|
0
|
1 @c -*-texinfo-*-
|
|
|
2 @c This is part of the XEmacs Lisp Reference Manual.
|
|
|
3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
|
|
|
4 @c See the file lispref.texi for copying conditions.
|
|
|
5 @setfilename ../../info/processes.info
|
|
|
6 @node Processes, System Interface, Databases, Top
|
|
|
7 @chapter Processes
|
|
|
8 @cindex child process
|
|
|
9 @cindex parent process
|
|
|
10 @cindex subprocess
|
|
|
11 @cindex process
|
|
|
12
|
|
|
13 In the terminology of operating systems, a @dfn{process} is a space in
|
|
|
14 which a program can execute. XEmacs runs in a process. XEmacs Lisp
|
|
|
15 programs can invoke other programs in processes of their own. These are
|
|
|
16 called @dfn{subprocesses} or @dfn{child processes} of the XEmacs process,
|
|
|
17 which is their @dfn{parent process}.
|
|
|
18
|
|
|
19 A subprocess of XEmacs may be @dfn{synchronous} or @dfn{asynchronous},
|
|
|
20 depending on how it is created. When you create a synchronous
|
|
|
21 subprocess, the Lisp program waits for the subprocess to terminate
|
|
|
22 before continuing execution. When you create an asynchronous
|
|
|
23 subprocess, it can run in parallel with the Lisp program. This kind of
|
|
|
24 subprocess is represented within XEmacs by a Lisp object which is also
|
|
|
25 called a ``process''. Lisp programs can use this object to communicate
|
|
|
26 with the subprocess or to control it. For example, you can send
|
|
|
27 signals, obtain status information, receive output from the process, or
|
|
|
28 send input to it.
|
|
|
29
|
|
|
30 @defun processp object
|
|
|
31 This function returns @code{t} if @var{object} is a process,
|
|
|
32 @code{nil} otherwise.
|
|
|
33 @end defun
|
|
|
34
|
|
|
35 @menu
|
|
|
36 * Subprocess Creation:: Functions that start subprocesses.
|
|
|
37 * Synchronous Processes:: Details of using synchronous subprocesses.
|
|
|
38 * MS-DOS Subprocesses:: On MS-DOS, you must indicate text vs binary
|
|
|
39 for data sent to and from a subprocess.
|
|
|
40 * Asynchronous Processes:: Starting up an asynchronous subprocess.
|
|
|
41 * Deleting Processes:: Eliminating an asynchronous subprocess.
|
|
|
42 * Process Information:: Accessing run-status and other attributes.
|
|
|
43 * Input to Processes:: Sending input to an asynchronous subprocess.
|
|
|
44 * Signals to Processes:: Stopping, continuing or interrupting
|
|
|
45 an asynchronous subprocess.
|
|
|
46 * Output from Processes:: Collecting output from an asynchronous subprocess.
|
|
|
47 * Sentinels:: Sentinels run when process run-status changes.
|
|
|
48 * Process Window Size:: Changing the logical window size of a process.
|
|
|
49 * Transaction Queues:: Transaction-based communication with subprocesses.
|
|
|
50 * Network:: Opening network connections.
|
|
|
51 @end menu
|
|
|
52
|
|
|
53 @node Subprocess Creation
|
|
|
54 @section Functions that Create Subprocesses
|
|
|
55
|
|
|
56 There are three functions that create a new subprocess in which to run
|
|
|
57 a program. One of them, @code{start-process}, creates an asynchronous
|
|
|
58 process and returns a process object (@pxref{Asynchronous Processes}).
|
|
|
59 The other two, @code{call-process} and @code{call-process-region},
|
|
|
60 create a synchronous process and do not return a process object
|
|
|
61 (@pxref{Synchronous Processes}).
|
|
|
62
|
|
|
63 Synchronous and asynchronous processes are explained in following
|
|
|
64 sections. Since the three functions are all called in a similar
|
|
|
65 fashion, their common arguments are described here.
|
|
|
66
|
|
|
67 @cindex execute program
|
|
|
68 @cindex @code{PATH} environment variable
|
|
|
69 @cindex @code{HOME} environment variable
|
|
|
70 In all cases, the function's @var{program} argument specifies the
|
|
|
71 program to be run. An error is signaled if the file is not found or
|
|
|
72 cannot be executed. If the file name is relative, the variable
|
|
|
73 @code{exec-path} contains a list of directories to search. Emacs
|
|
|
74 initializes @code{exec-path} when it starts up, based on the value of
|
|
|
75 the environment variable @code{PATH}. The standard file name
|
|
|
76 constructs, @samp{~}, @samp{.}, and @samp{..}, are interpreted as usual
|
|
|
77 in @code{exec-path}, but environment variable substitutions
|
|
|
78 (@samp{$HOME}, etc.) are not recognized; use
|
|
|
79 @code{substitute-in-file-name} to perform them (@pxref{File Name
|
|
|
80 Expansion}).
|
|
|
81
|
|
|
82 Each of the subprocess-creating functions has a @var{buffer-or-name}
|
|
|
83 argument which specifies where the standard output from the program will
|
|
|
84 go. If @var{buffer-or-name} is @code{nil}, that says to discard the
|
|
|
85 output unless a filter function handles it. (@xref{Filter Functions},
|
|
|
86 and @ref{Read and Print}.) Normally, you should avoid having multiple
|
|
|
87 processes send output to the same buffer because their output would be
|
|
|
88 intermixed randomly.
|
|
|
89
|
|
|
90 @cindex program arguments
|
|
|
91 All three of the subprocess-creating functions have a @code{&rest}
|
|
|
92 argument, @var{args}. The @var{args} must all be strings, and they are
|
|
|
93 supplied to @var{program} as separate command line arguments. Wildcard
|
|
|
94 characters and other shell constructs are not allowed in these strings,
|
|
|
95 since they are passed directly to the specified program.
|
|
|
96
|
|
|
97 @strong{Please note:} The argument @var{program} contains only the
|
|
|
98 name of the program; it may not contain any command-line arguments. You
|
|
|
99 must use @var{args} to provide those.
|
|
|
100
|
|
|
101 The subprocess gets its current directory from the value of
|
|
|
102 @code{default-directory} (@pxref{File Name Expansion}).
|
|
|
103
|
|
|
104 @cindex environment variables, subprocesses
|
|
|
105 The subprocess inherits its environment from XEmacs; but you can
|
|
|
106 specify overrides for it with @code{process-environment}. @xref{System
|
|
|
107 Environment}.
|
|
|
108
|
|
|
109 @defvar exec-directory
|
|
|
110 @pindex wakeup
|
|
|
111 The value of this variable is the name of a directory (a string) that
|
|
|
112 contains programs that come with XEmacs, that are intended for XEmacs
|
|
|
113 to invoke. The program @code{wakeup} is an example of such a program;
|
|
|
114 the @code{display-time} command uses it to get a reminder once per
|
|
|
115 minute.
|
|
|
116 @end defvar
|
|
|
117
|
|
|
118 @defopt exec-path
|
|
|
119 The value of this variable is a list of directories to search for
|
|
|
120 programs to run in subprocesses. Each element is either the name of a
|
|
|
121 directory (i.e., a string), or @code{nil}, which stands for the default
|
|
|
122 directory (which is the value of @code{default-directory}).
|
|
|
123 @cindex program directories
|
|
|
124
|
|
|
125 The value of @code{exec-path} is used by @code{call-process} and
|
|
|
126 @code{start-process} when the @var{program} argument is not an absolute
|
|
|
127 file name.
|
|
|
128 @end defopt
|
|
|
129
|
|
|
130 @node Synchronous Processes
|
|
|
131 @section Creating a Synchronous Process
|
|
|
132 @cindex synchronous subprocess
|
|
|
133
|
|
|
134 After a @dfn{synchronous process} is created, XEmacs waits for the
|
|
|
135 process to terminate before continuing. Starting Dired is an example of
|
|
|
136 this: it runs @code{ls} in a synchronous process, then modifies the
|
|
|
137 output slightly. Because the process is synchronous, the entire
|
|
|
138 directory listing arrives in the buffer before XEmacs tries to do
|
|
|
139 anything with it.
