Subj : Re: posix and lock-free algorithms
To   : comp.programming.threads
From : David Schwartz
Date : Sun Jul 31 2005 02:50 pm


"John Doug Reynolds" <smspiff@fastmail.fm> wrote in message 
news:1122829815.237744.74450@o13g2000cwo.googlegroups.com...

> I get the idea that the issue is that Posix does not provide explicit
> memory barriers.  If so, then there must be some reason why this
> construct does not do the trick:
>
> void memory_barrier() { mutex m; m.lock(); m.unlock(); }

    Mutexes only protect memory access that occur while the mutex is held. 
In principle, that could be optimized by a sufficiently smart implementation 
to nothing.

    DS

.