From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: Legit Warnings or not
Date: Thu, 21 Jul 2011 11:13:01 -0400
Date: 2011-07-21T11:13:01-04:00 [thread overview]
Message-ID: <wcc8vrrbrb6.fsf@shell01.TheWorld.com> (raw)
In-Reply-To: j086nn$aau$1@tornado.tornevall.net
Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org> writes:
> There are 2 ways to handle such unconstrained objects. The easy way,
> which GNAT uses, is to allocate enough space for the largest
> variant. The harder way only allocates enough space for the current
> value, and actually changes the space of the object if the size is
> changed through an assignment.
Right. I know of two Ada compilers that used this
"deallocate-and-reallocate" method to change the size.
One of them got it wrong. I don't remember the details,
but I think it had to do with renaming a subcomponent,
and then an assignment to the whole record caused the
renaming to become a dangling pointer. The other compiler,
as far as I know, got it right.
> Some who have gone to the trouble to implement the 2nd way say they
> think it was the intention of the language designers.
Could be -- I don't know. I think for a low-level language like Ada,
it's probably not a good idea to introduce implicit heap allocation.
I'd at least want a way to turn it off.
Implicit heap allocation could be a good feature in a different
language, but then I'd want that language to allow:
type Tree is tagged
record
Left, Right : Tree'Class; -- doubly illegal!
end record;
- Bob
next prev parent reply other threads:[~2011-07-21 15:13 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-20 22:30 Legit Warnings or not Anh Vo
2011-07-20 23:16 ` Robert A Duff
2011-07-21 18:43 ` Anh Vo
2011-07-23 0:26 ` Randy Brukardt
2011-07-23 14:26 ` Robert A Duff
2011-07-21 2:37 ` Jeffrey Carter
2011-07-21 9:50 ` Brian Drummond
2011-07-21 14:39 ` Dmitry A. Kazakov
2011-07-23 0:36 ` Randy Brukardt
2011-07-23 9:03 ` Dmitry A. Kazakov
2011-07-23 11:07 ` Simon Wright
2011-07-23 11:21 ` Dmitry A. Kazakov
2011-07-26 21:25 ` Randy Brukardt
2011-07-27 7:45 ` Dmitry A. Kazakov
2011-07-28 0:37 ` Randy Brukardt
2011-07-28 9:22 ` Dmitry A. Kazakov
2011-07-28 14:22 ` Robert A Duff
2011-07-28 14:41 ` Dmitry A. Kazakov
2011-07-28 15:10 ` Robert A Duff
2011-07-28 17:05 ` Dmitry A. Kazakov
2011-07-28 23:32 ` Randy Brukardt
2011-07-28 23:48 ` Randy Brukardt
2011-07-29 6:57 ` Simon Wright
2011-07-29 18:56 ` Jeffrey Carter
2011-07-30 0:13 ` Randy Brukardt
2011-07-29 7:41 ` Dmitry A. Kazakov
2011-07-30 0:17 ` Randy Brukardt
2011-07-30 8:27 ` Dmitry A. Kazakov
2011-08-01 22:12 ` Randy Brukardt
2011-08-02 10:01 ` Dmitry A. Kazakov
2011-08-02 21:30 ` Randy Brukardt
2011-08-03 9:01 ` Dmitry A. Kazakov
2011-08-03 20:35 ` Randy Brukardt
2011-08-04 8:11 ` Dmitry A. Kazakov
2011-08-05 23:57 ` Randy Brukardt
2011-08-06 8:23 ` Dmitry A. Kazakov
2011-08-08 21:30 ` Randy Brukardt
2011-07-23 14:32 ` Robert A Duff
2011-07-26 21:32 ` Randy Brukardt
2011-07-21 15:28 ` Adam Beneschan
2011-07-21 15:41 ` Robert A Duff
2011-07-21 20:12 ` Adam Beneschan
2011-07-23 0:31 ` Randy Brukardt
2011-07-21 17:40 ` Jeffrey Carter
2011-07-21 21:30 ` Brian Drummond
2011-07-21 21:54 ` Adam Beneschan
2011-07-22 10:16 ` Brian Drummond
2011-07-22 14:54 ` Adam Beneschan
2011-07-23 0:46 ` Randy Brukardt
2011-07-23 0:42 ` Randy Brukardt
2011-07-23 9:20 ` Niklas Holsti
2011-08-04 5:56 ` David Thompson
2011-07-23 9:24 ` Dmitry A. Kazakov
2011-07-23 12:36 ` Brian Drummond
2011-07-21 15:13 ` Robert A Duff [this message]
2011-07-23 0:52 ` Randy Brukardt
2011-07-23 14:48 ` Robert A Duff
2011-07-21 14:17 ` anon
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