbers |
ed447b95 | 7502 | * Messages/Warnings:: Optional warnings and messages |
70b88761 RP |
7503 | @end menu |
7504 | ||
4eb4cf57 | 7505 | @node Prompt |
70b88761 RP |
7506 | @section Prompt |
7507 | @cindex prompt | |
1041a570 | 7508 | |
18fae2a8 RP |
7509 | @value{GDBN} indicates its readiness to read a command by printing a string |
7510 | called the @dfn{prompt}. This string is normally @samp{(@value{GDBP})}. You | |
70b88761 | 7511 | can change the prompt string with the @code{set prompt} command. For |
18fae2a8 RP |
7512 | instance, when debugging @value{GDBN} with @value{GDBN}, it is useful to change |
7513 | the prompt in one of the @value{GDBN}s so that you can always tell which | |
70b88761 RP |
7514 | one you are talking to. |
7515 | ||
7516 | @table @code | |
7517 | @item set prompt @var{newprompt} | |
7518 | @kindex set prompt | |
18fae2a8 | 7519 | Directs @value{GDBN} to use @var{newprompt} as its prompt string henceforth. |
70b88761 RP |
7520 | @kindex show prompt |
7521 | @item show prompt | |
7522 | Prints a line of the form: @samp{Gdb's prompt is: @var{your-prompt}} | |
7523 | @end table | |
7524 | ||
4eb4cf57 | 7525 | @node Editing |
70b88761 RP |
7526 | @section Command Editing |
7527 | @cindex readline | |
7528 | @cindex command line editing | |
1041a570 | 7529 | |
18fae2a8 | 7530 | @value{GDBN} reads its input commands via the @dfn{readline} interface. This |
70b88761 RP |
7531 | GNU library provides consistent behavior for programs which provide a |
7532 | command line interface to the user. Advantages are @code{emacs}-style | |
7533 | or @code{vi}-style inline editing of commands, @code{csh}-like history | |
7534 | substitution, and a storage and recall of command history across | |
7535 | debugging sessions. | |
7536 | ||
18fae2a8 | 7537 | You may control the behavior of command line editing in @value{GDBN} with the |
e251e767 | 7538 | command @code{set}. |
70b88761 RP |
7539 | |
7540 | @table @code | |
7541 | @kindex set editing | |
7542 | @cindex editing | |
7543 | @item set editing | |
7544 | @itemx set editing on | |
7545 | Enable command line editing (enabled by default). | |
7546 | ||
7547 | @item set editing off | |
7548 | Disable command line editing. | |
7549 | ||
7550 | @kindex show editing | |
7551 | @item show editing | |
7552 | Show whether command line editing is enabled. | |
7553 | @end table | |
7554 | ||
4eb4cf57 | 7555 | @node History |
ed447b95 RP |
7556 | @section Command history |
7557 | ||
7558 | @value{GDBN} can keep track of the commands you type during your | |
7559 | debugging sessions, so that you can be certain of precisely what | |
7560 | happened. Use these commands to manage the @value{GDBN} command | |
7561 | history facility. | |
1041a570 | 7562 | |
70b88761 RP |
7563 | @table @code |
7564 | @cindex history substitution | |
7565 | @cindex history file | |
7566 | @kindex set history filename | |
7567 | @item set history filename @var{fname} | |
18fae2a8 RP |
7568 | Set the name of the @value{GDBN} command history file to @var{fname}. This is |
7569 | the file from which @value{GDBN} will read an initial command history | |
70b88761 RP |
7570 | list or to which it will write this list when it exits. This list is |
7571 | accessed through history expansion or through the history | |
7572 | command editing characters listed below. This file defaults to the | |
7573 | value of the environment variable @code{GDBHISTFILE}, or to | |
7574 | @file{./.gdb_history} if this variable is not set. | |
7575 | ||
7576 | @cindex history save | |
7577 | @kindex set history save | |
7578 | @item set history save | |
7579 | @itemx set history save on | |
7580 | Record command history in a file, whose name may be specified with the | |
7581 | @code{set history filename} command. By default, this option is disabled. | |
7582 | ||
7583 | @item set history save off | |
7584 | Stop recording command history in a file. | |
7585 | ||
7586 | @cindex history size | |
7587 | @kindex set history size | |
7588 | @item set history size @var{size} | |
18fae2a8 | 7589 | Set the number of commands which @value{GDBN} will keep in its history list. |
70b88761 RP |
7590 | This defaults to the value of the environment variable |
7591 | @code{HISTSIZE}, or to 256 if this variable is not set. | |
7592 | @end table | |
7593 | ||
7594 | @cindex history expansion | |
7595 | History expansion assigns special meaning to the character @kbd{!}. | |
ed447b95 | 7596 | @ifset have-readline-appendices |
1041a570 | 7597 | @xref{Event Designators}. |
ed447b95 RP |
7598 | @end ifset |
7599 | ||
70b88761 RP |
7600 | Since @kbd{!} is also the logical not operator in C, history expansion |
7601 | is off by default. If you decide to enable history expansion with the | |
7602 | @code{set history expansion on} command, you may sometimes need to | |
7603 | follow @kbd{!} (when it is used as logical not, in an expression) with | |
7604 | a space or a tab to prevent it from being expanded. The readline | |
7605 | history facilities will not attempt substitution on the strings | |
7606 | @kbd{!=} and @kbd{!(}, even when history expansion is enabled. | |
7607 | ||
7608 | The commands to control history expansion are: | |
7609 | ||
7610 | @table @code | |
7611 | ||
7612 | @kindex set history expansion | |
7613 | @item set history expansion on | |
7614 | @itemx set history expansion | |
7615 | Enable history expansion. History expansion is off by default. | |
7616 | ||
7617 | @item set history expansion off | |
7618 | Disable history expansion. | |
7619 | ||
7620 | The readline code comes with more complete documentation of | |
7621 | editing and history expansion features. Users unfamiliar with @code{emacs} | |
e251e767 | 7622 | or @code{vi} may wish to read it. |
ed447b95 | 7623 | @ifset have-readline-appendices |
70b88761 | 7624 | @xref{Command Line Editing}. |
ed447b95 | 7625 | @end ifset |
70b88761 RP |
7626 | |
7627 | @c @group | |
7628 | @kindex show history | |
7629 | @item show history | |
7630 | @itemx show history filename | |
7631 | @itemx show history save | |
7632 | @itemx show history size | |
7633 | @itemx show history expansion | |
18fae2a8 | 7634 | These commands display the state of the @value{GDBN} history parameters. |
70b88761 RP |
7635 | @code{show history} by itself displays all four states. |
7636 | @c @end group | |
70b88761 RP |
7637 | @end table |
7638 | ||
7639 | @table @code | |
7640 | @kindex show commands | |
7641 | @item show commands | |
7642 | Display the last ten commands in the command history. | |
7643 | ||
7644 | @item show commands @var{n} | |
7645 | Print ten commands centered on command number @var{n}. | |
7646 | ||
7647 | @item show commands + | |
7648 | Print ten commands just after the commands last printed. | |
70b88761 RP |
7649 | @end table |
7650 | ||
4eb4cf57 | 7651 | @node Screen Size |
70b88761 RP |
7652 | @section Screen Size |
7653 | @cindex size of screen | |
7654 | @cindex pauses in output | |
1041a570 | 7655 | |
18fae2a8 RP |
7656 | Certain commands to @value{GDBN} may produce large amounts of information |
7657 | output to the screen. To help you read all of it, @value{GDBN} pauses and | |
70b88761 | 7658 | asks you for input at the end of each page of output. Type @key{RET} |
18fae2a8 | 7659 | when you want to continue the output. @value{GDBN} also uses the screen |
70b88761 RP |
7660 | width setting to determine when to wrap lines of output. Depending on |
7661 | what is being printed, it tries to break the line at a readable place, | |
7662 | rather than simply letting it overflow onto the following line. | |
7663 | ||
18fae2a8 | 7664 | Normally @value{GDBN} knows the size of the screen from the termcap data base |
70b88761 RP |
7665 | together with the value of the @code{TERM} environment variable and the |
7666 | @code{stty rows} and @code{stty cols} settings. If this is not correct, | |
7667 | you can override it with the @code{set height} and @code{set | |
7668 | width} commands: | |
7669 | ||
7670 | @table @code | |
7671 | @item set height @var{lpp} | |
7672 | @itemx show height | |
7673 | @itemx set width @var{cpl} | |
7674 | @itemx show width | |
7675 | @kindex set height | |
7676 | @kindex set width | |
7677 | @kindex show width | |
7678 | @kindex show height | |
7679 | These @code{set} commands specify a screen height of @var{lpp} lines and | |
7680 | a screen width of @var{cpl} characters. The associated @code{show} | |
7681 | commands display the current settings. | |
7682 | ||
18fae2a8 | 7683 | If you specify a height of zero lines, @value{GDBN} will not pause during output |
70b88761 RP |
7684 | no matter how long the output is. This is useful if output is to a file |
7685 | or to an editor buffer. | |
7686 | @end table | |
7687 | ||
4eb4cf57 | 7688 | @node Numbers |
70b88761 RP |
7689 | @section Numbers |
7690 | @cindex number representation | |
7691 | @cindex entering numbers | |
1041a570 | 7692 | |
18fae2a8 | 7693 | You can always enter numbers in octal, decimal, or hexadecimal in @value{GDBN} by |
70b88761 RP |
7694 | the usual conventions: octal numbers begin with @samp{0}, decimal |
7695 | numbers end with @samp{.}, and hexadecimal numbers begin with @samp{0x}. | |
7696 | Numbers that begin with none of these are, by default, entered in base | |
7697 | 10; likewise, the default display for numbers---when no particular | |
7698 | format is specified---is base 10. You can change the default base for | |
7699 | both input and output with the @code{set radix} command. | |
7700 | ||
7701 | @table @code | |
7702 | @kindex set radix | |
7703 | @item set radix @var{base} | |
7704 | Set the default base for numeric input and display. Supported choices | |
c2bbbb22 | 7705 | for @var{base} are decimal 2, 8, 10, 16. @var{base} must itself be |
70b88761 RP |
7706 | specified either unambiguously or using the current default radix; for |
7707 | example, any of | |
7708 | ||
7709 | @example | |
c2bbbb22 | 7710 | set radix 1010 |
70b88761 RP |
7711 | set radix 012 |
7712 | set radix 10. | |
7713 | set radix 0xa | |
7714 | @end example | |
7715 | ||
7716 | @noindent | |
7717 | will set the base to decimal. On the other hand, @samp{set radix 10} | |
7718 | will leave the radix unchanged no matter what it was. | |
7719 | ||
7720 | @kindex show radix | |
7721 | @item show radix | |
7722 | Display the current default base for numeric input and display. | |
70b88761 RP |
7723 | @end table |
7724 | ||
4eb4cf57 | 7725 | @node Messages/Warnings |
70b88761 | 7726 | @section Optional Warnings and Messages |
1041a570 | 7727 | |
18fae2a8 | 7728 | By default, @value{GDBN} is silent about its inner workings. If you are running |
70b88761 | 7729 | on a slow machine, you may want to use the @code{set verbose} command. |
18fae2a8 | 7730 | It will make @value{GDBN} tell you when it does a lengthy internal operation, so |
1041a570 | 7731 | you will not think it has crashed. |
70b88761 | 7732 | |
1041a570 | 7733 | Currently, the messages controlled by @code{set verbose} are those |
d48da190 RP |
7734 | which announce that the symbol table for a source file is being read; |
7735 | see @code{symbol-file} in @ref{Files, ,Commands to Specify Files}. | |
70b88761 RP |
7736 | |
7737 | @table @code | |
7738 | @kindex set verbose | |
7739 | @item set verbose on | |
18fae2a8 | 7740 | Enables @value{GDBN}'s output of certain informational messages. |
70b88761 RP |
7741 | |
7742 | @item set verbose off | |
18fae2a8 | 7743 | Disables @value{GDBN}'s output of certain informational messages. |
70b88761 RP |
7744 | |
7745 | @kindex show verbose | |
7746 | @item show verbose | |
7747 | Displays whether @code{set verbose} is on or off. | |
7748 | @end table | |
7749 | ||
18fae2a8 | 7750 | By default, if @value{GDBN} encounters bugs in the symbol table of an object |
b80282d5 | 7751 | file, it is silent; but if you are debugging a compiler, you may find |
1041a570 | 7752 | this information useful (@pxref{Symbol Errors, ,Errors Reading Symbol Files}). |
70b88761 RP |
7753 | |
7754 | @table @code | |
7755 | @kindex set complaints | |
7756 | @item set complaints @var{limit} | |
18fae2a8 | 7757 | Permits @value{GDBN} to output @var{limit} complaints about each type of unusual |
70b88761 RP |
7758 | symbols before becoming silent about the problem. Set @var{limit} to |
7759 | zero to suppress all complaints; set it to a large number to prevent | |
