Does variable creation need Elaborate_Body?

Does variable creation need Elaborate_Body?

[Victor Porton]

package X is

  -- pragma Elaborate_Body;

  function F return Integer;

  procedure Init;

end X;

package body X is

  V: Integer;

  function F return Integer is
  begin
    return V;
  end;

  procedure Init is
  begin
    V := 123;
  end;

end X;

-------------------

Does the above program need Elaborate_Body pragma for elaboration of "V: 
Integer;"?

Intuitively, "V: Integer;" does nothing. But it is a declaration which needs 
to be elaborated.

Does it elaborate correctly without Elaborate_Body?

-- 
Victor Porton - http://portonvictor.org

Re: Does variable creation need Elaborate_Body?

[Victor Porton]

And what if we replace "V: Integer;" with "V: Integer := 11;"?

Victor Porton wrote:
> package X is
> 
>   -- pragma Elaborate_Body;
> 
>   function F return Integer;
> 
>   procedure Init;
> 
> end X;
> 
> package body X is
> 
>   V: Integer;
> 
>   function F return Integer is
>   begin
>     return V;
>   end;
> 
>   procedure Init is
>   begin
>     V := 123;
>   end;
> 
> end X;
> 
> -------------------
> 
> Does the above program need Elaborate_Body pragma for elaboration of "V:
> Integer;"?
> 
> Intuitively, "V: Integer;" does nothing. But it is a declaration which
> needs to be elaborated.
> 
> Does it elaborate correctly without Elaborate_Body?
> 
-- 
Victor Porton - http://portonvictor.org

Re: Does variable creation need Elaborate_Body?

[AdaMagica]

Am Mittwoch, 15. November 2017 03:10:57 UTC+1 schrieb Victor Porton:
> package X is
> 
>   -- pragma Elaborate_Body;
> 
>   function F return Integer;
> 
>   procedure Init;
> 
> end X;
> ...
> Does it elaborate correctly without Elaborate_Body?

The problem here is not the variable V in the body. The problem is the function F returning some value (might be anything). If the body of X has been elaborated before the call of F, there is no elaboration problem; in your case, V may be uninitialized if Init has not yet be called.
If F is called before the body of X has been elaborated, you get Program_Error (elaboration check), because the body of F is not yet known. Elaborate_Body guarantees that the body of X is elaborated together with the spec.

This body of X has the same elaboration problem:

package body X is

  function F return Integer is
  begin
    return 1;
  end;

end X;