83 lines
3.7 KiB
HTML
83 lines
3.7 KiB
HTML
<HTML><HEAD><TITLE>Tk Built-In Commands - after manual page</TITLE></HEAD>
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<BODY bgcolor = #c3c3ff>
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<H2><IMG ALIGN=BOTTOM SRC="./Img/ManPageBlue.gif"> after</H2>
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<I>Execute a command after a time delay</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>after </B><I>ms</I>)<BR>
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(<B>after </B><I>ms </I><I>thunk</I>)<BR>
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(<B>after 'cancel </B><I>id</I>)<BR>
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(<B>after 'cancel </B><I>thunk)</I><BR>
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(<B>after 'idle </B>?<I>thunk</I>?)<BR>
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(<B>after info</B>)<BR>
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(<B>after info </B><I>id</I>)<BR>
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<H3><A NAME="M3">DESCRIPTION</A></H3>
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The <B>after</B> procedure is used to delay execution of the program or to execute
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a procedure in background after a delay. It has several forms,
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depending on the first argument to the procedure:
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<P>
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<DL>
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<DT><A NAME="M4">(<B>after </B><I>ms</I>)</A><DD>
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<I>Ms</I> must be an integer giving a time in milliseconds.
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The procedure sleeps for <I>ms</I> milliseconds and then returns.
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While the procedure is sleeping the application does not respond to
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X events or any other events.
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<P>
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<DT><A NAME="M5">(<B>after </B><I>ms thunk</I>)</A><DD>
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In this form the procedure returns immediately, but it arranges
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for a STk procedure to be executed <I>ms</I> milliseconds later as a
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background event handler.
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The procedure will be executed exactly once, at the given time.
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The delayed procedure must be a <I>thunk</I>.
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If an error occurs while executing the delayed procedure then the
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<B>tkerror</B> mechanism is used to report the error.
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The <B>after</B> procedure returns a symbol that can be used
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to cancel the delayed procedure using <B>after cancel</B>.
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<P>
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<DT><A NAME="M6">(<B>after 'cancel </B><I>id</I>)</A><DD>
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Cancels the execution of a delayed procedure that
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was previously scheduled.
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<I>Id</I> indicates which procedure should be canceled; it must have
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been the return value from a previous <B>after</B> procedure.
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If the procedure given by <I>id</I> has already been executed then
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the <B>after cancel</B> procedure has no effect.
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<P>
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<DT><A NAME="M7">(<B>after 'cancel </B><I>thunk</I>)</A><DD>
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This procedure also cancels the execution of a delayed procedure. If there is
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a pending procedure that matches <I>thunk</I>, it is cancelled and will
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never be executed; if no such procedure is currently
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pending then the <B>after cancel</B> procedure has no effect.
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<P>
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<DT><A NAME="M8">(<B>after 'idle </B><I>thunk</I>)</A><DD>
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Arranges for the given <I>thunk</I> to be evaluated later as an idle handler
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The script will be run exactly once, the next time the Tk event
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loop is entered and there are no events to process.
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The procedure returns an identifier that can be used
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to cancel the delayed procedure using <B>after cancel</B>.
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If an error occurs while executing the script then the
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<B>tkerror</B> mechanism is used to report the error.
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<P>
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<DT><A NAME="M9">(<B>after 'info </B><I>id</I>)</A><DD>
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<DT><A NAME="M10">(<B>after 'info</B>)</A><DD>
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This procedure returns information about existing event handlers.
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If no <I>id</I> argument is supplied, then the procedure returns
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a list of the identifiers for all existing
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event handlers created by the <B>after</B> procedure for this
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interpreter.
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If <I>id</I> is supplied, it specifies an existing handler;
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<I>id</I> must have been the return value from some previous call
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to <B>after</B> and it must not have triggered yet or been cancelled.
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In this case the procedure returns a list with two elements.
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The first element of the list is the script associated
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with <I>id</I>, and the second element is either
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<B>idle</B> or <B>timer</B> to indicate what kind of event
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handler it is.
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<P>
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</DL>
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<H3><A NAME="M11">SEE ALSO</A></H3>
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<B>tkerror</B>
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<P><IMG ALIGN=TOP SRC="./Img/line-red.gif">
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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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