From: "Matthew Heaney" <mheaney@on2.com>
Subject: Re: Memory leak - What the ...?
Date: Wed, 13 Oct 2004 10:45:38 -0400
Date: 2004-10-13T14:33:10+00:00 [thread overview]
Message-ID: <416d3ca6$0$36214$39cecf19@news.twtelecom.net> (raw)
In-Reply-To: mailman.304.1097670377.390.comp.lang.ada@ada-france.org
"Stephen Leake" <stephen_leake@acm.org> wrote in message
news:mailman.304.1097670377.390.comp.lang.ada@ada-france.org...
> Surely any halfway decent compiler would optimize these to be the
> same?
>
> Hmm. Perhaps declaring an object requires calling Initialize, Adjust,
> and Finalize, unless the compiler can _prove_ those subprograms have
> no side-effects, which it probably can't do. Is that your point?
Something like that. If I have this:
function Op return CT is --some controlled type
O : CT;
begin
O.X := ...;
return O;
end;
then local controlled object O must be Initialize'd when it is declared, and
Finalize'd when the scope of its declaration ends.
If you do it this way:
function Op return CT is
begin
return CT'(Controlled with X => ...);
end;
then the compiler can probably build the return value in place:
declare
O : CT := Op;
begin
This is similar to the return-value optimization in C++.
As another example, the AI-302 set functions Union, Intersection, etc, are
implemented this way:
function Union (L, R : Set) return Set is
Tree : Tree_Type; --ordered set uses red-black tree (a type which isn't
controlled)
begin
... -- build Tree
return Set'(Controlled with Tree);
end;
next prev parent reply other threads:[~2004-10-13 14:45 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-10 21:33 Memory leak - What the ...? Alex R. Mosteo
2004-10-10 22:05 ` Marius Amado Alves
2004-10-11 8:18 ` Alex R. Mosteo
2004-10-11 11:04 ` Marius Amado Alves
2004-10-11 13:02 ` Martin Krischik
2004-10-11 8:25 ` Martin Krischik
2004-10-11 8:56 ` Martin Dowie
2004-10-11 12:59 ` Martin Krischik
2004-10-11 1:40 ` Stephen Leake
2004-10-11 8:59 ` Alex R. Mosteo
2004-10-11 18:24 ` Stephen Leake
2004-10-12 3:02 ` Brian May
2004-10-12 8:45 ` Jean-Pierre Rosen
[not found] ` <mailman.282.1097576360.390.comp.lang.ada@ada-france.org>
[not found] ` <uvegkc.jrg.ln@skymaster>
2004-10-12 12:31 ` Marius Amado Alves
2004-10-12 14:47 ` Alex R. Mosteo
2004-10-12 16:05 ` Marius Amado Alves
2004-10-12 19:37 ` Björn Persson
2004-10-12 22:10 ` Marius Amado Alves
[not found] ` <416C5646.1020506@netcabo.pt>
2004-10-13 0:17 ` Stephen Leake
[not found] ` <u655f1ng9.fsf@acm.org>
2004-10-13 6:24 ` Marius Amado Alves
[not found] ` <416C00D6.90402@netcabo.pt>
2004-10-13 0:14 ` Stephen Leake
[not found] ` <416BAFA4.7020400@netcabo.pt>
2004-10-13 0:07 ` Stephen Leake
2004-10-13 13:45 ` Hyman Rosen
2004-10-14 9:15 ` Martin Krischik
2004-10-14 17:21 ` Hyman Rosen
[not found] ` <uis9f1nw3.fsf@acm.org>
[not found] ` <mailman.301.1097650377.390.comp.lang.ada@ada-france.org>
2004-10-13 7:40 ` Dmitry A. Kazakov
2004-10-13 17:44 ` Mark Lorenzen
2004-10-14 8:03 ` Dmitry A. Kazakov
2004-10-18 0:33 ` Brian May
2004-10-12 12:05 ` Alex R. Mosteo
2004-10-13 0:12 ` Stephen Leake
2004-10-13 8:39 ` Pascal Obry
2004-10-13 13:11 ` Memory leak - What the ...? - FOUND Alex R. Mosteo
2004-10-17 0:45 ` Memory leak - What the ...? Brian May
2004-10-13 0:32 ` Matthew Heaney
2004-10-18 0:26 ` Brian May
2004-10-13 0:27 ` Matthew Heaney
2004-10-13 7:58 ` Martin Krischik
2004-10-13 13:01 ` Alex R. Mosteo
2004-10-13 0:25 ` Matthew Heaney
2004-10-13 12:26 ` Stephen Leake
2004-10-13 14:45 ` Matthew Heaney [this message]
2004-10-13 23:45 ` Brian May
2004-10-14 1:33 ` Jeffrey Carter
2004-10-11 8:04 ` Martin Dowie
2004-10-12 10:47 ` Alex R. Mosteo
2004-10-12 15:07 ` Alex R. Mosteo
2004-10-13 14:53 ` Matthew Heaney
-- strict thread matches above, loose matches on Subject: below --
2004-10-11 9:50 Christoph Karl Walter Grein
2004-10-11 10:21 Christoph Karl Walter Grein
2004-10-14 4:30 Christoph Karl Walter Grein
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