Re: [boost] Re: Re: shifted_ptr<> w/ lock mechanism

From: Larry Evans (jcampbell3_at_[hidden])
Date: 2003-01-30 18:25:06

Philippe A. Bouchard wrote:
[snip]
 >
 > Oh no, don't tell me GC_malloc was working this way ;)
 >
 > BTW gc_header *must* have (ip_descriptor *) ?
 > 	
        
Only if you want to collect cycles or provide some other means for
accessing the arcs in the pointer graph.  As a matter of fact, it may
be better to do somewhat like shared_ptr does, i.e. instead of storing
a ip_descriptor*, just store something like counted_base, where the
actual instance is a derived class, counted_impl<T>, which knows the
"real" type, T, of the object pointed to.  Maybe just add another
virtual function to descriptor_of<T>, which does what the virtual
counted_base_impl<P,D>::dispose does.  This would allow proper
destruction without a virtual destructor.  IOW, the ip_descriptor* in
the gc_header substitutes for the virtual destructor.  This is pretty
much of the top of my head, so, take it for what it's worth.