REDEFINES clause

The REDEFINES clause allows the same computer storage area to be described by different data description entries.

General format

Level-Number [Data-Name-1] [ REDEFINES Data-Name-2 ]              [FILLER     ]

NOTE - Level-Number, Data-Name-1, and FILLER are shown in the above format to improve clarity. Level-Number, Data-Name-1, and FILLER are not part of the REDEFINES clause.

Syntax rules

1.	Level-Number of Data-Name-2 and Level-Number of the item being described must be identical.

2.	This clause must not be used in level 01 entries in the File Section.

3.

The data description entry for Data-Name-2 cannot contain an OCCURS clause. However, Data-Name-2 may be subordinate to an item whose data description entry contains an OCCURS clause. In this case, the reference to Data-Name-2 may not be subscripted. Neither the original definition nor the redefinition can include a variable occurrence data item.

4.

If the data item referenced by Data-Name-2 is either declared to be an external data record or is specified with a level number other than 01, the number of character positions it contains must be greater than or equal to the number of character positions in the data item referenced by the subject of this entry. If the data name referenced by Data-Name-2 is specified with a level number of 01 and is not declared to be an external data record, there is no such constraint.

5.	Data-Name-2 must not be qualified even if it is not unique since no ambiguity of reference exists in this case because of the required placement of the REDEFINES clause within the source program.

6.	The entries giving the new description of the character positions must not contain any VALUE clauses, except in subordinate condition-name entries.

7.	No entry having a level number numerically lower than the level number of Data-Name-2 and the subject of the entry may occur between the data description entries of Data-Name-2 and the subject of the entry.

8.	The entries giving the new descriptions of the character positions must follow the entries defining the area of Data-Name-2, without intervening entries that define new character positions.

9.	Data-Name-2 may be subordinate to an entry which contains a REDEFINES clause.

General rules

1.	Storage allocation starts at Data-Name-2 and continues over a storage area sufficient to contain the number of character positions in the data item referenced by Data-Name-1 or the FILLER clause.

2.	When the same character position is defined by more than one data description entry, the data-name associated with any of those data description entries can be used to reference that character position.