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39 lines
1.3 KiB
Plaintext
39 lines
1.3 KiB
Plaintext
'\"
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'\" Copyright (c) 1995-1996 Sun Microsystems, Inc.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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'\" SCCS: @(#) vwait.n 1.3 96/03/25 20:27:21
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'\"
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.so man.macros
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.TH vwait n 7.5 Tcl "Tcl Built-In Commands"
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.BS
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'\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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vwait \- Process events until a variable is written
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.SH SYNOPSIS
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\fBvwait\fR ?\fIvarName\fR?
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.BE
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.SH DESCRIPTION
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.PP
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This command enters the Tcl event loop to process events, blocking
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the application if no events are ready. It continues processing
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events until some event handler sets the value of variable
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\fIvarName\fR. Once \fIvarName\fR has been set, the \fBvwait\fR
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command will return as soon as the event handler that modified
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\fIvarName\fR completes.
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.PP
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In some cases the \fBvwait\fR command may not return immediately
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after \fIvarName\fR is set. This can happen if the event handler
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that sets \fIvarName\fR does not complete immediately. For example,
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if an event handler sets \fIvarName\fR and then itself calls
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\fBvwait\fR to wait for a different variable, then it may not return
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for a long time. During this time the top-level \fBvwait\fR is
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blocked waiting for the event handler to complete, so it cannot
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return either.
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.SH KEYWORDS
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event, variable, wait
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