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Re: Plans for ABI migration
- To: Joe Buck <jbuck at racerx dot synopsys dot com>
- Subject: Re: Plans for ABI migration
- From: Andi Kleen <ak at suse dot de>
- Date: 10 Jan 2001 14:06:15 +0100
- Cc: gcc at gcc dot gnu dot org
- References: <200101092116.NAA10679@racerx.synopsys.com>
Joe Buck <firstname.lastname@example.org> writes:
> Bernardo Innocenti writes:
> > did the steering comitee already set a roadmap to ease the
> > migration from the old C++ ABI (gcc 2.9x) to the new one
> > (gcc 3.x)?
> No, because there is nothing special about an ABI change with a
> major release of the compiler. Some background:
> In the past, the C++ ABI broke with every major release. egcs 1.0
> was different from 2.7.x. egcs 1.1 was different from egcs 1.0.
> gcc 2.95 was different from egcs 1.1. Red Hat's "2.96" is
In my experience egcs 1.0 / egcs 1.1 / 2.95 were not really incompatible
for "basic C++" (no exceptions, no RTTI, no STL, minor use of the C++
standard library, no multiple inheritance). Most C++ programs (e.g. Qt)
only seem to use a similar subset so it wasn't that a big a problem
to e.g. link an older Qt to a egcs 1.1 program. IIRC e.g. the changes
between 1.1 and 2.95 were only in some rather obscure parts.
With gcc 3 that will change though because the vtables are completely
different and I guess a better migration strategy would make sense.
At least please make sure that it fails at link time, not with strange