Re: [gentoo-dev] impending c++11 clusterfuck?

[Mikhail Korolev]

2015-11-30 7:10 GMT+03:00 C Bergström <cbergstrom@×××××××××.com>:
>
> On Mon, Nov 30, 2015 at 10:56 AM, Gregory M. Turner <gmt@×××××××.net> wrote:
> > I'm quoting myself from bug #566328 here.  These were off-the-cuff
> > remarks that got away from me and became a call-to-arms...
> >
> > (In reply to Michał Górny from comment #7)
> >> This is never this simple. C++11 can change the ABI. So the point kinda is,
> >> we need to ensure that all C++ libraries in a depgraph use the same C++
> >> version.
> >
> > This is pretty awful when you really think about it.  I feel like I'm
> > watching a train-wreck in super slow motion.
> >
> > I'm not sure we're taking this seriously enough -- sooner or later it
> > seems destined to become a major clusterfuck if we don't do something
> > proactive about it now while the drawing-board is relatively
> > uncluttered.
> >
> > The only thing I can think of that has this kind of two-way depgraph
> > magic property are the major "abi" USE_EXPAND values (multilib-build
> > and python-r1, in other words).
> >
> > But those rely on fancy framework-generated USE-flag deps, which seem
> > like overkill and likely to incur unjustifiable user-experience-costs.
> >
> > Perhaps a solution to this cxx11 clusterfuck can be found that works
> > more like perl?  By that I mean, pick your poison (respectively, your
> > cxx11 ABI of preference or your major perl version of choice), rely on
> > inbuilt portage features do the trick most of the time, and, when it
> > breaks, run "magically-fix-everything.sh," grab a caffeinated beverage
> > or three and fire up your favorite VOD client while the mess gets
> > magically cleaned up by robots somehow.
>
> I'm not sure I fully understand the problem, but what about
> a. Always define the c++11 flag
> b. Not support a system with mixed (and incompatible) c++ standards
>
> I personally don't think it seems reasonable to try to carry both
> c++03 and c++11 at the same time. This especially seems like nonsense
> to me in the gentoo world. gcc has or will soon switch to c++11 by
> default. Packages which can't be built will start having issues
> anyway.
>

But there are such packages.
```
 [ ~ ] # grep "=c++11" /etc/portage/make.conf
CXXFLAGS="${CFLAGS} -std=c++11"
 [ ~ ] # cat /etc/portage/package.env
sys-libs/libcxx clang
sys-libs/libcxxrt clang

media-gfx/blender cxxflags_std-gnupp11
dev-qt/qtwebkit:4 cxxflags_std-cpp03
kde-base/kdelibs:4 cxxflags_std-cpp03
media-video/vlc cxxflags_std-gnupp11

 [ ~ ] # ls -d1 /var/db/pkg/*/* | wc -l
1294
```