From: Vincent Lefevre <vincent@vinc17.net>
To: Xi Ruoyao <xry111@xry111.site>,
Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>,
Turritopsis Dohrnii Teo En Ming <teo.en.ming@protonmail.com>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
"ceo@teo-en-ming-corp.com" <ceo@teo-en-ming-corp.com>
Subject: Re: New GNU C Library (glibc) security flaw reported on 30 Jan 2024
Date: Thu, 1 Feb 2024 02:03:35 +0100 [thread overview]
Message-ID: <20240201010335.GG3044@qaa.vinc17.org> (raw)
In-Reply-To: <20240201005155.GF3044@qaa.vinc17.org>
On 2024-02-01 01:51:55 +0100, Vincent Lefevre wrote:
> Yes, the point is to sort numbers. But since NaN may occur, the code
> must not yield undefined behavior in such a case. This is the goal
> of NaN: avoid undefined behavior for operations that do not make any
> sense, and be able to detect errors at the end.
BTW, note that the ISO C standard sometimes uses "number" even
when this can be a NaN. For instance, in 7.12.7.2:
The fabs functions compute the absolute value of a
floating-point number x.
(though this has been changed in C23). But the term "number"
is still used in C23 for ceil and floor.
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
next prev parent reply other threads:[~2024-02-01 1:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-31 14:08 New GNU C Library (glibc) security flaw reported on 30 Jan 2024 Turritopsis Dohrnii Teo En Ming
2024-01-31 14:23 ` Xi Ruoyao
2024-01-31 14:55 ` Vincent Lefevre
2024-01-31 15:52 ` Adhemerval Zanella Netto
2024-01-31 16:23 ` Vincent Lefevre
2024-01-31 16:44 ` Siddhesh Poyarekar
2024-01-31 18:47 ` Xi Ruoyao
2024-02-01 0:51 ` Vincent Lefevre
2024-02-01 1:03 ` Vincent Lefevre [this message]
2024-02-01 6:41 ` Xi Ruoyao
2024-02-01 9:07 ` Vincent Lefevre
2024-02-01 19:55 ` Paul Eggert
2024-02-01 21:11 ` Siddhesh Poyarekar
2024-02-05 0:58 ` Paul Eggert
2024-02-06 15:00 ` Zack Weinberg
2024-02-06 21:30 ` Paul Eggert
2024-02-06 22:04 ` Xi Ruoyao
2024-02-07 17:07 ` Zack Weinberg
2024-02-07 19:55 ` Alexander Monakov
2024-02-07 20:45 ` Zack Weinberg
2024-02-07 21:53 ` Alexander Monakov
2024-02-07 22:56 ` Paul Eggert
2024-04-06 17:17 ` Paul Eggert
2024-04-08 8:28 ` Florian Weimer
2024-04-22 14:39 ` Zack Weinberg
2024-04-23 18:09 ` Paul Eggert
2024-04-23 18:26 ` Florian Weimer
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