On Sun, 12 Jul 2020 at 22:45, Jens Maurer via SG10 <[email protected]> wrote: > > On 12/07/2020 20.05, Ben Craig via SG10 wrote: > > https://isocpp.org/files/papers/P2198R0.html > > > > While writing examples for feature-test usage in freestanding, I discovered > > how much of a pain it is to detect extensions to freestanding. The above > > paper makes that detection possible and makes policy recommendations for > > future papers. In order to fix the problem, I ended up bumping the version > > on _all_ the library feature test macros. > > > > Let me know what you think, and then we can figure out if we need an SG10 > > telecon to discuss this. > > Uh.. no. > > It seems that freestanding implementations that ship a <version> header > with those feature-test macros present that represent features not > available on their platform (e.g. std::filesystem) are actively misleading > and violating the spirit of the feature-test macros. > > If the current wording allows or requires such macros for freestanding, > the standard is buggy and needs to be DR-fixed.
libstdc++ seems to have made the feature-testing macros in <version> conditional based on hosted/freestanding at the end of last year. Ben is apparently trying to come up with a solution that allows feature-testing feature-testing, i.e. to cope with the shipping problematic implementations. -- SG10 mailing list [email protected] https://lists.isocpp.org/mailman/listinfo.cgi/sg10