|
|
|
140
|
|
|
141 While Emacs waits for the synchronous subprocess to terminate, the
|
|
|
142 user can quit by typing @kbd{C-g}. The first @kbd{C-g} tries to kill
|
|
|
143 the subprocess with a @code{SIGINT} signal; but it waits until the
|
|
|
144 subprocess actually terminates before quitting. If during that time the
|
|
|
145 user types another @kbd{C-g}, that kills the subprocess instantly with
|
|
|
146 @code{SIGKILL} and quits immediately. @xref{Quitting}.
|
|
|
147
|
|
|
148 The synchronous subprocess functions returned @code{nil} in version
|
|
|
149 18. In version 19, they return an indication of how the process
|
|
|
150 terminated.
|
|
|
151
|
|
|
152 @defun call-process program &optional infile destination display &rest args
|
|
|
153 This function calls @var{program} in a separate process and waits for
|
|
|
154 it to finish.
|
|
|
155
|
|
|
156 The standard input for the process comes from file @var{infile} if
|
|
|
157 @var{infile} is not @code{nil} and from @file{/dev/null} otherwise.
|
|
|
158 The argument @var{destination} says where to put the process output.
|
|
|
159 Here are the possibilities:
|
|
|
160
|
|
|
161 @table @asis
|
|
|
162 @item a buffer
|
|
|
163 Insert the output in that buffer, before point. This includes both the
|
|
|
164 standard output stream and the standard error stream of the process.
|
|
|
165
|
|
|
166 @item a string
|
|
|
167 Find or create a buffer with that name, then insert
|
|
|
168 the output in that buffer, before point.
|
|
|
169
|
|
|
170 @item @code{t}
|
|
|
171 Insert the output in the current buffer, before point.
|
|
|
172
|
|
|
173 @item @code{nil}
|
|
|
174 Discard the output.
|
|
|
175
|
|
|
176 @item 0
|
|
|
177 Discard the output, and return immediately without waiting
|
|
|
178 for the subprocess to finish.
|
|
|
179
|
|
|
180 In this case, the process is not truly synchronous, since it can run in
|
|
|
181 parallel with Emacs; but you can think of it as synchronous in that
|
|
|
182 Emacs is essentially finished with the subprocess as soon as this
|
|
|
183 function returns.
|
|
|
184
|
|
|
185 @item (@var{real-destination} @var{error-destination})
|
|
|
186 Keep the standard output stream separate from the standard error stream;
|
|
|
187 deal with the ordinary output as specified by @var{real-destination},
|
|
|
188 and dispose of the error output according to @var{error-destination}.
|
|
|
189 The value @code{nil} means discard it, @code{t} means mix it with the
|
|
|
190 ordinary output, and a string specifies a file name to redirect error
|
|
|
191 output into.
|
|
|
192
|
|
|
193 You can't directly specify a buffer to put the error output in; that is
|
|
|
194 too difficult to implement. But you can achieve this result by sending
|
|
|
195 the error output to a temporary file and then inserting the file into a
|
|
|
196 buffer.
|
|
|
197 @end table
|
|
|
198
|
|
|
199 If @var{display} is non-@code{nil}, then @code{call-process} redisplays
|
|
|
200 the buffer as output is inserted. Otherwise the function does no
|
|
|
201 redisplay, and the results become visible on the screen only when XEmacs
|
|
|
202 redisplays that buffer in the normal course of events.
|
|
|
203
|
|
|
204 The remaining arguments, @var{args}, are strings that specify command
|
|
|
205 line arguments for the program.
|
|
|
206
|
|
|
207 The value returned by @code{call-process} (unless you told it not to
|
|
|
208 wait) indicates the reason for process termination. A number gives the
|
|
|
209 exit status of the subprocess; 0 means success, and any other value
|
|
|
210 means failure. If the process terminated with a signal,
|
|
|
211 @code{call-process} returns a string describing the signal.
|
|
|
212
|
|
|
213 In the examples below, the buffer @samp{foo} is current.
|
|
|
214
|
|
|
215 @smallexample
|
|
|
216 @group
|
|
|
217 (call-process "pwd" nil t)
|
|
|
218 @result{} nil
|
|
|
219
|
|
|
220 ---------- Buffer: foo ----------
|
|
|
221 /usr/user/lewis/manual
|
|
|
222 ---------- Buffer: foo ----------
|
|
|
223 @end group
|
|
|
224
|
|
|
225 @group
|
|
|
226 (call-process "grep" nil "bar" nil "lewis" "/etc/passwd")
|
|
|
227 @result{} nil
|
|
|
228
|
|
|
229 ---------- Buffer: bar ----------
|
|
|
230 lewis:5LTsHm66CSWKg:398:21:Bil Lewis:/user/lewis:/bin/csh
|
|
|
231
|
|
|
232 ---------- Buffer: bar ----------
|
|
|
233 @end group
|
|
|
234 @end smallexample
|
|
|
235
|
|
|
236 The @code{insert-directory} function contains a good example of the use
|
|
|
237 of @code{call-process}:
|
|
|
238
|
|
|
239 @smallexample
|
|
|
240 @group
|
|
|
241 (call-process insert-directory-program nil t nil switches
|
|
|
242 (if full-directory-p
|
|
|
243 (concat (file-name-as-directory file) ".")
|
|
|
244 file))
|
|
|
245 @end group
|
|
|
246 @end smallexample
|
|
|
247 @end defun
|
|
|
248
|
|
|
249 @defun call-process-region start end program &optional delete destination display &rest args
|
|
|
250 This function sends the text between @var{start} to @var{end} as
|
|
|
251 standard input to a process running @var{program}. It deletes the text
|
|
|
252 sent if @var{delete} is non-@code{nil}; this is useful when @var{buffer}
|
|
|
253 is @code{t}, to insert the output in the current buffer.
|
|
|
254
|
|
|
255 The arguments @var{destination} and @var{display} control what to do
|
|
|
256 with the output from the subprocess, and whether to update the display
|
|
|
257 as it comes in. For details, see the description of
|
|
|
258 @code{call-process}, above. If @var{destination} is the integer 0,
|
|
|
259 @code{call-process-region} discards the output and returns @code{nil}
|
|
|
260 immediately, without waiting for the subprocess to finish.
|
|
|
261
|
|
|
262 The remaining arguments, @var{args}, are strings that specify command
|
|
|
263 line arguments for the program.
|
|
|
264
|
|
|
265 The return value of @code{call-process-region} is just like that of
|
|
|
266 @code{call-process}: @code{nil} if you told it to return without
|
|
|
267 waiting; otherwise, a number or string which indicates how the
|
|
|
268 subprocess terminated.
|
|
|
269
|
|
|
270 In the following example, we use @code{call-process-region} to run the
|
|
|
271 @code{cat} utility, with standard input being the first five characters
|
|
|
272 in buffer @samp{foo} (the word @samp{input}). @code{cat} copies its
|
|
|
273 standard input into its standard output. Since the argument
|
|
|
274 @var{destination} is @code{t}, this output is inserted in the current
|
|
|
275 buffer.
|
|
|
276
|
|
|
277 @smallexample
|
|
|
278 @group
|
|
|
279 ---------- Buffer: foo ----------
|
|
|
280 input@point{}
|
|
|
281 ---------- Buffer: foo ----------
|
|
|
282 @end group
|
|
|
283
|
|
|
284 @group
|
|
|
285 (call-process-region 1 6 "cat" nil t)
|
|
|
286 @result{} nil
|
|
|
287
|
|
|
288 ---------- Buffer: foo ----------
|
|
|
289 inputinput@point{}
|
|
|
290 ---------- Buffer: foo ----------
|
|
|
291 @end group
|
|
|
292 @end smallexample
|
|
|
293
|
|
|
294 The @code{shell-command-on-region} command uses
|
|
|
295 @code{call-process-region} like this:
|
|
|
296
|
|
|
297 @smallexample
|
|
|
298 @group
|
|
|
299 (call-process-region
|
|
|
300 start end
|
|
|
301 shell-file-name ; @r{Name of program.}
|
|
|
302 nil ; @r{Do not delete region.}
|
|
|
303 buffer ; @r{Send output to @code{buffer}.}
|
|
|
304 nil ; @r{No redisplay during output.}
|
|
|
305 "-c" command) ; @r{Arguments for the shell.}
|
|
|
306 @end group
|
|
|
307 @end smallexample
|
|
|
308 @end defun
|
|
|
309
|
|
|
310 @node MS-DOS Subprocesses
|
|
|
311 @section MS-DOS Subprocesses
|
|
|
312
|
|
|
313 On MS-DOS, you must indicate whether the data going to and from
|
|
|
314 a synchronous subprocess are text or binary. Text data requires
|
|
|
315 translation between the end-of-line convention used within Emacs
|
|
|
316 (a single newline character) and the convention used outside Emacs
|
|
|
317 (the two-character sequence, @sc{crlf}).
