Re: Implement C11 _Atomic

[Andrew MacLeod <amacleod@redhat.com>]

On 11/21/2013 11:32 AM, Joseph S. Myers wrote:
> On Thu, 21 Nov 2013, Andrew MacLeod wrote:
>
>>> I'm trying to avoid ABI breakage of course.  I'd rather not have
>>> to ask people not to use _Atomic with 4.9 for CRIS ports using
>>> official releases or have ABI breakage with the next release.
>>> Maybe there's one other port in the same situation...
>> None I am aware of, but that doesn't mean much :-)
> It has been suggested that hppa may have interesting issues for atomics -
> but I'd think atomics support for it in GCC would mainly be for GNU/Linux,
> where you have kernel helpers that may avoid the issues with the
> underlying architecture.
>
> Note that if you want libstdc++ atomics to be ABI compatible with C
> atomics then there may be more work to do on that side (again, there are
> pieces on the branch).
>
I was just about to point out that  :-)    that would be a 
shortcoming... 4.9 C++11 atomics do not use the same mechanism yet, so 
they would still behave the same as 4.8 C++ atomics, even with the 
override present.... C11 _Atomic variables would be the only beneficiary 
at this point of the override.

Andrew