goto + macro

gistfile1.m

#define FAIL_ON_ERR(_X_) if ((status = (_X_)) != noErr) { goto failed; }

- (BOOL)play:(NSError **)error;
{
    NSAssert(_graph == NULL, @"Graph is already started");

    OSStatus status;
    
    FAIL_ON_ERR(NewAUGraph(&_graph));
    FAIL_ON_ERR([self addOutputNode]);
    FAIL_ON_ERR([self addConverterNode]);
    FAIL_ON_ERR(AUGraphConnectNodeInput(_graph, _converterNode, 0, _outputNode, 0));
    FAIL_ON_ERR(AUGraphOpen(_graph));
    [self setupDataFormat];
    FAIL_ON_ERR([self setDataFormatOfConverterAudioUnit]);
    FAIL_ON_ERR([self setMaximumFramesPerSlice]);
    FAIL_ON_ERR([self setRenderCallbackOfConverterNode]);
    FAIL_ON_ERR(AUGraphInitialize(_graph));
    A440SineWaveGeneratorInitWithFrequency(&_sineWaveGenerator, 440.0);
    FAIL_ON_ERR(AUGraphStart(_graph));
    
    return YES;
    
failed:
    if (_graph != NULL) {
        DisposeAUGraph(_graph);
    }
    
    if (error != NULL) {
        *error = [NSError errorWithDomain:NSOSStatusErrorDomain code:status userInfo:nil];
    }
    return NO;
}