COBOL Manual for TNS and TNS/R Programs

Data Division
HP COBOL Manual for TNS and TNS/R Programs—522555-006
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General Considerations
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SYNCHRONIZED Clause
The SYNCHRONIZED clause cannot be used for national data items.
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BLANK WHEN ZERO Clause
The BLANK WHEN ZERO clause cannot be used for national data items.
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Clauses Applying Only to Elementary Data Items
The PICTURE, SYNCHRONIZED, JUSTIFIED, and BLANK WHEN ZERO clauses
can be specified only for an elementary data item.
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Allocation of Storage
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Elementary Items
The description of an internal elementary item in the Working-Storage Section
or Extended-Storage Section causes allocation of storage space for that item
unless that item redefines another item, in which case that item shares the
redefined item’s storage space.
The description of an external elementary item causes allocation of storage
space for that item in space belonging to the run unit, outside the storage area
of any individual program. This space is shared by all programs that describe
the external data item.
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Linkage Items
The description of an elementary item in the Linkage Section does not cause
its allocation. In this case, the item is allocated by some other program, or by
the run unit, and is made available to the current program with the SET
statement or the CALL statement that causes its execution.
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Data Structures
The description of a data structure in the Working-Storage Section or
Extended-Storage Section does not cause any direct allocation, because its
data-name merely designates the combined storage spaces of all the
elementary items subordinate to it; however, the storage alignment
requirements of some elementary items can cause the generation of implicit
FILLER items whose storage space also belongs to the containing data
structures (for details, see SYNCHRONIZED Clause).
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Data Items in the File Section
Technically, the data description entries in the File Section only establish
descriptions of data items in record areas—they are not declarations in the
purest sense. If the file description does not establish a record length, the
longest data description entry associated with it does so.