LOCALANYPTR Variables

The pointer type localanyptr is similar to the type globalanyptr (or anyptr) in that it is assignment compatible with every pointer type and the value nil.

A localanyptr variable differs from a globalanyptr variable in that the compiler allocates it 32 bits instead of 64 bits. If your program does not use extended address pointers, you can save space by using localanyptr instead of globalanyptr.

Like a globalanyptr variable, a localanyptr variable is not bound to a specific pointer type. You can assign it any pointer-type value, but you can not assign it an extended address pointer that cannot be converted to a 32-bit value.

You can compare a localanyptr variable to any pointer-type value (even one that you cannot assign to it) with the operator = or >.

You cannot dereference a localanyptr.

Example

This program is the same as the one in the section “GLOBALANYPTR Variables ”, except that localanyptr replaces every occurrence of globalanyptr. The two programs work the same way, but this one takes less space.

PROGRAM prog (input);
 
TYPE
   iptr = ^integer;
   rec = RECORD
           f1, f2 : real;
         END;
   rptr = ^rec;
VAR
      v1,
      d1 : iptr;
      v2,
      d2 : rptr;
    anyv : localanyptr;
       b : Boolean;
 
BEGIN
   {Initialize v1 and v2}
   new(v1);
   new(v2);
   v1^ := 0;
   WITH v2^ DO BEGIN
      f1 := 0;
      f2 := 0;
   END;
 
   {Set anyv to v1 or v2, depending on b}
   read(b);
   IF b THEN anyv := v1 ELSE anyv := v2;
 
   {You cannot dereference anyv, because it is a localanyptr.
    This is how you can access its data:}
   IF anyv = v1 THEN BEGIN
      d1 := anyv;
      d1^ := d1^ + 1;
   END
   ELSE BEGIN
      d2 := anyv;
      WITH d2^ DO BEGIN
         f1 := 34.6;
         f2 := 91.2;
      END;
   END;
END.