c++ - 尝试为图像缓冲区分配内存时错误的 ptr 值

Question

unsigned char* createImageBuffer(unsigned int bytes)
{
    unsigned char* ptr;
    cudaSetDeviceFlags(cudaDeviceMapHost);
    cudaHostAlloc(&ptr, bytes, cudaHostAllocMapped);    
    return ptr;
}


    cv::Mat sGray(frame.size(), CV_8U, createImageBuffer(frame.size().width * frame.size().height));

    cv::Mat dGray(frame.size(), CV_8U, createImageBuffer(frame.size().width * frame.size().height));

    cv::Mat eGray(frame.size(), CV_8U, createImageBuffer(frame.size().width * frame.size().height));

调试期间的问题与访问 0x00000000 处的受限内存有关。该函数应该返回一个指向图像字节分配位置的指针，但是它给了我错误的 ptr 值。

输出:

First-chance exception at 0x0c10e473 in improc.exe: 0xC0000005: Access violation reading location 0x00000000. Unhandled exception at 0x0c10e473 in improc.exe: 0xC0000005: Access violation reading location 0x00000000.

我关注的教程视频:https://youtu.be/j9vb5UjQCQg

Answer 1

API 可能无法分配足够的内存。检查 cudaHostAlloc 的返回值(参见 doku on cudaHostAlloc ):

unsigned char* createImageBuffer(unsigned int bytes)
{
    unsigned char* ptr;
    cudaSetDeviceFlags(cudaDeviceMapHost);
    cudaError_t allocResult = cudaHostAlloc(&ptr, bytes, cudaHostAllocMapped);
    if (allocResult != cudaSuccess) {
      // could be cudaErrorMemoryAllocation; The API call failed because
      // it was unable to allocate enough memory to perform
      // the requested operation.
      return nullptr;
    }
    return ptr;
}