Re: [boost] _ReadWriteBarrier as memory fence, or not?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2008-08-21 21:35:38

Simon Thornington:
> Hi folks,
>
> Quick question about the use of _ReadWriteBarrier (Win32 MSVC):
>
> According to http://msdn.microsoft.com/en-us/library/ms684208(VS.85).aspx 
> ,
> this compiler intrinsic doesn't generate any memory fencing instructions 
> at
> all, it's strictly a compiler optimization barrier.  I was wondering if
> someone had any documentation to contradict this, or if boost is relying 
> on
> the new volatile semantics in VC2005 to ensure the fence?
>
> It sure looks like it's being used as if it were a real memory fence, but 
> I
> am not sure that's the case.  I'm not an expert though.

What specific _ReadWriteBarrier use do you find suspicious?