COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

item, its appropriate size is sometimes its maximum size. For details, see OCCURS Clause for
Variable-Size Tables (page 214).
4. Reference Modifier
If the operand contains a reference modifier, the run-time routines evaluate the reference
modifier.
Unless the rules for a statement state otherwise, identification of each operand in a statement occurs
exactly once as the first operation (or series of operations) in the execution of that statement. The
identification of an operand only determines which data item is specified, it does not evaluate or
affect the content of the data item.
Overlapping Operands
When a sending and a receiving data item in a statement overlap—that is, when they share part
or all of their storage areas but are not defined by the same data description entry—the result of
the statement is undefined. Results are also undefined for some statements in which sending and
receiving data items are defined by the same data description entry. Such cases are noted in the
descriptions of those statements.
Common Phrases
These phrases are common to several different statements:
• CORRESPONDING Phrase
• ROUNDED Phrase
• SIZE ERROR Phrase
• FROM Phrase
• INTO Phrase
CORRESPONDING Phrase
For the purposes of this discussion, d1 and d2 are identifiers in a statement containing a
CORRESPONDING phrase and:
• Both d1 and d2 designate group (but not level 66) data items.
• The data description entries of d1 and d2 do not contain USAGE INDEX clauses.
• The data description entries of one or both of d1 and d2 can include REDEFINES or OCCURS
clauses or be subordinate to items whose data description entries include these clauses.
A pair of data items, one subordinate to d1 and one subordinate to d2, correspond if they follow
these rules:
• Both data items have the same data-name and the same potential set of qualifiers up to, but
not including, d1 and d2. Neither data item has the data-name FILLER.
• The data description entries of the items do not contain REDEFINES, RENAMES, OCCURS,
or USAGE INDEX clauses.
• In a MOVE statement, at least one of the data items is an elementary data item, and it is legal
to move the sending item to the receiving item.
• In an ADD or SUBTRACT statement, both items are elementary numeric data items.
If a data item does not qualify as a corresponding item, then none of its subordinates qualify either.
In Example 65, assume that the records A and H obey all of the preceding rules. The statement
MOVE CORRESPONDING A TO H
is equivalent to this series of MOVE statements:
MOVE B OF A TO B OF H
Common Phrases 243