From owner-freebsd-questions@FreeBSD.ORG  Mon Jan  5 20:47:03 2009
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id B91221065704
	for <freebsd-questions@freebsd.org>;
	Mon,  5 Jan 2009 20:47:03 +0000 (UTC)
	(envelope-from patfbsd@davenulle.org)
Received: from smtp.lamaiziere.net (net.lamaiziere.net [91.121.44.19])
	by mx1.freebsd.org (Postfix) with ESMTP id 7D8EC8FC1D
	for <freebsd-questions@freebsd.org>;
	Mon,  5 Jan 2009 20:47:03 +0000 (UTC)
	(envelope-from patfbsd@davenulle.org)
Received: from baby-jane.lamaiziere.net (246.10.87-79.rev.gaoland.net
	[79.87.10.246])
	by smtp.lamaiziere.net (Postfix) with ESMTPA id E0A70633692;
	Mon,  5 Jan 2009 21:47:01 +0100 (CET)
Received: from baby-jane-lamaiziere-net.local (localhost [127.0.0.1])
	by baby-jane.lamaiziere.net (Postfix) with ESMTP id CD13B697169;
	Mon,  5 Jan 2009 21:47:00 +0100 (CET)
Date: Mon, 5 Jan 2009 21:46:59 +0100
From: Patrick =?ISO-8859-15?Q?Lamaizi=E8re?= <patfbsd@davenulle.org>
To: freebsd-questions@freebsd.org, Edward King <zhangsc@neusoft.com>
Message-ID: <20090105214659.125f55a2@baby-jane-lamaiziere-net.local>
In-Reply-To: <022201c96f07$553b65a0$3f83a8c0@user863c0bf569>
References: <022201c96f07$553b65a0$3f83a8c0@user863c0bf569>
Organization: /dave/nulle
X-Mailer: Claws Mail 3.3.1 (GTK+ 2.12.9; i386-apple-darwin9.3.0)
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-15
Content-Transfer-Encoding: 8bit
Cc: 
Subject: Re: why printf() don't work?
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 05 Jan 2009 20:47:04 -0000

Le Mon, 05 Jan 2009 15:29:23 +0800,
Edward King <zhangsc@neusoft.com> a écrit :

> I use FreeBSD7.0,and use signal,like follows:
> signal(SIGHUP,sig_hup);
> signal(SIGIO,sig_io);
> 
> when I run call following code,it can run,but I find a puzzled
> question,it should print some information,such as printf("execute
> main()") will print execute main(),but in fact,printf fuction print
> none!!! Why printf function do not go work?

Just to be sure :
You should not use printf() in a signal handler, it is not
considered 'signal safe'.
(See man sigaction)

Regards.