MIDITHRONCONNECTIONCREATE xcode

我用coreMIDI和Xcode为“midithronnectioncreate”尝试了这个方法，但它不起作用。 MIDI In和MIDI Out正在工作，但不是MIDI Thru。谢谢你的帮助

- (void) midiThru
{
    MIDIThruConnectionParams params;
    CFDataRef dataRef;

    #if __LP64__
        typedef MIDIObjectRef MIDIThruConnectionRef;
    #else
        typedef struct OpaqueMIDIThruConnection * MIDIThruConnectionRef;
    #endif

    MIDIThruConnectionRef thru;

    MIDIThruConnectionParamsInitialize(&params);
    params.numSources = 1;
    params.sources[0].endpointRef = sourceMIDI;
    params.numDestinations = 1;
    params.destinations[0].endpointRef = destMIDI;
    dataRef = CFDataCreate(NULL, (unsigned char*) &params,
                                 sizeof(MIDIThruConnectionParams));
    s = MIDIThruConnectionCreate(NULL, dataRef, &thru);

    CFRelease(dataRef);
}