RE: Loop code

["M. Lazarus" <mlazarus@xxxxxxxx>]

John,

 The %EOF and %Found flags are relatively new, nowhere near 20 years 
old.  I used the same technique as you in the "olden" days, when you could 
use the same resulting indicator for both opcodes.  I suggest you inspect 
your code to see that it's really doing what you intend it to do.

 -mark

At 3/26/04 02:36 PM, you wrote:
> Mark,
> Thanks for the advice, but I'll stick with what has worked for the past 20
> years or so.
>
> John
>
> -----Original Message-----
> From: M. Lazarus [mailto:mlazarus@xxxxxxxx]
> Sent: Friday, March 26, 2004 12:38 PM
> To: RPG programming on the AS400 / iSeries
> Subject: RE: Loop code
>
>
> John,
>
>   Not so fast!!  You have two separate conditions.  The priming CHAIN
> generates one condition and the READx another.  So you need to account for
> that.  Putting both conditions on the loop is kludgy, IMHO.  Both
> conditions will be tested during each loop execution.  Unfortunately, IBM
> chose this implementation, so the easiest is the use SETLL/READE, so the
> I/O opcodes are compatible.
>
>   -mark
>
> At 3/26/04 01:12 PM, you wrote:
> >I stand corrected, if you change the %eof to %found.
> >Boy, these BIF's are wonderful, aren't they.
> >
> >John Brandt
> >
> >
> >-----Original Message-----
> >From: M. Lazarus [mailto:mlazarus@xxxxxxxx]
> >Sent: Friday, March 26, 2004 11:55 AM
> >To: RPG programming on the AS400 / iSeries
> >Subject: RE: Loop code
> >
> >
> >John,
> >
> >At 3/26/04 12:12 PM, you wrote:
> > >I don't see anywhere that there are any holes in my code.
> > >
> > >Are you implying that the line
> > >C     myklist       chain     myfile
> > >is "if I feel like it, and I haven't chained before, chain. Otherwise,
> just
> > >skip this one?"
> > >The Chain will set the %eof condition when it is executed.
> >
> >   No it won't - CHAIN sets the %Found indicator, while READx sets the %EOF
> >(and %Equal) indicator.
> >
> >
> > >If the chain fails, the DOW(hile) will not execute, as it shouldn't.
> >
> >   That could be coincidence / luck - if there was a prior READx that set
> >the %EOF() indicator.
> >
> >
> > >It works very well on my system and the systems of thousands of my
> clients.
> >
> >   Then your systems have a compiler bug!  :)
> >
> >   -mark
> >
> >
> > >-----Original Message-----
> > >From: M. Lazarus [mailto:mlazarus@xxxxxxxx]
> > >Sent: Friday, March 26, 2004 10:31 AM
> > >To: RPG programming on the AS400 / iSeries
> > >Subject: Loop code
> > >
> > >
> > >John,
> > >
> > >   There are 2 holes in your code:
> > >
> > >1)  If the CHAIN fails the loop will still execute, probably displaying
> > >incorrect data.  CHAIN sets the %Found() flag.
> > >
> > >2)  If you will be executing this code more than once within the program
> > >the loop will probably NOT execute.  This is because the %EOF() condition
> > >will likely have already been set by the previous execution of this loop.
> > >
> > >   Changing the CHAIN to a SETLL/READE combo should fix the problem.
> > >
> > >   -mark
> > >
> > >At 3/26/04 11:12 AM, you wrote:
> > > >While his code would write a duplicate record at the bottom of the
> >subfile,
> > > >and your code may be efficient, my suggestion would be:
> > > >
> > > >C     myklist       chain     myfile
> > > >C                   dow       NOT %eof(myfile)
> > > >C                   eval      rrn = rrn + 1
> > > >C                   write     mysubfile
> > > >C     myklist       reade     myfile
> > > >C                   enddo
> > > >
> > > >JMHO
> > > >John Brandt
> > > >iStudio400.com
> > > >
> > > >-----Original Message-----
> > > >From: Marvin Radding [mailto:MRadding@xxxxxxxxxxxx]
> > > >Sent: Friday, March 26, 2004 9:58 AM
> > > >To: rpg400-l@xxxxxxxxxxxx
> > > >Subject: RE: RPG400-L Digest, Vol 3, Issue 231
> > > >
> > > >
> > > >
> > > >While there is nothing wrong with your code, I think this way is more
> > > >effiecient.
> > > >
> > > >C     myklist       setll     myfile
> > > >C
> > > >C                   dou       %eof(myfile)
> > > >C
> > > >C     myklist       reade     myfile
> > > >C                   if        %eof(myfile)
> > > >C                   iter
> > > >C                   endif
> > > >C
> > > >C                   eval      rrn = rrn + 1
> > > >C                   write     mysubfile
> > > >C
> > > >C                   enddo
> > > >
> > > >Marvin Radding
> > > >
> > > >
> > > >message: 1
> > > >date: Thu, 25 Mar 2004 14:32:35 -0800 (PST)
> > > >from: simafrog <SimaFrog@xxxxxxxxxx>
> > > >subject: SETLL ONE SLIGHT PROBLEM
> > > >
> > > >Actually I don't think I can do this here anyway. One problem remaining
> > > >is that the reade of the Detail file is causing one extra record to be
> > > >added to the work file, the last one of the batch is duplicated. Here
> is
> > > >the code:
> > > >  C           BLD       BEGSR
> > > >  C*
> > > >  C           OHKEY     SETLLORDHEDR             40
> > > >  C*
> > > >  C           *IN40     DOWEQ*OFF
> > > >  C*
> > > >
> > > >  C           OHKEY     READEORDHEDR                 40
> > > >  C           *IN40     IFEQ '0'
> > > >  C*
> > > >  C           C*
> > > >  C           ODKEY     SETLLORDDTL                   50
> > > >  C           *IN50     DOUEQ*ON
> > > >  C           ODKEY     READEORDDTL                   50
> > > >  C                     WRITEORDSWRKF
> > > >  C                     END
> > > >  C                     END
> > > >  C                     END
> > > >  C*
> > > >  C                     ENDSR