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Subject: Re: [SG10] A feature macro for mandatory copy elision
From: Jonathan Wakely (cxx_at_[hidden])
Date: 2017-10-09 11:12:17


On 9 October 2017 at 17:10, Nelson, Clark <clark.nelson_at_[hidden]> wrote:

> Perhaps I should also ask: should the name of the macro use the word
> "mandatory", or would "guaranteed" (as from the original document title) be
> better?
>
>
Yes, I was going to suggest "guaranteed".

> Clark
>
> > -----Original Message-----
> > From: features-bounces_at_[hidden] [mailto:features-bounces_at_open-
> > std.org] On Behalf Of Nelson, Clark
> > Sent: Monday, October 09, 2017 09:09
> > To: Richard Smith <richard_at_[hidden]>; Ville Voutilainen
> > <ville.voutilainen_at_[hidden]>
> > Cc: features_at_[hidden] <Features_at_[hidden]>
> > Subject: Re: [SG10] A feature macro for mandatory copy elision
> >
> > > After a while pondering, the best example I've got to demonstrate a
> > > need for the feature test macro is something like this:
> > >
> > > #ifdef __cpp_mandatory_copy_elision
> > >
> > > NoCopyNoMove indirectFactory() {
> > > return factory(1); // ill-formed prior to C++17
> > > }
> > > #endif
> >
> > At this point I gather that no one has an objection to providing a
> > macro for mandatory copy elision.
> >
> > Should SD-6 contain an example like this one? It seems to me that
> > there ought to be a different definition of indirectFactory under an
> > #else, but I don't know what it should look like.
> >
> > Clark
> > _______________________________________________
> > Features mailing list
> > Features_at_[hidden]
> > http://www.open-std.org/mailman/listinfo/features
> _______________________________________________
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>



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