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,FREEMAIL_FROM,
	INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,e80a1497a689d8a5
X-Google-Attributes: gid103376,public
From: "Vladimir Olensky" <vladimir_olensky@yahoo.com>
Subject: Ada and GC   (Was Re: Ammo-zilla)
Date: 1999/10/29
Message-ID: <s1iiolchr0877@corp.supernews.com>#1/1
X-Deja-AN: 541963209
References: <38120FAF.945ADD7D@hso.link.com>
 <slrn8156pm.pl.aidan@skinner.demon.co.uk> <7uutgd$87h$1@nnrp1.deja.com>
 <19991024.18033546@db3.max5.com> <38189268.43EB150F@mail.earthlink.net>
 <86ogdjtdwz.fsf@ppp-115-70.villette.club-internet.fr>
 <3818D4F0.92FC4DC9@mail.earthlink.net>
Organization: Posted via Supernews, http://www.supernews.com
X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3
Newsgroups: comp.lang.ada
X-Complaints-To: newsabuse@supernews.com
Date: 1999-10-29T00:00:00+00:00
List-Id: <comp.lang.ada>


Charles Hixson wrote in message <3818D4F0.92FC4DC9@mail.earthlink.net>...

> Also, and
>speaking particularlly to the point of garbage collection, I would
>prefer a collector that one could invoke as needed, or at least one that
>was easy to stop and start.  I believe that the gc calls within Java are
>"hints".
>


Probably Modula-3 GC (exists for more than 10 years) is  better "hint"
regarding user control over GC.

http://www.research.digital.com/SRC/m3sources/html/runtime/src/common/RTColl
ector.i3.html
http://www.research.digital.com/SRC/m3sources/html/runtime/src/common/RTColl
ectorSRC.i3.html

These references are also available from the  Modula-3 Language definition
page:
http://www.research.digital.com/SRC/m3defn/html/m3.html

There were some concerns  that as GC in Ada is not mandatory
 and it's implementation is up to Ada vendors then using it would
 lead to loosing portability (compiling and using code originally written
 for system with GC on  a system that does not have GC would lead
 to memory leaks).

To avoid such situation  Ada GC could be implemented not within the core
system but as separate package. When it  WITHed with the user program
than it could be invoked for TRACED  ACCESS TYPES.

So on systems without GC that code just could not be compiled and used
without
necessary changes.

In M3  references by default are traced and when one do not want to use GC
with them
they are marked as UNTRACED
(http://www.research.digital.com/SRC/m3defn/html/refs.html)

In Ada references by default are UNTRACED and could be set to TRACED to be
handled by the attached (WITHed) GC. Such approach would provide
compatibility
with the existing  Ada design and facilitate better Ada usage for general
type
applications (not  embedded ,real-time and safety critical where
unpredictable
delays caused by GC are unacceptable).

Regards,
Vladimir Olensky