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Date: Mon, 19 Oct 2020 14:01:27 +0200
From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: stat st_birthtim(espec)
Message-ID: <20201019120127.GG5492@calimero.vinschen.de>
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On Oct 19 02:06, Phil Budne wrote:
> While checking if an OSS project of mine (www.snobol4.org/csnobol4)
> compiled cleanly under Cygwin, I was happy to discover that struct
> stat contains file birth time as on various BSD based systems.
> 
> BUT, I was unhappy to find out that MacOS 10.15 and Cygwin 3.1.7 have
> non-overlapping definitions for birth time information.
> 
> FreeBSD 12, NetBSD 9, and OSX 10.15 all have a "timespec" available as
> "st_birthtimespec", but Cygwin does not.
> 
> On FreeBSD, NetBSD, and Cygwin the actual member of struct stat is
> st_birthtim, but on OSX, the member is st_birthtimespec, and there is
> no define for st_birthtim.
> 
> A st_birthtimespec define in cygwin/stat.h would make it easier to
> write portable code.

Well, portable code should use the st_atim/st_mtim/st_ctim members
directly and not use st_birthtim at all.

For the headers we're usually looking for Linux compatibility in the
first place and if that's any indication, we should add all the
st_XYZtimensec members, but *only* if __USE_XOPEN2K8 is defined
(equivalent _XOPEN_SOURCE >= 700 for Cygwin/newlib)

GLibc does not provide any st_XYZtimespec definitions, though.  I don't
think it really makes a lot of sense to add those with portability in
mind.


Corinna
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