IBM AS/400 manual RPG IV Specifications, RPG IV Overview, section

RPG IV Overview

Chapter 1. Overview	of	the	RPG	IV	Programming	Language
This chapter		presents		a	high-level	review	of	the features of the R
ming language that distinguish RPG from other								programming	languages. You
should	be familiar		and	comfortable		with	all	of these	features befor

the RPG IV language. The features discussed here encompass the fo subjects:

¹Coding specifications

¹ The program cycle

¹Indicators

¹Operation codes

For more information on RPG IV,ILEseeRPG thefor AS/400 Reference.

RPG IV Specifications

RPG code is written on a variety of specification forms, each with functions. Many of the entries which make up a specification type a dependent. Each entry must start in a specific position depending on entry and the type of specification.

There are seven types of RPG IV specifications. Each specification Specifications must be entered into your source program in the order

Main source	section:
1.Control	specifications		provide	the	compiler	with information	about	gener
and running programs, such as the program name, date format,								and us
alternate		collating	sequence	or	file translation.
2.File description		specifications	describe all			the files that	your	program

3.Definition specifications describe the data used by the program.

4.Input

specifications

describe

the

input

records and

fields

used by

program.

5. Calculation

specifications

describe the calculations done on the data

order

of

the

calculations.

Calculation specifications

also

control

ce

and

output operations.

6. Output

specifications

describe

the

output

records

and

fields

used

b

program.

Subprocedure

section:

1.Procedure

specifications

mark the beginning and end of the subprocedur

indicate

the subprocedure

name, and

whether

it

is

exported.

2.Definition

specifications

describe the local data used by the subpro

3.Calculation

specifications

describe

the

calculations

done

on

both

the

and

local

data

and the order

of the

calculations.

 Copyright IBM Corp. 1994, 1999 3