From owner-svn-src-all@FreeBSD.ORG Thu Jan 17 18:41:01 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 277806E2; Thu, 17 Jan 2013 18:41:01 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from bigwig.baldwin.cx (bigknife-pt.tunnel.tserv9.chi1.ipv6.he.net [IPv6:2001:470:1f10:75::2]) by mx1.freebsd.org (Postfix) with ESMTP id 03DE094B; Thu, 17 Jan 2013 18:41:01 +0000 (UTC) Received: from pakbsde14.localnet (unknown [38.105.238.108]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 5C99DB9B8; Thu, 17 Jan 2013 13:41:00 -0500 (EST) From: John Baldwin To: d@delphij.net Subject: Re: svn commit: r245494 - head/bin/pwait Date: Thu, 17 Jan 2013 13:40:35 -0500 User-Agent: KMail/1.13.5 (FreeBSD/8.2-CBSD-20110714-p22; KDE/4.5.5; amd64; ; ) References: <201301160503.r0G53qie087155@svn.freebsd.org> <201301161111.49580.jhb@freebsd.org> <50F71D5E.60604@delphij.net> In-Reply-To: <50F71D5E.60604@delphij.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201301171340.35912.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Thu, 17 Jan 2013 13:41:00 -0500 (EST) Cc: "svn-src-head@freebsd.org" , Eitan Adler , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , Xin LI X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jan 2013 18:41:01 -0000 On Wednesday, January 16, 2013 4:36:30 pm Xin Li wrote: > On 01/16/13 08:11, John Baldwin wrote: > > On Wednesday, January 16, 2013 1:49:40 am Xin LI wrote: > >> This doesn't seem right -- you should never release memory before > >> exit, especially for memory allocated in main(), unless this > >> "main" is intended for different purpose like a monolithic shell > >> that wants to avoid exec(). Note that pwait(1) have multiple exit > >> points I don't think it's practical. > >> > >> Would you mind if I commit this changeset instead? I have the > >> return -> exit change in my queue long ago but only noticed it > >> today... > > > > I think the free shouldn't be there as well, but I think requiring > > an exit() instead of return to "fix" it is bogus as well. The > > static analyzer is just broken in this case. main() is special and > > returns from it should be treated like exit() and not cause false > > warnings about memory leaks. > > Well, being a horrible idea itself to redefine main() to something > else and expect the module to do no harm to its caller, I think Eitan > still have a valid point that it could be a bad idea to ban this in > wholesale within compiler, as the C standard don't ban using return's > in main(). As I said in a later followup, I think there should be an option, but it should default to treating return from main as exit(). > In style(9) the examples do use exit() for main() by the way. Yes, but as other folks have pointed out, return() can be more suitable in other cases (specifically with C++ when you want objects in scope to be properly destroyed). -- John Baldwin