OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

Introduction
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
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GIP
The GPI library includes:
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Procedures that are used to:
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Manage objects
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Transfer root objects in or out
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Report errors
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Control the gateway
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Declaration files for the procedures
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Parameters to procedure calls
GIP
The GIP connects the gateway to processes within the OSI/MHS subsystem. At run
time, this process provides access to input and output message queues associated with
the OSI/MHS MTA to which the GPI connects.
GIPs are statically configured for an OSI/MHS subsystem in the same manner as
OSI/MHS processes such as MRPs. GIPs are configured as part of a gateway interface
(GI) group. Each GIP supports one GPI session; enough GIPs must be configured and
started to accommodate the number of concurrent GPI sessions desired.
Each gateway session is identified by a unique session identifier. Session identifiers are
allocated by the GPI service (returned by the GPI_OPEN_ procedure). Because each
client program can have up to 15 sessions, there might be up to 15 GIPs used by each
client process (executing client program).
A client program and its GIPs run on the same system as the OSI/MHS subsystem to
which the gateway is attached.
MHS Manager Process
The MHS manager process is the focal point for configuration and control of the
OSI/MHS subsystem. Among other functions, it maintains the OSI/MHS configuration
database and starts and monitors subsystem processes. Throughout operation of a GPI
session, the MHS manager process exchanges control information with the GIP
allocated to that session.
The MHS manager process is aware of active GIPs, because they are added to an
OSI/MHS configuration in the same way as other OSI/MHS groups. GI groups are
under the control of the MHS manager. A static number of these groups is added and
started by an administrator using Subsystem Control Facility (SCF) commands to
OSI/MHS. For additional information about adding GI groups, refer to the OSI/MHS
Configuration and Management Manual.
MR Group
The Message Relay Group (MR Group) is composed of the Message Relay Process
(MRP), The Reliable Transport Service (RTS), and a PDU store. An MR group is a