From owner-freebsd-doc@FreeBSD.ORG  Mon Feb 11 05:04:48 2013
Return-Path: <owner-freebsd-doc@FreeBSD.ORG>
Delivered-To: freebsd-doc@freebsd.org
Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115])
 by hub.freebsd.org (Postfix) with ESMTP id E839DDF6
 for <freebsd-doc@freebsd.org>; Mon, 11 Feb 2013 05:04:48 +0000 (UTC)
 (envelope-from erichsfreebsdlist@alogt.com)
Received: from alogt.com (alogt.com [69.36.191.58])
 by mx1.freebsd.org (Postfix) with ESMTP id 9B40174F
 for <freebsd-doc@freebsd.org>; Mon, 11 Feb 2013 05:04:48 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=alogt.com;
 s=default; 
 h=Content-Transfer-Encoding:Content-Type:Mime-Version:Message-ID:Subject:To:From:Date;
 bh=5q/0Mnne4/Udh+EcRX+Ed1BKAqv0zMAoUp5dzx/3Bf4=; 
 b=akfgwbRwXLLZAdJfkILAiHRn1mMOT8lbhJyH3vzK5xG6GU0J/9WJFPrhmMvQFEGAjvIgII1WxuZr3d9xDY+KblH+AMOCc7bV+cbG3pb0D0w+TKlg++SDv63BWLH9NGQL;
Received: from [122.129.203.50] (port=60147 helo=X220.ovitrap.com)
 by sl-508-2.slc.westdc.net with esmtpsa (SSLv3:DHE-RSA-AES128-SHA:128)
 (Exim 4.80) (envelope-from <erichsfreebsdlist@alogt.com>)
 id 1U4lZJ-003FkD-Rs
 for freebsd-doc@freebsd.org; Sun, 10 Feb 2013 22:04:42 -0700
Date: Mon, 11 Feb 2013 12:04:38 +0700
From: Erich Dollansky <erichsfreebsdlist@alogt.com>
To: freebsd-doc@freebsd.org
Subject: missing information in man 3 system
Message-ID: <20130211120438.730ce5d3@X220.ovitrap.com>
X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.6; amd64-portbld-freebsd10.0)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
X-AntiAbuse: This header was added to track abuse,
 please include it with any abuse report
X-AntiAbuse: Primary Hostname - sl-508-2.slc.westdc.net
X-AntiAbuse: Original Domain - freebsd.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - alogt.com
X-Get-Message-Sender-Via: sl-508-2.slc.westdc.net: authenticated_id:
 erichsfreebsdlist@alogt.com
X-Source: 
X-Source-Args: 
X-Source-Dir: 
X-BeenThere: freebsd-doc@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Documentation project <freebsd-doc.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-doc>,
 <mailto:freebsd-doc-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-doc>
List-Post: <mailto:freebsd-doc@freebsd.org>
List-Help: <mailto:freebsd-doc-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-doc>,
 <mailto:freebsd-doc-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 11 Feb 2013 05:04:49 -0000

Hi,

man 3 system says:

RETURN VALUES

The system() function returns the exit status of the shell as returned
by waitpid(2), or -1 if an error occurred when invoking fork(2) or
waitpid(2). A return value of 127 means the execution of the shell
failed.

It seems to me that one part is missing here. I made two small test
programs:

Program 1 in error.c

int main (void)
{
   return 0x1;
}

Program 2 in show result:

int main (void)
{
   printf ("Return code: %i\n", system ("error"));
   return 0
}

This results in

Return code: 256

being displayed.

system () returns the result from 'error.c' in the result but shifted
by 8 bits to the left.

I could not find this behaviour in the FreeBSD documentation.

So, is this the intended behaviour of system ()?

Should the documentation be uptdated?

Or did I simply miss something?

Erich