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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
b65d8176 TTN |
2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, |
3 | @c 2002, 2003, 2004, 2005 Free Software Foundation, Inc. | |
6bf7aab6 | 4 | @c See file emacs.texi for copying conditions. |
ffb1af2b | 5 | @node Building, Maintaining, Programs, Top |
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6 | @chapter Compiling and Testing Programs |
7 | @cindex building programs | |
8 | @cindex program building | |
9 | @cindex running Lisp functions | |
10 | ||
11 | The previous chapter discusses the Emacs commands that are useful for | |
12 | making changes in programs. This chapter deals with commands that assist | |
13 | in the larger process of developing and maintaining programs. | |
14 | ||
15 | @menu | |
16 | * Compilation:: Compiling programs in languages other | |
17 | than Lisp (C, Pascal, etc.). | |
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18 | * Compilation Mode:: The mode for visiting compiler errors. |
19 | * Compilation Shell:: Customizing your shell properly | |
20 | for use in the compilation buffer. | |
ed4389af | 21 | * Grep Searching:: Searching with grep. |
ff994d96 | 22 | * Flymake:: Finding syntax errors on the fly. |
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23 | * Debuggers:: Running symbolic debuggers for non-Lisp programs. |
24 | * Executing Lisp:: Various modes for editing Lisp programs, | |
6bf7aab6 | 25 | with different facilities for running |
177c0ea7 | 26 | the Lisp programs. |
6bf7aab6 | 27 | * Libraries: Lisp Libraries. Creating Lisp programs to run in Emacs. |
6bf7aab6 | 28 | * Eval: Lisp Eval. Executing a single Lisp expression in Emacs. |
254196f5 | 29 | * Interaction: Lisp Interaction. Executing Lisp in an Emacs buffer. |
177c0ea7 | 30 | * External Lisp:: Communicating through Emacs with a separate Lisp. |
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31 | @end menu |
32 | ||
33 | @node Compilation | |
34 | @section Running Compilations under Emacs | |
35 | @cindex inferior process | |
36 | @cindex make | |
37 | @cindex compilation errors | |
38 | @cindex error log | |
39 | ||
40 | Emacs can run compilers for noninteractive languages such as C and | |
41 | Fortran as inferior processes, feeding the error log into an Emacs buffer. | |
42 | It can also parse the error messages and show you the source lines where | |
43 | compilation errors occurred. | |
44 | ||
45 | @table @kbd | |
46 | @item M-x compile | |
74b1aac1 | 47 | Run a compiler asynchronously under Emacs, with error messages going to |
58fa012d | 48 | the @samp{*compilation*} buffer. |
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49 | @item M-x recompile |
50 | Invoke a compiler with the same command as in the last invocation of | |
51 | @kbd{M-x compile}. | |
6bf7aab6 | 52 | @item M-x kill-compilation |
b00d98ed | 53 | Kill the running compilation subprocess. |
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54 | @end table |
55 | ||
56 | @findex compile | |
57 | To run @code{make} or another compilation command, do @kbd{M-x | |
58 | compile}. This command reads a shell command line using the minibuffer, | |
59 | and then executes the command in an inferior shell, putting output in | |
60 | the buffer named @samp{*compilation*}. The current buffer's default | |
61 | directory is used as the working directory for the execution of the | |
62 | command; normally, therefore, the compilation happens in this | |
63 | directory. | |
64 | ||
65 | @vindex compile-command | |
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66 | The default for the compilation command is normally @samp{make -k}, |
67 | which is correct most of the time for nontrivial programs. | |
68 | (@xref{Top,, Make, make, GNU Make Manual}.) If you have done @kbd{M-x | |
69 | compile} before, the default each time is the command you used the | |
70 | previous time. @code{compile} stores this command in the variable | |
71 | @code{compile-command}, so setting that variable specifies the default | |
72 | for the next use of @kbd{M-x compile}. If a file specifies a file | |
73 | local value for @code{compile-command}, that provides the default when | |
74 | you type @kbd{M-x compile} in that file's buffer. @xref{File | |
75 | Variables}. | |
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76 | |
77 | Starting a compilation displays the buffer @samp{*compilation*} in | |
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78 | another window but does not select it. The buffer's mode line tells |
79 | you whether compilation is finished, with the word @samp{run}, | |
80 | @samp{signal} or @samp{exit} inside the parentheses. You do not have | |
81 | to keep this buffer visible; compilation continues in any case. While | |
82 | a compilation is going on, the string @samp{Compiling} appears in the | |
83 | mode lines of all windows. When this string disappears, the | |
84 | compilation is finished. | |
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85 | |
86 | If you want to watch the compilation transcript as it appears, switch | |
87 | to the @samp{*compilation*} buffer and move point to the end of the | |
88 | buffer. When point is at the end, new compilation output is inserted | |
89 | above point, which remains at the end. If point is not at the end of | |
90 | the buffer, it remains fixed while more compilation output is added at | |
91 | the end of the buffer. | |
92 | ||
09e58ba6 | 93 | @cindex compilation buffer, keeping current position at the end |
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94 | @vindex compilation-scroll-output |
95 | If you set the variable @code{compilation-scroll-output} to a | |
96 | non-@code{nil} value, then the compilation buffer always scrolls to | |
97 | follow output as it comes in. | |
98 | ||
99 | @findex kill-compilation | |
43b4d3c0 | 100 | When the compiler process terminates, for whatever reason, the mode |
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101 | line of the @samp{*compilation*} buffer changes to say @samp{exit} |
102 | (followed by the exit code, @samp{[0]} for a normal exit), or | |
103 | @samp{signal} (if a signal terminated the process), instead of | |
104 | @samp{run}. Starting a new compilation also kills any running | |
105 | compilation, as only one can exist at any time. However, @kbd{M-x | |
106 | compile} asks for confirmation before actually killing a compilation | |
107 | that is running. You can also kill the compilation process with | |
108 | @kbd{M-x kill-compilation}. | |
6bf7aab6 | 109 | |
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110 | @findex recompile |
111 | To rerun the last compilation with the same command, type @kbd{M-x | |
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112 | recompile}. This automatically reuses the compilation command from |
113 | the last invocation of @kbd{M-x compile}. It also reuses the | |
114 | @samp{*compilation*} buffer and starts the compilation in its default | |
115 | directory, which is the directory in which the previous compilation | |
116 | was started. | |
9ee31341 | 117 | |
43b4d3c0 | 118 | Emacs does not expect a compiler process to launch asynchronous |
266e712e | 119 | subprocesses; if it does, and they keep running after the main |
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120 | compiler process has terminated, Emacs may kill them or their output |
121 | may not arrive in Emacs. To avoid this problem, make the main process | |
122 | wait for its subprocesses to finish. In a shell script, you can do this | |
123 | using @samp{$!} and @samp{wait}, like this: | |
124 | ||
125 | @example | |
126 | (sleep 10; echo 2nd)& pid=$! # @r{Record pid of subprocess} | |
127 | echo first message | |
128 | wait $pid # @r{Wait for subprocess} | |
129 | @end example | |
266e712e | 130 | |
9cad1898 RS |
131 | If the background process does not output to the compilation buffer, |
132 | so you only need to prevent it from being killed when the main | |
133 | compilation process terminates, this is sufficient: | |
134 | ||
135 | @example | |
136 | nohup @var{command}; sleep 1 | |
137 | @end example | |
138 | ||
139 | @vindex compilation-environment | |
140 | You can control the environment passed to the compilation command | |
141 | with the variable @code{compilation-environment}. Its value is a list | |
142 | of environment variable settings; each element should be a string of | |
143 | the form @code{"@var{envvarname}=@var{value}"}. These environment | |
144 | variable settings override the usual ones. | |
145 | ||
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146 | @node Compilation Mode |
147 | @section Compilation Mode | |
148 | ||
149 | @findex compile-goto-error | |
150 | @cindex Compilation mode | |
151 | @cindex mode, Compilation | |
152 | The @samp{*compilation*} buffer uses a special major mode, Compilation | |
