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From: Thierry Lelegard <thierry.lelegard@canal-plus.fr>
Subject: Re: How pass a "null" as a parameter of anonymous access type
Date: Fri, 23 Mar 2001 10:05:54 +0100
Date: 2001-03-23T10:05:54+01:00	[thread overview]
Message-ID: <3ABB11F2.C35C58FD@canal-plus.fr> (raw)
In-Reply-To: 3ABA5AC3.4C6C7536@t-online.de

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> I want call a C-binding procedure which is defined as "procedure p (a :
> access X; b : access Y);"
> Both a or b may be a null pointer, but Ada say "null not allowed for
> anonymous access type".
> Any idea what to do ?

A hack (it works with GNAT, but may not with others, not defined by the
language):

    Null_Access : aliased X; -- don't access it !!
    for Null_Access'Address use System.Null_Address;

    ....

    P (Null_Access'Access, ...);

-Thierry
____________________________________________________________________________

Thierry Lelegard, "The Jazzing Troll", Email: thierry.lelegard@canal-plus.fr
CANAL+ Technologies, 34 place Raoul Dautry, 75516 Paris Cedex 15, France
Tel: +33 1 71 71 54 30   Fax: +33 1 71 71 52 08   Mobile: +33 6 03 00 65 75
____________________________________________________________________________

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  parent reply	other threads:[~2001-03-23  9:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-03-22 20:04 How pass a "null" as a parameter of anonymous access type Freddy
2001-03-22 21:02 ` tmoran
2001-03-25 21:32   ` Freddy
2001-03-26 14:31     ` How pass a Ted Dennison
2001-03-23  9:05 ` Thierry Lelegard [this message]
2001-03-25 21:33   ` How pass a "null" as a parameter of anonymous access type Freddy
2001-03-26 19:17     ` Mark Lundquist
2001-03-27 16:13       ` Alfred Hilscher
2001-03-27 16:53       ` Thierry Lelegard
2001-03-26 13:44 ` Marc A. Criley
2001-03-26 19:35   ` Mark Lundquist
2001-03-27 12:59     ` Marc A. Criley
2001-03-27 16:12       ` Alfred Hilscher
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