Why doesn't this simple CoreMIDI program produce MIDI output?

Question

Here is an extremely simple CoreMIDI OS X application that sends MIDI data. The problem is that it doesn\'t work. It compiles fine, and runs. It reports no errors, and does

Answer 1

I'm just leaving this here for my own reference. It's a full example based 100% on yours, but including the other side (receiving), my bad C code and the accepted answer's corrections (of course).

#import "AppDelegate.h"

@implementation AppDelegate

@synthesize window = _window;

#define NSLogError(c,str) do{if (c) NSLog(@"Error (%@): %u:%@", str, (unsigned int)c,[NSError errorWithDomain:NSMachErrorDomain code:c userInfo:nil]); }while(false)

static void spit(Byte* values, int length, BOOL useHex) {
    NSMutableString *thing = [@"" mutableCopy];
    for (int i=0; ipacket[0];

    for (int i = 0; i < packetList->numPackets; i++)
    {

        NSData *data = [NSData dataWithBytes:packet->data length:packet->length];
        spit((Byte*)data.bytes, data.length, YES);

        packet = MIDIPacketNext(packet);
    }
}

- (void) setupReceiver {
    OSStatus s;
    MIDIEndpointRef virtualInTemp;
    NSString *inName = [NSString stringWithFormat:@"Magical MIDI Destination"];
    s = MIDIDestinationCreate(theMidiClient, (__bridge CFStringRef)inName, ReadProc,  (__bridge void *)self, &virtualInTemp);
    NSLogError(s, @"Create virtual MIDI in");
}

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    MIDIClientCreate(CFSTR("Magical MIDI"), NULL, NULL,
                     &theMidiClient);
    [self setupReceiver];
    [self startSending];

}

@end