428
|
1 @c -*-texinfo-*-
|
|
2 @c This is part of the XEmacs Lisp Reference Manual.
|
444
|
3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
|
428
|
4 @c See the file lispref.texi for copying conditions.
|
|
5 @setfilename ../../info/os.info
|
|
6 @node System Interface, X-Windows, Processes, Top
|
|
7 @chapter Operating System Interface
|
|
8
|
|
9 This chapter is about starting and getting out of Emacs, access to
|
|
10 values in the operating system environment, and terminal input, output,
|
|
11 and flow control.
|
|
12
|
|
13 @xref{Building XEmacs}, for related information. See also
|
|
14 @ref{Display}, for additional operating system status information
|
|
15 pertaining to the terminal and the screen.
|
|
16
|
|
17 @menu
|
|
18 * Starting Up:: Customizing XEmacs start-up processing.
|
|
19 * Getting Out:: How exiting works (permanent or temporary).
|
|
20 * System Environment:: Distinguish the name and kind of system.
|
|
21 * User Identification:: Finding the name and user id of the user.
|
|
22 * Time of Day:: Getting the current time.
|
|
23 * Time Conversion:: Converting a time from numeric form to a string, or
|
|
24 to calendrical data (or vice versa).
|
|
25 * Timers:: Setting a timer to call a function at a certain time.
|
|
26 * Terminal Input:: Recording terminal input for debugging.
|
|
27 * Terminal Output:: Recording terminal output for debugging.
|
|
28 * Flow Control:: How to turn output flow control on or off.
|
|
29 * Batch Mode:: Running XEmacs without terminal interaction.
|
|
30 @end menu
|
|
31 @ignore
|
|
32 * Special Keysyms:: Defining system-specific key symbols for X windows.
|
|
33 @end ignore
|
|
34
|
|
35 @node Starting Up
|
|
36 @section Starting Up XEmacs
|
|
37
|
|
38 This section describes what XEmacs does when it is started, and how you
|
|
39 can customize these actions.
|
|
40
|
|
41 @menu
|
|
42 * Start-up Summary:: Sequence of actions XEmacs performs at start-up.
|
|
43 * Init File:: Details on reading the init file (@file{.emacs}).
|
|
44 * Terminal-Specific:: How the terminal-specific Lisp file is read.
|
|
45 * Command Line Arguments:: How command line arguments are processed,
|
|
46 and how you can customize them.
|
|
47 @end menu
|
|
48
|
|
49 @node Start-up Summary
|
|
50 @subsection Summary: Sequence of Actions at Start Up
|
|
51 @cindex initialization
|
|
52 @cindex start up of XEmacs
|
|
53 @cindex @file{startup.el}
|
|
54
|
|
55 The order of operations performed (in @file{startup.el}) by XEmacs when
|
|
56 it is started up is as follows:
|
|
57
|
|
58 @enumerate
|
|
59 @item
|
|
60 It loads the initialization library for the window system, if you are
|
|
61 using a window system. This library's name is
|
|
62 @file{term/@var{windowsystem}-win.el}.
|
|
63
|
|
64 @item
|
|
65 It processes the initial options. (Some of them are handled
|
|
66 even earlier than this.)
|
|
67
|
|
68 @item
|
|
69 It initializes the X window frame and faces, if appropriate.
|
|
70
|
|
71 @item
|
|
72 It runs the normal hook @code{before-init-hook}.
|
|
73
|
|
74 @item
|
|
75 It loads the library @file{site-start}, unless the option
|
|
76 @samp{-no-site-file} was specified. The library's file name is usually
|
|
77 @file{site-start.el}.
|
|
78 @cindex @file{site-start.el}
|
|
79
|
444
|
80 @item
|
428
|
81 It loads the file @file{~/.emacs} unless @samp{-q} was specified on
|
|
82 the command line. (This is not done in @samp{-batch} mode.) The @samp{-u}
|
|
83 option can specify the user name whose home directory should be used
|
|
84 instead of @file{~}.
|
|
85
|
444
|
86 @item
|
428
|
87 It loads the library @file{default} unless @code{inhibit-default-init}
|
|
88 is non-@code{nil}. (This is not done in @samp{-batch} mode or if
|
|
89 @samp{-q} was specified on the command line.) The library's file name
|
|
90 is usually @file{default.el}.
|
|
91 @cindex @file{default.el}
|
|
92
|
|
93 @item
|
|
94 It runs the normal hook @code{after-init-hook}.
|
|
95
|
|
96 @item
|
|
97 It sets the major mode according to @code{initial-major-mode}, provided
|
|
98 the buffer @samp{*scratch*} is still current and still in Fundamental
|
|
99 mode.
|
|
100
|
444
|
101 @item
|
428
|
102 It loads the terminal-specific Lisp file, if any, except when in batch
|
|
103 mode or using a window system.
|
|
104
|
|
105 @item
|
|
106 It displays the initial echo area message, unless you have suppressed
|
|
107 that with @code{inhibit-startup-echo-area-message}.
|
|
108
|
444
|
109 @item
|
428
|
110 It processes the action arguments from the command line.
|
|
111
|
444
|
112 @item
|
428
|
113 It runs @code{term-setup-hook}.
|
|
114
|
|
115 @item
|
|
116 It calls @code{frame-notice-user-settings}, which modifies the
|
|
117 parameters of the selected frame according to whatever the init files
|
|
118 specify.
|
|
119
|
444
|
120 @item
|
428
|
121 It runs @code{window-setup-hook}. @xref{Terminal-Specific}.
|
|
122
|
444
|
123 @item
|
428
|
124 It displays copyleft, nonwarranty, and basic use information, provided
|
|
125 there were no remaining command line arguments (a few steps above) and
|
|
126 the value of @code{inhibit-startup-message} is @code{nil}.
|
|
127 @end enumerate
|
|
128
|
|
129 @defopt inhibit-startup-message
|
|
130 This variable inhibits the initial startup messages (the nonwarranty,
|
|
131 etc.). If it is non-@code{nil}, then the messages are not printed.
|
|
132
|
|
133 This variable exists so you can set it in your personal init file, once
|
|
134 you are familiar with the contents of the startup message. Do not set
|
|
135 this variable in the init file of a new user, or in a way that affects
|
|
136 more than one user, because that would prevent new users from receiving
|
|
137 the information they are supposed to see.
|
|
138 @end defopt
|
|
139
|
|
140 @defopt inhibit-startup-echo-area-message
|
|
141 This variable controls the display of the startup echo area message.
|
|
142 You can suppress the startup echo area message by adding text with this
|
|
143 form to your @file{.emacs} file:
|
|
144
|
|
145 @example
|
|
146 (setq inhibit-startup-echo-area-message
|
|
147 "@var{your-login-name}")
|
|
148 @end example
|
|
149
|
|
150 Simply setting @code{inhibit-startup-echo-area-message} to your login
|
|
151 name is not sufficient to inhibit the message; Emacs explicitly checks
|
|
152 whether @file{.emacs} contains an expression as shown above. Your login
|
|
153 name must appear in the expression as a Lisp string constant.
|
|
154
|
|
155 This way, you can easily inhibit the message for yourself if you wish,
|
|
156 but thoughtless copying of your @file{.emacs} file will not inhibit the
|
|
157 message for someone else.
|
|
158 @end defopt
|
|
159
|
|
160 @node Init File
|
|
161 @subsection The Init File: @file{.emacs}
|
|
162 @cindex init file
|
|
163 @cindex @file{.emacs}
|
|
164
|
|
165 When you start XEmacs, it normally attempts to load the file
|
|
166 @file{.emacs} from your home directory. This file, if it exists, must
|
|
167 contain Lisp code. It is called your @dfn{init file}. The command line
|
|
168 switches @samp{-q} and @samp{-u} affect the use of the init file;
|
|
169 @samp{-q} says not to load an init file, and @samp{-u} says to load a
|
|
170 specified user's init file instead of yours. @xref{Entering XEmacs,,,
|
|
171 xemacs, The XEmacs User's Manual}.
|
|
172
|
|
173 @cindex default init file
|
|
174 A site may have a @dfn{default init file}, which is the library named
|
|
175 @file{default.el}. XEmacs finds the @file{default.el} file through the
|
|
176 standard search path for libraries (@pxref{How Programs Do Loading}).
|
|
177 The XEmacs distribution does not come with this file; sites may provide
|
|
178 one for local customizations. If the default init file exists, it is
|
|
179 loaded whenever you start Emacs, except in batch mode or if @samp{-q} is
|
|
180 specified. But your own personal init file, if any, is loaded first; if
|
|
181 it sets @code{inhibit-default-init} to a non-@code{nil} value, then
|
|
182 XEmacs does not subsequently load the @file{default.el} file.
|
|
183
|
|
184 Another file for site-customization is @file{site-start.el}. Emacs
|
|
185 loads this @emph{before} the user's init file. You can inhibit the
|
|
186 loading of this file with the option @samp{-no-site-file}.
|
|
187
|
|
188 @defvar site-run-file
|
|
189 This variable specifies the site-customization file to load
|
|
190 before the user's init file. Its normal value is @code{"site-start"}.
|
|
191 @end defvar
|
|
192
|
|
193 If there is a great deal of code in your @file{.emacs} file, you
|
|
194 should move it into another file named @file{@var{something}.el},
|
|
195 byte-compile it (@pxref{Byte Compilation}), and make your @file{.emacs}
|
|
196 file load the other file using @code{load} (@pxref{Loading}).
|
|
197
|
|
198 @xref{Init File Examples,,, xemacs, The XEmacs User's Manual}, for
|
|
199 examples of how to make various commonly desired customizations in your
|
|
200 @file{.emacs} file.
|
|
201
|
|
202 @defopt inhibit-default-init
|
|
203 This variable prevents XEmacs from loading the default initialization
|
|
204 library file for your session of XEmacs. If its value is non-@code{nil},
|
|
205 then the default library is not loaded. The default value is
|
|
206 @code{nil}.
|
|
207 @end defopt
|
|
208
|
|
209 @defvar before-init-hook
|
|
210 @defvarx after-init-hook
|
|
211 These two normal hooks are run just before, and just after, loading of
|
|
212 the user's init file, @file{default.el}, and/or @file{site-start.el}.
