rc (ULONG) - returns

Returns MCIERR_SUCCESS in the low-order word if there was no error; otherwise it returns the error code in the low-order word of the return value.

Use mciGetErrorString to convert this code to a textual string. If the return code is a device-dependent error, the high-order word will contain the device ID. See Return Codes for a listing of possible return values. If the MCI_NOTIFY flag is specified then the device receiving this message performs error checking to see if it can begin processing the message. The amount of required error checking varies depending on the message and device. The device returns to the application and the rest of the command processing occurs asynchronously.