Date: Sat, 27 Feb 2016 14:59:59 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-standards@FreeBSD.org Subject: [Bug 207544] mbtowc(3) fails to set errno(2) for incomplete characters Message-ID: <bug-207544-15@https.bugs.freebsd.org/bugzilla/>
index | next in thread | raw e-mail
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=207544 Bug ID: 207544 Summary: mbtowc(3) fails to set errno(2) for incomplete characters Product: Base System Version: 11.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: standards Assignee: freebsd-standards@FreeBSD.org Reporter: schwarze@usta.de Created attachment 167481 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=167481&action=edit patch against lib/libc/locale/mbtowc.c to fix errno handling If an incomplete character is passed to mbtowc(3), it fails to set errno to EILSEQ, even though that is unambiguously required by POSIX. Setting errno in that case makes a lot of sense because having a function that can fail and that sets errno in some failure modes but does not set errno in other failure modes would be a terrible idea. Such a function would be ridiculously complicated to use. To detect the reason for failure, you would have to: - save errno - reset errno to zero - call the function - inspect the return value to detect failure - inspect errno to decide about the reason for failure - if errno is zero, restore the saved errno That is completely unreasonable, in particular for a seemingly innocous function like mbtowc(3). Next to no programmer would get that right in any real-world program. Note that this bug is very widespread, it also affects Solaris 11 and glibc, and also OpenBSD until i fixed it today. I will also send a note around to the other systems. The OpenBSD commit will soon show up here: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/locale/mbtowc.c The attachment contains a patch against FreeBSD-current, mainly to make it even clearer what exactly i mean. Note that i did not test the patch since i don't have a FreeBSD system - so please test before commit! Thanks. -- You are receiving this mail because: You are the assignee for the bug.home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-207544-15>