Re: Future of libio vtable compatibility

[Carlos O'Donell <carlos@redhat.com>]

On 06/15/2018 03:50 AM, Florian Weimer wrote:
> Should we instead remove the compatibility logic altogether?

The libio vtable internal ABI compatibility has been a real source 
of pain over the years, and it has prevented the general cleanup 
of the libio code.

We learned that first hand in the malloc code during the removal of
the dump code for Emacs which also had a similar internal ABI
dependency.

However, in the case of the dumper, only emacs was known to be
affected. In the case of the vtable compat it is potentially any
number of old applications.

I'm inclined to argue that glibc 2.x should remain compatible with
the old internal ABI of the vtables, but that perhaps a future glibc
with a new major version might drop it entirely.

Should we start seriously talking about glibc 3.x?

Cheers,
Carlos.