template<int Arity>
class RMF::CategoryD< Arity >
Data associated with nodes or sets of nodes is divided into categories. Each category is identified by a CategoryD identifier within the scope of a file as returned by FileHandle::get_category(). It is undefined behavior to pass a category from one file to another file. Typedefs (and python types are provided for single nodes, up to quads of nodes, named Category, PairCategory, TripletCategory and QuadCategory as well as typedefs for lists of them with names like Categories.
