Re: futex(2) man page update help request

[Andy Lutomirski]

On Wed, May 14, 2014 at 5:28 PM, H. Peter Anvin <hpa@xxxxxxxxx> 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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