Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 24 Jul 2012 11:46:25 -0700 | Subject | Re: [PATCH v2] posix_types.h: make __NFDBITS compatible with glibc definition |
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On Tue, Jul 24, 2012 at 11:32 AM, Josh Boyer <jwboyer@redhat.com> wrote: > Recent glibc made a change to suppress sign-conversion warnings from FD_SET > (glibc commit ceb9e56b3d1). That patch solved the particular error it was > aiming to, however applications that #include <linux/types.h> after > including <sys/select.h> can now hit a build failure if -Werror=sign-compare > and -D_FORTIFY_SOURCE=2 is passed to gcc. This can be seen when building > this trivial application against a recent enough glibc:
Looking more at this, I now hate it for *another* reason.
Making __NFDBITS be a signed value turns __FDELT() and __FDMASK() into potentially pure and utter crap. Doing signed divisions (or modulus) is a disaster - suddenly it's not just a bit shift any more.
Guys, the glibc people really seem to not have thought their change through. Or maybe they fixed their __FDELT/__FDMASK at the same time?
Linus
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