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From: Pascal Ledru <Ledru#m#_Pascal@MSMAIL3.HAC.COM>
Subject: Re: C->Ada: Converting char* to unsigned long
Date: 1996/05/16
Message-ID: <319B8E99.1910@MSMAIL3.HAC.COM>#1/1
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references: <319B3021.41C67EA6@is2.nyu.edu>
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organization: Hughes Aircraft Company
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newsgroups: comp.lang.ada
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Date: 1996-05-16T00:00:00+00:00
List-Id: <comp.lang.ada>


As you noticed the problem comes from the fact that you cannot 
instantiate Unchecked_Conversion (or any generic) with an 
unconstrained type.

There is probably a simpler solution but the following will work:

with Text_IO;
with Interfaces.C.Strings;
use  Interfaces.C.Strings;
procedure convert is

  package Integer_IO is new Text_IO.Integer_IO(Integer);

  C : chars_ptr;
  I : Integer;

  subtype Short_String is String(1..4);
  S : String(1..4);

  function To_Integer is new Unchecked_Conversion
    ( Source => Short_String,
      Target => Integer );

begin
  C := New_String( Str => "AAAA" & ASCII.NUL ); -- char*
  S := Value( Item => C);
  Integer_IO.Put( Item => To_Integer(S), Base => 16 );
  Text_IO.New_Line;
end;