Re: [gentoo-dev] How to support C++11 in libraries?

[Michał Górny]

Dnia 2013-12-19, o godz. 00:56:31
"C. Bergström" <cbergstrom@×××××××××.com> napisał(a):

> On 12/19/13 12:47 AM, Kent Fredric wrote:
> > On 19 December 2013 06:33, Jan Kundrát <jkt@g.o> wrote:
> >> I'm worried by the cost of such a policy, though, because we would suddenly
> >> have to patch some unknown amount of software
> >
> > Given the nature that changing that CXX Flag globally for all users
> > could cause many packages to spontaneously fail to build, wouldn't
> > that imply that changing that flag would essentially be de-stabilizing
> > the whole tree, and a package being (arch) would no longer be an
> > indication of sane, tested behaviour?
> >
> > This is really the perk of the USE driven process, the granular
> > piecemeal approach that does only as much as necessary, without
> > changing things that are already stable.
> In practice wouldn't that mean you'd have to add c++11 USE flag to every
> C++11 application and lib?

No. Only the libs that change their ABI in C++11.

> "Best case" both build and you end up with a linker problem (can be
> worked around with compiler patches)
> /usr/lib64/libboost.so
> /usr/lib64-c++11/libboost.so

What's wrong with this solution:

1. distro-specific compiler patching is wrong,

2. kinda FHS deviation, at least in spirit of lib<qual> directory.

We could go with '-L' but this is very fragile anyway. It's *very easy*
for the compiler to link the 'wrong' library due to -L/usr/lib64 being
added by some kind of foo-config.

-- 
Best regards,
Michał Górny