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From: Paul Eggert <eggert@cs.ucla.edu>
To: Eli Zaretskii <eliz@gnu.org>
Cc: fabrice.popineau@centralesupelec.fr, andrewjmoreton@gmail.com,
	emacs-devel@gnu.org
Subject: Re: Suspicious warning in W64 build
Date: Sun, 17 Sep 2017 10:07:42 -0700	[thread overview]
Message-ID: <0feb1250-beb8-5a21-0582-c879f922bb1c@cs.ucla.edu> (raw)
In-Reply-To: <83bmm9jt23.fsf@gnu.org>

Eli Zaretskii wrote:
> UNINIT looked inappropriate to initialize a Lisp_Object which is
> supposed to be a number.
No, it's appropriate. UNINIT is merely a declaration directive. It tells GCC 
"This variable is not initialized and that is OK; don't warn me about it, I know 
that the initial value is never used even though you may not know." The current 
UNINIT implementation would still work even if we were to change the Lisp_Object 
representation so that all-zero would become invalid, because UNINIT declares 
that the invalid value will not be used.

No code should depend on UNINIT initializing to zero, as this is not true in 
general.

Although args[0] stops GCC from complaining, it is less useful than UNINIT 
because it will make cleanup more difficult in the future. We're already using 
UNINIT for Lisp_Object variables elsewhere, so we already know it's safe to use 
here.



  parent reply	other threads:[~2017-09-17 17:07 UTC|newest]

