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Subject: Re: P2198R0, more feature-test poking from freestanding
From: Jens Maurer (Jens.Maurer_at_[hidden])
Date: 2020-07-12 14:45:16


On 12/07/2020 20.05, Ben Craig via SG10 wrote:
> https://isocpp.org/files/papers/P2198R0.html
>
> While writing examples for feature-test usage in freestanding, I discovered how much of a pain it is to detect extensions to freestanding.  The above paper makes that detection possible and makes policy recommendations for future papers.  In order to fix the problem, I ended up bumping the version on _all_ the library feature test macros.
>
> Let me know what you think, and then we can figure out if we need an SG10 telecon to discuss this.

Uh.. no.

It seems that freestanding implementations that ship a <version> header
with those feature-test macros present that represent features not
available on their platform (e.g. std::filesystem) are actively misleading
and violating the spirit of the feature-test macros.

If the current wording allows or requires such macros for freestanding,
the standard is buggy and needs to be DR-fixed.

Jens


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