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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,9640b17421044f1a
X-Google-Attributes: gid103376,public
From: steve quinlan <steven.quinlan@lmco.com>
Subject: Re: accesibility level problem
Date: 1999/02/19
Message-ID: <36CDE45C.5B5E04D8@lmco.com>#1/1
X-Deja-AN: 446220815
Content-Transfer-Encoding: 7bit
References: <36CD206A.32D96489@systems.at>
Content-Type: text/plain; charset=us-ascii
Organization: Lockheed-Martin Air Traffic Management
Mime-Version: 1.0
Newsgroups: comp.lang.ada
Date: 1999-02-19T00:00:00+00:00
List-Id: <comp.lang.ada>

My version of GNAT (3.11b) gives a different message :

 Non-local pointer cannot point to local object

 I think this is just standard accessibility rules. The type channelp is
defined at a package level, the object you are aliasing is defined locally
in a subprogram. It has a deeper level than the acces type -- it could go
out of scope, but objects of that access type could still be in scope, and
you could possibly assign the address of the object to a value of the access
type, thus creating the problem of an invalid reference. The accessibility
rules prevent even the possibility of this happening by not allowing
conversion of an access-to-object to a pointer-to-object when the pointer
may outlive the object (I think). So, it's an appropriate case for
unchecked_access.

You'd just want to make sure that in AwaitChannels, you don't save any of
those references in, say, some package body state variable. That could
generate the invalid reference problem.