From: Zack Weinberg <zack@owlfolio.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Zack Weinberg via Gcc <gcc@gcc.gnu.org>,
c-std-porting@lists.linux.dev, autoconf@gnu.org,
cfe-commits@lists.llvm.org, Frederic Berat <fberat@redhat.com>
Subject: Re: How can Autoconf help with the transition to stricter compilation defaults?
Date: Fri, 11 Nov 2022 22:40:21 -0500 [thread overview]
Message-ID: <ypikzgcw96xm.fsf@owlfolio.org> (raw)
In-Reply-To: <87v8nmsmwt.fsf@oldenburg.str.redhat.com> (Florian Weimer's message of "Thu, 10 Nov 2022 19:08:02 +0100")
Florian Weimer <fweimer@redhat.com> writes:
> based on a limited attempt to get this fixed about three years
> ago, I expect that many of the problematic packages have not had their
> configure scripts regenerated using autoconf for a decade or more. This
> means that as an autoconf maintainer, you unfortunately won't be able to
> help us much.
I’m sadly not surprised.
This is definitely more work than I can see myself doing on a volunteer
basis, but a 2.69.1 patch release — nothing that’s not already on trunk,
cherry pick the changes needed to support the newer compilers (and
also newer Perl and Bash and M4) is a thing that could happen.
> Thanks, these changes are going to be helpful to get a clean run from
> our Fedora tester.
Autoconf’s own test suite is sadly not very thorough. If you find more
problems I will prioritize them.
> Once you include the header, you also need to know function parameters,
> otherwise you won't be able to form a valid call.
You can assign to a function pointer variable if you know the complete
type signature, which is desirable for other reasons (see reply to Rich).
Needing to know how to form argument *values* could be much more trouble,
but I don’t think it should be necessary.
>> p.s. GCC and Clang folks: As long as you’re changing the defaults out
>> from under people,
>
> Hmph, I wouldn't frame it this way. We are aware of GCC's special role
> as the system compiler. We're trying to upstream the changes to sources
> before flipping the compiler default. (The burden of being a system
> compiler and all that.) A 25-year transition period evidently wasn't
> enough, so some effort is still needed. We may conclude that removing
> these extensions is too costly even in 2024.
I didn’t mean to imply that I disliked any of the changes. In fact,
with my day job (CS professor) hat on, I am quite looking forward to not
having to warn the kids about these legacy features anymore (we don’t
_teach_ them, but they inevitably use them by accident, particularly
implicit function declarations, and then get confused because ‘cc’ with
no -W options doesn’t catch the mistake).
>> can you please also remove the last few predefined
>> user-namespace macros (-Dlinux, -Dunix, -Darm, etc) from all the
>> -std=gnuXX modes?
>
> That's a good point, I'll think about how we can instrument GCC to
> support tracking that. We won't be able help with -Darm on the Fedora
> side (the AArch64 port doesn't have that, and there's no longer a Fedora
> 32-bit Arm port), but -Dlinux and -Dunix we can help with.
These are also a trip hazard for novices, and the only way to turn them
off is with -std=cXX, which also turns another trip hazard (trigraphs)
*on*… so yeah, anything you can do to help speed up their removal, I
think it’d be worthwhile.
zw
next prev parent reply other threads:[~2022-11-12 3:41 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-10 17:16 Zack Weinberg
2022-11-10 17:52 ` Nick Bowler
2022-11-10 17:58 ` Jonathan Wakely
2022-11-10 18:12 ` Jonathan Wakely
2022-11-10 18:44 ` Aaron Ballman
2022-11-12 2:56 ` Zack Weinberg
2022-11-10 18:05 ` Rich Felker
2022-11-10 21:44 ` Florian Weimer
2022-11-12 3:22 ` Zack Weinberg
2022-11-10 18:08 ` Florian Weimer
2022-11-12 3:40 ` Zack Weinberg [this message]
2022-11-12 3:43 ` Sam James
2022-11-12 14:27 ` Zack Weinberg
2022-11-12 3:45 ` Joseph Myers
2022-11-12 15:59 ` Wookey
2022-11-12 16:12 ` Zack Weinberg
2022-11-10 18:19 ` Aaron Ballman
2022-11-10 21:05 ` Paul Eggert
2022-11-11 15:11 ` Aaron Ballman
2022-11-13 0:43 ` Paul Eggert
2022-11-14 12:41 ` Aaron Ballman
2022-11-14 18:14 ` Paul Eggert
2022-11-14 18:30 ` Florian Weimer
2022-11-14 18:35 ` Aaron Ballman
2022-11-15 14:50 ` Jonathan Wakely
2022-11-15 19:08 ` Paul Eggert
2022-11-15 19:27 ` Jonathan Wakely
2022-11-15 20:27 ` Paul Eggert
2022-11-15 20:57 ` Aaron Ballman
2022-11-15 23:09 ` Paul Eggert
2022-11-15 23:43 ` Ben Boeckel
2022-11-16 14:26 ` Michael Matz
2022-11-16 14:40 ` Alexander Monakov
2022-11-16 15:01 ` Michael Matz
2022-11-16 15:27 ` Richard Biener
2022-11-16 15:35 ` Sam James
2022-11-16 15:59 ` Michael Matz
2022-11-16 16:20 ` Jonathan Wakely
2022-11-16 16:34 ` Michael Matz
2022-11-16 16:46 ` Jonathan Wakely
2022-11-16 18:17 ` Paul Eggert
2022-11-16 18:40 ` Jeffrey Walton
2022-11-17 18:45 ` Paul Eggert
2022-11-16 18:59 ` Zack Weinberg
2022-11-17 18:58 ` Paul Eggert
2022-11-17 21:35 ` Bruno Haible
2022-11-17 22:27 ` Paul Eggert
2022-11-17 13:30 ` Michael Matz
2022-11-15 20:36 ` Aaron Ballman
2022-11-15 5:03 ` Sam James
2022-11-15 13:30 ` Zack Weinberg
2022-11-15 13:34 ` Sam James
2022-11-16 0:08 ` Bob Friesenhahn
2022-11-13 0:43 ` Paul Eggert
2022-11-17 13:57 ` Jason Merrill
2022-11-10 20:19 ` Paul Eggert
[not found] ` <d785b19371e8419f5a5817d7cdb429db91614a3a.camel@orlitzky.com>
2022-11-11 3:08 ` Sam James
2022-11-11 3:33 ` Zack Weinberg
2022-11-11 8:40 ` Sam James
2022-11-11 9:02 ` Paul Eggert
2022-11-12 14:09 ` Zack Weinberg
2022-11-11 23:25 ` Sam James
2022-11-12 0:53 ` Paul Eggert
2022-11-12 4:00 ` Sam James
2022-11-11 9:15 ` Sam James
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