List audio devices on OS X

audio_devices.m

NSArray* audioDevices() {
    AudioObjectPropertyAddress propertyAddress = {
        kAudioHardwarePropertyDevices,
        kAudioObjectPropertyScopeGlobal,
        kAudioObjectPropertyElementMaster
    };

    UInt32 dataSize = 0;
    OSStatus status = 0;

    status = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize);
    if (kAudioHardwareNoError != status) {
        NSLog(@"AudioObjectGetPropertyDataSize (kAudioHardwarePropertyDevices) failed: %i", status);
    }

    AudioDeviceID *audioDevices = malloc(dataSize);

    status = AudioObjectGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &dataSize, audioDevices);
    if (kAudioHardwareNoError != status) {
        NSLog(@"AudioObjectGetPropertyData (kAudioHardwarePropertyDevices) failed: %i", status);
    }
    if (sizeof(audioDevices) != dataSize) {
        NSLog(@"AudioObjectGetPropertyData (kAudioHardwarePropertyDevices) did not fill the outData buffer");
    }

    UInt32 deviceCount = dataSize / sizeof(AudioDeviceID);
    NSMutableArray *inputInterfaces = [NSMutableArray arrayWithCapacity:deviceCount];

    propertyAddress.mSelector = kAudioObjectPropertyName;
    for (UInt32 i = 0; i < deviceCount; ++i) {
        CFStringRef deviceName = NULL;
        dataSize = sizeof(deviceName);
        status = AudioObjectGetPropertyData(audioDevices[i], &propertyAddress, 0, NULL, &dataSize, &deviceName);
        if (kAudioHardwareNoError != status) {
            NSLog(@"AudioObjectGetPropertyData (kAudioObjectPropertyName) failed: %i", status);
            continue;
        }
        if (sizeof(deviceName) != dataSize) {
            NSLog(@"AudioObjectGetPropertyData (kAudioObjectPropertyName) did not fill the outData buffer");
        }

        [inputInterfaces addObject:(__bridge NSString *)deviceName];
    }

    free(audioDevices), audioDevices = NULL;

    return [NSArray arrayWithArray:inputInterfaces];
}