7760 | complaints from being suppressed. | |
7761 | ||
7762 | @kindex show complaints | |
7763 | @item show complaints | |
18fae2a8 | 7764 | Displays how many symbol complaints @value{GDBN} is permitted to produce. |
70b88761 RP |
7765 | @end table |
7766 | ||
18fae2a8 | 7767 | By default, @value{GDBN} is cautious, and asks what sometimes seems to be a |
70b88761 RP |
7768 | lot of stupid questions to confirm certain commands. For example, if |
7769 | you try to run a program which is already running: | |
1041a570 | 7770 | |
70b88761 | 7771 | @example |
18fae2a8 | 7772 | (@value{GDBP}) run |
70b88761 | 7773 | The program being debugged has been started already. |
e251e767 | 7774 | Start it from the beginning? (y or n) |
70b88761 RP |
7775 | @end example |
7776 | ||
29a2b744 | 7777 | If you are willing to unflinchingly face the consequences of your own |
70b88761 RP |
7778 | commands, you can disable this ``feature'': |
7779 | ||
7780 | @table @code | |
7781 | @kindex set confirm | |
7782 | @cindex flinching | |
7783 | @cindex confirmation | |
7784 | @cindex stupid questions | |
7785 | @item set confirm off | |
7786 | Disables confirmation requests. | |
7787 | ||
7788 | @item set confirm on | |
7789 | Enables confirmation requests (the default). | |
7790 | ||
7791 | @item show confirm | |
7792 | @kindex show confirm | |
7793 | Displays state of confirmation requests. | |
7794 | @end table | |
7795 | ||
29a2b744 | 7796 | @c FIXME this does not really belong here. But where *does* it belong? |
b80282d5 RP |
7797 | @cindex reloading symbols |
7798 | Some systems allow individual object files that make up your program to | |
7799 | be replaced without stopping and restarting your program. | |
18fae2a8 | 7800 | @ifset VXWORKS |
b80282d5 RP |
7801 | For example, in VxWorks you can simply recompile a defective object file |
7802 | and keep on running. | |
18fae2a8 RP |
7803 | @end ifset |
7804 | If you are running on one of these systems, you can allow @value{GDBN} to | |
1041a570 RP |
7805 | reload the symbols for automatically relinked modules: |
7806 | ||
b80282d5 RP |
7807 | @table @code |
7808 | @kindex set symbol-reloading | |
7809 | @item set symbol-reloading on | |
7810 | Replace symbol definitions for the corresponding source file when an | |
7811 | object file with a particular name is seen again. | |
7812 | ||
7813 | @item set symbol-reloading off | |
1041a570 | 7814 | Do not replace symbol definitions when re-encountering object files of |
29a2b744 | 7815 | the same name. This is the default state; if you are not running on a |
b80282d5 | 7816 | system that permits automatically relinking modules, you should leave |
18fae2a8 | 7817 | @code{symbol-reloading} off, since otherwise @value{GDBN} may discard symbols |
b80282d5 RP |
7818 | when linking large programs, that may contain several modules (from |
7819 | different directories or libraries) with the same name. | |
7820 | ||
7821 | @item show symbol-reloading | |
7822 | Show the current @code{on} or @code{off} setting. | |
7823 | @end table | |
7824 | ||
4eb4cf57 | 7825 | @node Sequences |
70b88761 RP |
7826 | @chapter Canned Sequences of Commands |
7827 | ||
29a2b744 | 7828 | Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint |
18fae2a8 | 7829 | Command Lists}), @value{GDBN} provides two ways to store sequences of commands |
1041a570 | 7830 | for execution as a unit: user-defined commands and command files. |
70b88761 RP |
7831 | |
7832 | @menu | |
ed447b95 RP |
7833 | * Define:: User-defined commands |
7834 | * Hooks:: User-defined command hooks | |
7835 | * Command Files:: Command files | |
7836 | * Output:: Commands for controlled output | |
70b88761 RP |
7837 | @end menu |
7838 | ||
4eb4cf57 | 7839 | @node Define |
ed447b95 | 7840 | @section User-defined commands |
70b88761 RP |
7841 | |
7842 | @cindex user-defined command | |
18fae2a8 | 7843 | A @dfn{user-defined command} is a sequence of @value{GDBN} commands to which you |
70b88761 RP |
7844 | assign a new name as a command. This is done with the @code{define} |
7845 | command. | |
7846 | ||
7847 | @table @code | |
7848 | @item define @var{commandname} | |
7849 | @kindex define | |
7850 | Define a command named @var{commandname}. If there is already a command | |
7851 | by that name, you are asked to confirm that you want to redefine it. | |
7852 | ||
18fae2a8 | 7853 | The definition of the command is made up of other @value{GDBN} command lines, |
70b88761 RP |
7854 | which are given following the @code{define} command. The end of these |
7855 | commands is marked by a line containing @code{end}. | |
7856 | ||
7857 | @item document @var{commandname} | |
7858 | @kindex document | |
7859 | Give documentation to the user-defined command @var{commandname}. The | |
7860 | command @var{commandname} must already be defined. This command reads | |
7861 | lines of documentation just as @code{define} reads the lines of the | |
7862 | command definition, ending with @code{end}. After the @code{document} | |
7863 | command is finished, @code{help} on command @var{commandname} will print | |
7864 | the documentation you have specified. | |
7865 | ||
7866 | You may use the @code{document} command again to change the | |
7867 | documentation of a command. Redefining the command with @code{define} | |
7868 | does not change the documentation. | |
7869 | ||
7870 | @item help user-defined | |
7871 | @kindex help user-defined | |
7872 | List all user-defined commands, with the first line of the documentation | |
7873 | (if any) for each. | |
7874 | ||
4768ba62 JG |
7875 | @item show user |
7876 | @itemx show user @var{commandname} | |
7877 | @kindex show user | |
18fae2a8 | 7878 | Display the @value{GDBN} commands used to define @var{commandname} (but not its |
70b88761 RP |
7879 | documentation). If no @var{commandname} is given, display the |
7880 | definitions for all user-defined commands. | |
7881 | @end table | |
7882 | ||
7883 | User-defined commands do not take arguments. When they are executed, the | |
7884 | commands of the definition are not printed. An error in any command | |
7885 | stops execution of the user-defined command. | |
7886 | ||
7887 | Commands that would ask for confirmation if used interactively proceed | |
18fae2a8 | 7888 | without asking when used inside a user-defined command. Many @value{GDBN} commands |
70b88761 RP |
7889 | that normally print messages to say what they are doing omit the messages |
7890 | when used in a user-defined command. | |
7891 | ||
35a15d60 JG |
7892 | @node Hooks |
7893 | @section User-Defined Command Hooks | |
7894 | @cindex command files | |
7895 | ||
7896 | You may define @emph{hooks}, which are a special kind of user-defined | |
7897 | command. Whenever you run the command @samp{foo}, if the user-defined | |
7898 | command @samp{hook-foo} exists, it is executed (with no arguments) | |
7899 | before that command. | |
7900 | ||
7901 | In addition, a pseudo-command, @samp{stop} exists. Hooking this command | |
7902 | will cause your hook to be executed every time execution stops in the | |
7903 | inferior program, before breakpoint commands are run, displays are | |
7904 | printed, or the stack frame is printed. | |
7905 | ||
7906 | For example, to cause @code{SIGALRM} signals to be ignored while | |
7907 | single-stepping, but cause them to be resumed during normal execution, | |
7908 | you could do: | |
7909 | ||
7910 | @example | |
7911 | define hook-stop | |
7912 | handle SIGALRM nopass | |
7913 | end | |
7914 | ||
7915 | define hook-run | |
7916 | handle SIGALRM pass | |
7917 | end | |
7918 | ||
7919 | define hook-continue | |
7920 | handle SIGLARM pass | |
7921 | end | |
7922 | @end example | |
7923 | ||
7924 | Any single-word command in GDB can be hooked. Aliases for other commands | |
7925 | cannot be hooked (you should hook the basic command name, e.g. @code{backtrace} | |
7926 | rather than @code{bt}). If an error occurs during the execution of your | |
7927 | hook, execution of GDB commands stops and you are returned to the GDB | |
7928 | prompt (before the command that you actually typed had a chance to run). | |
7929 | ||
7930 | If you try to define a hook which doesn't match any known command, you | |
7931 | will get a warning from the @code{define} command. | |
7932 | ||
4eb4cf57 | 7933 | @node Command Files |
70b88761 RP |
7934 | @section Command Files |
7935 | ||
7936 | @cindex command files | |
18fae2a8 | 7937 | A command file for @value{GDBN} is a file of lines that are @value{GDBN} commands. Comments |
70b88761 RP |
7938 | (lines starting with @kbd{#}) may also be included. An empty line in a |
7939 | command file does nothing; it does not mean to repeat the last command, as | |
7940 | it would from the terminal. | |
7941 | ||
7942 | @cindex init file | |
18fae2a8 RP |
7943 | @cindex @file{@value{GDBINIT}} |
7944 | When you start @value{GDBN}, it automatically executes commands from its | |
7945 | @dfn{init files}. These are files named @file{@value{GDBINIT}}. @value{GDBN} reads | |
1041a570 RP |
7946 | the init file (if any) in your home directory and then the init file |
7947 | (if any) in the current working directory. (The init files are not | |
7948 | executed if you use the @samp{-nx} option; @pxref{Mode Options, | |
7949 | ,Choosing Modes}.) You can also request the execution of a command | |
7950 | file with the @code{source} command: | |
70b88761 RP |
7951 | |
7952 | @table @code | |
7953 | @item source @var{filename} | |
7954 | @kindex source | |
7955 | Execute the command file @var{filename}. | |
7956 | @end table | |
7957 | ||
7958 | The lines in a command file are executed sequentially. They are not | |
7959 | printed as they are executed. An error in any command terminates execution | |
7960 | of the command file. | |
7961 | ||
7962 | Commands that would ask for confirmation if used interactively proceed | |
18fae2a8 | 7963 | without asking when used in a command file. Many @value{GDBN} commands that |
70b88761 RP |
7964 | normally print messages to say what they are doing omit the messages |
7965 | when called from command files. | |
7966 | ||
4eb4cf57 | 7967 | @node Output |
70b88761 RP |
7968 | @section Commands for Controlled Output |
7969 | ||
7970 | During the execution of a command file or a user-defined command, normal | |
18fae2a8 | 7971 | @value{GDBN} output is suppressed; the only output that appears is what is |
70b88761 RP |
7972 | explicitly printed by the commands in the definition. This section |
7973 | describes three commands useful for generating exactly the output you | |
7974 | want. | |
7975 | ||
7976 | @table @code | |
7977 | @item echo @var{text} | |
7978 | @kindex echo | |
29a2b744 RP |
7979 | @c I do not consider backslash-space a standard C escape sequence |
7980 | @c because it is not in ANSI. | |
1041a570 RP |
7981 | Print @var{text}. Nonprinting characters can be included in |
7982 | @var{text} using C escape sequences, such as @samp{\n} to print a | |
7983 | newline. @strong{No newline will be printed unless you specify one.} | |
7984 | In addition to the standard C escape sequences, a backslash followed | |
ed447b95 | 7985 | by a space stands for a space. This is useful for displaying a |
1041a570 RP |
7986 | string with spaces at the beginning or the end, since leading and |
7987 | trailing spaces are otherwise trimmed from all arguments. | |
7988 | To print @samp{@w{ }and foo =@w{ }}, use the command | |
7989 | @samp{echo \@w{ }and foo = \@w{ }}. | |
70b88761 RP |
7990 | |
7991 | A backslash at the end of @var{text} can be used, as in C, to continue | |
7992 | the command onto subsequent lines. For example, | |
7993 | ||
7994 | @example | |
7995 | echo This is some text\n\ | |
7996 | which is continued\n\ | |
7997 | onto several lines.\n | |
7998 | @end example | |
7999 | ||
8000 | produces the same output as | |
8001 | ||
8002 | @example | |
8003 | echo This is some text\n | |
8004 | echo which is continued\n | |
8005 | echo onto several lines.\n | |
8006 | @end example | |
8007 | ||
8008 | @item output @var{expression} | |
8009 | @kindex output | |
8010 | Print the value of @var{expression} and nothing but that value: no | |
8011 | newlines, no @samp{$@var{nn} = }. The value is not entered in the | |
1041a570 | 8012 | value history either. @xref{Expressions, ,Expressions}, for more information on |
e251e767 | 8013 | expressions. |