153 | mode, whose main feature is to provide a convenient way to look at the | |
154 | source line where the error happened. | |
155 | ||
156 | @table @kbd | |
089ed565 KS |
157 | @item M-g M-n |
158 | @itemx M-g n | |
159 | @itemx C-x ` | |
6bf7aab6 | 160 | Visit the locus of the next compiler error message or @code{grep} match. |
089ed565 KS |
161 | @item M-g M-p |
162 | @itemx M-g p | |
163 | Visit the locus of the previous compiler error message or @code{grep} match. | |
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164 | @item @key{RET} |
165 | Visit the locus of the error message that point is on. | |
166 | This command is used in the compilation buffer. | |
167 | @item Mouse-2 | |
168 | Visit the locus of the error message that you click on. | |
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169 | @item M-n |
170 | Find and highlight the locus of the next error message, without | |
171 | selecting the source buffer. | |
172 | @item M-p | |
173 | Find and highlight the locus of the previous error message, without | |
174 | selecting the source buffer. | |
175 | @item M-@} | |
176 | Move point to the next error for a different file than the current | |
177 | one. | |
178 | @item M-@{ | |
179 | Move point to the previous error for a different file than the current | |
180 | one. | |
181 | @item C-c C-f | |
182 | Toggle Next Error Follow minor mode, which makes cursor motion in the | |
183 | compilation buffer produce automatic source display. | |
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184 | @end table |
185 | ||
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186 | @kindex M-g M-n |
187 | @kindex M-g n | |
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188 | @kindex C-x ` |
189 | @findex next-error | |
190 | You can visit the source for any particular error message by moving | |
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191 | point in the @samp{*compilation*} buffer to that error message and |
192 | typing @key{RET} (@code{compile-goto-error}). Alternatively, you can | |
193 | click @kbd{Mouse-2} on the error message; you need not switch to the | |
194 | @samp{*compilation*} buffer first. | |
6bf7aab6 | 195 | |
ed4389af | 196 | @vindex next-error-highlight |
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197 | To parse the compiler error messages sequentially, type @kbd{C-x `} |
198 | (@code{next-error}). The character following the @kbd{C-x} is the | |
199 | backquote or ``grave accent,'' not the single-quote. This command is | |
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200 | available in all buffers, not just in @samp{*compilation*}; it |
201 | displays the next error message at the top of one window and source | |
202 | location of the error in another window. It also momentarily | |
203 | highlights the relevant source line. You can change the behavior of | |
204 | this highlighting with the variable @code{next-error-highlight}. | |
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205 | |
206 | The first time @kbd{C-x `} is used after the start of a compilation, | |
207 | it moves to the first error's location. Subsequent uses of @kbd{C-x `} | |
208 | advance down to subsequent errors. If you visit a specific error | |
209 | message with @key{RET} or @kbd{Mouse-2}, subsequent @kbd{C-x `} | |
210 | commands advance from there. When @kbd{C-x `} gets to the end of the | |
211 | buffer and finds no more error messages to visit, it fails and signals | |
212 | an Emacs error. | |
213 | ||
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214 | @vindex compilation-skip-threshold |
215 | By default, @kbd{C-x `} skips less important messages. The variable | |
216 | @code{compilation-skip-threshold} controls this. If its value is 2, | |
217 | @kbd{C-x `} skips anything less than error, 1 skips anything less | |
218 | than warning, and 0 doesn't skip any messages. | |
219 | ||
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220 | When the left fringe is displayed, an arrow points to the |
221 | current message in the compilation buffer. The variable | |
222 | @code{compilation-context-lines} controls the number of lines of | |
223 | leading context in the window before the current message. If it is | |
224 | @code{nil} and the left fringe is displayed, the window doesn't | |
225 | scroll. If there is no left fringe, no arrow is displayed and a value | |
226 | of @code{nil} means display the message at the top of the window. | |
227 | ||
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228 | If you're not in the compilation buffer when you run |
229 | @code{next-error}, Emacs will look for a buffer that contains error | |
230 | messages. First, it looks for one displayed in the selected frame, | |
231 | then for one that previously had @code{next-error} called on it, and | |
232 | then at the current buffer. Finally, Emacs looks at all the remaining | |
233 | buffers. @code{next-error} signals an error if it can't find any such | |
234 | buffer. | |
235 | ||
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236 | @kbd{C-u C-x `} starts scanning from the beginning of the compilation |
237 | buffer. This is one way to process the same set of errors again. | |
238 | ||
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239 | @vindex compilation-error-regexp-alist |
240 | @vindex grep-regexp-alist | |
241 | To parse messages from the compiler, Compilation mode uses the | |
242 | variable @code{compilation-error-regexp-alist} which lists various | |
243 | formats of error messages and tells Emacs how to extract the source file | |
244 | and the line number from the text of a message. If your compiler isn't | |
245 | supported, you can tailor Compilation mode to it by adding elements to | |
246 | that list. A similar variable @code{grep-regexp-alist} tells Emacs how | |
247 | to parse output of a @code{grep} command. | |
248 | ||
ed4389af RS |
249 | @findex compilation-next-error |
250 | @findex compilation-previous-error | |
251 | @findex compilation-next-file | |
252 | @findex compilation-previous-file | |
6bf7aab6 | 253 | Compilation mode also redefines the keys @key{SPC} and @key{DEL} to |
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254 | scroll by screenfuls, and @kbd{M-n} (@code{compilation-next-error}) |
255 | and @kbd{M-p} (@code{compilation-previous-error}) to move to the next | |
256 | or previous error message. You can also use @kbd{M-@{} | |
257 | (@code{compilation-next-file} and @kbd{M-@}} | |
258 | (@code{compilation-previous-file}) to move up or down to an error | |
259 | message for a different source file. | |
260 | ||
261 | @cindex Next Error Follow mode | |
262 | @findex next-error-follow-minor-mode | |
263 | You can type @kbd{C-c C-f} to toggle Next Error Follow mode. In | |
264 | this minor mode, ordinary cursor motion in the compilation buffer | |
265 | automatically updates the source buffer. For instance, moving the | |
266 | cursor to the next error message causes the location of that error to | |
267 | be displayed immediately. | |
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268 | |
269 | The features of Compilation mode are also available in a minor mode | |
270 | called Compilation Minor mode. This lets you parse error messages in | |
271 | any buffer, not just a normal compilation output buffer. Type @kbd{M-x | |
272 | compilation-minor-mode} to enable the minor mode. This defines the keys | |
273 | @key{RET} and @kbd{Mouse-2}, as in the Compilation major mode. | |
274 | ||
275 | Compilation minor mode works in any buffer, as long as the contents | |
276 | are in a format that it understands. In an Rlogin buffer (@pxref{Remote | |
277 | Host}), Compilation minor mode automatically accesses remote source | |
278 | files by FTP (@pxref{File Names}). | |
279 | ||
280 | @node Compilation Shell | |
281 | @section Subshells for Compilation | |
282 | ||
283 | Emacs uses a shell to run the compilation command, but specifies | |
284 | the option for a noninteractive shell. This means, in particular, that | |
285 | the shell should start with no prompt. If you find your usual shell | |
286 | prompt making an unsightly appearance in the @samp{*compilation*} | |
287 | buffer, it means you have made a mistake in your shell's init file by | |
288 | setting the prompt unconditionally. (This init file's name may be | |
289 | @file{.bashrc}, @file{.profile}, @file{.cshrc}, @file{.shrc}, or various | |
290 | other things, depending on the shell you use.) The shell init file | |
291 | should set the prompt only if there already is a prompt. In csh, here | |
292 | is how to do it: | |
293 | ||
294 | @example | |
295 | if ($?prompt) set prompt = @dots{} | |
296 | @end example | |
297 | ||
298 | @noindent | |
299 | And here's how to do it in bash: | |
300 | ||
301 | @example | |
302 | if [ "$@{PS1+set@}" = set ] | |
303 | then PS1=@dots{} | |
304 | fi | |
305 | @end example | |
