A lot of programmers standardize on indicator usage for function keys
within display file programs, e.g. *IN01 for F1, *IN03 for F3, etc,
which is fine and readable if you are aware of the convention being
used.
However, if you want to cut down on the number of indicators used in your program and make it easier to read and maintain then you should
code your display files not to use response indicators and make use of
the device dependent I/O feedback area of the File Information Data
Structure instead.
Position 369 of the File Information Data Structure for display files
contains a hex byte that represents the function key (or other grey
key) pressed by the user.
By coding field @FNKEY in this position of the INFDS and then defining
text constants for the appropriate function key value, I can test for
the use of function keys within my programs by using:
@FNKEY IFEQ $F5
...
...
ENDIF
as opposed to:
*IN05 IFEQ *ON
...
...
ENDIF
The source snippets below show the coding needed within your RPG/400
program to use this technique.
Code
RPG SOURCE SNIPPET
==================
FWORKSTN CF E WORKSTN KINFDS INFDS
F* Display File
F*----------------------------------------------------------------
IINFDS DS
I 369 369 @FNKEY
I* Function key values
I X'31' C $F1
I X'32' C $F2
I X'33' C $F3
I X'34' C $F4
I X'35' C $F5
I X'36' C $F6
I X'37' C $F7
I X'38' C $F8
I X'39' C $F9
I X'3A' C $F10
I X'3B' C $F11
I X'3C' C $F12
I X'B1' C $F13
I X'B2' C $F14
I X'B3' C $F15
I X'B4' C $F16
I X'B5' C $F17
I X'B6' C $F18
I X'B7' C $F19
I X'B8' C $F20
I X'B9' C $F21
I X'BA' C $F22
I X'BB' C $F23
I X'BC' C $F24
I X'BD' C $CLEAR
I X'F1' C $ENTER
I X'F3' C $HELP
I X'F4' C $RLLDN
I X'F5' C $RLLUP
I X'F4' C $PAGUP
I X'F5' C $PAGDN
I X'F6' C $PRINT
I X'F8' C $BCKSP
I X'3F' C $AUTO
I*----------------------------------------------------------------
C ...
C ...
C EXFMTxxxxxxxx
C*
C* Process function keys...
C*
C SELEC
C @FNKEY WHEQ $F1
C EXSR HELP
C @FNKEY WHEQ $F3
C ..
C ...
C @FNKEY WHEQ $ENTER
C ...
C ENDSL
C*----------------------------------------------------------------
DDS SOURCE SNIPPET
==================
A R DSPFMAT
A CF01
A CF03
A PAGEDOWN
A etc...
==================================
MORE INFORMATION ON THIS TOPIC
==================================
The Best Web Links: tips, tutorials and more.
Ask your programming questions--or help out your peers by answering them--in our live discussion forums.
Ask the Experts yourself: Our application development gurus are waiting to answer your programming questions.
