LRESULT SendMessage( HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);hWnd[in] Handle to the window whose window procedure will receive the message. If this parameter is HWND_BROADCAST, the message is sent to all top-level windows in the system, including disabled or invisible unowned windows, overlapped windows, and pop-up windows; but the message is not sent to child windows.Msg[in] Specifies the message to be sent.wParam[in] Specifies additional message-specific information.lParam[in] Specifies additional message-specific information.