RE: Pointer arithmetic

[Buck Calabro <mcalabro@xxxxxxxxxxxx>]

On Wednesday, April 29, 1998 1:47 PM, David Morris 
[SMTP:dmorris@plumcreek.com] wrote:

> Does anyone know if the following should work?  Based on the manual
> I think it should work I faintly remember doing this in the past,
> but I can't get to work now.
>
> D OffSet                        10I 0
> D Ptr1                            *
> D Ptr2                            *
> ...
> C                   EVAL      OffSet = Ptr1 - Ptr2
>
> I get the following message:
>
> *RNF7421 30      1 Operands are not compatible with the type of
> operator.

-snip-

> What am I missing here?  I have coded a work-around but I want to
> understand why this doesn't work.

Are these fields part of a data structure, or should they really be 
standalone?  In any event, I'm not having a problem at v4r1 and 
v4r2...  Here's my test; perhaps you're trying something very 
different.  I'm quite certain that you have more RPG IV experience 
than I do!

D CharTest1       S              1    Based(Ptr1)    
D CharTest2       S              1    Based(Ptr2) 
D Alphabet        S             26 
   INZ('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
D OffSet          S             10I 0 
D Ptr1            S               * 
D Ptr2            S               * 
 
   
C                   Eval      Ptr1=%addr(Alphabet) 
C                   Eval      Ptr2=%addr(Alphabet)+5 
C                   Eval      CharTest1=%str(Ptr1) 
C     CharTest1     Dsply 
C                   Eval      CharTest2=%str(Ptr2) 
C     CharTest2     Dsply 
C                   EVAL      OffSet = Ptr1 - Ptr2 
C     Offset        Dsply 
C                   Seton                                        LR 

hth
Buck

Buck Calabro
Commsoft, Albany, NY
mailto:mcalabro@commsoft.net

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