[Bug c++/93821] Define __cplusplus to 202002L in C++20

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.0                        |10.2

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.1 has been released.

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.2                        |10.3

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.2 is released, adjusting target milestone.

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[romain.geissler at amadeus dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

Romain Geissler <romain.geissler at amadeus dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #7 from Romain Geissler <romain.geissler at amadeus dot com> ---
Hi,

This was implemented in gcc 11 with this commit:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;f=libcpp/init.c;h=445430e16bd08ade34637d2346ded40dd49de508

Closing.

Cheers,
Romain

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[mail at 3v1n0 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

Marco Trevisan <mail at 3v1n0 dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mail at 3v1n0 dot net

--- Comment #8 from Marco Trevisan <mail at 3v1n0 dot net> ---
Is this released on any gcc 10 point release version (as per debian stable
support)?

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No. C++20 support in GCC 10 is missing a number of features, so it would be
misleading/incorrect to define it to 202002L.
https://gcc.gnu.org/projects/cxx-status.html#cxx20

You can just test for > 201703L if you want to know if partial C++20 support is
present. Or use the feature test macros for individual features.

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[mail at 3v1n0 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

--- Comment #10 from Marco Trevisan <mail at 3v1n0 dot net> ---
I see the point, but then I also think that gcc-10 should not support
`--std=c++20` option but rather only the `--std=c++2a` one.

[Bug c++/93821] Define __cplusplus to 202002L in C++20

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93821

--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No, because that just makes it more awkward to write makefiles and build
scripts. We used to do that, and it had no real benefit. If you want to use
c++2a, you can use that. Other people just want to use c++20 across multiple
releases, some of which have full C++20 support and some don't.

To check the level of conformance you should check the macros defined by the
compiler when compiling, not rely on which command-line options happen to be
supported.