On Mon, Aug 27, 2012 at 1:48 PM, <paul_kon...@dell.com> wrote: > I'm doing some checking of data structure layouts in different releases of > our code -- which were produced by different releases of GCC (3.3.3 vs. > 4.5.4). > > One difference I'm seeing that is puzzling is in the handling of base > classes. Specifically, the case where a base class has padding at the end to > fill it out to a multiple of the alignment. > > In GCC 3.3.3, when such a class is used as a base class, that padding is > omitted, and the first derived class data member starts right after the last > base class real (not pad) data member. In GCC 4.5.4, the base class is used > padding and all, the first derived class data member starts after the padding > of the base class. > > Which is correct? Or are both correct? This sort of thing is a potential > cause of trouble if such a class is used as a container for persistent data. > > paul >
Is this message http://gcc.gnu.org/ml/gcc/2002-08/msg00874.html relevant to your case? -- Gaby