On 5/15/14, 1:13, "Peter Zijlstra" <peterz@xxxxxxxxxxxxx> wrote: >On Wed, May 14, 2014 at 04:23:38PM -0400, Carlos O'Donell wrote: >> On 05/14/2014 03:03 PM, Michael Kerrisk (man-pages) wrote: >> >> However, unless I'm sorely mistaken, the larger problem is that glibc >> >> removed the futex() call entirely, so these man pages don't describe >> > >> > I don't think futex() ever was in glibc--that's by design, and >> > completely understandable: no user-space application would want to >> > directly use futex(). (BTW, I mispoke in my earlier mail when I said I >> > wanted documentation suitable for "writers of library functions" -- I >> > meant suitable for "writers of *C library*".) >> >> I fully agree with Michael here. >> >> The futex() syscall was never exposed to userspace specifically because >> it was an interface we did not want to support forever with a stable >>ABI. >> The futex() syscall is an implementation detail that is shared between >> the kernel and the writers of core runtimes for Linux. > >That ship has sailed.. for one we must always support old glibc which >uses the futex() syscall, and secondly there are known other programs >that actually use the futex syscall. > >So that's really a non-argument, we're hard tied to the ABI. Indeed. This is specifically why FUTEX_REQUEUE still exists (despite it's bugs) when only FUTEX_CMP_REQUEUE should ever be used in new programs. -- Darren Hart Open Source Technology Center darren.hart@xxxxxxxxx Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