306 | ||
307 | There may well be other things that your shell's init file | |
308 | ought to do only for an interactive shell. You can use the same | |
309 | method to conditionalize them. | |
310 | ||
311 | The MS-DOS ``operating system'' does not support asynchronous | |
312 | subprocesses; to work around this lack, @kbd{M-x compile} runs the | |
313 | compilation command synchronously on MS-DOS. As a consequence, you must | |
314 | wait until the command finishes before you can do anything else in | |
315 | Emacs. @xref{MS-DOS}. | |
316 | ||
ed4389af RS |
317 | @node Grep Searching |
318 | @section Searching with Grep under Emacs | |
319 | ||
ed4389af | 320 | Just as you can run a compiler from Emacs and then visit the lines |
869d986e | 321 | with compilation errors, you can also run @code{grep} and |
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322 | then visit the lines on which matches were found. This works by |
323 | treating the matches reported by @code{grep} as if they were ``errors.'' | |
324 | ||
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325 | @table @kbd |
326 | @item M-x grep | |
327 | Run @code{grep} asynchronously under Emacs, with matching lines | |
328 | listed in the buffer named @samp{*grep*}. | |
329 | @item M-x grep-find | |
330 | @itemx M-x find-grep | |
331 | Run @code{grep} via @code{find}, with user-specified arguments, and | |
332 | collect output in the buffer named @samp{*grep*}. | |
333 | @item M-x kill-grep | |
334 | Kill the running @code{grep} subprocess. | |
335 | @end table | |
336 | ||
337 | @findex grep | |
338 | To run @code{grep}, type @kbd{M-x grep}, then enter a command line that | |
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339 | specifies how to run @code{grep}. Use the same arguments you would give |
340 | @code{grep} when running it normally: a @code{grep}-style regexp | |
341 | (usually in single-quotes to quote the shell's special characters) | |
342 | followed by file names, which may use wildcards. If you specify a | |
343 | prefix argument for @kbd{M-x grep}, it figures out the tag | |
344 | (@pxref{Tags}) around point, and puts that into the default | |
345 | @code{grep} command. | |
346 | ||
347 | The output from @code{grep} goes in the @samp{*grep*} buffer. You | |
348 | can find the corresponding lines in the original files using @kbd{C-x | |
349 | `}, @key{RET}, and so forth, just like compilation errors. | |
350 | ||
351 | Some grep programs accept a @samp{--color} option to output special | |
352 | markers around matches for the purpose of highlighting. You can make | |
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353 | use of this feature by setting @code{grep-highlight-matches} to |
354 | @code{t}. When displaying a match in the source buffer, the exact | |
355 | match will be highlighted, instead of the entire source line. | |
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356 | |
357 | @findex grep-find | |
358 | @findex find-grep | |
359 | The command @kbd{M-x grep-find} (also available as @kbd{M-x | |
360 | find-grep}) is similar to @kbd{M-x grep}, but it supplies a different | |
361 | initial default for the command---one that runs both @code{find} and | |
362 | @code{grep}, so as to search every file in a directory tree. See also | |
363 | the @code{find-grep-dired} command, in @ref{Dired and Find}. | |
364 | ||
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365 | @node Flymake |
366 | @section Finding Syntax Errors On The Fly | |
367 | @cindex checking syntax | |
368 | ||
369 | Flymake mode is a minor mode that performs on-the-fly syntax | |
370 | checking for many programming and markup languages, including C, C++, | |
371 | Perl, HTML, and @TeX{}/La@TeX{}. It is somewhat analogous to Flyspell | |
372 | mode, which performs spell checking for ordinary human languages in a | |
373 | similar fashion (@pxref{Spelling}). As you edit a file, Flymake mode | |
374 | runs an appropriate syntax checking tool in the background, using a | |
375 | temporary copy of the buffer. It then parses the error and warning | |
376 | messages, and highlights the erroneous lines in the buffer. The | |
377 | syntax checking tool used depends on the language; for example, for | |
378 | C/C++ files this is usually the C compiler. Flymake can also use | |
379 | build tools such as @code{make} for checking complicated projects. | |
380 | ||
381 | To activate Flymake mode, type @kbd{M-x flymake-mode}. You can move | |
382 | to the errors spotted by Flymake mode with @kbd{M-x | |
383 | flymake-goto-next-error} and @kbd{M-x flymake-goto-prev-error}. To | |
384 | display any error messages associated with the current line, use | |
385 | @kbd{M-x flymake-display-err-menu-for-current-line}. | |
386 | ||
387 | For more details about using Flymake, see @ref{Top, Flymake, | |
388 | Flymake, flymake, The Flymake Manual}. | |
389 | ||
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390 | @node Debuggers |
391 | @section Running Debuggers Under Emacs | |
392 | @cindex debuggers | |
393 | @cindex GUD library | |
394 | @cindex GDB | |
395 | @cindex DBX | |
396 | @cindex SDB | |
397 | @cindex XDB | |
398 | @cindex Perldb | |
ed4389af | 399 | @cindex bashdb |
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400 | @cindex JDB |
401 | @cindex PDB | |
402 | ||
403 | @c Do you believe in GUD? | |
404 | The GUD (Grand Unified Debugger) library provides an interface to | |
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405 | various symbolic debuggers from within Emacs. We recommend the |
406 | debugger GDB, which is free software, but you can also run DBX, SDB or | |
407 | XDB if you have them. GUD can also serve as an interface to Perl's | |
408 | debugging mode, the Python debugger PDB, the bash debugger, and to | |
409 | JDB, the Java Debugger. @xref{Debugging,, The Lisp Debugger, elisp, | |
410 | the Emacs Lisp Reference Manual}, for information on debugging Emacs | |
411 | Lisp programs. | |
6bf7aab6 DL |
412 | |
413 | @menu | |
414 | * Starting GUD:: How to start a debugger subprocess. | |
415 | * Debugger Operation:: Connection between the debugger and source buffers. | |
416 | * Commands of GUD:: Key bindings for common commands. | |
417 | * GUD Customization:: Defining your own commands for GUD. | |
f9ad161b RS |
418 | * GDB Graphical Interface:: An enhanced mode that uses GDB features to |
419 | implement a graphical debugging environment through | |
420 | Emacs. | |
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421 | @end menu |
422 | ||
423 | @node Starting GUD | |
424 | @subsection Starting GUD | |
425 | ||
426 | There are several commands for starting a debugger, each corresponding | |
427 | to a particular debugger program. | |
428 | ||
429 | @table @kbd | |
430 | @item M-x gdb @key{RET} @var{file} @key{RET} | |
431 | @findex gdb | |
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432 | Run GDB as a subprocess of Emacs. By default, this operates in |
433 | graphical mode; @xref{GDB Graphical Interface}. Graphical mode | |
434 | does not support any other debuggers. | |
f9ad161b | 435 | |
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436 | @item M-x dbx @key{RET} @var{file} @key{RET} |
437 | @findex dbx | |
4125ceb0 | 438 | Similar, but run DBX instead of GDB. |
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439 | |
440 | @item M-x xdb @key{RET} @var{file} @key{RET} | |
441 | @findex xdb | |
442 | @vindex gud-xdb-directories | |
4125ceb0 | 443 | Similar, but run XDB instead of GDB. Use the variable |
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444 | @code{gud-xdb-directories} to specify directories to search for source |
445 | files. | |
446 | ||
447 | @item M-x sdb @key{RET} @var{file} @key{RET} | |
448 | @findex sdb | |
4125ceb0 | 449 | Similar, but run SDB instead of GDB. |
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450 | |
451 | Some versions of SDB do not mention source file names in their | |
452 | messages. When you use them, you need to have a valid tags table | |
453 | (@pxref{Tags}) in order for GUD to find functions in the source code. | |
454 | If you have not visited a tags table or the tags table doesn't list one | |
455 | of the functions, you get a message saying @samp{The sdb support | |
456 | requires a valid tags table to work}. If this happens, generate a valid | |
457 | tags table in the working directory and try again. | |
458 | ||
ed4389af RS |
459 | @item M-x bashdb @key{RET} @var{file} @key{RET} |
460 | @findex bashdb | |
461 | Run the bash debugger to debug @var{file}, a shell script. | |
462 | ||
6bf7aab6 DL |
463 | @item M-x perldb @key{RET} @var{file} @key{RET} |
464 | @findex perldb | |
465 | Run the Perl interpreter in debug mode to debug @var{file}, a Perl program. | |
466 | ||
467 | @item M-x jdb @key{RET} @var{file} @key{RET} | |
468 | @findex jdb | |
469 | Run the Java debugger to debug @var{file}. | |
470 | ||
471 | @item M-x pdb @key{RET} @var{file} @key{RET} | |
472 | @findex pdb | |
473 | Run the Python debugger to debug @var{file}. | |
474 | @end table | |
475 | ||
476 | Each of these commands takes one argument: a command line to invoke | |
477 | the debugger. In the simplest case, specify just the name of the | |
478 | executable file you want to debug. You may also use options that the | |
479 | debugger supports. However, shell wildcards and variables are not | |
480 | allowed. GUD assumes that the first argument not starting with a | |
481 | @samp{-} is the executable file name. | |
482 | ||
6bf7aab6 DL |
483 | @node Debugger Operation |
484 | @subsection Debugger Operation | |
485 | ||
3605e23f | 486 | @cindex fringes, and current execution line in GUD |
6bf7aab6 DL |
487 | When you run a debugger with GUD, the debugger uses an Emacs buffer |
488 | for its ordinary input and output. This is called the GUD buffer. The | |
489 | debugger displays the source files of the program by visiting them in | |
490 | Emacs buffers. An arrow (@samp{=>}) in one of these buffers indicates | |
8643647c RS |
491 | the current execution line.@footnote{Under a window system, the arrow |
492 | appears in the left fringe of the Emacs window.} Moving point in this | |
493 | buffer does not move the arrow. | |
6bf7aab6 DL |
494 | |
495 | You can start editing these source files at any time in the buffers | |
58fa012d | 496 | that display them. The arrow is not part of the file's |
6bf7aab6 DL |
497 | text; it appears only on the screen. If you do modify a source file, |
498 | keep in mind that inserting or deleting lines will throw off the arrow's | |
499 | positioning; GUD has no way of figuring out which line corresponded | |
500 | before your changes to the line number in a debugger message. Also, | |
501 | you'll typically have to recompile and restart the program for your | |
502 | changes to be reflected in the debugger's tables. | |
503 | ||
504 | If you wish, you can control your debugger process entirely through the | |
505 | debugger buffer, which uses a variant of Shell mode. All the usual | |
506 | commands for your debugger are available, and you can use the Shell mode | |
507 | history commands to repeat them. @xref{Shell Mode}. | |
508 | ||
499de9ba RS |
509 | @cindex tooltips with GUD |
510 | @vindex tooltip-gud-modes | |
c2332b4f NR |
511 | @vindex gud-tooltip-mode |
512 | @vindex gud-tooltip-echo-area | |
499de9ba | 513 | The Tooltip facility (@pxref{Tooltips}) provides support for GUD@. |
8a25d51a NR |
514 | You activate this feature by turning on the minor mode |
515 | @code{gud-tooltip-mode}. Then you can display a variable's value in a | |
516 | tooltip simply by pointing at it with the mouse. In graphical mode, | |
517 | with a C program, you can also display the @code{#define} directive | |
518 | associated with an identifier when the program is not executing. This | |
519 | operates in the GUD buffer and in source buffers with major modes in | |
c2332b4f | 520 | the list @code{gud-tooltip-modes}. If the variable |
cb7b02c7 NR |
521 | @code{gud-tooltip-echo-area} is non-@code{nil} then the variable's |
522 | value is displayed in the echo area. | |
499de9ba | 523 | |
b376642d NR |
524 | With GDB in text command mode (@pxref{GDB Graphical Interface}), |
525 | it is possible that use of GUD tooltips can cause a function to be | |
526 | called with harmful side-effects. In this case, Emacs disables | |
dd6700eb | 527 | them. |
b376642d | 528 | |
6bf7aab6 DL |
529 | @node Commands of GUD |
530 | @subsection Commands of GUD | |
531 | ||
532 | The GUD interaction buffer uses a variant of Shell mode, so the | |
533 | commands of Shell mode are available (@pxref{Shell Mode}). GUD mode | |
534 | also provides commands for setting and clearing breakpoints, for | |
535 | selecting stack frames, and for stepping through the program. These | |
536 | commands are available both in the GUD buffer and globally, but with | |
cb7b02c7 | 537 | different key bindings. It also has its own tool bar from which you |
8d66c08b NR |
538 | can invoke the more common commands by clicking on the appropriate |
539 | icon. This is particularly useful for repetitive commands like | |
540 | gud-next and gud-step and allows the user to hide the GUD buffer. | |
6bf7aab6 | 541 | |
58fa012d EZ |
542 | The breakpoint commands are normally used in source file buffers, |
543 | because that is the easiest way to specify where to set or clear the | |
544 | breakpoint. Here's the global command to set a breakpoint: | |
6bf7aab6 DL |
545 | |
546 | @table @kbd | |
547 | @item C-x @key{SPC} | |
548 | @kindex C-x SPC | |
549 | Set a breakpoint on the source line that point is on. | |
550 | @end table | |
551 | ||
552 | @kindex C-x C-a @r{(GUD)} | |
553 | Here are the other special commands provided by GUD. The keys | |
554 | starting with @kbd{C-c} are available only in the GUD interaction | |
555 | buffer. The key bindings that start with @kbd{C-x C-a} are available in | |
556 | the GUD interaction buffer and also in source files. | |
557 | ||
558 | @table @kbd | |
559 | @item C-c C-l | |
560 | @kindex C-c C-l @r{(GUD)} | |
561 | @itemx C-x C-a C-l | |
562 | @findex gud-refresh | |
563 | Display in another window the last line referred to in the GUD | |
564 | buffer (that is, the line indicated in the last location message). | |
565 | This runs the command @code{gud-refresh}. | |
566 | ||
567 | @item C-c C-s | |
568 | @kindex C-c C-s @r{(GUD)} | |
569 | @itemx C-x C-a C-s | |
570 | @findex gud-step | |
571 | Execute a single line of code (@code{gud-step}). If the line contains | |
572 | a function call, execution stops after entering the called function. | |
573 | ||
574 | @item C-c C-n | |
575 | @kindex C-c C-n @r{(GUD)} | |
576 | @itemx C-x C-a C-n | |
577 | @findex gud-next | |
578 | Execute a single line of code, stepping across entire function calls | |
579 | at full speed (@code{gud-next}). | |
580 | ||
581 | @item C-c C-i | |
582 | @kindex C-c C-i @r{(GUD)} | |
583 | @itemx C-x C-a C-i | |
584 | @findex gud-stepi | |
585 | Execute a single machine instruction (@code{gud-stepi}). | |
586 | ||
587 | @need 3000 | |
588 | @item C-c C-r | |
589 | @kindex C-c C-r @r{(GUD)} | |
590 | @itemx C-x C-a C-r | |
591 | @findex gud-cont | |
592 | Continue execution without specifying any stopping point. The program | |
593 | will run until it hits a breakpoint, terminates, or gets a signal that | |
594 | the debugger is checking for (@code{gud-cont}). | |
595 | ||
596 | @need 1000 | |
597 | @item C-c C-d | |
598 | @kindex C-c C-d @r{(GUD)} | |
599 | @itemx C-x C-a C-d | |
600 | @findex gud-remove | |
601 | Delete the breakpoint(s) on the current source line, if any | |
602 | (@code{gud-remove}). If you use this command in the GUD interaction | |
603 | buffer, it applies to the line where the program last stopped. | |
604 | ||
605 | @item C-c C-t | |
606 | @kindex C-c C-t @r{(GUD)} | |
607 | @itemx C-x C-a C-t | |
608 | @findex gud-tbreak | |
609 | Set a temporary breakpoint on the current source line, if any. | |
610 | If you use this command in the GUD interaction buffer, | |
611 | it applies to the line where the program last stopped. | |
612 | @end table | |
613 | ||
614 | The above commands are common to all supported debuggers. If you are | |
615 | using GDB or (some versions of) DBX, these additional commands are available: | |
616 | ||
617 | @table @kbd | |
618 | @item C-c < | |
619 | @kindex C-c < @r{(GUD)} | |
620 | @itemx C-x C-a < | |
621 | @findex gud-up | |
622 | Select the next enclosing stack frame (@code{gud-up}). This is | |
623 | equivalent to the @samp{up} command. | |
624 | ||
625 | @item C-c > | |
626 | @kindex C-c > @r{(GUD)} | |
627 | @itemx C-x C-a > | |
628 | @findex gud-down | |
629 | Select the next inner stack frame (@code{gud-down}). This is | |
630 | equivalent to the @samp{down} command. | |
631 | @end table | |
632 | ||
633 | If you are using GDB, these additional key bindings are available: | |
634 | ||
635 | @table @kbd | |
f9ad161b RS |
636 | @item C-c C-r |
637 | @kindex C-c C-r @r{(GUD)} | |
638 | @itemx C-x C-a C-r | |
639 | @findex gud-run | |
640 | Start execution of the program (@code{gud-run}). | |
641 | ||
642 | @item C-c C-u | |
643 | @kindex C-c C-u @r{(GUD)} | |
644 | @itemx C-x C-a C-u | |
645 | @findex gud-until | |
646 | Continue execution to the current line. The program will run until | |
647 | it hits a breakpoint, terminates, gets a signal that the debugger is | |
648 | checking for, or reaches the line on which the cursor currently sits | |
649 | (@code{gud-until}). | |
650 | ||
6bf7aab6 DL |
651 | @item @key{TAB} |
652 | @kindex TAB @r{(GUD)} | |
653 | @findex gud-gdb-complete-command | |
654 | With GDB, complete a symbol name (@code{gud-gdb-complete-command}). | |
655 | This key is available only in the GUD interaction buffer, and requires | |
656 | GDB versions 4.13 and later. | |
