33 lines
1.7 KiB
HTML
33 lines
1.7 KiB
HTML
<HTML><HEAD><TITLE>Tcl Built-In Commands - vwait manual page</TITLE></HEAD><BODY>
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<H3><A NAME="M2">NAME</A></H3>
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vwait - Process events until a variable is written
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<H3><A NAME="M3">SYNOPSIS</A></H3>
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<B>vwait</B> <I>varName</I><BR>
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<H3><A NAME="M4">DESCRIPTION</A></H3>
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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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<I>varName</I>. Once <I>varName</I> has been set, the <B>vwait</B>
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command will return as soon as the event handler that modified
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<I>varName</I> completes. <I>varName</I> must globally scoped
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(either with a call to <B><A HREF="../TkCmd/global.htm">global</A></B> for the <I>varName</I>, or with
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the full namespace path specification).
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<P>
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In some cases the <B>vwait</B> command may not return immediately
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after <I>varName</I> is set. This can happen if the event handler
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that sets <I>varName</I> does not complete immediately. For example,
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if an event handler sets <I>varName</I> and then itself calls
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<B>vwait</B> 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 <B>vwait</B> 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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<H3><A NAME="M5">SEE ALSO</A></H3>
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<B><A HREF="../TkCmd/global.htm">global</A></B>
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<H3><A NAME="M6">KEYWORDS</A></H3>
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<A href="../Keywords/E.htm#event">event</A>, <A href="../Keywords/V.htm#variable">variable</A>, <A href="../Keywords/W.htm#wait">wait</A>
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<HR><PRE>
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<A HREF="../copyright.htm">Copyright</A> © 1995-1996 Sun Microsystems, Inc.
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<A HREF="../copyright.htm">Copyright</A> © 1995-1997 Roger E. Critchlow Jr.</PRE>
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</BODY></HTML>
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