Exception Handling Overview

¹

Optionally

recovering

from

 

the exception

by passing the exception inf

 

to a piece of code to

take

any

necessary

actions.

 

 

 

 

When a run-time error occurs, an

exception message is generated. An e

message

has

one

of

the following

types depending

on

the

error

which

*ESCAPE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Indicates

that

a severe error has been detected.

 

 

*STATUS

 

Describes

the

status

of

work

being done by a program.

*NOTIFY

 

Describes a condition requiring corrective action or reply from

 

 

 

program.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Function

Check

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Indicates

that

one

 

of

the

three previous exceptions

occurred

 

 

 

not

handled.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Exception

messages

are

associated

with

call

stack

entries.

Each

call st

in

turn

associated

with

a

list

of

exception

handlers

defined

 

for tha

Call

Stack”

on page 129

for further discussion of a call stack.)

Figure 108

on

page 219

shows

 

a

call

stack

where an OPM program calls an

ILEprogram

consisting

of

several modules and therefore several procedure

to

this

figure

in

the

discussions

which

follow.

 

 

 

 

 

 

In general, when an exception occurs,

the handlers associated with the

entry

are

given

a

chance

to

handle

the

exception.

If

the

exception

any

of

the

handlers

on

the

list

then

it

is

considered

to

be

unhandle

the

following

default

actions

are

taken

for

the

unhandled

exception:

1.If the exception is a function check, the call stack entry is re stack.

2. The exception is moved (percolated) to the previous call stack entr

3. The exception handling process is restarted for this call stack ent

The action of allowing the previous call stack entry to handle

an

exc

referred

percolationto as

. Percolation continues until the exception is

handled

until

the

control

boundary is controlreachedboundary. A

is a call stack entry

for

which

the

immediately

preceding

call stack

entry is in

a or different

ac

is an

OPM

program.

In

Figure 108

on page 219

Procedure

P1 is the

contro

boundary.

218 ILE RPG for AS/400 Programmer's Guide

Page 241 Page 243
Page 242
Image 242
IBM AS/400 manual Indicates That Severe error has been detected, Describes Status Work Being done by a program, Call st
Page 241 Page 243

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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