This is the Class::Singleton module. 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. This module
implements a Singleton class from which other classes can be
derived. 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.
