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From: Thierry Lelegard <thierry.lelegard@canal-plus.fr>
Newsgroups: comp.lang.ada
Subject: Re: How pass a "null" as a parameter of anonymous access type
Date: Fri, 23 Mar 2001 10:05:54 +0100
Organization: CANAL+ Technologies
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Date: 2001-03-23T10:05:54+01:00
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Il s'agit d'un message multivolet au format MIME.
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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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