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- Description:
The routine returns an NDF placeholder. A placeholder is used
to identify a position in the underlying data system
(HDS) and
may be passed to other routines (e.g. NDF_NEW) to indicate where
a newly created NDF should be positioned.
- Invocation:
CALL NDF_PLACE( LOC, NAME, PLACE, STATUS )
- Arguments:
-
LOC = CHARACTER * ( * ) (Given)
-
HDS locator to the structure to
contain the new NDF.
-
NAME = CHARACTER * ( * ) (Given)
-
Name of the new structure component (i.e. the NDF).
-
PLACE = INTEGER (Returned)
-
NDF placeholder identifying the nominated position in the
data system.
-
STATUS = INTEGER (Given and Returned)
-
The global status.
- Notes:
-
Placeholders are intended only for local use within an
application and only a limited number of them are available
simultaneously. They are always annulled as soon as they are
passed to another routine to create a new NDF, where they are
effectively exchanged for an NDF identifier.
-
The value given for the NAME argument may be an HDS path name,
consisting of several fields separated by '.', so that an NDF can
be created in a sub-component (or a sub-sub-component...) of the
structure identified by the locator LOC. Array subscripts may
also be used in this component name. Thus a string such as
'MYSTRUC.ZONE(2).IMAGE' could be used as a valid
NAME value.
-
Normally, this routine will be used as the basis for creating
a completely new NDF data structure. However, if the LOC and NAME
arguments refer to a pre-existing object, then this structure
will be used as the basis for the new NDF. An object which is to
be used in this way must be an empty scalar structure with an HDS
type of 'NDF'.
-
A new NDF can be created within an explicitly named container
file by supplying the symbolic value DAT__ROOT for the LOC
argument, and specifying the container file within the value
supplied for the NAME argument. If the object is the top level
object within a container file, then a new container file is
created. If it is not a top level object, then the container file
and all structures lying above the object should already exist.
-
If a blank value is given for the NAME argument, then the new
NDF will be the object identified directly by the locator LOC.
This must be an empty scalar structure of type 'NDF'.
-
If this routine is called with STATUS set, then a value of
NDF__NOPL will be returned for the PLACE argument, although no
further processing will occur. The same value will also be
returned if the routine should fail for any reason.
-
The NDF__NOPL constant is defined in the include file NDF_PAR.
The DAT__ROOT constant is defined in the include file DAT_PAR
(see SUN/92).
Next: NDF_PROP - Propagate NDF information to create a new NDF via the ADAM parameter system
Up: FORTRAN ROUTINE DESCRIPTIONS
Previous: NDF_OPEN - Open an existing or new NDF
Starlink User Note 33
R.F. Warren-Smith
11th January 2000
E-mail:rfws@star.rl.ac.uk
Copyright © 2000 Council for the Central Laboratory of the Research Councils