Re: Smart pointer status, directions, thoughts

From: williamkempf_at_[hidden]
Date: 2001-05-26 10:04:09

--- In boost_at_y..., "Peter Dimov" <pdimov_at_m...> wrote:
> From: <williamkempf_at_h...>
> 
> > > OK. Do you agree that it is a real problem? How would you solve 
it?
> > (I mean
> > > the problem with serializing a shared_ptr.)
> >
> > Using the same techniques I'd use if raw pointers were being used
> > instead.
> 
> Raw pointers can't be serialized in the general case. You don't 
know whether
> the pointer owns the object.

Every persistence library I've used serializes raw pointers (at least 
such pointers to serializesable objects).

> > Seriously, the example given is a very non-trivial example
> > and knowing if an object has been previously serialized is not 
going
> > to be enough info to persist the containing object any way.
> 
> It's enough info for me:
> 
> int last_id = 0;
> std::map<shared_ptr_id, int> m;

This right above is the extra "database" I referred to.  Knowing if 
an object had been previously serialized was not enough, you had to 
track more in the object identity in order to be able to recreate the 
web on reading.

Bill Kempf