Using Files with External-Description as Program-Described

A file created from external descriptions can be used as a program-described file in the program. To use an externally described file as a program-described file,

1. Specify the file as program-described (F in position 22) in the file description specification of the program.
2. Describe the fields in the records on the input or/and output specifications of the program, or as subfields of a data structure.

At compile time, the compiler uses the data structure you have defined, or the field descriptions in any input or/and output specifications that you coded for the file. It does not retrieve the external descriptions.