From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35201) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QZmCp-0005cf-Sf for qemu-devel@nongnu.org; Thu, 23 Jun 2011 11:52:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QZmCn-00037h-EY for qemu-devel@nongnu.org; Thu, 23 Jun 2011 11:52:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39690) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QZmCn-00037F-29 for qemu-devel@nongnu.org; Thu, 23 Jun 2011 11:52:33 -0400 Message-ID: <4E036128.3080805@redhat.com> Date: Thu, 23 Jun 2011 18:52:08 +0300 From: Avi Kivity MIME-Version: 1.0 References: <4E023A9D.9010205@linux.vnet.ibm.com> <20110623092954.GA2682@bow.redhat.com> <4E032AC5.2080709@redhat.com> <4E035AD4.9090603@us.ibm.com> In-Reply-To: <4E035AD4.9090603@us.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] RFC: Qemu Guest Tools ISO List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: agl@linux.vnet.ibm.com, Stefan Hajnoczi , Michael Roth , "qemu-devel@nongnu.org Developers" , Anthony Liguori , pmyers@redhat.com, bsarathy@redhat.com On 06/23/2011 06:25 PM, Anthony Liguori wrote: >> Even building the tools would be very hard. In general if you build >> against libc version y, you cannot expect your code to work against libc >> version y-1, unless you take special measures. With other libraries the >> "special measures" may not even be possible. > > > Good libraries provide strong ABI compatibility. > > Something like glib clearly documents what version of the library > functions are available in, if you still to responsibly common > functions, ABI compatibility should be much of an issue. I don't know about glib, but glibc only guarantees backward compatibility, not forward compatibility. If you build against a newer glibc, your executable may not run with an older glibc, even if the symbols exist in both. See [1] which touches on the issue; I don't have a better reference. [1] ftp://ftp.kernel.org/pub/software/libs/glibc/hjl/compat/index.html -- error compiling committee.c: too many arguments to function