Subject: Re: [boost] [atomic] Probable documentation issue: how do weknowatomic is safe and/or efficient?
From: Rob Stewart (robertstewart_at_[hidden])
Date: 2013-12-25 07:40:29
On Dec 24, 2013, at 2:24 PM, Andrey Semashev <andrey.semashev_at_[hidden]> wrote:
> On Tuesday 24 December 2013 17:17:37 John Maddock wrote:
>>>> I'm sure the answer to (a) is that it is correct, but I was surprised that atomic<int> relied on the volatile modifier for thread safe load/stores on MSVC, I had assumed that something more than that would have been required, but I know I'm out of date on this stuff!
>>> "volatile" was changed in VC++ 8.0 to guarantee acquire/release semantics,
>>> then changed back in 2012 to only do so when /volatile:ms is active, which it is by default, except on ARM.
>> So does this mean that Boost.Atomic is perhaps not safe after all?
> No, it's perfectly safe on x86. It is also safe on ARM if /volatile:ms is specified.
How do you ensure the use of /volatile:ms? Can users build Boost with /volatile:iso?
(Sent from my portable computation engine)
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