Re: Declaring the same DS in caller and callee

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

Kurt

I don't remember the circumstances, and it may have been in an earlier 
release - I have run into the need to declare the pointer and/or to 
initialize the pointer explicitly with the %addr() function. The syntax 
you give below seems to work most of the time, however. As I say, I 
don't remember where I've had the problem. But leaving out one or both 
items resulted in an MCH3601.

Vern

Kurt Anderson wrote:
> Despite the fact that I have used Based and pointers for a while now,
> it's surprising (or scary) how much I've learned in this thread.
>
> Whenever I had seen pointers used, this is how the D-specs generally
> were:
>      d pMyArray        s               *
>      d MyArray         s             10a   based(pMyArray)
>
> So whenever I read the help on Based, when it talked about creating a
> basing pointer, I thought it meant it was creating a connection between
> the variable (MyArray) and the pointer (pMyArray).
>
> However, I now realize that using D-specs like that is redundant.  It
> really only needs to be done like this:
>      d MyArray         s             10a   based(pMyArray)
>
> To add to my previous misunderstanding, I had thought "@" held special
> meaning (don't allocate) for Based.  Though I now see that "@" is a
> valid character to begin a variable name with, so it's really no
> different than using TEMPLATE as the pointer.
>
> I apologize if I added confusion to others on this topic.
>
> -Kurt
>
> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Simon Coulter
> Sent: Friday, February 13, 2009 1:34 PM
> To: RPG programming on the IBM i / System i
> Subject: Re: Declaring the same DS in caller and callee
>
>
> On 14/02/2009, at 3:35 AM, Kurt Anderson wrote:
>
>   
> > I wish the help for the BASED keyword would mention
> > that implicit definition would occur when supplying a Based parameter
> > that is not defined elsewhere.  (If it does exist somewhere, someone
> > please point it out to me.)
> >     
>
>
> See the Chapter 15 of the ILE RPG Reference (any release supporting  
> BASED):
>
> "BASED(basing-pointer-name)
> When the BASED keyword is specified for a data structure or stand- 
> alone field, a basing pointer is created using the name specified as  
> the keyword parameter."
>
> Seems clear enough.
>
> Regards,
> Simon Coulter.
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