[libcxx-commits] [PATCH] D96577: [libcxx] adds concept `std::uniform_random_bit_generator`

Wed Feb 17 15:44:39 PST 2021

CaseyCarter added inline comments.

================
Comment at: libcxx/include/random:1704

+#if _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+
----------------
cjdb wrote:
> cjdb wrote:
> > ldionne wrote:
> > > miscco wrote:
> > > > in https://reviews.llvm.org/D93166 we have a definition of _LIBCPP_HAS_NO_CONCEPTS
> > > > 
> > > > Should we reuse that globally and why are there different values ofr the macro?
> > > > why are there different values ofr the macro?
> > > 
> > > I don't know. @cjdb do you know what `201907L` vs `201811L` represents for `__cpp_concepts`?
> > > 
> > > > Should we reuse that globally 
> > > 
> > > Depending to the answer to the question above, I think it would make sense to use `#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)`.
> > I believe @Mordante has a patch to fix this globally. As for 201811L vs 201907L, this is consistent with what's in libc++ `<concepts>` right now.
> @saar.raz do you know the difference between these two values for `__cpp_concepts`?
https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations#__cpp_concepts explains the history fairly well.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96577/new/

https://reviews.llvm.org/D96577