_ATFILE_SOURCE Obsoletion

[Michael Kerrisk (man-pages)]

On 18 October 2017 at 13:01, Rical Jasan <ricaljasan@pacific.net> wrote:
> On 10/18/2017 02:41 AM, Andreas Schwab wrote:
>> On Okt 18 2017, Rical Jasan <ricaljasan@pacific.net> wrote:
>>
>>> Does it really serve a useful purpose to broaden the definition of
>>> _ATFILE_SOURCE?  I understand the desire to cease support of historical
>>> artifacts, but I would rather remove support entirely than merely change
>>> the definition.  While POSIX.1-2008 may imply __USE_ATFILE,
>>> _ATFILE_SOURCE does not necessarily imply all of POSIX.1-2008.
>>
>> Is _ATFILE_SOURCE actually used in the wild in the strict sense?
>
> It is prevalent enough to make determining that an ordeal.  There are
> roughly 50 packages on https://codesearch.debian.net/ that use it.
> Whether any use it in a context that doesn't expect or requires
> _POSIX_C_SOURCE to not be at least 200809L, is practically an audit.

Given that _ATFILE_SOURCE first appeared in 2006, 2 years ahead of the
relevant POSIX.1-2008, it would not surprise me if there are still
(perhaps rare) usages in the wild in the strict sense.

Also, broadening the meaning of _ATFILE_SOURCE to imply
_POSIX_C_SOURCE==200809L sems a little risky to me, in terms of
possibly creating developer pain.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/