Re: Good/best way to enforce library-level instantiation a generic package

["Randy Brukardt" <randy@rrsoftware.com>]

"Vincent Marciante" <vincent.marciante@l3harris.com> wrote in message 
news:6bcc6133-8c8b-4252-a8e6-fd64a5eec2ca@googlegroups.com...
>I made a generic package that I want only to be instantiated at library 
>level.
> I'm working on compile-time a way to enforce that desire which involves 
> access
> type accessibility level checking but have not yet set it up correctly.
> Is there a better/standard way?

For Ada 95, deriving from Controlled does the trick, but that was eliminated 
(at substantial cost) in Ada 2005 and later.

I suppose you could use type String_Access (which is a library-level access 
type) for this:

   with Ada.Strings.Unbounded;
   generic
       ...
   package My_Generic is
       -- Real stuff here.

       Library-Level : constant aliased String := "Library-Level";
       Check : Ada.Strings.Unbounded.String_Access := Library_Level'Access;
            -- 'Access is illegal if My_Generic is not instantiated at the 
library level.
   end My_Generic;

String_Access is a silly type that isn't used in the spec of 
Ada.Strings.Unbounded, and thus shouldn't be there, but it does work for 
this use. :-)

You can of course use any library-level access type in your program for this 
purpose; I picked this one 'cause it is already sitting around.

Hope this helps.

                   Randy.