Re: running 4.4 libstdc++ testsuite using 4.5's libstdc++ shared library

[Mark Mitchell <mark at codesourcery dot com>]

Paolo Carlini wrote:

> I see what you mean. But when I said experimental I meant it. We are
> talking about stuff often implemented - very partially, and in an
> unuseable way in the specific case - way before c++0x stabilized.

I understand.  I'm not criticizing the decision to implement these
features or provide them to users.  But, I do think that when we make an
incompatible change we should also change the SONAME.

There's no shame in that; the C++ run-time library specification (due in
large part to C++0x) is changing at a much more rapid rate than the C
run-time library, and C++ offers a lot more binary compatibility
problems in general, and so libstdc++ is not as compatible between
releases as GLIBC.  Users and distributors probably need to get used to
having multiple copies of libstdc++ around.  So be it.

But, I do think we should make that clear by changing the SONAME when we
are aware of an incompatible change, even to "experimental" stuff.  Or
else, we should completely disable experimental stuff in releases,
unless some special configuration option is used.  I think we shouldn't
have the experimental stuff out there in a way that people can use it
*and* change its ABI *and* not adjust the SONAME.

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713