657 | ||
658 | @item C-c C-f | |
659 | @kindex C-c C-f @r{(GUD)} | |
660 | @itemx C-x C-a C-f | |
661 | @findex gud-finish | |
662 | Run the program until the selected stack frame returns (or until it | |
663 | stops for some other reason). | |
5b7fc395 | 664 | |
44fa0ae8 RS |
665 | @item C-x C-a C-j |
666 | @kindex C-x C-a C-j @r{(GUD)} | |
5b7fc395 | 667 | @findex gud-jump |
44fa0ae8 RS |
668 | Only useful in a source buffer, (@code{gud-jump}) transfers the |
669 | program's execution point to the current line. In other words, the | |
670 | next line that the program executes will be the one where you gave the | |
671 | command. If the new execution line is in a different function from | |
672 | the previously one, GDB prompts for confirmation since the results may | |
673 | be bizarre. See the GDB manual entry regarding @code{jump} for | |
674 | details. | |
6bf7aab6 DL |
675 | @end table |
676 | ||
677 | These commands interpret a numeric argument as a repeat count, when | |
678 | that makes sense. | |
679 | ||
680 | Because @key{TAB} serves as a completion command, you can't use it to | |
681 | enter a tab as input to the program you are debugging with GDB. | |
682 | Instead, type @kbd{C-q @key{TAB}} to enter a tab. | |
683 | ||
684 | @node GUD Customization | |
685 | @subsection GUD Customization | |
686 | ||
687 | @vindex gdb-mode-hook | |
688 | @vindex dbx-mode-hook | |
689 | @vindex sdb-mode-hook | |
690 | @vindex xdb-mode-hook | |
691 | @vindex perldb-mode-hook | |
692 | @vindex pdb-mode-hook | |
693 | @vindex jdb-mode-hook | |
694 | On startup, GUD runs one of the following hooks: @code{gdb-mode-hook}, | |
695 | if you are using GDB; @code{dbx-mode-hook}, if you are using DBX; | |
696 | @code{sdb-mode-hook}, if you are using SDB; @code{xdb-mode-hook}, if you | |
697 | are using XDB; @code{perldb-mode-hook}, for Perl debugging mode; | |
74b1aac1 | 698 | @code{pdb-mode-hook}, for PDB; @code{jdb-mode-hook}, for JDB. You can |
6bf7aab6 DL |
699 | use these hooks to define custom key bindings for the debugger |
700 | interaction buffer. @xref{Hooks}. | |
701 | ||
702 | Here is a convenient way to define a command that sends a particular | |
703 | command string to the debugger, and set up a key binding for it in the | |
704 | debugger interaction buffer: | |
705 | ||
706 | @findex gud-def | |
707 | @example | |
708 | (gud-def @var{function} @var{cmdstring} @var{binding} @var{docstring}) | |
709 | @end example | |
710 | ||
711 | This defines a command named @var{function} which sends | |
712 | @var{cmdstring} to the debugger process, and gives it the documentation | |
7fb4961c | 713 | string @var{docstring}. You can then use the command @var{function} in any |
6bf7aab6 DL |
714 | buffer. If @var{binding} is non-@code{nil}, @code{gud-def} also binds |
715 | the command to @kbd{C-c @var{binding}} in the GUD buffer's mode and to | |
716 | @kbd{C-x C-a @var{binding}} generally. | |
717 | ||
718 | The command string @var{cmdstring} may contain certain | |
719 | @samp{%}-sequences that stand for data to be filled in at the time | |
720 | @var{function} is called: | |
721 | ||
722 | @table @samp | |
723 | @item %f | |
724 | The name of the current source file. If the current buffer is the GUD | |
725 | buffer, then the ``current source file'' is the file that the program | |
726 | stopped in. | |
727 | @c This said, ``the name of the file the program counter was in at the last breakpoint.'' | |
728 | @c But I suspect it is really the last stop file. | |
729 | ||
730 | @item %l | |
731 | The number of the current source line. If the current buffer is the GUD | |
732 | buffer, then the ``current source line'' is the line that the program | |
733 | stopped in. | |
734 | ||
735 | @item %e | |
736 | The text of the C lvalue or function-call expression at or adjacent to point. | |
737 | ||
738 | @item %a | |
739 | The text of the hexadecimal address at or adjacent to point. | |
740 | ||
741 | @item %p | |
742 | The numeric argument of the called function, as a decimal number. If | |
743 | the command is used without a numeric argument, @samp{%p} stands for the | |
744 | empty string. | |
745 | ||
746 | If you don't use @samp{%p} in the command string, the command you define | |
747 | ignores any numeric argument. | |
748 | @end table | |
749 | ||
f9ad161b RS |
750 | @node GDB Graphical Interface |
751 | @subsection GDB Graphical Interface | |
752 | ||
e4481965 NR |
753 | @findex gdb-mouse-set-clear-breakpoint |
754 | @findex gdb-mouse-toggle-breakpoint | |
499de9ba | 755 | By default, the command @code{gdb} starts GDB using a graphical |
31b4c1b7 NR |
756 | interface where you view and control the program's data using Emacs |
757 | windows. You can still interact with GDB through the GUD buffer, but | |
758 | the point of this mode is that you can do it through menus and clicks, | |
6bc7646b NR |
759 | without needing to know GDB commands. For example, you can click |
760 | @kbd{Mouse-1} in the fringe or display margin of a source buffer to | |
761 | set a breakpoint there and, on a graphical display, a red bullet will | |
762 | appear. If a breakpoint already exists on that line, this action will | |
4cf71604 NR |
763 | remove it. You can also enable or disable a breakpoint by clicking |
764 | @kbd{Mouse-3} on the bullet. If you drag the debugger arrow in the | |
765 | fringe with @kbd{Mouse-1}, execution will continue to the line where | |
766 | you release the button, provided it is still in the same frame | |
6bc7646b NR |
767 | (@code{gdb-mouse-until}). Alternatively, you can click @kbd{Mouse-2} |
768 | at some point in the fringe of this buffer and execution will advance | |
769 | to there. | |
31b4c1b7 | 770 | |
51344076 NR |
771 | This mode requires that GDB think that the screen size is unlimited, |
772 | and sets the height and width accordingly. For correct operation it | |
773 | is important that you don't change these values during the session. | |
774 | ||
499de9ba | 775 | @vindex gud-gdb-command-name |
f9ad161b | 776 | @findex gdba |
499de9ba RS |
777 | You can also run GDB in text command mode, which creates a buffer |
778 | for input and output to GDB. To do this, set | |
779 | @code{gud-gdb-command-name} to @code{"gdb --fullname"} or edit the | |
780 | startup command in the minibuffer to say that. You need to do use | |
781 | text command mode to run multiple debugging sessions within one Emacs | |
3d80e1a2 | 782 | session. If you have customized @code{gud-gdb-command-name} in that |
499de9ba | 783 | way, then you can use @kbd{M-x gdba} to invoke GDB in graphical mode. |
f9ad161b RS |
784 | |
785 | @menu | |
3e2546d7 NR |
786 | * GDB User Interface Layout:: Control the number of displayed buffers. |
787 | * Breakpoints Buffer:: A breakpoint control panel. | |
788 | * Stack Buffer:: Select a frame from the call stack. | |
789 | * Watch Expressions:: Monitor variable values in the speedbar. | |
f72b052c LT |
790 | * Other GDB User Interface Buffers:: Input/output, locals, registers, |
791 | assembler, threads and memory buffers. | |
f9ad161b RS |
792 | @end menu |
793 | ||
3e2546d7 NR |
794 | @node GDB User Interface Layout |
795 | @subsubsection GDB User Interface Layout | |
96110242 NR |
796 | @cindex GDB User Interface layout |
797 | ||
798 | @findex gdb-many-windows | |
799 | @vindex gdb-many-windows | |
800 | ||
801 | If the variable @code{gdb-many-windows} is @code{nil} (the default | |
802 | value) then gdb just pops up the GUD buffer unless the variable | |
803 | @code{gdb-show-main} is non-@code{nil}. In this case it starts with | |
804 | two windows: one displaying the GUD buffer and the other with the | |
805 | source file with the main routine of the inferior. | |
806 | ||
807 | If @code{gdb-many-windows} is non-@code{nil}, regardless of the value of | |
808 | @code{gdb-show-main}, the layout below will appear unless | |
809 | @code{gdb-use-inferior-io-buffer} is @code{nil}. In this case the | |
810 | source buffer occupies the full width of the frame. | |
811 | ||
1a0b66fe NR |
812 | @example |
813 | +--------------------------------+--------------------------------+ | |
814 | | | | | |
815 | | GUD buffer (I/O of GDB) | Locals buffer | | |
816 | | | | | |
817 | |--------------------------------+--------------------------------+ | |
818 | | | | | |
819 | | Source buffer | I/O buffer (of inferior) | | |
820 | | | | | |
821 | |--------------------------------+--------------------------------+ | |
822 | | | | | |
823 | | Stack buffer | Breakpoints buffer | | |
824 | | | | | |
825 | +--------------------------------+--------------------------------+ | |
826 | @end example | |
96110242 NR |
827 | |
828 | To toggle this layout, do @kbd{M-x gdb-many-windows}. | |
829 | ||
830 | @findex gdb-restore-windows | |
831 | If you change the window layout, for example, while editing and | |
832 | re-compiling your program, then you can restore it with the command | |
833 | @code{gdb-restore-windows}. | |
