From: Andreas Schwab <schwab@redhat.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-kernel@vger.kernel.org, Michael Buesch <mb@bu3sch.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] strcmp: fix overflow error
Date: Tue, 17 Nov 2009 18:36:41 +0100 [thread overview]
Message-ID: <m3lji5xdcm.fsf@hase.home> (raw)
In-Reply-To: <1258476700-21323-1-git-send-email-u.kleine-koenig@pengutronix.de> ("Uwe Kleine-König"'s message of "Tue, 17 Nov 2009 17:51:40 +0100")
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> writes:
> strcmp("\x01", "\xef") returns 18 but it should return something < 0.
> The reason is that the variable holding the result of the subtraction is
> too small and overflows.
When char is signed strcmp("\xef", "\x01") still returns something < 0.
You need to cast to unsigned char first.
Andreas.
--
Andreas Schwab, schwab@redhat.com
GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84 5EC7 45C6 250E 6F00 984E
"And now for something completely different."
next prev parent reply other threads:[~2009-11-17 17:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-17 16:51 [PATCH] strcmp: fix overflow error Uwe Kleine-König
2009-11-17 17:36 ` Andreas Schwab [this message]
2009-11-17 17:41 ` Linus Torvalds
2009-11-17 18:16 ` Michael Buesch
2009-11-17 18:40 ` Linus Torvalds
2009-11-17 20:34 ` Andreas Schwab
2009-11-17 18:55 ` Uwe Kleine-König
2009-11-17 19:02 ` Linus Torvalds
2009-11-17 19:12 ` Linus Torvalds
2009-11-17 19:19 ` Joe Perches
2009-11-18 21:31 ` [PATCH] strcmp: fix overflow and possibly signedness error Uwe Kleine-König
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m3lji5xdcm.fsf@hase.home \
--to=schwab@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mb@bu3sch.de \
--cc=torvalds@linux-foundation.org \
--cc=u.kleine-koenig@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.