Tcl_CreateTimerHandlerTcl Library ProcedTcl_CreateTimerHandler(3)_________________________________________________________________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 mil-
liseconds 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 previ-
ously-created
timer handler
(the return
value from some
previous call to
Tcl_CreateTimer-
Handler).
_________________________________________________________________DESCRIPTION
Tcl_CreateTimerHandler arranges for proc to be invoked at
a time milliseconds milliseconds in the future. The call-
back to proc will be made by Tcl_DoOneEvent, so Tcl_Cre-
ateTimerHandler 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.
Tcl 7.5 1
Tcl_CreateTimerHandlerTcl Library ProcedTcl_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 client-
Data argument given to Tcl_CreateTimerHandler when the
callback was created. Typically, clientData points to a
data structure containing application-specific information
about what to do in proc.
Tcl_DeleteTimerHandler may be called to delete a previ-
ously-created timer handler. It deletes the handler indi-
cated 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 pro-
cedure does nothing.
KEYWORDS
callback, clock, handler, timer
Tcl 7.5 2
