Re: USE_LANGUAGES and wrappers

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

Joerg Sonnenberger <joerg%bec.de@localhost> writes:

> On Sun, Jul 23, 2023 at 07:14:54AM -0400, Greg Troxel wrote:
>> Greg Troxel <gdt%lexort.com@localhost> writes:
>> 
>> >   3) Adjust wrappers so that if e.g. c++17 is not in USE_CXX_FEATURES,
>> >   then any invocation with --std=c++17 will fail.
>> 
>> I believe there have been no objections to this point either.
>
> This is no different really than defaulting to some archaic old standard
> for the sake of it.

It causes a failrue when a language variant should have been declared
but wasn't.  Fixing that means that when building on a platform with a
base compiler that doens't support that standard, an adequate compiler
will be forced.

Regardless of whether we force an failure, it is an error for a package
to use c++17 if c++17 is not in USE_CXX_FEATURES.


Pleaes refrain from using words like archaic incorrectly.  That probably
applies fairly to K&R C, and might apply to c89 and c++03.  But c++11 is
merely "not up to date with rapid specification changes".