From owner-freebsd-standards@FreeBSD.ORG Thu Jan 8 21:57:12 2009 Return-Path: Delivered-To: freebsd-standards@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 164AF106566B; Thu, 8 Jan 2009 21:57:12 +0000 (UTC) (envelope-from v.haisman@sh.cvut.cz) Received: from service1.sh.cvut.cz (service1.sh.cvut.cz [IPv6:2001:718:2::214]) by mx1.freebsd.org (Postfix) with ESMTP id 6ACE58FC0A; Thu, 8 Jan 2009 21:57:11 +0000 (UTC) (envelope-from v.haisman@sh.cvut.cz) Received: from localhost (localhost [127.0.0.1]) by service1.sh.cvut.cz (Postfix) with ESMTP id 960DA124086; Thu, 8 Jan 2009 22:57:09 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at service1.sh.cvut.cz X-Spam-Score: -87.588 X-Spam-Level: X-Spam-Status: No, score=-87.588 tagged_above=-255 required=5 tests=[ALL_TRUSTED=-1.44, AWL=14.852, CRM114_HAM_00=, SMTPAUTH_SHDOMAIN=-100] Received: from service1.sh.cvut.cz ([127.0.0.1]) by localhost (service1.sh.cvut.cz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nQNiertStr-G; Thu, 8 Jan 2009 22:57:01 +0100 (CET) Received: from [192.168.1.2] (35.201.broadband4.iol.cz [85.71.201.35]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: v.haisman@sh.cvut.cz) by service1.sh.cvut.cz (Postfix) with ESMTP id B12B4124085; Thu, 8 Jan 2009 22:57:01 +0100 (CET) Message-ID: <496676AB.9040905@sh.cvut.cz> Date: Thu, 08 Jan 2009 22:56:59 +0100 From: =?UTF-8?B?VsOhY2xhdiBIYWlzbWFu?= User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) MIME-Version: 1.0 To: Bruce Evans , Vaclav Haisman , imp@FreeBSD.ORG, freebsd-gnats-submit@FreeBSD.ORG, freebsd-standards@FreeBSD.ORG References: <200812302231.mBUMVUtf092910@www.freebsd.org> <20081231215445.S3923@delplex.bde.org> <20090106190313.GA15233@zim.MIT.EDU> In-Reply-To: <20090106190313.GA15233@zim.MIT.EDU> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Subject: Re: standards/130067: Wrong numeric limits in system headers? X-BeenThere: freebsd-standards@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Standards compliance List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Jan 2009 21:57:12 -0000 David Schultz wrote, On 6.1.2009 20:03: > On FreeBSD/i386, long doubles are represented with 64 bits of > precision, but computations are performed with 53 bits of > precision. In a sane world, this discrepancy wouldn't exist, but > for reasons I won't get into, they do, and probably always will. > > C99 defines the LDBL constants based on what can be represented, > not what can be computed as the result of arithmetic operations, > so my interpretation is that the values in float.h are correct, > though confusing. I am not language lawyer but even if it were true that the constants are right, there is still the problem that they (especially the LDBL_MAX value) are useless with the provided GCC. Either GCC or the headers should be changed. Otherwise the constants are rather useless and unusable. -- VH