From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 31 Aug 2001 12:28:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 31 Aug 2001 12:27:50 -0400 Received: from [195.89.159.99] ([195.89.159.99]:41724 "EHLO kushida.degree2.com") by vger.kernel.org with ESMTP id ; Fri, 31 Aug 2001 12:27:35 -0400 Date: Fri, 31 Aug 2001 17:27:54 +0100 From: Jamie Lokier To: Roman Zippel Cc: Ion Badulescu , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [IDEA+RFC] Possible solution for min()/max() war Message-ID: <20010831172754.A25490@thefinal.cern.ch> In-Reply-To:

<20010831135034.B25128@thefinal.cern.ch> <3B8F9507.859D584F@linux-m68k.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <3B8F9507.859D584F@linux-m68k.org>; from zippel@linux-m68k.org on Fri, Aug 31, 2001 at 03:45:43PM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Roman Zippel wrote: > > 3. Warning added to GCC for signed vs. unsigned comparisons > > _regardless_ of type size. This would also catch erroneous > > unsigned char vs. EOF checks in misuses of stdio. > > Do you know of such bug in the context of min()? I don't know of an actual example. This one is made up: min (int, len, big_size) Now if big_size has unsigned type, and does not fit in the range of int, this expression will return the value of big_size cast to int, i.e. a negative value. The suggested warning would catch this potential bug. I don't know if it would warn for too many other things. Certainly, a sizeof() exception (don't warn about signed comparison with sizeof() result) is essential; perhaps too many other exceptions are required too. -- Jamie