procedure GetDomainNC(o: DSName): DSName
The GetDomainNC procedure returns one of the following:
The DSName of the NC in which the object whose DSName is o is located if o is in an application partition.
The DSName of the NC that is the root for the domain where o is located if o is in a domain partition.
NULL if the NC is not found or it is not of the DN form specified in [RFC2253].