HP 3000 Manuals HP 3000 Manuals
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.