|
|
213 @end defvar
|
|
214
|
|
215 @node Terminal-Specific
|
|
216 @subsection Terminal-Specific Initialization
|
|
217 @cindex terminal-specific initialization
|
|
218
|
|
219 Each terminal type can have its own Lisp library that XEmacs loads when
|
|
220 run on that type of terminal. For a terminal type named @var{termtype},
|
|
221 the library is called @file{term/@var{termtype}}. XEmacs finds the file
|
|
222 by searching the @code{load-path} directories as it does for other
|
|
223 files, and trying the @samp{.elc} and @samp{.el} suffixes. Normally,
|
|
224 terminal-specific Lisp library is located in @file{emacs/lisp/term}, a
|
|
225 subdirectory of the @file{emacs/lisp} directory in which most XEmacs Lisp
|
|
226 libraries are kept.@refill
|
|
227
|
|
228 The library's name is constructed by concatenating the value of the
|
|
229 variable @code{term-file-prefix} and the terminal type. Normally,
|
|
230 @code{term-file-prefix} has the value @code{"term/"}; changing this
|
|
231 is not recommended.
|
|
232
|
|
233 The usual function of a terminal-specific library is to enable special
|
|
234 keys to send sequences that XEmacs can recognize. It may also need to
|
|
235 set or add to @code{function-key-map} if the Termcap entry does not
|
|
236 specify all the terminal's function keys. @xref{Terminal Input}.
|
|
237
|
|
238 @cindex Termcap
|
|
239 When the name of the terminal type contains a hyphen, only the part of
|
|
240 the name before the first hyphen is significant in choosing the library
|
|
241 name. Thus, terminal types @samp{aaa-48} and @samp{aaa-30-rv} both use
|
|
242 the @file{term/aaa} library. If necessary, the library can evaluate
|
|
243 @code{(getenv "TERM")} to find the full name of the terminal
|
|
244 type.@refill
|
|
245
|
|
246 Your @file{.emacs} file can prevent the loading of the
|
|
247 terminal-specific library by setting the variable
|
|
248 @code{term-file-prefix} to @code{nil}. This feature is useful when
|
|
249 experimenting with your own peculiar customizations.
|
|
250
|
|
251 You can also arrange to override some of the actions of the
|
|
252 terminal-specific library by setting the variable
|
|
253 @code{term-setup-hook}. This is a normal hook which XEmacs runs using
|
|
254 @code{run-hooks} at the end of XEmacs initialization, after loading both
|
|
255 your @file{.emacs} file and any terminal-specific libraries. You can
|
|
256 use this variable to define initializations for terminals that do not
|
|
257 have their own libraries. @xref{Hooks}.
|
|
258
|
|
259 @defvar term-file-prefix
|
|
260 @cindex @code{TERM} environment variable
|
|
261 If the @code{term-file-prefix} variable is non-@code{nil}, XEmacs loads
|
|
262 a terminal-specific initialization file as follows:
|
|
263
|
|
264 @example
|
|
265 (load (concat term-file-prefix (getenv "TERM")))
|
|
266 @end example
|
|
267
|
|
268 @noindent
|
|
269 You may set the @code{term-file-prefix} variable to @code{nil} in your
|
|
270 @file{.emacs} file if you do not wish to load the
|
|
271 terminal-initialization file. To do this, put the following in
|
|
272 your @file{.emacs} file: @code{(setq term-file-prefix nil)}.
|
|
273 @end defvar
|
|
274
|
444
|
275 @defvar term-setup-hook
|
428
|
276 This variable is a normal hook that XEmacs runs after loading your
|
|
277 @file{.emacs} file, the default initialization file (if any) and the
|
|
278 terminal-specific Lisp file.
|
|
279
|
|
280 You can use @code{term-setup-hook} to override the definitions made by a
|
|
281 terminal-specific file.
|
|
282 @end defvar
|
|
283
|
|
284 @defvar window-setup-hook
|
|
285 This variable is a normal hook which XEmacs runs after loading your
|
|
286 @file{.emacs} file and the default initialization file (if any), after
|
|
287 loading terminal-specific Lisp code, and after running the hook
|
|
288 @code{term-setup-hook}.
|
|
289 @end defvar
|
|
290
|
|
291 @node Command Line Arguments
|
|
292 @subsection Command Line Arguments
|
|
293 @cindex command line arguments
|
|
294
|
|
295 You can use command line arguments to request various actions when you
|
|
296 start XEmacs. Since you do not need to start XEmacs more than once per
|
|
297 day, and will often leave your XEmacs session running longer than that,
|
|
298 command line arguments are hardly ever used. As a practical matter, it
|
|
299 is best to avoid making the habit of using them, since this habit would
|
|
300 encourage you to kill and restart XEmacs unnecessarily often. These
|
|
301 options exist for two reasons: to be compatible with other editors (for
|
|
302 invocation by other programs) and to enable shell scripts to run
|
|
303 specific Lisp programs.
|
|
304
|
|
305 This section describes how Emacs processes command line arguments,
|
|
306 and how you can customize them.
|
|
307
|
|
308 @ignore
|
|
309 (Note that some other editors require you to start afresh each time
|
|
310 you want to edit a file. With this kind of editor, you will probably
|
|
311 specify the file as a command line argument. The recommended way to
|
|
312 use XEmacs is to start it only once, just after you log in, and do
|
|
313 all your editing in the same XEmacs process. Each time you want to edit
|
|
314 a different file, you visit it with the existing XEmacs, which eventually
|
|
315 comes to have many files in it ready for editing. Usually you do not
|
|
316 kill the XEmacs until you are about to log out.)
|
|
317 @end ignore
|
|
318
|
|
319 @defun command-line
|
|
320 This function parses the command line that XEmacs was called with,
|
|
321 processes it, loads the user's @file{.emacs} file and displays the
|
|
322 startup messages.
|
|
323 @end defun
|
|
324
|
|
325 @defvar command-line-processed
|
|
326 The value of this variable is @code{t} once the command line has been
|
|
327 processed.
|
|
328
|
|
329 If you redump XEmacs by calling @code{dump-emacs}, you may wish to set
|
|
330 this variable to @code{nil} first in order to cause the new dumped XEmacs
|
|
331 to process its new command line arguments.
|
|
332 @end defvar
|
|
333
|
|
334 @defvar command-switch-alist
|
|
335 @cindex switches on command line
|
|
336 @cindex options on command line
|
|
337 @cindex command line options
|
|
338 The value of this variable is an alist of user-defined command-line
|
|
339 options and associated handler functions. This variable exists so you
|
|
340 can add elements to it.
|
|
341
|
|
342 A @dfn{command line option} is an argument on the command line of the
|
|
343 form:
|
|
344
|
|
345 @example
|
|
346 -@var{option}
|
|
347 @end example
|
|
348
|
444
|
349 The elements of the @code{command-switch-alist} look like this:
|
428
|
350
|
|
351 @example
|
|
352 (@var{option} . @var{handler-function})
|
|
353 @end example
|
|
354
|
|
355 The @var{handler-function} is called to handle @var{option} and receives
|
|
356 the option name as its sole argument.
|
|
357
|
|
358 In some cases, the option is followed in the command line by an
|
|
359 argument. In these cases, the @var{handler-function} can find all the
|
|
360 remaining command-line arguments in the variable
|
|
361 @code{command-line-args-left}. (The entire list of command-line
|
|
362 arguments is in @code{command-line-args}.)
|
|
363
|
|
364 The command line arguments are parsed by the @code{command-line-1}
|
|
365 function in the @file{startup.el} file. See also @ref{Command
|
|
366 Switches, , Command Line Switches and Arguments, xemacs, The XEmacs
|
|
367 User's Manual}.
|
|
368 @end defvar
|
|
369
|
|
370 @defvar command-line-args
|
|
371 The value of this variable is the list of command line arguments passed
|
|
372 to XEmacs.
|
|
373 @end defvar
|
|
374
|
|
375 @defvar command-line-functions
|
|
376 This variable's value is a list of functions for handling an
|
|
377 unrecognized command-line argument. Each time the next argument to be
|
|
378 processed has no special meaning, the functions in this list are called,
|
|
379 in order of appearance, until one of them returns a non-@code{nil}
|
|
380 value.
|
|
381
|
|
382 These functions are called with no arguments. They can access the
|
|
383 command-line argument under consideration through the variable
|
|
384 @code{argi}. The remaining arguments (not including the current one)
|
|
385 are in the variable @code{command-line-args-left}.
|
|
386
|
|
387 When a function recognizes and processes the argument in @code{argi}, it
|
|
388 should return a non-@code{nil} value to say it has dealt with that
|
|
389 argument. If it has also dealt with some of the following arguments, it
|
|
390 can indicate that by deleting them from @code{command-line-args-left}.
|
|
391
|
|
392 If all of these functions return @code{nil}, then the argument is used
|
|
393 as a file name to visit.
|
|
394 @end defvar
|
|
395
|
|
396 @node Getting Out
|
|
397 @section Getting out of XEmacs
|
|
398 @cindex exiting XEmacs
|
|
399
|
|
400 There are two ways to get out of XEmacs: you can kill the XEmacs job,
|
|
401 which exits permanently, or you can suspend it, which permits you to
|
|
402 reenter the XEmacs process later. As a practical matter, you seldom kill
|
|
403 XEmacs---only when you are about to log out. Suspending is much more
|
|
404 common.
|
|
405
|
|
406 @menu
|
|
407 * Killing XEmacs:: Exiting XEmacs irreversibly.
|
|
408 * Suspending XEmacs:: Exiting XEmacs reversibly.
|
|
409 @end menu
|
|
410
|
|
411 @node Killing XEmacs
|
|
412 @subsection Killing XEmacs
|
|
413 @cindex killing XEmacs
|
|
414
|
|
415 Killing XEmacs means ending the execution of the XEmacs process. The
|
|
416 parent process normally resumes control. The low-level primitive for
|
|
417 killing XEmacs is @code{kill-emacs}.
|
|
418
|
444
|
419 @deffn Command kill-emacs &optional exit-data
|
428
|
420 This function exits the XEmacs process and kills it.
|
|
421
|
|
422 If @var{exit-data} is an integer, then it is used as the exit status
|
|
423 of the XEmacs process. (This is useful primarily in batch operation; see
|
|
424 @ref{Batch Mode}.)
