Re: Getting modular type size in bits

[Lutz Donnerhacke <lutz@iks-jena.de>]

* Robert A Duff wrote:
> Jano <402450@cepsz.unizar.es> writes:
>> I want to know that the type size is 5. I'm aware of the 'modulus 
>> attribute, and 'size. If I understand correctly, 'size returns the size 
>> allocated by the compiler for the type (normally 8 in this case), not 
>> the _minimum_ size to allocate it (which is what I would need in that 
>> case).
>
> 'Size returns the minimum -- i.e. how big it would be if it were a
> component of a packed record.  That's 32 in this case.  If it were
> "mod 2**5", then Number'Size would be 5, not 8.

$ cat t.adb
with Ada.Text_IO;

procedure t is
   type A is mod 2**5;
   for A'Size use 8;
begin
   Ada.Text_IO.Put_Line(Natural'Image(A'Size));
   declare
      type B is new A;
   begin
      Ada.Text_IO.Put_Line(Natural'Image(B'Size));
   end;
end t;
$ ./t
 8
 8
$ _