Gentoo Archives: gentoo-dev

From: Matthias Maier <tamiko@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] Re: stable gcc 5.4.0 ??
Date: Thu, 20 Apr 2017 22:52:49
Message-Id: 877f2eelp7.fsf@kestrel.kyomu.43-1.org
In Reply to: Re: [gentoo-dev] Re: stable gcc 5.4.0 ?? by Walter Dnes
On Thu, Apr 20, 2017, at 17:17 CDT, "Walter Dnes" <waltdnes@××××××××.org> 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

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Re: [gentoo-dev] Re: stable gcc 5.4.0 ?? Walter Dnes <waltdnes@××××××××.org>