From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>,
Noah Goldstein <goldstein.w.n@gmail.com>
Subject: Re: [PATCH v2 3/7] string/test-str*cmp: remove stupid_[strcmp, strncmp, wcscmp, wcsncmp].
Date: Mon, 10 Jan 2022 13:56:35 +0000 [thread overview]
Message-ID: <AS8PR08MB65349E404E48248BE5DE042F83509@AS8PR08MB6534.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <87mtk3yblz.fsf@oldenburg.str.redhat.com>
Hi Florian,
> strncmp is commonly used as a starts-with-prefix function, as in:
>
> strncmp (s, "prefix", 6)
>
> This would be the second case: stopping at NUL before the number of
> specified bytes are read.
Indeed, such usage is both common and natural. There is only one size parameter,
so you couldn't ever use strncmp on strings you didn't know the buffer size of,
making it useless. Compilers don't optimize this to memcmp eventhough the C
standard seems to allow that, so the accepted standard is that strn* functions
must stop at the first NUL character.
Cheers,
Wilco
next prev parent reply other threads:[~2022-01-10 13:56 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
2022-01-10 13:09 ` Wilco Dijkstra
2022-01-10 13:16 ` Florian Weimer
2022-01-10 13:56 ` Wilco Dijkstra [this message]
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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