Further clarification on volatile

[mnemnion]

@biosbob

i’m sticking with volatile…

This will work, today. It might also continue to work.

Just please bear in mind that Zig isn’t C, and isn’t beholden to C’s semantics. If I had to bet on it, I’d say that for what you’re specifically up to here, volatile will continue to do what you expect. There are some unanswered questions in the thread I linked to, but your application does fall into

If a given load or store should have side effects, such as Memory Mapped Input/Output (MMIO), use volatile.

As the documentation puts it, so it should be fine. Just be aware that it’s an under-specified corner of the language.

@LucasSantos91

I believe it is correct. In C, this would be correct, and I think Zig just inherited volatile from C. Zig has no way of knowing if a memory address is MMIO or just a normal address, so if it would work for MMIO, it has to work for this use case.

I asked some very specific questions about exactly that, which went unanswered. I think you have a correct explanation of volatile’s current behavior, and a reasonable guess as to its intended future behavior. It would be nice to get some ‘further clarification on volatile’, though.