BOOL PostMessage( UINT message, WPARAM wParam = 0, LPARAM lParam = 0 );
See PostMessage in the Win32 SDK.
Remarks
Places a message in the message queue associated with the thread that created the window. Returns without waiting for the thread to process the message.
Example
//The following example attaches an HWND to the CWindow object and
//posts a WM_PAINT message to the Window wrapped by the CWindow object
//using CWindow::PostMessage() with the default values of WPARAM and
//LPARAM
CWindow myWindow;
myWindow.Attach(hWndFoo);
myWindow.PostMessage(WM_PAINT);