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-05 13:38 Suspicious warning in W64 build Angelo Graziosi
2017-09-05 14:04 ` Richard Copley
2017-09-07 15:16 ` Eli Zaretskii
2017-09-07 15:42   ` Angelo Graziosi
2017-09-07 17:52     ` Richard Copley
2017-09-07 17:58       ` Richard Copley
2017-09-07 19:00         ` Angelo Graziosi
2017-09-07 19:21           ` Richard Copley
2017-09-09  4:58             ` Herring, Davis
2017-09-09  9:55               ` Richard Copley
2017-09-09 10:20                 ` Eli Zaretskii
2017-09-09 11:24                   ` Angelo Graziosi
2017-09-09 13:25                     ` Eli Zaretskii
2017-09-09 11:16                 ` Angelo Graziosi
2017-09-07 18:58       ` Eli Zaretskii
2017-09-07 19:26         ` Paul Eggert
2017-09-07 19:50           ` Richard Copley
2017-09-07 20:02             ` Richard Copley
2017-09-08  6:49               ` Eli Zaretskii
2017-09-08  8:02                 ` Eli Zaretskii
2017-09-08 19:31                   ` Richard Copley
2017-09-08 20:17                     ` Eli Zaretskii
2017-09-08 21:08                       ` Richard Copley
2017-09-08 21:37                         ` Richard Copley
2017-09-09  7:37                           ` Eli Zaretskii
2017-09-08 22:20                         ` Richard Copley
2017-09-09  7:33                         ` Eli Zaretskii
2017-09-09  9:36                           ` Richard Copley
2017-09-09 10:42                             ` Eli Zaretskii
2017-09-09 10:52                               ` Eli Zaretskii
2017-09-09 11:17                               ` Richard Copley
2017-09-09 16:07                                 ` Eli Zaretskii
2017-09-10  1:01                                   ` Richard Copley
2017-09-10 14:40                                     ` Eli Zaretskii
2017-09-10 19:14                                       ` Richard Copley
2017-09-10 19:38                                         ` Angelo Graziosi
2017-09-11 16:17                                           ` Eli Zaretskii
2017-09-11 22:21                                             ` Angelo Graziosi
2017-09-11 16:39                                           ` Óscar Fuentes
2017-09-11 17:20                                             ` Eli Zaretskii
2017-09-12 17:49                                   ` Eli Zaretskii
2017-09-12 18:01                                     ` Fabrice Popineau
2017-09-12 18:37                                       ` Richard Copley
2017-09-12 18:59                                         ` Eli Zaretskii
2017-09-12 19:14                                           ` Richard Copley
2017-09-12 18:38                                       ` Eli Zaretskii
2017-09-14 17:47                                         ` Eli Zaretskii
2017-09-14 19:34                                           ` Richard Copley
2017-09-15  8:54                                             ` Eli Zaretskii
2017-09-15 23:05                                               ` Richard Copley
2017-09-16  6:40                                                 ` Eli Zaretskii
2017-09-16  8:19                                                   ` Richard Copley
2017-09-16  8:34                                                     ` Richard Copley
2017-09-16  8:54                                                       ` Eli Zaretskii
2017-09-16  9:07                                                         ` Richard Copley
2017-09-16 11:54                                                           ` Fabrice Popineau
2017-09-16  8:52                                                     ` Eli Zaretskii
2017-09-15  8:59                                             ` Eli Zaretskii
2017-09-15 14:43                                               ` Eli Zaretskii
2017-09-17  6:42                                                 ` Paul Eggert
2017-09-17  7:14                                                   ` Richard Copley
2017-09-17 14:31                                                     ` Eli Zaretskii
2017-09-17  6:40                                               ` Paul Eggert
2017-09-17 14:29                                                 ` Eli Zaretskii
2017-09-17 16:39                                                   ` Fabrice Popineau
2017-09-17 16:52                                                     ` Eli Zaretskii
2017-09-18  0:26                                                   ` Paul Eggert
2017-09-18 11:47                                                     ` Fabrice Popineau
2017-09-18 14:46                                                       ` Eli Zaretskii
2017-09-18  0:01                                                 ` Richard Stallman
2017-09-14 19:36                                           ` Fabrice Popineau
2017-09-14 21:17                                           ` Andy Moreton
2017-09-15  6:55                                             ` Fabrice Popineau
2017-09-15  9:12                                               ` Eli Zaretskii
2017-09-15 15:33                                                 ` Fabrice Popineau
2017-09-15 15:45                                                   ` Eli Zaretskii
2017-09-15 18:15                                                     ` Fabrice Popineau
2017-09-15 19:00                                                       ` Eli Zaretskii
2017-09-15 21:02                                                         ` Fabrice Popineau
2017-09-16  7:45                                                           ` Eli Zaretskii
2017-09-17  7:01                                                             ` Paul Eggert
2017-09-17 14:31                                                               ` Eli Zaretskii
2017-09-17 14:52                                                                 ` Philipp Stephani
2017-09-17 22:34                                                                   ` Paul Eggert
2017-09-17 17:07                                                                 ` Paul Eggert [this message]
2017-09-17 17:14                                                                   ` Eli Zaretskii
2017-09-17 18:53                                                                     ` Paul Eggert
2017-09-17 19:30                                                                       ` Eli Zaretskii
2017-09-17 20:34                                                                         ` Paul Eggert
2017-09-18  2:30                                                                           ` Eli Zaretskii
2017-09-18  4:52                                                                             ` Paul Eggert
2017-09-18 14:41                                                                               ` Eli Zaretskii
2017-09-18 17:35                                                                                 ` Paul Eggert
2017-09-18 17:58                                                                                   ` Andy Moreton
2017-09-19  9:05                                                                                     ` Paul Eggert
2017-09-18 18:01                                                                                   ` Eli Zaretskii
2017-09-17 20:45                                                   ` Paul Eggert
2017-09-16 13:17                                                 ` Andy Moreton
2017-09-16 13:46                                                   ` Eli Zaretskii
2017-09-16 18:57                                                     ` Richard Copley
2017-09-16 19:21                                                       ` Eli Zaretskii
2017-09-15  9:03                                             ` Eli Zaretskii
2017-09-09  8:49                       ` Angelo Graziosi
2017-09-09 10:37                         ` Eli Zaretskii
2017-09-09 11:32                           ` Angelo Graziosi
2017-09-09 13:28                             ` Eli Zaretskii
2017-09-09 13:33                               ` Fabrice Popineau
2017-09-09 14:55                               ` Angelo Graziosi
2017-09-09 16:37                                 ` Eli Zaretskii
2017-09-09 18:38                                   ` Angelo Graziosi
2017-09-09 18:59                                     ` Eli Zaretskii
2017-09-09 21:29                                       ` Angelo Graziosi
2017-09-10 14:56                                         ` Eli Zaretskii
2017-09-10 15:45                                           ` Angelo Graziosi
2017-09-10 16:02                                             ` Eli Zaretskii
2017-09-10 18:45                                               ` Angelo Graziosi
2017-09-10 19:43                                                 ` Eli Zaretskii
2017-09-09 15:40                           ` Angelo Graziosi
2017-09-09 16:40                             ` Eli Zaretskii
2017-09-09 18:33                               ` Fabrice Popineau
2017-09-07 20:20           ` Eli Zaretskii
2017-09-07 21:59             ` Angelo Graziosi
2017-09-08  8:01               ` Eli Zaretskii

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