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From: nospam@thanks.com.au (Don Harrison)
Subject: Re: Can't export object of private type
Date: 1999/02/24
Message-ID: <F7nAwn.on@syd.csa.com.au>#1/1
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Newsgroups: comp.lang.ada
Date: 1999-02-24T00:00:00+00:00
List-Id: <comp.lang.ada>

Looks like everyone's a bit coy on this question. :)


The best workaround I've been able to come up with is to export an access 
variable to the singleton. For example,

  package Singleton is

    type Singleton_Type is tagged private;
    type Access_Singleton_Type is access all Singleton_Type'Class;

    procedure Do_Something (S: in Singleton_Type);

    S_Ptr: Access_Singleton_Type;

  private
    type Singleton_Type is tagged null record;
    S: aliased Singleton_Type;
  end;

initialising the access variable at elaboration ..

  S_Ptr := S.all'Access;

and using it in clients ..

  Do_Something (S_Ptr.all);



Any better suggestions? ..


(Of course, it would be easier if Ada just allowed you to export a variable 
of a private type from the same package. :)  Oh, well.



-- 
Don (Harrison).   donh at syd.csa.com.au