Thanks for the details. If you are reading from a shared variable like that you most definitely need to be careful about using macros. I would be concerned if

Thanks for the details. If you are reading from a shared variable like that you most definitely need to be careful about using macros. I would be concerned if I wasn't using some sort of read_once routine or macro (like a sister comment also mentioned), since I have no idea what games a compiler or architecture is allowed to play without such an explicit restriction. And once I was using such a read_once to fetch that shared variable, I think it would be obvious that writing it in function argument position is a red flag to signal "be careful, if this is a macro".