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0b302171 | 1 | .\" Copyright (C) 1991, 1999, 2010-2012 Free Software Foundation, Inc. |
c906108c SS |
2 | .\" See section COPYING for conditions for redistribution |
3 | .\" $Id$ | |
87885426 | 4 | .TH gdb 1 "22may2002" "GNU Tools" "GNU Tools" |
c906108c SS |
5 | .SH NAME |
6 | gdb \- The GNU Debugger | |
7 | .SH SYNOPSIS | |
8 | .na | |
9 | .TP | |
10 | .B gdb | |
11 | .RB "[\|" \-help "\|]" | |
07540c15 | 12 | .RB "[\|" \-nh "\|]" |
c906108c SS |
13 | .RB "[\|" \-nx "\|]" |
14 | .RB "[\|" \-q "\|]" | |
15 | .RB "[\|" \-batch "\|]" | |
16 | .RB "[\|" \-cd=\c | |
17 | .I dir\c | |
18 | \|] | |
19 | .RB "[\|" \-f "\|]" | |
20 | .RB "[\|" "\-b\ "\c | |
21 | .IR bps "\|]" | |
22 | .RB "[\|" "\-tty="\c | |
23 | .IR dev "\|]" | |
24 | .RB "[\|" "\-s "\c | |
25 | .I symfile\c | |
26 | \&\|] | |
27 | .RB "[\|" "\-e "\c | |
28 | .I prog\c | |
29 | \&\|] | |
30 | .RB "[\|" "\-se "\c | |
31 | .I prog\c | |
32 | \&\|] | |
33 | .RB "[\|" "\-c "\c | |
34 | .I core\c | |
35 | \&\|] | |
36 | .RB "[\|" "\-x "\c | |
3d16a105 FCE |
37 | .I file\c |
38 | \&\|] | |
39 | .RB "[\|" "\-ex "\c | |
40 | .I cmd\c | |
c906108c SS |
41 | \&\|] |
42 | .RB "[\|" "\-d "\c | |
43 | .I dir\c | |
44 | \&\|] | |
45 | .RB "[\|" \c | |
46 | .I prog\c | |
47 | .RB "[\|" \c | |
48 | .IR core \||\| procID\c | |
49 | \&\|]\&\|] | |
50 | .ad b | |
51 | .SH DESCRIPTION | |
52 | The purpose of a debugger such as GDB is to allow you to see what is | |
53 | going on ``inside'' another program while it executes\(em\&or what another | |
54 | program was doing at the moment it crashed. | |
55 | ||
56 | GDB can do four main kinds of things (plus other things in support of | |
57 | these) to help you catch bugs in the act: | |
58 | ||
59 | .TP | |
60 | \ \ \ \(bu | |
61 | Start your program, specifying anything that might affect its behavior. | |
62 | ||
63 | .TP | |
64 | \ \ \ \(bu | |
65 | Make your program stop on specified conditions. | |
66 | ||
67 | .TP | |
68 | \ \ \ \(bu | |
69 | Examine what has happened, when your program has stopped. | |
70 | ||
71 | .TP | |
72 | \ \ \ \(bu | |
73 | Change things in your program, so you can experiment with correcting the | |
74 | effects of one bug and go on to learn about another. | |
75 | .PP | |
76 | ||
77 | You can use GDB to debug programs written in C, C++, and Modula-2. | |
78 | Fortran support will be added when a GNU Fortran compiler is ready. | |
79 | ||
80 | GDB is invoked with the shell command \c | |
81 | .B gdb\c | |
82 | \&. Once started, it reads | |
83 | commands from the terminal until you tell it to exit with the GDB | |
84 | command \c | |
85 | .B quit\c | |
86 | \&. You can get online help from \c | |
87 | .B gdb\c | |
88 | \& itself | |
89 | by using the command \c | |
90 | .B help\c | |
91 | \&. | |
92 | ||
93 | You can run \c | |
94 | .B gdb\c | |
95 | \& with no arguments or options; but the most | |
96 | usual way to start GDB is with one argument or two, specifying an | |
97 | executable program as the argument: | |
98 | .sp | |
99 | .br | |
100 | gdb\ program | |
101 | .br | |
102 | .sp | |
103 | ||
104 | You can also start with both an executable program and a core file specified: | |
105 | .sp | |
106 | .br | |
107 | gdb\ program\ core | |
108 | .br | |
109 | .sp | |
110 | ||
111 | You can, instead, specify a process ID as a second argument, if you want | |
112 | to debug a running process: | |
113 | .sp | |
114 | .br | |
115 | gdb\ program\ 1234 | |
116 | .br | |
117 | .sp | |
118 | ||
119 | would attach GDB to process \c | |
120 | .B 1234\c | |
121 | \& (unless you also have a file | |
122 | named `\|\c | |
123 | .B 1234\c | |
124 | \&\|'; GDB does check for a core file first). | |
125 | ||
126 | Here are some of the most frequently needed GDB commands: | |
127 | .TP | |
128 | .B break \fR[\|\fIfile\fB:\fR\|]\fIfunction | |
129 | \& | |
130 | Set a breakpoint at \c | |
131 | .I function\c | |
132 | \& (in \c | |
133 | .I file\c | |
134 | \&). | |
135 | .TP | |
136 | .B run \fR[\|\fIarglist\fR\|] | |
137 | Start your program (with \c | |
138 | .I arglist\c | |
139 | \&, if specified). | |
140 | .TP | |
141 | .B bt | |
142 | Backtrace: display the program stack. | |
143 | .TP | |
