From: Vincent Lefevre <vincent@vinc17.net>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Alejandro Colomar <alx.manpages@gmail.com>,
libc-alpha@sourceware.org, Stephan Bergmann <sbergman@redhat.com>,
Paul Eggert <eggert@cs.ucla.edu>,
Simon Chopin <simon.chopin@canonical.com>
Subject: Re: UB status of snprintf on invalid ptr+size combination?
Date: Sun, 19 Mar 2023 23:48:09 +0100 [thread overview]
Message-ID: <20230319224809.GC390223@zira.vinc17.org> (raw)
In-Reply-To: <875yayyuh8.fsf@igel.home>
On 2023-03-18 16:01:07 +0100, Andreas Schwab wrote:
> On Mär 18 2023, Vincent Lefevre wrote:
>
> > However, I'm wondering whether such a change is intentional. BTW,
> > this description is even wrong: this is certainly not equivalent!
> > If the untruncated output is larger than n, then the call is UB
> > with sprintf(), while the output is truncated with snprintf().
>
> Which makes them equivalent in all situations where sprintf is defined,
> so there is no discrepancy here.
The conditions under which the function is defined or not are part of
the equivalence. For instance, I would not say that memcpy and memmove
are equivalent, even though they are equivalent when memcpy is defined.
--
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:[~2023-03-19 22:48 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-14 19:47 Simon Chopin
2023-03-14 21:39 ` Paul Eggert
2023-03-15 9:22 ` Andreas Schwab
2023-03-15 15:54 ` Siddhesh Poyarekar
2023-03-15 18:34 ` Michael Hudson-Doyle
2023-03-19 14:45 ` manfred
2023-03-19 23:07 ` Vincent Lefevre
2023-03-20 12:05 ` Siddhesh Poyarekar
2023-03-20 12:17 ` Alejandro Colomar
2023-03-20 12:29 ` Siddhesh Poyarekar
2023-03-20 13:36 ` Vincent Lefevre
2023-03-20 13:50 ` Vincent Lefevre
2023-03-20 16:56 ` Siddhesh Poyarekar
2023-03-20 17:36 ` Vincent Lefevre
2023-03-20 15:09 ` Vincent Lefevre
2023-03-20 16:15 ` Alejandro Colomar
2023-03-20 16:33 ` Vincent Lefevre
2023-03-20 17:00 ` Vincent Lefevre
2023-03-20 17:31 ` Siddhesh Poyarekar
2023-03-20 17:45 ` Vincent Lefevre
2023-03-15 12:39 ` Vincent Lefevre
2023-03-16 10:29 ` Stephan Bergmann
2023-03-18 2:07 ` Vincent Lefevre
2023-03-18 2:30 ` Alejandro Colomar
2023-03-18 10:58 ` Vincent Lefevre
2023-03-18 15:01 ` Andreas Schwab
2023-03-19 22:48 ` Vincent Lefevre [this message]
2023-03-19 23:24 ` Andreas Schwab
2023-03-20 4:10 ` Vincent Lefevre
2023-03-20 9:19 ` Andreas Schwab
2023-03-20 10:42 ` Vincent Lefevre
2023-03-20 10:44 ` Andreas Schwab
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