Article #15964: NORMALIZING POINTERS

 Technical Notes Database

TN964D.txt   NORMALIZING POINTERS
Category   :Pascal
Platform    :All
Product    :Turbo Pascal  4.0+

Description:
Q. How do I normalize a pointer in Turbo Pascal?
A. When you allocate a pointer, it is already normalized.  So, if
   you're SURE that you won't be making the offset greater than 64K,
   you can skip the normalizing step.

      PROCEDURE Normalize(VAR P);
      VAR pt : Pointer ABSOLUTE P;
      BEGIN
        Pt := Ptr(seg(pt^) + (ofs(pt^) DIV 16), ofs(pt^) MOD 16);
      END;

  You CAN perform pointer arithmetic, if you're desperate to do
  "C things" in Pascal.  Just normalize the pointer (maximize segment,
  minimize offset), typecast it to a LongINt, and do your math.  E.g.

      Normalize(recptr);
      Inc(LongInt(recptr), SizeOf(rec));

  where recptr is a pointer to a record, and rec is the record variable.


Reference:


7/16/98 4:35:38 PM
 

Last Modified: 01-SEP-99