On Thu, Sep 1, 2022, 2:33 PM Mark de Wever <koraq@xs4all.nl> wrote:
On Thu, Sep 01, 2022 at 02:14:11PM -0500, Barry Revzin wrote:
> On Thu, Sep 1, 2022, 1:30 PM Mark de Wever <koraq@xs4all.nl> wrote:
>
> > Sorry for the late reply, but I wasn't subscribed to this mailing list
> > and I wasn't aware there were proposed changes for fix the feature-test
> > macro conflicts introduced during the last plenary.
> >
> > For libc++ combining the feature-test macros for these two papers isn't
> > great:
> > P2508R1 "Expose std::basic-format-string<charT, Args...>"
> > P2419R2 "Clarify handling of encodings in localized formatting of chrono
> > types"
> >
> > P2508R1 is included in libc++15 which should ship this month. (The only
> > part I haven't implemented for that paper is the feature-test macro.)
> >
> > I have started to work on the chrono formatters in libc++ but it will
> > take some time before it will be done. Especially since libc++ still
> > misses parts of C++20 chono: timezones, leapseconds, and some clocks.
> > So it will take some time before I have a look at P2419R2.
> >
> > I propose to use two separate macros to resolve the conflicts between
> > these two papers:
> > P2508R1 __cpp_lib_format with the value 202207
> > P2419R2 __cpp_lib_format_chrono with the value 202207
> >
> > Combining the two formatting ranges papers in __cpp_lib_format_ranges
> > sounds good to me.
>
> But all the chrono formatting is already included in __cpp_lib_format (by
> way of P1361). If libc++ doesn't support that yet, you can't bump that
> macro anyway?

I had a look at P1361 before and I just looked again, but it I don't see
a feature-test macro. (I already had that on a list of notes I have for
that paper.)

Regards,
Mark

https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations#__cpp_lib_format

I don't remember when/where this was discussed, but it's there. 

Barry