|
|
|
318
|
|
|
319 The variable @code{binary-process-input} applies to input sent to the
|
|
|
320 subprocess, and @code{binary-process-output} applies to output received
|
|
|
321 from it. A non-@code{nil} value means the data is non-text; @code{nil}
|
|
|
322 means the data is text, and calls for conversion.
|
|
|
323
|
|
|
324 @defvar binary-process-input
|
|
|
325 If this variable is @code{nil}, convert newlines to @sc{crlf} sequences in
|
|
|
326 the input to a synchronous subprocess.
|
|
|
327 @end defvar
|
|
|
328
|
|
|
329 @defvar binary-process-output
|
|
|
330 If this variable is @code{nil}, convert @sc{crlf} sequences to newlines in
|
|
|
331 the output from a synchronous subprocess.
|
|
|
332 @end defvar
|
|
|
333
|
|
|
334 @xref{Files and MS-DOS}, for related information.
|
|
|
335
|
|
|
336 @node Asynchronous Processes
|
|
|
337 @section Creating an Asynchronous Process
|
|
|
338 @cindex asynchronous subprocess
|
|
|
339
|
|
|
340 After an @dfn{asynchronous process} is created, Emacs and the Lisp
|
|
|
341 program both continue running immediately. The process may thereafter
|
|
|
342 run in parallel with Emacs, and the two may communicate with each other
|
|
|
343 using the functions described in following sections. Here we describe
|
|
|
344 how to create an asynchronous process with @code{start-process}.
|
|
|
345
|
|
|
346 @defun start-process name buffer-or-name program &rest args
|
|
|
347 This function creates a new asynchronous subprocess and starts the
|
|
|
348 program @var{program} running in it. It returns a process object that
|
|
|
349 stands for the new subprocess in Lisp. The argument @var{name}
|
|
|
350 specifies the name for the process object; if a process with this name
|
|
|
351 already exists, then @var{name} is modified (by adding @samp{<1>}, etc.)
|
|
|
352 to be unique. The buffer @var{buffer-or-name} is the buffer to
|
|
|
353 associate with the process.
|
|
|
354
|
|
|
355 The remaining arguments, @var{args}, are strings that specify command
|
|
|
356 line arguments for the program.
|
|
|
357
|
|
|
358 In the example below, the first process is started and runs (rather,
|
|
|
359 sleeps) for 100 seconds. Meanwhile, the second process is started, and
|
|
|
360 given the name @samp{my-process<1>} for the sake of uniqueness. It
|
|
|
361 inserts the directory listing at the end of the buffer @samp{foo},
|
|
|
362 before the first process finishes. Then it finishes, and a message to
|
|
|
363 that effect is inserted in the buffer. Much later, the first process
|
|
|
364 finishes, and another message is inserted in the buffer for it.
|
|
|
365
|
|
|
366 @smallexample
|
|
|
367 @group
|
|
|
368 (start-process "my-process" "foo" "sleep" "100")
|
|
|
369 @result{} #<process my-process>
|
|
|
370 @end group
|
|
|
371
|
|
|
372 @group
|
|
|
373 (start-process "my-process" "foo" "ls" "-l" "/user/lewis/bin")
|
|
|
374 @result{} #<process my-process<1>>
|
|
|
375
|
|
|
376 ---------- Buffer: foo ----------
|
|
|
377 total 2
|
|
|
378 lrwxrwxrwx 1 lewis 14 Jul 22 10:12 gnuemacs --> /emacs
|
|
|
379 -rwxrwxrwx 1 lewis 19 Jul 30 21:02 lemon
|
|
|
380
|
|
|
381 Process my-process<1> finished
|
|
|
382
|
|
|
383 Process my-process finished
|
|
|
384 ---------- Buffer: foo ----------
|
|
|
385 @end group
|
|
|
386 @end smallexample
|
|
|
387 @end defun
|
|
|
388
|
|
|
389 @defun start-process-shell-command name buffer-or-name command &rest command-args
|
|
|
390 This function is like @code{start-process} except that it uses a shell
|
|
|
391 to execute the specified command. The argument @var{command} is a shell
|
|
|
392 command name, and @var{command-args} are the arguments for the shell
|
|
|
393 command.
|
|
|
394 @end defun
|
|
|
395
|
|
|
396 @defvar process-connection-type
|
|
|
397 @cindex pipes
|
|
|
398 @cindex @sc{pty}s
|
|
|
399 This variable controls the type of device used to communicate with
|
|
|
400 asynchronous subprocesses. If it is non-@code{nil}, then @sc{pty}s are
|
|
|
401 used, when available. Otherwise, pipes are used.
|
|
|
402
|
|
|
403 @sc{pty}s are usually preferable for processes visible to the user, as
|
|
|
404 in Shell mode, because they allow job control (@kbd{C-c}, @kbd{C-z},
|
|
|
405 etc.) to work between the process and its children whereas pipes do not.
|
|
|
406 For subprocesses used for internal purposes by programs, it is often
|
|
|
407 better to use a pipe, because they are more efficient. In addition, the
|
|
|
408 total number of @sc{pty}s is limited on many systems and it is good not
|
|
|
409 to waste them.
|
|
|
410
|
|
|
411 The value @code{process-connection-type} is used when
|
|
|
412 @code{start-process} is called. So you can specify how to communicate
|
|
|
413 with one subprocess by binding the variable around the call to
|
|
|
414 @code{start-process}.
|
|
|
415
|
|
|
416 @smallexample
|
|
|
417 @group
|
|
|
418 (let ((process-connection-type nil)) ; @r{Use a pipe.}
|
|
|
419 (start-process @dots{}))
|
|
|
420 @end group
|
|
|
421 @end smallexample
|
|
|
422
|
|
|
423 To determine whether a given subprocess actually got a pipe or a
|
|
|
424 @sc{pty}, use the function @code{process-tty-name} (@pxref{Process
|
|
|
425 Information}).
|
|
|
426 @end defvar
|
|
|
427
|
|
|
428 @node Deleting Processes
|
|
|
429 @section Deleting Processes
|
|
|
430 @cindex deleting processes
|
|
|
431
|
|
|
432 @dfn{Deleting a process} disconnects XEmacs immediately from the
|
|
|
433 subprocess, and removes it from the list of active processes. It sends
|
|
|
434 a signal to the subprocess to make the subprocess terminate, but this is
|
|
|
435 not guaranteed to happen immediately. The process object itself
|
|
|
436 continues to exist as long as other Lisp objects point to it.
|
|
|
437
|
|
|
438 You can delete a process explicitly at any time. Processes are
|
|
|
439 deleted automatically after they terminate, but not necessarily right
|
|
|
440 away. If you delete a terminated process explicitly before it is
|
|
|
441 deleted automatically, no harm results.
|
|
|
442
|
|
|
443 @defvar delete-exited-processes
|
|
|
444 This variable controls automatic deletion of processes that have
|
|
|
445 terminated (due to calling @code{exit} or to a signal). If it is
|
|
|
446 @code{nil}, then they continue to exist until the user runs
|
|
|
447 @code{list-processes}. Otherwise, they are deleted immediately after
|
|
|
448 they exit.
|
|
|
449 @end defvar
|
|
|
450
|
|
|
451 @defun delete-process name
|
|
|
452 This function deletes the process associated with @var{name}, killing it
|
|
|
453 with a @code{SIGHUP} signal. The argument @var{name} may be a process,
|
|
|
454 the name of a process, a buffer, or the name of a buffer.
|
|
|
455
|
|
|
456 @smallexample
|
|
|
457 @group
|
|
|
458 (delete-process "*shell*")
|
|
|
459 @result{} nil
|
|
|
460 @end group
|
|
|
461 @end smallexample
|
|
|
462 @end defun
|
|
|
463
|
|
|
464 @defun process-kill-without-query process &optional require-query-p
|
|
|
465 This function declares that XEmacs need not query the user if
|
|
|
466 @var{process} is still running when XEmacs is exited. The process will
|
|
|
467 be deleted silently. If @var{require-query-p} is non-@code{nil},
|
|
|
468 then XEmacs @emph{will} query the user (this is the default). The
|
|
|
469 return value is @code{t} if a query was formerly required, and
|
|
|
470 @code{nil} otherwise.
