Pathway/iTS TCP and Terminal Programming Guide

Processing Unsolicited Messages
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
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Sending Unsolicited Messages to SCREEN COBOL
Requesters
Sending Unsolicited Messages to SCREEN COBOL
Requesters
Guardian processes send unsolicited messages to SCREEN COBOL requesters by using
the appropriate TCP. An application that sends multiple unsolicited messages to a TCP
should open the TCP only once and close it at the end of processing.
Such messages consist of two parts:
•
A UMP header that gets interpreted by the receiving TCP
•
The body of the message that gets passed to the SCREEN COBOL requester
program
The length of the receiving buffer within the requester program is established by the
application designer. The maximum length of a message can be configured through
PATHCOM. The length is that of the body of the maximum message, exclusive of the
UMP header.
To send a message to a SCREEN COBOL requester program, the sending process must
build a message whose header contains the Pathway/iTS terminal name; this message is
then sent to the TCP controlling the terminal.
There are two methods for obtaining the information necessary to complete the header
of an unsolicited message to a SCREEN COBOL requester.
•
The Subsystem Programmatic Interface (SPI), a token-oriented programmatic
interface provided by Compaq, provides the means whereby Guardian processes
outside of a PATHMON environment can communicate with the PATHMON
process to obtain the information necessary to complete the UMP header of a
message intended for a known terminal.
Given the Pathway/iTS terminal name, the management programming interface gets
the TCP system name and the Guardian process name. The procedure for doing this
for the terminal TERM-X is as follows:
1. Issue an INFO TERM TERM-X request. The response from PATHMON
contains the TCP name, such as TCP-X.
2. Issue a STATUS TCP TCP-X request. The response contains both the system
name and the Guardian process name of TCP-X.
Detailed information about the management programming interface to the Pathway
subsystem is presented in the NonStop™ TS/MP Management Programming
Manual and the Compaq NonStop™ Pathway/iTS Management Programming
Manual.
•
Assuming the requester has access (direct or indirect) to the process that will be
sending the unsolicited messages, the requester can initially send its information—
its Pathway/iTS terminal name, its TCP system name, and its TCP process name—
from the special registers LOGICAL-TERMINAL-NAME, PW-TCP-SYSTEM-
NAME, and PW-TCP-PROCESS-NAME by using the SEND (to server) verb.