Pathway/iTS TCP and Terminal Programming Guide

Processing Unsolicited Messages
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
7-15
Unsolicited-Message Layout, Reply Layout, and
Error Codes
For requesters that are started by a PATHCOM RUN PROGRAM command, only the
second method is appropriate because the logical name of the terminal is determined
dynamically by the PATHMON process.
The reply returned to the sender of an unsolicited message includes error information
when either of the following is true:
•
The supplied terminal name is not currently active. (The terminal is either stopped
or suspended.)
•
The unsolicited-message queue of the target requester is full.
Unsolicited-Message Layout, Reply Layout, and
Error Codes
The subsections that follow describe the format of unsolicited messages as sent by an
external process (outside the PATHMON environment) to the TCP, the format of replies
sent by the TCP to the external process, and the various reply codes that the TCP can
include in the reply record.
Unsolicited-Message Layout
Figure 7-1 illustrates, in a COBOL-like representation, the format of an unsolicited
message as viewed by both the TCP that receives it and the external process (outside the
PATHMON environment) that sends it.
Upon receipt of a message, the TCP strips off the header and stores only the text portion
in the target requester's queue.
Figure 7-1. UMP Message Format
01 UMP-MSG.
02 TCP-UMP-HDR.
03 PROTOCOL-ID PIC 9(4) COMP VALUE 42.
03 MSG-ID PIC 9(4) COMP VALUE 1.
03 MSG-VERSION PIC 9(4) COMP VALUE 1.
03 MSG-HEADER-LEN PIC 9(4) COMP VALUE 40.
03 DEST-NODE PIC X(8).
03 DEST-TCP-PROC PIC X(6).
03 LOGICAL-TERM-NAM PIC X(15).
03 FILLER PIC X.
03 MSG-SEQUENCE-NUM PIC 9(4) COMP.
02 SCOBOL-MSG.
03 MSG-TEXT PIC X(number-of-characters).