Re: [boost] [interprocess] atomic_write32 on GCC/x86/x68_64 lacks memory barrier

Subject: Re: [boost] [interprocess] atomic_write32 on GCC/x86/x68_64 lacks memory barrier
From: Lars Hagström (lars_at_[hidden])
Date: 2014-08-11 10:53:08

Thanks very much for your help! I've learnt a lot today :-)

On Mon, Aug 11, 2014 at 4:17 PM, Peter Dimov <lists_at_[hidden]> wrote:

> Lars Hagström wrote:
>
>> Does that "memory" statement at the end add a fence both before and after
>> the assembly statement?
>>
>
> Effectively. To be more precise, it turns the assembly statement into a
> compiler fence. "memory" tells the compiler to assume that the assembly
> code accesses and modifies memory in unpredictable ways, and the effect of
> that is basically a compiler fence.
>
> You should probably use the __asm__ and __volatile__ spellings as a matter
> of style though.
>
> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/
> mailman/listinfo.cgi/boost
>