This position is used to identify a data structure or data-structure subfield
as externally described. If a data structure or subfield is not being defined
on this specification, then this field must be left blank.
Entry
Explanation for Data Structures
E
Identifies a data structure as externally described: subfield definitions
are defined externally. If the EXTNAME keyword is not specified, positions
7-21 must contain the name of the externally described file containing the
data structure definition.
Blank
Program described: subfield definitions for this data structure follow
this specification.
Entry
Explanation for Subfields
E
Identifies a data-structure subfield as externally described. The specification
of an externally described subfield is necessary only when keywords such as
EXTFLD and INZ are used.
Blank
Program described: the data-structure subfield is defined on this specification
line.