[OpenSPARC-T2-SAM] / sam-t2 / devtools / v8plus / man / man3 / Tk_RestrictEvents.3

'\"
'\" Copyright (c) 1990 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\" RCS: @(#) $Id: RestrictEv.3,v 1.2 1998/09/14 18:22:53 stanton Exp $
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'\" The definitions below are for supplemental macros used in Tcl/Tk
'\" manual entries.
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'\"
'\" .OP cmdName dbName dbClass
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'\"	option's name as specified in the class command, dbName gives
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.TH Tk_RestrictEvents 3 "" Tk "Tk Library Procedures"
.BS
.SH NAME
Tk_RestrictEvents \- filter and selectively delay X events
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
Tk_RestrictProc *
\fBTk_RestrictEvents\fR(\fIproc, clientData, prevClientDataPtr\fR)
.SH ARGUMENTS
.AS Tk_RestrictProc **prevClientDataPtr
.AP Tk_RestrictProc *proc in
Predicate procedure to call to filter incoming X events.
NULL means do not restrict events at all.
.AP ClientData clientData in
Arbitrary argument to pass to \fIproc\fR.
.AP ClientData *prevClientDataPtr out
Pointer to place to save argument to previous restrict procedure.
.BE

.SH DESCRIPTION
.PP
This procedure is useful in certain situations where applications
are only prepared to receive certain X events.  After
\fBTk_RestrictEvents\fR is called, \fBTk_DoOneEvent\fR (and
hence \fBTk_MainLoop\fR) will filter X input events through
\fIproc\fR.  \fIProc\fR indicates whether a
given event is to be processed immediately, deferred until some
later time (e.g. when the event restriction is lifted), or discarded.
\fIProc\fR
is a procedure with arguments and result that match
the type \fBTk_RestrictProc\fR:
.CS
typedef Tk_RestrictAction Tk_RestrictProc(
	ClientData \fIclientData\fR,
	XEvent *\fIeventPtr\fR);
.CE
The \fIclientData\fR argument is a copy of the \fIclientData\fR passed
to \fBTk_RestrictEvents\fR; it may be used to provide \fIproc\fR with
information it needs to filter events.  The \fIeventPtr\fR points to
an event under consideration.  \fIProc\fR returns a restrict action
(enumerated type \fBTk_RestrictAction\fR) that indicates what
\fBTk_DoOneEvent\fR should do with the event.  If the return value is
\fBTK_PROCESS_EVENT\fR, then the event will be handled immediately.
If the return value is \fBTK_DEFER_EVENT\fR, then the event will be
left on the event queue for later processing.  If the return value is
\fBTK_DISCARD_EVENT\fR, then the event will be removed from the event
queue and discarded without being processed.
.PP
\fBTk_RestrictEvents\fR uses its return value and \fIprevClientDataPtr\fR
to return information about the current event restriction procedure
(a NULL return value means there are currently no restrictions).
These values may be used to restore the previous restriction state
when there is no longer any need for the current restriction.
.PP
There are very few places where \fBTk_RestrictEvents\fR is needed.
In most cases, the best way to restrict events is by changing the
bindings with the \fBbind\fR Tcl command or by calling
\fBTk_CreateEventHandler\fR and \fBTk_DeleteEventHandler\fR from C.
The main place where \fBTk_RestrictEvents\fR must be used is when
performing synchronous actions (for example, if you need to wait
for a particular event to occur on a particular window but you don't
want to invoke any handlers for any other events).  The ``obvious''
solution in these situations is to call \fBXNextEvent\fR or
\fBXWindowEvent\fR, but these procedures cannot be used because
Tk keeps its own event queue that is separate from the X event
queue.  Instead, call \fBTk_RestrictEvents\fR to set up a filter,
then call \fBTk_DoOneEvent\fR to retrieve the desired event(s).
.SH KEYWORDS
delay, event, filter, restriction
Commit	Line	Data
920dae64 AT	1	'\"
	2	'\" Copyright (c) 1990 The Regents of the University of California.
	3	'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
	4	'\"
	5	'\" See the file "license.terms" for information on usage and redistribution
	6	'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
	7	'\"
	8	'\" RCS: @(#) $Id: RestrictEv.3,v 1.2 1998/09/14 18:22:53 stanton Exp $
	9	'\"
	10	'\" The definitions below are for supplemental macros used in Tcl/Tk
	11	'\" manual entries.
	12	'\"
	13	'\" .AP type name in/out ?indent?
	14	'\" Start paragraph describing an argument to a library procedure.
	15	'\" type is type of argument (int, etc.), in/out is either "in", "out",
	16	'\" or "in/out" to describe whether procedure reads or modifies arg,
	17	'\" and indent is equivalent to second arg of .IP (shouldn't ever be
	18	'\" needed; use .AS below instead)
	19	'\"
	20	'\" .AS ?type? ?name?
	21	'\" Give maximum sizes of arguments for setting tab stops. Type and
	22	'\" name are examples of largest possible arguments that will be passed
	23	'\" to .AP later. If args are omitted, default tab stops are used.
	24	'\"
	25	'\" .BS
	26	'\" Start box enclosure. From here until next .BE, everything will be
	27	'\" enclosed in one large box.
	28	'\"
	29	'\" .BE
	30	'\" End of box enclosure.
	31	'\"
	32	'\" .CS
	33	'\" Begin code excerpt.
	34	'\"
	35	'\" .CE
	36	'\" End code excerpt.
	37	'\"
	38	'\" .VS ?version? ?br?
