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Re: (not) breaking the ABI
- From: Paolo Carlini <pcarlini at suse dot de>
- To: chris jefferson <caj at cs dot york dot ac dot uk>
- Cc: libstdc++ <libstdc++ at gcc dot gnu dot org>
- Date: Wed, 25 May 2005 15:46:42 +0200
- Subject: Re: (not) breaking the ABI
- References: <42947D8B.8050502@cs.york.ac.uk>
chris jefferson wrote:
> After a brief discussion on IRC, and recent discussion on the main gcc
> mailing list, I discovered it is perhaps harder to break the ABI that
> I thought it was :)
Indeed, from some of yours sentences I got the impression that you was
overly careful ;) Traditionally, this is also my own attitude, by the
way. But since breaking the ABi bothers a lot of people and we want to
keep on improving the library it's important to know exactly -the
maximum- we can do. Let's figure it out together in detail during the
next months.
> As far as I've been able to find out, things we go into so_6 cannot:
>
> a) turn a POD into a non-POD
> b) add or remove virtual member functions of classes/structs
> c) add or remove data members of classes
> d) Change a function so does something fundamentally different, as you
> don't know which the linker will choose to pull in (you can of course
> just give your new function a new signiture and delete the old one).
>
> Out of interest, is that it? I tried looking around for a specific
> guide to what breaks ABIs and while I could find some good guides for
> C, I couldn't find one for C++.
Besides
http://gcc.gnu.org/onlinedocs/libstdc++/abi.html
you mean? Certainly the document can be improved but it's a good
starting point!
Paolo.