Re: Getting into pointers

[Jon Paris <jon.paris@xxxxxxxxxxxxxx>]

I'm not sure why everyone has been using %Alloc in this scenario.   
Certainly it will work - but why bother?  There is no requirement for  
the storage of the DS to be based in order to pass a pointer to it as  
a parm.

It could more easily be done like this:

> Code simplified.
> D PGM2            PR                  EXTPGM ( 'PGM2' )
> D OutParm                         *
>
>
> D MyDS            DS                  LIKEDS ( gMyOtherDS ) DIM  
> ( 100 )

> D MyPtr           S               *   Inz(%Addr( MyDS ))
>
> /free
>
>  PGM2 ( MyPtr );

No allocation of memory or other messing around required. You can  
simplify it still further if you want and remove the definition of  
MyPtr and simply do the call as:

PGM2 ( %Addr( MyDS ));



Jon Paris

www.Partner400.com
www.SystemiDeveloper.com



On 12-Aug-09, at 9:58 AM, rpg400-l-request@xxxxxxxxxxxx wrote:

> Code simplified.
> D PGM2            PR                  EXTPGM ( 'PGM2' )
> D OutParm                         *
>
>
> D MyDS            DS                  LIKEDS ( gMyOtherDS ) DIM  
> ( 100 )
> D                                     BASED ( MyPtr )
> D MyPtr           S               *
>
> /free
>
>  PGM2 ( MyPtr );
>
> /end-free
>
>
>
> This crashed because I understand I need to allocate storage for  
> MyPtr before the call.
>
> So I inserted this and it worked :
> wLen  = %LEN ( wMrsAdh ( 1 ));
> MyPtr = %ALLOC ( wLen * 100 );
>
> Is this the right way to initialize the pointer?