Internal Program Version: Class::Singleton  1.600.0.5.42.0

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.

http://search.cpan.org/dist/Class-Singleton