49 lines
1.9 KiB
Plaintext
49 lines
1.9 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) 1994-1996 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: @(#) update.n 1.3 96/03/25 20:26:34
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'\"
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.so man.macros
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.TH update 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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update \- Process pending events and idle callbacks
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.SH SYNOPSIS
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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 command is used to bring the application ``up to date''
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by entering the event loop repeated until all pending events
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(including idle callbacks) have been processed.
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.PP
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If the \fBidletasks\fR keyword is specified as an argument to the
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command, then no new events or errors are processed; only idle
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callbacks 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 command 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 callbacks, 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 command 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 events such as user interactions; if
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you occasionally call \fBupdate\fR then user input will be processed
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during the next call to \fBupdate\fR.
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.SH KEYWORDS
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event, flush, handler, idle, update
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