Re: Using C++11

[Murray Cumming <murrayc murrayc com>]

On Tue, 2015-06-30 at 10:53 +0100, Chris Vine wrote:
> On Tue, 30 Jun 2015 08:32:43 +0200
> Murray Cumming <murrayc murrayc com> wrote:
> > On Mon, 2015-06-29 at 19:44 +0100, Chris Vine wrote:
> > [snip]
> > > Fedora 23, which will use gcc-5.1 with the new ABI, will have to
> > > recompile all its C++ binaries (libraries and programs)[1], for all
> > > versions of C++ those libraries and programs may happen to use.
> > [snip]
> >
> > And would you agree that Ubuntu (for instance) will have to do the
> > same thing when C++11 (--std=c++11) becomes the default in g++ 6,
> > when they use g++ 6?
>
> No.  Assuming gcc-6 still provides libstdc++ with both ABIs (my guess
> is that gcc will do so for a considerable number of releases), then it
> would depend on whether ubuntu chooses to use the new ABI instead of
> the old one for its C++ binaries.

Isn't Ubuntu likely to make the same choice that Fedora has made, at
least at some point?

Or is Fedora just doing this (using the C++11 libstdc++ API) because
they really like C++11 and want to make the C++11 experience as good as
possible?

> The overarching point is that this would not depend on -std=c++11
> becoming the default, because that determines the default API, not the
> ABI.
>
> On a different point, if gcc is to change the default API, then it seems
> to me more sensible that the default should be -std=c++14.


-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com