WM_TIMER message

Posted to the installing thread's message queue when a timer expires. The message is posted by the GetMessage or PeekMessage function.

#define WM_TIMER                        0x0113

wParam [in]

The timer identifier.

lParam [in]

A pointer to an application-defined callback function that was passed to the SetTimer function when the timer was installed.

Type: LRESULT

An application should return zero if it processes this message.

You can process the message by providing a WM_TIMER case in the window procedure. Otherwise, DispatchMessage will call the TimerProc callback function specified in the call to the SetTimer function used to install the timer.

The WM_TIMER message is a low-priority message. The GetMessage and PeekMessage functions post this message only when no other higher-priority messages are in the thread's message queue.

Reference

GetMessage

PeekMessage

SetTimer

TimerProc

Conceptual

Timers