You can't serialize and incomplet type. Try the following: class fd; // forward declaration class base: class derived { ..... fd *ptr; ..... friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version); { (void) file_version; ar & ptr; ar & boost::serialization::base_object<derived>(*this); } }; //end of class base In a *.cpp file #include "fd.h" template<class Archive> void base::serialize(Archive & ar, const unsigned int file_version); { ar & ptr; ar & boost::serialization::base_object<derived>(*this); } Robert Ramey "niranjan bangera" wrote in message news:50a2f6f20901112119p631960d5ncc524bec7beef22@mail.gmail.com... hi all, i have done in the following way.. even am getting some errors, did i miss any of the headers, or added extra(added extra for sure). Any suggestions will be accepted #include #include #include #include #include <fstream> #include #include #include class fd; class base: class derived { ..... fd *ptr; ..... friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { (void) file_version; ar & ptr; ar & boost::serialization::base_object<derived>(*this); } }; //end of class base Version::1.36.0 compliler: g++ 4.1.1.... i am getting a error : error: forward declaration of 'struct fd' /boost_1_36_0/include/boost-1_36/boost/serialization/access.hpp:109: error: inva lid use of undefined type 'struct /project/wipro_virtutech_nobackup/users/niranjan/project_new/boost_1_36_0/include/boost-1_36/boost/serialization/extended_type_info_typeid.hpp:117: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined. Thanks in advance..... ------------------------------------------------------------------------------ _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users