I have written code to serialize a class hierarchy (with lots of shared_ptrs, strings, vectors etc.). This compiles (and works) on gcc 4.1.2 (OpenSuse 10.3). When trying to compile it on an older machine (gcc 3.3.3) I am getting lots of compiler errors which seem to boil down to the issue the the (de)serialization code fails to instantiate some abstract class in the hierarchy. I understand that instantiating these classes has to fail, what I do not understand is why the same code compiles with gcc 4.1.2... any ideas? What I did was: I have defined the following typedefs/macros typedef boost::archive::binary_iarchive InArchive; typedef boost::archive::binary_oarchive OutArchive; #define DECLARE_AS_SERIALIZABLE \ friend class boost::serialization::access; \ void serialize(InArchive & ar, const unsigned int file_version); \ void serialize(OutArchive & ar, const unsigned int file_version) and have augmented each and every class in the hierarchy with the line DECLARE_AS_SERIALIZABLE /* inside the class */ BOOST_SERIALIZATION_SHARED_PTR(Node); /* after the class decl. */ in the .cpp file I have BOOST_CLASS_EXPORT_GUID(mepl::Node, "Node") // for each class and the implementation of the serialize methods void Node::serialize(InArchive & ar, const unsigned int /* file_version */){ ar & BOOST_SERIALIZATION_NVP(m_sFileName) //& BOOST_SERIALIZATION_NVP(m_sSource) // & BOOST_SERIALIZATION_NVP(m_parentNode) & BOOST_SERIALIZATION_NVP(m_iStartLine) & BOOST_SERIALIZATION_NVP(m_iStartColumn) & BOOST_SERIALIZATION_NVP(m_iEndLine) & BOOST_SERIALIZATION_NVP(m_iEndColumn); } void ExprNode::serialize(InArchive & ar, const unsigned int /* file_version */){ ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Node); bool bConst; ar & BOOST_SERIALIZATION_NVP(m_type) & BOOST_SERIALIZATION_NVP(bConst) & BOOST_SERIALIZATION_NVP(m_wert); m_bIsConst=bConst; } etc. As I've said, this works beautifully with gcc 4.1.2. Have I made a mistake here? Or is the older compiler not suppored in by Boost.Serialization? Small part of the compiler's output //melos/prog/boost/include/boost-1_34_1/boost/serialization/access.hpp: In static member function `static void boost::serialization::access::construct(Archive&, T*) [with Archive = boost::archive::binary_iarchive, T = mepl::Node]': //melos/prog/boost/include/boost-1_34_1/boost/serialization/serialization.hpp:105: instantiated from `void boost::serialization::load_construct_data(Archive&, T*, unsigned int) [with Archive = boost::archive::binary_iarchive, T = mepl::Node]' //melos/prog/boost/include/boost-1_34_1/boost/serialization/serialization.hpp:170: instantiated from `void boost::serialization::load_construct_data_adl(Archive&, T*, unsigned int) [with Archive = boost::archive::binary_iarchive, T = mepl::Node]' //melos/prog/boost/include/boost-1_34_1/boost/archive/detail/iserializer.hpp:308: instantiated from `void boost::archive::detail::pointer_iserializer<T, Archive>::load_object_ptr(boost::archive::detail::basic_iarchive&, void*&, unsigned int) const [with T = mepl::Node, Archive = boost::archive::binary_iarchive]' /usr/include/g++/bits/locale_facets.h:214: instantiated from here //melos/prog/boost/include/boost-1_34_1/boost/serialization/access.hpp:123: error: cannot allocate an object of type `mepl::Node' //melos/prog/boost/include/boost-1_34_1/boost/serialization/access.hpp:123: error: because the following virtual functions are abstract: node.hpp:59: error: virtual void mepl::Node::streamout(std::ostream&) const Thank you, and best regards Christoph