[boost] Re: shared_ptr on ppc?

From: Miro Jurisic (macdev_at_[hidden])
Date: 2005-04-07 17:07:42

In article <00f901c53bb6$5caf34c0$6501a8c0_at_pdimov2>,
 "Peter Dimov" <pdimov_at_[hidden]> wrote:

> The documentation at the link above does not seem to describe memory 
> synchronization. It only says that the operations are performed atomically.
> 
> The OSAtomicAdd/Increment/Decrement implementation in OSAtomic.s does not 
> contain any sync or isync barriers. We need a decrement that is at least a 
> release when the new value is nonzero and an acquire when the new value is 
> zero.
> 
> OSCompareAndSwap (or its alias hw_compare_and_store in hw_lock.s) seems to 
> provide acquire semantics on success (it has a trailing isync). This is also 
> not mentioned in the documentation above.

Thanks. I understand the question better now. I am going to get you and 
Alexander in touch with someone who can answer your questions better than that 
web page or I can. 

meeroh