|
|
425
|
|
426 If @var{exit-data} is a string, its contents are stuffed into the
|
|
427 terminal input buffer so that the shell (or whatever program next reads
|
|
428 input) can read them.
|
444
|
429 @end deffn
|
428
|
430
|
|
431 All the information in the XEmacs process, aside from files that have
|
|
432 been saved, is lost when the XEmacs is killed. Because killing XEmacs
|
|
433 inadvertently can lose a lot of work, XEmacs queries for confirmation
|
|
434 before actually terminating if you have buffers that need saving or
|
|
435 subprocesses that are running. This is done in the function
|
|
436 @code{save-buffers-kill-emacs}.
|
|
437
|
|
438 @defvar kill-emacs-query-functions
|
|
439 After asking the standard questions, @code{save-buffers-kill-emacs}
|
|
440 calls the functions in the list @code{kill-buffer-query-functions}, in
|
|
441 order of appearance, with no arguments. These functions can ask for
|
|
442 additional confirmation from the user. If any of them returns
|
|
443 non-@code{nil}, XEmacs is not killed.
|
|
444 @end defvar
|
|
445
|
|
446 @defvar kill-emacs-hook
|
|
447 This variable is a normal hook; once @code{save-buffers-kill-emacs} is
|
|
448 finished with all file saving and confirmation, it runs the functions in
|
|
449 this hook.
|
|
450 @end defvar
|
|
451
|
|
452 @node Suspending XEmacs
|
|
453 @subsection Suspending XEmacs
|
|
454 @cindex suspending XEmacs
|
|
455
|
|
456 @dfn{Suspending XEmacs} means stopping XEmacs temporarily and returning
|
|
457 control to its superior process, which is usually the shell. This
|
|
458 allows you to resume editing later in the same XEmacs process, with the
|
|
459 same buffers, the same kill ring, the same undo history, and so on. To
|
|
460 resume XEmacs, use the appropriate command in the parent shell---most
|
|
461 likely @code{fg}.
|
|
462
|
|
463 Some operating systems do not support suspension of jobs; on these
|
|
464 systems, ``suspension'' actually creates a new shell temporarily as a
|
|
465 subprocess of XEmacs. Then you would exit the shell to return to XEmacs.
|
|
466
|
|
467 Suspension is not useful with window systems such as X, because the
|
|
468 XEmacs job may not have a parent that can resume it again, and in any
|
|
469 case you can give input to some other job such as a shell merely by
|
|
470 moving to a different window. Therefore, suspending is not allowed
|
|
471 when XEmacs is an X client.
|
|
472
|
444
|
473 @deffn Command suspend-emacs &optional stuffstring
|
428
|
474 This function stops XEmacs and returns control to the superior process.
|
|
475 If and when the superior process resumes XEmacs, @code{suspend-emacs}
|
|
476 returns @code{nil} to its caller in Lisp.
|
|
477
|
444
|
478 If optional arg @var{stuffstring} is non-@code{nil}, its characters are
|
|
479 sent to be read as terminal input by XEmacs's superior shell. The
|
|
480 characters in @var{stuffstring} are not echoed by the superior shell;
|
|
481 only the results appear.
|
428
|
482
|
|
483 Before suspending, @code{suspend-emacs} runs the normal hook
|
|
484 @code{suspend-hook}. In Emacs version 18, @code{suspend-hook} was not a
|
|
485 normal hook; its value was a single function, and if its value was
|
|
486 non-@code{nil}, then @code{suspend-emacs} returned immediately without
|
|
487 actually suspending anything.
|
|
488
|
|
489 After the user resumes XEmacs, @code{suspend-emacs} runs the normal hook
|
|
490 @code{suspend-resume-hook}. @xref{Hooks}.
|
|
491
|
|
492 The next redisplay after resumption will redraw the entire screen,
|
|
493 unless the variable @code{no-redraw-on-reenter} is non-@code{nil}
|
|
494 (@pxref{Refresh Screen}).
|
|
495
|
|
496 In the following example, note that @samp{pwd} is not echoed after
|
|
497 XEmacs is suspended. But it is read and executed by the shell.
|
|
498
|
|
499 @smallexample
|
|
500 @group
|
|
501 (suspend-emacs)
|
|
502 @result{} nil
|
|
503 @end group
|
|
504
|
|
505 @group
|
|
506 (add-hook 'suspend-hook
|
|
507 (function (lambda ()
|
|
508 (or (y-or-n-p
|
|
509 "Really suspend? ")
|
|
510 (error "Suspend cancelled")))))
|
|
511 @result{} (lambda nil
|
|
512 (or (y-or-n-p "Really suspend? ")
|
|
513 (error "Suspend cancelled")))
|
|
514 @end group
|
|
515 @group
|
|
516 (add-hook 'suspend-resume-hook
|
|
517 (function (lambda () (message "Resumed!"))))
|
|
518 @result{} (lambda nil (message "Resumed!"))
|
|
519 @end group
|
|
520 @group
|
|
521 (suspend-emacs "pwd")
|
|
522 @result{} nil
|
|
523 @end group
|
|
524 @group
|
|
525 ---------- Buffer: Minibuffer ----------
|
|
526 Really suspend? @kbd{y}
|
|
527 ---------- Buffer: Minibuffer ----------
|
|
528 @end group
|
|
529
|
|
530 @group
|
|
531 ---------- Parent Shell ----------
|
|
532 lewis@@slug[23] % /user/lewis/manual
|
|
533 lewis@@slug[24] % fg
|
|
534 @end group
|
|
535
|
|
536 @group
|
|
537 ---------- Echo Area ----------
|
|
538 Resumed!
|
|
539 @end group
|
|
540 @end smallexample
|
444
|
541 @end deffn
|
428
|
542
|
|
543 @defvar suspend-hook
|
|
544 This variable is a normal hook run before suspending.
|
|
545 @end defvar
|
|
546
|
|
547 @defvar suspend-resume-hook
|
|
548 This variable is a normal hook run after suspending.
|
|
549 @end defvar
|
|
550
|
|
551 @node System Environment
|
|
552 @section Operating System Environment
|
|
553 @cindex operating system environment
|
|
554
|
|
555 XEmacs provides access to variables in the operating system environment
|
|
556 through various functions. These variables include the name of the
|
|
557 system, the user's @sc{uid}, and so on.
|
|
558
|
|
559 @defvar system-type
|
|
560 The value of this variable is a symbol indicating the type of operating
|
|
561 system XEmacs is operating on. Here is a table of the possible values:
|
|
562
|
|
563 @table @code
|
|
564 @item aix-v3
|
|
565 AIX.
|
|
566
|
|
567 @item berkeley-unix
|
|
568 Berkeley BSD.
|
|
569
|
|
570 @item dgux
|
|
571 Data General DGUX operating system.
|
|
572
|
|
573 @item gnu
|
|
574 A GNU system using the GNU HURD and Mach.
|
|
575
|
|
576 @item hpux
|
|
577 Hewlett-Packard HPUX operating system.
|
|
578
|
|
579 @item irix
|
|
580 Silicon Graphics Irix system.
|
|
581
|
|
582 @item linux
|
|
583 A GNU system using the Linux kernel.
|
|
584
|
|
585 @item ms-dos
|
|
586 Microsoft MS-DOS ``operating system.''
|
|
587
|
|
588 @item next-mach
|
|
589 NeXT Mach-based system.
|
|
590
|
|
591 @item rtu
|
|
592 Masscomp RTU, UCB universe.
|
|
593
|
|
594 @item unisoft-unix
|
|
595 UniSoft UniPlus.
|
|
596
|
|
597 @item usg-unix-v
|
|
598 AT&T System V.
|
|
599
|
|
600 @item windows-nt
|
|
601 Microsoft windows NT.
|
|
602
|
|
603 @item xenix
|
|
604 SCO Xenix 386.
|
|
605 @end table
|
|
606
|
|
607 We do not wish to add new symbols to make finer distinctions unless it
|
|
608 is absolutely necessary! In fact, we hope to eliminate some of these
|
|
609 alternatives in the future. We recommend using
|
|
610 @code{system-configuration} to distinguish between different operating
|
|
611 systems.
|
|
612 @end defvar
|
|
613
|
|
614 @defvar system-configuration
|
|
615 This variable holds the three-part configuration name for the
|
|
616 hardware/software configuration of your system, as a string. The
|
|
617 convenient way to test parts of this string is with @code{string-match}.
|
|
618 @end defvar
|
|
619
|
|
620 @defun system-name
|
|
621 This function returns the name of the machine you are running on.
|
|
622 @example
|
|
623 (system-name)
|
|
624 @result{} "prep.ai.mit.edu"
|
|
625 @end example
|
|
626 @end defun
|
|
627
|
|
628 @vindex system-name
|
|
629 The symbol @code{system-name} is a variable as well as a function. In
|
|
630 fact, the function returns whatever value the variable
|
|
631 @code{system-name} currently holds. Thus, you can set the variable
|
|
632 @code{system-name} in case Emacs is confused about the name of your
|
|
633 system. The variable is also useful for constructing frame titles
|
|
634 (@pxref{Frame Titles}).
|
|
635
|
|
636 @defvar mail-host-address
|
|
637 If this variable is non-@code{nil}, it is used instead of
|
|
638 @code{system-name} for purposes of generating email addresses. For
|
|
639 example, it is used when constructing the default value of
|
|
640 @code{user-mail-address}. @xref{User Identification}. (Since this is
|
|
641 done when XEmacs starts up, the value actually used is the one saved when
|
|
642 XEmacs was dumped. @xref{Building XEmacs}.)
|
|
643 @end defvar
|
|
644
|
444
|
645 @deffn Command getenv var &optional interactivep
|
428
|
646 @cindex environment variable access
|
|
647 This function returns the value of the environment variable @var{var},
|
|
648 as a string. Within XEmacs, the environment variable values are kept in
|
|
649 the Lisp variable @code{process-environment}.