144 | .BI print " expr"\c | |
145 | \& | |
146 | Display the value of an expression. | |
147 | .TP | |
148 | .B c | |
149 | Continue running your program (after stopping, e.g. at a breakpoint). | |
150 | .TP | |
151 | .B next | |
152 | Execute next program line (after stopping); step \c | |
153 | .I over\c | |
154 | \& any | |
155 | function calls in the line. | |
156 | .TP | |
87885426 FN |
157 | .B edit \fR[\|\fIfile\fB:\fR\|]\fIfunction |
158 | look at the program line where it is presently stopped. | |
159 | .TP | |
160 | .B list \fR[\|\fIfile\fB:\fR\|]\fIfunction | |
161 | type the text of the program in the vicinity of where it is presently stopped. | |
162 | .TP | |
c906108c SS |
163 | .B step |
164 | Execute next program line (after stopping); step \c | |
165 | .I into\c | |
166 | \& any | |
167 | function calls in the line. | |
168 | .TP | |
169 | .B help \fR[\|\fIname\fR\|] | |
170 | Show information about GDB command \c | |
171 | .I name\c | |
172 | \&, or general information | |
173 | about using GDB. | |
174 | .TP | |
175 | .B quit | |
176 | Exit from GDB. | |
177 | .PP | |
178 | For full details on GDB, see \c | |
179 | .I | |
180 | Using GDB: A Guide to the GNU Source-Level Debugger\c | |
181 | \&, by Richard M. Stallman and Roland H. Pesch. The same text is available online | |
182 | as the \c | |
183 | .B gdb\c | |
184 | \& entry in the \c | |
185 | .B info\c | |
186 | \& program. | |
187 | .SH OPTIONS | |
188 | Any arguments other than options specify an executable | |
189 | file and core file (or process ID); that is, the first argument | |
190 | encountered with no | |
191 | associated option flag is equivalent to a `\|\c | |
192 | .B \-se\c | |
193 | \&\|' option, and the | |
194 | second, if any, is equivalent to a `\|\c | |
195 | .B \-c\c | |
196 | \&\|' option if it's the name of a file. Many options have | |
197 | both long and short forms; both are shown here. The long forms are also | |
198 | recognized if you truncate them, so long as enough of the option is | |
199 | present to be unambiguous. (If you prefer, you can flag option | |
200 | arguments with `\|\c | |
201 | .B +\c | |
202 | \&\|' rather than `\|\c | |
203 | .B \-\c | |
204 | \&\|', though we illustrate the | |
205 | more usual convention.) | |
206 | ||
207 | All the options and command line arguments you give are processed | |
208 | in sequential order. The order makes a difference when the | |
209 | `\|\c | |
210 | .B \-x\c | |
211 | \&\|' option is used. | |
212 | ||
213 | .TP | |
214 | .B \-help | |
215 | .TP | |
216 | .B \-h | |
217 | List all options, with brief explanations. | |
218 | ||
219 | .TP | |
220 | .BI "\-symbols=" "file"\c | |
221 | .TP | |
222 | .BI "\-s " "file"\c | |
223 | \& | |
224 | Read symbol table from file \c | |
225 | .I file\c | |
226 | \&. | |
227 | ||
228 | .TP | |
229 | .B \-write | |
230 | Enable writing into executable and core files. | |
231 | ||
232 | .TP | |
233 | .BI "\-exec=" "file"\c | |
234 | .TP | |
235 | .BI "\-e " "file"\c | |
236 | \& | |
237 | Use file \c | |
238 | .I file\c | |
239 | \& as the executable file to execute when | |
240 | appropriate, and for examining pure data in conjunction with a core | |
241 | dump. | |
242 | ||
243 | .TP | |
244 | .BI "\-se=" "file"\c | |
245 | \& | |
246 | Read symbol table from file \c | |
247 | .I file\c | |
248 | \& and use it as the executable | |
249 | file. | |
250 | ||
251 | .TP | |
252 | .BI "\-core=" "file"\c | |
253 | .TP | |
254 | .BI "\-c " "file"\c | |
255 | \& | |
256 | Use file \c | |
257 | .I file\c | |
258 | \& as a core dump to examine. | |
259 | ||
260 | .TP | |
261 | .BI "\-command=" "file"\c | |
262 | .TP | |
263 | .BI "\-x " "file"\c | |
264 | \& | |
265 | Execute GDB commands from file \c | |
266 | .I file\c | |
267 | \&. | |
268 | ||
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269 | .TP |
270 | .BI "\-ex " "command"\c | |
271 | \& | |
272 | Execute given GDB \c | |
273 | .I command\c | |
274 | \&. | |
275 | ||
c906108c SS |
276 | .TP |
277 | .BI "\-directory=" "directory"\c | |
278 | .TP | |
279 | .BI "\-d " "directory"\c | |
280 | \& | |
281 | Add \c | |
282 | .I directory\c | |
283 | \& to the path to search for source files. | |
284 | .PP | |
285 | ||
07540c15 DE |