834 | ||
835 | You may also choose which additional buffers you want to display, | |
1a0b66fe NR |
836 | either in the same frame or a different one. Select them from |
837 | @samp{GUD->GDB-windows} or @samp{GUD->GDB-Frames} sub-menu | |
838 | respectively. If the menu-bar is unavailable, type @code{M-x | |
96110242 | 839 | gdb-display-@var{buffertype}-buffer} or @code{M-x |
1a0b66fe NR |
840 | gdb-frame-@var{buffertype}-buffer} respectively, where |
841 | @var{buffertype} is the relevant buffer type e.g breakpoints. | |
c3287027 NR |
842 | Most of these buffers are read-only and be killed by simply |
843 | pressing @kbd{q} in them. | |
96110242 | 844 | |
31b4c1b7 NR |
845 | When you finish debugging then kill the GUD buffer with @kbd{C-x k}, |
846 | which will also kill all the buffers associated with the session. | |
847 | However you need not do this if, after editing and re-compiling your | |
848 | source code within Emacs, you wish continue debugging. When you | |
849 | restart execution, GDB will automatically find your new executable. | |
850 | Keeping the GUD buffer has the advantage of keeping the shell history | |
851 | as well as GDB's breakpoints. You need to check, however, that the | |
852 | breakpoints in the recently edited code are still where you want them. | |
853 | ||
f9ad161b RS |
854 | @node Breakpoints Buffer |
855 | @subsubsection Breakpoints Buffer | |
856 | ||
254196f5 | 857 | The breakpoints buffer shows the existing breakpoints and watchpoints |
f9ad161b RS |
858 | (@pxref{Breakpoints,,, gdb, The GNU debugger}). It has three special |
859 | commands: | |
860 | ||
861 | @table @kbd | |
254196f5 | 862 | @item @key{SPC} |
f9ad161b RS |
863 | @kindex SPC @r{(GDB breakpoints buffer)} |
864 | @findex gdb-toggle-breakpoint | |
865 | Enable/disable the breakpoint at the current line | |
866 | (@code{gdb-toggle-breakpoint}). On a graphical display, this changes | |
867 | the color of a bullet in the margin of the source buffer at the | |
868 | relevant line. This is red when the breakpoint is enabled and grey | |
869 | when it is disabled. Text-only terminals correspondingly display | |
870 | a @samp{B} or @samp{b}. | |
871 | ||
c3287027 NR |
872 | @item D |
873 | @kindex D @r{(GDB breakpoints buffer)} | |
f9ad161b RS |
874 | @findex gdb-delete-breakpoint |
875 | Delete the breakpoint at the current line (@code{gdb-delete-breakpoint}). | |
876 | ||
877 | @item @key{RET} | |
878 | @kindex RET @r{(GDB breakpoints buffer)} | |
879 | @findex gdb-goto-breakpoint | |
880 | Display the file in the source buffer at the breakpoint specified at | |
90563cb3 NR |
881 | the current line (@code{gdb-goto-breakpoint}). Alternatively, click |
882 | @kbd{Mouse-2} on the breakpoint that you wish to visit. | |
f9ad161b RS |
883 | @end table |
884 | ||
885 | @node Stack Buffer | |
886 | @subsubsection Stack Buffer | |
887 | ||
888 | The stack buffer displays a @dfn{call stack}, with one line for each | |
889 | of the nested subroutine calls (@dfn{stack frames}) now active in the | |
1a0b66fe | 890 | program. @xref{Backtrace,, Backtraces, gdb, The GNU debugger}. |
f9ad161b | 891 | |
e4481965 NR |
892 | @findex gdb-frames-select |
893 | The selected frame number is displayed in reverse contrast. Move | |
894 | point to any frame in the stack and type @key{RET} to select it | |
895 | (@code{gdb-frames-select}) and display the associated source in the | |
896 | source buffer. Alternatively, click @kbd{Mouse-2} on a frame to | |
897 | select it. If the locals buffer is displayed then its contents update | |
898 | to display the variables that are local to the new frame. | |
f9ad161b | 899 | |
9b418429 NR |
900 | @node Watch Expressions |
901 | @subsubsection Watch Expressions | |
902 | @cindex Watching expressions in GDB | |
f9ad161b | 903 | |
e4481965 | 904 | @findex gud-watch |
f9ad161b | 905 | If you want to see how a variable changes each time your program stops |
9b418429 | 906 | then place the cursor over the variable name and click on the watch |
cb7b02c7 | 907 | icon in the tool bar (@code{gud-watch}). |
f9ad161b | 908 | |
8d66c08b NR |
909 | Each watch expression is displayed in the speedbar. Complex data |
910 | types, such as arrays, structures and unions are represented in a tree | |
f86711a4 | 911 | format. Leaves and simple data types show the name of the expression |
c3287027 NR |
912 | and its value, and display the type as a tooltip. Higher levels show |
913 | the name, type and address value for pointers and just the name and | |
914 | type otherwise. | |
bb8c3b15 NR |
915 | |
916 | To expand or contract a complex data type, click @kbd{Mouse-2} | |
8d66c08b | 917 | on the tag to the left of the expression. |
f9ad161b | 918 | |
9b418429 | 919 | @findex gdb-var-delete |
8d66c08b | 920 | With the cursor over the root expression of a complex data type, type |
96110242 | 921 | @kbd{D} to delete it from the speedbar |
8d66c08b NR |
922 | (@code{gdb-var-delete}). |
923 | ||
e4481965 | 924 | @kindex RET @r{(GDB speedbar)} |
8d66c08b NR |
925 | @findex gdb-edit-value |
926 | With the cursor over a simple data type or an element of a complex | |
927 | data type which holds a value, type @key{RET} or click @kbd{Mouse-2} to edit | |
928 | its value. A prompt for a new value appears in the mini-buffer | |
929 | (@code{gdb-edit-value}). | |
930 | ||
e4481965 | 931 | @vindex gdb-show-changed-values |
a1a3a37a | 932 | If you set the variable @code{gdb-show-changed-values} to |
e4481965 | 933 | non-@code{nil} (the default value), Emacs will use |
a1a3a37a NR |
934 | font-lock-warning-face to display values that have recently changed in |
935 | the speedbar. | |
8d66c08b | 936 | |
e4481965 | 937 | @vindex gdb-use-colon-colon-notation |
8d66c08b | 938 | If you set the variable @code{gdb-use-colon-colon-notation} to a |
e4481965 NR |
939 | non-@code{nil} value then, in C, Emacs will use the |
940 | @var{function}::@var{variable} format to display variables in the | |
941 | speedbar. Since this does not work for variables defined in compound | |
942 | statements, the default value is @code{nil}. | |
f9ad161b | 943 | |
3e2546d7 | 944 | @node Other GDB User Interface Buffers |
f9ad161b RS |
945 | @subsubsection Other Buffers |
946 | ||
947 | @table @asis | |
948 | @item Input/Output Buffer | |
e4481965 | 949 | @vindex gdb-use-inferior-io-buffer |
96110242 NR |
950 | If the variable @code{gdb-use-inferior-io-buffer} is non-@code{nil}, |
951 | the executable program that is being debugged takes its input and | |
d08a1c88 NR |
952 | displays its output here, otherwise it uses the GUD buffer. To toggle |
953 | the use of this buffer, do @kbd{M-x gdb-use-inferior-io-buffer}. | |
954 | ||
955 | Some of the commands from shell mode are available here. @xref{Shell | |
956 | Mode}. | |
f9ad161b RS |
957 | |
958 | @item Locals Buffer | |
959 | The locals buffer displays the values of local variables of the | |
1a0b66fe NR |
960 | current frame for simple data types (@pxref{Frame Info, Frame Info, |
961 | Information on a frame, gdb, The GNU debugger}). | |
f9ad161b | 962 | |
51344076 NR |
963 | Arrays and structures display their type only. With GDB 6.4 or later, |
964 | move point to their name and press @key{RET}, or alternatively click | |
965 | @kbd{Mouse-2} there, to examine their values. With earlier versions | |
966 | of GDB, move point to their type description ([struct/union] or | |
967 | [array]). @xref{Watch Expressions}. | |
f9ad161b RS |
968 | |
969 | @item Registers Buffer | |
e4481965 | 970 | @findex toggle-gdb-all-registers |
f9ad161b | 971 | The registers buffer displays the values held by the registers |
c3287027 NR |
972 | (@pxref{Registers,,, gdb, The GNU debugger}). Press @key{RET} or |
973 | click @kbd{Mouse-2} on a register if you want to change its value. | |
51344076 NR |
974 | With GDB 6.4 or later, recently changed register values display with |
975 | font-lock-warning-face. With earlier versions of GDB, you can press | |
976 | @key{SPC} to toggle the display of floating point registers | |
e4481965 | 977 | (@code{toggle-gdb-all-registers}). |
f9ad161b RS |
978 | |
979 | @item Assembler Buffer | |
980 | The assembler buffer displays the current frame as machine code. An | |
981 | overlay arrow points to the current instruction and you can set and | |
31b4c1b7 NR |
982 | remove breakpoints as with the source buffer. Breakpoint icons also |
983 | appear in the fringe or margin. | |
8d66c08b NR |
984 | |
985 | @item Threads Buffer | |
e4481965 | 986 | @findex gdb-threads-select |
8d66c08b | 987 | The threads buffer displays a summary of all threads currently in your |
1a0b66fe NR |
988 | program (@pxref{Threads, Threads, Debugging programs with multiple |
989 | threads, gdb, The GNU debugger}). Move point to any thread in the | |
990 | list and press @key{RET} to select it (@code{gdb-threads-select}) and | |
991 | display the associated source in the source buffer. Alternatively, | |
