On 4 May 2017 at 13:11, Toebs Douglass wrote: > This being true if and only if the atomic load/store functions are used, > right? and I suspect those functions are only issuing memory barriers? > they do not use atomic operations themselves. If this is so, then all > this is true, but there is within this absolutely no guarantee than any > store on any core will ever *actually be seen* by any other core. If > they *are* seen, *they will be in the correct order*, but there is no > guarantee they *will* be seen. The C++ standard says: An implementation should ensure that the last value (in modification order) assigned by an atomic or synchronization operation will become visible to all other threads in a finite period of time. "Should" in ISO-speak is strong encouragement, but not a guarantee. However, it is expected that on all but the most esoteric hardware platforms it will be true. I don't see equivalent wording in the C11 standard though.
