LONG SendMessage( UINT message, UINT wParam = 0, LONG lParam = 0 );
message
Specifies the message to be sent.
wParam
Specifies additional message information. The content of this parameter depends on the message being sent.
lParam
Specifies additional message information. The content of this parameter depends on the message being sent.
Sends a message to a window or windows. The SendMessage member function calls the window procedure for the current CWnd object and does not return until that window procedure has processed the message. This is in contrast to the PostMessage member function which places the message into the CWnd message queue and returns immediately.
The result returned by the invoked window procedure; its value depends on the message being sent.
::InSendMessage, CWnd::PostMessage, CWnd::SendDlgItemMessage, ::SendMessage