Hi there, I have for a while suspected a problem with the serialization of an „enum class“ item (currently with Boost 1.61 on Ubuntu 16.04), and have written a small test program to further examine any potential problems. While the generated XML looks fine and I cannot see any problems with the enum class, my custom, free-standing „serialize“ function does not get called. It is modelled after the examples for non-intrusive serialization, so I do not understand the reason behind this. Any idea ? /*************************************/ // Compile with g++ --std=c++14 -o enum_ser -I/opt/boost/include/ -L/opt/boost/lib enum_ser.cpp -lboost_serialization #include <boost/serialization/nvp.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <iostream> #include <sstream> enum class test_enum : int {a=5,b=6}; namespace boost { namespace serialization { //----------------------------------------- template<typename Archive> void serialize(Archive &ar , test_enum &x, const unsigned int){ std::cout << "Serializing via custom serialize function" << std::endl; int t = 0; if (Archive::is_saving::value) { t = static_cast<int>(x); ar & t; } else { ar & t; x = static_cast<test_enum>(t); } } //----------------------------------------- } } int main(int argc, char **argv){ std::ostringstream oss; test_enum x = test_enum::a; { boost::archive::xml_oarchive oa(oss); oa << BOOST_SERIALIZATION_NVP(x); } std::cout << oss.str() << std::endl; } /*************************************/ Output of the program (note: the „Serializing via custom serialize function“ does not appear) : /*************************************/ <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="14"> <x>5</x> </boost_serialization> /*************************************/ Thanks and Kind Regards, Beet