Re: Difference between RPG III and RPG IV with CHAIN

On 05/11/2009, at 8:59 AM, jmmckee wrote:

Doing a CHAIN to position and read the first record when multiple records were read just went to end of file, as I recall. Been too long.

Were we doing someting wrong that caused the RPG IV code to fail? This has really been bugging me for a long time. I couldn't find a reason for the bizarre behavior in my searching. It >may< have been an error when only one record with the matching subkey was found. Again, I just don't remember.

The RPG III technique, when transposed literally, will work in RPG IV. However, I suspect you tried a mix of the RPG III and RPG IV code that you showed. I suspect what you had was something like:

xxkey chain xxfmt
dow not %eof(xxfile)

xxkey reade xxfmt
enddo

or perhaps:

xxkey chain xxfmt
dow not %found(xxfile)

xxkey reade xxfmt
enddo

or perhaps:

xxkey chain xxfmt
dow %found(xxfile)

xxkey reade xxfmt
enddo


Forgetting that CHAIN does not set EOF--it sets FOUND, and READE does not set FOUND it sets EOF. Some combination of the above will be the cause of the behaviour your observed.

The RPG III technique is cheating and uses the same indicator (in your case LR) for two different tests: not-found on CHAIN and eof on READE.

Regards,
Simon Coulter.
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