| DirectX SDK |
System messages are not exclusive to any channel. They are of 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.
DirectX for Visual Basic does not give applications direct access to system-exclusive messages.