No audio out with simple MIDI routing

Question

With the following code I'm trying to send a MIDI-Event to an NSLog Synth:

MIDIClientRef midiClient = NULL;

MIDIClientCreate(
    CFSTR("MidiClient"),
    NULL,
    NULL,
    &midiClient
);

MIDIPortRef midiClientOutPort = NULL;

MIDIOutputPortCreate(
    midiClient,
    CFSTR("MidiClientPort"),
    &midiClientOutPort
);

NSLog(@"%lu", MIDIGetNumberOfDestinations());

MIDIEndpointRef endpoint = NULL;

endpoint = MIDIGetDestination(1);

CFPropertyListRef plist = NULL;
MIDIObjectGetProperties(endpoint, &plist, YES);

NSArray *temp = [NSArray arrayWithObject:(__bridge id)(plist)];
NSLog(@"%@", [temp description]);

MIDIPacketList packet;
packet.numPackets = 1;
packet.packet[0].data[0] = 0x90;
packet.packet[0].data[1] = 0x3c;
packet.packet[0].data[2] = 0x40;
packet.packet[0].timeStamp = 0;

MIDISend(midiClientOutPort, endpoint, &packet);

If I check OSStatus I get no errors. I get a MIDIClient, a MIDIOutputPort and the MIDISend is also fine. Additionally I get the synth destination with no errors. The synth is listening to all midi channels and if I test with a sequencer to synth responds with audio. I execute the code with a button press but nothing happens.

What doing I'm wrong?

Answer 1

The solution:

MIDIPacketList packet;
packet.numPackets = 1;
packet.packet[0].timeStamp = 0;
packet.packet[0].length = 3;
packet.packet[0].data[0] = 0x90;
packet.packet[0].data[1] = 0x3c;
packet.packet[0].data[2] = 0x40;

I have to set the length property!