Sending
System-Exclusive Messages
MIDI
system-exclusive messages are the only MIDI messages that will not fit into a
single doubleword value. System-exclusive messages can be any length. Windows
provides the midiOutLongMsg
function for sending system-exclusive messages to MIDI output devices. To
specify MIDI system-exclusive data blocks, use the MIDIHDR structure.
After you
send a system-exclusive data block using midiOutLongMsg, you must wait
until the device driver is finished with the data block before freeing it. If
you are sending multiple data blocks, you must monitor the completion of each
data block so you know when to send additional blocks. For information about
different techniques for monitoring data-block completion, see Managing MIDI
Data Blocks.
Note Any MIDI
status byte other than a system-real-time message will terminate a
system-exclusive message. If you are using multiple data blocks to send a
single system-exclusive message, do not send any MIDI messages other than
system-real-time messages between data blocks.