Re: C++20 and gcc12/10

[David Holland <dholland-pkgtech%netbsd.org@localhost>]

On Wed, Apr 16, 2025 at 07:45:31PM -0400, Greg Troxel wrote:
 > Further, I think for semantic sanity, c++14 should mean "really the
 > whole language", but c++14-base/c++14 vs c++14/c++14-full is somewhat a
 > paint color.   Using c++14 for "whole language" is also preferable for
 > when "less than c++14" becomes irrelevant.

Right, the default case is "package docs say c++14, put c++14 in the
makefile" and any arrangement that leads to this not working unless
you know you also need to add "c++14-ftagn" as well will lead to lots
of cursing and shouting.

 > I think we can do this operationally, understanding that we have and
 > will have rough edges about our understanding of the world, to be fixed
 > up as needed:
 > 
 >   c++20-base: the part of the language that gcc10 copes with
 > 
 >   c++20: the full language (that you need gcc12 for)

Right, except I think it should just be c++20-gcc10 unless and until
there's any evidence any further detail is needed or wanted. There
hasn't been any so far.


 > (This is all orthogonal to the "building with multiple compilers
 > considered harmful" discusion.  I ~always want to keep separate things
 > separate anyway.)

Right, except that if we do this we might be able to kick that one
down the road again. Which is at least slightly preferable in the near
term because any real solution to that problem is going to be fairly
involved.

(but in the long term it's better to fix it properly...)

-- 
David A. Holland
dholland%netbsd.org@localhost