From: "Randy Brukardt" <randy@rrsoftware.com>
Subject: Re: Uninitialized out parameters.
Date: Wed, 6 Apr 2016 15:54:44 -0500
Date: 2016-04-06T15:54:44-05:00 [thread overview]
Message-ID: <ne3t2l$nl$1@loke.gir.dk> (raw)
In-Reply-To: c7t9gb1972nrm7e64hudekqvi5pmldtm17@4ax.com
"Dennis Lee Bieber" <wlfraed@ix.netcom.com> wrote in message
news:c7t9gb1972nrm7e64hudekqvi5pmldtm17@4ax.com...
...
>>The issue is rather, I think, whether V is returned at all.
>>There would have to be an assignment within the null procedure.
>>
> Which could be a case if the compiler used copy-in/copy-out semantics
> for scalars (or just copy-out for the test sample). GNAT, if I recall,
> uses
> reference semantics, and as out-only wouldn't be checking the initial
> value
> on entry.
Scalars in Ada are always by-copy, so the *effect* always have to be
copy-in/copy-out, regardless of how that's implemented. (I can't speak for
GNAT, but Janus/Ada makes copies at the call-site if we want to/need to use
by-reference parameter passing.)
The rules for whether an out parameter is initialized (and if so, how) are
complicated - see 6.4.1(12-15). 6.4.1(15) most likely applies in this case
(assuming no Default_Value aspect is involved), and that says that the value
is uninitialized. And of course the value of an uninitialized object can be
anything.
Randy.
next prev parent reply other threads:[~2016-04-06 20:54 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 12:02 Uninitialized out parameters ahlan
2016-04-05 13:17 ` rieachus
2016-04-05 14:07 ` ahlan
2016-04-06 9:45 ` Mark Lorenzen
2016-04-06 21:01 ` Jeffrey R. Carter
2016-04-07 7:10 ` ahlan
2016-04-05 16:19 ` G.B.
2016-04-06 8:19 ` ahlan
2016-04-06 10:17 ` G.B.
2016-04-06 11:44 ` Dennis Lee Bieber
2016-04-06 20:41 ` Niklas Holsti
2016-04-06 20:54 ` Randy Brukardt [this message]
2016-04-06 20:47 ` Randy Brukardt
2016-04-06 21:01 ` Randy Brukardt
2016-04-06 21:22 ` Dmitry A. Kazakov
2016-04-07 7:27 ` Randy Brukardt
2016-04-06 11:37 ` AdaMagica
2016-04-06 13:44 ` ahlan
2016-04-06 14:09 ` Mark Lorenzen
2016-04-06 14:10 ` G.B.
2016-04-06 20:53 ` Stefan.Lucks
2016-04-06 21:03 ` Randy Brukardt
2016-04-06 21:12 ` Niklas Holsti
2016-04-06 21:30 ` Randy Brukardt
2016-04-07 9:56 ` Stefan.Lucks
2016-04-07 16:08 ` AdaMagica
2016-04-07 23:02 ` Randy Brukardt
2016-04-08 7:32 ` Dmitry A. Kazakov
2016-04-07 7:52 ` Georg Bauhaus
-- strict thread matches above, loose matches on Subject: below --
1996-07-29 0:00 W. Wesley Groleau (Wes)
1996-07-18 0:00 Uninitialized "out" parameters Paul Whittington
1996-07-18 0:00 ` Robert Dewar
1996-07-19 0:00 ` Peter Amey
1996-07-20 0:00 ` Fergus Henderson
1996-07-20 0:00 ` Robert Dewar
1996-07-21 0:00 ` Fergus Henderson
1996-07-21 0:00 ` Robert Dewar
1996-07-23 0:00 ` Fergus Henderson
1996-07-23 0:00 ` Robert A Duff
1996-07-24 0:00 ` Fergus Henderson
1996-07-24 0:00 ` Fergus Henderson
1996-07-23 0:00 ` Richard A. O'Keefe
1996-07-23 0:00 ` Robert A Duff
1996-07-24 0:00 ` Richard A. O'Keefe
1996-07-24 0:00 ` Robert A Duff
1996-07-25 0:00 ` Richard A. O'Keefe
1996-07-25 0:00 ` Robert A Duff
1996-07-24 0:00 ` Theodore E. Dennison
1996-07-25 0:00 ` Frank Manning
1996-07-25 0:00 ` Richard A. O'Keefe
1996-07-26 0:00 ` Frank Manning
1996-07-23 0:00 ` Robert Dewar
1996-07-24 0:00 ` Robert A Duff
1996-07-24 0:00 ` Fergus Henderson
1996-07-24 0:00 ` Fergus Henderson
1996-07-25 0:00 ` Richard A. O'Keefe
1996-07-25 0:00 ` Robert A Duff
1996-07-18 0:00 ` Adam Beneschan
1996-07-18 0:00 ` Robert Dewar
1996-07-19 0:00 ` Dale Stanbrough
1996-07-19 0:00 ` James A. Squire
1996-07-19 0:00 ` Adam Beneschan
1996-07-20 0:00 ` Michael Feldman
1996-07-21 0:00 ` Fergus Henderson
1996-07-21 0:00 ` Michael Feldman
1996-07-21 0:00 ` Robert Dewar
1996-07-22 0:00 ` Fergus Henderson
1996-07-23 0:00 ` Michael Feldman
1996-07-23 0:00 ` Robert Dewar
1996-07-25 0:00 ` Fergus Henderson
1996-07-24 0:00 ` Fergus Henderson
1996-07-24 0:00 ` Robert A Duff
1996-07-25 0:00 ` Richard A. O'Keefe
1996-07-19 0:00 ` Adam Beneschan
1996-07-19 0:00 ` Samuel Tardieu
1996-07-19 0:00 ` John Herro
1996-07-19 0:00 ` Tucker Taft
1996-07-23 0:00 ` Peter Hermann
1996-07-23 0:00 ` Robert A Duff
1996-07-19 0:00 ` Pascal Obry
1996-07-19 0:00 ` Peter Hermann
1996-07-19 0:00 ` Michel Gauthier
1996-07-21 0:00 ` Robert A Duff
1996-07-19 0:00 ` Peter Amey
1996-07-21 0:00 ` Robert A Duff
1996-07-23 0:00 ` John Herro
1996-07-23 0:00 ` Robert A Duff
1996-07-23 0:00 ` Robert Dewar
1996-07-24 0:00 ` Peter Hermann
1996-07-26 0:00 ` Stephen J Bevan
1996-07-26 0:00 ` Robert A Duff
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