ABI Issues: C++ PATCH: PR 12053

[Joe Buck]

On Wed, Sep 03, 2003 at 04:16:43PM -0700, Mark Mitchell wrote:
> > In any case, we should make sure that -Wabi issues a warning for this
> > case.  The goal for -Wabi should be that if we run it using the latest
> > available GCC and it is silent, we have ABI compatibility with everything
> > from 3.2 on (barring issues with libraries).
> 
> There's no place to put such a warning -- 3.3.2 *will* be compatible
> with 3.2 (now that this fix is in), so it can't warn.  And 3.3.1 is
> already in the can, so it can't warn either.

Sure there is: 3.3.2 can warn about the problem in 3.3.1.  To know about
problems, people will have to run the check with the newest available
compiler.

In practice, -Wabi is always going to be that way: by the time we know
about an ABI compatibility, it is likely that we have already shipped the
breakage.