Re: [Boost-users] [Serialization] Problem serializing viabaseclassptr

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-07-22 18:43:02

Three show stopping problems in this code:

a) A doesn't have serialize method even though
such a method is invoked by base object. see:
 http://www.boost.org/libs/serialization/doc/serialization.html

b) saving a non-const object - see rationale section

c) Main show stopper:

> int main()
> {
>     // Create a B object
>     B* Child = new B;
>
>     // Set some data
>     std::string Data = "test";
>     Child->SetValue( Data );
>
>     // Assign it to a A ptr
>     // const A* Parent = Child;  // ****** note new const - see rationale
>
>     // create and open a character archive for output
>     std::ofstream ofs( "filename" );
>
>     // save data to archive
>     {
>         try
>         {
>             boost::archive::text_oarchive oa( ofs );
>             // write class instance to archive
               // *** big problem here.  Dereferecing pointer to A yields a 
ref
               // *** to an A - regardless that ptr was a B.  What you 
really want is:
                oa << Parent; // *** let serialization handle dererencing
                // *** instead of:
>             //oa << *Parent;
>         }
>         catch( boost::archive::archive_exception& e )
>         {
>             std::cout << "Save failed! : " << e.what();
>             std::cout.flush();
>
>             return false;
>         }
>         catch( ... )
>         {
>             std::cerr << "Unknown Exception " << std::endl;
>
>             return false;
>         }
>
>     // archive and stream closed when destructors are called
>     }
>
>     delete Child;
> }
>