Re: setting 'Size and unchecked conversion safe here?

[Marius Amado Alves <amado.alves@netcabo.pt>]

On 11 Feb 2005, at 23:38, Robert A Duff wrote:

> Marius Amado Alves <amado.alves@netcabo.pt> writes:
>
>> I need to store access-to-subprogram values in a 64-bit modular type.
>
> Why do you want to do that?

That's the container I have to store small values. It's in a database 
system called Mneson. Mneson is based on a graph. Vertices are 
represented thusly:

    type Vertex is record
       Tip : Natural_16;
       Cue : Modular_64;
    end record;
    for Vertex'Size use 80;
    pragma Pack (Vertex);

Small values are stored directly in the Cue. Mneson is my baby, so I 
can change it if necessary, but as I said I'd rather leave it that way.

> What do you mean by "works fine"?  Values convert from one to the other
> and back, and you get what you started with?

"Works fine" means the referenced subprograms are correctly reaccessed. 
But I don't know if the unused bits stay the same. That's what I'd like 
to know. Or if there is some means to ensure that.