In general, an identifier for an NDF section can be passed without error to any routine which will accept an equivalent identifier referring to a base NDF. In certain cases, however, the behaviour of the routine may differ slightly when an NDF section is supplied in order to adhere to two guiding principles:
The set of operations affected by these principles is rather small because most NDF components (e.g. label, units, title, history and extensions) are regarded as global and are equally accessible via identifiers referring to NDF sections and base NDFs. It is mainly operations on array components which behave differently when applied to NDF sections, and notably those which affect the attributes of these components. For instance, the numeric type of an NDF array component cannot be changed using NDF_STYPE (§) via a section identifier; instead, this routine will simply return without action. Neither may an NDF be deleted (§) via a section identifier.
These, and other differences, are noted in the appropriate routine
descriptions in Appendix and at other relevant
points in this document.