The
user-application must allocate memory for the device name. If MCI_MAKE_CONNECTION
is specified, this field indicates the device name to which the connection
is to be established. If MCI_QUERY_CONNECTION is specified, and a connection
exists, this field returns the device name to which the connection exists.
If no connection exists, this field is set to NULL on return and the error
MCIERR_NO_CONNECTION is returned.