IBM AS/400 manual Multiple-Device Files

Multiple-Device Files

operations. See the sections on inviting a programICF Programmdevingce in manual and Data Management manual.

¹The READ operation either processes a read-from-invited-program-devic operation or a read-from-one-program-device operation. When no NEXT op tion is in effect, a program-cycle-read or READ-by-file-name operati input from any of the devices that have been invited to respond invited-program-device). Other input and output operations, including a READ-by-file-name after a NEXT operation, and a READ-by-format-name, process a read-from-one-program-device operation using the program de indicated in a special field. (The field is named in the DEVID description specification lines.)

This device may be the device used on the last input operation, specify, or the requesting program device. See the sections on r invited program devices and on reading from one programICF Pro- device in gramming manual andData Management manual.

¹The NEXT operation specifies which device is to be used in the

READ-by-file-name operation or program-cycle-read operation.

¹ The	POST	operation	puts information	in the INFDS information data stru
The	information may be about a			specific	device or about the fi
operation		is not	restricted to	use with	multiple-device files.)

See theILE RPG for AS/400 Referencefor details of the RPG operation code

On the file description specification you can specify several keywo processing of multiple-device files.

¹The MAXDEV keyword indicates whether it is a single or multiple de

Specify MAXDEV(*FILE) to process a multiple device file with the ma number of devices taken from the definition of the file being pr Specify MAXDEV(*ONLY) to process only one device.

¹ The DEVID keyword allows you to

specify

the

name

of

a

program

d

which input and output operations

are

directed.

When a read-from-one-program-device

or

WRITE

operation

is

issued,

t

device used for the operation

is the device specified as the

DEVID

keyword. This field

is

initialized

to

blanks

and

is updated

of the device from which

the

last

successful input

operation occ

also

be set explicitly by

moving

a value

to

it.

The

ACQ

operation

affect the value of this field. If the DEVID keyword is not operation is performed against the device from which the last su

operation occurred. A blank device name				is	used if	a read oper
yet	been performed successfully	from	a	device.
When	a read-from-one-program device	or	WRITE		operation	is issued w

blank device name, the RPG compiler implicitly uses the device name requestor device for the program. If you call an RPG program int acquire an ICF device against which you want to perform one of ations, you must explicitly move the device name of the ICF devic field name specified with the DEVID keyword prior to performing If this is not done, the device name used will either be blank

interactive requestor device	name is used), or the device name u
from the last successful input	operation. Once you have performed

Chapter 18. Using WORKSTN Files343