pszCommandBuf (PSZ) - input

Media control command string of the form:

    <command> <object> <keywords>

The object can be the device type, file name, alias, and so forth.

pszReturnString (PSZ) - output

A application-supplied buffer for the return data. This pointer can be NULL if no return information is desired. For more information see String Commands.

usReturnLength (USHORT) - input

The number of bytes reserved for pszReturnString.

hwndCallBack (HWND) - input

A PM window handle to be used in returning asynchronous notification messages. This parameter must be specified if notify was specified in the command string.

usUserParm (USHORT) - input

User parameter returned in the notification for this message.

rc (ULONG) - returns

Returns MCIERR_SUCCESS in the low-order word if there was no error; otherwise it returns an error code in the low-order word of the return value. Use mciGetErrorString to convert this code to a string. If the error code is a device-dependent error, the high-order word will contain the device ID.