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 =?utf-8?Q?Kleine-K=C3=B6nig=22'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
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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 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
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