	39	'\" Begin vertical sidebar, for use in marking newly-changed parts
	40	'\" of man pages. The first argument is ignored and used for recording
	41	'\" the version when the .VS was added, so that the sidebars can be
	42	'\" found and removed when they reach a certain age. If another argument
	43	'\" is present, then a line break is forced before starting the sidebar.
	44	'\"
	45	'\" .VE
	46	'\" End of vertical sidebar.
	47	'\"
	48	'\" .DS
	49	'\" Begin an indented unfilled display.
	50	'\"
	51	'\" .DE
	52	'\" End of indented unfilled display.
	53	'\"
	54	'\" .SO
	55	'\" Start of list of standard options for a Tk widget. The
	56	'\" options follow on successive lines, in four columns separated
	57	'\" by tabs.
	58	'\"
	59	'\" .SE
	60	'\" End of list of standard options for a Tk widget.
	61	'\"
	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.
67	'\"
68	'\" .UL arg1 arg2
69	'\" Print arg1 underlined, then print arg2 normally.
70	'\"
71	'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
72	'\"
73	'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
74	.if t .wh -1.3i ^B
75	.nr ^l \n(.l
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79	.ie !"\\$4"" .TP \\$4
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81	. ie !"\\$2"" .TP \\n()Cu
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107	..
108	.AS Tcl_Interp Tcl_CreateInterp in/out
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134	\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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177	.el \h'-1.5n'\L'\|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'\|0u'\c
178	.\}
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181	\kx\h'-\\nxu'\h'\|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'\|0u'\c
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207	.de SO
208	.SH "STANDARD OPTIONS"
209	.LP
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213	..
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219	See the \\fBoptions\\fR manual entry for details on the standard options.
220	..
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222	.de OP
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226	Command-Line Name: \\fB\\$1\\fR
227	Database Name: \\fB\\$2\\fR
228	Database Class: \\fB\\$3\\fR
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243	.de UL
244	\\$1\l'\|0\(ul'\\$2
245	..
246	.TH Tk_RestrictEvents 3 "" Tk "Tk Library Procedures"
247	.BS
248	.SH NAME
249	Tk_RestrictEvents \- filter and selectively delay X events
250	.SH SYNOPSIS
251	.nf
252	\fB#include <tk.h>\fR
253	.sp
254	Tk_RestrictProc *
255	\fBTk_RestrictEvents\fR(\fIproc, clientData, prevClientDataPtr\fR)
256	.SH ARGUMENTS
257	.AS Tk_RestrictProc **prevClientDataPtr
258	.AP Tk_RestrictProc *proc in
259	Predicate procedure to call to filter incoming X events.
260	NULL means do not restrict events at all.
261	.AP ClientData clientData in
262	Arbitrary argument to pass to \fIproc\fR.
263	.AP ClientData *prevClientDataPtr out
264	Pointer to place to save argument to previous restrict procedure.
265	.BE
266
267	.SH DESCRIPTION
268	.PP
269	This procedure is useful in certain situations where applications
270	are only prepared to receive certain X events. After
271	\fBTk_RestrictEvents\fR is called, \fBTk_DoOneEvent\fR (and
272	hence \fBTk_MainLoop\fR) will filter X input events through
273	\fIproc\fR. \fIProc\fR indicates whether a
274	given event is to be processed immediately, deferred until some
275	later time (e.g. when the event restriction is lifted), or discarded.
276	\fIProc\fR
277	is a procedure with arguments and result that match
278	the type \fBTk_RestrictProc\fR:
279	.CS
280	typedef Tk_RestrictAction Tk_RestrictProc(
281	ClientData \fIclientData\fR,
282	XEvent *\fIeventPtr\fR);
283	.CE
284	The \fIclientData\fR argument is a copy of the \fIclientData\fR passed
285	to \fBTk_RestrictEvents\fR; it may be used to provide \fIproc\fR with
286	information it needs to filter events. The \fIeventPtr\fR points to
287	an event under consideration. \fIProc\fR returns a restrict action
288	(enumerated type \fBTk_RestrictAction\fR) that indicates what
289	\fBTk_DoOneEvent\fR should do with the event. If the return value is
290	\fBTK_PROCESS_EVENT\fR, then the event will be handled immediately.
291	If the return value is \fBTK_DEFER_EVENT\fR, then the event will be
292	left on the event queue for later processing. If the return value is
293	\fBTK_DISCARD_EVENT\fR, then the event will be removed from the event
294	queue and discarded without being processed.
295	.PP
296	\fBTk_RestrictEvents\fR uses its return value and \fIprevClientDataPtr\fR
297	to return information about the current event restriction procedure
298	(a NULL return value means there are currently no restrictions).
299	These values may be used to restore the previous restriction state
300	when there is no longer any need for the current restriction.
301	.PP
302	There are very few places where \fBTk_RestrictEvents\fR is needed.
303	In most cases, the best way to restrict events is by changing the
304	bindings with the \fBbind\fR Tcl command or by calling
305	\fBTk_CreateEventHandler\fR and \fBTk_DeleteEventHandler\fR from C.
306	The main place where \fBTk_RestrictEvents\fR must be used is when
307	performing synchronous actions (for example, if you need to wait
308	for a particular event to occur on a particular window but you don't
309	want to invoke any handlers for any other events). The ``obvious''
310	solution in these situations is to call \fBXNextEvent\fR or
311	\fBXWindowEvent\fR, but these procedures cannot be used because
312	Tk keeps its own event queue that is separate from the X event
313	queue. Instead, call \fBTk_RestrictEvents\fR to set up a filter,
314	then call \fBTk_DoOneEvent\fR to retrieve the desired event(s).
315	.SH KEYWORDS
316	delay, event, filter, restriction