OpenCL 的函数 clGetPlatformInfo 运行时问题。 Win10、VS2012

Question

我的硬件是 Intel Core I7 6700、32 GB RAM、Nvidia GT1030。我的软件是Windows 10 64位，Visual Studio 2012 professional。我买了《OpenCL并行编程开发手册》这本书。不幸的是我在编译程序时遇到问题。程序执行在行结束（第一次调用 clGetPlatformInfo）

error = clGetPlatformInfo(id, param_name, 0, NULL, &paramSize);

#define CL_TARGET_OPENCL_VERSION 120
#include "windows.h"
#include <stdio.h>
#include <stdlib.h>
#include "CL/cl.h"
#include "CL/cl_platform.h"
#include "malloc.h"
#include "resconsts.h"
 
#include <iostream>
#include <fstream>
using namespace std;
static ofstream fout ("log_main_cpp.txt");
 
typedef unsigned char Byte;
 
void displayPlatformInfo(cl_platform_id id, cl_platform_info param_name,
  const char* paramNameAsStr) 
{
  cl_int error = 0;
  size_t paramSize = 0;
  error = clGetPlatformInfo(id, param_name, 0, NULL, &paramSize);  
  char* moreInfo = (char*) malloc(paramSize);
  error = clGetPlatformInfo(id, param_name, paramSize, moreInfo, NULL);
  if (error != CL_SUCCESS)
    fout << "Unable to find any OpenCL Platform information";
  fout << "paramNameAsStr = " << paramNameAsStr << endl 
    << "moreInfo = " << moreInfo << endl; 
}
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
  LPSTR lpCmdLine, int nCmdShow) 
{
  cl_platform_id *platforms;
  cl_uint numOfPlatforms;
  cl_int error;
  error = clGetPlatformIDs(0, NULL, &numOfPlatforms);
  if (error < 0) {
    fout << "Unable to find any OpenCL platforms" << endl;
    exit(1);
  }
  // Allocate memory for the number of installed platforms.
  // alloca(...) occupies some stack space but is auromatically freed on return.
  platforms = (cl_platform_id*) alloca (sizeof(cl_platform_id)*numOfPlatforms);
  fout << "Number of OpenCL platforms found: " << numOfPlatforms << endl;
  // We invoke the API 'clPlatformInfo' twice for each parameter we're trying 
  // to extract and we use the return value to create temporary data structures
  // (on the stack) to store the returned information on the second invocation.
  for (cl_uint i = 0; i < numOfPlatforms; i++) {
    displayPlatformInfo(platforms[i], CL_PLATFORM_PROFILE,
      "CL_PLATFORM_PROFILE");
    displayPlatformInfo(platforms[i], CL_PLATFORM_VERSION,
      "CL_PLATFORM_VERSION");
    displayPlatformInfo(platforms[i], CL_PLATFORM_NAME,
      "CL_PLATFORM_NAME");
    displayPlatformInfo(platforms[i], CL_PLATFORM_VENDOR,
      "CL_PLATFORM_VENDOR");
    displayPlatformInfo(platforms[i], CL_PLATFORM_EXTENSIONS,
      "CL_PLATFORM_EXTENSIONS");
  }
  
  return 0;
}

在“Linker->Input->Additional Dependency”中添加“OpenCL.lib”后程序编译成功。

Answer 1

你永远不会填充

platforms

，所以使用它是未定义的行为：

error = clGetPlatformIDs(numOfPlatforms, platforms, nullptr);

在

clGetPlatformInfo

上调用

malloc

之前，您还需要检查

paramSize

的结果，如果

clGetPlatformInfo

失败，则可能没有设置

paramSize

。