Re: Early POSIX versions seldom included in history sections

[Alejandro Colomar <alx@kernel.org>]

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Hi Seth,

On Tue, Dec 23, 2025 at 03:56:23AM +0000, Seth McDonald wrote:
> > > SUSv2.
> > > POSIX.1-2001 (XSI).
> > > POSIX.1-2008.
> 
> I do believe the standards(7) man page does describe these standards,
> including XSI. From the POSIX.1-2001/SUSv3 section:
> 
> 'The standard defines two levels of conformance: POSIX conformance,
> which is a baseline set of interfaces required of a conforming system;
> and XSI Conformance, which additionally mandates a set of interfaces
> (the "XSI extension") which are only optional for POSIX conformance.
> XSI-conformant systems can be branded UNIX 03.'
> 
> That said, I can certainly understand how just listing a bunch of
> acronyms and numbers (SUSv2, POSIX.1-2001 XSI, POSIX.1-2008) would be
> confusing for many not familiar with these standards. I can briefly
> describe such a function's progression through the standards with a
> short paragraph, if that would help. Using the function fchdir(2) as an
> example, let me know how this sounds:
> 
> HISTORY
>        fchdir()
>               SUSv1, POSIX.1-2001.

I'd make this

		SUSv1, POSIX.1-2001 XSI, POSIX.1-2008.

> 
>    SUSv1
>        fchdir(2)  was first introduced in SUSv1.  The function was then
>        included in POSIX.1-2001, but as an XSI extension.   Finally  in
>        POSIX.1-2008, it was moved to the base specification.

I tend to dislike paragraphs.  This would be interesting for the commit
message.  As you say, all of these names are documented in standards(7),
and I think the above should be readable once you know standards(7).

> 
> By the way, I too find these documents confusing as hell! I only have a
> grasp of them because I happened study them due to a recent
> hyperfixation on portable standards (my autism be like). So I certainly
> get where you're coming from here. I just don't know how much more I can
> describe in the added paragraph before intruding on the job of the
> standards(7) man page.

Agree!  It took me some years to know the standards' history (and
I still have some gaps in the older ones).  :)


Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es>

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