The class::singleton module implements a singleton class from which other classes can be derived. a singleton describes an object class that can have only one instance in any system. an example of a singleton might be a print spooler or system registry.

by itself, the class::singleton module does very little other than manage the instantiation of a single object. in deriving a class from class::singleton, your module will inherit the singleton instantiation method and can implement whatever specific functionality is required.

for a description and discussion of the singleton class, see "design patterns", gamma et al, addison-wesley, 1995, isbn 0-201-63361-2.