OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

Planning Your Program
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
4-2
Planning for Multiple GPI Sessions
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Using the SCF START command, you start the APPL, GI CLASS, and GI GROUP
objects that you have defined.
For details on GPI configuration, refer to the following manuals:
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OSI/MHS Configuration and Management Manual
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OSI/MHS SCF Reference Manual
Planning for Multiple GPI Sessions
You need to consider whether your gateway program requires multiple GPI sessions. If
so, you need to decide how to implement multiple sessions. In addition, you need to
decide what OSI/MHS GATEWAY object (gateway) will be linked to each session.
For each client process (executing client program), the GPI allows up to 15 GPI
sessions. To accommodate multiple GPI sessions, a number of GIPs equal to the
number of sessions must be configured and started prior to GPI operation. Each GIP is
configured as part of a gateway interface (GI) group. Each is replicated from the GIP
program file supplied with the GPI product.
Each GPI session is allocated its own GIP when the session is established by a call to
GPI_OPEN_ . The connection between the client process and the GIP remains until a
call to GPI_CLOSE_ ends the session.
There are many ways to implement a GPI gateway. You can, for instance, design a
single-session client program that does both outbound and inbound processing.
Alternately, you can design a program with two or more sessions, each limited to either
outbound or inbound processing. Finally, you can implement a gateway using multiple
client programs that run concurrently.
Each GPI session is linked to one OSI/MHS GATEWAY object. If a client program has
multiple GPI sessions, each can be linked to the same or a different GATEWAY object.
Up to 16 GATEWAY objects can be configured for each instance of OSI/MHS;
however, only one of those 16 can be of type P1-EXIT. Refer to Figure 4-1.
When calling GPI_OPEN_ to establish a session, the client program must provide the
name of the GATEWAY object to which it will link. The client program must also
provide the password and the fully qualified name of the MHS manager process that
configured that GATEWAY object.
For additional information on configuring GI groups and GATEWAY objects, refer to
the OSI/MHS Configuration and Management Manual.
Note. SCF objects do not relate to the XAPIA objects used by the GPI procedural interface.
Note. For performance and simplicity, Compaq recommends that you limit a gateway object to
a single session, and that you limit the session to either outbound or inbound processing. To
implement both outbound and inbound processing, Compaq recommends that you develop a
separate client program for each.