Opencl Segmentation fault while accessing device info - parallel-processing

Question

I'm a newbie in OpenCL programming.
My very first program is giving me a hard time. I wanted to query device name and vendor name of every device in each platform. My system has two platforms, the first one is AMD platform and the second is NVIDIA CUDA platform. I've written the following code to get the desired info.
int main(int argc, char **argv) {
try {
vector<cl::Platform>platforms;
cl::Platform::get(&platforms);
cl_context_properties properties[] = {CL_CONTEXT_PLATFORM, (cl_context_properties)(platforms[0])(), 0};
cl::Context context(CL_DEVICE_TYPE_ALL, properties);
vector<cl::Device> devices = context.getInfo<CL_CONTEXT_DEVICES>();
string dName(devices[0].getInfo<CL_DEVICE_NAME>());
string vendor(devices[0].getInfo<CL_DEVICE_VENDOR>());
cout<<"\tDevice Name:"<<dName<<endl;
cout<<"\tDevice Vendor: "<<vendor<<endl;
}catch(cl::Error err) {
cerr<<err.what()<<" error: "<<printErrorString(err.err())<<endl;
return 0;
}
}
when I change the platform index to 1 in
cl_context_properties properties[] = {CL_CONTEXT_PLATFORM, (cl_context_properties)(platforms[0])(), 0};
my program crashes with 'Segmentation fault'.
I really appreciate your help.
Thanks!

Answer 1

I suspect that you are using the cl.hpp header file from the AMD APP SDK? If that is the case then the problem is that the header file calls an OpenCL 1.2 function (can't remember which one) that is supplied by the AMD devices in your system but not by the Nvidia GPU. Your Nvidia GPU only supports OpenCL 1.1. The best solution I know is to use the header files for OpenCL 1.1 from the Khronos website.