IBM AS/400 manual ¹ Output, On page 333 shows an example of the DDS for a display-devic

Using Externally Described WORKSTN Files

In	addition to the	field	descriptions (such as field names and attri
for	a display-device	file	are used to:

¹Format the placement of the record on the screen by specifying th

number and position-number entries for each field and constant.

¹Specify attention functions such as underlining and highlighting fields,

image, or a blinking cursor.

¹Specify validity checking for data entered at the display work sta checking functions include detecting fields where data is required, mandatory fill fields, detecting incorrect data types, detecting da range, checking data for a valid entry, and processing modules 10 o digit verification.

¹Control screen management functions, such as determining if fields are

erased, overlaid, or kept when new data is displayed.

¹Associate indicators 01 through 99 with command attention keys or comma

function keys. If a function			key	is	described		as	a command	functi
both	the	response indicator and		the	data	record (with any			modific
on the screen) are returned			to the program. If a					function	key	is
command	attention key (CA), the		response indicator				is	returned	to	the
but the data record remains			unmodified.			Therefore,		input-only	charac
are blank and input-only numeric			field		are	filled	with	zeros,	unless
have been		initialized otherwise.

¹Assign an edit code (EDTCDE) or edit word (EDTWRD) keyword to a fie

specify how the field’s values are to be displayed.

¹Specify subfiles.

A display-device-record format contains three types of fields:

¹Input fields. Input fields are passed from the device to the program

program

reads

a

record.

Input fields can be initialized with

a d

the

default

value

is

not

changed,

the default

value

is

passed

to

Input

fields

that

are not initialized are displayed as blanks

into

station

user

can

enter

data.

¹ Output

fields. Output

fields

are passed

from

the

program

to

the

devi

the

program

writes

a record to a display. Output fields can

be

program

or by

the

record

format

in

the

device

file.

¹Output/input (both). fieldsAn output/input field is an output field that ca changed. It becomes an input field if it is changed. Output/input

passed	from	the program when the program writes a		record	to	a di
passed	to	the program when the program reads a record from the d
Output/input		fields	are used when the user is to	change	or	update
is written		to the	display from the program.

If you specify the keyword INDARA in the DDS for a WORKSTN file, th program passes indicators to the WORKSTN file in a separate indicator not in the input/output buffer.

For	a detailed description of an externally-described display-device f
of	valid DDS keywords, DDSsee Reftherence.

Figure 165 on page 333 shows an example of the DDS for a display-devic

332 ILE RPG for AS/400 Programmer's Guide