Re: [Boost-users] Serialization: crash atlaunchofprogram(duetoboost::serialization::base_object)

7 Apr 2006

      Robert Ramey wrote:
...
...
RIVASSEAU Jean Noel wrote:
...
Ok, I will try to send a small example to the list tomorrow. In fact
I think everything lies in the fact that using
boost::serialization::base_object also registers the fact that the
classes are parent and child. The serialization system needs to know
that in order to make casts later.
Somehow it probably does not like it when it tries to register
several different classes as the parent of the same class.
Note that there is a test test_..._mi which tests serialization with
classes which have multiple parents.  So I would hope that this
wouldn't be a problem. But you never know
Robert, the problem Jean is having is not related to multiple inheritance. 
The problem above is best described:

class version 1:
================

struct base_old{ ... };

struct derived : base_old { ... };

class version 2:
================

struct base_new{ ... };

struct derived : base_new { ... };

What would the serialize or save/load function look like to support archives 
containing version 1? I'd assume something along the lines of:

   template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    {
        if( version == 2)
        {
            ar & boost::serialization::base_object(*this);
        }
        else // while loading only
        {
            base_old lbase_old;

            ar & lbase_old;

            // update this base_new from deserialized base_old
        }
        ar & ...;
    }

I can imagine other complications if the program uses base_old pointers 
anywhere as well.

Thanks, Jeff

Re: [Boost-users] Serialization: crash atlaunchofprogram(duetoboost::serialization::base_object)

Jeff Flinn