From owner-freebsd-standards@FreeBSD.ORG  Sun Sep  5 19:56:54 2004
Return-Path: <owner-freebsd-standards@FreeBSD.ORG>
Delivered-To: freebsd-standards@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 16E2016A4CE
	for <freebsd-standards@freebsd.org>;
	Sun,  5 Sep 2004 19:56:54 +0000 (GMT)
Received: from bgezal.rise.tuwien.ac.at (bgezal.rise.tuwien.ac.at
	[128.130.59.74])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 9ABD743D53
	for <freebsd-standards@freebsd.org>;
	Sun,  5 Sep 2004 19:56:49 +0000 (GMT)
	(envelope-from stefan@fafoe.narf.at)
Received: from fafoe.narf.at (unknown [212.186.3.235])
	by bgezal.rise.tuwien.ac.at (Postfix) with ESMTP id A803620A2;
	Sun,  5 Sep 2004 21:56:47 +0200 (CEST)
Received: from wombat.fafoe.narf.at (wombat.fafoe.narf.at [192.168.1.42])
	by fafoe.narf.at (Postfix) with ESMTP
	id 62F9740EE; Sun,  5 Sep 2004 21:56:41 +0200 (CEST)
Received: by wombat.fafoe.narf.at (Postfix, from userid 1001)
	id 165ECDC; Sun,  5 Sep 2004 21:56:38 +0200 (CEST)
Date: Sun, 5 Sep 2004 21:56:38 +0200
From: Stefan Farfeleder <stefan@fafoe.narf.at>
To: Steve Kargl <sgk@troutmask.apl.washington.edu>
Message-ID: <20040905195632.GG72545@wombat.fafoe.narf.at>
Mail-Followup-To: Steve Kargl <sgk@troutmask.apl.washington.edu>,
	freebsd-standards@freebsd.org
References: <20040905193640.GA37190@troutmask.apl.washington.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20040905193640.GA37190@troutmask.apl.washington.edu>
User-Agent: Mutt/1.5.6i
cc: freebsd-standards@freebsd.org
Subject: Re: is printf() broken?
X-BeenThere: freebsd-standards@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Standards compliance <freebsd-standards.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-standards>,
	<mailto:freebsd-standards-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-standards>
List-Post: <mailto:freebsd-standards@freebsd.org>
List-Help: <mailto:freebsd-standards-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-standards>,
	<mailto:freebsd-standards-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 05 Sep 2004 19:56:54 -0000

On Sun, Sep 05, 2004 at 12:36:40PM -0700, Steve Kargl wrote:
> The following program
> 
> #include <stdio.h>
> int main(void) {
> 	int d;
> 	double x;
> 	x = 1.234E05;
> 	for (d = 0; d < 5; d++)
>     	printf("%+-31.*e\n", d, x);
> 	return 0;
> }
> 
> generates
> 
> +1e+05                         
> +1.2e+05                       
> +1.23e+05                      
> +1.234e+05                     
> +1.2340e+05                    
> 
> The question is whether the first number should be
> "+1.e+05".  That is, is the printing of the decimal
> point required or optional?  I only have Harbison
> and Steele's book and it does not state what the 
> expected behavior should be.

The output is correct:

e, E   A double argument representing a floating-point number is converted in the
       style [-]d.ddd eħdd, where there is one digit (which is nonzero if the
       argument is nonzero) before the decimal-point character and the number of
       digits after it is equal to the precision; if the precision is missing, it is taken as
       6; if the precision is zero and the # flag is not specified, no decimal-point
       character appears. The value is rounded to the appropriate number of digits.
[...]

Cheers,
Stefan