IBM AS/400 manual Considerations, Overriding and Redirecting File Input and Output, General

Overriding and Redirecting File Input and Output

Chapter 15. General	File	Considerations
This	chapter	provides information on the following aspects of file pro
AS/400	using RPG:

¹ overriding and redirecting file input and output

¹ file locking by an RPG program

¹ record locking by an RPG program

¹ sharing an open data path

¹ AS/400 spooling functions

¹using SRTSEQ/ALTSEQ in an RPG program versus a DDS file

Overriding and Redirecting File Input and Output

OS/400 commands can be used to description or to redirect a allows you to specify a file (at compilation time):

override a parameter in the specifie file at compilation time or run time. at run time to replace the file spe

Compile

Time

RPG program

File name = FILEY

Device = DISK

Execution

Time

FILEY

File type =

PHYSICAL

Override Command:

OVRDBF FILE (FILEY) TOFILE (FILEA)

FILEA
File type =	Diskette
DEVICE
Device type =
DISKETTE

Figure

136.

Overriding File Input and Output Example

In

the

preceding example,

the

CL

command

OVRDBF

(Override

With Datab

File) allows the program to

run

with an

entirely

different

device

fil

fied

at

compilation

time.

To

override

a file

at run

time,

you

must

make

sure that

record

nam

are the same. The RPG program uses the record-format name on the i operations, such as a READ operation where it specifies what record expected.

Not all file redirections or overrides are valid. At run time, checki specifications within the RPG program are valid for the file being OS/400 system allows some file redirections even if device specifics

 Copyright IBM Corp. 1994, 1999 273