2 '\" Copyright (c) 1990 The Regents of the University of California.
3 '\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
5 '\" See the file "license.terms" for information on usage and redistribution
6 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
8 .TH Tcl_DoWhenIdle 3 7.5 Tcl "Tcl Library Procedures"
9 .\" The -*- nroff -*- definitions below are for supplemental macros used
10 .\" in Tcl/Tk manual entries.
12 .\" .AP type name in/out ?indent?
13 .\" Start paragraph describing an argument to a library procedure.
14 .\" type is type of argument (int, etc.), in/out is either "in", "out",
15 .\" or "in/out" to describe whether procedure reads or modifies arg,
16 .\" and indent is equivalent to second arg of .IP (shouldn't ever be
17 .\" needed; use .AS below instead)
20 .\" Give maximum sizes of arguments for setting tab stops. Type and
21 .\" name are examples of largest possible arguments that will be passed
22 .\" to .AP later. If args are omitted, default tab stops are used.
25 .\" Start box enclosure. From here until next .BE, everything will be
26 .\" enclosed in one large box.
29 .\" End of box enclosure.
32 .\" Begin code excerpt.
37 .\" .VS ?version? ?br?
38 .\" Begin vertical sidebar, for use in marking newly-changed parts
39 .\" of man pages. The first argument is ignored and used for recording
40 .\" the version when the .VS was added, so that the sidebars can be
41 .\" found and removed when they reach a certain age. If another argument
42 .\" is present, then a line break is forced before starting the sidebar.
45 .\" End of vertical sidebar.
48 .\" Begin an indented unfilled display.
51 .\" End of indented unfilled display.
54 .\" Start of list of standard options for a Tk widget. The manpage
55 .\" argument defines where to look up the standard options; if
56 .\" omitted, defaults to "options". The options follow on successive
57 .\" lines, in three columns separated by tabs.
60 .\" End of list of standard options for a Tk widget.
62 .\" .OP cmdName dbName dbClass
63 .\" Start of description of a specific option. cmdName gives the
64 .\" option's name as specified in the class command, dbName gives
65 .\" the option's name in the option database, and dbClass gives
66 .\" the option's class in the option database.
69 .\" Print arg1 underlined, then print arg2 normally.
72 .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
75 .\" Print an open parenthesis, arg1 in quotes, then arg2 normally
76 .\" (for trailing punctuation) and then a closing parenthesis.
78 .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
82 .\" # Start an argument description
86 . ie !"\\$2"" .TP \\n()Cu
91 \&\\$1 \\fI\\$2\\fP (\\$3)
104 .\" # define tabbing values for .AP
107 .if !"\\$1"" .nr )A \\w'\\$1'u+3n
110 .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n
111 .nr )C \\n()Bu+\\w'(in/out)'u+2n
113 .AS Tcl_Interp Tcl_CreateInterp in/out
114 .\" # BS - start boxed text
115 .\" # ^y = starting y location
123 .if n \l'\\n(.lu\(ul'
126 .\" # BE - end boxed text (draw box now)
131 .ie n \l'\\n(^lu\(ul'
133 .\" Draw four-sided box normally, but don't draw top of
134 .\" box if the box started on an earlier page.
136 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
139 \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
146 .\" # VS - start vertical sidebar
147 .\" # ^Y = starting y location
148 .\" # ^v = 1 (for troff; for nroff this doesn't matter)
152 .ie n 'mc \s12\(br\s0
155 .\" # VE - end of vertical sidebar
163 \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n'
170 .\" # Special macro to handle page bottom: finish off current
171 .\" # box/sidebar if in box/sidebar mode, then invoked standard
172 .\" # page bottom macro.
179 .\" Draw three-sided box if this is the box's first page,
180 .\" draw two sides but no top otherwise.
