From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
X-Received: by 2002:ac8:7ca1:: with SMTP id z1mr19027021qtv.254.1618947679779;
        Tue, 20 Apr 2021 12:41:19 -0700 (PDT)
X-Received: by 2002:a25:ccc1:: with SMTP id l184mr27262267ybf.165.1618947679628;
 Tue, 20 Apr 2021 12:41:19 -0700 (PDT)
Path: eternal-september.org!reader02.eternal-september.org!news.uzoreto.com!news.karotte.org!news2.arglkargh.de!news.mixmin.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: comp.lang.ada
Date: Tue, 20 Apr 2021 12:41:19 -0700 (PDT)
In-Reply-To: <s5n9r3$crn$1@franka.jacob-sparre.dk>
Injection-Info: google-groups.googlegroups.com; posting-host=35.245.252.196; posting-account=XfA3zgkAAABoz6fRf3Tehtnqqr7Ycml-
NNTP-Posting-Host: 35.245.252.196
References: <962020bb-97fc-42c3-8255-8f9b2bcbe204n@googlegroups.com>
 <s5mvrp$fu0$1@dont-email.me> <13f272e5-14a3-45cb-abf2-3d9f5a98f715n@googlegroups.com>
 <s5n9r3$crn$1@franka.jacob-sparre.dk>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <07a090e1-85b4-4ebb-a093-dcda57b56579n@googlegroups.com>
Subject: Re: 'address on a subprogram parameter
From: Vincent Marciante <vincent.marciante@l3harris.com>
Injection-Date: Tue, 20 Apr 2021 19:41:19 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Xref: reader02.eternal-september.org comp.lang.ada:61874
List-Id: <comp.lang.ada>

On Tuesday, April 20, 2021 at 3:25:25 PM UTC-4, Randy Brukardt wrote:
> "Vincent Marciante" wrote in message=20
> On Tuesday, April 20, 2021 at 12:35:07 PM UTC-4, J-P. Rosen wrote:=20
> > Le 20/04/2021 =C3=A0 17:10, Vincent Marciante a =C3=A9crit :=20
> > > I think that I used to know this but currently am not sure:=20
> > >=20
> > > Assuming the a value is passed by reference,
> You can only assume that for by-reference types (see RM 6.3(4-9)).=20
>=20
> Your example just used an unspecified record type. For any old record typ=
e=20
> (not in that list), the parameter passing mechanism is unspecified. Which=
=20
> means a compiler can pass by copy if it wants (it *probably* will pass by=
=20
> reference, but that's not the same as being required to do so). And if it=
=20
> does, your assumption doesn't hold.=20
>=20
> For instance, for a small record like:=20
> type Screen_Position is=20
> X, Y : System.Byte; -- A Janus/Adaism, but I think you get the point.=20
> end record;=20
> it might make more sense to pass by copy (especially if registers are use=
d=20
> in the usual calling convention).=20
>=20
> Randy.

Got it (and "no way" that the big record that is in the real code would be =
passed by copy
but I'll see if specifying it explicitly would not be disruptive).  Thanks.