Hi I am getting linker errors during compilation of functions which is returning object of class boost::archive::text_iarchive. The error is "In Copy constructor 'boost::archive::basic_text_iprimitive<> ..... boost::scoped_ptr<T> is private. So I changed the scoped_ptr to public manually in the scoped_ptr.hpp file. After that I am getting an error undefined reference to boost::scoped_ptr<std::locale>. Can any body tell me how to resolve this problem. Rgds Rajeev