Date: Sun, 20 Nov 2005 17:43:47 +0100 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Colin Percival <cperciva@freebsd.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.sbin/portsnap/make_index make_index.c Message-ID: <20051120164347.GA871@eucla.lemis.com> In-Reply-To: <438046F2.60003@freebsd.org> References: <200511200050.jAK0oUbB059874@repoman.freebsd.org> <20051120080850.GD856@eucla.lemis.com> <438046F2.60003@freebsd.org>
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On Sunday, 20 November 2005 at 1:50:42 -0800, Colin Percival wrote: > Greg 'groggy' Lehey wrote: >> On Sunday, 20 November 2005 at 0:50:30 +0000, Colin Percival wrote: >>> Log: >>> An empty file does not have a positive number of lines. >> >> Yes it does. It's 0, not -0. > > As a mathematician, I must insist that 0 = -0 and is neither > positive nor negative. :-) Hmm, interesting. I've obviously forgotten too much mathematics. I've also almost forgotten ones'-complement machines, but I'm pretty sure that it's correct to say in computers that (+)0 is positive. On the ones'-complement machines I knew, -0 was also (usually) negative. >>> Make sure that the number of lines read is non-zero before in >>> order to avoid dumping core. >> >> This is a different (and presumably correct) test. > > The correct test is actually to verify that the number of lines > is positive, but while we cannot assume this (as I originally > did), we can assume that the number of lines is non-negative > (and all non-negative non-zero values are positive). Don't spoil a good story by sticking to facts :-) Greg -- See complete headers for address and phone numbers
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