Tcl_CreateTimerHandler(3tcl)

Tcl_CreateTimerHandler(3Tcl Library ProcedureTcl_CreateTimerHandler(3)

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NAME

     Tcl_CreateTimerHandler, Tcl_DeleteTimerHandler - call a pro-
     cedure at a given time

SYNOPSIS

     #include <tcl.h>

     Tcl_TimerToken
     Tcl_CreateTimerHandler(milliseconds, proc, clientData)

     Tcl_DeleteTimerHandler(token)

ARGUMENTS

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

     Tcl_TimerProc *proc (in)                  Procedure       to
                                               invoke  after mil-
                                               liseconds     have
                                               elapsed.

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

     Tcl_TimerToken token (in)                 Token  for  previ-
                                               ously      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  useful  in  programs  that
     dispatch events through Tcl_DoOneEvent or through  Tcl  com-
     mands  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.

Tcl                     Last change: 7.5                        1

Tcl_CreateTimerHandler(3Tcl Library ProcedureTcl_CreateTimerHandler(3)

     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  struc-
     ture  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                     Last change: 7.5                        2