[boost] Re: shared_ptr and serialization

From: Peter Petrov (ppetrov_at_[hidden])
Date: 2004-11-18 04:27:14

Gennadiy Rozental <gennadiy.rozental <at> thomson.com> writes:

> Here we do very simple (or complex,depends on point of view) trick instead
> of above
> Let say we have somewhere map<T*,shared_ptr<T>*> registry;
> 
>     if( registry[raw_ptr] == 0 ) {
>        t = shared_ptr<T>( raw_ptr )
>        registry.add( raw_ptr, &t );
>     }
>     else
>         t = *registry[raw_ptr];
> 
> >     // current shared_ptr implementation depends upon an internal pointer
> to
> > a shared count.
> > }
> 
> Do I miss something important?

What happens when some time after deserialization, one of the deserialized
shared_ptr's is destroyed? Your "registry" has no way to know that and will
still hold a shared_ptr referencing the same object, which is not correct.