Microsoft DirectX 9.0

MIDI System Messages

System messages are not exclusive to any channel. There are three kinds, as shown in the following table.

Message type Purpose
System common Miscellaneous commands and data
System exclusive Equipment-specific commands and data
System real-time Synchronization of clock-based MIDI equipment

Unlike other MIDI messages, system exclusive messages can contain any number of data bytes. After transmitting the data, the sequencer sends a system common message called an EOX, which signals the end of the system exclusive message.

In DirectMusic, the DMUS_SYSEX_PMSG structure contains the length of the data and a pointer to an array of data bytes.