Opening MIDI Output Devices

To open a MIDI output device for playback, use the midiOutOpen function. This function opens the device associated with the specified device identifier and returns a handle of the open device by writing the handle to a specified memory location.

One of the parameters of midiOutOpen is a doubleword value. This value specifies a window or thread handle, an event handle, or the address of a callback function that is used to monitor the progress of the playback of MIDI system-exclusive data and stream buffers. Monitoring enables the application to determine when to send additional data blocks and when to free data blocks that have been sent. For more information about these methods, see Managing MIDI Data Blocks.