midtest.m

/* 
   midtest.m
   example OS X CoreMIDI code; generates an unattractive stream of random notes

   compile me with 
      gcc -framework Foundation -framework CoreMIDI midtest.m -o mt

   Then run mt and set the input MIDI track for your favorite
   synthesizer to "random notes;" enjoy (?) random notes

   Comments/flames to Will Benton (google me); this code is in the public domain.
*/

#include <stdlib.h>
#include <pthread.h>
#include <Cocoa/Cocoa.h>
#include <Foundation/Foundation.h>
#include <CoreMIDI/CoreMIDI.h>

void send_midi_note(MIDIEndpointRef midiEndpoint, Byte channel, Byte note, Byte vel) {
	Byte buffer[128];
	MIDIPacketList *pktlist = (MIDIPacketList*)buffer;
	MIDIPacket *curPacket = MIDIPacketListInit(pktlist);

	Byte message[] = {(channel & 0x0f) | 0x90, // take either a MIDI channel (90-9f) or a small integer
		note, 
		vel};
	
	curPacket = MIDIPacketListAdd(pktlist, sizeof(buffer), curPacket, 0, 3, message);
	MIDIReceived(midiEndpoint, pktlist);
}

int main(int argc, char *argv[]) {
    MIDIClientRef midiClient;
    MIDIEndpointRef midiEndpoint;

    MIDIClientCreate(@"miditest", NULL, NULL, &midiClient);
    MIDISourceCreate(midiClient, @"random notes", &midiEndpoint);

    while(true) {		
		Byte note = random() % 127;

		send_midi_note(midiEndpoint, 0, note, 127);  // note on at velocity 127

		sleep(1);  // don't try this in a real application!

		send_midi_note(midiEndpoint, 0, note, 0);  // note off (at velocity 0)
	}
    
    exit(0);
}