gcc3 ABI compatibility?

[Ian Lance Taylor]

Michael VanLoon <michaelv@yahoo-inc.com> writes:

> On 6/5/08 7:15 AM, "Ian Lance Taylor" <iant@google.com> wrote:
>
>> Andrew Haley <aph@redhat.com> writes:
>> 
>>> Probably.  The multi-vendor C++ ABI made this a lot better, but there are
>>> still incompatibilities.  We don't break ABI compatibility on release
>>> branches,
>>> so you can safely assume that 3.4.2 is compatible with 3.4.1.
>> 
>> And across release branches, it is worth knowing about the
>> -fabi-version option.
>> 
>> Ian
>
> That's very cool!  I notice that gcc 4.0.1 (Darwin) gives the option of
> versions 0 through 2, where 2 is gcc 3.4 ABI version.  Does this mean that
> gcc 4 uses the ABI from gcc 3.4?

Yes.

> Would this mean a library built with gcc
> 3.4.6, containing non-templatized C++ class interfaces, would successfully
> link into code built with gcc 4, especially if I specified -fabi-version=2?

Yes.

Ian