Example of Using a Special File
Figure 1 shows how to use the RPG device name SPECIAL in a program. In this example, a file description found in the file EXCPTN is associated with the device SPECIAL.
Figure 1. SPECIAL Device
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
FFilename++IPEASFRlen+LKlen+AIDevice+.Keywords+++++++++++++++++++++++++++++
FEXCPTN O F 20 SPECIAL PGMNAME('USERIO')
F PLIST(SPCL)
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
DName+++++++++++ETDsFrom+++To/L+++IDc.Functions++++++++++++++++++++++++++++
D OUTBUF DS
D FLD 1 20
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
CL0N01Factor1+++++++Opcode(E)+Factor2+++++++Result++++++++Len++D+HiLoEq....
C SPCL PLIST
C PARM FLD1
C MOVEL 'HELLO' FLD
C MOVE '1' FLD1 1
C WRITE EXCPTN OUTBUF
C MOVE '2' FLD1 1
C WRITE EXCPTN OUTBUF
C SETON LR
Figure 2 shows the user-written program USERIO.
Figure 2. User-written program USERIO
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
DName+++++++++++ETDsFrom+++To/L+++IDc.Functions++++++++++++++++++++++++++++
D ERROR S 5S 0
*.. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 ...+... *
CL0N01Factor1+++++++Opcode(E)+Factor2+++++++Result++++++++Len++D+HiLoEq....
*----------------------------------------------------------------*
* The first 4 parameters are ILE RPG created parameter list. *
* The rest are defined by the programmer-defined PLIST. *
*----------------------------------------------------------------*
C *ENTRY PLIST
C PARM OPTION 1
C PARM STATUS 1
C PARM ERROR 5 0
C PARM AREA 20
C PARM FLD1 1
*----------------------------------------------------------------*
* The user written program will perform the file I/O according *
* to the option passed. *
*----------------------------------------------------------------*
C SELECT
C WHEN OPTION = 'O'
C* perform OPEN operation
C WHEN OPTION = 'W'
C* perform WRITE operation
C WHEN OPTION = 'C'
C* perform CLOSE operation
C ENDSL
C RETURN
The I/O operations for the SPECIAL device are controlled by the user-written program USERIO. The parameters specified for the programmer-defined PLIST(SPCL) are added to the end of the RPG-created parameter list for the SPECIAL device. The programmer-specified parameters can be accessed by the user ILE RPG program and the user-written routine USERIO; whereas the RPG-created parameter list can be accessed only by internal ILE RPG logic and the user-written routine.