One final consideration may apply if multiple applications are to be
invoked from a single program (as in the example in
§) but some ``global'' NDF data structures
are required to remain in use between applications. This is not a common
requirement, but since default history recording is normally initiated
only by the action of releasing an NDF, it will not occur in such a
situation, so the global datasets will not automatically receive
history information. To overcome this problem, a call to NDF_HEND may
be used at the end of each application, as follows:
CALL NDF_HEND( STATUS )
This notifies the NDF_ system that the current application has
finished. It causes default history information to be written, if
required, to all NDFs currently in use and ensures that new
history records will be created to contain any history
information
written subsequently (i.e. by the next application). NDF_HEND
then revokes any ``current application'' name established via the
NDF_HAPPN routine (see §).
If its STATUS argument indicates an error condition, NDF_HEND also
records the STATUS value and pending error message information in any
suitable history components belonging to NDFs currently in
use, as described in §.