RE: %EOF, %FOUND and the infamous Dow loop

["Phil" <sublime78ska@xxxxxxxxx>]

Using chain to position the file & read the first record, won't this work:


     C     key           chain     testfile
     C                   if        %found(testfile)
     C                   dow       not %eof(testfile)
     C
      * -- do whatever
     C
     C     key           reade     testfile
     C                   enddo
     C                   endif

Phil


> -----Original Message-----
> From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]On
> Behalf Of Joe Pluta
> Sent: Sunday, December 30, 2001 5:25 AM
> To: rpg400-l@midrange.com
> Subject: %EOF, %FOUND and the infamous Dow loop
>
>
> I did some researching back a ways, and I found that there have been a few
> discussions regarding the use of the file I/O BIFs.  It seemed to always
> revolve around which of the basic CHAIN/SETLL/READE loops you used.  Now,
> ever since I was able to, I've used the following standard code:
>
>       CHAIN
> *IN90 DOWEQ *OFF
>     (process)
>       READE
>       ENDDO
>
> This, I know, is only one of many possible variations, but it's
> the one that
> has always appealed to my sense of decorum.  This is definitely not a good
> argument for its use, but it has always worked quite nicely for me.  The
> only other mode I found nearly as appealing was the following:
>
>       SETLL
> *OFF  DOWEQ *ON
>       READE
> *IN90 IFEQ *ON
>       LEAVE
>       ENDIF
>     (process)
>       ENDDO
>
> This is basically the equivalent of the RCVF/GOTO loop I use in
> CL, with an
> unconditional loop and a LEAVE being the "structured" equivalent.  I'm not
> happy with the four extra lines of code, but hey, it's relatively
> efficient
> and has a couple of benefits, such as allowing the use of ITER.
>
> The second form can fairly readily be converted to use the file I/O BIF
> %eof, thereby removing indicator use.  The first, however,
> because the CHAIN
> and READE command set different BIFs, is a little harder.  Has anyone
> figured out a way to do it?  I tried to use (%found or not %eof)
> along with
> the operation extenders, and it seems to always return true (putting me in
> an infinite loop reprocessing the last record over and over).  Am
> I missing
> something here (more than usual)?
>
> Joe
>
>
>
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