I-O-CONTROL paragraph
The
I-O-CONTROL paragraph of the input-output section specifies when checkpoints are
to be taken and the storage areas to be shared by different files. This
paragraph is optional in a COBOL program.
The keyword I-O-CONTROL can appear only once, at the beginning of the
paragraph. The word I-O-CONTROL must begin in Area A and must be followed by a
separator period.
The order in which I-O-CONTROL paragraph clauses are written is not
significant. The I-O-CONTROL paragraph ends with a separator period.
| Format: Sequential I-O-control entries |
 >>-+-RERUN--+----+--+-assignment-name-1-+--+-------+--| phrase 1 |------------------------+-><
| '-ON-' '-file-name-1-------' '-EVERY-' |
+-SAME--+--------+--+------+--+-----+--file-name-3--+-----------------+----------------+
| '-RECORD-' '-AREA-' '-FOR-' | .-------------. | |
| | V | | |
| '---file-name-4-+-' |
| .--------------------------------------. |
| (1) V | |
+-MULTIPLE FILE-------+------+--+----------+----file-name-5--+---------------------+-+-+
| '-TAPE-' '-CONTAINS-' '-POSITION--integer-2-' |
| .-------------. |
| (1) V | |
'-APPLY WRITE-ONLY-------+----+----file-name-2-+---------------------------------------'
'-ON-'
phrase 1:
|--+-integer-1--RECORDS----+--+----+--file-name-1---------------|
'-END--+----+--+-REEL-+-' '-OF-'
'-OF-' '-UNIT-'
|
Notes:
- The MULTIPLE FILE clause and APPLY WRITE-ONLY clause are syntax checked, but have no effect on the execution of the program.
| Format: Relative and indexed I-O-control entries |
 >>-+-RERUN--+----+--+-assignment-name-1-+--+-------+--| phrase 1 |---------+-><
| '-ON-' '-file-name-1-------' '-EVERY-' |
'-SAME--+--------+--+------+--+-----+--file-name-3--+-----------------+-'
'-RECORD-' '-AREA-' '-FOR-' | .-------------. |
| V | |
'---file-name-4-+-'
phrase 1:
|--integer-1--RECORDS--+----+--file-name-1----------------------|
'-OF-'
|
| Format: Line-sequential I-O-control entries |
 .-------------.
V |
>>---SAME--+--------+--+------+--+-----+--file-name-3----file-name-4-+---><
'-RECORD-' '-AREA-' '-FOR-'
|
| Format: Sort/merge I-O-control entries |
 >>-+----------------------------------+------------------------->
'-RERUN--+----+--assignment-name-1-'
'-ON-'
.-------------------------------------------------------.
V |
>----SAME--+-RECORD-----+--+------+--+-----+--| phrase 1 |-+---><
+-SORT-------+ '-AREA-' '-FOR-'
'-SORT-MERGE-'
phrase 1:
|--file-name-3--+---------------------+-------------------------|
| .-----------------. |
| V | |
'---+-------------+-+-'
'-file-name-4-'
|
|