没有以前的功能原型

Question

我将this tone generation code添加到我现有的项目中，但我做错了，无法弄清问题是什么。该代码在独立项目中运行良好。

OSStatus RenderTone(
    void *inRefCon, 
    AudioUnitRenderActionFlags *ioActionFlags, 
    const AudioTimeStamp *inTimeStamp, 
    UInt32 inBusNumber, 
    UInt32 inNumberFrames, 
    AudioBufferList *ioData)

{
    // Fixed amplitude is good enough for our purposes
    const double amplitude = 0.25;

    // Get the tone parameters out of the view controller
    ToneGeneratorViewController *viewController =
        (ToneGeneratorViewController *)inRefCon;
    double theta = viewController->theta;
    double theta_increment =
        2.0 * M_PI * viewController->frequency / viewController->sampleRate;

    // This is a mono tone generator so we only need the first buffer
    const int channel = 0;
    Float32 *buffer = (Float32 *)ioData->mBuffers[channel].mData;

    // Generate the samples
    for (UInt32 frame = 0; frame < inNumberFrames; frame++) 
    {
        buffer[frame] = sin(theta) * amplitude;

        theta += theta_increment;
        if (theta > 2.0 * M_PI)
        {
            theta -= 2.0 * M_PI;
        }
    }

    // Store the updated theta back in the view controller
    viewController->theta = theta;

    return noErr;
}

在我添加代码的控制器中，我只有警告说No previous prototype for function 'RenderTone'（重复）

我也遇到了一些错误，但这些错误并不在我自己编写的源文件中：

知道可能导致这些的原因吗？

Answer 1

将AudioToolbox.framework添加到您的项目中。