Program/Procedure Call Overview

Chapter 10. Calling Programs and Procedures

In ILE, it is possible to call either a program or procedure. Furt provides the ability to call prototyped or non-prototyped programs and (A prototype is an external definition of the call interface that a check the interface at compile time.)

The

recommended

way

to call

a program or procedure is to

use a pr

The

syntax

for

calling and passing parameters to prototyped

procedure

grams uses the same free-form syntax that

is

used

with built-in func

expressions.

For

this

reason,

a prototyped

call

is

sometimes

referred

form'

call.

 

 

 

 

 

 

 

 

Use the CALL or CALLB operations to call a program or procedure when:

¹ You have an extremely simple call interface

¹ You require the power of the PARM operation with factor 1 and

¹ You want more flexibility than is allowed by prototyped parameter

This chapter describes how to:

¹ Call a program or procedure

¹ Use a prototyped call

¹Pass prototyped parameters

¹ Use a fixed-form call

¹ Return from a program or procedure

¹ Use ILE bindable APIs

¹ Call a Graphics routine

¹Call special routines

Program/Procedure Call Overview

Program

processing

within ILE occurs

at the

procedure

level.

ILE

prog

of

one

or

more modules which in turn consist

of

one

or

more

procedu

RPG

module

contains

an optional main

procedure

and

zero

or more

subpro

dures. In this chapter, the term 'procedure' applies to both main subprocedures.

An

ILE

'program

call' is

a

special form of procedure call;

that is,

program entry procedure. A program entry procedure is

the

procedure

nated

at program creation

time to receive control when

a

program

is

entry

module of the program is an ILE

RPG

module, then

the main

proc

that

module is

called

by

the program

entry

procedure

immediately

af

is

called.

 

 

 

 

 

 

 

 

This section contains general information on:

¹ Program call compared to procedure call

¹ Call stack (or how a series of calls interact)

Copyright IBM Corp. 1994, 1999

127

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IBM AS/400 manual Calling Programs and Procedures, Program/Procedure Call Overview, 127
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AS/400 specifications

The IBM AS/400, now known as the IBM iSeries, is a midrange computer system that has been a cornerstone of enterprise computing since its introduction in 1988. Designed to provide a robust platform for business applications, the AS/400 is celebrated for its reliability, scalability, and integrated database capabilities.

One of the key features of the AS/400 is its Integrated Operating Environment, which blends hardware and software resources seamlessly. This integration allows businesses to execute diverse workloads, ranging from traditional applications to modern web-based services, all on a single platform. The operating system, OS/400 (now IBM i), offers a rich set of APIs and tools for developers, simplifying application development and management.

Another standout characteristic of the AS/400 is its built-in database, DB2 for i. This powerful relational database management system allows for efficient data handling and provides advanced features such as support for SQL, XML, and JSON, making it easier for businesses to manage their data and integrate it with other systems. The database's tight integration with the operating system enables high performance and security.

In terms of scalability, the AS/400 can accommodate small businesses as well as large enterprises, with the ability to support hundreds of users simultaneously. Its architecture allows for easy upgrades in hardware, meaning that organizations can scale their systems without replacing the entire infrastructure.

Security is another critical attribute of the AS/400. With a sophisticated security model, it offers built-in user authentication, access control, encryption, and auditing capabilities to protect data and applications from unauthorized access.

The AS/400 also supports multiple programming languages, including RPG, COBOL, Java, and PHP, giving organizations the flexibility to choose the development tools that best fit their needs. This diversity helps maintain legacy applications while also developing new ones that leverage modern technologies.

Moreover, the platform supports both traditional green-screen interfaces and modern graphical user interfaces, allowing organizations to transition smoothly into contemporary user experience paradigms.

Overall, the IBM AS/400 stands out as a resilient, flexible, and secure computing platform that enables organizations to effectively manage their business operations, streamline processes, and adapt to changing market demands. Its unique combination of integrated features and capabilities ensures that it remains relevant in today's fast-paced technology landscape.
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