|unsigned int||get_index () const|
This template class provides a unique index, i.e. an unique unsigned integer number for all instances of the (derived) class. A new index for the object is created whenever a call to 'get_index()' is issued the first time. The assigned index is removed from the list of assigned indices if the object is destroyed. Please note that the index of temporary objects is deleted from the list of indices, even it is assigned to another object. The class T must have two static member functions, 'get_typename()' and 'get_max_instances()' to return a unique label and the maximum number of instances per class, respectively.