The MIDI 1.0 Specification allows the use of running-status when a message has the same status byte as the previous message. When running status is used, the status byte of subsequent messages can be omitted. You can send MIDI messages using running status with both midiOutShortMsg and midiOutLongMsg. To send a message using running status with midiOutShortMsg, pack the message into a DWORD, as shown in the following illustration:
To send a message using running status with midiOutLongMsg, pack the bytes into the data block with the most significant byte coming first—no DWORD padding is used.