Re: 2026Q1 and USE_CXX_FEATURES+=c++20

[Greg Troxel <gdt%lexort.com@localhost>]

Edgar Fuß <ef%math.uni-bonn.de@localhost> writes:

> EF> compiler/gcc.mk says:
> EF> # gcc documents that 11 is required, with a few perhaps-obscure
> EF> # features requiring 12.  gcc10 does not define __cplusplus as meeting
> EF> # c++20.
>
> gdt> If you think that isn't accurate, please cite upstream docs.
> I wasn't questioning that, I just wanted to illustrate why 
> USE_CXX_FEATURES+=c++20 inflicts gcc12 on me.

OK, but that's "not a bug".

>> Our unwillingness to slice a standard into dozens of parts and expend
>> lots of effort to validate which gcc versions support which subsets
>> and try to avoid requiring new gcc.

> Given most upstreams will probably respond "update to trixie!" or 
> "why don't you use our docker container?", what would help is something 
> like USE_CXX_FEATURES+= formally-c++12-but-c++17-from-gcc10-works.
> Of course no-one will want to go down that rabbit hole, so I'll continue 
> to patch locally.

Indeed, nobody does!
But "update to NetBSD 11" should reduce your pain level.