From: "ldries46" <bertus.dries@planet.nl>
Subject: Re: Garbage Collection ???
Date: Fri, 13 Apr 2012 21:27:23 +0200
Date: 2012-04-13T21:27:23+02:00 [thread overview]
Message-ID: <4f888010$0$2641$703f8584@news.kpn.nl> (raw)
In-Reply-To: <5o86o2smbjpz.17l849bmku28v$.dlg@40tude.net>
I have been trying to find the place where a faulty pointer could have been
introduced and I come to the conclusion that the return of a procedure in
the place.
I did position some variables (edge_debug1 till edge_debug4) to be filled
with the value of the original pointer at various places in and around the
procedure Edge_Force and printed them after the breakpoint.
The code there is now:
while edges /= NULL loop
edge_debug3 := edges;
Edge_Force(edges);
edge_debug4 := edges;
edges := edges.next;
end loop;
where Edge_Force code is:
procedure Edge_Force(edge1 : ptr_Edge) is
len : float;
begin
edge_debug1 := edge1;
len := Length(edge1.P1.pnt, edge1.P2.pnt) - edge1.l_init;
if abs(len / edge1.l_init) < 0.00001 then
len := 0.0;
end if;
edge1.force := edge1.k_s * len;
edge_debug2 := edge1;
end Edge_Force;
(gdb) print stedges
$43 = (access general.edge) 0x3e0d568
(gdb) print edges
$45 = (access general.edge) 0x0
(gdb) print edge_debug3
$48 = (access general.edge) 0x3db8200
(gdb) print edge_debug1
$51 = (access general.edge) 0x3db8200
(gdb) print edge_debug2
$53 = (access general.edge) 0x3db8200
(gdb) print edge_debug4
$55 = (access general.edge) 0x0
It can be seen that only the end of the procedure Edge_Force is between the
creation of edge_debug2 and edge_debug4
The reason that I originally thought about Garbage collection is that I
imagined that perhaps use of too much memory could be the reason.
Regards,
L. Dries
"Dmitry A. Kazakov" schreef in bericht
news:5o86o2smbjpz.17l849bmku28v$.dlg@40tude.net...
On Fri, 13 Apr 2012 14:14:43 +0200, ldries46 wrote:
> What also causes the changed value of edges within the loop. Can it be
> some
> garbage problem.
(Fortunately, Ada does not have mandated GC). Most likely you have a
dangling pointer somewhere.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2012-04-13 19:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-13 12:14 Garbage Collection ??? ldries46
2012-04-13 13:20 ` Dmitry A. Kazakov
2012-04-13 19:27 ` ldries46 [this message]
2012-04-13 20:06 ` Dmitry A. Kazakov
2012-04-13 22:49 ` Brian Drummond
2012-04-14 3:21 ` ldries46
2012-04-14 18:21 ` Robert A Duff
2012-04-18 9:07 ` Julian Leyh
2012-04-19 14:36 ` Robert A Duff
2012-04-19 20:26 ` Randy Brukardt
2012-04-20 7:11 ` Dmitry A. Kazakov
2012-04-21 0:46 ` Randy Brukardt
-- strict thread matches above, loose matches on Subject: below --
1992-04-22 18:55 Garbage collection? dog.ee.lbl.gov!overload.lbl.gov!agate!spool.mu.edu!yale.edu!jvnc.net!darw
1992-04-21 23:48 Robert I. Eachus
1992-04-21 23:02 Rick Hudson
1992-04-21 21:09 titan.ksc.nasa.gov!mcroberts
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