[fpc-pascal] Pointers in Pascal!!

[Zaka E-Lab]

I have something like this:

PStruct = ^Struct;
Struct = record
          num    : integer;
          end;

I have a unit to handle that structure ( is a bit more complicated, but
is a good example), in this unit I have a procedure that deletes (
disposes ) the pointer. How can I know if a pointer are created or not?,
I mean, I don't wont to try to delete something that has not been
created yet, but I don't know how to do it, if that is possible.

Thanks a lot.

Zaka.