IBM AS/400 manual Accessing Display Devices, Using Sequential Files, Specifying a Sequential

Using Sequential Files

Accessing Display Devices

You use display files to exchange information between								your	program		and
device		such as a			workstation. A display file is		used	to	define	the
mation		that	is	to	be	presented on a display, and to		define how		the
be	processed			by	the	system on its way to and	from	the	display.
See	Chapter 18,			“Using		WORKSTN Files” on page 331	for a	discussion		on	ho
use	WORKSTN		files.

Using Sequential Files

Sequential	files in	an ILE	RPG	program associate with any sequentially o
file on	the AS/400	system,	such	as:

¹Database file

¹Diskette file

¹Printer file

¹Tape file.

The	file name	of the SEQ file in	the	file	description			specifications
AS/400	file. The file description of the AS/400					file	specifies		the	act
e.g. tape, printer and diskette.
You	can also use the CL override		commands,		for	example		OVRDBF,	OVRDKTF
and	OVRTAPF, to	specify the actual	I/O	device		when	the program is			ru

Specifying a Sequential	File
A	sequential		(SEQ)	device	specification, entered		in	positions	36	through
file description specification, indicates that the input or output is
sequentially-organized file. Refer						to Figure 162	on	page 327.	The		actua
be associated with the file while running the							program can be			specifi
override		command		or by	the file	description that		is pointed to by t
SEQ	is specified			in a program, no device-dependent				functions	such		as s
or	CHAIN	can	be	specified.

The following figure shows the operation codes allowed for a SEQ file.

Table	26.	Valid File Operation Codes for a Sequential File
File	Description	Specifications		Calculation		Specifications Positions
	Positions
	17		18			26-35
I			P/S	CLOSE,	FEOD
I			F	READ,	OPEN,	CLOSE, FEOD
O				WRITE, OPEN, CLOSE, FEOD

Note: No print control specifications are allowed for a sequential file.

326 ILE RPG for AS/400 Programmer's Guide