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Date: Tue, 28 Apr 2009 13:55:10 +0200
From: Olivier Houchard <mlfbsd@ci0.org>
To: Gavin Atkinson <gavin@freebsd.org>
Message-ID: <20090428115510.GA98699@ci0.org>
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Cc: Channa <channa.kad@gmail.com>, freebsd-arm@freebsd.org
Subject: Re: strncmp issue
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> On Tue, 2009-04-28 at 15:22 +0530, Channa wrote:
> > Hi,
> > 
> > I am using the freebsd implementation of strncmp for ARM which is an
> > assembly implementation.
> > I have a small doubt, when i tested the strncmp by passing the third argument:
> > 'n' as -1 the return values is  '0' instead it should '-1'.
> > When the third argument  to strncmp is as below:
> > 
> > ret = strncmp("a","b",-1)
> > 
> > I think the assembly implementation in
> > src/lib/libc/arm/string/strncmp.S file needs
> > to be modified to take care of the above condition.
> > 
> > In the current implementation
> > /* if ((len - 1) < 0) return 0 */
> >         subs    r2, r2, #1
> >         movmi   r0, #0
> >         RETc(mi)
> > 
> > This should be changed to check as below
> > 
> > /* if ((len ) < 0) return 0 */
> > /* Assembly code here */
> > 
> > Could anyone help in solving the above issue.?
> > 

Hi,

This shouldn't be an issue, as the second argument of strncmp is unsigned,
-1 is not a valid value.

Regards,

Olivier