Multiple Procedures Module

Subprocedures

offer

another

feature. You

can

pass parameters

to a

s

by value, and you can call

a subprocedure

in

an

expression

to

return

Figure 12 on

page 34

shows

what a module might

look

like with

multiple

p

dures.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*MODULE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Main Procedure

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H specifications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F specifications

 

Main

 

 

 

 

D specifications - Data items visible

 

Source

 

 

 

 

 

 

 

throughout module

 

Section

 

 

 

 

I specifications

 

 

 

 

 

 

 

 

C specifications

 

 

 

 

 

 

 

 

O specifications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Subprocedure 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P specification

 

 

 

 

 

 

 

 

D specifications - Data items visible only

 

 

 

 

 

 

 

 

 

 

 

to Subprocedure 1

 

 

 

 

 

 

 

 

C specifications - Can access local and

 

 

 

 

 

 

 

 

 

 

 

global data items

 

 

 

 

 

 

 

 

P specifications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Subprocedure 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P specification

 

 

 

 

 

 

 

D specifications - Data items visible

 

 

 

 

 

 

 

 

 

 

only to Subprocedure 2

 

 

 

 

 

 

 

C specifications - Can access local and

 

 

 

 

 

 

 

 

 

 

global data items

 

 

 

 

 

 

 

P specifications

 

 

 

 

 

 

 

 

 

 

 

 

 

Program Data - part of main source section

Figure 12. An ILE RPG module with Multiple Procedures

Local Scope

Local Scope

Global Scope

As the picture suggests, you can now

code

subprocedures

to

handle

pa

tasks.

These

tasks may be needed by

the

main procedures

or by

othe

the application. Furthermore, you can declare temporary data

items

in

dures

and not

have to worry if you

have

declared them

elsewhere

in

Prototyped Calls

To call a subprocedure, you must use a prototyped call. You can also program or procedure that is written in any languageprototypedin callthis way. A is one where the call interface is checked at compile time through t

prototype.prototypeA is a definition of the call interface. It includes information:

¹ Whether the call is bound (procedure) or dynamic (program)

¹ How to find the program or procedure (the external name)

34 ILE RPG for AS/400 Programmer's Guide

Page 58
Image 58
IBM AS/400 manual Prototyped Calls, What a module might, Like with Multiple Dures, Module

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.