|
|
|
471
|
|
|
472 @smallexample
|
|
|
473 @group
|
|
|
474 (process-kill-without-query (get-process "shell"))
|
|
|
475 @result{} t
|
|
|
476 @end group
|
|
|
477 @end smallexample
|
|
|
478 @end defun
|
|
|
479
|
|
|
480 @node Process Information
|
|
|
481 @section Process Information
|
|
|
482
|
|
|
483 Several functions return information about processes.
|
|
|
484 @code{list-processes} is provided for interactive use.
|
|
|
485
|
|
|
486 @deffn Command list-processes
|
|
|
487 This command displays a listing of all living processes. In addition,
|
|
|
488 it finally deletes any process whose status was @samp{Exited} or
|
|
|
489 @samp{Signaled}. It returns @code{nil}.
|
|
|
490 @end deffn
|
|
|
491
|
|
|
492 @defun process-list
|
|
|
493 This function returns a list of all processes that have not been deleted.
|
|
|
494
|
|
|
495 @smallexample
|
|
|
496 @group
|
|
|
497 (process-list)
|
|
|
498 @result{} (#<process display-time> #<process shell>)
|
|
|
499 @end group
|
|
|
500 @end smallexample
|
|
|
501 @end defun
|
|
|
502
|
|
|
503 @defun get-process name
|
|
|
504 This function returns the process named @var{name}, or @code{nil} if
|
|
|
505 there is none. An error is signaled if @var{name} is not a string.
|
|
|
506
|
|
|
507 @smallexample
|
|
|
508 @group
|
|
|
509 (get-process "shell")
|
|
|
510 @result{} #<process shell>
|
|
|
511 @end group
|
|
|
512 @end smallexample
|
|
|
513 @end defun
|
|
|
514
|
|
|
515 @defun process-command process
|
|
|
516 This function returns the command that was executed to start
|
|
|
517 @var{process}. This is a list of strings, the first string being the
|
|
|
518 program executed and the rest of the strings being the arguments that
|
|
|
519 were given to the program.
|
|
|
520
|
|
|
521 @smallexample
|
|
|
522 @group
|
|
|
523 (process-command (get-process "shell"))
|
|
|
524 @result{} ("/bin/csh" "-i")
|
|
|
525 @end group
|
|
|
526 @end smallexample
|
|
|
527 @end defun
|
|
|
528
|
|
|
529 @defun process-id process
|
|
|
530 This function returns the @sc{pid} of @var{process}. This is an
|
|
|
531 integer that distinguishes the process @var{process} from all other
|
|
|
532 processes running on the same computer at the current time. The
|
|
|
533 @sc{pid} of a process is chosen by the operating system kernel when the
|
|
|
534 process is started and remains constant as long as the process exists.
|
|
|
535 @end defun
|
|
|
536
|
|
|
537 @defun process-name process
|
|
|
538 This function returns the name of @var{process}.
|
|
|
539 @end defun
|
|
|
540
|
|
|
541 @defun process-status process-name
|
|
|
542 This function returns the status of @var{process-name} as a symbol.
|
|
|
543 The argument @var{process-name} must be a process, a buffer, a
|
|
|
544 process name (string) or a buffer name (string).
|
|
|
545
|
|
|
546 The possible values for an actual subprocess are:
|
|
|
547
|
|
|
548 @table @code
|
|
|
549 @item run
|
|
|
550 for a process that is running.
|
|
|
551 @item stop
|
|
|
552 for a process that is stopped but continuable.
|
|
|
553 @item exit
|
|
|
554 for a process that has exited.
|
|
|
555 @item signal
|
|
|
556 for a process that has received a fatal signal.
|
|
|
557 @item open
|
|
|
558 for a network connection that is open.
|
|
|
559 @item closed
|
|
|
560 for a network connection that is closed. Once a connection
|
|
|
561 is closed, you cannot reopen it, though you might be able to open
|
|
|
562 a new connection to the same place.
|
|
|
563 @item nil
|
|
|
564 if @var{process-name} is not the name of an existing process.
|
|
|
565 @end table
|
|
|
566
|
|
|
567 @smallexample
|
|
|
568 @group
|
|
|
569 (process-status "shell")
|
|
|
570 @result{} run
|
|
|
571 @end group
|
|
|
572 @group
|
|
|
573 (process-status (get-buffer "*shell*"))
|
|
|
574 @result{} run
|
|
|
575 @end group
|
|
|
576 @group
|
|
|
577 x
|
|
|
578 @result{} #<process xx<1>>
|
|
|
579 (process-status x)
|
|
|
580 @result{} exit
|
|
|
581 @end group
|
|
|
582 @end smallexample
|
|
|
583
|
|
|
584 For a network connection, @code{process-status} returns one of the symbols
|
|
|
585 @code{open} or @code{closed}. The latter means that the other side
|
|
|
586 closed the connection, or XEmacs did @code{delete-process}.
|
|
|
587
|
|
|
588 In earlier Emacs versions (prior to version 19), the status of a network
|
|
|
589 connection was @code{run} if open, and @code{exit} if closed.
|
|
|
590 @end defun
|
|
|
591
|
|
|
592 @defun process-kill-without-query-p process
|
|
|
593 This function returns whether @var{process} will be killed without
|
|
|
594 querying the user, if it is running when XEmacs is exited. The default
|
|
|
595 value is @code{nil}.
|
|
|
596 @end defun
|
|
|
597
|
|
|
598 @defun process-exit-status process
|
|
|
599 This function returns the exit status of @var{process} or the signal
|
|
|
600 number that killed it. (Use the result of @code{process-status} to
|
|
|
601 determine which of those it is.) If @var{process} has not yet
|
|
|
602 terminated, the value is 0.
|
|
|
603 @end defun
|
|
|
604
|
|
|
605 @defun process-tty-name process
|
|
|
606 This function returns the terminal name that @var{process} is using for
|
|
|
607 its communication with Emacs---or @code{nil} if it is using pipes
|
|
|
608 instead of a terminal (see @code{process-connection-type} in
|
|
|
609 @ref{Asynchronous Processes}).
|
|
|
610 @end defun
|
|
|
611
|
|
|
612 @node Input to Processes
|
|
|
613 @section Sending Input to Processes
|
|
|
614 @cindex process input
|
|
|
615
|
|
|
616 Asynchronous subprocesses receive input when it is sent to them by
|
|
|
617 XEmacs, which is done with the functions in this section. You must
|
|
|
618 specify the process to send input to, and the input data to send. The
|
|
|
619 data appears on the ``standard input'' of the subprocess.
|
|
|
620
|
|
|
621 Some operating systems have limited space for buffered input in a
|
|
|
622 @sc{pty}. On these systems, Emacs sends an @sc{eof} periodically amidst
|
|
|
623 the other characters, to force them through. For most programs,
|
|
|
624 these @sc{eof}s do no harm.
|
|
|
625
|
|
|
626 @defun process-send-string process-name string
|
|
|
627 This function sends @var{process-name} the contents of @var{string} as
|
|
|
628 standard input. The argument @var{process-name} must be a process or
|
|
|
629 the name of a process. If it is @code{nil}, the current buffer's
|
|
|
630 process is used.
|
|
|
631
|
|
|
632 The function returns @code{nil}.
|
|
|
633
|
|
|
634 @smallexample
|
|
|
635 @group
|
|
|
636 (process-send-string "shell<1>" "ls\n")
|
|
|
637 @result{} nil
|
|
|
638 @end group
|
|
|
639
|
|
|
640
|
|
|
641 @group
|
|
|
642 ---------- Buffer: *shell* ----------
|
|
|
643 ...
|
|
|
644 introduction.texi syntax-tables.texi~
|
|
|
645 introduction.texi~ text.texi
|
|
|
646 introduction.txt text.texi~
|
|
|
647 ...
|
|
|
648 ---------- Buffer: *shell* ----------
|
|
|
649 @end group
|
|
|
650 @end smallexample
|
|
|
651 @end defun
|
|
|
652
|
|
|
653 @deffn Command process-send-region process-name start end
|
|
|
654 This function sends the text in the region defined by @var{start} and
|
|
|
655 @var{end} as standard input to @var{process-name}, which is a process or
|
|
|
656 a process name. (If it is @code{nil}, the current buffer's process is
|
|
|
657 used.)
