On Wed, May 14, 2014 at 1:23 PM, Carlos O'Donell <carlos@xxxxxxxxxx> 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. > > The fact that the futex() syscall is out of date is my fault, is the fault > of Linux kernel developers, etc. etc., we should all have reached out to > Michael with patches to keep this developer-centric documentation updated. I realize that this is out of scope for linux-abi, but I *stongly* disagree with this notion. futex() needs to be just as stable as anything else: old glibc versions must continue to work. I just jumped through a bunch of hoops to keep a single glibc patch release in OpenSUSE 9 working in a maintainable way; breaking futex will break far more than that. Additionally, at least the FUTEX_WAIT and FUTEX_WAKE operations are extremely useful, and they can do things that are tedious at best using mutexes and condvars. It's a simple API to use. I use it, and I've seen plenty of other open-source apps using the futex API directly. I think the best way forward might be to try to convince the glibc maintainers to add the wrapper. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
