From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id CAB7D139694 for ; Thu, 20 Apr 2017 22:52:49 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id A435A21C072; Thu, 20 Apr 2017 22:52:23 +0000 (UTC) Received: from tsukuyomi.43-1.org (tsukuyomi.43-1.org [IPv6:2a01:4f8:173:743::1:50]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 5D56321C038 for ; Thu, 20 Apr 2017 22:52:23 +0000 (UTC) From: Matthias Maier To: gentoo-dev@lists.gentoo.org Subject: Re: [gentoo-dev] Re: stable gcc 5.4.0 ?? In-Reply-To: <20170420221753.GB28261@waltdnes.org> (Walter Dnes's message of "Thu, 20 Apr 2017 18:17:53 -0400") References: <20170419182551.GB19805@waltdnes.org> <20170420221753.GB28261@waltdnes.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) Date: Thu, 20 Apr 2017 17:52:20 -0500 Message-ID: <877f2eelp7.fsf@kestrel.kyomu.43-1.org> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain X-Archives-Salt: 280ddc84-b3e5-4375-901b-657026a0f4da X-Archives-Hash: fc88cca9d9d1a488856b4ea12b11b958 On Thu, Apr 20, 2017, at 17:17 CDT, "Walter Dnes" wrote: > ...fun !NOT. If you're doing a fresh install, ***WITH A GCC5-BUILT > INSTALL CD AND STAGE 3***, then yes, go for it. But changing horses in > mid-stream can be painfull. Would it hurt to stay with 4.9.4 for the > time being, assuming that you're not using prebuilt stuff like > firefox-bin or libreoffice-bin? What would be the best way to go about > it? The technical discussion how to proceed with the new C++ abi happend two years ago. We decided to do the only sensible thing in switching to the new C++ abi. (And hopefully only see very minor issues in ABI incompatibilities later on.) It unfortunately involves rebuilding parts of your userland. > A) Would 5.4.0 be slotted separately, and 4.9.4 left as the default? > B) Add "-D_GLIBCXX_USE_CXX11_ABI=0" to CFLAGS and CXXFLAGS > C) Mask out ">sys-devel/gcc-4.99" > D) Allow "--with-default-libstdcxx-abi=gcc4-compatible" via a USE flag? (A-C) gcc-5.4.0 and gcc-4.9.4 are slotted separately. What is going to be the default is entirely up to you. If overriding the ABI via (B) is such a great idea is yours to decide. (D) will definitely not happen. > Maybe we should what many enterprises do with Windows; i.e. skip a > version and go straight to gcc-6. No. We already stabilized gcc-5. A future stabilization of gcc-6/7 won't be nearly as painful as this one. There is no reason to skip something. Best, Matthias