Re: [Boost-users] [serialization] How to serialize an object using areference to its base class ?

From: x y (nosferatu_1_1_at_[hidden])
Date: 2006-09-28 05:42:42

It works now, but only with XML archives. When I serialize into a binary archive I get a std::exception "bad alloc exception thrown".

I forgot to mention that I'm working with Borland C++ Builder 6, boost 1_33_0

I also tried with gcc 3.2.3 on linux with boost 1_33_1 and it also works only with xml archives. With binary archive I get a "basic_string::resize" exception.

Robert Ramey <ramey_at_[hidden]> wrote:       This works for pointers - not references. - the  following - along with compatible changes - should work.
  
 Robert Ramey
  
 void serialize(const base_class * src,  std::ostream& dest) {
    boost::archive::binary_oarchive  oa(dest);
    oa <<  BOOST_SERIALIZATION_NVP(src);
}

    "x y" <nosferatu_1_1_at_[hidden]> wrote in    message news:20060927081505.10666.qmail_at_web31012.mail.mud.yahoo.com...
Hi,

I'm new to boost and I'm having some    trouble serializing an object using a reference to its base    class.

Although there are a lot of messages related to this topic in    the newsgroups and the doc, I did not find a workable answer to my proplem.    

In the following code, the function serialize takes a reference to    base_class as parameter. But the serialize method of derived_class is never    called.

Did I miss something ?

Thanks for your    help
Marc

#include <string>
#include    <sstream>
#include <iostream>

#include    <boost/archive/binary_oarchive.hpp>
#include    <boost/archive/binary_iarchive.hpp>
#include    <boost/serialization/string.hpp>
#include    <boost/serialization/access.hpp>
#include    <boost/serialization/is_abstract.hpp>
#include    <boost/serialization/export.hpp>

using namespace    std;

class base_class {
    friend class    boost::serialization::access;
   
       public:
        base_class() :    my_string("") { };
           base_class(string s) : my_string(s) {    };
        virtual ~base_class()    {};

        virtual void foo(void) =    0;

        template<class    Archive>
        void    serialize(Archive & ar, const unsigned int    version)
           {
            ar    &    BOOST_SERIALIZATION_NVP(my_string);
           }

       public:
        string    my_string;
};

BOOST_IS_ABSTRACT(base_class);
BOOST_CLASS_EXPORT(base_class);

class    derived_class : public base_class {
    friend class    boost::serialization::access;

       public:
        derived_class() :    base_class(), my_int(0) {};
           derived_class(string s, int i) : base_class(s), my_int(i)    {};
        virtual ~derived_class()    {};

        void foo(void)    {};

        template<class    Archive>
        void    serialize(Archive & ar, const unsigned int    version)
           {
            ar    &    BOOST_SERIALIZATION_BASE_OBJECT_NVP(base_class)
                  &    BOOST_SERIALIZATION_NVP(my_int);
           }

        int    my_int;
};

BOOST_CLASS_EXPORT(derived_class);

void    serialize(const base_class& src, std::ostream& dest)    {
    boost::archive::binary_oarchive    oa(dest);
    oa <<    BOOST_SERIALIZATION_NVP(src);
}

int main(int argc, char** argv)    {
    try {
           std::stringstream ss;

           derived_class d("aaa", 5);
        cout    << "before: " << d.my_string << " " << d.my_int    << endl;
        serialize(d,    ss);

        //    deserialize
        derived_class    d2;
           boost::archive::binary_iarchive    ia(ss);
        ia >>    d2;
        cout << "after: "    << d2.my_string << " " << d2.my_int <<    endl;
    }
    catch (const    std::exception& ex) {
        cout    << "std exception: " << ex.what() <<    endl;     }
    catch (...)    {
        cout << "unknown    exception" << endl;           
    }
}

      

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