From owner-freebsd-hackers@FreeBSD.ORG Mon May 5 20:09:51 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EC11E1065673 for ; Mon, 5 May 2008 20:09:51 +0000 (UTC) (envelope-from julian@elischer.org) Received: from outJ.internet-mail-service.net (outj.internet-mail-service.net [216.240.47.233]) by mx1.freebsd.org (Postfix) with ESMTP id D62698FC20 for ; Mon, 5 May 2008 20:09:51 +0000 (UTC) (envelope-from julian@elischer.org) Received: from mx0.idiom.com (HELO idiom.com) (216.240.32.160) by out.internet-mail-service.net (qpsmtpd/0.40) with ESMTP; Mon, 05 May 2008 21:11:51 -0700 Received: from julian-mac.elischer.org (localhost [127.0.0.1]) by idiom.com (Postfix) with ESMTP id 2E7732D6004; Mon, 5 May 2008 13:09:51 -0700 (PDT) Message-ID: <481F6990.9010007@elischer.org> Date: Mon, 05 May 2008 13:09:52 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.12 (Macintosh/20080213) MIME-Version: 1.0 To: Carl Shapiro References: <4dcb5abd0805050540m292b319aw52aa2cb8ba018e12@mail.gmail.com> <481F0DB3.9070505@FreeBSD.org> <481F48EE.3050806@elischer.org> <481F4EED.2030300@FreeBSD.org> <4dcb5abd0805051132o77d68e36u3f0ad38630a02afd@mail.gmail.com> In-Reply-To: <4dcb5abd0805051132o77d68e36u3f0ad38630a02afd@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org Subject: Re: binary compatibility query X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 May 2008 20:09:52 -0000 Carl Shapiro wrote: > Kris & Julian > > Thank you for clarifiying the compatibility situation. This > information was exactly what I was looking for. > > I have a follow-up question based on this remark... > > On 5/5/08, Kris Kennaway wrote: >> Actually we don't attempt to keep this form of ABI compatibility (running >> 6.3 binaries on 6.0, for example), because it basically precludes ever >> adding new functions to libc within a branch, or new syscalls to the kernel. >> You are correct that often binaries will not notice these accumulated >> changes though, or can be carefully constructed to avoid them. > > If my binary only executes system calls indirectly through libc > interfaces, as far as libc and libm are concerned, are new symbols the > only thing I need to worry about? > > Carl basically if you rely only on the standard posix interfaces and don't do anything exotic then you will "probably" be safe. the really safe way of course it to make a 6.0 chroot on your machine and compile your app there.