The MCIWNDM_SENDSTRING message sends an MCI command in string form to the device associated with the MCIWnd window. You can send this message explicitly or by using the MCIWndSendString macro.
MCIWNDM_SENDSTRING
wParam = 0;
lParam = (LPARAM) (LPSTR) sz;
Returns zero if successful or an error otherwise.
The message handler for MCIWNDM_SENDSTRING appends a device alias to the MCI command you send to the device. Therefore, you should not use any alias in an MCI command that you issue with MCIWNDM_SENDSTRING.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in vfw.h.
Unicode: Defined as Unicode and ANSI messages.
MCIWnd Window Class Overview, MCIWnd Messages, MCIWndSendString