Re: Using Pointers

["M. Lazarus" <mlazarus@xxxxxxxx>]

At 10:52 AM 12/4/99 +1100, you wrote:

>Hello Mark,
>
>Since Jon hasn't answered this yet, I will.  Perhaps you are confused by 
>the fact that there is no explicit pointer definition for Array@.  Array@ 
>is a based pointer.  The compiler
>automatically defines any pointer used in a BASED definition.  (I think 
>that relying on this is sloppy and the programmer should code the pointer 
>anyway, but that's just me!)

  You got it - that's what threw me.

>The rest of the code is pretty straight-forward.  The only real problem 
>with such a technique
>is that array elements need to be the same size hence the "PADn" variables.

  They are the same size.  I thought the "PADn" variables were for 
illustration purposes, i.e. "other" fields.

  The way I'm understanding the rest of the code, assigning a regular field 
value to a pointer variable will automatically result in the pointer 
pointing to that variable's memory area. Correct?

  -mark


> > Date: Thu, 25 Nov 1999 00:03:41 +1100
> > From: "Mark Lazarus" <mlazarus@ttec.com>
> > To: RPG400-L@midrange.com
> > Reply-To: RPG400-L@midrange.com
> > Subject: Using Pointers
>
> >
> > Jon,
> >
> > At 09:44 AM 11/22/99 -0500, you wrote:
> >
> >  I followed the code until I got to Array@ !  Is there a "@" missing
> > somewhere?
> >
> > >The following technique (which does use pointers) could also work but I
> > doubt it
> > >is worth the effort. PS. The code sample here has been validated by
> > Code/400 but
> > >not tested.
> > >
> > >
> > >     D FakeRecord      DS
> > >     D  Elem1                         4    Inz('ABCD')
> > >     D  Pad1                         10
> > >     D  Elem2                         4    Inz('EFGH')
> > >     D  Pad2                         12
> > >     D  Elem3                         4    Inz('IJKL')
> > >     D  Pad3                          5
> > >     D  Elem4                         4    Inz('MNOP')
> > >
> > >     D ArrayPtrs       DS
> > >     D                                 *   Inz(%Addr(Elem1))
> > >     D                                 *   Inz(%Addr(Elem2))
> > >     D                                 *   Inz(%Addr(Elem3))
> > >     D                                 *   Inz(%Addr(Elem4))
> > >
> > >     D  Array                          *   Dim(4) Overlay(ArrayPtrs)
> > >
> > >     D CurrentElem     S              4    Based(Array@)
> > >     D Count           S              1  0
> > >
> > >     C                   For       Count = 1 to %Elem(Array)
> > >     C                   Eval      Array@ = Array(Count)
> > >     C     CurrentElem   Dsply
> > >     C                   EndFor

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