Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!oakhill!dover!norm!shelley
From: shelley@atc.sps.mot.com (Norman K. Shelley)
Newsgroups: comp.lang.eiffel
Subject: Class STRING bug
Message-ID: <2339@dover.sps.mot.com>
Date: 24 Jul 90 18:42:20 GMT
Sender: usenet@dover.sps.mot.com
Lines: 29

class NEW_STRING
inherit
	STRING;	-- notice that Create is not renamed
feature
... 
end; -- NEW_STRING

Object of class NEW_STRING does not use STRING's Create (or allocate) to
allocate some string storage space. When equal, putstring, etc. are applied to
this object, the system will crash with a segmentation error!

One way to solve this is to add the following to STRING's invariant:

not area.Void;

This will protect future heirs from this problem! Also, one could then take out
the check for "not area.Void" within the routine "count" as it is not
necessary.

If one allows "area.Void" then one must put many checks for "not area.Void" in
MANY more spots than the one it is currently in!!

Norman Shelley
Motorola - ATC
2200 W. Broadway AZ09/M350
Mesa, AZ 85202
...!uunet!motsps!atc!shelley
shelley@atc.sps.mot.com
(602) 962-2473