RE: Two reade loops: which one preferred ?

CHAIN sets the %found indicator. You'd have something like

Key chain file
If %found
   Dou %eof
      ... process
      Key reade file
   Enddo
Endif

That effectively hides the intention of the loop (%found in one place %eof
in another). I think the setll/reade/dow is a mentally "cleaner" approach.

It also brings back the discussion of "use chain for single reads; use
setll/reade for multiple reads".

Loyd
   

-----Original Message-----
From: Vern Hamberg [mailto:vhamberg@xxxxxxxxxxxxxxxxxxxxxxxxx] 
Sent: Friday, November 21, 2003 11:37
To: Midrange Systems Technical Discussion
Subject: RE: Two reade loops: which one preferred ?

OK, I'm doing C these days and haven't done free-form RPG. Is CHAIN gone? 
Why the SETLL-READE combination, when CHAIN is equivalent?

Key chain file
Dow not %eof
    ...do whatever
Key reade file
Enddo

....

Vern

At 10:41 AM 11/21/2003 -0600, you wrote:
>In this case, you've removed a read, but complicated the code with multiple
>exit conditions. In this code:
>
>Key setll file
>Key Reade file
>Dow not %eof
>...process record...
>Key reade file
>Enddo
>
>There is an additional read, but only one exit condition (and exit
condition
>check). The loop is executed 0 or more times.
>
>In your example, you must code two exit conditions because of the DOU. The
>code is executed 1 or more times.
>
>Like Jon said, a priming read determines if there is any data in the file
to
>process. With DOW, we know immediately whether we should continue
processing
>the file. With the DOU, we don't know if there's data to process until
we're
>in the loop; hence, two exit conditions.
>
>Loyd Goodbar