> In Rust it's not even possible to write such code.
What does "such code" mean though? Rust won't let you say that your mutable variables are just shared between threads, because that's unsafe. But if you say OK, I want atomic data types (and so they lack tearing and other things you were bothered about) then you can clone an Arc of them, and write code to manipulate the atomics whose consequences are just as under specified. It's just that now you have to spell out that this is what you wanted, writing e.g. std::sync::atomic::Ordering::Relaxed
If you later complain to me that this code surprised you because the memory ordering wasn't what you expected, I will point at that symbol. If you wanted some specific ordering then "Relaxed" was wrong.
> My point is that the assumption that a == b is invalid if x is a global variable.
No it isn't? This is an important optimisation, which you would prefer to sacrifice rather than just writing what you mean in the first place.
> if you've any relevant references / descriptions of their memory model, let me know!
Sure, however now your atomic has 'static lifetime so it lives forever and that's sort of cheating. The reference counter means nobody in particular needs to be in charge of cleaning up, whoever has it last will drop it. Call it personal preference.
Also, is the broken kinda of look of your blog an aesthetic choice or a bug? Is "
What does "such code" mean though? Rust won't let you say that your mutable variables are just shared between threads, because that's unsafe. But if you say OK, I want atomic data types (and so they lack tearing and other things you were bothered about) then you can clone an Arc of them, and write code to manipulate the atomics whose consequences are just as under specified. It's just that now you have to spell out that this is what you wanted, writing e.g. std::sync::atomic::Ordering::Relaxed
If you later complain to me that this code surprised you because the memory ordering wasn't what you expected, I will point at that symbol. If you wanted some specific ordering then "Relaxed" was wrong.
> My point is that the assumption that a == b is invalid if x is a global variable.
No it isn't? This is an important optimisation, which you would prefer to sacrifice rather than just writing what you mean in the first place.
> if you've any relevant references / descriptions of their memory model, let me know!
https://kcsrk.info/papers/pldi18-memory.pdf