AW: Any gotchas using VARLEN fields?

["HauserSSS" <Hauser@xxxxxxxxxxxxxxx>]

Hi guys,

only EVAL or %LEN() change the length of variable length fields. MOVE or
MOVEL does not!

Birgitta

-----Ursprungliche Nachricht-----
Von: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]Im Auftrag von Bob Cozzi
Gesendet: Mittwoch, 20. Oktober 2004 03:36
An: 'RPG programming on the AS400 / iSeries'
Betreff: RE: Any gotchas using VARLEN fields?


Eval always changes/sets the length of the target.
MOVEL may change the length. I believe it makes things longer but not
shorter, but I'd have to look it up.
-Bob

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of M. Lazarus
Sent: Tuesday, October 19, 2004 7:57 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: Any gotchas using VARLEN fields?

Bob,

  Will a MOVEL or EVAL overwrite the length bytes?

  -mark

At 10/19/04 07:50 PM, you wrote:
>The only down-side is that the data in the extended area is not recoverable
>when the record is deleted. Data for the field is moved into the extended
>area when the "average length" is exceeded. That is the value you put on
the
>VARLEN(xx) keyword.
>Other than that... no issues that I've seen.
>-Bob
>
>
>-----Original Message-----
>From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
>On Behalf Of mlazarus@xxxxxxxx
>Sent: Tuesday, October 19, 2004 11:15 AM
>To: rpg400-l@xxxxxxxxxxxx
>Subject: Any gotchas using VARLEN fields?
>
>  Is anyone using VARLEN fields in DDS?  We are thinking of implemeting it
>in a few files that have some large, seldom used, text fields.
>
>1)  Do the leading length bytes always have to be taken into consideration
>or will an EVAL or MOVEx know where to put the data (similar to the VARYING
>keyword)?
>
>2)  Does the target length have to be set manually when updating the field
>or will RPG set it properly?
>
>3)  If the H spec and compile do not specify CVTOPT(*VARCHAR), will the
>program bomb on a read, even if the VARLEN field is not referenced in the
>pgm?
>
>  A search seems to turn up little useful information (from a big picture
>standpoint.)  Does anyone have a writeup, article, link, manual etc. they
>can send?
>
>  Thanks.
>
>  -mark

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