Re: 'Size (novice question)

[lutz@iks-jena.de (Lutz Donnerhacke)]

* Florian Weimer wrote:
>   Put ("Boolean'Size (type):     "); Put (Boolean'Size); New_Line;
>   Put ("Boolean'Size (variable): "); Put (X'Size); New_Line;
>
>Almost no compiler will print 1 twice because on most architectures,
>access to individual bits is expensive in both time and space when
>compared to word or even octet access.

But the following code can not use compressed variables:

with Ada.Text_IO, Ada.Integer_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO;
procedure Size_Difference is
   X1, X2 : Boolean;
   A1, A2 : array (1..8) of Boolean;
   pragma Pack (X2,A2);  -- I know, that a named array subtype is packable.
begin
   Put ("Boolean'Size (type): "); Put (Boolean'Size); New_Line;
   Put ("Boolean'Size (X1):   "); Put (X1'Size); New_Line;
   Put ("Boolean'Size (X2):   "); Put (X2'Size); New_Line;
   Put ("Boolean'Size (A1):   "); Put (A1'Size); New_Line;
   Put ("Boolean'Size (A2):   "); Put (A2'Size); New_Line;
end;