Re: Passing a MODS as a parameter

This is a simple faked-out version of the original code - which concludes by displaying the data in the final element. It works just fine.


H DftActgrp(*No)

D FDS DS Template
D #FmtNam 10A
D #FldLen 5I 0

D MainDS DS LikeDS(FDS) Dim(2000)

D RtvFlds PR
D QFlddta LikeDS(FDS) Dim(2000)

RtvFlds(MainDS);

Dsply ('Data from element 2,000 ' + MainDS(2000).#FmtNam
+ ' - ' + %Char(MainDS(2000).#FldLen) );

*InLr = *On;

P RtvFlds B

D RtvFlds PI
D FldDta LikeDS(FDS) dim(2000)

D i S 5I 0

For i = 1 to 2000;
FldDta(i).#FmtNam = 'Fld-' + %Char(i);
FldDta(i).#FldLen = i;
EndFor;

Return;

P RtvFlds E

On Feb 14, 2020, at 3:31 PM, Vernon Hamberg <vhamberg@xxxxxxxxxxxxxxx> wrote:

Hi Frank

Let me jump in late - seems to me there is no need to use pointers - and IRC, the calling program can maybe just use the array name without index in the call - again, this is dim (not dim-ension) memory. :)

Here is an example from a question on StackOverflow that seems to support my memory - this uses a template in PGM2, it could be changed to do that in PGM1 and have copy member in both.

Note that the call to PGM1 uses only the name of the array. It's a bit mixed up, but the point is (not pointer), the call to pass the array is simple here.

Here is the link to where I found this - https://stackoverflow.com/questions/41858768/how-do-i-pass-an-array-data-structure-as-a-parameter

|D PGM1 PI D ReceiveVar LikeDS(ResponseData) Dim(100) D ReceiveCount 10U 0 Const D PGM1 PR D ReceiveVar LikeDS(ResponseData) Dim(100) D ReceiveCount 10U 0 Const|

This is PGM2 - PR and PI omitted, might not be needed anymore.

|D ResponseData_t DS template D Field1 3 0 D Field2 26 D Field45 26 d myData ds likeds(ResponseData_t) dim(100) D PGM1 PR ExtPgm('PGM1') D ReceiveVar LikeDS(ResponseData_t) Dim(100) D ReceiveCount 10U 0 Const /FREE pgm1(myData:10); *INLR=*ON; return; /END-FREE|

On 2/14/2020 3:09 AM, Frank Kolmann wrote:

Thanks Jon and Brigitta

Thank you Jon.
I am quite aware how to process MODS.
I passed the pointer to the MODS as a parameter.
This worked. I was able to process the MODS fine. Now this no longer works, something has changed,

However, btw, I recoded to use an Array DS.
Well I am getting back ONLY the first DS(1), the first DS array element. The rest are empty.
I know that I am populating the DS array, I can see that in debug,

Appreciate any suggestion as to what I am doing wrong.


Code fragment of the PR and PI of the called progrzm

D RtvFlds PR N
D QDspFil 20A Value
D QNumFlds 10I 0
D QFlddta Like(FDS) Dim(2000)

D FDS DS Based (p_FDS) qualified dim(2000)
D #FmtNam 10A
D #FldNam 10A
D #FldLen 5I 0
D #FldPlen 5I 0
D #FldDec 1
D #FldIO 1
D #FldAtr 1
D #FldDTUS 1
D #FldEdt 20A
D #FldRow 10I 0
D #FldCol 10I 0
D #FldCom 4000A varying
*---------------------------------------------------------------*
* Retrieve Display File Fields *
*---------------------------------------------------------------*

P RtvFlds B Export



D RtvFlds PI Like(LglTyp)
D QDspFil Like( QNamTyp ) Value
D Numflds 10I 0
D FldDta Like(FDS) dim(2000)

In debug I can see FldDta has the correct information



Code from caller

D FDS DS QUALIFIED DIM(2000)

D #FmtNam 10A
D #FldNam 10A
D #FldLen 5I 0
D #FldPlen 5I 0
D #FldDec 1
D #FldIO 1
D #FldAtr 1
D #FldDTUS 1
D #FldEdt 20A
D #FldRow 10I 0
D #FldCol 10I 0
D #FldCom 1000A varying



D RTVFLDS PR N
D $FilQul 20 Value
D $NumFlds 10I 0
D $FldDtaDS Like(FDS) dim(2000)

*IN10 = RTVFLDS ($FilQul : #GotFlds : FDS);

In debug I can see that FDS has only the first element of the DS populated, all the rest are empty.

This is the first time I used DS arrays, and from what I see the same problem exists as the MODS problem.

Regards
Frank




On 13/02/2020 2:36 am, Jon Paris wrote:

Actually what is passed is the address of whatever occurrence was set at the time of the call.
If you did an Occur 1 before the call then it is the address of the first element.
Had you done some processing that left the current occurrence at (say) 20 before the call then the address of 20 would be passed.

The only way to process a MODS correctly when passed as a parm is to increment the occurrence_within_ the called routine.

But Birgitta is right - you should be using a DS array which will avoid all of the messiness. Basically MODS are deprecated - DS arrays are a much better approach.

On Feb 11, 2020, at 11:42 PM, Frank Kolmann<frank.kolmann@xxxxxxxxx> wrote:

Hi

A while back I wrote a program that uses QDFRTVFD api.
source is here
https://wiki.midrange.com/index.php/QDFRTVFD_%E2%80%94_Retrieve_Display_File_Description

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