as400 interview questions and answers-Part 18
1. What is EXTNAME keyword in RPGLE? Explain with example EXTNAME keyword.
Ans:
o
EXTNAME(file-name{:format-name}{:*ALL|
*INPUT|*OUTPUT|*KEY})
The EXTNAME keyword is used to specify the name of the
file which contains the field descriptions used as the subfield description for
the data structure being defined.
The file-name parameter is required. Optionally a format
name may be specified to direct the compiler to a specific format within a
file.
The last parameter specifies which fields in the external
record to extract:
·
*ALL extracts all
fields.
·
*INPUT extracts
just input capable fields.
·
*OUTPUT extracts
just output capable fields.
·
*KEY extracts just
key fields.
D Fileds1 E DS Export
D EXTNAME(file1)
Structure of the externally described data
structure:
·
Subfield name : Same
as the external file’s fields name, unless it id renamed by keyword EXTFLD
or the PREFIX
keyword on a definition specification is used to apply a prefix).
·
Subfield length
·
Subfield internal data type
All data structure keywords
except LIKEDS and LIKEREC are allowed with the EXTNAME keyword.
D D0220NEW E DS PREFIX(D21:3)
D EXTNAME(CZGD02H0:CZTD02H2)
D D0220OLD E DS PREFIX(D@@:3)
D EXTNAME(CZGD02H0:CZTD02H2)
2. Explain CALL opcode in rpgle.
Ans:
CALL(E) (Call a Program)
·
This op-code passes control to the program
specified in factor 2. It’s a dynamic call operation.
·
Program name should be in quotes.
·
If there is any error in this call operation
then the error can be traced with operator extender ‘E’ and LO level indicator
which turns on in case of any error.
·
If we don’t want to use error indicator with
operator extender ‘E’ even then we can trace the error by using the built-in
function %ERROR and %STATUS. For more information see chapter
File and Program exception.
·
If the called program returns with LR indicator
on, the calling program can trace that will EQ indicator.
>
|
Factor 1
|
Op-code
|
Factor 2
|
Result Field
|
Resulting Indicators
HI LO EQ
|
|
|
CALL(E)
|
‘program name’
|
[parameter list]
|
|
[error]
|
[LR}
|
Example
Columns . . . : 6 80 Browse AMINEM/QRPGLESRC
SEU==> OP_CALL
FMT C CL0N01Factor1+++++++Opcode&ExtFactor2+++++++Result++++++++Len++D+HiLoEq....
*************** Beginning of data ****************************************************
0001.00 C PLST1 PLIST 130125
0002.00 C PARM a 2 0 130125
0003.00 C PARM b 2 0 130125
0004.00 C PARM c 2 0 130125
0005.00 * 130125
0006.00 C Z-ADD 11 a 130125
0007.00 C Z-ADD 22 b 130125
0008.00 C Z-ADD *zeros c 130125
0009.00 C CALL 'OP_CALL1' PLST1 130125
0010.00 C c DSPLY 130125
0011.00 C SETON LR 130125
****************** End of data *******************************************************
Columns . . . : 6 80 Browse AMINEM/QRPGLESRC
SEU==> OP_CALL1
FMT C CL0N01Factor1+++++++Opcode&ExtFactor2+++++++Result++++++++Len++D+HiLoEq....
*************** Beginning of data ****************************************************
0001.00 C *ENTRY PLIST 130125
0002.00 C PARM p 2 0 130125
0003.00 C PARM q 2 0 130125
0004.00 C PARM r 2 0 130125
0005.00 C EVAL r=p+q 130125
0006.00 C RETURN 130125
****************** End of data *******************************************************
Output