add a warning about using safe on extern c-variadic functions
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safesafe on extern c-variadic functions
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Let's adjust this language so that it talks about the guarantees that the function must make, and so that it says what may lead to UB rather than what "is" UB, as the latter implies immediate language UB, when this is actually library UB. Let's also add a `SAFETY` comment to the function in the example.
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traviscross
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Jun 4, 2025
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Thanks for the PR. Pushed an update to revise a bit, to add a |
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edit: the lang team found an edge case.
An extern c-variadic function can be marked as safe when it does not look at its arguments at all. That is not very useful, but technically allowed.
So, I've now added a warning with this information to the section on extern c-variadic functions.