MIDI output messages are sent by audio device drivers to an application to inform the application about the status of MIDI output operations. By specifying flags with the midiOutOpen function, applications may choose to have messages sent either to a window or to a low-level callback function. Use these messages to manage MIDI output:
MM_MOM_CLOSE
Sent to a window when a MIDI output device is closed.
MM_MOM_DONE
Sent to a window when a MIDI system exclusive data block has been played and is being returned to the application.
MM_MOM_OPEN
Sent to a window when a MIDI output device is opened.
MOM_CLOSE
Sent to a low-level callback function when a MIDI output device is closed.
MOM_DONE
Sent to a low-level callback function when a MIDI system exclusive data block has been played and is being returned to the application.
MOM_OPEN
Sent to a low-level callback function when a MIDI output device is opened.