[cfe-dev] [libcxx] Policy with respect to language extensions

[Hal Finkel]

----- Original Message -----
> From: "Marshall Clow" <mclow.lists at gmail.com>
> To: "David Majnemer" <david.majnemer at gmail.com>
> Cc: "Richard Smith" <richard at metafoo.co.uk>, "clang developer list" <cfe-dev at lists.llvm.org>, "Gonzalo BG"
> <gonzalobg88 at gmail.com>
> Sent: Wednesday, August 12, 2015 5:05:05 PM
> Subject: Re: [cfe-dev] [libcxx] Policy with respect to language extensions
> 
> On Wed, Aug 12, 2015 at 11:32 AM, David Majnemer <
> david.majnemer at gmail.com > wrote:
> 
> 
> On Wed, Aug 12, 2015 at 2:05 PM, Richard Smith <
> richard at metafoo.co.uk > wrote:
> 
> 
> 
> I think it would also be useful to have a "strictly conforming" (or
> as close as we can reasonably get) mode, controlled by a macro.
> 
> 
> Wouldn't we have to be extra careful or we could get ODR violations
> across object/shared object boundaries if one wanted extra
> conformance but another did not?
> 
> Yes.
> 
> 
> -- Marshall

Having a macro to control this seems like a recipe for bad things (ODR violation being only one problem).

I think the best we can do at this point is have the compiler issue a warning in pedantic mode. Maybe we could add some kind of extension attribute for this purpose (although we'd need to think carefully about when to actually generate the warning - every time some extension participates in some overload set might be problematic).

 -Hal

> 
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory