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From: "James K. Lowden" <jklowden@schemamania.org>
To: David Brown via Gcc <gcc@gcc.gnu.org>
Subject: Re: More C type errors by default for GCC 14
Date: Thu, 11 May 2023 06:49:39 -0400	[thread overview]
Message-ID: <20230511064939.8e78f6eb2ac1e471dd7588a3@schemamania.org> (raw)
In-Reply-To: <u3ftgv$sof$1@ciao.gmane.io>

On Wed, 10 May 2023 13:00:46 +0200
David Brown via Gcc <gcc@gcc.gnu.org> wrote:

> or that function calls always act as a 
> memory barrier.

Hi David, [off list]

Could you tell me more about that, and where I could read about it?  

I've only been using C since 1985, so just a beginner, I guess. ;-)
As a  matter of C semantics, I can't see how a function call could be
anything but a memory barrier.  The arguments have to be resolved before
the function is called, else there's no value to provide.  And the
function has to determine its return value prior to returning.  

I can imagine in the face of multithreading that things become murky,
but that's the nature of multithreading as commonly implemented.  It's
outside C semantics.  

I'm genuinely curious what it is your referring to, in case my
understanding is out of date.  

--jkl

  reply	other threads:[~2023-05-11 15:30 UTC|newest]

Thread overview: 246+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-09 12:15 Florian Weimer
2023-05-09 14:16 ` Dave Blanchard
2023-05-09 15:03 ` David Edelsohn
2023-05-09 15:07   ` Sam James
2023-05-09 15:35     ` Dave Blanchard
2023-05-09 15:58       ` Jonathan Wakely
2023-05-09 16:26       ` Arsen Arsenović
2023-05-09 15:14   ` Jonathan Wakely
2023-05-09 15:22     ` Dave Blanchard
2023-05-09 16:38       ` Arsen Arsenović
2023-05-09 16:57         ` Eli Zaretskii
2023-05-09 17:05           ` Sam James
2023-05-09 18:55             ` Eli Zaretskii
2023-05-09 17:15           ` Jonathan Wakely
2023-05-09 19:04             ` Eli Zaretskii
2023-05-09 19:07               ` Jakub Jelinek
2023-05-09 19:22                 ` Eli Zaretskii
2023-05-09 20:13                   ` David Edelsohn
2023-05-09 20:21                     ` Arsen Arsenović
2023-05-10  2:38                       ` Eli Zaretskii
2023-05-10  8:36                         ` Arsen Arsenović
2023-05-10 11:52                           ` Eli Zaretskii
2023-05-10 11:56                             ` Jonathan Wakely
2023-05-10 12:25                               ` Eli Zaretskii
2023-05-10 12:30                                 ` Jonathan Wakely
2023-05-10 12:44                                   ` Eli Zaretskii
2023-05-15 12:28                         ` Richard Earnshaw (lists)
2023-05-15 20:17                           ` Eric Gallager
2023-05-16  7:05                             ` Florian Weimer
2023-05-16 15:56                               ` Jason Merrill
2023-05-09 20:40                     ` Jonathan Wakely
2023-05-09 22:27                       ` David Edelsohn
2023-05-09 22:37                         ` Joel Sherrill
2023-05-09 22:45                           ` Jonathan Wakely
2023-05-10 10:40                             ` Eric Gallager
2023-05-10 10:45                               ` Sam James
2023-05-10 10:56                                 ` Neal Gompa
2023-05-10 12:06                                   ` Eli Zaretskii
2023-05-10 12:10                                     ` Neal Gompa
2023-05-10 12:41                                       ` Eli Zaretskii
2023-05-10 10:48                               ` Jonathan Wakely
2023-05-10 10:51                                 ` Jonathan Wakely
2023-05-10 12:00                               ` Eli Zaretskii
2023-05-10 12:42                                 ` Sam James
2023-05-10 15:10                             ` Joel Sherrill
2023-05-10 15:14                               ` Jakub Jelinek
2023-05-10 16:36                                 ` Joel Sherrill
2023-05-10 16:44                                   ` Jakub Jelinek
2023-05-10 17:05                                   ` Jonathan Wakely
2023-05-10 18:37                             ` James K. Lowden
2023-05-10 23:26                               ` Jonathan Wakely
2023-05-11 18:47                                 ` Jason Merrill
2023-05-10 23:33                               ` Sam James
