Passing Prototyped Parameters

are then built by the calling procedure and passed as hidden para called procedure. Operational descriptors will not be built for omitt

You can retrieve information from

an operational descriptor

using the

APIs Retrieve Operational Descriptor Information (CEEDOD) and Get Descr

Information

About a String Argument (CEESGI).

 

 

 

 

 

 

Note that

operational descriptors

are

only

allowed

for

bound

calls. Fu

non-prototyped calls, an error message will

be

issued

by

the

compiler

operation

code extender is specified

on

a

CALL

operation.

 

Figure 66 shows an example of the keyword OPDESC.

*-------------------------------------------------------------

*Len returns a 10-digit integer value. The parameter

*is a character string passed by read-only reference.

*Operational descriptors are required so that Len knows

*the length of the parameter.

*OPTIONS(*VARSIZE) is required so that the parameter can

*be less than 32767 bytes.

 

*-------------------------------------------------------------

 

D Len

 

 

PR

10I 0 OPDESC

D

 

 

 

 

 

32767A

OPTIONS(*VARSIZE) CONST

 

 

 

 

Figure

66.

Requesting Operational Descriptors for a Prototyped Procedure

For an

 

example

of

how to use operational descriptors see “Sample Serv

Program”

on

page 94.

The example

consists of a service program which

character

strings

which are passed to it to their hexadecimal equi

service

program uses

operational descriptors to determine the length

acter

string

and

the

length to

be converted.

Omitting Parameters

 

When

 

calling

a

procedure,

you may sometimes want

to

leave

out

a

par

 

may

 

be that it is not relevant

to the called procedure. For

exampl

 

might

 

arise

when

you

are

calling

the

ILE

bindable APIs.

 

Another reas

 

that

 

you

are calling an older procedure

that does

not

handle

this

 

eter.

If

 

you need to omit a parameter on a call, you have two c

¹

Specify

 

OPTIONS(*OMIT)

and

pass

*OMIT

 

 

 

 

 

 

 

 

¹

Specify

 

OPTIONS(*NOPASS) and do not pass the parameter.

 

 

 

 

 

The

 

primary

difference

between

the

two

methods

has

to

 

do with

how

see

 

if a parameter has been omitted. In either case, an omitted

be

referenced

by

the called

procedure; if it is, unpredictable

 

the

called

procedure is designed to handle different

numbers

of

pa

 

will

 

have to check for the number of

parameters

passed.

If

*OMIT

 

'count'

as

a

parameter.

 

 

 

 

 

 

 

 

 

 

 

Chapter 10. Calling Programs and Procedures139

Page 162 Page 164
Page 163
Image 163
IBM AS/400 Omitting Parameters, When Calling Procedure You may sometimes want Leave Out Par, Options*Omit, Count Parameter
Page 162 Page 164

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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