COBOL Manual for TNS and TNS/R Programs

Process Initiation, Communication, and
Management
HP COBOL Manual for TNS and TNS/R Programs—522555-006
31-16
RECEIVE-CONTROL Paragraph
RECEIVE-CONTROL Paragraph
The RECEIVE-CONTROL paragraph of the Environment Division is an HP extension
to COBOL. The RECEIVE-CONTROL paragraph in process $XX serves these
purposes:
•
It defines the receive-control table for process $XX. This specifies the maximum
number of other processes that can have process $XX open concurrently. When all
such other processes close process $XX, an HP COBOL run-time routine reports
an end of file (EOF) on $RECEIVE.
•
It defines the reply table for process $XX. This specifies the number of replies (and
the length of a reply) to be saved for each requesting process. A process with a
fault-tolerant requester must allow for replies to be saved so that the fault-tolerant
facility can retransmit them to restore synchronization in the case of a takeover by
the requester’s backup process. (If the requester is not fault-tolerant, the reply
table is useless and wastes space.)
•
It designates a data item to contain an error code to be returned to a requesting
process that is handling process $XX as a device. Every device in the system
returns an error code, a condition code, and a reply-message text.
•
It designates a data item to contain the message source descriptor. This fixed-
format item is defined in RECEIVE-CONTROL Paragraph. When the HP COBOL
run-time routines complete a successful READ on $RECEIVE, they update this
data item to report:
°
The message source (the operating environment or another user process)
°
The entry number in the receive-control table
°
The process ID of the requesting process (name, processor number, and
number of process in that processor)
•
It specifies which classes of operating environment messages are to be passed to
process $XX.
An ordinary Pathway server uses only three entries of the RECEIVE-CONTROL
paragraph:
•
TABLE OCCURS
Specifies how many requesters can have the server open at one time. Any
additional requesters attempting to open the server are refused. This value must
be greater than or equal to the MAXLINKS value in the PATHCOM command file
that created the PATHMON environment. A large value is recommended.
Note. If the process is running at a high PIN, the process ID that the operating
environment returns is synthetic. For information about synthetic IDs of high-PIN
processes, see the Guardian Application Conversion Guide.