RPG Programming in ILE

Alternatively,

you may create

a

program using

separate

commands

for

comp

and binding. This two-step process allows you

to

reuse

a

module

or

upd

module without

recompiling the

other

modules in

a

program.

In addition,

you can combine modules from

any

ILE

language,

you can

create

and

main

mixed-language

programs.

 

 

 

 

 

 

 

 

 

In the two-step process, you create a module object using the Creat (CRTRPGMOD) command. This command compiles the source statements into a module object. A module is a nonrunnable object; it must be bound into object to be run. To bind one or more modules together, use the Cre (CRTPGM) command.

Service programs are a means of packaging the procedures in one or mo modules into a separately bound object. Other ILE programs can access dures in the service program, although there is only one copy of the program on the system. The use of service programs facilitates modular maintainability. You can use off-the-shelf service programs developed by parties or, conversely, package your own service programs for third-par service program is created using the Create Service Program (CRTSRVPGM) command.

You can create a binding directory to

contain the names of modules a

programs that your program or

service

program

may

need.

A

list of

bind

ries can be specified when you create

a

program on

the

CRTBNDRPG,

CRTSRVPGM, and CRTPGM commands. They can also

be

specified

on

the

 

CRTRPGMOD command;

however,

the

search

for

a binding directory is done

the module is

bound at

CRTPGM

or CRTSRVPGM

time. A

binding

directory

can

reduce program size because modules or service programs listed in a directory are used only if they are needed.

Figure 5 shows the two approaches to program creation.

RPG IV source specifications

Externally described files

Copy source text

ILE HLL Modules,

RPG Module

Service Programs

(CRTRPGMOD)

ILE Program

(CRTBNDRPG)

ILE Program (CRTPGM)

One-Step Process

Two-Step Process

Figure 5. Program Creation in ILE

 

Once a program is created you can update the program using the Upd (UPDPGM) or Update Service Program (UPDSRVPGM) commands. This is useful, because it means you only need to have the new or changed module ob able to update the program.

For

more

information on the one-step process,

see Chapter 6,

“Creating a

with

the

CRTBNDRPG Command” on page 57. For more

information on

the two-

18 ILE RPG for AS/400 Programmer's Guide

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IBM AS/400 manual Language You can Create, CRTSRVPGM, and Crtpgm commands. They can also Specified
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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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