FDELETE returns 0 if
the operation was successful, or a nonzero number if it was not successful.
If the fileref that is specified with FDELETE is associated with a
UNIX System Services directory, PDS, or PDSE, then that directory,
PDS, or PDSE must be empty. In order to delete the directory or file,
the user that calls FDELETE must also have the appropriate privileges.