From: Stephen Leake <Stephen.Leake@gsfc.nasa.gov>
Subject: Re: question about functions
Date: 2000/01/24
Date: 2000-01-24T19:03:25+00:00 [thread overview]
Message-ID: <uwvozl2hp.fsf@gsfc.nasa.gov> (raw)
In-Reply-To: r_mi4.1825$lN4.97071@newsread1.prod.itd.earthlink.net
"Matthew Heaney" <matthew_heaney@acm.org> writes:
> In article <un1q01s1n.fsf@gsfc.nasa.gov> , Stephen Leake
> <Stephen.Leake@gsfc.nasa.gov> wrote:
>
> > One alternate approach that is possible in Ada is to pass the result
> > as an 'out' parameter :
> >
> > procedure f (A, B : in T; C : out T);
> >
> > now you can do C'Address.
>
> C'Address is only defined if T is a by-reference type.
>
> See RM95 13.3 (16).
13.3 (16) is implementation advice; it suggests that X'Address be
useful in certain situations, including by-reference types.
X'Address is _defined_ in 13.3 (11), which says nothing about where it
may be useful. Hmm, I'm not clear if a subprogram parameter is an
"object" here, but I believe it is.
In any case, I have often successfully used 'Address on subprogram
parameters that are not of a by-reference type, with both ObjectAda
and GNAT, so at least some compilers go beyond the implementation advice.
-- Stephe
next prev parent reply other threads:[~2000-01-24 0:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-01-20 0:00 question about functions Pascal LEJEUNE
2000-01-20 0:00 ` Hyman Rosen
2000-01-20 0:00 ` David Starner
2000-01-20 0:00 ` Stephen Leake
2000-01-22 0:00 ` Andy
2000-01-22 0:00 ` Matthew Heaney
2000-01-24 0:00 ` Stephen Leake
2000-01-22 0:00 ` Matthew Heaney
2000-01-24 0:00 ` Mats Weber
2000-01-24 0:00 ` Stephen Leake [this message]
2000-01-25 0:00 ` Matthew Heaney
2000-01-27 0:00 ` Stephen Leake
2000-01-20 0:00 ` Tucker Taft
-- strict thread matches above, loose matches on Subject: below --
2000-01-21 0:00 Pascal LEJEUNE
2000-01-21 0:00 ` tmoran
2000-01-21 0:00 ` Samuel T. Harris
2000-01-21 0:00 ` Stephen Leake
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