Re: GtkAda Problem

["Nick Roberts" <nick.roberts@acm.org>]

On Sat, 17 Jul 2004 17:38:05 GMT, Bj�rn Persson <spam-away@nowhere.nil>  
wrote:

> Oliver Doerler wrote:
>
>> fidle_id := Gtk.Main.Idle_Add (fidle'access);
>>  gnatmake Message:
>> =>subprogram must not be deeper than access type
>
> Did you declare fidle inside the main subprogram? Move it to a package.  
> Idle_Callback is defined on what is called the library level. It's not  
> allowed to point to something on a deeper level, and what's inside a  
> subprogram is deeper. The rule is there to prevent pointers from  
> pointing to something that can go out of scope and disappear before the  
> pointer goes out of scope.
>
> I think most beginners try to do this and get confused. I know I did.

If it is possible to move fidle to a library-level package, fine. But
if it would be impractical to do so, I suspect using Unchecked_Access
is the best bet.

-- 
Nick Roberts