From: Stefan Puiu <stefan.puiu@gmail.com>
To: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Guillem Jover <guillem@hadrons.org>,
Andrew Clayton <andrew@digital-domain.net>,
linux-man@vger.kernel.org,
Michael Kerrisk <mtk.manpages@gmail.com>,
Alejandro Colomar <alx@kernel.org>,
Brian Inglis <Brian.Inglis@systematicsw.ab.ca>,
Rich Felker <dalias@libc.org>,
musl@lists.openwall.com
Subject: [musl] Re: [PATCH] memmem.3: Added list of known systems where this is available
Date: Thu, 24 Nov 2022 20:57:02 +0200 [thread overview]
Message-ID: <CACKs7VCNh=bxV8waEPc=Gzps+0Q3xYgrX-LbB-1LBOTzdc_9eg@mail.gmail.com> (raw)
In-Reply-To: <50485f46-99d0-69ee-0882-7e403334080c@gmail.com>
Hi,
On Wed, Nov 23, 2022 at 3:16 PM Alejandro Colomar
<alx.manpages@gmail.com> wrote:
>
> Hi all!
>
[... snipped ...]
> >
> > Not sure if it's the job of Linux man-pages to document when other
> > OSes started supporting certain APIs. That info has to be maintained,
> > updated etc. People can always read the man pages of other systems,
> > right? Maybe it's worth only pointing out when an interface is
> > Linux-only, or the Linux implementation diverges significantly.
>
> The good thing is that in most cases, it's either something in POSIX (for which
> I gon't care at all if Apple Libc or another-weirdo-libc decide to not support
> it), or it's a Linux-only function.
>
> So, there are few functions or syscalls that are generally available but are not
> in POSIX, and it might be interesting to document that they're effectively as
> portable as anything POSIX. Maybe even POSIX editors read this and decide to
> add it.
>
> In those cases, we still need to decide what we care about or not.
Aah OK, so memmem is non-standard, there is no standard to point to.
Do other OSes provide this kind of info? I don't see anything about
portability in the OpenBSD man page (https://man.openbsd.org/memmem),
only "memmem() is a GNU extension". The FreeBSD man page
(https://www.freebsd.org/cgi/man.cgi?query=memmem&manpath=FreeBSD+13.1-RELEASE+and+Ports)
does mention Linux, but only to mention that memmem was broken in old
versions of Linux libc (nothing about current Linux); it also has the
'GNU extension' mention. Interestingly, I don't see the mention of the
function being a GNU extension in the Linux version.
Have you checked, are there many such functions? Do you plan to add
this info for all of them?
>
> Musl libc is definitely a first-class citizen these days in Linux distributions.
> I would start documenting them in the project at large if someone from musl
> provides patches (I discussed this some time ago, but can't remember with who).
> Rich, if you would like to discuss about this, we can have some chat.
>
> >
> > For musl and other libcs, I think the man pages already document some
> > instances where their behavior diverges from glibc.
>
> As said, for musl, I'd document them officially, if there's anyone interested
> enough to send patches.
>
> For other libcs, we have to decide if they're important enough, and probably
> decide on a case-by-case basis.
>
> Michael tried to have some decent coverage of non-GNU/Linux systems, both in the
> man-pages and in his TLPI book. It's a useful thing. So much that sometimes
> you don't even need to read other systems' pages at all to know how portable is
> a GNU/Linux function.
I know. But not sure how much Linux docs should cover about other
OSes, which are also constantly changing (and have their own fine
docs).
As always, just my 2c,
Stefan.
>
> So, I'd like to get opinions on interest about documenting details about:
>
> - newlib (I never heard about it before; is it a widespread thing? do you think
> it's useful?)
> - Apple Libc (I still don't like it, but I must admit that it's relevant, and
> being open source, it's more palatable)
> - bionic (does anyone know if that's useful at all for anyone at all?)
>
> Support for those wouldn't go as far as musl or glibc. For now it would only be
> for memmem(3).
>
>
> Cheers,
>
> Alex
>
> --
> <http://www.alejandro-colomar.es/>
next prev parent reply other threads:[~2022-11-24 18:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20221110001318.10696-1-andrew@digital-domain.net>
[not found] ` <853fa349-8e78-8ce8-f76f-79b4b9353913@gmail.com>
[not found] ` <Y31XOPOsB932l0cd@thunder.hadrons.org>
[not found] ` <CACKs7VAQsxDc2XrsAYSEbA9eqRnLHuXykVmNTit+tCFMyGLCwA@mail.gmail.com>
2022-11-23 13:16 ` Alejandro Colomar
2022-11-23 14:55 ` Jeffrey Walton
2022-11-23 15:11 ` Alejandro Colomar
2022-11-23 15:33 ` [musl] " Shiz
2022-11-30 19:39 ` enh
2022-12-09 20:25 ` Alejandro Colomar
2022-11-24 18:57 ` Stefan Puiu [this message]
2022-12-11 16:30 ` [musl] " Alejandro Colomar
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