Re: Indicator Redux

["Peter Dow (ML)" <maillist@xxxxxxxxxxxxxxx>]

Hi Dave,

Maybe a little historical perspective would help.  RPG has always had 
just 99 indicators.  At some point, programmers were allowed to access 
them as if they were in an array (the *IN array).  After display files 
were introduced, they started eating up all the available indicators in 
order to position cursors, set display attributes and what not.  Pretty 
soon, there weren't enough indicators for both the display file and RPG.

The solution was to allow display files to have their own set of 99 
indicators.  This is done by specifying the INDARA keyword in the 
display file, and the INDDS keyword on the file spec in the RPG 
program.  Once you've done this, RPG has its 99 indicators in the *IN 
array, and the display file references the 99 indicators in the data 
structure specified in the INDDS keyword on the file spec.

Now it is possible to have the display file's indicator data structure 
overlay the *IN array, by making the data structure based, and having 
its basing pointer point to the beginning of the *IN array.  If you do 
this, you're back to one set of 99 indicators, which negates the 
intention of having a separate set of indicators.  And it's a waste of 
coding time, since you have the same effect by leaving off the INDARA 
and INDDS keywords.

The only reason I've ever seen for mapping a data structure to the *IN 
array is to allow naming the 99 RPG indicators so you don't have to use 
*IN34 or *IN(27), which are not very meaningful.  But you don't need to 
use INDARA or INDDS to do this.  Simply define a based data structure 
whose pointer points to the address of *IN01.  This data structure does 
NOT have to be specified in an INDDS keyword.  You don't even need a 
display file.  In other words, you could have a program with an INDARA 
display file where INDDS points to data structure ABC, and a separate 
based data structure XYZ that overlays the *IN array.  That way you can 
name the 99 RPG indicators and the 99 display file indicators.

hth,
*Peter Dow* /
Dow Software Services, Inc.
909 793-9050
pdow@xxxxxxxxxxxxxxx <mailto:pdow@xxxxxxxxxxxxxxx> /



Turnidge, Dave wrote:
> This "pointer" thing is new for me, as far as USING it is concerned. If
> I'm reading your code correctly, you are setting up a data structure
> over the *IN array. Yes? Where or how does this get related to the
> INDARR and INDDS? Would I use the *IN pointer method INSTEAD of INDARR
> and INDDS, or use both? 
>
> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Lapeyre, Francis
> Sent: Wednesday, December 06, 2006 10:34 AM
> To: RPG programming on the AS400 / iSeries
> Subject: RE: Indicator Redux
>
> I do it with a pointer, because I often have to condition things on the
> output specifications. But it will work on display files, as well.
>
>  
>
>        // Define indicators
>
>      D P_Indicators    S               *   Inz(%ADDR(*IN))
>
>      D Indicators      DS                  Based(P_Indicators)
>
>      D Update_Mode                         Like(*IN)
> Overlay(Indicators:01)
>
>       Begsr *INZSR;                                  
>                                                      
>       // List or update mode?                        
>       Update_Mode = (%PARMS > 0 And P_Update = 'Y'); 
>       Endsr;                                              
>
> Francis Lapeyre
> IS Dept. Programmer/Analyst
> Stewart Enterprises, Inc.
> E-mail: flapeyre@xxxxxxxx 
>
>
> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Turnidge, Dave
> Sent: Wednesday, December 6, 2006 10:12 AM
> To: RPG programming on the AS400 / iSeries
> Subject: Indicator Redux
>
> I have looked through the archives having to do with Indicator Arrays,
> and am confused. It appears that there are two arrays(?): one for
> display file indicators, and one for RPG indicators.
>
> When I started on my current project I was told that I didn't need to
> use the "pointer method" to define my indicators, but now I am running
> into a problem. I have set up variable "ExcludeSys" for position 27 in
> my indicator data structure. However, when I turn ExcludeSys *ON, *IN27
> is not *ON, and, I WANT it to be on. 
>
> Please help me understand the difference (if there is one) and/or how to
> be able to use a variable name and have the action continue on to the
> indicator. Also, if there is a page in a Redbook (or equivalent) that
> explains this from IBM's "easy to understand" viewpoint <G> a link would
> be nice...
>
> Thank you,
>
> Dave
>
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