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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_CreateTimerHandler).
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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 use-ful useful
       ful 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 is not 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.  Typically, clientData points to a data structure containing applica-tion-specific application-specific
       tion-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_DeleteTimerHan-dler Tcl_DeleteTimerHandler
       dler  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)