From: Florian Weimer <fw@deneb.enyo.de>
To: Jonny Grant <jg@jguk.org>
Cc: linux-man <linux-man@vger.kernel.org>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: strlen
Date: Wed, 07 Jul 2021 00:11:37 +0200 [thread overview]
Message-ID: <87bl7fozxi.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <48e874cb-2b95-2783-ddfc-ae12d9aaf8f5@jguk.org> (Jonny Grant's message of "Tue, 6 Jul 2021 21:30:18 +0100")
* Jonny Grant:
> The reason it does not crash appears to be because of this warning
> which removes the call to strlen due to the return not being
> checked?
GCC uses the information that the argument to strlen cannot be null on
that particular path.
> strlen.c:11:3: warning: statement with no effect [-Wunused-value]
> 11 | strlen (str);
> | ^~~~~~~~~~~~
>
> https://godbolt.org/z/caoes5nGa
That site probably uses different library headers.
As posted, with Debian's GCC 8.3, I get this for the main function:
main:
xorl %eax, %eax
ret
next prev parent reply other threads:[~2021-07-06 22:16 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 18:01 strlen Jonny Grant
2020-09-04 19:21 ` strlen Florian Weimer
2020-09-04 23:14 ` strlen Jonny Grant
2020-09-05 7:12 ` strlen Florian Weimer
2021-07-06 20:30 ` strlen Jonny Grant
2021-07-06 22:11 ` Florian Weimer [this message]
2021-07-07 11:36 ` strlen Jonny Grant
2021-07-07 12:22 ` strlen Alejandro Colomar (man-pages)
2021-07-07 12:31 ` strlen Alejandro Colomar (man-pages)
2021-07-07 13:31 ` strlen Jonny Grant
2021-07-07 16:57 ` strlen Alejandro Colomar (man-pages)
2021-07-07 17:23 ` strlen Alejandro Colomar (man-pages)
2021-07-07 17:33 ` strlen Alejandro Colomar (man-pages)
2021-07-09 13:48 ` strlen Jonny Grant
2021-07-08 10:07 ` strlen Jonny Grant
2021-07-08 11:06 ` strlen Alejandro Colomar (man-pages)
2021-07-08 12:13 ` strlen Xi Ruoyao
2021-07-08 23:49 ` strlen Segher Boessenkool
2021-07-09 13:54 ` strlen Jonny Grant
2021-07-09 14:17 ` strlen Alejandro Colomar (man-pages)
2021-07-09 16:11 ` strlen Xi Ruoyao
2021-07-10 1:00 ` strlen Segher Boessenkool
2021-07-09 10:50 ` strlen Jonny Grant
2021-07-09 11:27 ` strlen Alejandro Colomar (man-pages)
2021-07-09 11:43 ` strlen Alejandro Colomar (man-pages)
[not found] ` <1627912755.3783669.1625745946723@mail.yahoo.com>
[not found] ` <59a70222-a46f-1e65-c9db-6c9e577c8adc@126.com>
2021-07-09 17:26 ` strlen Martin Sebor
2021-07-09 20:19 ` strlen Alejandro Colomar (man-pages)
2021-07-09 20:44 ` strlen Jonny Grant
2021-07-10 18:37 ` strlen Alejandro Colomar (man-pages)
2021-07-10 20:49 ` strlen Jonny Grant
2021-07-10 21:36 ` strlen Alejandro Colomar (man-pages)
2021-07-12 21:16 ` strlen Jonny Grant
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