COPY statements in the copybook
You can base your XOM on a COBOL copybook that contains COPY statements or references other copybooks that contain COPY statements.
When you generate the BOM from a copybook, you import the main
copybook. If the main copybook contains no COPY statements,
the COBOL importer just generates the XOM.
If the copybook contains one or more COPY statements,
the COBOL importer merges the contents of each nested copybook file
into the main copybook and generates one XOM entry. For this type
of copybook, you must make sure that all the nested copybooks are
defined in the system library path of the COBOL importer, otherwise
the COBOL importer reports an error.