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Date: Sat, 4 Aug 2001 14:44:39 -0400
From: Mike Barcroft <mike@FreeBSD.org>
To: Bruce Evans <bde@zeta.org.au>
Cc: audit@FreeBSD.org
Subject: Re: cmp(1) warns patch
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In-Reply-To: <20010804124551.S16377-100000@besplex.bde.org>; from bde@zeta.org.au on Sat, Aug 04, 2001 at 12:59:56PM +1000
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On Sat, Aug 04, 2001 at 12:59:56PM +1000, Bruce Evans wrote:
> On Fri, 3 Aug 2001, Mike Barcroft wrote:
> > ...
> > Index: cmp/regular.c
> > ===================================================================
> > RCS file: /home/ncvs/src/usr.bin/cmp/regular.c,v
> > retrieving revision 1.10
> > diff -u -r1.10 regular.c
> > --- cmp/regular.c	2000/06/20 20:28:40	1.10
> > +++ cmp/regular.c	2001/08/04 01:02:33
> > ...
> > @@ -81,7 +81,7 @@
> >  	off2 = ROUNDPAGE(skip2);
> >
> >  	length = MIN(len1, len2);
> > -	if (length > SIZE_T_MAX)
> > +	if (length > (off_t)SIZE_T_MAX)
> 
> This is broken on many machines, including alphas.  On alphas,
> (off_t)SIZE_MAX overflows to -1, so `length' is always larger and the
> pessimized cspecial() method is always used.
> 
> Casting the left hand size to the type of the right hand side would be
> even more broken.
> 
> Without any casts, `length' and SIZE_T_MAX were promoted to a common
> type and there was no problem unless length < 0 (which can't happen).

I guess I should have looked at the types a little more closely.  Do
you have any suggestions for overcoming the comparison between signed
and unsigned warning on alpha?

Best regards,
Mike Barcroft

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