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

Libraries and Utility Routines
HP COBOL Manual for TNS/E Programs—520347-003
13-26
COBOL_CONTROL_
cpinfo
is a checkpoint list in which the routine records the changes to the message
storage data space, for example:
01 CP-LIST-1.
05 MAX-COUNT PIC 9999 COMP VALUE IS 100.
05 CURRENT-COUNT PIC 9999 COMP VALUE IS 0.
05 ELEMENT PIC 9(9) COMP OCCURS 100 TIMES.
The initial value of MAX-COUNT must be the same as the number of occurrences
of ELEMENT.
The maximum number of elements that cpinfo can contain is the initial value of
MAX-COUNT divided by 2.5. The cpinfo in the preceding example can contain
40 elements.
The required number of table elements depends on the number of operations the
list must record. The worst-case situation uses six elements.
A complete checkpoint list is required only when a program has a backup that must
be kept current. When a record of changes is not required, a null checkpoint list
can be used. This is an example description:
03 CP-LIST-1 PIC 9(9) COMP VALUE IS 0.
error-return
is a numeric data item that has one of these values upon completion:
Usage Consideration: In a fault-tolerant program, put the CHECKPOINT statement that
specifies cpinfo immediately before the call to COBOL_CONTROL_; otherwise, the
queued information can be lost if a backup process takes over.
Value Meaning
n The call to CONTROL caused Guardian file error n.
0* No error occurred.
1 A required parameter is missing.
2 file-name is not a COBOL file name.
5 One of:
•
file-name specifies an open file that is either $RECEIVE or is open for
Fast I-O.
•
file-name specifies a closed file and there is not enough control space
to allocate the queued information for the next open request.
*error-return is 0 for a deferred call (that is, one that is held until the file is open). If an error occurs at
that time, a run-time diagnostic is issued.