C OpenCL example wich lists platforms and devices

opencl-list.c

#include <stdio.h>
#include <CL/cl.h>

#define BUFFERSIZE		1024
#define MAX_PLATFORMS		8	
#define MAX_DEVICES		8
 
//gcc -o opencl opencl-list.c -lOpenCL &&  ./opencl 
 
int main(int argc, char** argv)
{
	
    char buffer[BUFFERSIZE];
    cl_int err;                           
    cl_device_id device_id;             
    cl_device_id devices[MAX_DEVICES];          
    cl_uint num;
    cl_platform_id platforms[MAX_PLATFORMS];
 

    err =  clGetPlatformIDs(MAX_PLATFORMS, platforms, &num);
    printf ("Num Platforms: %d\n", num);
    if (err != CL_SUCCESS)
    {
        printf("Error: Failed getting platforms.\n");
        return EXIT_FAILURE;
    }
     
     
 // Search for platforms devices and set a default gpu device    
    for (int i = 0; i < num; i++){
		
		
		cl_uint n;
		cl_device_type type;
		clGetPlatformInfo(platforms[i],CL_PLATFORM_NAME,1024,buffer,NULL);
		printf ("Platform name: %s\n", buffer );	
		//clGetPlatformInfo(platforms[i],CL_PLATFORM_EXTENSIONS,1024,buffer,NULL);
		//printf ("  Platform Extensions: %s\n", buffer );
		
		err = clGetDeviceIDs(platforms[i], CL_DEVICE_TYPE_ALL, MAX_DEVICES, devices, &n);
		if (err != CL_SUCCESS)
		{
			printf("Error: Failed to create a device group!\n");
			return EXIT_FAILURE;
		}	
		
		for (int d = 0; d < n; d++){
			clGetDeviceInfo(devices[i],CL_DEVICE_NAME,1024,buffer,NULL);
			printf ("    Device Name: %s\n", buffer );
			clGetDeviceInfo(devices[i],CL_DEVICE_TYPE,1024,&type,NULL);
			printf ("    Device Type: %d\n", type );
			
			// Set device_id with the first GPU device found
			if (type & CL_DEVICE_TYPE_GPU) {
				device_id = devices[i];
			}			
		}		
	}
  
  
    
	clGetDeviceInfo(device_id,CL_DEVICE_NAME,1024,buffer,NULL);
	printf ("\nUsing Device Name: %s\n", buffer );
  
    return 0;
}