|
|
|
658
|
|
|
659 An error is signaled unless both @var{start} and @var{end} are
|
|
|
660 integers or markers that indicate positions in the current buffer. (It
|
|
|
661 is unimportant which number is larger.)
|
|
|
662 @end deffn
|
|
|
663
|
|
|
664 @defun process-send-eof &optional process-name
|
|
|
665 This function makes @var{process-name} see an end-of-file in its
|
|
|
666 input. The @sc{eof} comes after any text already sent to it.
|
|
|
667
|
|
|
668 If @var{process-name} is not supplied, or if it is @code{nil}, then
|
|
|
669 this function sends the @sc{eof} to the current buffer's process. An
|
|
|
670 error is signaled if the current buffer has no process.
|
|
|
671
|
|
|
672 The function returns @var{process-name}.
|
|
|
673
|
|
|
674 @smallexample
|
|
|
675 @group
|
|
|
676 (process-send-eof "shell")
|
|
|
677 @result{} "shell"
|
|
|
678 @end group
|
|
|
679 @end smallexample
|
|
|
680 @end defun
|
|
|
681
|
|
|
682 @node Signals to Processes
|
|
|
683 @section Sending Signals to Processes
|
|
|
684 @cindex process signals
|
|
|
685 @cindex sending signals
|
|
|
686 @cindex signals
|
|
|
687
|
|
|
688 @dfn{Sending a signal} to a subprocess is a way of interrupting its
|
|
|
689 activities. There are several different signals, each with its own
|
|
|
690 meaning. The set of signals and their names is defined by the operating
|
|
|
691 system. For example, the signal @code{SIGINT} means that the user has
|
|
|
692 typed @kbd{C-c}, or that some analogous thing has happened.
|
|
|
693
|
|
|
694 Each signal has a standard effect on the subprocess. Most signals
|
|
|
695 kill the subprocess, but some stop or resume execution instead. Most
|
|
|
696 signals can optionally be handled by programs; if the program handles
|
|
|
697 the signal, then we can say nothing in general about its effects.
|
|
|
698
|
|
|
699 The set of signals and their names is defined by the operating system;
|
|
|
700 XEmacs has facilities for sending only a few of the signals that are
|
|
|
701 defined. XEmacs can send signals only to its own subprocesses.
|
|
|
702
|
|
|
703 You can send signals explicitly by calling the functions in this
|
|
|
704 section. XEmacs also sends signals automatically at certain times:
|
|
|
705 killing a buffer sends a @code{SIGHUP} signal to all its associated
|
|
|
706 processes; killing XEmacs sends a @code{SIGHUP} signal to all remaining
|
|
|
707 processes. (@code{SIGHUP} is a signal that usually indicates that the
|
|
|
708 user hung up the phone.)
|
|
|
709
|
|
|
710 Each of the signal-sending functions takes two optional arguments:
|
|
|
711 @var{process-name} and @var{current-group}.
|
|
|
712
|
|
|
713 The argument @var{process-name} must be either a process, the name of
|
|
|
714 one, or @code{nil}. If it is @code{nil}, the process defaults to the
|
|
|
715 process associated with the current buffer. An error is signaled if
|
|
|
716 @var{process-name} does not identify a process.
|
|
|
717
|
|
|
718 The argument @var{current-group} is a flag that makes a difference
|
|
|
719 when you are running a job-control shell as an XEmacs subprocess. If it
|
|
|
720 is non-@code{nil}, then the signal is sent to the current process-group
|
|
|
721 of the terminal that XEmacs uses to communicate with the subprocess. If
|
|
|
722 the process is a job-control shell, this means the shell's current
|
|
|
723 subjob. If it is @code{nil}, the signal is sent to the process group of
|
|
|
724 the immediate subprocess of XEmacs. If the subprocess is a job-control
|
|
|
725 shell, this is the shell itself.
|
|
|
726
|
|
|
727 The flag @var{current-group} has no effect when a pipe is used to
|
|
|
728 communicate with the subprocess, because the operating system does not
|
|
|
729 support the distinction in the case of pipes. For the same reason,
|
|
|
730 job-control shells won't work when a pipe is used. See
|
|
|
731 @code{process-connection-type} in @ref{Asynchronous Processes}.
|
|
|
732
|
|
|
733 @defun interrupt-process &optional process-name current-group
|
|
|
734 This function interrupts the process @var{process-name} by sending the
|
|
|
735 signal @code{SIGINT}. Outside of XEmacs, typing the ``interrupt
|
|
|
736 character'' (normally @kbd{C-c} on some systems, and @code{DEL} on
|
|
|
737 others) sends this signal. When the argument @var{current-group} is
|
|
|
738 non-@code{nil}, you can think of this function as ``typing @kbd{C-c}''
|
|
|
739 on the terminal by which XEmacs talks to the subprocess.
|
|
|
740 @end defun
|
|
|
741
|
|
|
742 @defun kill-process &optional process-name current-group
|
|
|
743 This function kills the process @var{process-name} by sending the
|
|
|
744 signal @code{SIGKILL}. This signal kills the subprocess immediately,
|
|
|
745 and cannot be handled by the subprocess.
|
|
|
746 @end defun
|
|
|
747
|
|
|
748 @defun quit-process &optional process-name current-group
|
|
|
749 This function sends the signal @code{SIGQUIT} to the process
|
|
|
750 @var{process-name}. This signal is the one sent by the ``quit
|
|
|
751 character'' (usually @kbd{C-b} or @kbd{C-\}) when you are not inside
|
|
|
752 XEmacs.
|
|
|
753 @end defun
|
|
|
754
|
|
|
755 @defun stop-process &optional process-name current-group
|
|
|
756 This function stops the process @var{process-name} by sending the
|
|
|
757 signal @code{SIGTSTP}. Use @code{continue-process} to resume its
|
|
|
758 execution.
|
|
|
759
|
|
|
760 On systems with job control, the ``stop character'' (usually @kbd{C-z})
|
|
|
761 sends this signal (outside of XEmacs). When @var{current-group} is
|
|
|
762 non-@code{nil}, you can think of this function as ``typing @kbd{C-z}''
|
|
|
763 on the terminal XEmacs uses to communicate with the subprocess.
|
|
|
764 @end defun
|
|
|
765
|
|
|
766 @defun continue-process &optional process-name current-group
|
|
|
767 This function resumes execution of the process @var{process} by sending
|
|
|
768 it the signal @code{SIGCONT}. This presumes that @var{process-name} was
|
|
|
769 stopped previously.
|
|
|
770 @end defun
|
|
|
771
|
|
|
772 @c Emacs 19 feature
|
|
|
773 @defun signal-process pid signal
|
|
|
774 This function sends a signal to process @var{pid}, which need not be
|
|
|
775 a child of XEmacs. The argument @var{signal} specifies which signal
|
|
|
776 to send; it should be an integer.
|
|
|
777 @end defun
|
|
|
778
|
|
|
779 @node Output from Processes
|
|
|
780 @section Receiving Output from Processes
|
|
|
781 @cindex process output
|
|
|
782 @cindex output from processes
|
|
|
783
|
|
|
784 There are two ways to receive the output that a subprocess writes to
|
|
|
785 its standard output stream. The output can be inserted in a buffer,
|
|
|
786 which is called the associated buffer of the process, or a function
|
|
|
787 called the @dfn{filter function} can be called to act on the output. If
|
|
|
788 the process has no buffer and no filter function, its output is
|
|
|
789 discarded.
|
|
|
790
|
|
|
791 @menu
|
|
|
792 * Process Buffers:: If no filter, output is put in a buffer.
|
|
|
793 * Filter Functions:: Filter functions accept output from the process.
|
|
|
794 * Accepting Output:: Explicitly permitting subprocess output.
|
|
|
795 Waiting for subprocess output.
|
|
|
796 @end menu
|
|
|
797
|
|
|
798 @node Process Buffers
|
|
|
799 @subsection Process Buffers
|
|
|
800
|
|
|
801 A process can (and usually does) have an @dfn{associated buffer},
|
|
|
802 which is an ordinary Emacs buffer that is used for two purposes: storing
|
|
|
803 the output from the process, and deciding when to kill the process. You
|
|
|
804 can also use the buffer to identify a process to operate on, since in
|
|
|
805 normal practice only one process is associated with any given buffer.
