[Development] Proposing to officially allow C++20 types in Qt 6 ABIs

[Thiago Macieira]

On Thursday, 27 January 2022 11:54:37 PST Marc Mutz wrote:
> Hi Thiago,
> 
> > So here's my counter-proposal:
> > 
> > We allow C++17 and C++20 Standard Library types in our ABI provided:
> > * we update our builds, all of them, to build with C++20 by default
> > * the use of those symbols in the ABI is NOT behind an #if __cpp_lib check
> 
> This limits our ABI on _all_ platforms to the lowest common denominator
> _across_ platforms. That is precisely what we want to change: we want to be
> able to provide ABI that uses std::span and coroutines _without_ having to
> wait for Integrity, QNX, and Apple to get their act together.

I think it's fine to make the check per OS. But we can't use the __cpp_lib 
variables.

Incidentally, please don't make people who have no access to those toolchains 
have to comply with them. Only people who have a commercial interested should 
be required to suffer them.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel DPG Cloud Engineering