2023-05-11  5:48                               ` Eli Zaretskii
2023-05-11  2:28                             ` Po Lu
2023-05-11  2:09                       ` Po Lu
2023-05-11  2:14                         ` Sam James
2023-05-11  2:23                           ` Po Lu
2023-05-11  3:14                             ` Eli Schwartz
2023-05-11  3:56                               ` Po Lu
2023-05-11  4:46                                 ` Eli Schwartz
2023-05-11  4:49                                   ` Eli Schwartz
2023-05-11  6:23                                     ` Po Lu
2023-05-11  6:18                                   ` Po Lu
2023-05-11 22:41                                     ` Eli Schwartz
2023-05-12  2:08                                       ` Po Lu
2023-05-12  3:07                                         ` Eli Schwartz
2023-05-12  5:57                                           ` Po Lu
2023-05-12 11:05                                             ` Gabriel Ravier
2023-05-12 13:53                                               ` Po Lu
2023-05-12 14:03                                                 ` Jonathan Wakely
2023-05-14 12:35                                                 ` Mark Wielaard
2023-05-12 11:48                                             ` Is the GNUC dialect anything that GCC does when given source code containing UB? (Was: More C type errors by default for GCC 14) Eli Schwartz
2023-05-12 13:07                                               ` Is the GNUC dialect anything that GCC does when given source code containing UB? Po Lu
2023-05-12  6:56                                           ` More C type errors by default for GCC 14 Eli Zaretskii
2023-05-12  7:28                                             ` Jonathan Wakely
2023-05-12 10:36                                               ` Eli Zaretskii
2023-05-12 13:19                                               ` Po Lu
2023-05-12 13:25                                                 ` Gabriel Ravier
2023-05-13  0:45                                                   ` Po Lu
2023-05-13  5:30                                                     ` Thomas Koenig
2023-05-13  5:53                                                       ` Po Lu
2023-05-14  5:10                                                         ` Eli Schwartz
2023-05-14  5:38                                                           ` Po Lu
2023-05-14  9:46                                                             ` David Brown
2023-05-14 10:21                                                               ` Jonathan Wakely
2023-05-14 10:23                                                                 ` Jonathan Wakely
2023-05-14  5:08                                                     ` Eli Schwartz
2023-05-14  5:28                                                       ` Po Lu
2023-05-14  5:56                                                         ` Eli Schwartz
2023-05-14 11:55                                                           ` Po Lu
2023-05-14 12:22                                                             ` Arsen Arsenović
2023-05-15  1:05                                                               ` Po Lu
2023-05-14  6:03                                                         ` Eli Schwartz
2023-05-14  8:47                                                         ` Jonathan Wakely
2023-05-14 12:05                                                           ` Po Lu
2023-05-14 12:48                                                             ` Nicholas Vinson
2023-05-14 10:29                                                         ` David Brown
2023-05-12 15:51                                                 ` Jason Merrill
2023-05-17 10:06                                                   ` Florian Weimer
2023-05-12 11:26                                         ` David Brown
2023-05-11  6:24                                   ` Eli Zaretskii
2023-05-11 22:43                                     ` Eli Schwartz
2023-05-12  2:38                                       ` Po Lu
2023-05-12  2:55                                         ` Jason Merrill
2023-05-12  6:01                                           ` Po Lu
2023-05-12  6:40                                             ` Jonathan Wakely
2023-05-12 13:23                                               ` Po Lu
2023-05-12 10:49                                             ` Pedro Alves
2023-05-12 13:26                                               ` Po Lu
2023-05-12 11:55                                             ` Eli Schwartz
2023-05-12 13:54                                               ` Po Lu
2023-05-12  6:49                                           ` Eli Zaretskii
2023-05-12  2:56                                         ` Sam James
2023-05-12  6:03                                           ` Po Lu
2023-05-12  3:06                                         ` Sam James
2023-05-12  6:25                                       ` Eli Zaretskii
2023-05-12 11:23                                         ` Gabriel Ravier
2023-05-11  6:12                               ` Eli Zaretskii
2023-05-11  7:04                                 ` Jonathan Wakely
2023-05-11 22:30                                 ` Eli Schwartz
2023-05-11 22:35                                   ` Sam James
2023-05-12  2:40                                     ` Po Lu
2023-05-12  2:52                                       ` Sam James
2023-05-12  5:32                                         ` Po Lu
2023-05-12  2:39                                   ` Po Lu
2023-05-12  3:18                                     ` Eli Schwartz
2023-05-12  6:17                                   ` Eli Zaretskii
2023-05-11  7:59                         ` David Brown
2023-05-09 21:00                     ` Thomas Koenig
2023-05-09 21:17                       ` Arsen Arsenović
2023-05-10 13:57                       ` Florian Weimer
2023-05-10 11:00                     ` David Brown
2023-05-11 10:49                       ` James K. Lowden [this message]
2023-05-11  1:38                     ` Po Lu
2023-05-11  1:43                       ` Sam James
2023-05-11  2:20                         ` Po Lu
2023-05-09 20:57                   ` Florian Weimer
2023-05-10  2:33                     ` Eli Zaretskii
2023-05-10  8:04                       ` Jonathan Wakely
2023-05-10  8:46                         ` Richard Biener
2023-05-10 12:26                           ` Florian Weimer
2023-05-10 11:30                         ` Eli Zaretskii
2023-05-10 12:03                           ` Jakub Jelinek
2023-05-10 12:36                             ` Eli Zaretskii
2023-05-10 12:41                               ` Gabriel Ravier
2023-05-10 14:14                                 ` Eli Zaretskii
2023-05-10 14:22                                   ` Jakub Jelinek
2023-05-10 15:30                                     ` Eli Zaretskii
2023-05-10 16:02                                       ` Jakub Jelinek
2023-05-10 16:31                                         ` Eli Zaretskii
2023-05-10 16:33                                           ` Richard Biener
2023-05-10 16:57                                             ` Eli Zaretskii
2023-05-10 17:08                                           ` Joseph Myers
2023-05-10 18:18                                             ` Eli Zaretskii
2023-05-12 15:02                                             ` Florian Weimer
2023-05-12 17:52                                               ` Florian Weimer
2023-05-12 17:55                                                 ` Gabriel Ravier
2023-05-12 18:00                                                   ` Florian Weimer
2023-05-12 18:08                                                   ` Alexander Monakov
2023-05-12 18:14                                                     ` Florian Weimer
2023-05-15 12:51                                                       ` Michael Matz
2023-05-16  8:55                                                         ` Florian Weimer
2023-05-16 10:39                                                           ` Alexander Monakov
2023-05-16 11:01                                                             ` Jakub Jelinek
2023-05-16 11:09                                                               ` Jonathan Wakely
2023-05-16 11:15                                                               ` Florian Weimer
2023-05-12 19:44                                               ` Joseph Myers