|
|
650
|
444
|
651 When invoked interactively, @code{getenv} prints the value in the echo area.
|
|
652
|
428
|
653 @example
|
|
654 @group
|
|
655 (getenv "USER")
|
|
656 @result{} "lewis"
|
|
657 @end group
|
|
658
|
|
659 @group
|
|
660 lewis@@slug[10] % printenv
|
|
661 PATH=.:/user/lewis/bin:/usr/bin:/usr/local/bin
|
|
662 USER=lewis
|
|
663 @end group
|
|
664 @group
|
|
665 TERM=ibmapa16
|
|
666 SHELL=/bin/csh
|
|
667 HOME=/user/lewis
|
|
668 @end group
|
|
669 @end example
|
444
|
670 @end deffn
|
428
|
671
|
444
|
672 @deffn Command setenv variable &optional value unset
|
428
|
673 This command sets the value of the environment variable named
|
|
674 @var{variable} to @var{value}. Both arguments should be strings. This
|
|
675 function works by modifying @code{process-environment}; binding that
|
|
676 variable with @code{let} is also reasonable practice.
|
|
677 @end deffn
|
|
678
|
|
679 @defvar process-environment
|
|
680 This variable is a list of strings, each describing one environment
|
444
|
681 variable. The functions @code{getenv} and @code{setenv} work by
|
|
682 manipulating this variable.
|
428
|
683
|
|
684 @smallexample
|
|
685 @group
|
|
686 process-environment
|
|
687 @result{} ("l=/usr/stanford/lib/gnuemacs/lisp"
|
|
688 "PATH=.:/user/lewis/bin:/usr/class:/nfsusr/local/bin"
|
444
|
689 "USER=lewis"
|
428
|
690 @end group
|
|
691 @group
|
444
|
692 "TERM=ibmapa16"
|
428
|
693 "SHELL=/bin/csh"
|
|
694 "HOME=/user/lewis")
|
|
695 @end group
|
|
696 @end smallexample
|
|
697 @end defvar
|
|
698
|
|
699 @defvar path-separator
|
|
700 This variable holds a string which says which character separates
|
|
701 directories in a search path (as found in an environment variable). Its
|
|
702 value is @code{":"} for Unix and GNU systems, and @code{";"} for MS-DOS
|
|
703 and Windows NT.
|
|
704 @end defvar
|
|
705
|
|
706 @defvar invocation-name
|
|
707 This variable holds the program name under which Emacs was invoked. The
|
|
708 value is a string, and does not include a directory name.
|
|
709 @end defvar
|
|
710
|
|
711 @defvar invocation-directory
|
|
712 This variable holds the directory from which the Emacs executable was
|
|
713 invoked, or perhaps @code{nil} if that directory cannot be determined.
|
|
714 @end defvar
|
|
715
|
|
716 @defvar installation-directory
|
|
717 If non-@code{nil}, this is a directory within which to look for the
|
|
718 @file{lib-src} and @file{etc} subdirectories. This is non-@code{nil}
|
|
719 when Emacs can't find those directories in their standard installed
|
|
720 locations, but can find them in a directory related somehow to the one
|
|
721 containing the Emacs executable.
|
|
722 @end defvar
|
|
723
|
|
724 @defun load-average &optional use-floats
|
|
725 This function returns a list of the current 1-minute, 5-minute and
|
|
726 15-minute load averages. The values are integers that are 100 times the
|
|
727 system load averages. (The load averages indicate the number of
|
|
728 processes trying to run.)
|
|
729
|
444
|
730 When @var{use-floats} is non-@code{nil}, floats will be returned instead
|
428
|
731 of integers. These floats are not multiplied by 100.
|
|
732
|
|
733 @example
|
|
734 @group
|
|
735 (load-average)
|
|
736 @result{} (169 158 164)
|
|
737 (load-average t)
|
|
738 @result{} (1.69921875 1.58984375 1.640625)
|
|
739 @end group
|
|
740
|
|
741 @group
|
|
742 lewis@@rocky[5] % uptime
|
|
743 8:06pm up 16 day(s), 21:57, 40 users,
|
|
744 load average: 1.68, 1.59, 1.64
|
|
745 @end group
|
|
746 @end example
|
|
747
|
|
748 If the 5-minute or 15-minute load averages are not available, return a
|
|
749 shortened list, containing only those averages which are available.
|
|
750
|
444
|
751 On some systems, this function may require special privileges to run, or
|
428
|
752 it may be unimplemented for the particular system type. In that case,
|
|
753 the function will signal an error.
|
|
754 @end defun
|
|
755
|
|
756 @defun emacs-pid
|
|
757 This function returns the process @sc{id} of the Emacs process.
|
|
758 @end defun
|
|
759
|
|
760 @node User Identification
|
|
761 @section User Identification
|
|
762
|
|
763 @defvar user-mail-address
|
|
764 This holds the nominal email address of the user who is using Emacs.
|
|
765 When Emacs starts up, it computes a default value that is usually right,
|
|
766 but users often set this themselves when the default value is not right.
|
|
767 @end defvar
|
|
768
|
|
769 @defun user-login-name &optional uid
|
|
770 If you don't specify @var{uid}, this function returns the name under
|
|
771 which the user is logged in. If the environment variable @code{LOGNAME}
|
|
772 is set, that value is used. Otherwise, if the environment variable
|
|
773 @code{USER} is set, that value is used. Otherwise, the value is based
|
|
774 on the effective @sc{uid}, not the real @sc{uid}.
|
|
775
|
|
776 If you specify @var{uid}, the value is the user name that corresponds
|
|
777 to @var{uid} (which should be an integer).
|
|
778
|
|
779 @example
|
|
780 @group
|
|
781 (user-login-name)
|
|
782 @result{} "lewis"
|
|
783 @end group
|
|
784 @end example
|
|
785 @end defun
|
|
786
|
|
787 @defun user-real-login-name
|
|
788 This function returns the user name corresponding to Emacs's real
|
|
789 @sc{uid}. This ignores the effective @sc{uid} and ignores the
|
|
790 environment variables @code{LOGNAME} and @code{USER}.
|
|
791 @end defun
|
|
792
|
|
793 @defvar user-full-name
|
|
794 This variable holds the name of the user running this Emacs. It is
|
|
795 initialized at startup time from the value of @code{NAME} environment
|
444
|
796 variable. You can change the value of this variable to alter the result
|
428
|
797 of the @code{user-full-name} function.
|
|
798 @end defvar
|
|
799
|
|
800 @defun user-full-name &optional user
|
|
801 This function returns the full name of @var{user}. If @var{user} is
|
|
802 @code{nil}, it defaults to the user running this Emacs. In that case,
|
|
803 the value of @code{user-full-name} variable, if non-@code{nil}, will be
|
|
804 used.
|
|
805
|
444
|
806 If @var{user} is specified explicitly, @code{user-full-name} variable is
|
428
|
807 ignored.
|
|
808
|
|
809 @example
|
|
810 @group
|
|
811 (user-full-name)
|
|
812 @result{} "Hrvoje Niksic"
|
|
813 (setq user-full-name "Hrvoje \"Niksa\" Niksic")
|
|
814 (user-full-name)
|
|
815 @result{} "Hrvoje \"Niksa\" Niksic"
|
|
816 (user-full-name "hniksic")
|
|
817 @result{} "Hrvoje Niksic"
|
|
818 @end group
|
|
819 @end example
|
|
820 @end defun
|
|
821
|
|
822 @vindex user-full-name
|
|
823 @vindex user-real-login-name
|
|
824 @vindex user-login-name
|
|
825 The symbols @code{user-login-name}, @code{user-real-login-name} and
|
|
826 @code{user-full-name} are variables as well as functions. The functions
|
|
827 return the same values that the variables hold. These variables allow
|
|
828 you to ``fake out'' Emacs by telling the functions what to return. The
|
|
829 variables are also useful for constructing frame titles (@pxref{Frame
|
|
830 Titles}).
|
|
831
|
|
832 @defun user-real-uid
|
|
833 This function returns the real @sc{uid} of the user.
|
|
834
|
|
835 @example
|
|
836 @group
|
|
837 (user-real-uid)
|
|
838 @result{} 19
|
|
839 @end group
|
|
840 @end example
|
|
841 @end defun
|
|
842
|
|
843 @defun user-uid
|
444
|
844 This function returns the effective @sc{uid} of the user.
|
428
|
845 @end defun
|
|
846
|
|
847 @defun user-home-directory
|
|
848 This function returns the ``@code{HOME}'' directory of the user, and is
|
|
849 intended to replace occurrences of ``@code{(getenv "HOME")}''. Under
|
|
850 Unix systems, the following is done:
|
|
851
|
|
852 @enumerate
|
|
853 @item
|
|
854 Return the value of ``@code{(getenv "HOME")}'', if set.
|
|
855
|
|
856 @item
|
|
857 Return ``/'', as a fallback, but issue a warning. (Future versions of
|
|
858 XEmacs will also attempt to lookup the @code{HOME} directory via
|
|
859 @code{getpwent()}, but this has not yet been implemented.)
|
|
860 @end enumerate
|
|
861
|
|
862 Under MS Windows, this is done:
|
|
863
|
|
864 @enumerate
|
|
865 @item
|
|
866 Return the value of ``@code{(getenv "HOME")}'', if set.
|
|
867
|
|
868 @item
|
3772
|
869 If the environment variables @code{HOMEDRIVE} and @code{HOMEPATH} are
|
428
|
870 both set, return the concatenation (the following description uses MS
|
|
871 Windows environment variable substitution syntax):
|
3772
|
872 @code{%HOMEDRIVE%%HOMEPATH%}.
|
428
|
873
|
|
874 @item
|
|
875 Return ``C:\'', as a fallback, but issue a warning.
|
|
876 @end enumerate
|
|
877 @end defun
|
|
878
|
|
879 @node Time of Day
|
|
880 @section Time of Day
|
|
881
|
|
882 This section explains how to determine the current time and the time
|
|
883 zone.
|
|
884
|
|
885 @defun current-time-string &optional time-value
|
|
886 This function returns the current time and date as a humanly-readable
|
|
887 string. The format of the string is unvarying; the number of characters
|
|
888 used for each part is always the same, so you can reliably use
|
|
889 @code{substring} to extract pieces of it. It is wise to count the
|
|
890 characters from the beginning of the string rather than from the end, as
|
|
891 additional information may be added at the end.
|
|
892
|
|
893 @c Emacs 19 feature
|
|
894 The argument @var{time-value}, if given, specifies a time to format
|
|
895 instead of the current time. The argument should be a list whose first
|
|
896 two elements are integers. Thus, you can use times obtained from
|
|
897 @code{current-time} (see below) and from @code{file-attributes}
|
|
898 (@pxref{File Attributes}).
