Tcl_CreateTimerHandler(3)				      Tcl Library Procedures					 Tcl_CreateTimerHandler(3)

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NAME

       Tcl_CreateTimerHandler, Tcl_DeleteTimerHandler - call a procedure at a given time

SYNOPSIS

       #include <tcl.h>

       Tcl_TimerToken
       Tcl_CreateTimerHandler(milliseconds, proc, clientData)

       Tcl_DeleteTimerHandler(token)

ARGUMENTS

       int		milliseconds   (in)	 How many milliseconds to wait before invoking proc.

       Tcl_TimerProc	*proc	       (in)	 Procedure to invoke after milliseconds have elapsed.

       ClientData	clientData     (in)	 Arbitrary one-word value to pass to proc.

       Tcl_TimerToken	token	       (in)	 Token	for previously-created timer handler (the return value from some previous call to Tcl_Cre-
						 ateTimerHandler).
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DESCRIPTION

       Tcl_CreateTimerHandler arranges for proc to be invoked at a time milliseconds milliseconds in the future.  The callback	to  proc  will	be
       made  by  Tcl_DoOneEvent,  so  Tcl_CreateTimerHandler is only useful in programs that dispatch events through Tcl_DoOneEvent or through Tcl
       commands such as vwait.	The call to proc may not be made at the exact time given by milliseconds:  it will be made at the next opportunity
       after  that  time.  For example, if Tcl_DoOneEvent isn't called until long after the time has elapsed, or if there are other pending events
       to process before the call to proc, then the call to proc will be delayed.

       Proc should have arguments and return value that match the type Tcl_TimerProc:
	      typedef void Tcl_TimerProc(ClientData clientData);
       The clientData parameter to proc is a copy of the clientData argument given to Tcl_CreateTimerHandler when the callback was created.  Typi-
       cally, clientData points to a data structure containing application-specific information about what to do in proc.

       Tcl_DeleteTimerHandler  may  be	called to delete a previously-created timer handler.  It deletes the handler indicated by token so that no
       call to proc will be made;  if that handler no longer exists (e.g. because the time period has already elapsed and proc	has  been  invoked
       then  Tcl_DeleteTimerHandler  does nothing.  The tokens returned by Tcl_CreateTimerHandler never have a value of NULL, so if NULL is passed
       to Tcl_DeleteTimerHandler then the procedure does nothing.

KEYWORDS

       callback, clock, handler, timer

Tcl									7.5						 Tcl_CreateTimerHandler(3)