[boost] Serialization. Pointer to constant object.

#include <boost/archive/text_oarchive.hpp> #include <boost/serialization/serialization.hpp> using namespace boost::archive; using namespace boost::serialization; class A { friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int file_version) {} }; void f1(A const& a, text_oarchive& oa) { oa << a; } void f2(A* a, text_oarchive& oa) { oa << a; } void f3(A const* a, text_oarchive& oa) { oa << a; } Why compiled function f1 and f2 but not f3 ? Regards, Alexey.