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=-1.9 required=3.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
Date: 21 Oct 92 23:47:59 GMT
From: pattis@beaver.cs.washington.edu  (Richard Pattis)
Subject: Uninitialized subtype variables
Message-ID: <1992Oct21.234759.24972@beaver.cs.washington.edu>
List-Id: <comp.lang.ada>

I cannot find anything in the LRM (mostly around 3.2.1) for Ada that says
after elaborating 
   X : NATURAL;
X's value is guaranteed to be >= 0. Is this in fact correct? Is there even a
guarantee that the bit pattern it contains can be interpreted as a
legal INTEGER?

Now, suppose I also declared PROCEDURE P (N : NATURAL); A smart compiler
could avoid checking the parameter constraint when calling P(X). But this could
lead to some interesting errors if X truly contained a negative value from its
(lack of) initialization.

Any comments?





-- 
------------------------------------------------------------------------------
  Richard E. Pattis			"Programming languages are like
  Department of Computer Science	 pizzas - they come in only "too"
    and Engineering			 sizes: too big and too small."