[Boost-users] [Serialize] Serialize just the base class of polymorphic pointers

Subject: [Boost-users] [Serialize] Serialize just the base class of polymorphic pointers
From: Brandon Aubie (brandon_at_[hidden])
Date: 2009-04-07 13:52:54

I have a base class BASE that stores data.  It has a virtual function
(empty in base class) that determines how this data is calculated, but
there's no data stored in the derived classes.  In my program, I'll
load a pluging that is based on BASE and implements the function to
calculate the data.  Right now I have BOOST_EXPORT_CLASS in the plugin
header files and I serialize
boost::serialization::base_object<BASE>(*this) in the derived class.
This lets me save the serialization to file just fine.

When I load it back in though, my application isn't aware of the
plugins (I'm just analyzing the data).  But I don't need the plugins,
since I just need the data.  So when I try to load in my
serialization, I get an "unregistered class" exception.  Here's how it
works

/*************** CODE ******************/

class BASE {
public:
  vector<double> data;
  virtual calculate() {};

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

class Plugin: public BASE {
public:
   virtual calculate() { /* do stuff */ }

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

BOOST_CLASS_EXPORT(Plugin)

/*************** CODE ******************/

Class Plugin is loaded dynamically at runtime via dlopen() on linux.
So I have a BASE* that points to an instance of A.  When I load in the
serialized data though, I don't really care about A and would rather
just have a BASE* that points to an instance of BASE.  Since there's
no data described in A.

Can I do this somehow?

Thanks