[libcxx-commits] [PATCH] D138195: [libc++] Fix __regex_word value when using newlib/picolibc

[Alexander Richardson via Phabricator via libcxx-commits]

arichardson added a comment.

In D138195#3937471 <https://reviews.llvm.org/D138195#3937471>, @philnik wrote:

> In D138195#3937400 <https://reviews.llvm.org/D138195#3937400>, @michaelplatings wrote:
>
>> I think this could be considered an ABI break. I don't see an alternative and given that the static assert has been failing for some time maybe no-one cares. But just in case, would it be worth noting in the release notes <https://github.com/llvm/llvm-project/blob/main/libcxx/docs/ReleaseNotes.rst#abi-affecting-changes>?
>
> This is definitely an ABI break, but I'm not sure we care for newlib about that. We don't officially support it and most people that are using newlib + libc++ are probably in an environment where ABI stability isn't much of a concern. It's mostly used in embedded environments, right? It's probably a good idea to add a note to the `ABI Affecting Changes` section though.

I agree this is technically an ABI break, but I believe there can't be any affected code since the static_assert would have failed previously when including <regex> for a libc++ build with locale support? And even if it is, I would assume this should not matter for newlib where you generally don't have a system libc++.so that is being linked against.
Happy to add a release note though.


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https://reviews.llvm.org/D138195