Chuck Messenger wrote: [snip]
In general, the abstraction is: you have a group of intra-referential objects. When any of the group is constructed, they are all constructed (so that the master count is temporarily > 1), and the master count is reset to 1. When the master count goes to 0, the group is destructed. Hence, the group only remains alive as long as there are any external references (and as long as the intra-group references remain static).
Could a standard smart pointer be designed to encapsulate this abstraction? Hmmm....
Just FYI, this "abstraction" is the basic idea behind recoverying cycles in:
http://www.cs.kent.ac.uk/people/staff/rej/cgi-bin/searchbib?pattern=Cyclic+reference+counting+with+lazy+mark-scan.
Chrisopher's altorithm:
http://www.cs.kent.ac.uk/people/staff/rej/cgi-bin/searchbib?pattern=Christopher+Reference+count+garbage+collection
is basically the same, except the "group" is the whole heap. Christopher's is the basis of Colvin's cyclic_ptr:
http://groups.yahoo.com/group/boost/files/smart_pointers/cyclic_ptr/
Thanks -- it looks very interesting.
I did some googling, to see what its status is. Seems it hasn't been mentioned much since the flurry of activity in Jan-May 2001. Pity, since if it works "as advertised", it seems pretty useful.
- Chuck Messenger
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