NDG_ROOTPROV - Identify the root ancestors in a provenance structure

Description:

This routine searches the supplied provenance structure for root ancestors, and returns information about them. An ancestor is a root ancestor if it does not itself have any ancestors.

Invocation:

CALL NDG_ROOTPROV( IPROV, KM, STATUS )

Arguments:

IPROV = INTEGER (Given)

An identifier for a structure holding the provenance information read from an NDF, as returned by NDG_READPROV.

KM = INTEGER (Returned)

A pointer to an AST KeyMap containing an entry for each root ancestor. The key associated with each entry is the path to the NDF and the value of the entry is an integer that gives the position of the root ancestor within the list of all ancestors. This integer value can be supplied to ndgGetProv in order to get further information about the root ancestor. The first ancestor NDF has an index of one. An index of zero refers to the NDF from which the provenance information was read.

STATUS = INTEGER (Given and Returned)

The global status.