Sent to a MIDI output device driver to deallocate a specified device.
| MMSYSERR_NOTENABLED | The driver failed to load or initialize. |
| MIDIERR_STILLPLAYING | There are still buffers in the queue. |
If there are output buffers that have been received with the MODM_LONGDATA message and haven't been returned to the application, the driver should fail the close operation by returning a MIDIERR_STILLPLAYING error. If the close operation is successful, the driver should use the DriverCallback function to send the client a MOM_CLOSE message.
MODM_OPEN