70b88761 RP |
8014 | |
8015 | @item output/@var{fmt} @var{expression} | |
8016 | Print the value of @var{expression} in format @var{fmt}. You can use | |
ed447b95 RP |
8017 | the same formats as for @code{print}. @xref{Output Formats,,Output |
8018 | formats}, for more information. | |
70b88761 RP |
8019 | |
8020 | @item printf @var{string}, @var{expressions}@dots{} | |
8021 | @kindex printf | |
8022 | Print the values of the @var{expressions} under the control of | |
8023 | @var{string}. The @var{expressions} are separated by commas and may | |
8024 | be either numbers or pointers. Their values are printed as specified | |
29a2b744 | 8025 | by @var{string}, exactly as if your program were to execute |
70b88761 RP |
8026 | |
8027 | @example | |
8028 | printf (@var{string}, @var{expressions}@dots{}); | |
8029 | @end example | |
8030 | ||
8031 | For example, you can print two values in hex like this: | |
8032 | ||
0fd24984 | 8033 | @smallexample |
70b88761 | 8034 | printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo |
0fd24984 | 8035 | @end smallexample |
70b88761 RP |
8036 | |
8037 | The only backslash-escape sequences that you can use in the format | |
8038 | string are the simple ones that consist of backslash followed by a | |
8039 | letter. | |
8040 | @end table | |
8041 | ||
18fae2a8 | 8042 | @ifclear DOSHOST |
4eb4cf57 | 8043 | @node Emacs |
18fae2a8 | 8044 | @chapter Using @value{GDBN} under GNU Emacs |
70b88761 RP |
8045 | |
8046 | @cindex emacs | |
8047 | A special interface allows you to use GNU Emacs to view (and | |
8048 | edit) the source files for the program you are debugging with | |
18fae2a8 | 8049 | @value{GDBN}. |
70b88761 RP |
8050 | |
8051 | To use this interface, use the command @kbd{M-x gdb} in Emacs. Give the | |
8052 | executable file you want to debug as an argument. This command starts | |
18fae2a8 | 8053 | @value{GDBN} as a subprocess of Emacs, with input and output through a newly |
70b88761 RP |
8054 | created Emacs buffer. |
8055 | ||
18fae2a8 | 8056 | Using @value{GDBN} under Emacs is just like using @value{GDBN} normally except for two |
70b88761 RP |
8057 | things: |
8058 | ||
8059 | @itemize @bullet | |
8060 | @item | |
e251e767 | 8061 | All ``terminal'' input and output goes through the Emacs buffer. |
70b88761 RP |
8062 | @end itemize |
8063 | ||
18fae2a8 | 8064 | This applies both to @value{GDBN} commands and their output, and to the input |
70b88761 RP |
8065 | and output done by the program you are debugging. |
8066 | ||
8067 | This is useful because it means that you can copy the text of previous | |
8068 | commands and input them again; you can even use parts of the output | |
8069 | in this way. | |
8070 | ||
3d3ab540 RP |
8071 | All the facilities of Emacs' Shell mode are available for interacting |
8072 | with your program. In particular, you can send signals the usual | |
8073 | way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a | |
8074 | stop. | |
70b88761 RP |
8075 | |
8076 | @itemize @bullet | |
8077 | @item | |
18fae2a8 | 8078 | @value{GDBN} displays source code through Emacs. |
70b88761 RP |
8079 | @end itemize |
8080 | ||
18fae2a8 RP |
8081 | Each time @value{GDBN} displays a stack frame, Emacs automatically finds the |
8082 | source file for that frame and puts an arrow (@samp{=>}) at the | |
70b88761 | 8083 | left margin of the current line. Emacs uses a separate buffer for |
18fae2a8 | 8084 | source display, and splits the window to show both your @value{GDBN} session |
70b88761 RP |
8085 | and the source. |
8086 | ||
18fae2a8 | 8087 | Explicit @value{GDBN} @code{list} or search commands still produce output as |
70b88761 RP |
8088 | usual, but you probably will have no reason to use them. |
8089 | ||
8090 | @quotation | |
8091 | @emph{Warning:} If the directory where your program resides is not your | |
8092 | current directory, it can be easy to confuse Emacs about the location of | |
8093 | the source files, in which case the auxiliary display buffer will not | |
18fae2a8 RP |
8094 | appear to show your source. @value{GDBN} can find programs by searching your |
8095 | environment's @code{PATH} variable, so the @value{GDBN} input and output | |
29a2b744 | 8096 | session will proceed normally; but Emacs does not get enough information |
18fae2a8 RP |
8097 | back from @value{GDBN} to locate the source files in this situation. To |
8098 | avoid this problem, either start @value{GDBN} mode from the directory where | |
70b88761 RP |
8099 | your program resides, or specify a full path name when prompted for the |
8100 | @kbd{M-x gdb} argument. | |
8101 | ||
18fae2a8 | 8102 | A similar confusion can result if you use the @value{GDBN} @code{file} command to |
70b88761 | 8103 | switch to debugging a program in some other location, from an existing |
18fae2a8 | 8104 | @value{GDBN} buffer in Emacs. |
70b88761 RP |
8105 | @end quotation |
8106 | ||
8107 | By default, @kbd{M-x gdb} calls the program called @file{gdb}. If | |
18fae2a8 | 8108 | you need to call @value{GDBN} by a different name (for example, if you keep |
70b88761 RP |
8109 | several configurations around, with different names) you can set the |
8110 | Emacs variable @code{gdb-command-name}; for example, | |
1041a570 | 8111 | |
70b88761 RP |
8112 | @example |
8113 | (setq gdb-command-name "mygdb") | |
8114 | @end example | |
1041a570 | 8115 | |
70b88761 RP |
8116 | @noindent |
8117 | (preceded by @kbd{ESC ESC}, or typed in the @code{*scratch*} buffer, or | |
8118 | in your @file{.emacs} file) will make Emacs call the program named | |
8119 | ``@code{mygdb}'' instead. | |
8120 | ||
18fae2a8 | 8121 | In the @value{GDBN} I/O buffer, you can use these special Emacs commands in |
70b88761 RP |
8122 | addition to the standard Shell mode commands: |
8123 | ||
8124 | @table @kbd | |
8125 | @item C-h m | |
18fae2a8 | 8126 | Describe the features of Emacs' @value{GDBN} Mode. |
70b88761 RP |
8127 | |
8128 | @item M-s | |
18fae2a8 | 8129 | Execute to another source line, like the @value{GDBN} @code{step} command; also |
70b88761 RP |
8130 | update the display window to show the current file and location. |
8131 | ||
8132 | @item M-n | |
8133 | Execute to next source line in this function, skipping all function | |
18fae2a8 | 8134 | calls, like the @value{GDBN} @code{next} command. Then update the display window |
70b88761 RP |
8135 | to show the current file and location. |
8136 | ||
8137 | @item M-i | |
18fae2a8 | 8138 | Execute one instruction, like the @value{GDBN} @code{stepi} command; update |
70b88761 RP |
8139 | display window accordingly. |
8140 | ||
8141 | @item M-x gdb-nexti | |
18fae2a8 | 8142 | Execute to next instruction, using the @value{GDBN} @code{nexti} command; update |
70b88761 RP |
8143 | display window accordingly. |
8144 | ||
8145 | @item C-c C-f | |
18fae2a8 | 8146 | Execute until exit from the selected stack frame, like the @value{GDBN} |
70b88761 RP |
8147 | @code{finish} command. |
8148 | ||
8149 | @item M-c | |
18fae2a8 | 8150 | Continue execution of your program, like the @value{GDBN} @code{continue} |
1041a570 | 8151 | command. |
203eea5d RP |
8152 | |
8153 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-p}. | |
70b88761 RP |
8154 | |
8155 | @item M-u | |
8156 | Go up the number of frames indicated by the numeric argument | |
8157 | (@pxref{Arguments, , Numeric Arguments, emacs, The GNU Emacs Manual}), | |
18fae2a8 | 8158 | like the @value{GDBN} @code{up} command. |
203eea5d | 8159 | |
1041a570 | 8160 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-u}. |
70b88761 RP |
8161 | |
8162 | @item M-d | |
8163 | Go down the number of frames indicated by the numeric argument, like the | |
18fae2a8 | 8164 | @value{GDBN} @code{down} command. |
203eea5d RP |
8165 | |
8166 | @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-d}. | |
70b88761 RP |
8167 | |
8168 | @item C-x & | |
8169 | Read the number where the cursor is positioned, and insert it at the end | |
18fae2a8 | 8170 | of the @value{GDBN} I/O buffer. For example, if you wish to disassemble code |
70b88761 RP |
8171 | around an address that was displayed earlier, type @kbd{disassemble}; |
8172 | then move the cursor to the address display, and pick up the | |
e251e767 | 8173 | argument for @code{disassemble} by typing @kbd{C-x &}. |
70b88761 | 8174 | |
ed447b95 | 8175 | You can customize this further by defining elements of the list |
70b88761 RP |
8176 | @code{gdb-print-command}; once it is defined, you can format or |
8177 | otherwise process numbers picked up by @kbd{C-x &} before they are | |
c2bbbb22 | 8178 | inserted. A numeric argument to @kbd{C-x &} will both indicate that you |
70b88761 RP |
8179 | wish special formatting, and act as an index to pick an element of the |
8180 | list. If the list element is a string, the number to be inserted is | |
8181 | formatted using the Emacs function @code{format}; otherwise the number | |
8182 | is passed as an argument to the corresponding list element. | |
70b88761 RP |
8183 | @end table |
8184 | ||
8185 | In any source file, the Emacs command @kbd{C-x SPC} (@code{gdb-break}) | |
18fae2a8 | 8186 | tells @value{GDBN} to set a breakpoint on the source line point is on. |
70b88761 RP |
8187 | |
8188 | If you accidentally delete the source-display buffer, an easy way to get | |
18fae2a8 | 8189 | it back is to type the command @code{f} in the @value{GDBN} buffer, to |
70b88761 RP |
8190 | request a frame display; when you run under Emacs, this will recreate |
8191 | the source buffer if necessary to show you the context of the current | |
8192 | frame. | |
8193 | ||
8194 | The source files displayed in Emacs are in ordinary Emacs buffers | |
8195 | which are visiting the source files in the usual way. You can edit | |
18fae2a8 | 8196 | the files with these buffers if you wish; but keep in mind that @value{GDBN} |
70b88761 | 8197 | communicates with Emacs in terms of line numbers. If you add or |
18fae2a8 | 8198 | delete lines from the text, the line numbers that @value{GDBN} knows will cease |
ed447b95 | 8199 | to correspond properly with the code. |
70b88761 RP |
8200 | |
8201 | @c The following dropped because Epoch is nonstandard. Reactivate | |
8202 | @c if/when v19 does something similar. ---pesch@cygnus.com 19dec1990 | |
8203 | @ignore | |
e251e767 | 8204 | @kindex emacs epoch environment |
70b88761 RP |
8205 | @kindex epoch |
8206 | @kindex inspect | |
8207 | ||
8208 | Version 18 of Emacs has a built-in window system called the @code{epoch} | |
8209 | environment. Users of this environment can use a new command, | |
8210 | @code{inspect} which performs identically to @code{print} except that | |
8211 | each value is printed in its own window. | |
8212 | @end ignore | |
18fae2a8 | 8213 | @end ifclear |
70b88761 | 8214 | |
18fae2a8 | 8215 | @ifset LUCID |
4eb4cf57 | 8216 | @node Energize |
18fae2a8 | 8217 | @chapter Using @value{GDBN} with Energize |
6ca72cc6 RP |
8218 | |
8219 | @cindex Energize | |
8220 | The Energize Programming System is an integrated development environment | |
8221 | that includes a point-and-click interface to many programming tools. | |
18fae2a8 RP |
8222 | When you use @value{GDBN} in this environment, you can use the standard |
8223 | Energize graphical interface to drive @value{GDBN}; you can also, if you | |
8224 | choose, type @value{GDBN} commands as usual in a debugging window. Even if | |
6ca72cc6 | 8225 | you use the graphical interface, the debugging window (which uses Emacs, |
18fae2a8 | 8226 | and resembles the standard Emacs interface to @value{GDBN}) displays the |
6ca72cc6 RP |
8227 | equivalent commands, so that the history of your debugging session is |
8228 | properly reflected. | |
8229 | ||
18fae2a8 | 8230 | When Energize starts up a @value{GDBN} session, it uses one of the |
6ca72cc6 RP |
8231 | command-line options @samp{-energize} or @samp{-cadillac} (``cadillac'' |
8232 | is the name of the communications protocol used by the Energize system). | |
18fae2a8 | 8233 | This option makes @value{GDBN} run as one of the tools in the Energize Tool |
6ca72cc6 RP |
8234 | Set: it sends all output to the Energize kernel, and accept input from |
8235 | it as well. | |
8236 | ||
8237 | See the user manual for the Energize Programming System for | |
8238 | information on how to use the Energize graphical interface and the other | |
18fae2a8 | 8239 | development tools that Energize integrates with @value{GDBN}. |
