Re: [gentoo-dev] Re: stable gcc 5.4.0 ??

[Walter Dnes]

On Thu, Apr 20, 2017 at 07:36:03AM +0200, Tomas Mozes wrote
>
> The default is new:
> https://www.gentoo.org/support/news-items/2015-10-22-gcc-5-new-c++11-abi.html

  And the news item says...

> Display-If-Installed: >=sys-devel/gcc-5

...which means that people like me, who currently have 4.9.4, won't know
about it until after the fact.  Then they'd have to...

[i660][waltdnes][~] emerge -pve @world
Total: 529 packages (3 upgrades, 526 reinstalls), Size of downloads: 10,360 KiB

...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?

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?

  Whatever option is selected, people need to be warned about it *NOW*,
not after gcc-5.4.0 has been installed.  I wonder if it's going to be
worth it to go to 5.4.  Looking at https://gcc.gnu.org/ today, I see...

GCC 5.4 Status: 2016-06-03 (regression fixes & docs only).

GCC 6.3 Status: 2016-12-21 (regression fixes & docs only). 

GCC 7.1 Status: 2017-04-20 (frozen, all changes require RM approval).

Development: GCC 8.0 Status: 2017-04-20 (regression fixes & docs only).

  Maybe we should what many enterprises do with Windows; i.e. skip a
version and go straight to gcc-6.

-- 
Walter Dnes <waltdnes@××××××××.org>
I don't run "desktop environments"; I run useful applications