181 .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
182 .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
185 .nr ^x \\n(^tu+1v-\\n(^Yu
186 \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c
199 .\" # DS - begin display
205 .\" # DE - end display
211 .\" # SO - start of list of standard options
213 'ie '\\$1'' .ds So \\fBoptions\\fR
214 'el .ds So \\fB\\$1\\fR
215 .SH "STANDARD OPTIONS"
221 .\" # SE - end of list of standard options
226 See the \\*(So manual entry for details on the standard options.
228 .\" # OP - start of full description for a single option
233 Command-Line Name: \\fB\\$1\\fR
234 Database Name: \\fB\\$2\\fR
235 Database Class: \\fB\\$3\\fR
239 .\" # CS - begin code excerpt
245 .\" # CE - end code excerpt
250 .\" # UL - underline word
254 .\" # QW - apply quotation marks to word
256 .ie '\\*(lq'"' ``\\$1''\\$2
257 .\"" fix emacs highlighting
258 .el \\*(lq\\$1\\*(rq\\$2
260 .\" # PQ - apply parens and quotation marks to word
262 .ie '\\*(lq'"' (``\\$1''\\$2)\\$3
263 .\"" fix emacs highlighting
264 .el (\\*(lq\\$1\\*(rq\\$2)\\$3
266 .\" # QR - quoted range
268 .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
269 .\"" fix emacs highlighting
270 .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
272 .\" # MT - "empty" string
278 Tcl_DoWhenIdle, Tcl_CancelIdleCall \- invoke a procedure when there are no pending events
281 \fB#include <tcl.h>\fR
283 \fBTcl_DoWhenIdle\fR(\fIproc, clientData\fR)
285 \fBTcl_CancelIdleCall\fR(\fIproc, clientData\fR)
287 .AS Tcl_IdleProc clientData
288 .AP Tcl_IdleProc *proc in
290 .AP ClientData clientData in
291 Arbitrary one-word value to pass to \fIproc\fR.
295 \fBTcl_DoWhenIdle\fR arranges for \fIproc\fR to be invoked
296 when the application becomes idle. The application is
297 considered to be idle when \fBTcl_DoOneEvent\fR has been
298 called, could not find any events to handle, and is about
299 to go to sleep waiting for an event to occur. At this
300 point all pending \fBTcl_DoWhenIdle\fR handlers are
301 invoked. For each call to \fBTcl_DoWhenIdle\fR there will
302 be a single call to \fIproc\fR; after \fIproc\fR is
303 invoked the handler is automatically removed.
304 \fBTcl_DoWhenIdle\fR is only usable in programs that
305 use \fBTcl_DoOneEvent\fR to dispatch events.
307 \fIProc\fR should have arguments and result that match the
308 type \fBTcl_IdleProc\fR:
311 typedef void \fBTcl_IdleProc\fR(
312 ClientData \fIclientData\fR);
315 The \fIclientData\fR parameter to \fIproc\fR is a copy of the \fIclientData\fR
316 argument given to \fBTcl_DoWhenIdle\fR. Typically, \fIclientData\fR
317 points to a data structure containing application-specific information about
318 what \fIproc\fR should do.
320 \fBTcl_CancelIdleCall\fR
321 may be used to cancel one or more previous
322 calls to \fBTcl_DoWhenIdle\fR: if there is a \fBTcl_DoWhenIdle\fR
323 handler registered for \fIproc\fR and \fIclientData\fR, then it
324 is removed without invoking it. If there is more than one
325 handler on the idle list that refers to \fIproc\fR and \fIclientData\fR,
326 all of the handlers are removed. If no existing handlers match
327 \fIproc\fR and \fIclientData\fR then nothing happens.
329 \fBTcl_DoWhenIdle\fR is most useful in situations where
330 (a) a piece of work will have to be done but (b) it is
331 possible that something will happen in the near future
332 that will change what has to be done or require something
333 different to be done. \fBTcl_DoWhenIdle\fR allows the
334 actual work to be deferred until all pending events have
335 been processed. At this point the exact work to be done
336 will presumably be known and it can be done exactly once.
338 For example, \fBTcl_DoWhenIdle\fR might be used by an editor
339 to defer display updates until all pending commands have
340 been processed. Without this feature, redundant redisplays
341 might occur in some situations, such as the processing of
345 At present it is not safe for an idle callback to reschedule itself
346 continuously. This will interact badly with certain features of Tk
347 that attempt to wait for all idle callbacks to complete. If you would
348 like for an idle callback to reschedule itself continuously, it is
349 better to use a timer handler with a zero timeout period.
351 after(n), Tcl_CreateFileHandler(3), Tcl_CreateTimerHandler(3)
353 callback, defer, idle callback