Hi there I thought the minimum CPU requirements to run
x86intrin.h
_rdseed64_step(&temp2);
error: inlining failed in call to always_inline 'int _rdseed64_step(long long unsigned int*)': target specific option mismatch
march=native
From Intel knowledge base:
The corresponding 4th Generation Intel® Core™ instruction is RDSEED.
So it looks like you can not use it on 3th gen processor.