Re: Field interpreted differently betweenphysicalandlogical

Barbara,

I guess it's the explicit part I'm having trouble with.  To me, I don't see 
where I have explicitly defined anything.  The qualified DS is defined based on 
the physical file and the logical files used in the program are externally 
described without any redefinition in the logical DDS.  Again, taking it's 
definition from the physical file.  If everything is being defined in terms of 
the physical file why are the defined differently in the program?  That's what 
is confusing me.

-----Original Message-----
From: wdsci-l-bounces@xxxxxxxxxxxx
[mailto:wdsci-l-bounces@xxxxxxxxxxxx]On Behalf Of Barbara Morris
Sent: Thursday, March 02, 2006 2:21 PM
To: wdsci-l@xxxxxxxxxxxx
Subject: Re: [WDSCI-L] Field interpreted differently
betweenphysicalandlogical


Rick.Chevalier@xxxxxxxxxxxxxxx wrote:
> <snip>
> If you don't explicitly define the field with a D spec, the compiler will 
> assign a default definition for the field.
> </snip>
>
> The I spec is created from an externally defined file.  Are you saying I need 
> to go backwards and define the file internally?  That doesn't make any sense.

No, making it program-described wouldn't help.  If you have a zoned
field on a program-described I spec, it would default to being packed in
the program same as an externally-described I spec.

>
> <snip>
> To get all your input fields to be defined internally the same way they are 
> defined in the file, use an externally-described data structure in your 
> calling program:
>    D               e ds                  extname(ISFQE201:ISFQE2R)
> </snip>
>
> How does this fit into the program though?  Is it merely to set the field 
> definitions?  The data structure in the copybook is defined as externally 
> described so aren't I already doing that?

Indeed, the external DS is merely to set the field definitions.  The one
in the copybook is setting a different set of fields (DS.X and DS.Y vs X
and Y).

>
> In reference to Matt's post, is it the QUALIFIED keyword that is causing the 
> problem?  I wanted the DS from the copybook qualified to avoid confusion 
> between actual file fields and DS fields in bound programs that use the 
> copybook for prototypes.
>

I think that was a good decision.  You are right to use QUALIFIED in the
copy file, because of potential conflict with programs it's copied
into.  If a particular program wants to get explicit definitions for the
unqualified names, it should define its own external ds.

This whole external-format vs internal-format is basic to RPG; it's in
RPG II and RPG III too.  Since an I spec doesn't define the field, you
can have the same field appearing on different I specs with different
numeric types:

IFILE1
I              1    5S 0        FIELD1
IFILE2
I              1    3P 0        FIELD1
IFILE3
I              1    2I 0        FIELD1

If FIELD1 is not defined explicitly, it would be packed(5,0) in the
program.  If it was defined explicitly, any of zoned(5,0), packed(5,0)
or integer(5,0) would be valid.


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