Hi Maciej, > Date: 2026-08-02 22:23:36+0100 > From: "Maciej W. Rozycki" <[email protected]> > > On Sun, 2 Aug 2026, Alejandro Colomar wrote: > > > The original implementation in glibc would have been con‐ > > forming to C99. However, and ironically, trying to comply > > with C99 before the standard was released, glibc changed > > its behavior in glibc 2.1.1 into something that ended up > > not conforming to the final C99 specification (but this is > > debated, as the wording of the standard seems self‐contra‐ > > dicting). > > Well, this was a period when glibc was driven by personal preferences of > one particular maintainer, so I don't think it is a good example in this > discussion.
Just to clarify something about this, to which I didn't reply before: we can't blame Drepper for this bug. In this case, there was a discussion in the mailing list, and there was no discrepancy against this change. <https://sourceware.org/pipermail/libc-alpha/1999-April/000956.html> It's just a case of a discussion that happened with incomplete information, and which favoured standards conformance over common sense. In fact, I was surprised when I learnt about this case, because I would have expected Drepper to ignore the standard for being bogus. Jonathan Larmour correctly noted in that discussion that glibc was not conforming to C89. <https://sourceware.org/pipermail/libc-alpha/1999-April/002394.html> This finding from Jonathan should have triggered some more research, but they didn't. Roland McGrath pointed out his understanding of the (ambiguous) C89 specification, and claimed that it was a bug in glibc (and thus he seems to have been in favour of the "fix" too). <https://sourceware.org/pipermail/libc-alpha/1999-April/000958.html> Interestingly, he claimed that it was a recently introduced bug, but as far as I know, the glibc behavior had been unchanged before that. It seems it was Roland McGrath who pushed for the idea that consistency wasn't paramound, and that standards conformance was. <https://sourceware.org/pipermail/libc-alpha/1999-April/002398.html> Then Drepper did that change, and in his head it was consistent. <https://sourceware.org/pipermail/libc-alpha/1999-April/000963.html> It clearly isn't consistent, but it's understandable that he didn't see it back then. Wolfram Gloger seemed to be convinced that Drepper's change was consistent (even if it isn't). <https://sourceware.org/pipermail/libc-alpha/1999-April/002401.html> For some reason, nobody in that group analyzed this carefully enough. I guess it was inertia. We can't blame Drepper (alone) for this bug. Have a lovely day! Alex -- <https://www.alejandro-colomar.es>
signature.asc
Description: PGP signature
