* The only exception is that the flag -std=c++2a is still used not to break compatibility with older compilers (clang <= 9, gcc <= 9).
* Bump _LIBCPP_STD_VER for C++20 to 20 and use 21 for the future standard (C++2b).
That's a preparation step to add c++2b support to libc++.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D93383
This simplifies the workflow for adding new feature-test macros for
contributors. Previously, they would have to move the generated <version>
header from a temporary directory to libc++'s include directory by hand.
This makes the behavior for the <version> header consistent with what's
done for the tests and the documentation.
Summary:
This patch implements all the feature test macros libc++ currently supports, as specified by the standard or cppreference prior to C++2a.
The tests and `<version>` header are generated using a script. The script contains a table of each feature test macro, the headers it should be accessible from, and its values of each dialect of C++.
When a new feature test macro is added or needed, the table should be updated and the script re-run.
Reviewers: mclow.lists, jfb, serge-sans-paille
Reviewed By: mclow.lists
Subscribers: arphaman, jfb, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D56750
llvm-svn: 351286
Marek Kurdej