2023-05-12 20:43                                                 ` Florian Weimer
2023-05-12 20:18                                               ` Jason Merrill
2023-05-12 20:57                                                 ` Florian Weimer
2023-05-12 21:20                                                   ` Sam James
2023-05-12 21:21                                               ` Sam James
2023-05-12 21:37                                                 ` Florian Weimer
2023-05-12 21:47                                                   ` Sam James
2023-05-12 21:59                                                     ` Florian Weimer
2023-05-10 15:58                                   ` David Brown
2023-05-10 16:28                                     ` Eli Zaretskii
2023-05-11  6:52                                       ` David Brown
2023-05-11  7:39                                         ` Eli Zaretskii
2023-05-10 14:31                             ` Thomas Koenig
2023-05-10 15:37                               ` Eli Zaretskii
2023-05-11  2:38                         ` Po Lu
2023-05-11  7:38                           ` Arsen Arsenović
2023-05-11  8:31                             ` Po Lu
2023-05-11  8:44                               ` Arsen Arsenović
2023-05-11  9:28                                 ` Po Lu
2023-05-11 21:10                                   ` Arsen Arsenović
2023-05-12  1:41                                     ` Po Lu
2023-05-11 10:35                                 ` Eli Zaretskii
2023-05-11 19:25                                   ` Arsen Arsenović
2023-05-12  2:36                                     ` Po Lu
2023-05-12 12:30                                       ` Gabriel Ravier
2023-05-12 13:56                                         ` Po Lu
2023-05-12  7:53                                     ` Eli Zaretskii
2023-05-12  8:15                                       ` Jakub Jelinek
2023-05-12 10:40                                         ` Eli Zaretskii
2023-05-12  8:45                                       ` Christian Groessler
2023-05-12 10:14                                         ` Jonathan Wakely
2023-05-12  9:11                                       ` Thomas Koenig
2023-05-11  8:53                               ` Jonathan Wakely
2023-05-11  9:29                                 ` Po Lu
2023-05-10  8:49               ` David Brown
2023-05-10 11:37                 ` Eli Zaretskii
2023-05-10 11:49                   ` Jonathan Wakely
2023-05-10 12:22                     ` Eli Zaretskii
2023-05-10 13:30                       ` David Brown
2023-05-10 14:39                         ` Eli Zaretskii
2023-05-10 15:21                           ` Paul Koning
2023-05-10 16:20                           ` David Brown
2023-05-10 16:48                             ` Eli Zaretskii
2023-05-10 12:32                   ` Sam James
2023-05-10 12:47                     ` Eli Zaretskii
2023-05-09 19:33           ` Arsen Arsenović
2023-05-09 15:25     ` David Edelsohn
2023-05-11  1:25     ` Po Lu
2023-05-11  1:30       ` Sam James
2023-05-11  1:33       ` Sam James
2023-05-11  2:18         ` Po Lu
2023-05-11  6:44           ` Jonathan Wakely
2023-05-11  8:32             ` Po Lu
2023-05-11  8:52               ` Jonathan Wakely
2023-05-11  7:36       ` Arsen Arsenović
2023-05-11  8:23         ` Po Lu
2023-05-09 18:22   ` Florian Weimer
2023-05-11 21:32     ` Segher Boessenkool
2023-05-09 15:16 ` Richard Biener
2023-05-09 16:05   ` Jakub Jelinek
2023-05-09 16:11     ` Sam James
2023-05-09 16:13     ` David Edelsohn
     [not found]       ` <BBE9950C-28AA-4A1C-A4C5-7F486538004E@gmail.com>
2023-05-09 16:44         ` Florian Weimer
2023-05-09 16:58           ` Ian Lance Taylor
2023-05-09 17:08           ` Jason Merrill
2023-05-09 17:16             ` Sam James
2023-05-09 16:59   ` Florian Weimer
2023-05-09 17:07     ` Sam James
2023-05-09 17:35       ` Florian Weimer
2023-05-11 15:21 ` Peter0x44
2023-05-12  9:33 ` Martin Jambor
2023-05-12 12:30   ` Jakub Jelinek
2023-05-15 12:46     ` Michael Matz
2023-05-15 13:14     ` Richard Earnshaw (lists)
2023-05-10 12:41 Marcin Jaczewski
2023-05-10 14:19 ` Eli Zaretskii
2023-05-10 13:10 Basile Starynkevitch
2023-05-10 14:20 ` David Brown

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