6ca72cc6 | 8240 | |
18fae2a8 | 8241 | @end ifset |
4eb4cf57 | 8242 | |
18fae2a8 RP |
8243 | @node GDB Bugs |
8244 | @chapter Reporting Bugs in @value{GDBN} | |
ed447b95 RP |
8245 | @cindex bugs in @value{GDBN} |
8246 | @cindex reporting bugs in @value{GDBN} | |
70b88761 | 8247 | |
18fae2a8 | 8248 | Your bug reports play an essential role in making @value{GDBN} reliable. |
70b88761 RP |
8249 | |
8250 | Reporting a bug may help you by bringing a solution to your problem, or it | |
8251 | may not. But in any case the principal function of a bug report is to help | |
18fae2a8 RP |
8252 | the entire community by making the next version of @value{GDBN} work better. Bug |
8253 | reports are your contribution to the maintenance of @value{GDBN}. | |
70b88761 RP |
8254 | |
8255 | In order for a bug report to serve its purpose, you must include the | |
8256 | information that enables us to fix the bug. | |
8257 | ||
8258 | @menu | |
ed447b95 RP |
8259 | * Bug Criteria:: Have you found a bug? |
8260 | * Bug Reporting:: How to report bugs | |
70b88761 RP |
8261 | @end menu |
8262 | ||
4eb4cf57 | 8263 | @node Bug Criteria |
70b88761 | 8264 | @section Have You Found a Bug? |
ed447b95 | 8265 | @cindex bug criteria |
70b88761 RP |
8266 | |
8267 | If you are not sure whether you have found a bug, here are some guidelines: | |
8268 | ||
8269 | @itemize @bullet | |
8270 | @item | |
0f153e74 RP |
8271 | @cindex fatal signal |
8272 | @cindex core dump | |
70b88761 | 8273 | If the debugger gets a fatal signal, for any input whatever, that is a |
18fae2a8 | 8274 | @value{GDBN} bug. Reliable debuggers never crash. |
70b88761 RP |
8275 | |
8276 | @item | |
0f153e74 | 8277 | @cindex error on valid input |
18fae2a8 | 8278 | If @value{GDBN} produces an error message for valid input, that is a bug. |
70b88761 RP |
8279 | |
8280 | @item | |
ed447b95 | 8281 | @cindex invalid input |
18fae2a8 | 8282 | If @value{GDBN} does not produce an error message for invalid input, |
70b88761 RP |
8283 | that is a bug. However, you should note that your idea of |
8284 | ``invalid input'' might be our idea of ``an extension'' or ``support | |
8285 | for traditional practice''. | |
8286 | ||
8287 | @item | |
8288 | If you are an experienced user of debugging tools, your suggestions | |
18fae2a8 | 8289 | for improvement of @value{GDBN} are welcome in any case. |
70b88761 RP |
8290 | @end itemize |
8291 | ||
4eb4cf57 | 8292 | @node Bug Reporting |
70b88761 | 8293 | @section How to Report Bugs |
0f153e74 | 8294 | @cindex bug reports |
18fae2a8 | 8295 | @cindex @value{GDBN} bugs, reporting |
70b88761 RP |
8296 | |
8297 | A number of companies and individuals offer support for GNU products. | |
18fae2a8 | 8298 | If you obtained @value{GDBN} from a support organization, we recommend you |
e251e767 | 8299 | contact that organization first. |
70b88761 | 8300 | |
ed447b95 RP |
8301 | You can find contact information for many support companies and |
8302 | individuals in the file @file{etc/SERVICE} in the GNU Emacs | |
8303 | distribution. | |
70b88761 | 8304 | |
18fae2a8 | 8305 | In any event, we also recommend that you send bug reports for @value{GDBN} to one |
70b88761 RP |
8306 | of these addresses: |
8307 | ||
8308 | @example | |
8309 | bug-gdb@@prep.ai.mit.edu | |
8310 | @{ucbvax|mit-eddie|uunet@}!prep.ai.mit.edu!bug-gdb | |
8311 | @end example | |
8312 | ||
8313 | @strong{Do not send bug reports to @samp{info-gdb}, or to | |
18fae2a8 | 8314 | @samp{help-gdb}, or to any newsgroups.} Most users of @value{GDBN} do not want to |
70b88761 RP |
8315 | receive bug reports. Those that do, have arranged to receive @samp{bug-gdb}. |
8316 | ||
3d3ab540 RP |
8317 | The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which |
8318 | serves as a repeater. The mailing list and the newsgroup carry exactly | |
8319 | the same messages. Often people think of posting bug reports to the | |
8320 | newsgroup instead of mailing them. This appears to work, but it has one | |
8321 | problem which can be crucial: a newsgroup posting often lacks a mail | |
8322 | path back to the sender. Thus, if we need to ask for more information, | |
8323 | we may be unable to reach you. For this reason, it is better to send | |
8324 | bug reports to the mailing list. | |
70b88761 RP |
8325 | |
8326 | As a last resort, send bug reports on paper to: | |
8327 | ||
8328 | @example | |
8329 | GNU Debugger Bugs | |
3d3ab540 | 8330 | Free Software Foundation |
70b88761 RP |
8331 | 545 Tech Square |
8332 | Cambridge, MA 02139 | |
8333 | @end example | |
8334 | ||
8335 | The fundamental principle of reporting bugs usefully is this: | |
8336 | @strong{report all the facts}. If you are not sure whether to state a | |
8337 | fact or leave it out, state it! | |
8338 | ||
8339 | Often people omit facts because they think they know what causes the | |
29a2b744 | 8340 | problem and assume that some details do not matter. Thus, you might |
70b88761 | 8341 | assume that the name of the variable you use in an example does not matter. |
29a2b744 | 8342 | Well, probably it does not, but one cannot be sure. Perhaps the bug is a |
70b88761 RP |
8343 | stray memory reference which happens to fetch from the location where that |
8344 | name is stored in memory; perhaps, if the name were different, the contents | |
8345 | of that location would fool the debugger into doing the right thing despite | |
8346 | the bug. Play it safe and give a specific, complete example. That is the | |
8347 | easiest thing for you to do, and the most helpful. | |
8348 | ||
8349 | Keep in mind that the purpose of a bug report is to enable us to fix | |
1041a570 | 8350 | the bug if it is new to us. It is not as important as what happens if |
70b88761 RP |
8351 | the bug is already known. Therefore, always write your bug reports on |
8352 | the assumption that the bug has not been reported previously. | |
8353 | ||
8354 | Sometimes people give a few sketchy facts and ask, ``Does this ring a | |
8355 | bell?'' Those bug reports are useless, and we urge everyone to | |
8356 | @emph{refuse to respond to them} except to chide the sender to report | |
8357 | bugs properly. | |
8358 | ||
8359 | To enable us to fix the bug, you should include all these things: | |
8360 | ||
8361 | @itemize @bullet | |
8362 | @item | |
18fae2a8 | 8363 | The version of @value{GDBN}. @value{GDBN} announces it if you start with no |
70b88761 RP |
8364 | arguments; you can also print it at any time using @code{show version}. |
8365 | ||
1041a570 | 8366 | Without this, we will not know whether there is any point in looking for |
18fae2a8 | 8367 | the bug in the current version of @value{GDBN}. |
70b88761 RP |
8368 | |
8369 | @item | |
ddf21240 JG |
8370 | The type of machine you are using, and the operating system name and |
8371 | version number. | |
70b88761 RP |
8372 | |
8373 | @item | |
18fae2a8 RP |
8374 | What compiler (and its version) was used to compile @value{GDBN}---e.g. |
8375 | ``@value{GCC}--2.0''. | |
70b88761 | 8376 | |
ddf21240 JG |
8377 | @item |
8378 | What compiler (and its version) was used to compile the program you | |
18fae2a8 | 8379 | are debugging---e.g. ``@value{GCC}--2.0''. |
ddf21240 | 8380 | |
70b88761 RP |
8381 | @item |
8382 | The command arguments you gave the compiler to compile your example and | |
8383 | observe the bug. For example, did you use @samp{-O}? To guarantee | |
1041a570 | 8384 | you will not omit something important, list them all. A copy of the |
ddf21240 | 8385 | Makefile (or the output from make) is sufficient. |
70b88761 RP |
8386 | |
8387 | If we were to try to guess the arguments, we would probably guess wrong | |
8388 | and then we might not encounter the bug. | |
8389 | ||
8390 | @item | |
ddf21240 JG |
8391 | A complete input script, and all necessary source files, that will |
8392 | reproduce the bug. | |
70b88761 RP |
8393 | |
8394 | @item | |
8395 | A description of what behavior you observe that you believe is | |
8396 | incorrect. For example, ``It gets a fatal signal.'' | |
8397 | ||
18fae2a8 | 8398 | Of course, if the bug is that @value{GDBN} gets a fatal signal, then we will |
70b88761 RP |
8399 | certainly notice it. But if the bug is incorrect output, we might not |
8400 | notice unless it is glaringly wrong. We are human, after all. You | |
8401 | might as well not give us a chance to make a mistake. | |
8402 | ||
8403 | Even if the problem you experience is a fatal signal, you should still | |
8404 | say so explicitly. Suppose something strange is going on, such as, | |
18fae2a8 | 8405 | your copy of @value{GDBN} is out of synch, or you have encountered a |
70b88761 RP |
8406 | bug in the C library on your system. (This has happened!) Your copy |
8407 | might crash and ours would not. If you told us to expect a crash, | |
8408 | then when ours fails to crash, we would know that the bug was not | |
8409 | happening for us. If you had not told us to expect a crash, then we | |
8410 | would not be able to draw any conclusion from our observations. | |
8411 | ||
8412 | @item | |
18fae2a8 RP |
8413 | If you wish to suggest changes to the @value{GDBN} source, send us context |
8414 | diffs. If you even discuss something in the @value{GDBN} source, refer to | |
70b88761 RP |
8415 | it by context, not by line number. |
8416 | ||
1041a570 | 8417 | The line numbers in our development sources will not match those in your |
70b88761 | 8418 | sources. Your line numbers would convey no useful information to us. |
70b88761 RP |
8419 | @end itemize |
8420 | ||
8421 | Here are some things that are not necessary: | |
8422 | ||
8423 | @itemize @bullet | |
8424 | @item | |
8425 | A description of the envelope of the bug. | |
8426 | ||
8427 | Often people who encounter a bug spend a lot of time investigating | |
8428 | which changes to the input file will make the bug go away and which | |
8429 | changes will not affect it. | |
8430 | ||
8431 | This is often time consuming and not very useful, because the way we | |
8432 | will find the bug is by running a single example under the debugger | |
8433 | with breakpoints, not by pure deduction from a series of examples. | |
8434 | We recommend that you save your time for something else. | |
8435 | ||
8436 | Of course, if you can find a simpler example to report @emph{instead} | |
8437 | of the original one, that is a convenience for us. Errors in the | |
8438 | output will be easier to spot, running under the debugger will take | |
e251e767 | 8439 | less time, etc. |
70b88761 | 8440 | |
29a2b744 | 8441 | However, simplification is not vital; if you do not want to do this, |
70b88761 RP |
8442 | report the bug anyway and send us the entire test case you used. |
8443 | ||
8444 | @item | |
8445 | A patch for the bug. | |
8446 | ||
29a2b744 | 8447 | A patch for the bug does help us if it is a good one. But do not omit |
70b88761 RP |
8448 | the necessary information, such as the test case, on the assumption that |
8449 | a patch is all we need. We might see problems with your patch and decide | |
8450 | to fix the problem another way, or we might not understand it at all. | |
8451 | ||
18fae2a8 | 8452 | Sometimes with a program as complicated as @value{GDBN} it is very hard to |
70b88761 | 8453 | construct an example that will make the program follow a certain path |
1041a570 RP |
8454 | through the code. If you do not send us the example, we will not be able |
8455 | to construct one, so we will not be able to verify that the bug is fixed. | |
70b88761 | 8456 | |
29a2b744 | 8457 | And if we cannot understand what bug you are trying to fix, or why your |
1041a570 | 8458 | patch should be an improvement, we will not install it. A test case will |
70b88761 RP |
8459 | help us to understand. |
8460 | ||
8461 | @item | |
8462 | A guess about what the bug is or what it depends on. | |
8463 | ||
29a2b744 | 8464 | Such guesses are usually wrong. Even we cannot guess right about such |
70b88761 RP |
8465 | things without first using the debugger to find the facts. |
8466 | @end itemize | |
8467 | ||
ed447b95 | 8468 | @ifset have-readline-appendices |
cacf5942 RP |
8469 | @include rluser.texinfo |
8470 | @include inc-hist.texi | |
ed447b95 | 8471 | @end ifset |
70b88761 | 8472 | |
18fae2a8 | 8473 | @ifset NOVEL |
4eb4cf57 | 8474 | @node Renamed Commands |
70b88761 RP |
8475 | @appendix Renamed Commands |
8476 | ||
c7cb8acb | 8477 | The following commands were renamed in GDB 4, in order to make the |
70b88761 RP |
8478 | command set as a whole more consistent and easier to use and remember: |
8479 | ||
e251e767 RP |
8480 | @kindex add-syms |
8481 | @kindex delete environment | |
8482 | @kindex info copying | |
8483 | @kindex info convenience | |
8484 | @kindex info directories | |
8485 | @kindex info editing | |
8486 | @kindex info history | |
8487 | @kindex info targets | |
8488 | @kindex info values | |
8489 | @kindex info version | |
8490 | @kindex info warranty | |
8491 | @kindex set addressprint | |
8492 | @kindex set arrayprint | |
8493 | @kindex set prettyprint | |
8494 | @kindex set screen-height | |
8495 | @kindex set screen-width | |
8496 | @kindex set unionprint | |
8497 | @kindex set vtblprint | |
8498 | @kindex set demangle | |
8499 | @kindex set asm-demangle | |
8500 | @kindex set sevenbit-strings | |
8501 | @kindex set array-max | |
8502 | @kindex set caution | |
8503 | @kindex set history write | |
8504 | @kindex show addressprint | |
8505 | @kindex show arrayprint | |
8506 | @kindex show prettyprint | |
8507 | @kindex show screen-height | |
8508 | @kindex show screen-width | |
8509 | @kindex show unionprint | |
8510 | @kindex show vtblprint | |
8511 | @kindex show demangle | |
8512 | @kindex show asm-demangle | |
8513 | @kindex show sevenbit-strings | |
8514 | @kindex show array-max | |
8515 | @kindex show caution | |
8516 | @kindex show history write | |
8517 | @kindex unset | |
70b88761 | 8518 | |
92b73793 | 8519 | @c TEXI2ROFF-KILL |
70b88761 | 8520 | @ifinfo |
92b73793 | 8521 | @c END TEXI2ROFF-KILL |
cf496415 RP |
8522 | @example |
8523 | OLD COMMAND NEW COMMAND | |
92b73793 | 8524 | @c TEXI2ROFF-KILL |
cf496415 | 8525 | --------------- ------------------------------- |
92b73793 | 8526 | @c END TEXI2ROFF-KILL |
cf496415 RP |
8527 | add-syms add-symbol-file |
8528 | delete environment unset environment | |
8529 | info convenience show convenience | |
8530 | info copying show copying | |
e251e767 | 8531 | info directories show directories |
cf496415 RP |
8532 | info editing show commands |
8533 | info history show values | |
8534 | info targets help target | |
8535 | info values show values | |
8536 | info version show version | |
8537 | info warranty show warranty | |
8538 | set/show addressprint set/show print address | |
8539 | set/show array-max set/show print elements | |
8540 | set/show arrayprint set/show print array | |
8541 | set/show asm-demangle set/show print asm-demangle | |
8542 | set/show caution set/show confirm | |
8543 | set/show demangle set/show print demangle | |
8544 | set/show history write set/show history save | |
8545 | set/show prettyprint set/show print pretty | |
8546 | set/show screen-height set/show height | |
8547 | set/show screen-width set/show width | |
8548 | set/show sevenbit-strings set/show print sevenbit-strings | |
8549 | set/show unionprint set/show print union | |
8550 | set/show vtblprint set/show print vtbl | |
8551 | ||
8552 | unset [No longer an alias for delete] | |
8553 | @end example | |
92b73793 | 8554 | @c TEXI2ROFF-KILL |
70b88761 RP |
8555 | @end ifinfo |
8556 | ||
8557 | @tex | |
8558 | \vskip \parskip\vskip \baselineskip | |
8559 | \halign{\tt #\hfil &\qquad#&\tt #\hfil\cr | |
8560 | {\bf Old Command} &&{\bf New Command}\cr | |
8561 | add-syms &&add-symbol-file\cr | |
8562 | delete environment &&unset environment\cr | |
8563 | info convenience &&show convenience\cr | |
8564 | info copying &&show copying\cr | |
8565 | info directories &&show directories \cr | |
8566 | info editing &&show commands\cr | |
8567 | info history &&show values\cr | |
8568 | info targets &&help target\cr | |
8569 | info values &&show values\cr | |
8570 | info version &&show version\cr | |
8571 | info warranty &&show warranty\cr | |
8572 | set{\rm / }show addressprint &&set{\rm / }show print address\cr | |
8573 | set{\rm / }show array-max &&set{\rm / }show print elements\cr | |
8574 | set{\rm / }show arrayprint &&set{\rm / }show print array\cr | |
8575 | set{\rm / }show asm-demangle &&set{\rm / }show print asm-demangle\cr | |
8576 | set{\rm / }show caution &&set{\rm / }show confirm\cr | |
8577 | set{\rm / }show demangle &&set{\rm / }show print demangle\cr | |
8578 | set{\rm / }show history write &&set{\rm / }show history save\cr | |
8579 | set{\rm / }show prettyprint &&set{\rm / }show print pretty\cr | |
8580 | set{\rm / }show screen-height &&set{\rm / }show height\cr | |
8581 | set{\rm / }show screen-width &&set{\rm / }show width\cr | |
8582 | set{\rm / }show sevenbit-strings &&set{\rm / }show print sevenbit-strings\cr | |
8583 | set{\rm / }show unionprint &&set{\rm / }show print union\cr | |
8584 | set{\rm / }show vtblprint &&set{\rm / }show print vtbl\cr | |
8585 | \cr | |
8586 | unset &&\rm(No longer an alias for delete)\cr | |
8587 | } | |
8588 | @end tex | |
92b73793 | 8589 | @c END TEXI2ROFF-KILL |
18fae2a8 | 8590 | @end ifset |
70b88761 | 8591 | |
18fae2a8 | 8592 | @ifclear PRECONFIGURED |
4eb4cf57 | 8593 | @node Formatting Documentation |
77b46d13 JG |
8594 | @appendix Formatting the Documentation |
8595 | ||
8596 | @cindex GDB reference card | |
8597 | @cindex reference card | |
8598 | The GDB 4 release includes an already-formatted reference card, ready | |
b1385986 | 8599 | for printing with PostScript or GhostScript, in the @file{gdb} |
ed447b95 RP |
8600 | subdirectory of the main source directory@footnote{In |
8601 | @file{gdb-@value{GDBVN}/gdb/refcard.ps} of the version @value{GDBVN} | |
8602 | release.}. If you can use PostScript or GhostScript with your printer, | |
8603 | you can print the reference card immediately with @file{refcard.ps}. | |
77b46d13 JG |
8604 | |
8605 | The release also includes the source for the reference card. You | |
8606 | can format it, using @TeX{}, by typing: | |
8607 | ||
8608 | @example | |
8609 | make refcard.dvi | |
8610 | @end example | |
8611 | ||
8612 | The GDB reference card is designed to print in landscape mode on US | |
8613 | ``letter'' size paper; that is, on a sheet 11 inches wide by 8.5 inches | |
8614 | high. You will need to specify this form of printing as an option to | |
8615 | your @sc{dvi} output program. | |
8616 | ||
8617 | @cindex documentation | |
8618 | ||
8619 | All the documentation for GDB comes as part of the machine-readable | |
8620 | distribution. The documentation is written in Texinfo format, which is | |
8621 | a documentation system that uses a single source file to produce both | |
8622 | on-line information and a printed manual. You can use one of the Info | |
8623 | formatting commands to create the on-line version of the documentation | |
8624 | and @TeX{} (or @code{texi2roff}) to typeset the printed version. | |
8625 | ||
8626 | GDB includes an already formatted copy of the on-line Info version of | |
8627 | this manual in the @file{gdb} subdirectory. The main Info file is | |
8628 | @file{gdb-@var{version-number}/gdb/gdb.info}, and it refers to | |
a89f94c2 RP |
8629 | subordinate files matching @samp{gdb.info*} in the same directory. If |
8630 | necessary, you can print out these files, or read them with any editor; | |
8631 | but they are easier to read using the @code{info} subsystem in GNU Emacs | |
8632 | or the standalone @code{info} program, available as part of the GNU | |
8633 | Texinfo distribution. | |
77b46d13 JG |
8634 | |
8635 | If you want to format these Info files yourself, you need one of the | |
8636 | Info formatting programs, such as @code{texinfo-format-buffer} or | |
8637 | @code{makeinfo}. | |
8638 | ||
8639 | If you have @code{makeinfo} installed, and are in the top level GDB | |
18fae2a8 | 8640 | source directory (@file{gdb-@value{GDBVN}}, in the case of version @value{GDBVN}), you can |
77b46d13 JG |
8641 | make the Info file by typing: |
8642 | ||
8643 | @example | |
8644 | cd gdb | |
8645 | make gdb.info | |
8646 | @end example | |
8647 | ||
8648 | If you want to typeset and print copies of this manual, you need | |
8649 | @TeX{}, a printing program such as @code{lpr}, and @file{texinfo.tex}, | |
8650 | the Texinfo definitions file. | |
8651 | ||
83bfcbae | 8652 | @TeX{} is a typesetting program; it does not print files directly, but |
77b46d13 JG |
8653 | produces output files called @sc{dvi} files. To print a typeset |
8654 | document, you need a program to print @sc{dvi} files. If your system | |
8655 | has @TeX{} installed, chances are it has such a program. The precise | |
8656 | command to use depends on your system; @kbd{lpr -d} is common; another | |
8657 | is @kbd{dvips}. The @sc{dvi} print command may require a file name | |
8658 | without any extension or a @samp{.dvi} extension. | |
8659 | ||
8660 | @TeX{} also requires a macro definitions file called | |
8661 | @file{texinfo.tex}. This file tells @TeX{} how to typeset a document | |
8662 | written in Texinfo format. On its own, @TeX{} cannot read, much less | |
8663 | typeset a Texinfo file. @file{texinfo.tex} is distributed with GDB | |
8664 | and is located in the @file{gdb-@var{version-number}/texinfo} | |
8665 | directory. | |
8666 | ||
8667 | If you have @TeX{} and a @sc{dvi} printer program installed, you can | |
8668 | typeset and print this manual. First switch to the the @file{gdb} | |
8669 | subdirectory of the main source directory (for example, to | |
18fae2a8 | 8670 | @file{gdb-@value{GDBVN}/gdb}) and then type: |
77b46d13 JG |
8671 | |
8672 | @example | |
8673 | make gdb.dvi | |
8674 | @end example | |
8675 | ||
4eb4cf57 | 8676 | @node Installing GDB |
c7cb8acb RP |
8677 | @appendix Installing GDB |
8678 | @cindex configuring GDB | |
70b88761 RP |
8679 | @cindex installation |
8680 | ||
ed447b95 RP |
8681 | GDB comes with a @code{configure} script that automates the process |
8682 | of preparing GDB for installation; you can then use @code{make} to | |
8683 | build the @code{gdb} program. | |
f672bb7f RP |
8684 | @iftex |
8685 | @c irrelevant in info file; it's as current as the code it lives with. | |
ed447b95 RP |
8686 | @footnote{If you have a more recent version of GDB than @value{GDBVN}, |
8687 | look at the @file{README} file in the sources; we may have improved the | |
8688 | installation procedures since publishing this manual.} | |
f672bb7f RP |
8689 | @end iftex |
8690 | ||
c7cb8acb | 8691 | The GDB distribution includes all the source code you need for GDB in |
1041a570 RP |
8692 | a single directory, whose name is usually composed by appending the |
8693 | version number to @samp{gdb}. | |
8694 | ||
ed447b95 RP |
8695 | For example, the GDB version @value{GDBVN} distribution is in the |
8696 | @file{gdb-@value{GDBVN}} directory. That directory contains: | |
b80282d5 | 8697 | |
3d3ab540 | 8698 | @table @code |
18fae2a8 | 8699 | @item gdb-@value{GDBVN}/configure @r{(and supporting files)} |
c7cb8acb | 8700 | script for configuring GDB and all its supporting libraries. |
b80282d5 | 8701 | |
18fae2a8 | 8702 | @item gdb-@value{GDBVN}/gdb |
c7cb8acb | 8703 | the source specific to GDB itself |
3d3ab540 | 8704 | |
18fae2a8 | 8705 | @item gdb-@value{GDBVN}/bfd |
77b46d13 | 8706 | source for the Binary File Descriptor library |
3d3ab540 | 8707 | |
18fae2a8 | 8708 | @item gdb-@value{GDBVN}/include |
b80282d5 | 8709 | GNU include files |
3d3ab540 | 8710 | |
18fae2a8 | 8711 | @item gdb-@value{GDBVN}/libiberty |
3d3ab540 RP |
8712 | source for the @samp{-liberty} free software library |
8713 | ||
18fae2a8 | 8714 | @item gdb-@value{GDBVN}/opcodes |
3214c51c JG |
8715 | source for the library of opcode tables and disassemblers |
8716 | ||
18fae2a8 | 8717 | @item gdb-@value{GDBVN}/readline |
b80282d5 | 8718 | source for the GNU command-line interface |
77b46d13 | 8719 | |
18fae2a8 | 8720 | @item gdb-@value{GDBVN}/glob |
77b46d13 JG |
8721 | source for the GNU filename pattern-matching subroutine |
8722 | ||
18fae2a8 | 8723 | @item gdb-@value{GDBVN}/mmalloc |
77b46d13 | 8724 | source for the GNU memory-mapped malloc package |
3d3ab540 | 8725 | @end table |
1041a570 | 8726 | |
c7cb8acb | 8727 | The simplest way to configure and build GDB is to run @code{configure} |
1041a570 | 8728 | from the @file{gdb-@var{version-number}} source directory, which in |
18fae2a8 | 8729 | this example is the @file{gdb-@value{GDBVN}} directory. |
1041a570 RP |
8730 | |
8731 | First switch to the @file{gdb-@var{version-number}} source directory | |
