Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rice!uupsi!cci632!mth
From: mth@cci632.UUCP (Michael Hickman)
Newsgroups: comp.sys.apollo
Subject: The wonderful Pascal compilier...
Message-ID: <43023@cci632.UUCP>
Date: 13 Nov 90 15:17:19 GMT
Reply-To: mth@cci.com (Michael Hickman)
Organization: none
Lines: 34


I have upgraded all of our machines to 10.3.  Last night a user tried running
a program I had written that generates a cross reference list of nets on a PCB. 

After the program ran all night (should have taken < 15 mins.) I killed it
figuring it needed to be recompiled under 10.3.  The program compiled fine,
but when I ran it, it barfed with an 'reference to illegal address (OS/MST 
manager)' on this:

    while not((this_net = nil) or 
              ((this_net^.plusminus = net.plusminus) and
               (this_net^.net_name  = net.net_name))) do

Looks like it tried evaluating the expression after the 'or' when the pointer 
was nil.  I changed it to this:

    while ((this_net <> nil) and 
       not((this_net^.plusminus = net.plusminus) and 
           (this_net^.net_name  = net.net_name))) do

It liked this, and the program ran.  However, another function that uses the EXACT
same line as example #1 above works fine with no changes.  Compilier optimization
level made no difference.

It bothers me that it worked fine before, but doesn't now.  I'm certainly no programming
guru, so if anyone can shed some light on this, please do.  Otherwise, this is just
another example of Apollo's great compilier technology.....


Michael T. Hickman     mth@cci.com
CAE/CAD Systems Administrator
Computer Consoles Inc.     
Rochester, NY            
(716)482-5000 x2913