Serializing Vector of Objects which contains Vectors of Pointers

Question

I have 3 classes ("Leader", "Researchers", "Workers") which all derive from a base-class "Team".

I have a class "Project" which contains a vector of pointers to different Teams.

I use all of the following headers, in this order, in all of my class declarations:

#include <sstream>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/serialization.hpp>
#include <boost/serialization/export.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/version.hpp>
#include <boost/serialization/split_member.hpp>

To (de)serialize the Team object I use:

private:
  friend class boost::serialization::access ;

  template <typename Archive>
  void serialize(Archive& ar, const unsigned int /*version*/)
  {
      ar & teamname ;
  }

To (de)serialize the Leader, Researchers, Workers objects I use:

typedef Team _super;

friend class boost::serialization::access ;

template <typename Archive>
void serialize(Archive& ar, const unsigned int /*version*/)
{
    ar & boost::serialization::base_object<_super>(*this) ;
    ar & contactTelephoneNumber ;
}

The Project holds a std::vector of pointers to different teams and a string using:

std::vector<Team *> teams ;
std::string note ;

I use the following code in the Project class for serialization:

private:
  friend class boost::serialization::access ;

  template <typename Archive>
  void serialize(Archive& ar, const unsigned int /*version*/)
  {
      //ar & BOOST_SERIALIZATION_NVP(teams) ; //ERROR OCCURS HERE
      ar & teams;
      ar & note ;
  }

And to serialize the vector of Project objects in the main I use:

{
    std::ostringstream archiveStream ;
    boost::archive::text_oarchive archive(archiveStream) ;
    archive << BOOST_SERIALIZATION_NVP(projects) ;

    //Get serialized info as string
    archivedProjects = archiveStream.str() ;
}

This all compiles fine. The issue is at Run-Time. When the above section of the code is reached, I get the following error:

terminate called after throwing an instance of 'boost::archive::archive_exception' 
what(): 
    unregistered class - derevided class not registered or exported"

The program goes as far as:

ar & teams;

In the Questionnaire class's serialization attempt.

Answer 1

As in n.m.'s link: you need to register the classes with Boost so that it knows what classes are what when serialising.

You need to add the following line for each class where "Project" serializes:

ar.template register_type<ClassName>() ; //ClassName = Team etc