286 | .TP |
287 | .B \-nh | |
288 | Do not execute commands from ~/.gdbinit. | |
289 | ||
c906108c SS |
290 | .TP |
291 | .B \-nx | |
292 | .TP | |
293 | .B \-n | |
294 | Do not execute commands from any `\|\c | |
295 | .B .gdbinit\c | |
296 | \&\|' initialization files. | |
c906108c SS |
297 | |
298 | ||
299 | .TP | |
300 | .B \-quiet | |
301 | .TP | |
302 | .B \-q | |
303 | ``Quiet''. Do not print the introductory and copyright messages. These | |
304 | messages are also suppressed in batch mode. | |
305 | ||
306 | .TP | |
307 | .B \-batch | |
308 | Run in batch mode. Exit with status \c | |
309 | .B 0\c | |
310 | \& after processing all the command | |
311 | files specified with `\|\c | |
312 | .B \-x\c | |
313 | \&\|' (and `\|\c | |
314 | .B .gdbinit\c | |
315 | \&\|', if not inhibited). | |
316 | Exit with nonzero status if an error occurs in executing the GDB | |
317 | commands in the command files. | |
318 | ||
319 | Batch mode may be useful for running GDB as a filter, for example to | |
320 | download and run a program on another computer; in order to make this | |
321 | more useful, the message | |
322 | .sp | |
323 | .br | |
324 | Program\ exited\ normally. | |
325 | .br | |
326 | .sp | |
327 | ||
328 | (which is ordinarily issued whenever a program running under GDB control | |
329 | terminates) is not issued when running in batch mode. | |
330 | ||
331 | .TP | |
332 | .BI "\-cd=" "directory"\c | |
333 | \& | |
334 | Run GDB using \c | |
335 | .I directory\c | |
336 | \& as its working directory, | |
337 | instead of the current directory. | |
338 | ||
339 | .TP | |
340 | .B \-fullname | |
341 | .TP | |
342 | .B \-f | |
343 | Emacs sets this option when it runs GDB as a subprocess. It tells GDB | |
344 | to output the full file name and line number in a standard, | |
345 | recognizable fashion each time a stack frame is displayed (which | |
346 | includes each time the program stops). This recognizable format looks | |
347 | like two `\|\c | |
348 | .B \032\c | |
349 | \&\|' characters, followed by the file name, line number | |
350 | and character position separated by colons, and a newline. The | |
351 | Emacs-to-GDB interface program uses the two `\|\c | |
352 | .B \032\c | |
353 | \&\|' characters as | |
354 | a signal to display the source code for the frame. | |
355 | ||
356 | .TP | |
357 | .BI "\-b " "bps"\c | |
358 | \& | |
359 | Set the line speed (baud rate or bits per second) of any serial | |
360 | interface used by GDB for remote debugging. | |
361 | ||
362 | .TP | |
363 | .BI "\-tty=" "device"\c | |
364 | \& | |
365 | Run using \c | |
366 | .I device\c | |
367 | \& for your program's standard input and output. | |
368 | .PP | |
369 | ||
370 | .SH "SEE ALSO" | |
f4045bcb PA |
371 | The full documentation for |
372 | .B gdb | |
373 | is maintained as a Texinfo manual. If the | |
374 | .B info | |
375 | and | |
376 | .B gdb | |
377 | programs and GDB's Texinfo documentation are properly installed at | |
378 | your site, the command | |
379 | .IP | |
380 | .B info gdb | |
381 | .PP | |
382 | should give you access to the complete manual. | |
383 | ||
c906108c SS |
384 | .I |
385 | Using GDB: A Guide to the GNU Source-Level Debugger\c | |
386 | , Richard M. Stallman and Roland H. Pesch, July 1991. | |
387 | .SH COPYING | |
abd775ce | 388 | Copyright (c) 1991, 2010 Free Software Foundation, Inc. |
c906108c SS |
389 | .PP |
390 | Permission is granted to make and distribute verbatim copies of | |
391 | this manual provided the copyright notice and this permission notice | |
392 | are preserved on all copies. | |
393 | .PP | |
394 | Permission is granted to copy and distribute modified versions of this | |
395 | manual under the conditions for verbatim copying, provided that the | |
396 | entire resulting derived work is distributed under the terms of a | |
397 | permission notice identical to this one. | |
398 | .PP | |
399 | Permission is granted to copy and distribute translations of this | |
400 | manual into another language, under the above conditions for modified | |
401 | versions, except that this permission notice may be included in | |
402 | translations approved by the Free Software Foundation instead of in | |
403 | the original English. |