992 | click @kbd{Mouse-2} on a thread to select it. If the locals buffer is | |
993 | displayed then its contents update to display the variables that are | |
994 | local to the new thread. | |
8d66c08b | 995 | |
31b4c1b7 | 996 | @item Memory Buffer |
31b4c1b7 | 997 | The memory buffer allows the user to examine sections of program |
1a0b66fe NR |
998 | memory (@pxref{Memory, Memory, Examining memory, gdb, The GNU |
999 | debugger}). Click @kbd{Mouse-1} on the appropriate part of the header | |
1000 | line to change the starting address or number of data items that the | |
1001 | buffer displays. Click @kbd{Mouse-3} on the header line to select the | |
1002 | display format or unit size for these data items. | |
31b4c1b7 | 1003 | |
f9ad161b RS |
1004 | @end table |
1005 | ||
6bf7aab6 DL |
1006 | @node Executing Lisp |
1007 | @section Executing Lisp Expressions | |
1008 | ||
1009 | Emacs has several different major modes for Lisp and Scheme. They are | |
1010 | the same in terms of editing commands, but differ in the commands for | |
1011 | executing Lisp expressions. Each mode has its own purpose. | |
1012 | ||
1013 | @table @asis | |
1014 | @item Emacs-Lisp mode | |
1015 | The mode for editing source files of programs to run in Emacs Lisp. | |
1016 | This mode defines @kbd{C-M-x} to evaluate the current defun. | |
1017 | @xref{Lisp Libraries}. | |
1018 | @item Lisp Interaction mode | |
1019 | The mode for an interactive session with Emacs Lisp. It defines | |
1020 | @kbd{C-j} to evaluate the sexp before point and insert its value in the | |
1021 | buffer. @xref{Lisp Interaction}. | |
1022 | @item Lisp mode | |
1023 | The mode for editing source files of programs that run in Lisps other | |
1024 | than Emacs Lisp. This mode defines @kbd{C-M-x} to send the current defun | |
1025 | to an inferior Lisp process. @xref{External Lisp}. | |
1026 | @item Inferior Lisp mode | |
1027 | The mode for an interactive session with an inferior Lisp process. | |
1028 | This mode combines the special features of Lisp mode and Shell mode | |
1029 | (@pxref{Shell Mode}). | |
1030 | @item Scheme mode | |
1031 | Like Lisp mode but for Scheme programs. | |
1032 | @item Inferior Scheme mode | |
1033 | The mode for an interactive session with an inferior Scheme process. | |
1034 | @end table | |
1035 | ||
1036 | Most editing commands for working with Lisp programs are in fact | |
1037 | available globally. @xref{Programs}. | |
1038 | ||
1039 | @node Lisp Libraries | |
1040 | @section Libraries of Lisp Code for Emacs | |
1041 | @cindex libraries | |
1042 | @cindex loading Lisp code | |
1043 | ||
1044 | Lisp code for Emacs editing commands is stored in files whose names | |
1045 | conventionally end in @file{.el}. This ending tells Emacs to edit them in | |
1046 | Emacs-Lisp mode (@pxref{Executing Lisp}). | |
1047 | ||
1048 | @findex load-file | |
1049 | To execute a file of Emacs Lisp code, use @kbd{M-x load-file}. This | |
1050 | command reads a file name using the minibuffer and then executes the | |
1051 | contents of that file as Lisp code. It is not necessary to visit the | |
1052 | file first; in any case, this command reads the file as found on disk, | |
1053 | not text in an Emacs buffer. | |
1054 | ||
1055 | @findex load | |
1056 | @findex load-library | |
1057 | Once a file of Lisp code is installed in the Emacs Lisp library | |
1058 | directories, users can load it using @kbd{M-x load-library}. Programs can | |
1059 | load it by calling @code{load-library}, or with @code{load}, a more primitive | |
1060 | function that is similar but accepts some additional arguments. | |
1061 | ||
1062 | @kbd{M-x load-library} differs from @kbd{M-x load-file} in that it | |
1063 | searches a sequence of directories and tries three file names in each | |
1064 | directory. Suppose your argument is @var{lib}; the three names are | |
1065 | @file{@var{lib}.elc}, @file{@var{lib}.el}, and lastly just | |
1066 | @file{@var{lib}}. If @file{@var{lib}.elc} exists, it is by convention | |
1067 | the result of compiling @file{@var{lib}.el}; it is better to load the | |
1068 | compiled file, since it will load and run faster. | |
1069 | ||
1070 | If @code{load-library} finds that @file{@var{lib}.el} is newer than | |
48dbca2c | 1071 | @file{@var{lib}.elc} file, it issues a warning, because it's likely that |
6bf7aab6 DL |
1072 | somebody made changes to the @file{.el} file and forgot to recompile |
1073 | it. | |
1074 | ||
1075 | Because the argument to @code{load-library} is usually not in itself | |
1076 | a valid file name, file name completion is not available. Indeed, when | |
1077 | using this command, you usually do not know exactly what file name | |
1078 | will be used. | |
1079 | ||
1080 | @vindex load-path | |
1081 | The sequence of directories searched by @kbd{M-x load-library} is | |
1082 | specified by the variable @code{load-path}, a list of strings that are | |
1083 | directory names. The default value of the list contains the directory where | |
1084 | the Lisp code for Emacs itself is stored. If you have libraries of | |
1085 | your own, put them in a single directory and add that directory | |
1086 | to @code{load-path}. @code{nil} in this list stands for the current default | |
1087 | directory, but it is probably not a good idea to put @code{nil} in the | |
1088 | list. If you find yourself wishing that @code{nil} were in the list, | |
1089 | most likely what you really want to do is use @kbd{M-x load-file} | |
1090 | this once. | |
1091 | ||
1092 | @cindex autoload | |
1093 | Often you do not have to give any command to load a library, because | |
1094 | the commands defined in the library are set up to @dfn{autoload} that | |
1095 | library. Trying to run any of those commands calls @code{load} to load | |
1096 | the library; this replaces the autoload definitions with the real ones | |
1097 | from the library. | |
1098 | ||
1099 | @cindex byte code | |
1100 | Emacs Lisp code can be compiled into byte-code which loads faster, | |
1101 | takes up less space when loaded, and executes faster. @xref{Byte | |
1102 | Compilation,, Byte Compilation, elisp, the Emacs Lisp Reference Manual}. | |
1103 | By convention, the compiled code for a library goes in a separate file | |
1104 | whose name consists of the library source file with @samp{c} appended. | |
1105 | Thus, the compiled code for @file{foo.el} goes in @file{foo.elc}. | |
1106 | That's why @code{load-library} searches for @samp{.elc} files first. | |
1107 | ||
493c59e0 EZ |
1108 | @vindex load-dangerous-libraries |
1109 | @cindex Lisp files byte-compiled by XEmacs | |
a50c7a80 RS |
1110 | By default, Emacs refuses to load compiled Lisp files which were |
1111 | compiled with XEmacs, a modified versions of Emacs---they can cause | |
1112 | Emacs to crash. Set the variable @code{load-dangerous-libraries} to | |
1113 | @code{t} if you want to try loading them. | |
493c59e0 | 1114 | |
6bf7aab6 | 1115 | @node Lisp Eval |
dd525369 | 1116 | @section Evaluating Emacs Lisp Expressions |
6bf7aab6 DL |
1117 | @cindex Emacs-Lisp mode |
1118 | @cindex mode, Emacs-Lisp | |
1119 | ||
1120 | @findex emacs-lisp-mode | |
1121 | Lisp programs intended to be run in Emacs should be edited in | |
1122 | Emacs-Lisp mode; this happens automatically for file names ending in | |
1123 | @file{.el}. By contrast, Lisp mode itself is used for editing Lisp | |
1124 | programs intended for other Lisp systems. To switch to Emacs-Lisp mode | |
1125 | explicitly, use the command @kbd{M-x emacs-lisp-mode}. | |
1126 | ||
1127 | For testing of Lisp programs to run in Emacs, it is often useful to | |
1128 | evaluate part of the program as it is found in the Emacs buffer. For | |
1129 | example, after changing the text of a Lisp function definition, | |
1130 | evaluating the definition installs the change for future calls to the | |
1131 | function. Evaluation of Lisp expressions is also useful in any kind of | |
1132 | editing, for invoking noninteractive functions (functions that are | |
1133 | not commands). | |
1134 | ||
1135 | @table @kbd | |
1136 | @item M-: | |
1137 | Read a single Lisp expression in the minibuffer, evaluate it, and print | |
1138 | the value in the echo area (@code{eval-expression}). | |
1139 | @item C-x C-e | |
1140 | Evaluate the Lisp expression before point, and print the value in the | |
1141 | echo area (@code{eval-last-sexp}). | |
1142 | @item C-M-x | |
1143 | Evaluate the defun containing or after point, and print the value in | |
1144 | the echo area (@code{eval-defun}). | |
1145 | @item M-x eval-region | |
1146 | Evaluate all the Lisp expressions in the region. | |
1147 | @item M-x eval-current-buffer | |
1148 | Evaluate all the Lisp expressions in the buffer. | |
1149 | @end table | |
1150 | ||
09041c4b | 1151 | @ifinfo |
c668cdd0 EZ |
1152 | @c This uses ``colon'' instead of a literal `:' because Info cannot |
1153 | @c cope with a `:' in a menu | |
