[cpp-threads] Atomic operations and memory barriers

[Peter Dimov]

Nick Maclaren wrote:
> Thinking about it, I realise that there is one very fundamental
> point where there may be confusion.
>
> Let us start from the position that atomic operations do not imply
> a memory barrier.  Not a problem.  But some of the previous messages
> imply that they could move over one.  If that is permitted, it is a
> catastrophic mistake.  Yes, that bad :-(

Atomics can't move across a barrier unless ordinary operations can do so as 
well.