问使用cudaMalloc分配的内存显示为‘？’

EN

extern "C" bool
runTest(const int argc, const char **argv, char *data, int2 *data_int2, unsigned int len)
{
    // use command-line specified CUDA device, otherwise use device with highest Gflops/s
    findCudaDevice(argc, (const char **)argv);

    const unsigned int num_threads = len / 4;
    assert(0 == (len % 4));
    const unsigned int mem_size = sizeof(char) * len;
    const unsigned int mem_size_int2 = sizeof(int2) * len;

    // allocate device memory
    char *d_data;
    checkCudaErrors(cudaMalloc((void **) &d_data, mem_size));
    // copy host memory to device
    checkCudaErrors(cudaMemcpy(d_data, data, mem_size,
                               cudaMemcpyHostToDevice));
    ...
    ...
    ...
}