An HDS locator for the data object associated with the specified
parameter is returned. The parameter system will attempt to associate
an object if one is not already associated. In the event of a failure,
an error message will be displayed and another attempt made (usually
by prompting the user). Up to five attempts will be made, after which
status PAR__NULL will be returned.
The object will be opened with the appropriate ACCESS mode. If ACCESS
is incompatible with the access mode specified for the parameter in
the program's Interface File, status SUBPAR__ICACM will be returned.