42 lines
2.1 KiB
HTML
42 lines
2.1 KiB
HTML
<HTML><HEAD><TITLE>Tk Built-In Commands - update manual page</TITLE></HEAD>
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<BR>
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<BODY bgcolor = #c3c3ff>
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<H2><IMG ALIGN=BOTTOM SRC="./Img/ManPageBlue.gif"> update</H2>
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<I>Process pending events and/or when-idle handlers</I><P><IMG ALIGN=TOP SRC="./Img/line-red.gif">
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<H3><A NAME="M2">SYNOPSIS</A></H3>
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(<B>update</B>)<BR>
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(<B>update</B> '<B>idletasks</B>)<BR>
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<H3><A NAME="M3">DESCRIPTION</A></H3>
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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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<P>
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If the <B>idletasks</B> 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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<P>
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The <B>update idletasks</B> 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 <B>update idletasks</B> 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 <B>update idletasks</B>.
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<P>
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The <B>update</B> 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 <B>update</B> then user input will be processed during the
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next call to <B>update</B>.
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<P><IMG ALIGN=TOP SRC="./Img/line-red.gif"><P>
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<A HREF=./STk-hlp.html><IMG ALIGN=BOTTOM SRC="./Img/RefBookBlue.gif"> Back to the <B>STk</B> main page</A>
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</BODY></HTML>
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