1Tcl_CreateTimerHandler(3) Tcl Library Procedures Tcl_CreateTimerHandler(3)
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6
8 Tcl_CreateTimerHandler, Tcl_DeleteTimerHandler - call a procedure at a
9 given time
10
12 #include <tcl.h>
13 Tcl_TimerToken
15 Tcl_CreateTimerHandler(milliseconds, proc, clientData)
16 Tcl_DeleteTimerHandler(token)
18
20 int milliseconds (in) How many milliseconds to wait
21 before invoking proc.
22 Tcl_TimerProc *proc (in) Procedure to invoke after
24 milliseconds have elapsed.
25 ClientData clientData (in) Arbitrary one-word value to
27 pass to proc.
28 Tcl_TimerToken token (in) Token for previously-created
30 timer handler (the return
31 value from some previous call
32 to Tcl_CreateTimerHandler).
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34
37 Tcl_CreateTimerHandler arranges for proc to be invoked at a time mil‐
38 liseconds milliseconds in the future. The callback to proc will be
39 made by Tcl_DoOneEvent, so Tcl_CreateTimerHandler is only useful in
40 programs that dispatch events through Tcl_DoOneEvent or through Tcl
41 commands such as vwait. The call to proc may not be made at the exact
42 time given by milliseconds: it will be made at the next opportunity
43 after that time. For example, if Tcl_DoOneEvent isn't called until
44 long after the time has elapsed, or if there are other pending events
45 to process before the call to proc, then the call to proc will be
46 delayed.
47 Proc should have arguments and return value that match the type
49 Tcl_TimerProc:
50 typedef void Tcl_TimerProc(ClientData clientData);
51 The clientData parameter to proc is a copy of the clientData argument
52 given to Tcl_CreateTimerHandler when the callback was created. Typi‐
53 cally, clientData points to a data structure containing application-
54 specific information about what to do in proc.
55 Tcl_DeleteTimerHandler may be called to delete a previously-created
57 timer handler. It deletes the handler indicated by token so that no
58 call to proc will be made; if that handler no longer exists (e.g.
59 because the time period has already elapsed and proc has been invoked
60 then Tcl_DeleteTimerHandler does nothing. The tokens returned by
61 Tcl_CreateTimerHandler never have a value of NULL, so if NULL is passed
62 to Tcl_DeleteTimerHandler then the procedure does nothing.
63
66 callback, clock, handler, timer
67Tcl 7.5 Tcl_CreateTimerHandler(3)