Date: Sat, 30 Jul 2016 23:10:55 +0300 From: Andrey Chernov <ache@freebsd.org> To: Bruce Evans <brde@optusnet.com.au> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r303530 - head/lib/libc/gen Message-ID: <71b31670-244e-73e1-2092-4c4de5b8a692@freebsd.org> In-Reply-To: <20160730184454.I2661@besplex.bde.org> References: <201607300209.u6U29BXC082700@repo.freebsd.org> <20160730140305.G1962@besplex.bde.org> <84c77b80-8b51-8698-f27a-7f6452867d66@freebsd.org> <20160730184454.I2661@besplex.bde.org>
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On 30.07.2016 11:52, Bruce Evans wrote: > On Sat, 30 Jul 2016, Andrey Chernov wrote: > >> On 30.07.2016 7:15, Bruce Evans wrote: >>> On Sat, 30 Jul 2016, Andrey A. Chernov wrote: >>> >>>> Log: >>>> Reset errno for readdirfunc() before contunue. >>> >>> In C99, library functions are not permitted to set errno to 0. The >>> glob() >>> family shouldn't use a different (worse) convention, and POSIX doesn't >>> seem to have any special wording to allow different behaviour. BTW, POSIX says so too: "No function in this volume of POSIX.1-2008 shall set errno to 0." >> This is historic practice for this function at least since GLOB_LIMIT >> was introduced (in 2001) and common across NetBSD/OpenBSD. Existent >> programs may relay on that to check that limit is reached and not >> allocation error, so with few additional overwriting from my side I add >> nothing new: >> >> Revision 80525 >> Modified Sun Jul 29 00:52:37 2001 UTC (15 years ago) by mikeh >> ... >> errno = 0 is documented. See glob(3), GLOB_NOSPACE section too. > > Hmm. This is not in the BUGS section. Strangely, the related non-bug > that glob() may fail and set errno (to a reasonable but nonstandard and > undocumented value?) is in the BUGS section. I guess this is a bug > in conjunction with the promise to set errno to 0 for some failures. > >> The real problem is that glob(3) is very limited in error return codes, >> so they reuse existent codes with errno hack. > > It should have just used the least-unclosely-related standard errno > instead of 0. I was thinking about this way too, f.e. E2BIG or ERANGE are nice candidatures, but still can't decide to break cross-BSD compatibility and historic practice.
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