From owner-freebsd-current@FreeBSD.ORG Sun Aug 15 15:26:55 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 705E016A4CE; Sun, 15 Aug 2004 15:26:55 +0000 (GMT) Received: from itchy.rabson.org (mailgate.nlsystems.com [80.177.232.242]) by mx1.FreeBSD.org (Postfix) with ESMTP id A9C3B43D1D; Sun, 15 Aug 2004 15:26:54 +0000 (GMT) (envelope-from dfr@nlsystems.com) Received: from ns0.nlsystems.com (ns0.nlsystems.com [80.177.232.243]) by itchy.rabson.org (8.12.11/8.12.11) with ESMTP id i7FFQoeN073050; Sun, 15 Aug 2004 16:26:50 +0100 (BST) (envelope-from dfr@nlsystems.com) From: Doug Rabson To: "Justin T. Gibbs" Date: Sun, 15 Aug 2004 16:27:03 +0100 User-Agent: KMail/1.6.2 References: <200408151611.04764.dfr@nlsystems.com> In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200408151627.03820.dfr@nlsystems.com> X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on itchy.rabson.org X-Virus-Scanned: clamd / ClamAV version 0.75.1, clamav-milter version 0.75c on itchy.rabson.org X-Virus-Status: Clean cc: Daniel Eischen cc: Johan Pettersson cc: Stefan Ehmann cc: freebsd-current@freebsd.org Subject: Re: New nvidia drivers available X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 15 Aug 2004 15:26:55 -0000 On Sunday 15 August 2004 16:16, Justin T. Gibbs wrote: > >> I thought that static constructor invocation was deterministic > >> based on link order. Does the C++ spec really indicate that the > >> order of construction can be random? > > > > I don't think the spec places any restrictions on constructor > > ordering. The problem here is that you get different behaviour > > depending on whether you link with libGL first followed by > > libpthread (in that case libpthread initialises first) or if you > > link in the other order (in which case libGL initialises first). As > > far as I can see, rtld calls the _init sections of each shared > > library in reverse order with the last library linked against being > > initialised first. > > But such ordering restrictions also apply to things like weak > symbols, so I don't think that imposing a link order restriction to > solve this issue is really a problem. The algorithm for weak symbols is pretty simple - you always get either the first strong symbol that rtld finds in its search or the last weak symbol. I think we arrange for stuff like open(2) to be weak in libc and strong in libpthread. > > >From my Microsoft days, I know that at least PowerPoint took > > advantage > > of the known order of static constructor invocation. The splash > screen was executed from a static constructor in the first .o linked > into the executable. I'm just curious if this is something the C++ > spec says anything about. I'd be surprised if it didn't. I'm sure that constructor ordering differs between binutils toolchains on unix systems and Microsoft toolchains on win32 systems. The software I write in my day job uses C++ constructors heavily and I'm certain that things get constructed in a different order on the two platforms. We just accept it and write code that can initialise in any order.