programming (GC) The process by which dynamically allocated
storage is reclaimed during the execution of a program. The
term usually refers to automatic periodic storage reclamation
opposed to explicit code to free specific blocks of memory.
Automatic garbage collection is usually triggered during
memory allocation when the amount free memory falls below some
threshold or after a certain number of allocations. Normal
execution is suspended and the garbage collector is run.
There are many variations on this basic scheme.
Languages like
Lisp represent expressions as
graphs built
from
cells which contain pointers and data. These languages
expressions. During the evaluation of an expression it is
necessary to reclaim space which is used by subexpressions but
which is no longer pointed to by anything. This reclaimed
memory is returned to the free memory pool for subsequent
reallocation.
Without garbage collection the program's memory requirements
would increase monotonically throughout execution, possibly
See also the
AI koan about garbage collection.
(1997-08-25)