C++ ABI Issues

[Gabriel Dos Reis]

Jan Hubicka <jh@suse.cz> writes:

| On Tue, Aug 27, 2002 at 11:32:12AM -0700, Joe Buck wrote:
| > 
| > > On Mon, Aug 26, 2002 at 05:10:19PM -0700, Joe Buck wrote:
| > > > > 2. Tail-padding and virtual base classes
| > > [...]
| > > > Question: does anyone know if case 2 affects anything in libstdc++?
| > > > (e.g. iostream classes?)
| > > 
| > > No, I don't think anyone knows yet.  As soon as warnings are added to
| > > detect this kind of thing, I'll find out.  :-)
| > 
| > It seems that even if it does, we can preserve libstdc++'s binary
| > compatibility by adding a dummy field that exactly fills up any padding.
| > This will make no difference in 3.2, and will force any compiler correctly
| > implementing the ABI to match the 3.2 interface.
| 
| Sorr for jumping into discussion, but :0
| What exactly will this bring us?  libstdc++ is not only C++ library installed
| in the system and it is one of the most easilly upgardable when reinstalling
| compiler?

Yes.  Furthermore, libstdc++ has an ABI versioning both in the source
code and in the built binary.  I much prefer we use those menchanisms.

-- Gaby