Boost Serialization using polymorphic archives

Question

I am working on a client-server application that uses boost::serialization library for it\'s serialization needs.

I need to serialize and deserialize polymorphic o

Answer 1

Just a few comments...

First, you can use the same operation to serialize and deserialize using a templated version:

template<class Archive>
void load(Archive & ar, const unsigned int version)
{
   ...
}

Also, instead of the macro, you can "configure" the archive to expect those types recognized as pointers:

ar.register_type(static_cast<your_static_type_here *>(NULL));

Answer 2

Found a resolution. I had to export the derived class with the statement:

BOOST_CLASS_EXPORT(derived);

Posting something that works with some corrections.

using namespace std;  

class base {  
  public:  
    int data1;  

    friend class boost::serialization::access;  

    template<typename Archive>  
    void serialize(Archive & ar, const unsigned int file_version) {  
        ar & data1;  
    }  

  public:  
    base() {};  
    base(int _d) : data1(_d) {}  
    virtual void foo() const {std::cout << "base" << std::endl;}  
};  

class derived : public base {  
  public:  
    int data2;  

    friend class boost::serialization::access;  

    template<typename Archive>  
    void serialize(Archive & ar, const unsigned int file_version) {  
        ar & boost::serialization::base_object<base>(*this);  
        ar & data2;  
    }  

  public:  
    derived() {};  
    derived(int _b, int _d) : base(_b), data2(_d) {}  
    virtual void foo() const {std::cout << "derived" << std::endl;}  
};  

BOOST_CLASS_EXPORT(derived);  

int main(int argc, char *argv[]) {  
    // client  
    // Assign to base type  
    std::unique_ptr<const base> b1(new derived(1, 2));  

    std::ostringstream oss;  
    boost::archive::text_oarchive oa(oss);  
    oa & b1.get();   

    // server  
    // Retrieve derived type from base  
    std::unique_ptr<base> b2;

    std::istringstream iss(oss.str());
    boost::archive::text_iarchive ia(iss);
    {
        base *temp; 
        ia & temp;
        b2.reset(temp);
    }
    cout << b2->data1 << endl;  
    cout << (dynamic_cast<derived*>(b2.get()))->data2 << endl;  

    return 0;  
}