reference counting
A {garbage collection} technique where each {memory cell} contains a count of the number of other cells
which point to it. If this count reaches zero the cell is
freed and its {pointers} to other cells are followed to
decrement their counts, and so on {recursively}.
This technique cannot cope with {circular data structures}.
Cells in such structures refer (indirectly) to themselves and
so will never have a zero reference count. This means they
would never be reclaimed, even when there are no references
from outside the structure.
(1995-02-22)