8732 | if you are not already in it; then run @code{configure}. Pass the | |
c7cb8acb | 8733 | identifier for the platform on which GDB will run as an |
1041a570 RP |
8734 | argument. |
8735 | ||
8736 | For example: | |
8737 | ||
7463aadd | 8738 | @example |
18fae2a8 | 8739 | cd gdb-@value{GDBVN} |
3d3ab540 | 8740 | ./configure @var{host} |
7463aadd RP |
8741 | make |
8742 | @end example | |
1041a570 | 8743 | |
7463aadd | 8744 | @noindent |
1041a570 | 8745 | where @var{host} is an identifier such as @samp{sun4} or |
c7cb8acb | 8746 | @samp{decstation}, that identifies the platform where GDB will run. |
1041a570 | 8747 | |
38962738 RP |
8748 | Running @samp{configure @var{host}} followed by @code{make} builds the |
8749 | @file{bfd}, @file{readline}, @file{mmalloc}, and @file{libiberty} | |
8750 | libraries, then @code{gdb} itself. The configured source files, and the | |
8751 | binaries, are left in the corresponding source directories. | |
3d3ab540 | 8752 | |
e251e767 | 8753 | @code{configure} is a Bourne-shell (@code{/bin/sh}) script; if your |
29a2b744 | 8754 | system does not recognize this automatically when you run a different |
1041a570 RP |
8755 | shell, you may need to run @code{sh} on it explicitly: |
8756 | ||
8757 | @example | |
8758 | sh configure @var{host} | |
8759 | @end example | |
e251e767 | 8760 | |
f672bb7f RP |
8761 | If you run @code{configure} from a directory that contains source |
8762 | directories for multiple libraries or programs, such as the | |
18fae2a8 | 8763 | @file{gdb-@value{GDBVN}} source directory for version @value{GDBVN}, @code{configure} |
f672bb7f | 8764 | creates configuration files for every directory level underneath (unless |
98349959 | 8765 | you tell it not to, with the @samp{--norecursion} option). |
f672bb7f RP |
8766 | |
8767 | You can run the @code{configure} script from any of the | |
c7cb8acb | 8768 | subordinate directories in the GDB distribution, if you only want to |
1041a570 RP |
8769 | configure that subdirectory; but be sure to specify a path to it. |
8770 | ||
18fae2a8 | 8771 | For example, with version @value{GDBVN}, type the following to configure only |
1041a570 RP |
8772 | the @code{bfd} subdirectory: |
8773 | ||
e251e767 | 8774 | @example |
203eea5d | 8775 | @group |
18fae2a8 | 8776 | cd gdb-@value{GDBVN}/bfd |
e251e767 | 8777 | ../configure @var{host} |
203eea5d | 8778 | @end group |
e251e767 RP |
8779 | @end example |
8780 | ||
18fae2a8 | 8781 | You can install @code{@value{GDBP}} anywhere; it has no hardwired paths. |
1041a570 RP |
8782 | However, you should make sure that the shell on your path (named by |
8783 | the @samp{SHELL} environment variable) is publicly readable. Remember | |
c7cb8acb RP |
8784 | that GDB uses the shell to start your program---some systems refuse to |
8785 | let GDB debug child processes whose programs are not readable. | |
3d3ab540 RP |
8786 | |
8787 | @menu | |
c7cb8acb | 8788 | * Separate Objdir:: Compiling GDB in another directory |
b80282d5 RP |
8789 | * Config Names:: Specifying names for hosts and targets |
8790 | * configure Options:: Summary of options for configure | |
3d3ab540 RP |
8791 | @end menu |
8792 | ||
4eb4cf57 | 8793 | @node Separate Objdir |
c7cb8acb | 8794 | @section Compiling GDB in Another Directory |
1041a570 | 8795 | |
c7cb8acb | 8796 | If you want to run GDB versions for several host or target machines, |
ed447b95 | 8797 | you need a different @code{gdb} compiled for each combination of |
1041a570 | 8798 | host and target. @code{configure} is designed to make this easy by |
f672bb7f RP |
8799 | allowing you to generate each configuration in a separate subdirectory, |
8800 | rather than in the source directory. If your @code{make} program | |
8801 | handles the @samp{VPATH} feature (GNU @code{make} does), running | |
ed447b95 | 8802 | @code{make} in each of these directories builds the @code{gdb} |
f672bb7f | 8803 | program specified there. |
b80282d5 | 8804 | |
c7cb8acb | 8805 | To build @code{gdb} in a separate directory, run @code{configure} |
f672bb7f | 8806 | with the @samp{--srcdir} option to specify where to find the source. |
77b46d13 JG |
8807 | (You'll also need to specify a path to find @code{configure} |
8808 | itself from your working directory. If the path to @code{configure} | |
8809 | would be the same as the argument to @samp{--srcdir}, you can leave out | |
8810 | the @samp{--srcdir} option; it will be assumed.) | |
1041a570 | 8811 | |
18fae2a8 | 8812 | For example, with version @value{GDBVN}, you can build GDB in a separate |
f672bb7f | 8813 | directory for a Sun 4 like this: |
70b88761 RP |
8814 | |
8815 | @example | |
3d3ab540 | 8816 | @group |
18fae2a8 | 8817 | cd gdb-@value{GDBVN} |
f672bb7f RP |
8818 | mkdir ../gdb-sun4 |
8819 | cd ../gdb-sun4 | |
18fae2a8 | 8820 | ../gdb-@value{GDBVN}/configure sun4 |
70b88761 | 8821 | make |
3d3ab540 | 8822 | @end group |
70b88761 RP |
8823 | @end example |
8824 | ||
f672bb7f RP |
8825 | When @code{configure} builds a configuration using a remote source |
8826 | directory, it creates a tree for the binaries with the same structure | |
8827 | (and using the same names) as the tree under the source directory. In | |
8828 | the example, you'd find the Sun 4 library @file{libiberty.a} in the | |
c7cb8acb | 8829 | directory @file{gdb-sun4/libiberty}, and GDB itself in |
f672bb7f | 8830 | @file{gdb-sun4/gdb}. |
1041a570 | 8831 | |
38962738 | 8832 | One popular reason to build several GDB configurations in separate |
c7cb8acb | 8833 | directories is to configure GDB for cross-compiling (where GDB |
f672bb7f RP |
8834 | runs on one machine---the host---while debugging programs that run on |
8835 | another machine---the target). You specify a cross-debugging target by | |
8836 | giving the @samp{--target=@var{target}} option to @code{configure}. | |
c7637ea6 | 8837 | |
1041a570 | 8838 | When you run @code{make} to build a program or library, you must run |
f672bb7f RP |
8839 | it in a configured directory---whatever directory you were in when you |
8840 | called @code{configure} (or one of its subdirectories). | |
c7637ea6 RP |
8841 | |
8842 | The @code{Makefile} generated by @code{configure} for each source | |
f672bb7f | 8843 | directory also runs recursively. If you type @code{make} in a source |
18fae2a8 RP |
8844 | directory such as @file{gdb-@value{GDBVN}} (or in a separate configured |
8845 | directory configured with @samp{--srcdir=@var{path}/gdb-@value{GDBVN}}), you | |
ed447b95 | 8846 | will build all the required libraries, and then build GDB. |
3d3ab540 | 8847 | |
f672bb7f RP |
8848 | When you have multiple hosts or targets configured in separate |
8849 | directories, you can run @code{make} on them in parallel (for example, | |
8850 | if they are NFS-mounted on each of the hosts); they will not interfere | |
8851 | with each other. | |
3d3ab540 | 8852 | |
4eb4cf57 | 8853 | @node Config Names |
b80282d5 RP |
8854 | @section Specifying Names for Hosts and Targets |
8855 | ||
8856 | The specifications used for hosts and targets in the @code{configure} | |
8857 | script are based on a three-part naming scheme, but some short predefined | |
8858 | aliases are also supported. The full naming scheme encodes three pieces | |
e251e767 | 8859 | of information in the following pattern: |
1041a570 | 8860 | |
b80282d5 RP |
8861 | @example |
8862 | @var{architecture}-@var{vendor}-@var{os} | |
8863 | @end example | |
8864 | ||
8865 | For example, you can use the alias @code{sun4} as a @var{host} argument | |
5e3186ab | 8866 | or in a @code{--target=@var{target}} option, but the equivalent full name |
e251e767 | 8867 | is @samp{sparc-sun-sunos4}. |
b80282d5 | 8868 | |
c7cb8acb | 8869 | The @code{configure} script accompanying GDB does not provide |
b80282d5 RP |
8870 | any query facility to list all supported host and target names or |
8871 | aliases. @code{configure} calls the Bourne shell script | |
8872 | @code{config.sub} to map abbreviations to full names; you can read the | |
8873 | script, if you wish, or you can use it to test your guesses on | |
8874 | abbreviations---for example: | |
1041a570 | 8875 | |
b1385986 | 8876 | @smallexample |
b80282d5 | 8877 | % sh config.sub sun4 |
6a8cb0e7 | 8878 | sparc-sun-sunos411 |
b80282d5 | 8879 | % sh config.sub sun3 |
6a8cb0e7 | 8880 | m68k-sun-sunos411 |
b80282d5 | 8881 | % sh config.sub decstation |
6a8cb0e7 | 8882 | mips-dec-ultrix42 |
b80282d5 RP |
8883 | % sh config.sub hp300bsd |
8884 | m68k-hp-bsd | |
8885 | % sh config.sub i386v | |
6a8cb0e7 | 8886 | i386-unknown-sysv |
e94b4a2b | 8887 | % sh config.sub i786v |
6a8cb0e7 | 8888 | Invalid configuration `i786v': machine `i786v' not recognized |
b1385986 | 8889 | @end smallexample |
1041a570 | 8890 | |
c7637ea6 | 8891 | @noindent |
1041a570 | 8892 | @code{config.sub} is also distributed in the GDB source |
18fae2a8 | 8893 | directory (@file{gdb-@value{GDBVN}}, for version @value{GDBVN}). |
b80282d5 | 8894 | |
4eb4cf57 | 8895 | @node configure Options |
3d3ab540 | 8896 | @section @code{configure} Options |
7463aadd | 8897 | |
d48da190 | 8898 | Here is a summary of the @code{configure} options and arguments that |
18fae2a8 | 8899 | are most often useful for building @value{GDBN}. @code{configure} also has |
d48da190 RP |
8900 | several other options not listed here. @inforef{What Configure |
8901 | Does,,configure.info}, for a full explanation of @code{configure}. | |
8902 | @c FIXME: Would this be more, or less, useful as an xref (ref to printed | |
8903 | @c manual in the printed manual, ref to info file only from the info file)? | |
7463aadd RP |
8904 | |
8905 | @example | |
d48da190 RP |
8906 | configure @r{[}--help@r{]} |
8907 | @r{[}--prefix=@var{dir}@r{]} | |
8908 | @r{[}--srcdir=@var{path}@r{]} | |
f672bb7f RP |
8909 | @r{[}--norecursion@r{]} @r{[}--rm@r{]} |
8910 | @r{[}--target=@var{target}@r{]} @var{host} | |
7463aadd | 8911 | @end example |
1041a570 | 8912 | |
3d3ab540 | 8913 | @noindent |
f672bb7f RP |
8914 | You may introduce options with a single @samp{-} rather than |
8915 | @samp{--} if you prefer; but you may abbreviate option names if you use | |
8916 | @samp{--}. | |
70b88761 RP |
8917 | |
8918 | @table @code | |
d48da190 RP |
8919 | @item --help |
8920 | Display a quick summary of how to invoke @code{configure}. | |
8921 | ||
8922 | @item -prefix=@var{dir} | |
8923 | Configure the source to install programs and files under directory | |
8924 | @file{@var{dir}}. | |
8925 | ||
f672bb7f | 8926 | @item --srcdir=@var{path} |
6ca72cc6 RP |
8927 | @strong{Warning: using this option requires GNU @code{make}, or another |
8928 | @code{make} that implements the @code{VPATH} feature.}@* | |
f672bb7f | 8929 | Use this option to make configurations in directories separate from the |
c7cb8acb | 8930 | GDB source directories. Among other things, you can use this to |
f672bb7f RP |
8931 | build (or maintain) several configurations simultaneously, in separate |
8932 | directories. @code{configure} writes configuration specific files in | |
8933 | the current directory, but arranges for them to use the source in the | |
8934 | directory @var{path}. @code{configure} will create directories under | |
8935 | the working directory in parallel to the source directories below | |
8936 | @var{path}. | |
8937 | ||
8938 | @item --norecursion | |
8939 | Configure only the directory level where @code{configure} is executed; do not | |
7463aadd RP |
8940 | propagate configuration to subdirectories. |
8941 | ||
f672bb7f | 8942 | @item --rm |
b80282d5 | 8943 | Remove the configuration that the other arguments specify. |
7463aadd | 8944 | |
29a2b744 | 8945 | @c This does not work (yet if ever). FIXME. |
f672bb7f | 8946 | @c @item --parse=@var{lang} @dots{} |
c7cb8acb RP |
8947 | @c Configure the GDB expression parser to parse the listed languages. |
8948 | @c @samp{all} configures GDB for all supported languages. To get a | |
d7b569d5 | 8949 | @c list of all supported languages, omit the argument. Without this |
c7cb8acb | 8950 | @c option, GDB is configured to parse all supported languages. |
c2bbbb22 | 8951 | |
f672bb7f | 8952 | @item --target=@var{target} |
c7cb8acb RP |
8953 | Configure GDB for cross-debugging programs running on the specified |
8954 | @var{target}. Without this option, GDB is configured to debug | |
8955 | programs that run on the same machine (@var{host}) as GDB itself. | |
