From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: CONSTRAINT ERROR: erroneous memory access
Date: Sun, 7 Jun 2020 10:51:44 +0200
Organization: Also freenews.netfront.net; news.tornevall.net;
 news.eternal-september.org
Message-ID: <rbi9r1$fuc$1@dont-email.me>
References: <d0ff83ad-a216-4fd6-b0ff-ef51a7c27d48o@googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Sun, 7 Jun 2020 08:51:45 -0000 (UTC)
Injection-Info: reader02.eternal-september.org;
 posting-host="b243c502e7d88efa94d0bed85751046f";
	logging-data="16332"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX1+ldWgLRJThyr/ygg0rDHMCjXa8tWaNjnk="
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.8.0
Cancel-Lock: sha1:Y/+nkSTMnIXaNoBlOK8HVvtV23A=
In-Reply-To: <d0ff83ad-a216-4fd6-b0ff-ef51a7c27d48o@googlegroups.com>
Content-Language: en-US
Xref: reader01.eternal-september.org comp.lang.ada:58995
Date: 2020-06-07T10:51:44+02:00
List-Id: <comp.lang.ada>

On 6/7/20 1:40 AM, jcupak@gmail.com wrote:
> It has been a few years since I have written Ada; I used and taught Ada 95 back when I was working for a defense contractor. But, now that I'm retired, I wanted to get up to speed with Ada 2012, so I decided to implement a main program to see how the Shortest_Paths generic package works (taken from A.18.31, pages 574-576). But, when I read in the data and call the Shortest_Path function, it returns with CONSTRAINT ERROR: erroneous memory access. I've tried multiple times, but can't seem to figure out what I'm doing (or NOT doing) wrong.

Actually ARM A.18.32: 
http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-A-18-32.html

Since you're using Ada 12, you must be using GNAT. With its default options, 
GNAT is not an Ada compiler. You need to add -gnatan -fstack-check to obtain 
full Ada semantics. (Technically, you also need -gnatE, but that doesn't affect 
the behavior of a properly elaborated program.) With those options, I suspect 
you'll get Storage_Error, which might be easier to understand.

-- 
Jeff Carter
"How'd you like to hide the egg and gurgitate
a few saucers of mocha java?"
Never Give a Sucker an Even Break
101