Re: [RFC v1] man/man2/close.2: CAVEATS: Document divergence from POSIX.1-2024

[Al Viro <viro@zeniv.linux.org.uk>]

On Tue, Jan 20, 2026 at 11:36:34AM -0500, Rich Felker wrote:
> On Tue, Jan 20, 2026 at 11:15:15AM -0500, Zack Weinberg wrote:
> > Rich and I have an irreconciliable disagreement on what the semantics of close
> > _should_ be.  I'm not going to do any more work on this until/unless he
> > changes his mind.
> 
> It's been way too long since I read this thread to recall what our
> point of disagreement is or what point glibc might be at in
> reconciling the Linux kernel disagreement with POSIX.

It's not so much disagreement as breakage of internal POSIX decision
process that has lead to POSIX irrelevance in this particular area.

POSIX authority derives from the agreement of actual behaviour of
Unices.  Always had been, witness the amount of underspecified
areas where various vendor implementation had different semantics,
due to exact that reason.

They (or anybody else, really) can argue that such-and-such behaviour
ought to change.  In quite a few cases that has succeeded.  What they
can't do is to force such change by fiat.  Especially not when Linux
and *BSD happen to agree on behaviour that differs from what they
wish it to be.