From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=0.8 required=3.0 tests=BAYES_50 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
Date: 23 Jul 93 05:06:02 GMT
From: munnari.oz.au!comp.vuw.ac.nz!canterbury.ac.nz!news!otago.ac.nz!simon@uune
t.uu.net  (The Arch-Deviant)
Subject: Bug in VMS Ada 3.0?
Message-ID: <1993Jul23.180602.1@otago.ac.nz>
List-Id: <comp.lang.ada>

(This was asked a while ago but didn't receive any response. I'm trying
again on the grounds that (a) if it is a bug it seems quite a biggie and
(b) I'm looking forwards to hitting DEC with a problem report if I can :-) )

VMS Ada 3.0 appears not to perform range-checking when separate subunits
make use of global variables. Consider the following example:

   procedure Foo is
      subtype I_Range is integer range 1..10;
      A: array( I_Range ) of integer;
      I: I_Range;
      procedure Bar is separate;
   begin
      Bar;        -- Bar contains something like "A(I) := 0"
   end Foo;

The compiler does not generate any range-checking code in Bar, so that proc
will blindly write to whatever random memory location the unitialised index
I happens to point to, even if it is outside I_Range. If Bar is in the same
file then CONSTRAINT_ERROR will be raised as expected. My understanding
was that the program should perform equivalently regardless of which subunits
are in separate files. Am I missing something or have DEC made a mistake?
(And if the latter how the heck did this get past certification?)

Thanks...
 
Simon Brady                "So go ahead, put us down
University of Otago         The time will come when we turn it around
Dunedin, New Zealand        Won't be long, mark my words
                            The time will come for revenge of the nerds!"