SetTimer

The SetTimer function creates a timer with the specified time-out value.

UINT SetTimer(
  HWND hWnd,              // handle of window for timer messages
  UINT nIDEvent,          // timer identifier
  UINT uElapse,           // time-out value
  TIMERPROC lpTimerFunc   // address of timer procedure
);
 

Parameters

hWnd

Handle to the window to be associated with the timer. This window must be owned by the calling thread. If this parameter is NULL, no window is associated with the timer and the nIDEvent parameter is ignored.

nIDEvent

Specifies a nonzero timer identifier. If the hWnd parameter is NULL, this parameter is ignored.

uElapse

Specifies the time-out value, in milliseconds.

lpTimerFunc

Pointer to the function to be notified when the time-out value elapses. For more information about the function, see TimerProc.

If lpTimerFunc is NULL, the system posts a WM_TIMER message to the application queue. The hwnd member of the message's MSG structure contains the value of the hWnd parameter.

Return Values

If the function succeeds, the return value is an integer identifying the new timer. An application can pass this value, or the string identifier, if it exists, to the KillTimer function to destroy the timer.

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

Remarks

An application can process WM_TIMER messages by including a WM_TIMER case statement in the window procedure or by specifying a TimerProc callback function when creating the timer. When you specify a TimerProc callback function, the default window procedure calls the callback function when it processes WM_TIMER. Therefore, you need to dispatch messages in the calling thread, even when you use TimerProc instead of processing WM_TIMER.

The wParam parameter of the WM_TIMER message contains the value of the nIDEvent parameter.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winuser.h.
  Import Library: Use user32.lib.

See Also

Timers Overview, Timer Functions, KillTimer, MSG, TimerProc, WM_TIMER