Rob Stewart wrote:
I contend that you can provide a mechanism whereby clients can ensure their type can only be instantiated by the Singleton framework, but don't require that.
I already do :) You can use a type deriving from the singleton if you want true singleton behavior, or you can use a typedef if you want one globally managed resource and any number of local resources. class A : public singleton < A > { /*...*/ }; // only the singleton instance can exist class B { /*...*/ }; // can create any number of B instances typedef singleton < B > global_b; // but global_b manages the lifetime of one global B instance. There is a multiton for cases when you need multiple global instances that uses key based identification, and alternately you can derive a different type from B for each global instance you want managed. class Printer { /*...*/ }; class PrinterA : public Printer, public singleton < PrinterA > { }; class PrinterB : public Printer, public singleton < PrinterB > { }; -Jason