|
|
|
806 Many applications of processes also use the buffer for editing input to
|
|
|
807 be sent to the process, but this is not built into XEmacs Lisp.
|
|
|
808
|
|
|
809 Unless the process has a filter function (@pxref{Filter Functions}),
|
|
|
810 its output is inserted in the associated buffer. The position to insert
|
|
|
811 the output is determined by the @code{process-mark}, which is then
|
|
|
812 updated to point to the end of the text just inserted. Usually, but not
|
|
|
813 always, the @code{process-mark} is at the end of the buffer.
|
|
|
814
|
|
|
815 @defun process-buffer process
|
|
|
816 This function returns the associated buffer of the process
|
|
|
817 @var{process}.
|
|
|
818
|
|
|
819 @smallexample
|
|
|
820 @group
|
|
|
821 (process-buffer (get-process "shell"))
|
|
|
822 @result{} #<buffer *shell*>
|
|
|
823 @end group
|
|
|
824 @end smallexample
|
|
|
825 @end defun
|
|
|
826
|
|
|
827 @defun process-mark process
|
|
|
828 This function returns the process marker for @var{process}, which is the
|
|
|
829 marker that says where to insert output from the process.
|
|
|
830
|
|
|
831 If @var{process} does not have a buffer, @code{process-mark} returns a
|
|
|
832 marker that points nowhere.
|
|
|
833
|
|
|
834 Insertion of process output in a buffer uses this marker to decide where
|
|
|
835 to insert, and updates it to point after the inserted text. That is why
|
|
|
836 successive batches of output are inserted consecutively.
|
|
|
837
|
|
|
838 Filter functions normally should use this marker in the same fashion
|
|
|
839 as is done by direct insertion of output in the buffer. A good
|
|
|
840 example of a filter function that uses @code{process-mark} is found at
|
|
|
841 the end of the following section.
|
|
|
842
|
|
|
843 When the user is expected to enter input in the process buffer for
|
|
|
844 transmission to the process, the process marker is useful for
|
|
|
845 distinguishing the new input from previous output.
|
|
|
846 @end defun
|
|
|
847
|
|
|
848 @defun set-process-buffer process buffer
|
|
|
849 This function sets the buffer associated with @var{process} to
|
|
|
850 @var{buffer}. If @var{buffer} is @code{nil}, the process becomes
|
|
|
851 associated with no buffer.
|
|
|
852 @end defun
|
|
|
853
|
|
|
854 @defun get-buffer-process buffer-or-name
|
|
|
855 This function returns the process associated with @var{buffer-or-name}.
|
|
|
856 If there are several processes associated with it, then one is chosen.
|
|
|
857 (Presently, the one chosen is the one most recently created.) It is
|
|
|
858 usually a bad idea to have more than one process associated with the
|
|
|
859 same buffer.
|
|
|
860
|
|
|
861 @smallexample
|
|
|
862 @group
|
|
|
863 (get-buffer-process "*shell*")
|
|
|
864 @result{} #<process shell>
|
|
|
865 @end group
|
|
|
866 @end smallexample
|
|
|
867
|
|
|
868 Killing the process's buffer deletes the process, which kills the
|
|
|
869 subprocess with a @code{SIGHUP} signal (@pxref{Signals to Processes}).
|
|
|
870 @end defun
|
|
|
871
|
|
|
872 @node Filter Functions
|
|
|
873 @subsection Process Filter Functions
|
|
|
874 @cindex filter function
|
|
|
875 @cindex process filter
|
|
|
876
|
|
|
877 A process @dfn{filter function} is a function that receives the
|
|
|
878 standard output from the associated process. If a process has a filter,
|
|
|
879 then @emph{all} output from that process is passed to the filter. The
|
|
|
880 process buffer is used directly for output from the process only when
|
|
|
881 there is no filter.
|
|
|
882
|
|
|
883 A filter function must accept two arguments: the associated process and
|
|
|
884 a string, which is the output. The function is then free to do whatever it
|
|
|
885 chooses with the output.
|
|
|
886
|
|
|
887 A filter function runs only while XEmacs is waiting (e.g., for terminal
|
|
|
888 input, or for time to elapse, or for process output). This avoids the
|
|
|
889 timing errors that could result from running filters at random places in
|
|
|
890 the middle of other Lisp programs. You may explicitly cause Emacs to
|
|
|
891 wait, so that filter functions will run, by calling @code{sit-for} or
|
|
|
892 @code{sleep-for} (@pxref{Waiting}), or @code{accept-process-output}
|
|
|
893 (@pxref{Accepting Output}). Emacs is also waiting when the command loop
|
|
|
894 is reading input.
|
|
|
895
|
|
|
896 Quitting is normally inhibited within a filter function---otherwise,
|
|
|
897 the effect of typing @kbd{C-g} at command level or to quit a user
|
|
|
898 command would be unpredictable. If you want to permit quitting inside a
|
|
|
899 filter function, bind @code{inhibit-quit} to @code{nil}.
|
|
|
900 @xref{Quitting}.
|
|
|
901
|
|
|
902 If an error happens during execution of a filter function, it is
|
|
|
903 caught automatically, so that it doesn't stop the execution of whatever
|
|
|
904 program was running when the filter function was started. However, if
|
|
|
905 @code{debug-on-error} is non-@code{nil}, the error-catching is turned
|
|
|
906 off. This makes it possible to use the Lisp debugger to debug the
|
|
|
907 filter function. @xref{Debugger}.
|
|
|
908
|
|
|
909 Many filter functions sometimes or always insert the text in the
|
|
|
910 process's buffer, mimicking the actions of XEmacs when there is no
|
|
|
911 filter. Such filter functions need to use @code{set-buffer} in order to
|
|
|
912 be sure to insert in that buffer. To avoid setting the current buffer
|
|
|
913 semipermanently, these filter functions must use @code{unwind-protect}
|
|
|
914 to make sure to restore the previous current buffer. They should also
|
|
|
915 update the process marker, and in some cases update the value of point.
|
|
|
916 Here is how to do these things:
|
|
|
917
|
|
|
918 @smallexample
|
|
|
919 @group
|
|
|
920 (defun ordinary-insertion-filter (proc string)
|
|
|
921 (let ((old-buffer (current-buffer)))
|
|
|
922 (unwind-protect
|
|
|
923 (let (moving)
|
|
|
924 (set-buffer (process-buffer proc))
|
|
|
925 (setq moving (= (point) (process-mark proc)))
|
|
|
926 @end group
|
|
|
927 @group
|
|
|
928 (save-excursion
|
|
|
929 ;; @r{Insert the text, moving the process-marker.}
|
|
|
930 (goto-char (process-mark proc))
|
|
|
931 (insert string)
|
|
|
932 (set-marker (process-mark proc) (point)))
|
|
|
933 (if moving (goto-char (process-mark proc))))
|
|
|
934 (set-buffer old-buffer))))
|
|
|
935 @end group
|
|
|
936 @end smallexample
|
|
|
937
|
|
|
938 @noindent
|
|
|
939 The reason to use an explicit @code{unwind-protect} rather than letting
|
|
|
940 @code{save-excursion} restore the current buffer is so as to preserve
|
|
|
941 the change in point made by @code{goto-char}.
|
|
|
942
|
|
|
943 To make the filter force the process buffer to be visible whenever new
|
|
|
944 text arrives, insert the following line just before the
|
|
|
945 @code{unwind-protect}:
|
|
|
946
|
|
|
947 @smallexample
|
|
|
948 (display-buffer (process-buffer proc))
|
|
|
949 @end smallexample
|
|
|
950
|
|
|
951 To force point to move to the end of the new output no matter where
|
|
|
952 it was previously, eliminate the variable @code{moving} and call
|
|
|
953 @code{goto-char} unconditionally.
|
|
|
954
|
|
|
955 In earlier Emacs versions, every filter function that did regexp
|
|
|
956 searching or matching had to explicitly save and restore the match data.
|
|
|
957 Now Emacs does this automatically; filter functions never need to do it
|
|
|
958 explicitly. @xref{Match Data}.
|
|
|
959
|
|
|
960 A filter function that writes the output into the buffer of the
|
|
|
961 process should check whether the buffer is still alive. If it tries to
|
|
|
962 insert into a dead buffer, it will get an error. If the buffer is dead,
|
|
|
963 @code{(buffer-name (process-buffer @var{process}))} returns @code{nil}.
|
|
|
964
|
|
|
965 The output to the function may come in chunks of any size. A program
|
|
|
966 that produces the same output twice in a row may send it as one batch
|
|
|
967 of 200 characters one time, and five batches of 40 characters the next.
|
|
|
968
|
|
|
969 @defun set-process-filter process filter
|
|
|
970 This function gives @var{process} the filter function @var{filter}. If
|
|
|
971 @var{filter} is @code{nil}, then the process will have no filter. If
|
|
|
972 @var{filter} is @code{t}, then no output from the process will be
|
|
|
973 accepted until the filter is changed. (Output received during this
|
|
|
974 time is not discarded, but is queued, and will be processed as soon
|
|
|
975 as the filter is changed.)
|
|
|
976 @end defun
|
|
|
977
|
|
|
978 @defun process-filter process
|
|
|
979 This function returns the filter function of @var{process}, or @code{nil}
|
|
|
980 if it has none. @code{t} means that output processing has been stopped.
|
|
|
981 @end defun
|
|
|
982
|
|
|
983 Here is an example of use of a filter function:
|
|
|
984
|
|
|
985 @smallexample
|
|
|
986 @group
|
|
|
987 (defun keep-output (process output)
|
|
|
988 (setq kept (cons output kept)))
|
|
|
989 @result{} keep-output
|
|
|
990 @end group
|
|
|
991 @group
|
|
|
992 (setq kept nil)
|
|
|
993 @result{} nil
|
|
|
994 @end group
|
|
|
995 @group
|
|
|
996 (set-process-filter (get-process "shell") 'keep-output)
|
|
|
997 @result{} keep-output
|
|
|
998 @end group
|
|
|
999 @group
|
|
|
1000 (process-send-string "shell" "ls ~/other\n")
|
|
|
1001 @result{} nil
|
|
|
1002 kept
|
|
|
1003 @result{} ("lewis@@slug[8] % "
|
|
|
1004 @end group
|
|
|
1005 @group
|
|
|
1006 "FINAL-W87-SHORT.MSS backup.otl kolstad.mss~
|
|
|
1007 address.txt backup.psf kolstad.psf
|
|
|
1008 backup.bib~ david.mss resume-Dec-86.mss~
|
|
|
1009 backup.err david.psf resume-Dec.psf
|
|
|
1010 backup.mss dland syllabus.mss
|
|
|
1011 "
|
|
|
1012 "#backups.mss# backup.mss~ kolstad.mss
|
|
|
1013 ")
|
|
|
1014 @end group
|
|
|
1015 @end smallexample
|
|
|
1016
|
|
|
1017 @ignore @c The code in this example doesn't show the right way to do things.
|
|
|
1018 Here is another, more realistic example, which demonstrates how to use
|
|
|
1019 the process mark to do insertion in the same fashion as is done when
|
|
|
1020 there is no filter function:
|
|
|
1021
|
|
|
1022 @smallexample
|
|
|
1023 @group
|
|
|
1024 ;; @r{Insert input in the buffer specified by @code{my-shell-buffer}}
|
|
|
1025 ;; @r{and make sure that buffer is shown in some window.}
|
|
|
1026 (defun my-process-filter (proc str)
|
|
|
1027 (let ((cur (selected-window))
|
|
|
1028 (pop-up-windows t))
|
|
|
1029 (pop-to-buffer my-shell-buffer)
|
|
|
1030 @end group
|
|
|
1031 @group
|
|
|
1032 (goto-char (point-max))
|
|
|
1033 (insert str)
|
|
|
1034 (set-marker (process-mark proc) (point-max))
|
|
|
1035 (select-window cur)))
|
|
|
1036 @end group
|
|
|
1037 @end smallexample
|
|
|
1038 @end ignore
|
|
|
1039
|
|
|
1040 @node Accepting Output
|
|
|
1041 @subsection Accepting Output from Processes
|
|
|
1042
|
|
|
1043 Output from asynchronous subprocesses normally arrives only while
|
|
|
1044 XEmacs is waiting for some sort of external event, such as elapsed time
|
|
|
1045 or terminal input. Occasionally it is useful in a Lisp program to
|
|
|
1046 explicitly permit output to arrive at a specific point, or even to wait
|
|
|
1047 until output arrives from a process.
|
|
|
1048
|
|
|
1049 @defun accept-process-output &optional process seconds millisec
|
|
|
1050 This function allows XEmacs to read pending output from processes. The
|
|
|
1051 output is inserted in the associated buffers or given to their filter
|
|
|
1052 functions. If @var{process} is non-@code{nil} then this function does
|
|
|
1053 not return until some output has been received from @var{process}.
|
|
|
1054
|
|
|
1055 @c Emacs 19 feature
|
|
|
1056 The arguments @var{seconds} and @var{millisec} let you specify timeout
|
|
|
1057 periods. The former specifies a period measured in seconds and the
|
|
|
1058 latter specifies one measured in milliseconds. The two time periods
|
|
|
1059 thus specified are added together, and @code{accept-process-output}
|
|
|
1060 returns after that much time whether or not there has been any
|
|
|
1061 subprocess output. Note that @var{seconds} is allowed to be a
|
|
|
1062 floating-point number; thus, there is no need to ever use
|
|
|
1063 @var{millisec}. (It is retained for compatibility purposes.)
|
|
|
1064 @ignore Not in XEmacs
|
|
|
1065
|
|
|
1066 The argument @var{seconds} need not be an integer. If it is a floating
|
|
|
1067 point number, this function waits for a fractional number of seconds.
|
|
|
1068 Some systems support only a whole number of seconds; on these systems,
|
|
|
1069 @var{seconds} is rounded down. If the system doesn't support waiting
|
|
|
1070 fractions of a second, you get an error if you specify nonzero
|
|
|
1071 @var{millisec}.
|
|
|
1072
|
|
|
1073 Not all operating systems support waiting periods other than multiples
|
|
|
1074 of a second; on those that do not, you get an error if you specify
|
|
|
1075 nonzero @var{millisec}.
|
|
|
1076 @end ignore
|
|
|
1077
|
|
|
1078 The function @code{accept-process-output} returns non-@code{nil} if it
|
|
|
1079 did get some output, or @code{nil} if the timeout expired before output
|
|
|
1080 arrived.
|
|
|
1081 @end defun
|
|
|
1082
|
|
|
1083 @node Sentinels
|
|
|
1084 @section Sentinels: Detecting Process Status Changes
|
|
|
1085 @cindex process sentinel
|
|
|
1086 @cindex sentinel
|
|
|
1087
|
|
|
1088 A @dfn{process sentinel} is a function that is called whenever the
|
|
|
1089 associated process changes status for any reason, including signals
|
|
|
1090 (whether sent by XEmacs or caused by the process's own actions) that
|
|
|
1091 terminate, stop, or continue the process. The process sentinel is also
|
|
|
1092 called if the process exits. The sentinel receives two arguments: the
|
|
|
1093 process for which the event occurred, and a string describing the type
|
|
|
1094 of event.
|
|
|
1095
|
|
|
1096 The string describing the event looks like one of the following:
|
|
|
1097
|
|
|
1098 @itemize @bullet
|
|
|
1099 @item
|
|
|
1100 @code{"finished\n"}.
|
|
|
1101
|
|
|
1102 @item
|
|
|
1103 @code{"exited abnormally with code @var{exitcode}\n"}.
|
|
|
1104
|
|
|
1105 @item
|
|
|
1106 @code{"@var{name-of-signal}\n"}.
|
|
|
1107
|
|
|
1108 @item
|
|
|
1109 @code{"@var{name-of-signal} (core dumped)\n"}.