b80282d5 RP |
8956 | |
8957 | There is no convenient way to generate a list of all available targets. | |
7463aadd RP |
8958 | |
8959 | @item @var{host} @dots{} | |
c7cb8acb | 8960 | Configure GDB to run on the specified @var{host}. |
b80282d5 RP |
8961 | |
8962 | There is no convenient way to generate a list of all available hosts. | |
70b88761 RP |
8963 | @end table |
8964 | ||
3d3ab540 RP |
8965 | @noindent |
8966 | @code{configure} accepts other options, for compatibility with | |
b80282d5 | 8967 | configuring other GNU tools recursively; but these are the only |
c7cb8acb | 8968 | options that affect GDB or its supporting libraries. |
18fae2a8 | 8969 | @end ifclear |
3d3ab540 | 8970 | |
18fae2a8 | 8971 | @ifclear AGGLOMERATION |
4eb4cf57 | 8972 | @node Copying |
70b88761 | 8973 | @unnumbered GNU GENERAL PUBLIC LICENSE |
7463aadd | 8974 | @center Version 2, June 1991 |
70b88761 RP |
8975 | |
8976 | @display | |
7463aadd | 8977 | Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. |
70b88761 RP |
8978 | 675 Mass Ave, Cambridge, MA 02139, USA |
8979 | ||
8980 | Everyone is permitted to copy and distribute verbatim copies | |
8981 | of this license document, but changing it is not allowed. | |
8982 | @end display | |
8983 | ||
8984 | @unnumberedsec Preamble | |
8985 | ||
7463aadd RP |
8986 | The licenses for most software are designed to take away your |
8987 | freedom to share and change it. By contrast, the GNU General Public | |
70b88761 | 8988 | License is intended to guarantee your freedom to share and change free |
7463aadd RP |
8989 | software---to make sure the software is free for all its users. This |
8990 | General Public License applies to most of the Free Software | |
8991 | Foundation's software and to any other program whose authors commit to | |
8992 | using it. (Some other Free Software Foundation software is covered by | |
8993 | the GNU Library General Public License instead.) You can apply it to | |
8994 | your programs, too. | |
70b88761 RP |
8995 | |
8996 | When we speak of free software, we are referring to freedom, not | |
7463aadd RP |
8997 | price. Our General Public Licenses are designed to make sure that you |
8998 | have the freedom to distribute copies of free software (and charge for | |
8999 | this service if you wish), that you receive source code or can get it | |
9000 | if you want it, that you can change the software or use pieces of it | |
9001 | in new free programs; and that you know you can do these things. | |
70b88761 RP |
9002 | |
9003 | To protect your rights, we need to make restrictions that forbid | |
9004 | anyone to deny you these rights or to ask you to surrender the rights. | |
9005 | These restrictions translate to certain responsibilities for you if you | |
9006 | distribute copies of the software, or if you modify it. | |
9007 | ||
7463aadd | 9008 | For example, if you distribute copies of such a program, whether |
70b88761 RP |
9009 | gratis or for a fee, you must give the recipients all the rights that |
9010 | you have. You must make sure that they, too, receive or can get the | |
7463aadd RP |
9011 | source code. And you must show them these terms so they know their |
9012 | rights. | |
70b88761 RP |
9013 | |
9014 | We protect your rights with two steps: (1) copyright the software, and | |
9015 | (2) offer you this license which gives you legal permission to copy, | |
9016 | distribute and/or modify the software. | |
9017 | ||
9018 | Also, for each author's protection and ours, we want to make certain | |
9019 | that everyone understands that there is no warranty for this free | |
9020 | software. If the software is modified by someone else and passed on, we | |
9021 | want its recipients to know that what they have is not the original, so | |
9022 | that any problems introduced by others will not reflect on the original | |
9023 | authors' reputations. | |
9024 | ||
7463aadd RP |
9025 | Finally, any free program is threatened constantly by software |
9026 | patents. We wish to avoid the danger that redistributors of a free | |
9027 | program will individually obtain patent licenses, in effect making the | |
9028 | program proprietary. To prevent this, we have made it clear that any | |
9029 | patent must be licensed for everyone's free use or not licensed at all. | |
9030 | ||
70b88761 RP |
9031 | The precise terms and conditions for copying, distribution and |
9032 | modification follow. | |
9033 | ||
9034 | @iftex | |
7463aadd | 9035 | @unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION |
70b88761 RP |
9036 | @end iftex |
9037 | @ifinfo | |
7463aadd | 9038 | @center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION |
70b88761 RP |
9039 | @end ifinfo |
9040 | ||
9041 | @enumerate | |
9042 | @item | |
7463aadd RP |
9043 | This License applies to any program or other work which contains |
9044 | a notice placed by the copyright holder saying it may be distributed | |
9045 | under the terms of this General Public License. The ``Program'', below, | |
9046 | refers to any such program or work, and a ``work based on the Program'' | |
9047 | means either the Program or any derivative work under copyright law: | |
9048 | that is to say, a work containing the Program or a portion of it, | |
9049 | either verbatim or with modifications and/or translated into another | |
9050 | language. (Hereinafter, translation is included without limitation in | |
9051 | the term ``modification''.) Each licensee is addressed as ``you''. | |
9052 | ||
9053 | Activities other than copying, distribution and modification are not | |
9054 | covered by this License; they are outside its scope. The act of | |
9055 | running the Program is not restricted, and the output from the Program | |
9056 | is covered only if its contents constitute a work based on the | |
9057 | Program (independent of having been made by running the Program). | |
9058 | Whether that is true depends on what the Program does. | |
70b88761 RP |
9059 | |
9060 | @item | |
7463aadd RP |
9061 | You may copy and distribute verbatim copies of the Program's |
9062 | source code as you receive it, in any medium, provided that you | |
9063 | conspicuously and appropriately publish on each copy an appropriate | |
9064 | copyright notice and disclaimer of warranty; keep intact all the | |
9065 | notices that refer to this License and to the absence of any warranty; | |
9066 | and give any other recipients of the Program a copy of this License | |
9067 | along with the Program. | |
70b88761 | 9068 | |
7463aadd RP |
9069 | You may charge a fee for the physical act of transferring a copy, and |
9070 | you may at your option offer warranty protection in exchange for a fee. | |
70b88761 | 9071 | |
70b88761 | 9072 | @item |
7463aadd RP |
9073 | You may modify your copy or copies of the Program or any portion |
9074 | of it, thus forming a work based on the Program, and copy and | |
9075 | distribute such modifications or work under the terms of Section 1 | |
9076 | above, provided that you also meet all of these conditions: | |
70b88761 | 9077 | |
1041a570 | 9078 | @enumerate a |
70b88761 | 9079 | @item |
7463aadd RP |
9080 | You must cause the modified files to carry prominent notices |
9081 | stating that you changed the files and the date of any change. | |
70b88761 RP |
9082 | |
9083 | @item | |
7463aadd RP |
9084 | You must cause any work that you distribute or publish, that in |
9085 | whole or in part contains or is derived from the Program or any | |
9086 | part thereof, to be licensed as a whole at no charge to all third | |
9087 | parties under the terms of this License. | |
70b88761 RP |
9088 | |
9089 | @item | |
7463aadd RP |
9090 | If the modified program normally reads commands interactively |
9091 | when run, you must cause it, when started running for such | |
9092 | interactive use in the most ordinary way, to print or display an | |
9093 | announcement including an appropriate copyright notice and a | |
9094 | notice that there is no warranty (or else, saying that you provide | |
9095 | a warranty) and that users may redistribute the program under | |
9096 | these conditions, and telling the user how to view a copy of this | |
9097 | License. (Exception: if the Program itself is interactive but | |
9098 | does not normally print such an announcement, your work based on | |
9099 | the Program is not required to print an announcement.) | |
1041a570 | 9100 | @end enumerate |
7463aadd RP |
9101 | |
9102 | These requirements apply to the modified work as a whole. If | |
9103 | identifiable sections of that work are not derived from the Program, | |
9104 | and can be reasonably considered independent and separate works in | |
9105 | themselves, then this License, and its terms, do not apply to those | |
9106 | sections when you distribute them as separate works. But when you | |
9107 | distribute the same sections as part of a whole which is a work based | |
9108 | on the Program, the distribution of the whole must be on the terms of | |
9109 | this License, whose permissions for other licensees extend to the | |
9110 | entire whole, and thus to each and every part regardless of who wrote it. | |
9111 | ||
9112 | Thus, it is not the intent of this section to claim rights or contest | |
9113 | your rights to work written entirely by you; rather, the intent is to | |
9114 | exercise the right to control the distribution of derivative or | |
9115 | collective works based on the Program. | |
9116 | ||
9117 | In addition, mere aggregation of another work not based on the Program | |
9118 | with the Program (or with a work based on the Program) on a volume of | |
9119 | a storage or distribution medium does not bring the other work under | |
9120 | the scope of this License. | |
70b88761 RP |
9121 | |
9122 | @item | |
7463aadd RP |
9123 | You may copy and distribute the Program (or a work based on it, |
9124 | under Section 2) in object code or executable form under the terms of | |
9125 | Sections 1 and 2 above provided that you also do one of the following: | |
70b88761 | 9126 | |
1041a570 | 9127 | @enumerate a |
70b88761 | 9128 | @item |
7463aadd RP |
9129 | Accompany it with the complete corresponding machine-readable |
9130 | source code, which must be distributed under the terms of Sections | |
9131 | 1 and 2 above on a medium customarily used for software interchange; or, | |
70b88761 RP |
9132 | |
9133 | @item | |
7463aadd RP |
9134 | Accompany it with a written offer, valid for at least three |
9135 | years, to give any third party, for a charge no more than your | |
9136 | cost of physically performing source distribution, a complete | |
9137 | machine-readable copy of the corresponding source code, to be | |
9138 | distributed under the terms of Sections 1 and 2 above on a medium | |
9139 | customarily used for software interchange; or, | |
70b88761 RP |
9140 | |
9141 | @item | |
7463aadd RP |
9142 | Accompany it with the information you received as to the offer |
9143 | to distribute corresponding source code. (This alternative is | |
70b88761 | 9144 | allowed only for noncommercial distribution and only if you |
7463aadd RP |
9145 | received the program in object code or executable form with such |
9146 | an offer, in accord with Subsection b above.) | |
1041a570 | 9147 | @end enumerate |
7463aadd RP |
9148 | |
9149 | The source code for a work means the preferred form of the work for | |
9150 | making modifications to it. For an executable work, complete source | |
9151 | code means all the source code for all modules it contains, plus any | |
9152 | associated interface definition files, plus the scripts used to | |
9153 | control compilation and installation of the executable. However, as a | |
9154 | special exception, the source code distributed need not include | |
9155 | anything that is normally distributed (in either source or binary | |
9156 | form) with the major components (compiler, kernel, and so on) of the | |
9157 | operating system on which the executable runs, unless that component | |
9158 | itself accompanies the executable. | |
9159 | ||
9160 | If distribution of executable or object code is made by offering | |
9161 | access to copy from a designated place, then offering equivalent | |
9162 | access to copy the source code from the same place counts as | |
9163 | distribution of the source code, even though third parties are not | |
