How to "diskw" with stem variable - VM/CMS...

[tomsweb]

Fellow Programmers:

I have written a rexx exec to scan records in a dataset in vm/cms mainframe, and write certain records to an output file.

I am unable to succesfully write records to an output flat file (RECFM=F, LRECL=80). The problem is the output file contains the value "SLINE.1" on every line.

Can anyone help me straighten out the confusion over the "stem line.i" stuff? I think that is causing this mess.

Thanks!
TomsWeb

Here is the code...

SIGNAL ON ERROR
'EXECIO * DISKR TESTF FILE A (FINIS STEM IN.'
IF RC=2 THEN LEAVE
J = 0

LOOPA:
DO I = 1 TO IN.0
LINE = IN.I
PARSE VAR LINE V1 V2 .
LX=LINE.I
/* LZ = SUBSTR(LX,6,2)
SAY "LINE"LZ V2 . */
IF V2 = "CAR"
THEN OUT.J = V2
SAY OUT.J J
SIGNAL WRITEX
END
EXIT

WRITEX:
OUT=LABEL.J
'EXECIO 1 DISKW TOMMY FILE A 0 F 72 (FINIS STEM OUT.'
J = J + 1
I = I + 1
SIGNAL LOOPA
EXIT

RETURN 0

 

[KiwiREXXDude]

Probably the first thing I would suggest from looking at this is that you don't use EXECIO to write line-by-line. This will at least quadruple the execution time because of the excessive I/O. I recommend you create the whole stem and do 1 write.

Anyway, from reading this you want to read in file TESTF, and write it to file TOMMY if the second word is 'CAR'. As such there are a number of bugs in here (apart from the 'SIGNAL ON' to no-where, and the 'LEAVE' which should be 'EXIT');

* you do your SIGNAL to the WRITEX regardless of the IF - I think you want a 'THEN DO ... END'
* you set J to 0 then OUT.J so for the first record your OUT.0 will be a record not a number (stem.0 is supposed to be a record count like IN.0)
* you signal LOOPA from WRITEX which should put you into a permanant loop as you restart the DO I=1 every time you write a record
* you increment I in your WRITEX which means you skip the following input record when you do a write (which you may want to do)

Here's a suggestion;
SIGNAL ON ERROR
'EXECIO * DISKR TESTF FILE A (FINIS STEM IN.'
IF RC > 0 THEN do
say 'Read of file failed with return code 'rc
return rc
end
J = 0

DO I = 1 TO IN.0
LINE = IN.I
PARSE VAR LINE V1 V2 .
/* LX=LINE.I
LZ = SUBSTR(LX,6,2)
SAY "LINE"LZ V2 . */
IF V2 = "CAR" then do
call WRITEX
SAY OUT.J J
end
END
'EXECIO * DISKW TOMMY FILE A 0 F 72 (FINIS STEM OUT.'
Return 0

WRITEX:
J = J + 1
OUT.J = V2
Return

Error:
say 'Error on line 'sourceline()';'
say sourceline(sourceline())
Exit 8

 

[tomsweb]

This script seems to have errors. Control should go from loopa: to writex: as soon as it finds a match on:
'IF v2 = "CAR"'.

There it should write out the line that the match was found in.

As it is coded now, it will write a record to 'execio diskw'
regardless of a match.

What is the point of that, if I want to capture all records that contain the keyword "car"?

The issue is why I cannot write the matching records to
an ouput file using stem in 'EXECIO DISKW'?

Thanks,
Tom

 

[kevinf2349]

KiwiRexx's code doesn't look like it will write the line regardless to me.

The STEM variable looks like it is only getting incremented on a match to me. Have you inadvertently omitted the DO from the IF THEN for the match criteria.

One of the things I was always taught to avoid was the use of SIGNAL. In your script it looks like you increment I and then loop back to the DO I = 1 TO IN.0...thereby resetting I to 1 every time. I am surprised this isn't looping like crazy.

HTH

 

[KiwiREXXDude]

Tom, the point I was trying to make is it is in-efficient to do an EXECIO everytime you write a single record. The EXECIO in my sample is outside the LOOPA: in order to do one bulk write rather than a write each time.

I too was told not to use SIGNAL, hence my use of CALL (to WRITEX.

Maybe if I coloured the guts of the code around the IF's it would be easier for you to read;

J = 0
DO I = 1 TO IN.0
LINE = IN.I
PARSE VAR LINE V1 V2 .
IF V2 = "CAR" then do
call WRITEX
SAY OUT.J J
end
END
'EXECIO * DISKW TOMMY FILE A 0 F 72 (FINIS STEM OUT.'
Return 0