OpenCL Code im trying to get to work

helloworld.cpp

#include <utility>
#define __NO_STD_VECTOR
#include <CL/cl.hpp>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <iterator>
#include <fstream>

const std::string hw("Hello World\n");

inline void
checkErr(cl_int err, const char * name) {
	if (err != CL_SUCCESS) {
		std::cerr << "ERROR: " << name << " (" << err << ")" << std::endl;
		exit(EXIT_FAILURE);
	}
}

int main(void) {
	cl_int err;
	cl::vector< cl::Platform> platformList;
	cl::Platform::get(&platformList);
	checkErr(platformList.size() != 0 ? CL_SUCCESS : -1, "cl::Platform::get");
	std::cerr << "platform number is: " << platformList.size() << std::endl;
	std::string platformVendor;
	platformList[0].getInfo((cl_platform_info)CL_PLATFORM_PROFILE, &platformVendor);
	std::cerr << "platform is by: " << platformVendor << "\n";
	cl_context_properties cprops[3] = {CL_CONTEXT_PLATFORM, (cl_context_properties)(platformList[0])(), 0};
	cl::Context context(CL_DEVICE_TYPE_CPU, cprops, NULL, NULL, &err);
	checkErr(err, "Context::Context");

	char * outH = new char[hw.length()+1];
	cl::Buffer outCL(context, CL_MEM_WRITE_ONLY | CL_MEM_USE_HOST_PTR, hw.length()+1, outH, &err);
	checkErr(err, "Buffer::Buffer()");

	cl::vector<cl::Device> devices;
	devices = context.getInfo<CL_CONTEXT_DEVICES>();
	checkErr(devices.size() > 0 ? CL_SUCCESS : -1, "devices.size() > 0");

	//std::ifstream file("lesson1_kernels.cl");
	std::ifstream file("lesson1_kernels.cl");
	checkErr(file.is_open() ? CL_SUCCESS : -1, "lesson1_kernel.cl");
	std::string prog(std::istreambuf_iterator<char>(file),
			(std::istreambuf_iterator<char>()));
	cl::Program::Sources source(1, std::make_pair(prog.c_str(), prog.length()+1));
	cl::Program program(context, source);
	err = program.build(devices, "");
	checkErr(err, "Program::build()");

	cl::Kernel kernel(program, "hello", &err);
	checkErr(err, "Kernel::Kernel()");
	err = kernel.setArg(0, outCL);
	checkErr(err, "Kernel::setArg()");

	cl::CommandQueue queue(context, devices[0], 0, &err);
	checkErr(err, "CommandQueue::CommandQueue()");
	cl::Event event;
	err = queue.enqueueNDRangeKernel(
			kernel,
			cl::NullRange,
			cl::NDRange(hw.length()+1),
			cl::NDRange(1,1),
			NULL,
			&event);
	checkErr(err, "CommandQueue::enqueueNDRangeKernel()");
	event.wait();
	err = queue.enqueueReadBuffer(outCL, CL_TRUE, 0, hw.length()+1, outH);
	checkErr(err, "CommandQueue::enqueueReadBuffer()");
	std::cout << outH;
	return EXIT_SUCCESS;
}


#pragma OPENCL EXTENSION cl_khr_byte_addressable_store : enable
__constant char hw[] = "Hello World\n";
__kernel void hello(__global char * out) {
	size_t tid = get_global_id(0);
	out[tid] = hw[tid];
}