Re: futex(2) man page update help request

From: Peter Zijlstra <peterz@infradead.org>
To: "Carlos O'Donell" <carlos@redhat.com>
Cc: mtk.manpages@gmail.com, Darren Hart <dvhart@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	Jakub Jelinek <jakub@redhat.com>,
	"linux-man@vger.kernel.org" <linux-man@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Davidlohr Bueso <davidlohr.bueso@hp.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	Linux API <linux-api@vger.kernel.org>
Subject: Re: futex(2) man page update help request
Date: Thu, 15 May 2014 10:13:57 +0200	[thread overview]
Message-ID: <20140515081357.GC11096@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <5373D0CA.2050204@redhat.com>

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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.

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