[SG10] Draft: ready for the mid-term mailing?

John Spicer jhs at edg.com
Mon Jun 24 02:19:15 CEST 2013


I have an alternate suggestion for the __cpp_lib_header_* macros.

If a library provide needs to update a header (e.g., <utility> to define something like __cpp_lib_header_optional), why don't we just require them to provide the <optional> header, and if they don't implement the feature the complete contents of the file would be:

	#define __cpp_lib_header_optional 0

John.


On Jun 21, 2013, at 8:52 PM, "Nelson, Clark" <clark.nelson at intel.com> wrote:

> Here, just in time for the weekend (in my time zone), is a draft fresh out
> of the oven.
> 
> Basically all of the substantive changes relative to what I sent out after
> Wednesday's meeting are related to __has_include, for which you can search.
> 
> In particular, since I received no responses to my last message explaining
> why I think the __cpp_lib_header_* macros are important, I have left them
> in. But I have moved them to the <utility> header (having heard no objection
> to that idea).
> 
> So there are two ways by which we recommend it be possible to test for
> these new headers. That is supposed to be clear from the way the table is
> laid out, but I'm afraid that there are too many different subtleties in
> what I've tried to imply through the table layout. I'm going to experiment
> with making the subtleties clearer by adding footnotes.
> 
> Don't forget that the deadline for the mid-term mailing is one week from
> today, so we're getting close to the wire.
> 
> --
> Clark Nelson            Vice chair, PL22.16 (ANSI C++ standard committee)
> Intel Corporation       Chair, SG10 (C++ SG for feature-testing)
> clark.nelson at intel.com  Chair, CPLEX (C SG for parallel language extensions)
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