|
|
899
|
|
900 @example
|
|
901 @group
|
|
902 (current-time-string)
|
|
903 @result{} "Wed Oct 14 22:21:05 1987"
|
|
904 @end group
|
|
905 @end example
|
|
906 @end defun
|
|
907
|
|
908 @c Emacs 19 feature
|
|
909 @defun current-time
|
|
910 This function returns the system's time value as a list of three
|
|
911 integers: @code{(@var{high} @var{low} @var{microsec})}. The integers
|
|
912 @var{high} and @var{low} combine to give the number of seconds since
|
|
913 0:00 January 1, 1970, which is
|
|
914 @ifinfo
|
|
915 @var{high} * 2**16 + @var{low}.
|
|
916 @end ifinfo
|
|
917 @tex
|
|
918 $high*2^{16}+low$.
|
|
919 @end tex
|
|
920
|
|
921 The third element, @var{microsec}, gives the microseconds since the
|
|
922 start of the current second (or 0 for systems that return time only on
|
|
923 the resolution of a second).
|
|
924
|
|
925 The first two elements can be compared with file time values such as you
|
|
926 get with the function @code{file-attributes}. @xref{File Attributes}.
|
|
927 @end defun
|
|
928
|
|
929 @c Emacs 19 feature
|
|
930 @defun current-time-zone &optional time-value
|
|
931 This function returns a list describing the time zone that the user is
|
|
932 in.
|
|
933
|
|
934 The value has the form @code{(@var{offset} @var{name})}. Here
|
|
935 @var{offset} is an integer giving the number of seconds ahead of UTC
|
|
936 (east of Greenwich). A negative value means west of Greenwich. The
|
|
937 second element, @var{name} is a string giving the name of the time
|
|
938 zone. Both elements change when daylight savings time begins or ends;
|
|
939 if the user has specified a time zone that does not use a seasonal time
|
|
940 adjustment, then the value is constant through time.
|
|
941
|
|
942 If the operating system doesn't supply all the information necessary to
|
|
943 compute the value, both elements of the list are @code{nil}.
|
|
944
|
|
945 The argument @var{time-value}, if given, specifies a time to analyze
|
|
946 instead of the current time. The argument should be a cons cell
|
|
947 containing two integers, or a list whose first two elements are
|
|
948 integers. Thus, you can use times obtained from @code{current-time}
|
|
949 (see above) and from @code{file-attributes} (@pxref{File Attributes}).
|
|
950 @end defun
|
|
951
|
|
952 @node Time Conversion
|
|
953 @section Time Conversion
|
|
954
|
|
955 These functions convert time values (lists of two or three integers)
|
|
956 to strings or to calendrical information. There is also a function to
|
|
957 convert calendrical information to a time value. You can get time
|
|
958 values from the functions @code{current-time} (@pxref{Time of Day}) and
|
|
959 @code{file-attributes} (@pxref{File Attributes}).
|
|
960
|
|
961 @defun format-time-string format-string &optional time
|
|
962 This function converts @var{time} to a string according to
|
|
963 @var{format-string}. If @var{time} is omitted, it defaults to the
|
|
964 current time. The argument @var{format-string} may contain
|
|
965 @samp{%}-sequences which say to substitute parts of the time. Here is a
|
|
966 table of what the @samp{%}-sequences mean:
|
|
967
|
|
968 @table @samp
|
|
969 @item %a
|
|
970 This stands for the abbreviated name of the day of week.
|
|
971 @item %A
|
|
972 This stands for the full name of the day of week.
|
|
973 @item %b
|
|
974 This stands for the abbreviated name of the month.
|
|
975 @item %B
|
|
976 This stands for the full name of the month.
|
|
977 @item %c
|
|
978 This is a synonym for @samp{%x %X}.
|
|
979 @item %C
|
|
980 This has a locale-specific meaning. In the default locale (named C), it
|
|
981 is equivalent to @samp{%A, %B %e, %Y}.
|
|
982 @item %d
|
|
983 This stands for the day of month, zero-padded.
|
|
984 @item %D
|
|
985 This is a synonym for @samp{%m/%d/%y}.
|
|
986 @item %e
|
|
987 This stands for the day of month, blank-padded.
|
|
988 @item %h
|
|
989 This is a synonym for @samp{%b}.
|
|
990 @item %H
|
|
991 This stands for the hour (00-23).
|
|
992 @item %I
|
|
993 This stands for the hour (00-12).
|
|
994 @item %j
|
|
995 This stands for the day of the year (001-366).
|
|
996 @item %k
|
|
997 This stands for the hour (0-23), blank padded.
|
|
998 @item %l
|
|
999 This stands for the hour (1-12), blank padded.
|
|
1000 @item %m
|
|
1001 This stands for the month (01-12).
|
|
1002 @item %M
|
|
1003 This stands for the minute (00-59).
|
|
1004 @item %n
|
|
1005 This stands for a newline.
|
|
1006 @item %p
|
|
1007 This stands for @samp{AM} or @samp{PM}, as appropriate.
|
|
1008 @item %r
|
|
1009 This is a synonym for @samp{%I:%M:%S %p}.
|
|
1010 @item %R
|
|
1011 This is a synonym for @samp{%H:%M}.
|
|
1012 @item %S
|
|
1013 This stands for the seconds (00-60).
|
|
1014 @item %t
|
|
1015 This stands for a tab character.
|
|
1016 @item %T
|
|
1017 This is a synonym for @samp{%H:%M:%S}.
|
|
1018 @item %U
|
|
1019 This stands for the week of the year (01-52), assuming that weeks
|
|
1020 start on Sunday.
|
|
1021 @item %w
|
|
1022 This stands for the numeric day of week (0-6). Sunday is day 0.
|
|
1023 @item %W
|
|
1024 This stands for the week of the year (01-52), assuming that weeks
|
|
1025 start on Monday.
|
|
1026 @item %x
|
|
1027 This has a locale-specific meaning. In the default locale (named C), it
|
|
1028 is equivalent to @samp{%D}.
|
|
1029 @item %X
|
|
1030 This has a locale-specific meaning. In the default locale (named C), it
|
|
1031 is equivalent to @samp{%T}.
|
|
1032 @item %y
|
|
1033 This stands for the year without century (00-99).
|
|
1034 @item %Y
|
|
1035 This stands for the year with century.
|
|
1036 @item %Z
|
|
1037 This stands for the time zone abbreviation.
|
|
1038 @end table
|
|
1039 @end defun
|
|
1040
|
444
|
1041 @defun decode-time &optional specified-time
|
428
|
1042 This function converts a time value into calendrical information. The
|
444
|
1043 optional @var{specified-time} should be a list of
|
|
1044 (@var{high} @var{low} . @var{ignored}) or (@var{high} . @var{low}), as from
|
|
1045 @code{current-time} and @code{file-attributes}, or @code{nil} to use the
|
|
1046 current time.
|
|
1047
|
|
1048 The return value is a list of nine elements, as follows:
|
428
|
1049
|
|
1050 @example
|
|
1051 (@var{seconds} @var{minutes} @var{hour} @var{day} @var{month} @var{year} @var{dow} @var{dst} @var{zone})
|
|
1052 @end example
|
|
1053
|
|
1054 Here is what the elements mean:
|
|
1055
|
|
1056 @table @var
|
|
1057 @item sec
|
|
1058 The number of seconds past the minute, as an integer between 0 and 59.
|
|
1059 @item minute
|
|
1060 The number of minutes past the hour, as an integer between 0 and 59.
|
|
1061 @item hour
|
|
1062 The hour of the day, as an integer between 0 and 23.
|
|
1063 @item day
|
|
1064 The day of the month, as an integer between 1 and 31.
|
|
1065 @item month
|
|
1066 The month of the year, as an integer between 1 and 12.
|
|
1067 @item year
|
|
1068 The year, an integer typically greater than 1900.
|
|
1069 @item dow
|
|
1070 The day of week, as an integer between 0 and 6, where 0 stands for
|
|
1071 Sunday.
|
|
1072 @item dst
|
|
1073 @code{t} if daylight savings time is effect, otherwise @code{nil}.
|
|
1074 @item zone
|
|
1075 An integer indicating the time zone, as the number of seconds east of
|
|
1076 Greenwich.
|
|
1077 @end table
|
|
1078
|
|
1079 Note that Common Lisp has different meanings for @var{dow} and
|
|
1080 @var{zone}.
|
|
1081 @end defun
|
|
1082
|
|
1083 @defun encode-time seconds minutes hour day month year &optional zone
|
|
1084 This function is the inverse of @code{decode-time}. It converts seven
|
|
1085 items of calendrical data into a time value. For the meanings of the
|
|
1086 arguments, see the table above under @code{decode-time}.
|
|
1087
|
|
1088 Year numbers less than 100 are treated just like other year numbers. If
|
|
1089 you want them to stand for years above 1900, you must alter them yourself
|
|
1090 before you call @code{encode-time}.
|
|
1091
|
|
1092 The optional argument @var{zone} defaults to the current time zone and
|
|
1093 its daylight savings time rules. If specified, it can be either a list
|
|
1094 (as you would get from @code{current-time-zone}) or an integer (as you
|
|
1095 would get from @code{decode-time}). The specified zone is used without
|
|
1096 any further alteration for daylight savings time.
|
|
1097 @end defun
|
|
1098
|
|
1099 @node Timers
|
|
1100 @section Timers for Delayed Execution
|
|
1101
|
|
1102 You can set up a timer to call a function at a specified future time.
|
|
1103
|
|
1104 @c All different in FSF 19
|
|
1105 @defun add-timeout secs function object &optional resignal
|
|
1106 This function adds a timeout, to be signaled after the timeout period
|
|
1107 has elapsed. @var{secs} is a number of seconds, expressed as an integer
|
|
1108 or a float. @var{function} will be called after that many seconds have
|
|
1109 elapsed, with one argument, the given @var{object}. If the optional
|
|
1110 @var{resignal} argument is provided, then after this timeout expires,
|
444
|
1111 @code{add-timeout} will automatically be called again with
|
|
1112 @var{resignal} as the first argument.
