OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide

Introduction
OSI/MHS Gateway Programmatic Interface (GPI) Programming Guide—424822-001
1-2
Compaq GPI
Briefly, the template has two key features:
•
An information architecture based on object-oriented structures (objects)
•
A set of services to manage and transfer objects
Objects are structures that contain the X.400 information. A root object is a special
structure that contains an entire X.400 message, probe, report, or P1-encoded object.
The API supplies procedures that manipulate the objects in a well-defined manner.
Objects can be built (composed), taken apart (decomposed), inspected, and copied.
Root objects can also be transferred in or out. Using objects, the GPI program can
translate information between a proprietary format and a functionally equivalent X.400
format.
In the XAPIA specifications, software that implements functions of the API is called the
service. Software that uses this service is called the client (Figure 1-2
). In this guide,
the client is also called the client program.
Compaq GPI
The GPI is Compaq’s implementation of XAPIA X.400 API specifications. The GPI
provides direct programmatic access to OSI/MHS. It is installed on the same Compaq
NonStop system as the OSI/MHS subsystem to which it connects. You can use the GPI
to develop X.400 gateways for a wide range of proprietary electronic data interchange,
mail, and backbone messaging systems.
The GPI includes:
•
An information architecture based on XAPIA specifications
•
A set of procedures for object management and transfer based on XAPIA
specifications
•
Additional proprietary procedures for error reporting and gateway control
The advantages of the GPI are:
•
A well-known interface, familiar to X.400 programmers
Figure 1-2. Client and Service
102CDT .CDD
X.400 Gateway
MTA
API
Client Service
Proprietary
Message
System