| '\" |
| '\" Copyright (c) 1990-1992 The Regents of the University of California. |
| '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" RCS: @(#) $Id: DoOneEvent.3,v 1.2 1998/09/14 18:39:48 stanton Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| '\" or "in/out" to describe whether procedure reads or modifies arg, |
| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
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| '\" .CS |
| '\" Begin code excerpt. |
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| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
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| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
| '\" |
| '\" .SE |
| '\" End of list of standard options for a Tk widget. |
| '\" |
| '\" .OP cmdName dbName dbClass |
| '\" Start of description of a specific option. cmdName gives the |
| '\" option's name as specified in the class command, dbName gives |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
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| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
| .\} |
| .ta \\n()Au \\n()Bu |
| .ie !"\\$3"" \{\ |
| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
| .\} |
| .el \{\ |
| .br |
| .ie !"\\$2"" \{\ |
| \&\\$1 \\fI\\$2\\fP |
| .\} |
| .el \{\ |
| \&\\fI\\$1\\fP |
| .\} |
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| .. |
| '\" # define tabbing values for .AP |
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| .nr )A 10n |
| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
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| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
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| .if n \l'\\n(.lu\(ul' |
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| .ie n \l'\\n(^lu\(ul' |
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| .ie !\\n(^b-1 \{\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
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| \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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| \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| .sp -1 |
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| .ev |
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| '\" # Special macro to handle page bottom: finish off current |
| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| '\" # page bottom macro. |
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| 'ti 0 |
| 'nf |
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| .if \\n(^b \{\ |
| .\" Draw three-sided box if this is the box's first page, |
| .\" draw two sides but no top otherwise. |
| .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 |
| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
| .if \\n(^v \{\ |
| .nr ^x \\n(^tu+1v-\\n(^Yu |
| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
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| .ev |
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| .if \\n(^v \{\ |
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| .. |
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| .de DE |
| .fi |
| .RE |
| .sp |
| .. |
| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
| .de CS |
| .RS |
| .nf |
| .ta .25i .5i .75i 1i |
| .. |
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| .de CE |
| .fi |
| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH Tcl_DoOneEvent 3 7.5 Tcl "Tcl Library Procedures" |
| .BS |
| .SH NAME |
| Tcl_DoOneEvent \- wait for events and invoke event handlers |
| .SH SYNOPSIS |
| .nf |
| \fB#include <tcl.h>\fR |
| .sp |
| int |
| \fBTcl_DoOneEvent\fR(\fIflags\fR) |
| .SH ARGUMENTS |
| .AS int flags |
| .AP int flags in |
| This parameter is normally zero. It may be an OR-ed combination |
| of any of the following flag bits: |
| TCL_WINDOW_EVENTS, |
| TCL_FILE_EVENTS, TCL_TIMER_EVENTS, TCL_IDLE_EVENTS, TCL_ALL_EVENTS, or |
| TCL_DONT_WAIT. |
| .BE |
| |
| .SH DESCRIPTION |
| .PP |
| This procedure is the entry point to Tcl's event loop; it is responsible for |
| waiting for events and dispatching event handlers created with |
| procedures such as \fBTk_CreateEventHandler\fR, \fBTcl_CreateFileHandler\fR, |
| \fBTcl_CreateTimerHandler\fR, and \fBTcl_DoWhenIdle\fR. |
| \fBTcl_DoOneEvent\fR checks to see if |
| events are already present on the Tcl event queue; if so, |
| it calls the handler(s) for the first (oldest) event, removes it from |
| the queue, and returns. |
| If there are no events ready to be handled, then \fBTcl_DoOneEvent\fR |
| checks for new events from all possible sources. |
| If any are found, it puts all of them on Tcl's event queue, calls |
| handlers for the first event on the queue, and returns. |
| If no events are found, \fBTcl_DoOneEvent\fR checks for \fBTcl_DoWhenIdle\fR |
| callbacks; if any are found, it invokes all of them and returns. |
| Finally, if no events or idle callbacks have been found, then |
| \fBTcl_DoOneEvent\fR sleeps until an event occurs; then it adds any |
| new events to the Tcl event queue, calls handlers for the first event, |
| and returns. |
| The normal return value is 1 to signify that some event |
| was processed (see below for other alternatives). |
| .PP |
| If the \fIflags\fR argument to \fBTcl_DoOneEvent\fR is non-zero, |
| it restricts the kinds of events that will be processed by |
| \fBTcl_DoOneEvent\fR. |
| \fIFlags\fR may be an OR-ed combination of any of the following bits: |
| .TP 27 |
| \fBTCL_WINDOW_EVENTS\fR \- |
| Process window system events. |
| .TP 27 |
| \fBTCL_FILE_EVENTS\fR \- |
| Process file events. |
| .TP 27 |
| \fBTCL_TIMER_EVENTS\fR \- |
| Process timer events. |
| .TP 27 |
| \fBTCL_IDLE_EVENTS\fR \- |
| Process idle callbacks. |
| .TP 27 |
| \fBTCL_ALL_EVENTS\fR \- |
| Process all kinds of events: equivalent to OR-ing together all of the |
| above flags or specifying none of them. |
| .TP 27 |
| \fBTCL_DONT_WAIT\fR \- |
| Don't sleep: process only events that are ready at the time of the |
| call. |
| .LP |
| If any of the flags \fBTCL_WINDOW_EVENTS\fR, \fBTCL_FILE_EVENTS\fR, |
| \fBTCL_TIMER_EVENTS\fR, or \fBTCL_IDLE_EVENTS\fR is set, then the only |
| events that will be considered are those for which flags are set. |
| Setting none of these flags is equivalent to the value |
| \fBTCL_ALL_EVENTS\fR, which causes all event types to be processed. |
| If an application has defined additional event sources with |
| \fBTcl_CreateEventSource\fR, then additional \fIflag\fR values |
| may also be valid, depending on those event sources. |
| .PP |
| The \fBTCL_DONT_WAIT\fR flag causes \fBTcl_DoOneEvent\fR not to put |
| the process to sleep: it will check for events but if none are found |
| then it returns immediately with a return value of 0 to indicate |
| that no work was done. |
| \fBTcl_DoOneEvent\fR will also return 0 without doing anything if |
| the only alternative is to block forever (this can happen, for example, |
| if \fIflags\fR is \fBTCL_IDLE_EVENTS\fR and there are no |
| \fBTcl_DoWhenIdle\fR callbacks pending, or if no event handlers or |
| timer handlers exist). |
| .PP |
| \fBTcl_DoOneEvent\fR may be invoked recursively. For example, |
| it is possible to invoke \fBTcl_DoOneEvent\fR recursively |
| from a handler called by \fBTcl_DoOneEvent\fR. This sort |
| of operation is useful in some modal situations, such |
| as when a |
| notification dialog has been popped up and an application wishes to |
| wait for the user to click a button in the dialog before |
| doing anything else. |
| |
| .SH KEYWORDS |
| callback, event, handler, idle, timer |