const char * cluErrorString(cl_int error);
unsigned cluInitGpuDevice(cl_device_id * device_id);
unsigned cluCreateKernel(cl_context context, cl_device_id device_id,
                         cl_kernel * kernel, const char * kernel_name);
unsigned cluKernelSetArg(cl_kernel kernel, cl_uint index, size_t size,
                         const void * value);