The Linkage Section is used to define data items that are passed from a calling program.
General Format
LINKAGE SECTION.
[ record-description ] ...
General Rules
- Each level 01 and 77 data item described in Linkage must be uniquely named.
- Subordinate data names need not be unique if they can be made unique through qualification.
- Each level 01 and 77 data item declared in Linkage should be named in a USING phrase of the Procedure Division header. Data
items that are REDEFINES of other data items should not be named, however.
- There is a limit of 255 level 01 Linkage data items per program. There is no limit for the number of subordinate items allowed
for each of these level 01 items.
Note: There are two runtime configuration variables that relate to linkage items:
CHECK_USING for specifying parameter size-matching testing; and
OPTIMIZE_INDIVIDUAL_LINKAGE that perform address optimizations on each Linkage item individually.