Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Kaz Kylheku <433-929-6894@kylheku.com>
Newsgroups: comp.lang.c
Subject: Re: Word For Today: =?UTF-8?Q?=E2=80=9CUglification=E2=80=9D?=
Date: Fri, 15 Mar 2024 03:17:51 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 65
Message-ID: <20240314195148.755@kylheku.com>
References: <uso6or$3t3jn$3@dont-email.me> <20240311202758.193@kylheku.com>
 <86v85opw22.fsf@linuxsc.com> <87v85o4i1v.fsf@nosuchdomain.example.com>
 <87msr04afd.fsf@nosuchdomain.example.com>
 <lIMIN.574792$xHn7.491768@fx14.iad>
 <87il1o44oi.fsf@nosuchdomain.example.com>
Injection-Date: Fri, 15 Mar 2024 03:17:51 -0000 (UTC)
Injection-Info: dont-email.me; posting-host="8c47a74d86a279d136db227d771d8013";
	logging-data="2205442"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19rXLv2fSY3xtLr1pWyNNW9pkaudMoYOY8="
User-Agent: slrn/pre1.0.4-9 (Linux)
Cancel-Lock: sha1:lxtWg6PG0bQhoDGs48UkahUh2kI=
Bytes: 3505

On 2024-03-15, Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote:
> scott@slp53.sl.home (Scott Lurndal) writes:
>> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>>Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>>[...]
>>>> For context, here's the entire file from my system (Ubuntu 24.0.4,
>>>> package libc6-dev:amd64 2.35-0ubuntu3.6).  I get the impression that the
>>>> author(s) decided not to use memset to avoid the required #include,
>>>> which might increase compilation times for code that indirectly includes
>>>> this header.  (I offer no opinion on whether that's a good tradeoff.)
>>>[...]
>>>
>>>An older version did use memset().  It was changed to use a loop in
>>>1997, with a commit message that included:
>>>    "Don't use memset to prevent prototype trouble, use simple loop."
>>>It may have been to avoid problems with pre-ANSI C compilers that didn't
>>>support prototypes.  That's still speculation on my part.
>>
>> Here's the full fc20 version:
>> $ rpm -q -f /usr/include/bits/select.h
>> glibc-headers-2.18-19.fc20.x86_64
>>
>>
> [...]
>> #if defined __GNUC__ && __GNUC__ >= 2

Whoever wrote this didn't know that if __GNUC__ doesn't exist, it will
expand as 0, which is false, so this is equivalent to just

  #if __GNUC__ >= 2

> [...]
>> #else   /* ! GNU CC */
> [...]
>> #endif  /* GNU CC */
> [...]
>
> I don't see that in the GNU glibc git repo, even on branches with
> "fedora" in their names.  Perhaps it's a change applied by Red Hat and
> not propagated upstream.  (Though I'm not sure why Red Hat would need to
> allow for glibc not being compiled by gcc.)

That it's checking for GNU C at least 2 suggests it is an old
patch.

If you look at the source directory for Fedora's package, you see
there are a bunch of patches that get applied:

https://src.fedoraproject.org/rpms/glibc/tree/rawhide

Now if we go to "f20", a heck of lot more patches were applied:

https://src.fedoraproject.org/rpms/glibc/tree/f20

Now, don't waste your time; it's not in any of those patches (I looked).

f20 references glibc-2.18.tar.gz, and that's where that code is found,
in this file:

  ./glibc-2.18/sysdeps/x86/bits/select.h

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca