The file description comprises information concerning the physical structure, identification, and record-names pertaining to a given file.
It determines the internal or external attributes of a file connector, of the associated data records, and of the associated data items. The file description entry also determines whether a file-name is a local name or a global name.
General Formats for Format 1 (Record Sequential Files)
General Formats for Format 2 (Line Sequential Files)
General Formats for Format 3 (Relative and Indexed Files)
General Formats for Format 4 (Sort-Merge Files)
Syntax Rules for All Formats (All Files)
- The clauses which follow file-name-1 may appear in any order.
- If the VALUE OF FILE-ID clause is specified, literal-1 must be a nonnumeric literal and cannot be a figurative constant.
Syntax Rules for Formats 1, 2 and 3 (RecordSequential,
Line Sequential, Relative and Indexed Files)
- The level indicator FD identifies the beginning of a file description and must precede the file-name.
- One or more record description entries must follow the file description entry.
- The EXTERNAL clause and the THREAD-LOCAL clause must not be specified in the same file description entry.
Syntax Rules for Format 4 (Sort-Merge Files)
- The level indicator SD identifies the beginning of the sort-merge file description and must precede the file-name.
- The clauses which follow the name of the file are optional and may appear in any order.
- One or more record description entries must follow the sort-merge file description entry. However, no input-output statements can be executed for this file.
General Rules for Format 1 (Record Sequential Files)
- If the file description entry for a sequential file contains the LINAGE clause and the EXTERNAL clause, the LINAGE-COUNTER data item is an external data item. If the file description entry for a sequential file contains the LINAGE clause and the GLOBAL clause, the special register LINAGE-COUNTER is a global name.
