For a program-described input file, input specifications describe the types of records within the file, the sequence of the types of records, the fields within a record, the data within the field, indicators based on the contents of the fields, control fields, fields used for matching records, and fields used for sequence checking. For an externally described file, input specifications are optional and can be used to add RPG IV functions to the external description.
Input specifications are not used for all of the files in your program. For some files, you must code data structures in the result field of your input operatons. The following files in your program do not use Input specifications:
Detailed information for the input specifications is given in: