g++ 12 -std=gnu++20

[Brian Inglis]

On 2024-11-02 16:49, ASSI via Cygwin wrote:
> Dimitry Andric via Cygwin writes:
>> I think most Linux distributions have switched fully to the new ABI by
>> now, and dropped support for the old ABI, so they configure their
>> gcc's with _GLIBCXX_USE_CXX11_ABI=1 by default.

I struggled to find any Cygwin or online docs mentioning this, until the poster 
linked:

	https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html,

when I realised there are docs provided only for gcc/g++, objc/objc++, gccint, 
gfortran, libgccjit, libgomp, libquadmath, but nothing for libstdc++, not even 
info or man pages.

Is there any chance we could possibly get libstdc++.info* or man pages included 
with the build, or as (a) separate -doc package(s), and possibly other libraries 
or components where info or man pages are available, and may not currently be 
built or installed?

 > They also have the luxury of full distro rebuilds every once in a while.
 >
 > I wouldn't mind getting rid of this historical wart with the switch to
 > gcc-13 sometime next year if someone can convince me that the existing
 > packages (many of which have no current maintainer and therefore will
 > not be easily rebuilt) keep working.  In particular, Qt5 should still be
 > linkable and function with packages built before and after the switch.

Given that cygwin/-devel is likely built with the old ABI, is there any point in 
trying to build libraries/packages that *require* the new ABI features in C++20?

I am asking to adopt dependent orphaned packages, just so I *can* rebuild them 
with the new ABI, so is trying this exercise going to be futile?

One upstream refuses to support distros that do not support C++20 compilers,
so curl and wget2 will hopefully continue to build with their current package!

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry