On Sat, Jul 05 2025, Alejandro Colomar <a...@kernel.org> wrote: > On top of that, I have a question about the functions I'm adding, > and the existing kernel snprintf(3): The standard snprintf(3) > can fail (return -1), but the kernel one doesn't seem to return <0 ever. > Should I assume that snprintf(3) doesn't fail here?
Yes. Just because the standard says it may return an error, as a QoI thing the kernel's implementation never fails. That also means that we do not ever do memory allocation or similar in the guts of vsnsprintf (that would anyway be a mine field of locking bugs). If we hit some invalid or unsupported format specifier (i.e. a bug in the caller), we return early, but still report what we wrote until hitting that. Rasmus
