#include <stdio.h>
#include <stdlib.h>
 
#ifdef __APPLE__
#include <OpenCL/opencl.h>
#else
#include <CL/cl.h>
#endif
 
#define MEM_SIZE (128)
#define MAX_SOURCE_SIZE (0x100000)
 
int main()
{
    cl_device_id device_id = NULL;
    cl_context context = NULL;
    cl_command_queue command_queue = NULL;
    cl_mem memobj = NULL;
    cl_program program = NULL;
    cl_kernel kernel = NULL;
    cl_platform_id platform_id = NULL;
    cl_uint ret_num_devices;
    cl_uint ret_num_platforms;
    cl_int ret;
 
    char string[MEM_SIZE];
 
    FILE *fp;
    char fileName[] = "./hello.cl";
    char *source_str;
    size_t source_size;
 
/* Load the source code containing the kernel*/
    fp = fopen(fileName, "r");
    if (!fp) {
        fprintf(stderr, "Failed to load kernel.\n");
        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 Info */
    ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
    ret = clGetDeviceIDs(platform_id, CL_DEVICE_TYPE_DEFAULT, 1, &device_id, &ret_num_devices);
 
/* Create OpenCL context */
    context = clCreateContext(NULL, 1, &device_id, NULL, NULL, &ret);
 
/* Create Command Queue */
    command_queue = clCreateCommandQueue(context, device_id, 0, &ret);
 
/* Create Memory Buffer */
    memobj = clCreateBuffer(context, CL_MEM_READ_WRITE,MEM_SIZE * sizeof(char), NULL, &ret);
 
/* Create Kernel Program from the source */
    program = clCreateProgramWithSource(context, 1, (const char **)&source_str,
                                        (const size_t *)&source_size, &ret);
 
/* Build Kernel Program */
    ret = clBuildProgram(program, 1, &device_id, NULL, NULL, NULL);
 
/* Create OpenCL Kernel */
    kernel = clCreateKernel(program, "hello", &ret);
 
/* Set OpenCL Kernel Parameters */
    ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void *)&memobj);
 
/* Execute OpenCL Kernel */
    ret = clEnqueueTask(command_queue, kernel, 0, NULL,NULL);
 
/* Copy results from the memory buffer */
    ret = clEnqueueReadBuffer(command_queue, memobj, CL_TRUE, 0,
                              MEM_SIZE * sizeof(char),string, 0, NULL, NULL);
 
/* Display Result */
    puts(string);
 
/* Finalization */
    ret = clFlush(command_queue);
    ret = clFinish(command_queue);
    ret = clReleaseKernel(kernel);
    ret = clReleaseProgram(program);
    ret = clReleaseMemObject(memobj);
    ret = clReleaseCommandQueue(command_queue);
    ret = clReleaseContext(context);
 
    free(source_str);
 
    return 0;
}