|
428
|
1113
|
|
1114 This function returns an object which is the @dfn{id} of this particular
|
|
1115 timeout. You can pass that object to @code{disable-timeout} to turn off
|
|
1116 the timeout before it has been signalled.
|
|
1117
|
|
1118 The number of seconds may be expressed as a floating-point number, in which
|
|
1119 case some fractional part of a second will be used. Caveat: the usable
|
|
1120 timeout granularity will vary from system to system.
|
|
1121
|
|
1122 Adding a timeout causes a timeout event to be returned by
|
|
1123 @code{next-event}, and the function will be invoked by
|
|
1124 @code{dispatch-event}, so if XEmacs is in a tight loop, the function will
|
|
1125 not be invoked until the next call to sit-for or until the return to
|
|
1126 top-level (the same is true of process filters).
|
|
1127
|
|
1128 WARNING: if you are thinking of calling add-timeout from inside of a
|
|
1129 callback function as a way of resignalling a timeout, think again. There
|
|
1130 is a race condition. That's why the @var{resignal} argument exists.
|
|
1131
|
|
1132 (NOTE: In FSF Emacs, this function is called @code{run-at-time} and
|
|
1133 has different semantics.)
|
|
1134 @end defun
|
|
1135
|
|
1136 @defun disable-timeout id
|
|
1137 Cancel the requested action for @var{id}, which should be a value
|
|
1138 previously returned by @code{add-timeout}. This cancels the effect of
|
|
1139 that call to @code{add-timeout}; the arrival of the specified time will
|
|
1140 not cause anything special to happen.
|
|
1141 (NOTE: In FSF Emacs, this function is called @code{cancel-timer}.)
|
|
1142 @end defun
|
|
1143
|
|
1144 @node Terminal Input
|
|
1145 @section Terminal Input
|
|
1146 @cindex terminal input
|
|
1147
|
|
1148 This section describes functions and variables for recording or
|
|
1149 manipulating terminal input. See @ref{Display}, for related
|
|
1150 functions.
|
|
1151
|
|
1152 @menu
|
|
1153 * Input Modes:: Options for how input is processed.
|
|
1154 * Translating Input:: Low level conversion of some characters or events
|
|
1155 into others.
|
|
1156 * Recording Input:: Saving histories of recent or all input events.
|
|
1157 @end menu
|
|
1158
|
|
1159 @node Input Modes
|
|
1160 @subsection Input Modes
|
|
1161 @cindex input modes
|
|
1162 @cindex terminal input modes
|
|
1163
|
444
|
1164 @defun set-input-mode interrupt flow meta &optional quit-char console
|
428
|
1165 This function sets the mode for reading keyboard input. If
|
|
1166 @var{interrupt} is non-null, then XEmacs uses input interrupts. If it is
|
|
1167 @code{nil}, then it uses @sc{cbreak} mode. When XEmacs communicates
|
|
1168 directly with X, it ignores this argument and uses interrupts if that is
|
|
1169 the way it knows how to communicate.
|
|
1170
|
|
1171 If @var{flow} is non-@code{nil}, then XEmacs uses @sc{xon/xoff} (@kbd{C-q},
|
|
1172 @kbd{C-s}) flow control for output to the terminal. This has no effect except
|
|
1173 in @sc{cbreak} mode. @xref{Flow Control}.
|
|
1174
|
|
1175 The default setting is system dependent. Some systems always use
|
|
1176 @sc{cbreak} mode regardless of what is specified.
|
|
1177
|
|
1178 @c Emacs 19 feature
|
|
1179 The argument @var{meta} controls support for input character codes
|
|
1180 above 127. If @var{meta} is @code{t}, XEmacs converts characters with
|
|
1181 the 8th bit set into Meta characters. If @var{meta} is @code{nil},
|
|
1182 XEmacs disregards the 8th bit; this is necessary when the terminal uses
|
|
1183 it as a parity bit. If @var{meta} is neither @code{t} nor @code{nil},
|
|
1184 XEmacs uses all 8 bits of input unchanged. This is good for terminals
|
|
1185 using European 8-bit character sets.
|
|
1186
|
|
1187 @c Emacs 19 feature
|
|
1188 If @var{quit-char} is non-@code{nil}, it specifies the character to
|
|
1189 use for quitting. Normally this character is @kbd{C-g}.
|
|
1190 @xref{Quitting}.
|
|
1191 @end defun
|
|
1192
|
|
1193 The @code{current-input-mode} function returns the input mode settings
|
|
1194 XEmacs is currently using.
|
|
1195
|
|
1196 @c Emacs 19 feature
|
444
|
1197 @defun current-input-mode &optional console
|
428
|
1198 This function returns current mode for reading keyboard input. It
|
|
1199 returns a list, corresponding to the arguments of @code{set-input-mode},
|
|
1200 of the form @code{(@var{interrupt} @var{flow} @var{meta} @var{quit})} in
|
|
1201 which:
|
|
1202 @table @var
|
|
1203 @item interrupt
|
|
1204 is non-@code{nil} when XEmacs is using interrupt-driven input. If
|
|
1205 @code{nil}, Emacs is using @sc{cbreak} mode.
|
|
1206 @item flow
|
|
1207 is non-@code{nil} if XEmacs uses @sc{xon/xoff} (@kbd{C-q}, @kbd{C-s})
|
|
1208 flow control for output to the terminal. This value has no effect
|
|
1209 unless @var{interrupt} is non-@code{nil}.
|
|
1210 @item meta
|
|
1211 is @code{t} if XEmacs treats the eighth bit of input characters as
|
|
1212 the meta bit; @code{nil} means XEmacs clears the eighth bit of every
|
|
1213 input character; any other value means XEmacs uses all eight bits as the
|
|
1214 basic character code.
|
|
1215 @item quit
|
|
1216 is the character XEmacs currently uses for quitting, usually @kbd{C-g}.
|
|
1217 @end table
|
|
1218 @end defun
|
|
1219
|
|
1220 @node Translating Input
|
|
1221 @subsection Translating Input Events
|
|
1222 @cindex translating input events
|
|
1223
|
|
1224 This section describes features for translating input events into other
|
|
1225 input events before they become part of key sequences.
|
|
1226
|
|
1227 @ignore Not in XEmacs yet.
|
|
1228 @c Emacs 19 feature
|
|
1229 @defvar extra-keyboard-modifiers
|
|
1230 This variable lets Lisp programs ``press'' the modifier keys on the
|
|
1231 keyboard. The value is a bit mask:
|
|
1232
|
|
1233 @table @asis
|
|
1234 @item 1
|
|
1235 The @key{SHIFT} key.
|
|
1236 @item 2
|
|
1237 The @key{LOCK} key.
|
|
1238 @item 4
|
|
1239 The @key{CTL} key.
|
|
1240 @item 8
|
|
1241 The @key{META} key.
|
|
1242 @end table
|
|
1243
|
|
1244 Each time the user types a keyboard key, it is altered as if the
|
|
1245 modifier keys specified in the bit mask were held down.
|
|
1246
|
|
1247 When using X windows, the program can ``press'' any of the modifier
|
|
1248 keys in this way. Otherwise, only the @key{CTL} and @key{META} keys can
|
|
1249 be virtually pressed.
|
|
1250 @end defvar
|
|
1251
|
|
1252 @defvar keyboard-translate-table
|
|
1253 This variable is the translate table for keyboard characters. It lets
|
|
1254 you reshuffle the keys on the keyboard without changing any command
|
|
1255 bindings. Its value must be a string or @code{nil}.
|
|
1256
|
|
1257 If @code{keyboard-translate-table} is a string, then each character read
|
|
1258 from the keyboard is looked up in this string and the character in the
|
|
1259 string is used instead. If the string is of length @var{n}, character codes
|
|
1260 @var{n} and up are untranslated.
|
|
1261
|
|
1262 In the example below, we set @code{keyboard-translate-table} to a
|
|
1263 string of 128 characters. Then we fill it in to swap the characters
|
|
1264 @kbd{C-s} and @kbd{C-\} and the characters @kbd{C-q} and @kbd{C-^}.
|
|
1265 Subsequently, typing @kbd{C-\} has all the usual effects of typing
|
|
1266 @kbd{C-s}, and vice versa. (@xref{Flow Control} for more information on
|
|
1267 this subject.)
|
|
1268
|
|
1269 @cindex flow control example
|
|
1270 @example
|
|
1271 @group
|
|
1272 (defun evade-flow-control ()
|
|
1273 "Replace C-s with C-\ and C-q with C-^."
|
|
1274 (interactive)
|
|
1275 @end group
|
|
1276 @group
|
|
1277 (let ((the-table (make-string 128 0)))
|
|
1278 (let ((i 0))
|
|
1279 (while (< i 128)
|
|
1280 (aset the-table i i)
|
|
1281 (setq i (1+ i))))
|
|
1282 @end group
|
|
1283 ;; @r{Swap @kbd{C-s} and @kbd{C-\}.}
|
|
1284 (aset the-table ?\034 ?\^s)
|
|
1285 (aset the-table ?\^s ?\034)
|
|
1286 @group
|
|
1287 ;; @r{Swap @kbd{C-q} and @kbd{C-^}.}
|
|
1288 (aset the-table ?\036 ?\^q)
|
|
1289 (aset the-table ?\^q ?\036)
|
|
1290 (setq keyboard-translate-table the-table)))
|
|
1291 @end group
|
|
1292 @end example
|
|
1293
|
|
1294 Note that this translation is the first thing that happens to a
|
|
1295 character after it is read from the terminal. Record-keeping features
|
|
1296 such as @code{recent-keys} and dribble files record the characters after
|
|
1297 translation.
|
|
1298 @end defvar
|
|
1299
|
444
|
1300 @defun keyboard-translate &rest pairs
|
428
|
1301 This function modifies @code{keyboard-translate-table} to translate
|
|
1302 character code @var{from} into character code @var{to}. It creates
|
444
|
1303 or enlarges the translate table if necessary. Multiple
|
|
1304 @var{from}-@var{to} pairs may be specified.
|
428
|
1305 @end defun
|
|
1306 @end ignore
|
|
1307
|
|
1308 @defvar function-key-map
|
|
1309 This variable holds a keymap that describes the character sequences
|
|
1310 sent by function keys on an ordinary character terminal. This keymap
|
|
1311 uses the same data structure as other keymaps, but is used differently: it
|
|
1312 specifies translations to make while reading events.
|
|
1313
|
|
1314 If @code{function-key-map} ``binds'' a key sequence @var{k} to a vector
|
|
1315 @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a
|
|
1316 key sequence, it is replaced with the events in @var{v}.
|
|
1317
|
|
1318 For example, VT100 terminals send @kbd{@key{ESC} O P} when the
|
|
1319 keypad PF1 key is pressed. Therefore, we want XEmacs to translate
|
|
1320 that sequence of events into the single event @code{pf1}. We accomplish
|
|
1321 this by ``binding'' @kbd{@key{ESC} O P} to @code{[pf1]} in
|
|
1322 @code{function-key-map}, when using a VT100.
|
|
1323
|
|
1324 Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c
|
|
1325 @key{ESC} O P}; later the function @code{read-key-sequence} translates
|
|
1326 this back into @kbd{C-c @key{PF1}}, which it returns as the vector
|
|
1327 @code{[?\C-c pf1]}.
|
|
1328
|
|
1329 Entries in @code{function-key-map} are ignored if they conflict with
|
|
1330 bindings made in the minor mode, local, or global keymaps. The intent
|
|
1331 is that the character sequences that function keys send should not have
|
|
1332 command bindings in their own right.
|
|
1333
|
|
1334 The value of @code{function-key-map} is usually set up automatically
|
|
1335 according to the terminal's Terminfo or Termcap entry, but sometimes
|
|
1336 those need help from terminal-specific Lisp files. XEmacs comes with
|
|
1337 terminal-specific files for many common terminals; their main purpose is
|
|
1338 to make entries in @code{function-key-map} beyond those that can be
|
|
1339 deduced from Termcap and Terminfo. @xref{Terminal-Specific}.
|
|
1340
|
|
1341 Emacs versions 18 and earlier used totally different means of detecting
|
|
1342 the character sequences that represent function keys.
|
|
1343 @end defvar
|
|
1344
|
|
1345 @defvar key-translation-map
|
|
1346 This variable is another keymap used just like @code{function-key-map}
|
|
1347 to translate input events into other events. It differs from
|
|
1348 @code{function-key-map} in two ways:
|
|
1349
|
|
1350 @itemize @bullet
|
|
1351 @item
|
|
1352 @code{key-translation-map} goes to work after @code{function-key-map} is
|
|
1353 finished; it receives the results of translation by
|
|
1354 @code{function-key-map}.
|
|
1355
|
|
1356 @item
|
|
1357 @code{key-translation-map} overrides actual key bindings.
|
|
1358 @end itemize
|
|
1359
|
|
1360 The intent of @code{key-translation-map} is for users to map one
|
|
1361 character set to another, including ordinary characters normally bound
|
|
1362 to @code{self-insert-command}.
|
|
1363 @end defvar
|
|
1364
|
|
1365 @cindex key translation function
|
|
1366 You can use @code{function-key-map} or @code{key-translation-map} for
|
|
1367 more than simple aliases, by using a function, instead of a key
|
|
1368 sequence, as the ``translation'' of a key. Then this function is called
|
|
1369 to compute the translation of that key.
|
|
1370
|
|
1371 The key translation function receives one argument, which is the prompt
|
|
1372 that was specified in @code{read-key-sequence}---or @code{nil} if the
|
|
1373 key sequence is being read by the editor command loop. In most cases
|
|
1374 you can ignore the prompt value.
|
|
1375
|
|
1376 If the function reads input itself, it can have the effect of altering
|
|
1377 the event that follows. For example, here's how to define @kbd{C-c h}
|
|
1378 to turn the character that follows into a Hyper character:
|
|
1379
|
|
1380 @example
|
|
1381 @group
|
|
1382 (defun hyperify (prompt)
|
|
1383 (let ((e (read-event)))
|
|
1384 (vector (if (numberp e)
|
|
1385 (logior (lsh 1 20) e)
|
|
1386 (if (memq 'hyper (event-modifiers e))
|
|
1387 e
|
|
1388 (add-event-modifier "H-" e))))))
|
|
1389
|
|
1390 (defun add-event-modifier (string e)
|
|
1391 (let ((symbol (if (symbolp e) e (car e))))
|
|
1392 (setq symbol (intern (concat string
|
|
1393 (symbol-name symbol))))
|
|
1394 @end group
|
|
1395 @group
|
|
1396 (if (symbolp e)
|
|
1397 symbol
|
|
1398 (cons symbol (cdr e)))))
|
|
1399
|
|
1400 (define-key function-key-map "\C-ch" 'hyperify)
|
|
1401 @end group
|
|
1402 @end example
|
|
1403
|
|
1404 @pindex iso-transl
|
|
1405 @cindex Latin-1 character set (input)
|
|
1406 @cindex ISO Latin-1 characters (input)
|
|
1407 The @file{iso-transl} library uses this feature to provide a way of
|
|
1408 inputting non-ASCII Latin-1 characters.
|
|
1409
|
|
1410 @node Recording Input
|
|
1411 @subsection Recording Input
|
|
1412
|
|
1413 @defun recent-keys &optional number
|
|
1414 This function returns a vector containing recent input events from the
|
|
1415 keyboard or mouse. By default, 100 events are recorded, which is how
|
|
1416 many @code{recent-keys} returns.
|
|
1417
|
|
1418 All input events are included, whether or not they were used as parts of
|
|
1419 key sequences. Thus, you always get the last 100 inputs, not counting
|
|
1420 keyboard macros. (Events from keyboard macros are excluded because they
|
|
1421 are less interesting for debugging; it should be enough to see the
|
|
1422 events that invoked the macros.)
|
|
1423
|
|
1424 If @var{number} is specified, not more than @var{number} events will be
|
|
1425 returned. You may change the number of stored events using
|
|
1426 @code{set-recent-keys-ring-size}.
|
|
1427 @end defun
|
|
1428
|
|
1429 @defun recent-keys-ring-size
|
|
1430 This function returns the number of recent events stored internally.
|
|
1431 This is also the maximum number of events @code{recent-keys} can
|
|
1432 return. By default, 100 events are stored.
|
|
1433 @end defun
|
|
1434
|
|
1435 @defun set-recent-keys-ring-size size
|
444
|
1436 This function changes the number of events stored by XEmacs and returned
|
428
|
1437 by @code{recent-keys}.
|
|
1438
|
|
1439 For example, @code{(set-recent-keys-ring-size 250)} will make XEmacs
|
|
1440 remember last 250 events and will make @code{recent-keys} return last
|
|
1441 250 events by default.
|
|
1442 @end defun
|
|
1443
|
444
|
1444 @deffn Command open-dribble-file filename
|
428
|
1445 @cindex dribble file
|
|
1446 This function opens a @dfn{dribble file} named @var{filename}. When a
|
|
1447 dribble file is open, each input event from the keyboard or mouse (but
|
|
1448 not those from keyboard macros) is written in that file. A
|
|
1449 non-character event is expressed using its printed representation
|
|
1450 surrounded by @samp{<@dots{}>}.
|
|
1451
|
|
1452 You close the dribble file by calling this function with an argument
|
|
1453 of @code{nil}.
|
|
1454
|
|
1455 This function is normally used to record the input necessary to
|
|
1456 trigger an XEmacs bug, for the sake of a bug report.
|
|
1457
|
|
1458 @example
|
|
1459 @group
|
|
1460 (open-dribble-file "~/dribble")
|
|
1461 @result{} nil
|
|
1462 @end group
|
|
1463 @end example
|
|
1464 @end deffn
|
|
1465
|
|
1466 See also the @code{open-termscript} function (@pxref{Terminal Output}).
|
|
1467
|
|
1468 @node Terminal Output
|
|
1469 @section Terminal Output
|
|
1470 @cindex terminal output
|
|
1471
|
|
1472 The terminal output functions send output to the terminal or keep
|
|
1473 track of output sent to the terminal. The function
|
|
1474 @code{device-baud-rate} tells you what XEmacs thinks is the output speed
|
|
1475 of the terminal.
|
|
1476
|
|
1477 @defun device-baud-rate &optional device
|
|
1478 This function's value is the output speed of the terminal associated
|
|
1479 with @var{device}, as far as XEmacs knows. @var{device} defaults to the
|
|
1480 selected device (usually the only device) if omitted. Changing this
|
|
1481 value does not change the speed of actual data transmission, but the
|
|
1482 value is used for calculations such as padding. This value has no
|
|
1483 effect for window-system devices. (This is different in FSF Emacs, where
|
|
1484 the baud rate also affects decisions about whether to scroll part of the
|
|
1485 screen or repaint, even when using a window system.)
|
|
1486
|
|
1487 The value is measured in bits per second.
|
|
1488 @end defun
|
|
1489
|
|
1490 XEmacs attempts to automatically initialize the baud rate by querying
|
|
1491 the terminal. If you are running across a network, however, and
|
|
1492 different parts of the network work are at different baud rates, the
|
|
1493 value returned by XEmacs may be different from the value used by your
|
|
1494 local terminal. Some network protocols communicate the local terminal
|
|
1495 speed to the remote machine, so that XEmacs and other programs can get
|
|
1496 the proper value, but others do not. If XEmacs has the wrong value, it
|
|
1497 makes decisions that are less than optimal. To fix the problem, use
|
|
1498 @code{set-device-baud-rate}.
|
|
1499
|
444
|
1500 @defun set-device-baud-rate device baud-rate
|
428
|
1501 This function sets the output speed of @var{device}. See
|
|
1502 @code{device-baud-rate}. @var{device} defaults to the selected device
|
444
|
1503 (usually the only device) if @code{nil}.
|
428
|
1504 @end defun
|
|
1505
|
|
1506 @defun send-string-to-terminal char-or-string &optional stdout-p device
|
|
1507 This function sends @var{char-or-string} to the terminal without
|
|
1508 alteration. Control characters in @var{char-or-string} have
|
|
1509 terminal-dependent effects.
|
|
1510
|
|
1511 If @var{device} is @code{nil}, this function writes to XEmacs's
|
|
1512 stderr, or to stdout if @var{stdout-p} is non-@code{nil}. Otherwise,
|
|
1513 @var{device} should be a tty or stream device, and the function writes
|
|
1514 to the device's normal or error output, according to @var{stdout-p}.
