Hi, I'm using MPI and I've come to an strange assertion fail from the library and I was wondering if it was "normal". Here is the code. I've got three files: header.hpp main.cpp other.cpp - - - - - - - - header.cpp - - - - - - - - #ifndef HEADER_HPP #define HEADER_HPP #include #include // Abstract class A {   friend class boost::serialization::access;   template <class Archive>     void serialize(Archive & ar, const unsigned int version) {} public:   virtual void foo() = 0; }; class B : public A {   friend class boost::serialization::access;   template <class Archive>     void serialize(Archive & ar, const unsigned int version)     {       ar & boost::serialization::base_object<A>(*this);     } public:   void foo() {} }; #endif - - - - - - - - main.cpp - - - - - - - - #include <iostream> #include #include "header.hpp" // #include // BOOST_CLASS_EXPORT(B); int main(int argc, char * argv[]) {   boost::mpi::environment env(argc, argv);   boost::mpi::communicator world;   if (world.rank() == 0)     {       A * a = new B;       world.send(1,0,a);       std::cout << "sent" << std::endl;     } } - - - - - - - - other.cpp - - - - - - - - #include "header.hpp" #include BOOST_CLASS_EXPORT(B); If I run this code I've got this assertion fail: a.out: ./boost/archive/impl/archive_pointer_oserializer.ipp:64: static const boost::archive::detail::basic_pointer_oserializer* boost::archive::detail::archive_pointer_oserializer<Archive>::find(const boost::serialization::extended_type_info&) [with Archive = boost::mpi::packed_oarchive]: Assertion `it != boost::serialization::singleton< oserializer_map<Archive>

::get_const_instance().end()' failed.

I realized that if I uncomment these lines in main.cpp: #include BOOST_CLASS_EXPORT(B); My code runs correctly. It seems that BOOST_CLASS_EXPORT needs to be in the same .cpp file (i.e main.cpp) where MPI is used. When using serialization only, BOOST_CLASS_EXPORT could be in any .cpp files. Is this normal? Also, if A is no more an abstract class, BOOST_CLASS_EXPORT(B); could be called from other.cpp and the code runs correctly. I'm using version 1.39.0. Thank you, Mathieu Larose