Passing data structures as parameters in RPGIV

Steve

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Apr 9, 2009, 3:37:30 AM4/9/09

to

Hi,

I'm trying to pass a datastructure as a parameter from a program to a
service program. I'm trying to do it by passing a pointer to the data
structure from the callling program to the receiving program;

Calling program;

MoveOp.batchCard = batbat ;
MoveOp.From_OpCode = *blanks ;
MoveOp.To_OpCode = '0040' ;
MoveOp.ResetQty = *on ;
fnCreateMOP( %Addr(MoveOp)) ;

Receiving program;

p fnCreateMOP b
export
d fnCreateMOP
pi
d p *
const
d pm ds likeds(MoveOpDS) based
(p)

Unfortunately when I run it through debug and check the values in 'PM'
all of the fields are filled with '*'.

What am I doing wrong? Is there an easier way of doing it than
passing the datastructure as a pointer?

Thanks

Steve

Dr.Ugo Gagliardelli

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Apr 9, 2009, 4:03:54 AM4/9/09

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il 09/04/2009 9.37, Scrive Steve 43191376:

You shold pass the pointer by-value, specifying value on the pointer
argument, otherwise your called proc will receive the address of that
pointer.

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Steve

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Apr 9, 2009, 4:02:58 AM4/9/09

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Hi,

How do you do that??? It's early and I've not had enought coffee!!!

Thanks

Steve

Dr.Ugo Gagliardelli

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Apr 9, 2009, 5:39:29 AM4/9/09

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il 09/04/2009 10.02, Scrive Steve 43191376:

A procedure like:

D proc pr
D argptr * value

will pass the pointer argument by-value, so the pointer itself, while:

D proc pr
D argptr *

will pass the pointer argument by-reference, so the address of the
pointer argument

jb

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Apr 9, 2009, 5:51:09 AM4/9/09

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Wouldnt
fnCreateMOP( MoveOp) ;
simply pass the address of the ds? Then in your called program
pi
d pm ds likeds(MoveOpDS)
would get that pointer & associate pm with it? Just like any other RPG
program.

Jonathan.

Steve

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Apr 9, 2009, 6:56:43 AM4/9/09

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I tried it like that at first but it won't compile because it's not
defined as a parameter. That's the reason why I went for the pointer
to the data structure option......

jb

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Apr 9, 2009, 10:40:22 AM4/9/09

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> to the data structure option......- Hide quoted text -
>
> - Show quoted text -

How about
pi
d parm likeds(MoveOpDS)
d pm ds likeds(MoveOpDS)

then move parm into pm? You might not be able to make parm likeds in
that case & it could be hard to 'automatically' make the field long
enough in case someone makes changes so maybe

pi
d parm 10 (or any length since its
just used as a pointer)
d pm ds likeds(MoveOpDS) based(p)
d p *
then eval p=%addr(parm)

Jonathan

Barbara Morris

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Apr 22, 2009, 7:02:50 PM4/22/09

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Steve wrote:
>
> I tried it like that at first but it won't compile because it's not
> defined as a parameter. That's the reason why I went for the pointer
> to the data structure option......
>

Did your prototype and PI both define that parameter with LIKEDS? Could
you show the error messages you got from the compiler?

What Jonathan suggested should work.