boost serialization of struct derived from struct list

Question

I'm not sure how do i serialize a struct which derives from another struct of list type. Below is sample code of what I'm asking :

//Nodes.hpp

#include <boost/serialization/serialization.hpp>
#include <boost/serialization/access.hpp> 
#include <boost/serialization/optional.hpp> 
#include <boost/serialization/list.hpp> 

struct Node
{
      std::string firstname;
      std::string lastname;

   private:
      friend class boost::serialization::access;
      template<class Archive>
      void serialize(Archive &ar, const unsigned int version)
      {
         ar & firstname;
         ar & lastname;
      }

};

struct Nodes : public std::list<Node>
{
      std::string address;
      std::string country;

   private:
      friend class boost::serialization::access;
      template<class Archive>
      void serialize(Archive &ar, const unsigned int version)
      {
         ar & address;
         ar & country;
      }

};

BOOST_CLASS_EXPORT_KEY(Node);
BOOST_CLASS_EXPORT_KEY(Nodes);

BOOST_CLASS_EXPORT_IMPLEMENT(Nodes);         
BOOST_CLASS_IMPLEMENTATION(Nodes,boost::serialization::object_serializable);
BOOST_CLASS_TRACKING(Nodes,boost::serialization::track_never);

Please look at the line "public std::list" and let me know if my serialization is correct or not.

Answer 1

I don't know what you wanted to ask. However I do know

1. it's not recommended to inherit from standard containers (they weren't designed for this)

2. if you do, you'll still have to specify you want the base class serialized:

   struct Nodes : public std::list<Node>
   {
       std::string address;
       std::string country;
   
   private:
       friend class boost::serialization::access;
       template<class Archive>
       void serialize(Archive &ar, const unsigned int version)
       {
           ar & boost::serialization::base_object<std::list<Node> >(*this);
           ar & address;
           ar & country;
       }
   
   };
   

Of course, I'd suggest making the list a member intead of a base. Don't forget to include boost/serialization/list.hpp: see it Live On Coliru

#include <boost/serialization/serialization.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/serialization/export.hpp>
#include <boost/serialization/access.hpp>
#include <boost/serialization/base_object.hpp> 
#include <boost/serialization/optional.hpp> 
#include <boost/serialization/list.hpp> 
#include <boost/serialization/shared_ptr.hpp>
#include <list>

struct Node
{
    std::string firstname;
    std::string lastname;

    private:
    friend class boost::serialization::access;
    template<class Archive>
        void serialize(Archive &ar, const unsigned int version)
        {
            ar & firstname;
            ar & lastname;
        }

};

struct Nodes : public std::list<Node>
{
    std::string address;
    std::string country;

    private:
    friend class boost::serialization::access;
    template<class Archive>
        void serialize(Archive &ar, const unsigned int version)
        {
            ar & boost::serialization::base_object<std::list<Node> >(*this);
            ar & address;
            ar & country;
        }

};

BOOST_CLASS_EXPORT_KEY(Node);
BOOST_CLASS_EXPORT_KEY(Nodes);

BOOST_CLASS_EXPORT_IMPLEMENT(Nodes);
BOOST_CLASS_IMPLEMENTATION(Nodes    , boost::serialization::object_serializable);
BOOST_CLASS_TRACKING(Nodes          , boost::serialization::track_never);

int main()
{
    boost::archive::text_oarchive oa(std::cout);
        Nodes nodes;
        nodes.address = "Mr.";
        nodes.country = "Puerto Mazarique";
        nodes.insert(nodes.end(), Node{"John", "Doe"});
        nodes.insert(nodes.end(), Node{"Jane", "Greenwalt"});
        nodes.insert(nodes.end(), Node{"Morgan", "Cheese"});
        nodes.insert(nodes.end(), Node{"Walton", "Whiz"});

        oa << nodes;
}