Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262922AbUCKHg3 (ORCPT ); Thu, 11 Mar 2004 02:36:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262930AbUCKHg3 (ORCPT ); Thu, 11 Mar 2004 02:36:29 -0500 Received: from alt.aurema.com ([203.217.18.57]:44205 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S262922AbUCKHgZ (ORCPT ); Thu, 11 Mar 2004 02:36:25 -0500 Message-ID: <405016E2.4030208@aurema.com> Date: Thu, 11 Mar 2004 18:36:02 +1100 From: Peter Williams Organization: Aurema Pty Ltd User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Willy Tarreau CC: Linus Torvalds , root@chaos.analogic.com, linux-kernel@vger.kernel.org, "Godbole, Amarendra (GE Consumer & Industrial)" , "Randy.Dunlap" Subject: Re: (0 == foo), rather than (foo == 0) References: <905989466451C34E87066C5C13DDF034593392@HYDMLVEM01.e2k.ad.ge.com> <20040310100215.1b707504.rddunlap@osdl.org> <404F9E28.4040706@aurema.com> <20040311065041.GB14537@alpha.home.local> In-Reply-To: <20040311065041.GB14537@alpha.home.local> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2280 Lines: 51 Willy Tarreau wrote: > Hi, > > On Wed, Mar 10, 2004 at 06:36:22PM -0800, Linus Torvalds wrote: > >>And while "0 == foo" may be logically the same thing as "foo == 0", the >>fact is, the latter is what people are used to seeing. And by being used >>to seeing it, they have an easier time thinking about it. >> >>As a result, using the former just tends to increase peoples confusion by >>making code harder to read, which in turn tends to increase the chance of >>bugs. > > > I have a friend who constantly uses it, and his code is unreadable, because > sometimes, a "0 == xxx" becomes "0 <= xxx" or "0 >= xxx" which is difficult > to understand. Thinking that xxx is negative because it's written on the > right side of a >= is complicated. And the worst he does is when he uses > functions : > > if (0 < strcmp(a, "xxx")) ... > if (sizeof(t) > read(fd, t, sizeof(t)) ... > > I have already helped him track bugs in his programs, and some of them were > just related to this usage, because nobody's brain can understand these > constructions immediately without thinking a bit. So I'm all against this > sort of thing. One final note. I agree with all the statements of how awkward and unnatural the back to front boolean expressions look but I had adopted this technique (for myself) as a means of overcoming design shortcomings in the C language. I intend to keep doing it in my private code (as it's saved my bacon a number of times) but will conform to Linus's standards for any contributions/patches I submit for kernel code (just as I would conform for any other person's standards if I were to contribute to their work). In the long run, consistency in a body of code greatly enhances its readability. Peace? Peter -- Dr Peter Williams, Chief Scientist peterw@aurema.com Aurema Pty Limited Tel:+61 2 9698 2322 PO Box 305, Strawberry Hills NSW 2012, Australia Fax:+61 2 9699 9174 79 Myrtle Street, Chippendale NSW 2008, Australia http://www.aurema.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/