When I want to serialise a vector of shared ptrs to concrete types, there are no warnings on gcc/Linux. and program runs correctly. However when I compile on HP-UX, I get the following: .../boost_1_39_0/boost/serialization/export.hpp", line 137: warning #2414-D: delete of pointer to incomplete class BOOST_STATIC_WARNING(boost::is_polymorphic<T>::value); .... It appears that boost shared ptr serialisation has made the assumption that the pointer must be polymorphic! Is this assumption correct ? i.e are we allowed to serialize shared ptrs to concrete types ? To get rid of the message I simply add a virtual member function. It appears in this case that HPUX compiler is more accurate, and I don't understand why this same warning does not appear with gcc. Best regards, Ta, Avi