Indicates the beginning of the record structure declaration and
  defines the name of the structure.  Declaration format:

     STRUCTURE [/str/][fnlist]
       fdcl
       [fdcl]
       ...
       [fdcl]
     END STRUCTURE

     str     Identifies a structure name, which is used in
             subsequent RECORD statements to refer to the
             structure. A structure name is enclosed in slashes.

     fnlist  Identifies field names when used in a substructure
             declaration.(Only allowed in nested structure
             declarations.)

     fdcl    (Also called the declaration body.)  Is any
             declaration or combination of declarations of
             substructures, unions, or typed data, or
             PARAMETER statements.

  Subsequent RECORD statements use the structure name to refer to the
  structure.  A structure name must be unique among structure names,
  but structures can share names with variables (scalar or array),
  record fields, PARAMETER constants, and common blocks.

  Structure declarations can be nested (contain one or more other
  structure declarations).  A structure name is required for the
  structured declaration at the outermost level of nesting, and
  optional for the other declarations nested in it.  However, if you
  wish to reference a nested structure in a RECORD statement in your
  program, it must have a name.

  Structure, field, and record names are all local to the defining
  program unit.  When records are passed as arguments, the fields
  must match in type, order, and dimension.

  Unlike type declaration statements, structure declarations do not
  create variables.  Structured variables (records) are created when
  you use a RECORD statement containing the name of a previously
  declared structure.  The RECORD statement can be considered as a
  kind of type declaration statement.  The difference is that
  aggregate items, not single items, are being defined.

  Within a structure declaration, the ordering of both the statements
  and the field names within the statements is important because this
  ordering determines the order of the fields in records.

  In a structure declaration, each field offset is the sum of the
  lengths of the previous fields.  The length of the structure,
  therefore, is the sum of the lengths of its fields.  The structure
  is packed; you must explicitly provide any alignment that is needed
  by including, for example, unnamed fields of the appropriate
  length.

  By default, fields are aligned on natural boundaries; misaligned
  fields are padded as necessary.  To avoid padding of records, you
  should lay out structures so that all fields are naturally aligned.

  To pack fields on arbitrary byte boundaries, you must specify a
  compiler option.  You can also specify alignment for fields by
  using the cDEC$ OPTIONS general directive.

  In the following example, the declaration defines a structure named
  DATE.  This structure contains three scalar fields:  DAY
  (LOGICAL*1), MONTH (LOGICAL*1), and YEAR (INTEGER*2).

     STRUCTURE /DATE/
         LOGICAL*1  DAY, MONTH
         INTEGER*2  YEAR
     END STRUCTURE

  See also COMPATIBILITY_FEATURES RECORD_STRUCTURE in this Help file.