Re: Getting into pointers

David,

Scott used MyPtr = %addr(MyDS); becuase in his example PGM1 allocated
the space for the DS automatically, thus it was not BASED.

However, it seems as if you have PGM2 allocating the space.

This is probably not a good idea. In fact, if PGM2 ends with LR=*ON,
you've got a real good possibility of corrupting memory.

How are you having PGM2 allocate the space?

Charles

On Wed, Aug 12, 2009 at 10:24 AM, David FOXWELL<David.FOXWELL@xxxxxxxxx> wrote:

Hi Scott,

My question: Why did you use the BASED keyword?  Why bother
using BASED and then %ALLOC?  Why not just do this?

D MyDS            DS                  LIKEDS ( gMyOtherDS )
DIM ( 100 )
D MyPtr           S               *

    MyPtr = %addr(MyDS);
    PGM2(MyPtr);

Why tell the OS to let you handle the allocation if you're
just going to allocate the exact size of the structure?

I'm afraid the answer to those questions is lack of experience/ignorance.

I feel I'm getting the hang of it though.

I now have something like

D MyDS            DS                  BASED ( MyPtr )
D MyPtr           S               *

   PGM2(MyPtr);

I've got rid of the BASED keyword in PGM2. I've kept it in PGM1 so that MyDS will be usable when PGM2 returns. Is that reasonable?

Can you explain why did you do this :

    MyPtr = %addr(MyDS);

Before the call? In my case it's PGM2 that creates the DS and sends back the pointer to PGM1.

Thanks.
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