PPL管道中的访问冲突

Question

我正在使用异步代理库来实现简单的图像处理管道 我有三个代理人

1. CLoadBitmapAgent
2. CConvertToGrayAgent
3. CSaveBitmapAgent

每个run（）函数如下

void CLoadBitmapAgent::run()
{
Bitmap *pSourceBitmap = new Bitmap(m_imagePath);
asend(m_target,pSourceBitmap);
done();
}

void CConvertToGrayAgent::run()
{
BitmapUtilities bitmapUtilities;
Bitmap *pSourceBitmap = receive(m_source);
bitmapUtilities.ParallelConvertToGray(pSourceBitmap);
asend(m_target,pSourceBitmap);
done();

}

void CSaveBitmapAgent::run()
{
Bitmap * bitmap = receive(m_source);
BitmapUtilities bitmapUtilities;
CLSID clsid; 
bitmapUtilities.GetEncoderClsid(L"image/jpeg",clsid);
bitmap->Save(L"D:\\final_image.jpg",&clsid);
done();
}

这是我测试此管道的代码

    wchar_t * wcs = L"D:\\Photos\\z.jpg";


    unbounded_buffer<Bitmap*> buffer1;
    unbounded_buffer<Bitmap*> buffer2;


    CLoadBitmapAgent loadBitmapAgent(wcs,buffer1);
    CConvertToGrayAgent convertToGrayAgent(buffer1,buffer2);
    CSaveBitmapAgent saveBitmapAgent(buffer2);

    loadBitmapAgent.start();
    convertToGrayAgent.start();
    saveBitmapAgent.start();
    agent * agents[3] = {&loadBitmapAgent,&convertToGrayAgent,&saveBitmapAgent};
    agent::wait_for_all(4,agents);

问题是我在此行中遇到访问冲突异常     剂:: wait_for_all（4，代理）; 是什么导致这个异常，我该如何解决它 谢谢