No results from cuda calls

I’m starting to investigate using CUDA, but am having difficulty getting any results back from my cuda device. I am running on fedora 32 and using gcc 9.3.0 fith the standars fedora cuda packages. Whatever I try I only ever seem to get zeros back from cuda. I have attached the source file (rename as I couldn’t attach .cu files) the build log and the run output. Any help would be greatly appreciated.

simple.cpp (7.8 KB) build.txt (4.6 KB) run.txt (2.2 KB)