Structure inheritance and tail padding

Hi all,

just from observation I arrived to the unconfirmed conclusion that
Structure inheritance adds tail padding. For example:

class A(Structure):
  _fields_ = [('a', c_double), ('b', c_char)]

class B(A):
  _fields_ = [('c', c_int)]

will not show the same layout than:

class C(Structure):
  _fields_ = [('a', c_double), ('b', c_char), ('c', c_int)]

Supposing my conclusion is right, what is the intention of this feature:

i. To support c++ pod subclassing? (most compilers reuse the tail
padding for non-pod subclassing).

ii. To support a more oo view of c struct composition? (btw, it
complements the ms-extensions very well).

Thank you in advance
--
Carlos

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