1154 | @kindex M-@key{colon} | |
09041c4b EZ |
1155 | @end ifinfo |
1156 | @ifnotinfo | |
1157 | @kindex M-: | |
1158 | @end ifnotinfo | |
6bf7aab6 DL |
1159 | @findex eval-expression |
1160 | @kbd{M-:} (@code{eval-expression}) is the most basic command for evaluating | |
1161 | a Lisp expression interactively. It reads the expression using the | |
1162 | minibuffer, so you can execute any expression on a buffer regardless of | |
1163 | what the buffer contains. When the expression is evaluated, the current | |
1164 | buffer is once again the buffer that was current when @kbd{M-:} was | |
1165 | typed. | |
1166 | ||
1167 | @kindex C-M-x @r{(Emacs-Lisp mode)} | |
1168 | @findex eval-defun | |
1169 | In Emacs-Lisp mode, the key @kbd{C-M-x} is bound to the command | |
1170 | @code{eval-defun}, which parses the defun containing or following point | |
1171 | as a Lisp expression and evaluates it. The value is printed in the echo | |
1172 | area. This command is convenient for installing in the Lisp environment | |
1173 | changes that you have just made in the text of a function definition. | |
1174 | ||
1175 | @kbd{C-M-x} treats @code{defvar} expressions specially. Normally, | |
1176 | evaluating a @code{defvar} expression does nothing if the variable it | |
1177 | defines already has a value. But @kbd{C-M-x} unconditionally resets the | |
1178 | variable to the initial value specified in the @code{defvar} expression. | |
9c8599ca | 1179 | @code{defcustom} expressions are treated similarly. |
6bf7aab6 | 1180 | This special feature is convenient for debugging Lisp programs. |
dc134342 JL |
1181 | Typing @kbd{C-M-x} on a @code{defface} expression reinitializes |
1182 | the face according to the @code{defface} specification. | |
6bf7aab6 DL |
1183 | |
1184 | @kindex C-x C-e | |
1185 | @findex eval-last-sexp | |
1186 | The command @kbd{C-x C-e} (@code{eval-last-sexp}) evaluates the Lisp | |
1187 | expression preceding point in the buffer, and displays the value in the | |
1188 | echo area. It is available in all major modes, not just Emacs-Lisp | |
1189 | mode. It does not treat @code{defvar} specially. | |
1190 | ||
ed4389af RS |
1191 | When the result of an evaluation is an integer, you can type |
1192 | @kbd{C-x C-e} a second time to display the value of the integer result | |
1193 | in additional formats (octal, hexadecimal, and character). | |
1194 | ||
c91809b2 RS |
1195 | If @kbd{C-x C-e}, or @kbd{M-:} is given a numeric argument, it |
1196 | inserts the value into the current buffer at point, rather than | |
1197 | displaying it in the echo area. The argument's value does not matter. | |
1198 | @kbd{C-M-x} with a numeric argument instruments the function | |
1199 | definition for Edebug (@pxref{Instrumenting, Instrumenting for Edebug,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
1200 | |
1201 | @findex eval-region | |
1202 | @findex eval-current-buffer | |
1203 | The most general command for evaluating Lisp expressions from a buffer | |
1204 | is @code{eval-region}. @kbd{M-x eval-region} parses the text of the | |
1205 | region as one or more Lisp expressions, evaluating them one by one. | |
1206 | @kbd{M-x eval-current-buffer} is similar but evaluates the entire | |
1207 | buffer. This is a reasonable way to install the contents of a file of | |
58fa012d | 1208 | Lisp code that you are ready to test. Later, as you find bugs and |
6bf7aab6 DL |
1209 | change individual functions, use @kbd{C-M-x} on each function that you |
1210 | change. This keeps the Lisp world in step with the source file. | |
1211 | ||
9c8599ca DL |
1212 | @vindex eval-expression-print-level |
1213 | @vindex eval-expression-print-length | |
1214 | @vindex eval-expression-debug-on-error | |
1215 | The customizable variables @code{eval-expression-print-level} and | |
1216 | @code{eval-expression-print-length} control the maximum depth and length | |
1217 | of lists to print in the result of the evaluation commands before | |
1218 | abbreviating them. @code{eval-expression-debug-on-error} controls | |
1219 | whether evaluation errors invoke the debugger when these commands are | |
1220 | used. | |
1221 | ||
6bf7aab6 DL |
1222 | @node Lisp Interaction |
1223 | @section Lisp Interaction Buffers | |
1224 | ||
1225 | The buffer @samp{*scratch*} which is selected when Emacs starts up is | |
1226 | provided for evaluating Lisp expressions interactively inside Emacs. | |
1227 | ||
1228 | The simplest way to use the @samp{*scratch*} buffer is to insert Lisp | |
1229 | expressions and type @kbd{C-j} after each expression. This command | |
1230 | reads the Lisp expression before point, evaluates it, and inserts the | |
1231 | value in printed representation before point. The result is a complete | |
1232 | typescript of the expressions you have evaluated and their values. | |
1233 | ||
1234 | The @samp{*scratch*} buffer's major mode is Lisp Interaction mode, which | |
1235 | is the same as Emacs-Lisp mode except for the binding of @kbd{C-j}. | |
1236 | ||
1237 | @findex lisp-interaction-mode | |
1238 | The rationale for this feature is that Emacs must have a buffer when | |
1239 | it starts up, but that buffer is not useful for editing files since a | |
1240 | new buffer is made for every file that you visit. The Lisp interpreter | |
1241 | typescript is the most useful thing I can think of for the initial | |
1242 | buffer to do. Type @kbd{M-x lisp-interaction-mode} to put the current | |
1243 | buffer in Lisp Interaction mode. | |
1244 | ||
1245 | @findex ielm | |
1246 | An alternative way of evaluating Emacs Lisp expressions interactively | |
1247 | is to use Inferior Emacs-Lisp mode, which provides an interface rather | |
1248 | like Shell mode (@pxref{Shell Mode}) for evaluating Emacs Lisp | |
1249 | expressions. Type @kbd{M-x ielm} to create an @samp{*ielm*} buffer | |
1250 | which uses this mode. | |
1251 | ||
1252 | @node External Lisp | |
1253 | @section Running an External Lisp | |
1254 | ||
1255 | Emacs has facilities for running programs in other Lisp systems. You can | |
1256 | run a Lisp process as an inferior of Emacs, and pass expressions to it to | |
1257 | be evaluated. You can also pass changed function definitions directly from | |
1258 | the Emacs buffers in which you edit the Lisp programs to the inferior Lisp | |
1259 | process. | |
1260 | ||
1261 | @findex run-lisp | |
1262 | @vindex inferior-lisp-program | |
1263 | @kindex C-x C-z | |
1264 | To run an inferior Lisp process, type @kbd{M-x run-lisp}. This runs | |
1265 | the program named @code{lisp}, the same program you would run by typing | |
1266 | @code{lisp} as a shell command, with both input and output going through | |
1267 | an Emacs buffer named @samp{*lisp*}. That is to say, any ``terminal | |
1268 | output'' from Lisp will go into the buffer, advancing point, and any | |
1269 | ``terminal input'' for Lisp comes from text in the buffer. (You can | |
1270 | change the name of the Lisp executable file by setting the variable | |
1271 | @code{inferior-lisp-program}.) | |
1272 | ||
1273 | To give input to Lisp, go to the end of the buffer and type the input, | |
1274 | terminated by @key{RET}. The @samp{*lisp*} buffer is in Inferior Lisp | |
1275 | mode, which combines the special characteristics of Lisp mode with most | |
1276 | of the features of Shell mode (@pxref{Shell Mode}). The definition of | |
1277 | @key{RET} to send a line to a subprocess is one of the features of Shell | |
1278 | mode. | |
1279 | ||
1280 | @findex lisp-mode | |
1281 | For the source files of programs to run in external Lisps, use Lisp | |
1282 | mode. This mode can be selected with @kbd{M-x lisp-mode}, and is used | |
1283 | automatically for files whose names end in @file{.l}, @file{.lsp}, or | |
1284 | @file{.lisp}, as most Lisp systems usually expect. | |
1285 | ||
1286 | @kindex C-M-x @r{(Lisp mode)} | |
1287 | @findex lisp-eval-defun | |
1288 | When you edit a function in a Lisp program you are running, the easiest | |
1289 | way to send the changed definition to the inferior Lisp process is the key | |
1290 | @kbd{C-M-x}. In Lisp mode, this runs the function @code{lisp-eval-defun}, | |
1291 | which finds the defun around or following point and sends it as input to | |
1292 | the Lisp process. (Emacs can send input to any inferior process regardless | |
1293 | of what buffer is current.) | |
1294 | ||
1295 | Contrast the meanings of @kbd{C-M-x} in Lisp mode (for editing programs | |
1296 | to be run in another Lisp system) and Emacs-Lisp mode (for editing Lisp | |
1297 | programs to be run in Emacs): in both modes it has the effect of installing | |
1298 | the function definition that point is in, but the way of doing so is | |
1299 | different according to where the relevant Lisp environment is found. | |
1300 | @xref{Executing Lisp}. | |
ab5796a9 MB |
1301 | |
1302 | @ignore | |
1303 | arch-tag: 9c3c2f71-b332-4144-8500-3ff9945a50ed | |
1304 | @end ignore |