|
|
|
1110 @end itemize
|
|
|
1111
|
|
|
1112 A sentinel runs only while XEmacs is waiting (e.g., for terminal input,
|
|
|
1113 or for time to elapse, or for process output). This avoids the timing
|
|
|
1114 errors that could result from running them at random places in the
|
|
|
1115 middle of other Lisp programs. A program can wait, so that sentinels
|
|
|
1116 will run, by calling @code{sit-for} or @code{sleep-for}
|
|
|
1117 (@pxref{Waiting}), or @code{accept-process-output} (@pxref{Accepting
|
|
|
1118 Output}). Emacs is also waiting when the command loop is reading input.
|
|
|
1119
|
|
|
1120 Quitting is normally inhibited within a sentinel---otherwise, the
|
|
|
1121 effect of typing @kbd{C-g} at command level or to quit a user command
|
|
|
1122 would be unpredictable. If you want to permit quitting inside a
|
|
|
1123 sentinel, bind @code{inhibit-quit} to @code{nil}. @xref{Quitting}.
|
|
|
1124
|
|
|
1125 A sentinel that writes the output into the buffer of the process
|
|
|
1126 should check whether the buffer is still alive. If it tries to insert
|
|
|
1127 into a dead buffer, it will get an error. If the buffer is dead,
|
|
|
1128 @code{(buffer-name (process-buffer @var{process}))} returns @code{nil}.
|
|
|
1129
|
|
|
1130 If an error happens during execution of a sentinel, it is caught
|
|
|
1131 automatically, so that it doesn't stop the execution of whatever
|
|
|
1132 programs was running when the sentinel was started. However, if
|
|
|
1133 @code{debug-on-error} is non-@code{nil}, the error-catching is turned
|
|
|
1134 off. This makes it possible to use the Lisp debugger to debug the
|
|
|
1135 sentinel. @xref{Debugger}.
|
|
|
1136
|
|
|
1137 In earlier Emacs versions, every sentinel that did regexp searching or
|
|
|
1138 matching had to explicitly save and restore the match data. Now Emacs
|
|
|
1139 does this automatically; sentinels never need to do it explicitly.
|
|
|
1140 @xref{Match Data}.
|
|
|
1141
|
|
|
1142 @defun set-process-sentinel process sentinel
|
|
|
1143 This function associates @var{sentinel} with @var{process}. If
|
|
|
1144 @var{sentinel} is @code{nil}, then the process will have no sentinel.
|
|
|
1145 The default behavior when there is no sentinel is to insert a message in
|
|
|
1146 the process's buffer when the process status changes.
|
|
|
1147
|
|
|
1148 @smallexample
|
|
|
1149 @group
|
|
|
1150 (defun msg-me (process event)
|
|
|
1151 (princ
|
|
|
1152 (format "Process: %s had the event `%s'" process event)))
|
|
|
1153 (set-process-sentinel (get-process "shell") 'msg-me)
|
|
|
1154 @result{} msg-me
|
|
|
1155 @end group
|
|
|
1156 @group
|
|
|
1157 (kill-process (get-process "shell"))
|
|
|
1158 @print{} Process: #<process shell> had the event `killed'
|
|
|
1159 @result{} #<process shell>
|
|
|
1160 @end group
|
|
|
1161 @end smallexample
|
|
|
1162 @end defun
|
|
|
1163
|
|
|
1164 @defun process-sentinel process
|
|
|
1165 This function returns the sentinel of @var{process}, or @code{nil} if it
|
|
|
1166 has none.
|
|
|
1167 @end defun
|
|
|
1168
|
|
|
1169 @defun waiting-for-user-input-p
|
|
|
1170 While a sentinel or filter function is running, this function returns
|
|
|
1171 non-@code{nil} if XEmacs was waiting for keyboard input from the user at
|
|
|
1172 the time the sentinel or filter function was called, @code{nil} if it
|
|
|
1173 was not.
|
|
|
1174 @end defun
|
|
|
1175
|
|
|
1176 @c XEmacs feature
|
|
|
1177 @node Process Window Size
|
|
|
1178 @section Process Window Size
|
|
|
1179 @cindex process window size
|
|
|
1180
|
|
|
1181 @defun set-process-window-size process height width
|
|
|
1182 This function tells @var{process} that its logical window size is
|
|
|
1183 @var{height} by @var{width} characters. This is principally useful
|
|
|
1184 with pty's.
|
|
|
1185 @end defun
|
|
|
1186
|
|
|
1187 @node Transaction Queues
|
|
|
1188 @section Transaction Queues
|
|
|
1189 @cindex transaction queue
|
|
|
1190
|
|
|
1191 You can use a @dfn{transaction queue} for more convenient communication
|
|
|
1192 with subprocesses using transactions. First use @code{tq-create} to
|
|
|
1193 create a transaction queue communicating with a specified process. Then
|
|
|
1194 you can call @code{tq-enqueue} to send a transaction.
|
|
|
1195
|
|
|
1196 @defun tq-create process
|
|
|
1197 This function creates and returns a transaction queue communicating with
|
|
|
1198 @var{process}. The argument @var{process} should be a subprocess
|
|
|
1199 capable of sending and receiving streams of bytes. It may be a child
|
|
|
1200 process, or it may be a TCP connection to a server, possibly on another
|
|
|
1201 machine.
|
|
|
1202 @end defun
|
|
|
1203
|
|
|
1204 @defun tq-enqueue queue question regexp closure fn
|
|
|
1205 This function sends a transaction to queue @var{queue}. Specifying the
|
|
|
1206 queue has the effect of specifying the subprocess to talk to.
|
|
|
1207
|
|
|
1208 The argument @var{question} is the outgoing message that starts the
|
|
|
1209 transaction. The argument @var{fn} is the function to call when the
|
|
|
1210 corresponding answer comes back; it is called with two arguments:
|
|
|
1211 @var{closure}, and the answer received.
|
|
|
1212
|
|
|
1213 The argument @var{regexp} is a regular expression that should match the
|
|
|
1214 entire answer, but nothing less; that's how @code{tq-enqueue} determines
|
|
|
1215 where the answer ends.
|
|
|
1216
|
|
|
1217 The return value of @code{tq-enqueue} itself is not meaningful.
|
|
|
1218 @end defun
|
|
|
1219
|
|
|
1220 @defun tq-close queue
|
|
|
1221 Shut down transaction queue @var{queue}, waiting for all pending transactions
|
|
|
1222 to complete, and then terminate the connection or child process.
|
|
|
1223 @end defun
|
|
|
1224
|
|
|
1225 Transaction queues are implemented by means of a filter function.
|
|
|
1226 @xref{Filter Functions}.
|
|
|
1227
|
|
|
1228 @node Network
|
|
|
1229 @section Network Connections
|
|
|
1230 @cindex network connection
|
|
|
1231 @cindex TCP
|
|
|
1232
|
|
|
1233 XEmacs Lisp programs can open TCP network connections to other processes on
|
|
|
1234 the same machine or other machines. A network connection is handled by Lisp
|
|
|
1235 much like a subprocess, and is represented by a process object.
|
|
|
1236 However, the process you are communicating with is not a child of the
|
|
|
1237 XEmacs process, so you can't kill it or send it signals. All you can do
|
|
|
1238 is send and receive data. @code{delete-process} closes the connection,
|
|
|
1239 but does not kill the process at the other end; that process must decide
|
|
|
1240 what to do about closure of the connection.
|
|
|
1241
|
|
|
1242 You can distinguish process objects representing network connections
|
|
|
1243 from those representing subprocesses with the @code{process-status}
|
|
|
1244 function. It always returns either @code{open} or @code{closed} for a
|
|
|
1245 network connection, and it never returns either of those values for a
|
|
|
1246 real subprocess. @xref{Process Information}.
|
|
|
1247
|
|
|
1248 @defun open-network-stream name buffer-or-name host service
|
|
|
1249 This function opens a TCP connection for a service to a host. It
|
|
|
1250 returns a process object to represent the connection.
|
|
|
1251
|
|
|
1252 The @var{name} argument specifies the name for the process object. It
|
|
|
1253 is modified as necessary to make it unique.
|
|
|
1254
|
|
|
1255 The @var{buffer-or-name} argument is the buffer to associate with the
|
|
|
1256 connection. Output from the connection is inserted in the buffer,
|
|
|
1257 unless you specify a filter function to handle the output. If
|
|
|
1258 @var{buffer-or-name} is @code{nil}, it means that the connection is not
|
|
|
1259 associated with any buffer.
|
|
|
1260
|
|
|
1261 The arguments @var{host} and @var{service} specify where to connect to;
|
|
|
1262 @var{host} is the host name or IP address (a string), and @var{service}
|
|
|
1263 is the name of a defined network service (a string) or a port number (an
|
|
|
1264 integer).
|
|
|
1265 @end defun
|
