Tk_CreateTimerHandler(3Tk)Tk_CreateTimerHandler(3Tk)NAME
Tk_CreateTimerHandler, Tk_DeleteTimerHandler - call a procedure at a
given time
SYNOPSIS
#include <tk.h>
Tk_TimerToken
Tk_CreateTimerHandler(milliseconds, proc, clientData)
Tk_DeleteTimerHandler(token)ARGUMENTS
int milliseconds (in) How many milliseconds to wait
before invoking proc.
Tk_TimerProc *proc (in) Procedure to invoke after
milliseconds have elapsed.
ClientData clientData (in) Arbitrary one-word value to pass
to proc.
Tk_TimerToken token (in) Token for previously-created
timer handler (the return value
from some previous call to
Tk_CreateTimerHandler).
DESCRIPTIONTk_CreateTimerHandler arranges for proc to be invoked at a time
milliseconds milliseconds in the future. The callback to proc will be
made by Tk_DoOneEvent, so Tk_CreateTimerHandler is only useful in
programs that dispatch events through Tk_DoOneEvent or through other Tk
procedures that call Tk_DoOneEvent, such as Tk_MainLoop. 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
Tk_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
Tk_TimerProc:
typedef void Tk_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 application-
specific information about what to do in proc.
Tk_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
Page 1
Tk_CreateTimerHandler(3Tk)Tk_CreateTimerHandler(3Tk)
Tk_DeleteTimerHandler does nothing.
KEYWORDS
callback, clock, handler, timer
Page 2