|
|
1515
|
|
1516 One use of this function is to define function keys on terminals that
|
|
1517 have downloadable function key definitions. For example, this is how on
|
|
1518 certain terminals to define function key 4 to move forward four
|
|
1519 characters (by transmitting the characters @kbd{C-u C-f} to the
|
|
1520 computer):
|
|
1521
|
|
1522 @example
|
|
1523 @group
|
|
1524 (send-string-to-terminal "\eF4\^U\^F")
|
|
1525 @result{} nil
|
|
1526 @end group
|
|
1527 @end example
|
|
1528 @end defun
|
|
1529
|
|
1530 @deffn Command open-termscript filename
|
|
1531 @cindex termscript file
|
|
1532 This function is used to open a @dfn{termscript file} that will record
|
|
1533 all the characters sent by XEmacs to the terminal. (If there are
|
|
1534 multiple tty or stream devices, all characters sent to all such devices
|
|
1535 are recorded.) The function returns @code{nil}. Termscript files are
|
|
1536 useful for investigating problems where XEmacs garbles the screen,
|
|
1537 problems that are due to incorrect Termcap entries or to undesirable
|
|
1538 settings of terminal options more often than to actual XEmacs bugs.
|
|
1539 Once you are certain which characters were actually output, you can
|
|
1540 determine reliably whether they correspond to the Termcap specifications
|
|
1541 in use.
|
|
1542
|
|
1543 A @code{nil} value for @var{filename} stops recording terminal output.
|
|
1544
|
|
1545 See also @code{open-dribble-file} in @ref{Terminal Input}.
|
|
1546
|
|
1547 @example
|
|
1548 @group
|
|
1549 (open-termscript "../junk/termscript")
|
|
1550 @result{} nil
|
|
1551 @end group
|
|
1552 @end example
|
|
1553 @end deffn
|
|
1554
|
|
1555 @ignore Not in XEmacs
|
|
1556 @node Special Keysyms
|
|
1557 @section System-Specific X11 Keysyms
|
|
1558
|
|
1559 To define system-specific X11 keysyms, set the variable
|
|
1560 @code{system-key-alist}.
|
|
1561
|
|
1562 @defvar system-key-alist
|
|
1563 This variable's value should be an alist with one element for each
|
|
1564 system-specific keysym. An element has this form: @code{(@var{code}
|
|
1565 . @var{symbol})}, where @var{code} is the numeric keysym code (not
|
|
1566 including the ``vendor specific'' bit, 1 << 28), and @var{symbol} is the
|
|
1567 name for the function key.
|
|
1568
|
|
1569 For example @code{(168 . mute-acute)} defines a system-specific key used
|
|
1570 by HP X servers whose numeric code is (1 << 28) + 168.
|
|
1571
|
|
1572 It is not a problem if the alist defines keysyms for other X servers, as
|
|
1573 long as they don't conflict with the ones used by the X server actually
|
|
1574 in use.
|
|
1575
|
|
1576 The variable is always local to the current X terminal and cannot be
|
|
1577 buffer-local. @xref{Multiple Displays}.
|
|
1578 @end defvar
|
|
1579 @end ignore
|
|
1580
|
|
1581 @node Flow Control
|
|
1582 @section Flow Control
|
|
1583 @cindex flow control characters
|
|
1584
|
|
1585 This section attempts to answer the question ``Why does XEmacs choose
|
|
1586 to use flow-control characters in its command character set?'' For a
|
|
1587 second view on this issue, read the comments on flow control in the
|
|
1588 @file{emacs/INSTALL} file from the distribution; for help with Termcap
|
|
1589 entries and DEC terminal concentrators, see @file{emacs/etc/TERMS}.
|
|
1590
|
|
1591 @cindex @kbd{C-s}
|
|
1592 @cindex @kbd{C-q}
|
|
1593 At one time, most terminals did not need flow control, and none used
|
|
1594 @code{C-s} and @kbd{C-q} for flow control. Therefore, the choice of
|
|
1595 @kbd{C-s} and @kbd{C-q} as command characters was uncontroversial.
|
|
1596 XEmacs, for economy of keystrokes and portability, used nearly all the
|
|
1597 @sc{ascii} control characters, with mnemonic meanings when possible;
|
|
1598 thus, @kbd{C-s} for search and @kbd{C-q} for quote.
|
|
1599
|
|
1600 Later, some terminals were introduced which required these characters
|
|
1601 for flow control. They were not very good terminals for full-screen
|
|
1602 editing, so XEmacs maintainers did not pay attention. In later years,
|
|
1603 flow control with @kbd{C-s} and @kbd{C-q} became widespread among
|
|
1604 terminals, but by this time it was usually an option. And the majority
|
|
1605 of users, who can turn flow control off, were unwilling to switch to
|
|
1606 less mnemonic key bindings for the sake of flow control.
|
|
1607
|
|
1608 So which usage is ``right'', XEmacs's or that of some terminal and
|
|
1609 concentrator manufacturers? This question has no simple answer.
|
|
1610
|
|
1611 One reason why we are reluctant to cater to the problems caused by
|
|
1612 @kbd{C-s} and @kbd{C-q} is that they are gratuitous. There are other
|
|
1613 techniques (albeit less common in practice) for flow control that
|
|
1614 preserve transparency of the character stream. Note also that their use
|
|
1615 for flow control is not an official standard. Interestingly, on the
|
|
1616 model 33 teletype with a paper tape punch (which is very old), @kbd{C-s}
|
|
1617 and @kbd{C-q} were sent by the computer to turn the punch on and off!
|
|
1618
|
|
1619 As X servers and other window systems replace character-only
|
|
1620 terminals, this problem is gradually being cured. For the mean time,
|
|
1621 XEmacs provides a convenient way of enabling flow control if you want it:
|
|
1622 call the function @code{enable-flow-control}.
|
|
1623
|
444
|
1624 @deffn Command enable-flow-control &optional argument
|
428
|
1625 This function enables use of @kbd{C-s} and @kbd{C-q} for output flow
|
|
1626 control, and provides the characters @kbd{C-\} and @kbd{C-^} as aliases
|
|
1627 for them using @code{keyboard-translate-table} (@pxref{Translating Input}).
|
444
|
1628
|
|
1629 With optional argument @var{argument} (interactively the prefix
|
|
1630 argument), enable flow control mode if @var{argument} is positive; else
|
|
1631 disable it.
|
|
1632 @end deffn
|
428
|
1633
|
|
1634 You can use the function @code{enable-flow-control-on} in your
|
|
1635 @file{.emacs} file to enable flow control automatically on certain
|
|
1636 terminal types.
|
|
1637
|
|
1638 @defun enable-flow-control-on &rest termtypes
|
|
1639 This function enables flow control, and the aliases @kbd{C-\} and @kbd{C-^},
|
|
1640 if the terminal type is one of @var{termtypes}. For example:
|
|
1641
|
|
1642 @smallexample
|
|
1643 (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
|
|
1644 @end smallexample
|
|
1645 @end defun
|
|
1646
|
|
1647 Here is how @code{enable-flow-control} does its job:
|
|
1648
|
|
1649 @enumerate
|
|
1650 @item
|
|
1651 @cindex @sc{cbreak}
|
|
1652 It sets @sc{cbreak} mode for terminal input, and tells the operating
|
|
1653 system to handle flow control, with @code{(set-input-mode nil t)}.
|
|
1654
|
|
1655 @item
|
|
1656 It sets up @code{keyboard-translate-table} to translate @kbd{C-\} and
|
|
1657 @kbd{C-^} into @kbd{C-s} and @kbd{C-q}. Except at its very
|
|
1658 lowest level, XEmacs never knows that the characters typed were anything
|
|
1659 but @kbd{C-s} and @kbd{C-q}, so you can in effect type them as @kbd{C-\}
|
|
1660 and @kbd{C-^} even when they are input for other commands.
|
|
1661 @xref{Translating Input}.
|
|
1662 @end enumerate
|
|
1663
|
|
1664 If the terminal is the source of the flow control characters, then once
|
|
1665 you enable kernel flow control handling, you probably can make do with
|
|
1666 less padding than normal for that terminal. You can reduce the amount
|
|
1667 of padding by customizing the Termcap entry. You can also reduce it by
|
|
1668 setting @code{baud-rate} to a smaller value so that XEmacs uses a smaller
|
|
1669 speed when calculating the padding needed. @xref{Terminal Output}.
|
|
1670
|
|
1671 @node Batch Mode
|
|
1672 @section Batch Mode
|
|
1673 @cindex batch mode
|
|
1674 @cindex noninteractive use
|
|
1675
|
|
1676 The command line option @samp{-batch} causes XEmacs to run
|
|
1677 noninteractively. In this mode, XEmacs does not read commands from the
|
|
1678 terminal, it does not alter the terminal modes, and it does not expect
|
|
1679 to be outputting to an erasable screen. The idea is that you specify
|
|
1680 Lisp programs to run; when they are finished, XEmacs should exit. The
|
|
1681 way to specify the programs to run is with @samp{-l @var{file}}, which
|
|
1682 loads the library named @var{file}, and @samp{-f @var{function}}, which
|
|
1683 calls @var{function} with no arguments.
|
|
1684
|
|
1685 Any Lisp program output that would normally go to the echo area,
|
|
1686 either using @code{message} or using @code{prin1}, etc., with @code{t}
|
|
1687 as the stream, goes instead to XEmacs's standard error descriptor when
|
|
1688 in batch mode. Thus, XEmacs behaves much like a noninteractive
|
|
1689 application program. (The echo area output that XEmacs itself normally
|
|
1690 generates, such as command echoing, is suppressed entirely.)
|
|
1691
|
|
1692 @defun noninteractive
|
|
1693 This function returns non-@code{nil} when XEmacs is running in batch mode.
|
|
1694 @end defun
|
|
1695
|
|
1696 @defvar noninteractive
|
|
1697 This variable is non-@code{nil} when XEmacs is running in batch mode.
|
|
1698 Setting this variable to @code{nil}, however, will not change whether
|
|
1699 XEmacs is running in batch mode, and will not change the return value
|
|
1700 of the @code{noninteractive} function.
|
|
1701 @end defvar
|