From owner-freebsd-bugs  Tue Aug 20 10:42:14 2002
Delivered-To: freebsd-bugs@hub.freebsd.org
Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 7B5F437B400
	for <freebsd-bugs@hub.freebsd.org>; Tue, 20 Aug 2002 10:42:11 -0700 (PDT)
Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21])
	by mx1.FreeBSD.org (Postfix) with ESMTP id CD77543E84
	for <freebsd-bugs@hub.freebsd.org>; Tue, 20 Aug 2002 10:42:10 -0700 (PDT)
	(envelope-from gnats@FreeBSD.org)
Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1])
	by freefall.freebsd.org (8.12.4/8.12.4) with ESMTP id g7KHfvJU080994
	for <freebsd-bugs@freefall.freebsd.org>; Tue, 20 Aug 2002 10:41:57 -0700 (PDT)
	(envelope-from gnats@freefall.freebsd.org)
Received: (from gnats@localhost)
	by freefall.freebsd.org (8.12.4/8.12.4/Submit) id g7KHffec080988;
	Tue, 20 Aug 2002 10:41:41 -0700 (PDT)
Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 7D45937B400
	for <freebsd-gnats-submit@FreeBSD.org>; Tue, 20 Aug 2002 10:32:56 -0700 (PDT)
Received: from www.freebsd.org (www.FreeBSD.org [216.136.204.117])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 3F70143E42
	for <freebsd-gnats-submit@FreeBSD.org>; Tue, 20 Aug 2002 10:32:56 -0700 (PDT)
	(envelope-from nobody@FreeBSD.org)
Received: from www.freebsd.org (localhost [127.0.0.1])
	by www.freebsd.org (8.12.4/8.12.4) with ESMTP id g7KHWtOT034153
	for <freebsd-gnats-submit@FreeBSD.org>; Tue, 20 Aug 2002 10:32:55 -0700 (PDT)
	(envelope-from nobody@www.freebsd.org)
Received: (from nobody@localhost)
	by www.freebsd.org (8.12.4/8.12.4/Submit) id g7KHWtKV034152;
	Tue, 20 Aug 2002 10:32:55 -0700 (PDT)
Message-Id: <200208201732.g7KHWtKV034152@www.freebsd.org>
Date: Tue, 20 Aug 2002 10:32:55 -0700 (PDT)
From: GOTO Kentaro <gotoken@notwork.org>
To: freebsd-gnats-submit@FreeBSD.org
X-Send-Pr-Version: www-1.0
Subject: bin/41823: printf("%+f\n", -0.0) generates +0.000000
Sender: owner-freebsd-bugs@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-bugs.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-bugs>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-bugs>
X-Loop: FreeBSD.org


>Number:         41823
>Category:       bin
>Synopsis:       printf("%+f\n", -0.0) generates +0.000000
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Aug 20 10:40:28 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     GOTO Kentaro
>Release:        STABLE and CURRENT
>Organization:
>Environment:
FreeBSD 5.0-CURRENT i386

>Description:
vfprintf() generates a wrong "+" sign for a floating point number 
minus zero, i.e., -0.0, when +[eEfgG] is specified in the format.  

>How-To-Repeat:
% echo 'main(){printf("%+f\\n", -0.0);}' | /usr/bin/cc -xc - && ./a.out
+0.000000
      

>Fix:
How about Checking sign bit instead of `< 0'. 

For example, NetBSD's /usr/src/lib/libc/stdio/vfprintf.c:cvt() does 

        digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
        if (dsgn) {
                value = -value;
                *sign = '-';
        } else
                *sign = '\000';

But FreeBSD's does

        if (value < 0) {
                value = -value;
                *sign = '-';
        } else
                *sign = '\000';

This test does not work in this case because IEEE754 defines the 
truth value of -ZERO < ZERO as FALSE. 

>Release-Note:
>Audit-Trail:
>Unformatted:

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-bugs" in the body of the message