long platform = pb.get(0);
NativeSizeBuffer properties = NativeSizeBuffer.allocateDirect(3).put(CL.CL_CONTEXT_PLATFORM)
.put(platform).put(0) // 0 terminated array
.rewind();
long context = cl.clCreateContextFromType(properties, CL.CL_DEVICE_TYPE_ALL, null, null);
out.println("context handle: "+context);
checkError("on clCreateContextFromType", ret);
NativeSizeBuffer longBuffer = NativeSizeBuffer.allocateDirect(1);
ret = cl.clGetContextInfo(context, CL.CL_CONTEXT_DEVICES, 0, null, longBuffer);