In particular, the “multi-threaded using volatile” example is technically incorrect because the compiler is allowed to move non-volatile accesses across volatil

In particular, the “multi-threaded using volatile” example is technically incorrect because the compiler is allowed to move non-volatile accesses across volatile ones. [1] To make it correct (but still only on x86), you’d have to use std::sync::atomic::compiler_barrier. [1] https://gcc.gnu.org/onlinedocs/gcc/Volatiles.html https://gcc.gnu.org/onlinedocs/gcc/Volatiles.html