Path: utzoo!attcan!uunet!husc6!encore!xenna.UUCP
From: soper@xenna.UUCP (Pete Soper,,,)
Newsgroups: comp.lang.pascal
Subject: Re: Pointers..
Message-ID: <7476@xenna.Encore.COM>
Date: 2 Jun 89 03:19:30 GMT
References: <1150@draken.nada.kth.se>
Sender: news@Encore.COM
Lines: 21

From article <1150@draken.nada.kth.se>, 
  by d87-jse@nada.kth.se (Joakim Sernbrant):
> Talking about pointers, is there any reason why I shouldn't do this on
> a PC running DOS without multitasking:
> 
> while p <> nil do begin
>   dispose(p);
>   p := p^.next;
> end;
 
  Yes. You might want your program to have a chance to make you rich and
famous by being portable.
  A great many heap managers (like ours) would invalidate p after the dispose
so the link assignment would blow up. Why can't you put up with an extra
assignment to avoid this? Whether it is your unspecified DOS Pascal compiler or
whatever, the overhead of a dispose would likely overwhelm the cost of an 
extra assignment that avoided dereferencing p after it had been disposed.
----------------------------------------------------------------------
Pete Soper                                             +1 919 481 3730
arpa: soper@encore.com        uucp: {bu-cs,decvax,necntc}!encore!soper 
Encore Computer Corp, 901 Kildaire Farm Rd, bldg D, Cary, NC 27511 USA