Optimization of conditional access to globals: thread-unsafe?

[Eric Botcazou]

> And because your next question will be "how the compiler will know the
> corresponding mutex", the answer is: it can't, that's why "opaque
> function" rules come to play.

Right, so please define more or less formally what the "final value" is from 
the viewpoint of the current thread, this is the crux of the matter.

-- 
Eric Botcazou