Cloning Identifiers

Since an NDF identifier only refers to an NDF data structure and is not itself a data structure, it is possible to have several identifiers referring to the same NDF. A duplicate identifier for an NDF may be derived from an existing one by a process called cloning, which is performed by the routine NDF_CLONE, as follows:

      CALL NDF_CLONE( INDF1, INDF2, STATUS )

This returns a second identifier INDF2 which refers to the same NDF data structure as INDF1.

Cloning is not required frequently, but it can occasionally be useful in allowing an application to ``hold on'' to an NDF when an identifier is passed to a routine which will annul it; i.e. you simply pass the original identifier and keep the cloned copy. An example of this can be found in the section on matching NDF attributes (§).