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    SubjectRe: futex(2) man page update help request
    On Wed, May 14, 2014 at 5:28 PM, H. Peter Anvin <hpa@zytor.com> wrote:
    > On 05/14/2014 01:56 PM, Davidlohr Bueso 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().
    >>
    >> That's actually not quite true. There are plenty of software efforts out
    >> there that use futex calls directly to implement userspace serialization
    >> mechanisms as an alternative to the bulky sysv semaphores. I worked
    >> closely with an in-memory DB project that makes heavy use of them. Not
    >> everyone can simply rely on pthreads.
    >>
    >
    > More fundamentally, futex(2), like clone(2), are things that can be
    > legitimately by user space without automatically breaking all of glibc.

    I'm lost -- I think the missing verb is important :)

    > There are some other things where that is *not* true, because glibc
    > relies on being able to mediate all accesses to a kernel facility, but
    > not here.

    --Andy


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