Program/Procedure Call Overview

Sometimes you may not be sure of the exact format of the data t passed to you. In this case you may request that operational de passed to provide additional information regarding the format of the parameters.

¹Number of parameters

In general, you should pass the same number of parameters as expe the called program or procedure. If you pass fewer parameters t expected, and the callee references a parameter for which no da passed, then the callee will get an error.

¹Passing less data

If you pass a parameter

and

you

pass too little

data,

your

appli

work

correctly.

If

changing

the

parameter,

you

may

overwrite

storag

the

parameter,

you

may

misinterpret

the

parameter.

By

prototyping

t

eter, the

compiler

will check

to

see that

the

length

is

appropriat

eter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If

the

callee

has

indicated

(through

documentation

or

through

that

that a parameter can be shorter than

the

maximum length,

you

can

s

shorter

parameters.

(Note, however, that the called

procedure

must

in a

way

to handle

less

data

than

required.)

 

 

 

 

 

 

¹Order of evaluation

There

is no guaranteed order for evaluation

of parameters on a pro

This

fact

may

be important, if a parameter

occurs

more than once

eter

list,

and

there is the possibility of

side

effects.

¹Interlanguage call considerations

Different HLLs support different ways of representing data as well ways of sending and receiving data between programs and procedures general, you should only pass data which has a data type common to calling and called program or procedure, using a method supported by

Table 10 on page 133 associates the above considerations with the two parameters: prototyped or non-prototyped.

132 ILE RPG for AS/400 Programmer's Guide

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IBM AS/400 manual Program/Procedure Call Overview
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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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