CancelWaitableTimer

The CancelWaitableTimer function sets the specified waitable timer to the inactive state.

BOOL CancelWaitableTimer(
  HANDLE hTimer  // handle to timer
);

Parameters

hTimer

[in] Handle to the timer object. The CreateWaitableTimer or OpenWaitableTimer function returns this handle.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The CancelWaitableTimer function does not change the signaled state of the timer. It stops the timer before it can be set to the signaled state and cancels outstanding APCs. Therefore, threads performing a wait operation on the timer remain waiting until they time out or the timer is reactivated and its state is set to signaled. If the timer is already in the signaled state, it remains in that state.

To reactivate the timer, call the SetWaitableTimer function.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Windows 95/98: Requires Windows 98.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.

See Also

Synchronization Overview, Synchronization Functions, CreateWaitableTimer, OpenWaitableTimer, SetWaitableTimer