如何解决为什么OpenCL无法链接？
这让我发疯。似乎每个人和他们的母亲都在Internet上的某个地方发布了有关此问题的论坛帖子，并获得了完全相同的解决方案，对我不起作用...
这是我从Internet复制的一个非常基本的“ hello world”类型的示例。我将其命名为cltest.c。
#include <stdio.h>
#include <stdlib.h>
#ifdef __APPLE__
#include <OpenCL/opencl.h>
#else
#include <CL/cl.h>
#endif
#define MAX_SOURCE_SIZE (0x100000)
int main()
{
const int LIST_SIZE = 1024;
int* a = (int*) malloc(sizeof(int) * LIST_SIZE);
int* b = (int*) malloc(sizeof(int) * LIST_SIZE);
int i;
for (i = 0; i < LIST_SIZE; i++)
{
a[i] = i;
b[i] = LIST_SIZE - i;
}
//load the kernel source code into the array source_str
FILE* fp;
char* source_str;
size_t source_size;
fp = fopen("gpu.cl","r");
if (!fp)
{
printf("Failed to load kernel");
exit(1);
}
source_str = (char *)malloc(MAX_SOURCE_SIZE);
source_size = fread(source_str,1,MAX_SOURCE_SIZE,fp);
fclose(fp);
//Get platform and device information
cl_platform_id platform_id = NULL;
cl_device_id device_id = NULL;
cl_uint ret_num_devices;
cl_uint ret_num_platforms;
cl_int ret = clGetPlatformIDs(1,&platform_id,&ret_num_platforms);
ret = clGetDeviceIDs(platform_id,CL_DEVICE_TYPE_GPU,&device_id,&ret_num_devices);
//create an OpenCL context
cl_context context = clCreateContext(NULL,NULL,&ret);
//create a command queue
cl_command_queue command_queue = clCreateCommandQueue(context,device_id,&ret);
//create memory buffers on the device for each vector
cl_mem a_mem_obj = clCreateBuffer(context,CL_MEM_READ_ONLY,LIST_SIZE * sizeof(int),&ret);
cl_mem b_mem_obj = clCreateBuffer(context,&ret);
cl_mem c_mem_obj = clCreateBuffer(context,CL_MEM_WRITE_ONLY,&ret);
//copy a and b to their respective memory buffers
ret = clEnqueueWriteBuffer(command_queue,a_mem_obj,CL_TRUE,a,NULL);
ret = clEnqueueWriteBuffer(command_queue,b_mem_obj,b,NULL);
//create a program from the kernel source
cl_program program = clCreateProgramWithSource(context,(const char **)&source_str,(const size_t *)&source_size,&ret);
//build the program
ret = clBuildProgram(program,NULL);
//create the OpenCL kernel
cl_kernel kernel = clCreateKernel(program,"vector_add",&ret);
//set the arguments of the kernel
ret = clSetKernelArg(kernel,sizeof(cl_mem),(void *)&a_mem_obj);
ret = clSetKernelArg(kernel,(void *)&b_mem_obj);
ret = clSetKernelArg(kernel,2,(void *)&c_mem_obj);
//execute the OpenCL kernel on the list
size_t global_item_size = LIST_SIZE;
size_t local_item_size = 64;
ret = clEnqueueNDRangeKernel(command_queue,kernel,&global_item_size,&local_item_size,NULL);
//read memory buffer c on the device to the local variable c
int* c = (int *)malloc(sizeof(int) * LIST_SIZE);
ret = clEnqueueReadBuffer(command_queue,c_mem_obj,c,NULL);
//display the result to the screen
for (i = 0; i < LIST_SIZE; i++)
{
printf("%d + %d = %d\n",a[i],b[i],c[i]);
}
//clean up
ret = clFlush(command_queue);
ret = clFinish(command_queue);
ret = clReleaseKernel(kernel);
ret = clReleaseProgram(program);
ret = clReleaseMemObject(a_mem_obj);
ret = clReleaseMemObject(b_mem_obj);
ret = clReleaseMemObject(c_mem_obj);
ret = clReleaseContext(context);
free(a);
free(b);
free(c);
return 0;
}
要构建，我正在使用命令
gcc -v -Wl,--verbose -H cltest.c -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\include" -L"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\lib\x64" -lOpenCL
这会生成1021行消息，但以下是（我认为）相关的消息：
(...)
#include "..." search starts here:
#include <...> search starts here:
C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\include
c:\mingw\bin\../lib/gcc/mingw32/9.2.0/include
c:\mingw\bin\../lib/gcc/mingw32/9.2.0/../../../../include
c:\mingw\bin\../lib/gcc/mingw32/9.2.0/include-fixed
End of search list.
GNU C17 (MinGW.org GCC Build-20200227-1) version 9.2.0 (mingw32)
compiled by GNU C version 9.2.0,GMP version 6.1.2,MPFR version 4.0.2,MPC version 1.1.0,isl version isl-0.21-GMP
(...)
. C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\include/CL/cl.h
.. C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\include/CL/cl_platform.h
... c:\mingw\lib\gcc\mingw32\9.2.0\include\stdint.h
.... c:\mingw\include\stdint.h
..... c:\mingw\lib\gcc\mingw32\9.2.0\include\stddef.h
... c:\mingw\lib\gcc\mingw32\9.2.0\include\stddef.h
(...)
C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o
attempt to open C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\lib\x64/libOpenCL.dll.a failed
attempt to open C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\lib\x64/OpenCL.dll.a failed
attempt to open C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\lib\x64/libOpenCL.a failed
attempt to open C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.0\lib\x64/OpenCL.lib succeeded
(...)
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x11b): undefined reference to `clGetPlatformIDs@12'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x152): undefined reference to `clGetDeviceIDs@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x18a): undefined reference to `clCreateContext@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x1b9): undefined reference to `clCreateCommandQueue@20'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x1f7): undefined reference to `clCreateBuffer@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x235): undefined reference to `clCreateBuffer@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x273): undefined reference to `clCreateBuffer@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x2c8): undefined reference to `clEnqueueWriteBuffer@36'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x31d): undefined reference to `clEnqueueWriteBuffer@36'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x34b): undefined reference to `clCreateProgramWithSource@20'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x383): undefined reference to `clBuildProgram@24'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x3a3): undefined reference to `clCreateKernel@12'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x3cb): undefined reference to `clSetKernelArg@16'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x3f3): undefined reference to `clSetKernelArg@16'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x41b): undefined reference to `clSetKernelArg@16'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x476): undefined reference to `clEnqueueNDRangeKernel@36'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x4dc): undefined reference to `clEnqueueReadBuffer@36'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x54d): undefined reference to `clFlush@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x55e): undefined reference to `clFinish@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x56f): undefined reference to `clReleaseKernel@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x580): undefined reference to `clReleaseProgram@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x591): undefined reference to `clReleaseMemObject@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x5a2): undefined reference to `clReleaseMemObject@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x5b3): undefined reference to `clReleaseMemObject@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: C:\Users\Devsman\AppData\Local\Temp\ccwXijlf.o:cltest.c:(.text+0x5c4): undefined reference to `clReleaseContext@4'
c:/mingw/bin/../lib/gcc/mingw32/9.2.0/../../../../mingw32/bin/ld.exe: link errors found,deleting executable `a.exe'
(...)
我已经多次更改了每个参数的顺序，已经对指定文件的目录进行了两次，三重和四重检查，我取出了-o标志，以防万一，我尝试编译cltest.c到一个对象，然后在一个单独的调用中将它们链接起来，我就没主意了！希望有一个简单的修复程序是如此基本/显而易见，我想不起来了。预先感谢。
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