IBM AS/400 manual Associating Files with Input/Output Devices

Models: AS/400

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Device

Associating Files with Input/Output Devices

SPECIAL. Figure 126 on page 262 shows a file description specification f display (WORKSTN) file FILEX.

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FFilename++IPEASFRlen+LKlen+AIDevice+.Keywords+++++++++++++++++++++++++++++

FFILEX

CF

E

 

 

 

WORKSTN

 

 

 

 

 

 

 

 

Figure 126. Identifying a Display File in an RPG Program

 

Note

that

it is

the

file name, not the device name

(specified

in po

 

42)

which points to the OS/400

file

description that

contains

the

speci

 

the

actual

device.

 

 

 

 

 

 

 

 

The

RPG device

types

correspond to the above file

types

as follows:

 

 

 

 

 

 

 

 

Table

16. Correlation of RPG Device Types with AS/400 File Types

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RPG Device

Type

 

 

AS/400 File

Type

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DISK

 

 

 

database, save,

DDM files

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PRINTER

 

 

 

printer

files

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WORKSTN

 

 

 

display,

ICF files

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SEQ

 

 

 

tape, diskette,

save,

printer, database

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SPECIAL

 

 

 

N/A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 127 illustrates the association of the RPG file name FILEX, as c Figure 126, with a system file description for a display file.

RPG program

File name = FILEX Device = WORKSTN

FILEX

Device type =

DISPLAY

Figure

127. Associating a file name with a display file description

 

 

 

 

At

compilation

time,

certain

RPG

operations

are valid only for a

specifi

device

name.

In

this

respect,

the

RPG

operation

is

device

dependent.

of

device dependency

is that

the

EXFMT

operation

code is

valid

only

f

WORKSTN

device.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other

operation codes are device independent, meaning that they

can

b

any

device

type.

For

example,

WRITE

is

a

device-independent

operation.

The

SEQ

Device

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The

device SEQ is an independent device type. Figure 128 on page 263

 

the

association

of

the RPG

file name FILEY

with

a

system

file

descri

sequential device. When the program is run, the actual I/O device is description of FILEY. For example, the device might be PRINTER.

262 ILE RPG for AS/400 Programmer's Guide

Page 286
Image 286
IBM AS/400 manual Associating Files with Input/Output Devices