53 lines
2.1 KiB
Plaintext
53 lines
2.1 KiB
Plaintext
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'\"
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'\" Copyright (c) 1990-1992 The Regents of the University of California.
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'\" Copyright (c) 1994-1995 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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'\" @(#) update.n 1.9 95/05/20 16:34:48
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'\"
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.so STk-man.macros
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.TH update n 3.1 STk "Tk 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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update \- Process pending events and/or when-idle handlers
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.SH SYNOPSIS
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(\fBupdate\fR)
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.sp
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(\fBupdate\fR '\fBidletasks\fR)
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.BE
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.SH DESCRIPTION
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.PP
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This procedure is used to bring the entire application world
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``up to date.''
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It flushes all pending output to the display, waits for the
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server to process that output and return errors or events,
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handles all pending events of any sort (including when-idle handlers),
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and repeats this set of operations until there are no pending
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events, no pending when-idle handlers, no pending output to the server,
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and no operations still outstanding at the server.
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.PP
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If the \fBidletasks\fR option is specified as an argument to the
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procedure, then no new events or errors are processed; only when-idle
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idlers are invoked.
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This causes operations that are normally deferred, such as display
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updates and window layout calculations, to be performed immediately.
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.PP
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The \fBupdate idletasks\fR procedure is useful in scripts where
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changes have been made to the application's state and you want those
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changes to appear on the display immediately, rather than waiting
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for the script to complete. Most display updates are performed as
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idle handlers, so \fBupdate idletasks\fR will cause them to run.
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However, there are some kinds of updates that only happen in
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response to events, such as those triggered by window size changes;
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these updates will not occur in \fBupdate idletasks\fR.
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.PP
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The \fBupdate\fR procedure with no options is useful in scripts where
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you are performing a long-running computation but you still want
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the application to respond to user interactions; if you occasionally
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call \fBupdate\fR then user input will be processed during the
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next call to \fBupdate\fR.
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