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Re: __ASSUME_PRIVATE_FUTEX and __ASSUME_FUTEX_CLOCK_REALTIME
- From: Torvald Riegel <triegel at redhat dot com>
- To: Roland McGrath <roland at hack dot frob dot com>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, libc-alpha at sourceware dot org
- Date: Mon, 05 Jan 2015 20:29:01 +0100
- Subject: Re: __ASSUME_PRIVATE_FUTEX and __ASSUME_FUTEX_CLOCK_REALTIME
- Authentication-results: sourceware.org; auth=none
- References: <Pine dot LNX dot 4 dot 64 dot 1406202013520 dot 1155 at digraph dot polyomino dot org dot uk> <20140620231516 dot 6C7AA2C39C2 at topped-with-meat dot com>
On Fri, 2014-06-20 at 16:15 -0700, Roland McGrath wrote:
> > __ASSUME_PRIVATE_FUTEX and __ASSUME_FUTEX_CLOCK_REALTIME are defined for
> > all supported Linux kernel versions. Should we say they are a required
> > part of the futex interface for any system, whether or not using the Linux
> > kernel, that may wish to use NPTL, and so remove these macros and all
> > conditionals testing them everywhere in glibc, not just in
> > sysdeps/unix/sysv/linux/ files?
>
> Please, no. Other systems that provide a futex layer may well provide a
> much less fully featureful one than Linux has.
Roland, do you see any reason why having __ASSUME_FUTEX_CLOCK_REALTIME
or not couldn't be contained in the internal futex abstraction layer?
That is, we could have a futex_timed_wait that just does the right thing
on Linux, and does something different but conforming on non-Linux?
This might be similar for __ASSUME_PRIVATE_FUTEX, but I haven't looked
at this closely.
Thoughts?