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 Tk_RestrictEvents 3 "" Tk "Tk 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
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37 .\" .VS ?version? ?br?
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39 .\" of man pages. The first argument is ignored and used for recording
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42 .\" is present, then a line break is forced before starting the sidebar.
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48 .\" Begin an indented unfilled display.
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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.
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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)
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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
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123 .if n \l'\\n(.lu\(ul'
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131 .ie n \l'\\n(^lu\(ul'
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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'
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163 \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n'
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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
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235 Database Class: \\fB\\$3\\fR
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256 .ie '\\*(lq'"' ``\\$1''\\$2
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258 .el \\*(lq\\$1\\*(rq\\$2
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262 .ie '\\*(lq'"' (``\\$1''\\$2)\\$3
263 .\"" fix emacs highlighting
264 .el (\\*(lq\\$1\\*(rq\\$2)\\$3
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268 .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
269 .\"" fix emacs highlighting
270 .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
272 .\" # MT - "empty" string
278 Tk_RestrictEvents \- filter and selectively delay X events
281 \fB#include <tk.h>\fR
284 \fBTk_RestrictEvents\fR(\fIproc, arg, prevArgPtr\fR)
286 .AS Tk_RestrictProc **prevArgPtr
287 .AP Tk_RestrictProc *proc in
288 Predicate procedure to call to filter incoming X events.
289 NULL means do not restrict events at all.
290 .AP ClientData arg in
291 Arbitrary argument to pass to \fIproc\fR.
292 .AP ClientData *prevArgPtr out
293 Pointer to place to save argument to previous restrict procedure.
297 This procedure is useful in certain situations where applications
298 are only prepared to receive certain X events. After
299 \fBTk_RestrictEvents\fR is called, \fBTk_DoOneEvent\fR (and
300 hence \fBTk_MainLoop\fR) will filter X input events through
301 \fIproc\fR. \fIProc\fR indicates whether a
302 given event is to be processed immediately, deferred until some
303 later time (e.g. when the event restriction is lifted), or discarded.
305 is a procedure with arguments and result that match
306 the type \fBTk_RestrictProc\fR:
308 typedef Tk_RestrictAction \fBTk_RestrictProc\fR(
309 ClientData \fIarg\fR,
310 XEvent *\fIeventPtr\fR);
312 The \fIarg\fR argument is a copy of the \fIarg\fR passed
313 to \fBTk_RestrictEvents\fR; it may be used to provide \fIproc\fR with
314 information it needs to filter events. The \fIeventPtr\fR points to
315 an event under consideration. \fIProc\fR returns a restrict action
316 (enumerated type \fBTk_RestrictAction\fR) that indicates what
317 \fBTk_DoOneEvent\fR should do with the event. If the return value is
318 \fBTK_PROCESS_EVENT\fR, then the event will be handled immediately.
319 If the return value is \fBTK_DEFER_EVENT\fR, then the event will be
320 left on the event queue for later processing. If the return value is
321 \fBTK_DISCARD_EVENT\fR, then the event will be removed from the event
322 queue and discarded without being processed.
324 \fBTk_RestrictEvents\fR uses its return value and \fIprevArgPtr\fR
325 to return information about the current event restriction procedure
326 (a NULL return value means there are currently no restrictions).
327 These values may be used to restore the previous restriction state
328 when there is no longer any need for the current restriction.
330 There are very few places where \fBTk_RestrictEvents\fR is needed.
331 In most cases, the best way to restrict events is by changing the
332 bindings with the \fBbind\fR Tcl command or by calling
333 \fBTk_CreateEventHandler\fR and \fBTk_DeleteEventHandler\fR from C.
334 The main place where \fBTk_RestrictEvents\fR must be used is when
335 performing synchronous actions (for example, if you need to wait
336 for a particular event to occur on a particular window but you do not
337 want to invoke any handlers for any other events). The
339 solution in these situations is to call \fBXNextEvent\fR or
340 \fBXWindowEvent\fR, but these procedures cannot be used because
341 Tk keeps its own event queue that is separate from the X event
342 queue. Instead, call \fBTk_RestrictEvents\fR to set up a filter,
343 then call \fBTk_DoOneEvent\fR to retrieve the desired event(s).
345 delay, event, filter, restriction