Sorry. Posted in haste, and I forgot a critical paragraph. With those structures, also try seeing what they do when you remove each of 'x' and 'y' in turn. Specifically, does 'z' continue to be in the same location? In the SPECIFIC example of a single default integer in a sequence type, it will a rare compiler that lays it out differently. But all of the INTEGER, INTEGER BIND(C), sequence type and derived type without the SEQUENCE may have different sizes and alignments. And, on SOME systems, a pointer to one of those may not be usable as a pointer to another.