MODM_STOP

Sent to a MIDI output device driver to stop output from the output queue and to turn off any notes that can be playing.

Returns zero if the operation is successful. Otherwise, it returns an error number. Possible error values include the following:

MMSYSERR_NOTENABLED

The driver failed to load or initialize.

dwParam1: Unused.
dwParam2: Unused.

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.

The driver should send a note off for all notes which are currently turned on. 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 playing.