Re: [boost] request for discussion - yet another approach to automated memory management that solves the cycles problem and is very efficient

Subject: Re: [boost] request for discussion - yet another approach to automated memory management that solves the cycles problem and is very efficient
From: Larry Evans (cppljevans_at_[hidden])
Date: 2009-02-26 20:01:03

On 02/26/09 18:07, Achilleas Margaritis wrote:
[snip]
> 3) it does not scan the graph of objects for reachability. It uses 
> simple numeric values (i.e. keys) to determine if an object can be 
> collected or not.
> 
> The idea is very simple: pointers obtain keys during their construction 
> (a simple global variable that is incremented). The key remains constant 
> throughout the lifetime of a ptr.
> 
> During pointer release, the pointers that point to an object are 
> scanned: if there is no pointer that points to the object that has a 
> lower key from the key of the releasing pointer, then the object can be 
> deleted.

Hi Achilleas.

Could you explain why this should work?  IOW, why does the test:

>> if there is no pointer that points to the object that has a 
>> lower key from the key of the releasing pointer,

assure that it's OK to delete the object?

Also, to conduct the test, it appears each pointee has to maintain
a set of pointer's to itself, which, I think, doubles the number
of pointers, i.e. if there's and edge a -> b in the pointer graph,
there most also be an edge b -> a stored in b somewhere.  Is that
right?

-regards,
Larry

[snip]