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From: Florian Weimer <fweimer@redhat.com>
To: Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>
Cc: Noah Goldstein <goldstein.w.n@gmail.com>,
	 Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Subject: Re: [PATCH v2 3/7] string/test-str*cmp: remove stupid_[strcmp, strncmp, wcscmp, wcsncmp].
Date: Mon, 10 Jan 2022 13:42:31 +0100	[thread overview]
Message-ID: <87zgo3yd6w.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <AS8PR08MB6534E9868247E248757BE0D183509@AS8PR08MB6534.eurprd08.prod.outlook.com> (Wilco Dijkstra via Libc-alpha's message of "Mon, 10 Jan 2022 11:42:43 +0000")

* Wilco Dijkstra via Libc-alpha:

> Hi Noah,
>
>> These implementations are incorrect. There may be a mismatch in s1/s2
>> before invalid memory but no null CHAR / length boundary.
>
> This is not true, see
> eg. https://en.cppreference.com/w/cpp/string/byte/strcmp.  Most string
> functions require that the string is correctly terminated. There are
> only a few exceptions (memchr IIRC), and several generic
> implementations use strlen or strnlen before the main loop.

I am not sure if those are bugs.  Don't we support non-array usage in
these functions as an extension?  At least for strncmp and strnlen and
their wide counterparts.  C11 is pretty clear that strncmp operates on
arrays, so this is an extension.

Thanks,
Florian


  reply	other threads:[~2022-01-10 12:42 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-10 11:42 Wilco Dijkstra
2022-01-10 12:42 ` Florian Weimer [this message]
2022-01-10 13:09   ` Wilco Dijkstra
2022-01-10 13:16     ` Florian Weimer
2022-01-10 13:56       ` Wilco Dijkstra
2022-01-10 18:39 ` Noah Goldstein
2022-01-10 21:38 ` Noah Goldstein
  -- strict thread matches above, loose matches on Subject: below --
2022-01-09 12:29 [PATCH v1 1/5] x86: Optimize strcmp-avx2.S and fix for [BZ# 28755] Noah Goldstein
2022-01-10  0:27 ` [PATCH v2 1/7] x86: Fix __wcsncmp_avx2 in strcmp-avx2.S " Noah Goldstein
2022-01-10  0:27   ` [PATCH v2 3/7] string/test-str*cmp: remove stupid_[strcmp, strncmp, wcscmp, wcsncmp] Noah Goldstein
2022-01-10  0:37     ` H.J. Lu

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