Hi, I am currently experimenting with writing a compiler tool which generates the code necessary for using boost::serialization. While working on this I found that I am unable to serialize a variable declaration which is a reference to a class constructed with the default constructor '()'( ex. class foo var(); ). I have tried to find an explanation for this in the examples, documentation and through searching the web without success. Using pointers it works fine with the default constructor and I do not see why it should be any different for references (as references in essence are pointers). Is it possible to serialize a class constructed using the default constructor using boost::serialization, and if so how? Example: #include <fstream> // include headers that implement a archive in simple text format #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> class gps_set { friend class boost::serialization::access; public: int x; gps_set::gps_set(){ x = 2;}; virtual gps_set::~gps_set(){}; gps_set::gps_set(int i) : x(1) {}; private: template<typename Archive> void serialize(Archive& ar, const unsigned int version){ ar& x; }// End method: X::serialization }; int main() { // save the schedule std::ofstream ofs("filename"); // create class instance //Compile time error if s1() is used. No error if s1(1) is used. const gps_set s1(); // save data to archive { boost::archive::text_oarchive oa(ofs); // write class instance to archive oa << s1; // archive and stream closed when destructors are called } }; Thanks, Andreas Saebjoernsen