Long-term plan for C++98/C++11 incompatibility

[Jeffrey Yasskin]

On Mon, Oct 10, 2011 at 5:07 PM, Gabriel Dos Reis
<gdr@integrable-solutions.net> wrote:
> On Mon, Oct 10, 2011 at 5:25 PM, Joe Buck <Joe.Buck@synopsys.com> wrote:
>> On Fri, Oct 07, 2011 at 07:35:17PM -0700, Gabriel Dos Reis wrote:
>>> C++11 is essentially binary incompatible with C++98.
>>
>> Only partially.  The layout for user-defined classes is the same, and
>
> PODness has changed from C++98.

Sorry for digging this up months later, but this caught my eye. I've
heard several people strongly claim that the core ABI didn't change,
and here you seem to be contradicting them. Can you give a concrete
example of a user-defined class that doesn't use any standard library
features but changes layout between C++98 and C++11 when compiled with
gcc?

Thanks,
Jeffrey