9164 | compelled to copy the source along with the object code. | |
70b88761 RP |
9165 | |
9166 | @item | |
7463aadd RP |
9167 | You may not copy, modify, sublicense, or distribute the Program |
9168 | except as expressly provided under this License. Any attempt | |
9169 | otherwise to copy, modify, sublicense or distribute the Program is | |
9170 | void, and will automatically terminate your rights under this License. | |
9171 | However, parties who have received copies, or rights, from you under | |
9172 | this License will not have their licenses terminated so long as such | |
9173 | parties remain in full compliance. | |
70b88761 RP |
9174 | |
9175 | @item | |
7463aadd RP |
9176 | You are not required to accept this License, since you have not |
9177 | signed it. However, nothing else grants you permission to modify or | |
9178 | distribute the Program or its derivative works. These actions are | |
9179 | prohibited by law if you do not accept this License. Therefore, by | |
9180 | modifying or distributing the Program (or any work based on the | |
9181 | Program), you indicate your acceptance of this License to do so, and | |
9182 | all its terms and conditions for copying, distributing or modifying | |
9183 | the Program or works based on it. | |
70b88761 RP |
9184 | |
9185 | @item | |
9186 | Each time you redistribute the Program (or any work based on the | |
7463aadd RP |
9187 | Program), the recipient automatically receives a license from the |
9188 | original licensor to copy, distribute or modify the Program subject to | |
9189 | these terms and conditions. You may not impose any further | |
9190 | restrictions on the recipients' exercise of the rights granted herein. | |
9191 | You are not responsible for enforcing compliance by third parties to | |
9192 | this License. | |
9193 | ||
9194 | @item | |
9195 | If, as a consequence of a court judgment or allegation of patent | |
9196 | infringement or for any other reason (not limited to patent issues), | |
9197 | conditions are imposed on you (whether by court order, agreement or | |
9198 | otherwise) that contradict the conditions of this License, they do not | |
9199 | excuse you from the conditions of this License. If you cannot | |
9200 | distribute so as to satisfy simultaneously your obligations under this | |
9201 | License and any other pertinent obligations, then as a consequence you | |
9202 | may not distribute the Program at all. For example, if a patent | |
9203 | license would not permit royalty-free redistribution of the Program by | |
9204 | all those who receive copies directly or indirectly through you, then | |
9205 | the only way you could satisfy both it and this License would be to | |
9206 | refrain entirely from distribution of the Program. | |
9207 | ||
9208 | If any portion of this section is held invalid or unenforceable under | |
9209 | any particular circumstance, the balance of the section is intended to | |
9210 | apply and the section as a whole is intended to apply in other | |
9211 | circumstances. | |
9212 | ||
9213 | It is not the purpose of this section to induce you to infringe any | |
9214 | patents or other property right claims or to contest validity of any | |
9215 | such claims; this section has the sole purpose of protecting the | |
9216 | integrity of the free software distribution system, which is | |
9217 | implemented by public license practices. Many people have made | |
9218 | generous contributions to the wide range of software distributed | |
9219 | through that system in reliance on consistent application of that | |
9220 | system; it is up to the author/donor to decide if he or she is willing | |
9221 | to distribute software through any other system and a licensee cannot | |
9222 | impose that choice. | |
9223 | ||
9224 | This section is intended to make thoroughly clear what is believed to | |
9225 | be a consequence of the rest of this License. | |
9226 | ||
9227 | @item | |
9228 | If the distribution and/or use of the Program is restricted in | |
9229 | certain countries either by patents or by copyrighted interfaces, the | |
9230 | original copyright holder who places the Program under this License | |
9231 | may add an explicit geographical distribution limitation excluding | |
9232 | those countries, so that distribution is permitted only in or among | |
9233 | countries not thus excluded. In such case, this License incorporates | |
9234 | the limitation as if written in the body of this License. | |
70b88761 RP |
9235 | |
9236 | @item | |
9237 | The Free Software Foundation may publish revised and/or new versions | |
9238 | of the General Public License from time to time. Such new versions will | |
9239 | be similar in spirit to the present version, but may differ in detail to | |
9240 | address new problems or concerns. | |
9241 | ||
9242 | Each version is given a distinguishing version number. If the Program | |
7463aadd | 9243 | specifies a version number of this License which applies to it and ``any |
70b88761 RP |
9244 | later version'', you have the option of following the terms and conditions |
9245 | either of that version or of any later version published by the Free | |
9246 | Software Foundation. If the Program does not specify a version number of | |
7463aadd | 9247 | this License, you may choose any version ever published by the Free Software |
70b88761 RP |
9248 | Foundation. |
9249 | ||
9250 | @item | |
9251 | If you wish to incorporate parts of the Program into other free | |
9252 | programs whose distribution conditions are different, write to the author | |
9253 | to ask for permission. For software which is copyrighted by the Free | |
9254 | Software Foundation, write to the Free Software Foundation; we sometimes | |
9255 | make exceptions for this. Our decision will be guided by the two goals | |
9256 | of preserving the free status of all derivatives of our free software and | |
9257 | of promoting the sharing and reuse of software generally. | |
9258 | ||
9259 | @iftex | |
9260 | @heading NO WARRANTY | |
9261 | @end iftex | |
9262 | @ifinfo | |
9263 | @center NO WARRANTY | |
9264 | @end ifinfo | |
9265 | ||
9266 | @item | |
9267 | BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY | |
9268 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN | |
9269 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES | |
9270 | PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED | |
9271 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
9272 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS | |
9273 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE | |
9274 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, | |
9275 | REPAIR OR CORRECTION. | |
9276 | ||
9277 | @item | |
7463aadd RP |
9278 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING |
9279 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR | |
70b88761 | 9280 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, |
7463aadd RP |
9281 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING |
9282 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED | |
9283 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY | |
9284 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER | |
9285 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE | |
9286 | POSSIBILITY OF SUCH DAMAGES. | |
70b88761 RP |
9287 | @end enumerate |
9288 | ||
9289 | @iftex | |
9290 | @heading END OF TERMS AND CONDITIONS | |
9291 | @end iftex | |
9292 | @ifinfo | |
9293 | @center END OF TERMS AND CONDITIONS | |
9294 | @end ifinfo | |
9295 | ||
9296 | @page | |
54e6b3c3 | 9297 | @unnumberedsec Applying These Terms to Your New Programs |
70b88761 RP |
9298 | |
9299 | If you develop a new program, and you want it to be of the greatest | |
7463aadd RP |
9300 | possible use to the public, the best way to achieve this is to make it |
9301 | free software which everyone can redistribute and change under these terms. | |
70b88761 | 9302 | |
7463aadd RP |
9303 | To do so, attach the following notices to the program. It is safest |
9304 | to attach them to the start of each source file to most effectively | |
9305 | convey the exclusion of warranty; and each file should have at least | |
9306 | the ``copyright'' line and a pointer to where the full notice is found. | |
70b88761 RP |
9307 | |
9308 | @smallexample | |
203eea5d | 9309 | @var{one line to give the program's name and an idea of what it does.} |
70b88761 RP |
9310 | Copyright (C) 19@var{yy} @var{name of author} |
9311 | ||
203eea5d RP |
9312 | This program is free software; you can redistribute it and/or |
9313 | modify it under the terms of the GNU General Public License | |
9314 | as published by the Free Software Foundation; either version 2 | |
9315 | of the License, or (at your option) any later version. | |
70b88761 RP |
9316 | |
9317 | This program is distributed in the hope that it will be useful, | |
9318 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9319 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
9320 | GNU General Public License for more details. | |
9321 | ||
9322 | You should have received a copy of the GNU General Public License | |
203eea5d RP |
9323 | along with this program; if not, write to the |
9324 | Free Software Foundation, Inc., 675 Mass Ave, | |
9325 | Cambridge, MA 02139, USA. | |
70b88761 RP |
9326 | @end smallexample |
9327 | ||
9328 | Also add information on how to contact you by electronic and paper mail. | |
9329 | ||
9330 | If the program is interactive, make it output a short notice like this | |
9331 | when it starts in an interactive mode: | |
9332 | ||
9333 | @smallexample | |
9334 | Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author} | |
203eea5d RP |
9335 | Gnomovision comes with ABSOLUTELY NO WARRANTY; for details |
9336 | type `show w'. This is free software, and you are welcome | |
9337 | to redistribute it under certain conditions; type `show c' | |
9338 | for details. | |
70b88761 RP |
9339 | @end smallexample |
9340 | ||
7463aadd RP |
9341 | The hypothetical commands @samp{show w} and @samp{show c} should show |
9342 | the appropriate parts of the General Public License. Of course, the | |
9343 | commands you use may be called something other than @samp{show w} and | |
9344 | @samp{show c}; they could even be mouse-clicks or menu items---whatever | |
9345 | suits your program. | |
70b88761 RP |
9346 | |
9347 | You should also get your employer (if you work as a programmer) or your | |
9348 | school, if any, to sign a ``copyright disclaimer'' for the program, if | |
9349 | necessary. Here is a sample; alter the names: | |
9350 | ||
1041a570 RP |
9351 | @example |
9352 | Yoyodyne, Inc., hereby disclaims all copyright | |
9353 | interest in the program `Gnomovision' | |
9354 | (which makes passes at compilers) written | |
9355 | by James Hacker. | |
70b88761 RP |
9356 | |
9357 | @var{signature of Ty Coon}, 1 April 1989 | |
9358 | Ty Coon, President of Vice | |
1041a570 | 9359 | @end example |
7463aadd RP |
9360 | |
9361 | This General Public License does not permit incorporating your program into | |
9362 | proprietary programs. If your program is a subroutine library, you may | |
9363 | consider it more useful to permit linking proprietary applications with the | |
9364 | library. If this is what you want to do, use the GNU Library General | |
9365 | Public License instead of this License. | |
18fae2a8 | 9366 | @end ifclear |
70b88761 | 9367 | |
4eb4cf57 | 9368 | @node Index |
d2e08421 | 9369 | @unnumbered Index |
e91b87a3 | 9370 | |
9371 | @printindex cp | |
9372 | ||
fe3f5fc8 RP |
9373 | @tex |
9374 | % I think something like @colophon should be in texinfo. In the | |
9375 | % meantime: | |
9376 | \long\def\colophon{\hbox to0pt{}\vfill | |
9377 | \centerline{The body of this manual is set in} | |
9378 | \centerline{\fontname\tenrm,} | |
9379 | \centerline{with headings in {\bf\fontname\tenbf}} | |
9380 | \centerline{and examples in {\tt\fontname\tentt}.} | |
a6d0b6d3 RP |
9381 | \centerline{{\it\fontname\tenit\/},} |
9382 | \centerline{{\bf\fontname\tenbf}, and} | |
fe3f5fc8 RP |
9383 | \centerline{{\sl\fontname\tensl\/}} |
9384 | \centerline{are used for emphasis.}\vfill} | |
9385 | \page\colophon | |
a6d0b6d3 | 9386 | % Blame: pesch@cygnus.com, 1991. |
fe3f5fc8 RP |
9387 | @end tex |
9388 | ||
e91b87a3 | 9389 | @contents |
9390 | @bye |