UINT SetTimer( UINT nIDEvent, UINT nElapse, void (CALLBACK EXPORT* lpfnTimer)(HWND, UINT, UINT, DWORD) );
Return Value
The timer identifier of the new timer if the function is successful. An application passes this value to the KillTimer member function to kill the timer. Nonzero if successful; otherwise 0.
Parameters
nIDEvent
Specifies a nonzero timer identifier.
nElapse
Specifies the time-out value, in milliseconds.
lpfnTimer
Specifies the address of the application-supplied TimerProc callback function that processes the WM_TIMER messages. If this parameter is NULL, the WM_TIMER messages are placed in the application’s message queue and handled by the CWnd object.
Remarks
Installs a system timer. A time-out value is specified, and every time a time-out occurs, the system posts a WM_TIMER message to the installing application’s message queue or passes the message to an application-defined TimerProc callback function.
The lpfnTimer callback function need not be named TimerProc, but it must be defined as follows:
void CALLBACK EXPORT TimerProc(
HWND hWnd, // handle of CWnd that called SetTimer
UINT nMsg, // WM_TIMER
UINT nIDEvent // timer identification
DWORD dwTime // system time
);
Timers are a limited global resource; therefore it is important that an application check the value returned by the SetTimer member function to verify that a timer is actually available.
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See Also WM_TIMER, CWnd::KillTimer, ::SetTimer