%ALLOC and pointers

[Frank.Kolmann@xxxxxxxxxx]

I want to thank Carsten Flensburg  and Scott Klement for their
invaluable help. I realise now that my confusion was not
understanding how ALLOC works with pointers.

I understood that pointers do not reserve memory,as such, so
I did not understand how one can use ALLOC and have a pointer
to the reserved memory.  Carstens example allowed me to see
the light. I have snipped parts of Carstens code to illustrate.
Another issue I did not understand is 'based' variables
and in this case based data structures.
I was under the mistaken impression that I needed to set
a pointer then move data from/to program variables.
The simplicity of just changing the pointer value and
viola the data is available to you in the variable escaped me.
Alloc and Realloc I am now, at last, able to understand and use.
The epiphany experience is a high that I cannot repay.
The best I can do is say thanks and it is a joy to learn from
the masters.


Frank Kolmann


-----  SNIP ---------------
Code from Carsten Flensburg

**-- Journal information:
D RJRN0100        Ds                  Based( pJrnInf )
D  RjBytRtn                     10i 0
D  RjBytAvl                     10i 0
D  RjOfsKeyInf                  10i 0
D  RjJrnNam                     10a
D  RjJrnLib                     10a
D  RjASP                        10i 0

-----  SNIP   ------------

 ApiRcvSiz  = 10240;
 pJrnInf    = %Alloc( ApiRcvSiz );

 DoU  RjBytAvl <= ApiRcvSiz;

   If  RjBytAvl > ApiRcvSiz;
     ApiRcvSiz  = RjBytAvl;
     pJrnInf    = %ReAlloc( pJrnInf: ApiRcvSiz );
   EndIf;