o  Unnamed fields are similar to FILLER fields in  VAX  COBOL.   You
      can  use  them  to  format print records or to reserve space in a
      record for future additions.

   o  In a STRUCTURE field, you can use  any  field  attribute  clauses
      allowed in an elementary field.  However, if you use the DATATYPE
      field description statement, you cannot create subordinate fields
      that exceed the length of the structure field.

   o  A STRUCTURE field cannot contain the VIRTUAL FIELD datatype.

   o  Although the CDDL compiler accepts data type  specifications  for
      STRUCTURE  fields,  the  feature  can  not  be  supported  by the
      language or language processor you use with the CDD.   Make  sure
      the  definitions  you  store  in the dictionary are valid for the
      processor that will use them.

   o  All fields, except BIT fields, begin on the first byte  following
      the  preceding  field.   BIT  fields begin on the bit immediately
      following the preceding field.   You  can  modify  this  starting
      position with the ALIGNED clause.