Sent to a MIDI output device driver to stop output from the output queue and to turn off any notes that are playing.
MMSYSERR_NOTENABLED | The driver failed to load or initialize. |
If the driver's output queue is not empty, it should stop and mark all pending data blocks as done by setting the MHDR_DONE bit in the dwFlags field of the MIDIHDR structure for each block. The driver should then notify the client by using DriverCallback to send a MOM_DONE message for each data block.
If the device is an output port, the driver should send a MIDI note-off event for all 128 notes on all 16 channels. Optionally, the driver can keep track of which notes are turned on and send note-off events only for those notes. In addition, the driver should send a damper pedal off event (controller 0x40) for each channel. If the device is an internal synthesizer, the driver should turn off any notes that are playing.