From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1P9L6Y-0001Qa-A9 for garchives@archives.gentoo.org; Fri, 22 Oct 2010 17:08:34 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id DFF16E08B2 for ; Fri, 22 Oct 2010 17:08:33 +0000 (UTC) Received: from mail-yx0-f181.google.com (mail-yx0-f181.google.com [209.85.213.181]) by pigeon.gentoo.org (Postfix) with ESMTP id 47192E083E for ; Fri, 22 Oct 2010 16:31:37 +0000 (UTC) Received: by yxf34 with SMTP id 34so1450113yxf.40 for ; Fri, 22 Oct 2010 09:31:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=cHrZb0qqxSl98pr9RSA95QOcqv+atGoEOx8cOzaQIgE=; b=Ke9TxNXFXbIUGfngfGC5q4dOQoh/SWc658G7DDX5LqwrXMEN3wmVnaIcb270gfTGjt 9+UCMEiPdCHPuxthK/KrL4O65Ddzavy46zAzArVK1eJNEpHjxxbYv34xrUMojcW+gBqS XNW9iNRLlfGiPhBlM+D04kzmYtjNqxIII3VBc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=ruxlSAoBicv+nBf326hMBWrI7Q8qvqEPS1ZlMIGP2ryikHOIpImD/p3bXtJBW+43P3 CLZhp7BGvGlkc50ijs6e0lp70HU09QAi5qFEG0yhoi2hUCRSfSuelmGwlYvm9sF7EK1a H0lqFaF9DdqPD7vGN9gduWKFagMtIBXXwjlls= Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.42.180.137 with SMTP id bu9mr2694947icb.34.1287765096907; Fri, 22 Oct 2010 09:31:36 -0700 (PDT) Received: by 10.42.133.1 with HTTP; Fri, 22 Oct 2010 09:31:36 -0700 (PDT) In-Reply-To: <201010212307.50617.alan.mckinnon@gmail.com> References: <201010212307.50617.alan.mckinnon@gmail.com> Date: Fri, 22 Oct 2010 09:31:36 -0700 Message-ID: Subject: Re: [gentoo-user] gcc upgrade - rebuild everything? From: Grant To: Gentoo mailing list Content-Type: text/plain; charset=ISO-8859-1 X-Archives-Salt: bdeae4ca-462d-4fb0-b6a9-cfc978c3a84a X-Archives-Hash: 1af47ddb55b83900971a09c98308db91 >> I just upgraded from gcc-4.4.3-r2 to gcc-4.4.4-r2 and I'm wondering if >> I really need to rebuild everything as it says in the guide: >> >> http://www.gentoo.org/doc/en/gcc-upgrading.xml > > No, you do not need to do this. The document is over-reaching (see below) > > I ran a mixture of 4.4.3 and 4.4.4 for ages, completely trouble-free. > >> If not, when is it necessary? > > When you have an ABI change in the code generated by the compiler. In other > words, when code generated by this version is incompatible with code generated > by that version, and you have both on the same system. This has not happened > for a long time in gcc-land. > > Now, about that official doc. Your question comes up with unbelievable > regularity and every time the poster references that doc. But it is not > necessary to do what the doc says, and a long time ago I think I figured it > out. > > The author's intention is less to give you the absolute complete total 100% > truth that will always work out just fine, and more to reduce the amount of > clutter in his inbox or on b.g.o. > > The rules about how to detect when a rebuild of world is needed are complex > and most readers simply will not understand them - they don't understand > compiler internals (how many people DO?). But if you tell people to just > rebuild world every time, and weird funny lurking problems are likely to just > get fixed as a side effect, no real harm is done. Does it hurt the author? No. > Does it reduce the amount of bugs he has to deal with on the rare occasion it > is needed? Yes. > > What does the user lose? Nothing much, more cpu cycles get used, more bits > flip on a disk, your video card gets a work out scrolling all that text. Will > you waste time? Yes. Will you break stuff? No. > > So rebuild world if it makes you feel better. But you don't need to this time. > The authors of gcc will certainly notify the entire world and it's dogs when > you do need to. Thank you everyone. I won't rebuild. - Grant