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.

• Alexey Tourbin

• perl-Class-Singleton