Re: Unsigned Integer Restraint Errors

[Georg Bauhaus <bauhaus@futureapps.de>]

On Mon, 2007-03-12 at 08:07 -0700, frikk wrote:
> Hello Everyone!
> 
> I'm having a trivial difficulty with Ada. I am working with a 64 bit
> unsigned integer, and of course I would like to know if the input to
> this unsigned integer is out of range. I am having two issues.  The
> first is that I cannot get ada to raise a constraint error unless I
> make a subtype and state the range of being a finite number (but only
> in some circumstances, I'll explain in a second). 
> 
> procedure Prime_Bits is
>    -- Declare a 64 bit unsigned integer
>    type UNSIGNED_LONG_INT is mod 2**64;

> 
>    test := -5;

This first question is probably answered by LRM 3.4.5,
 19. For a modular type, if the result of the execution of a predefined
     operator is outside the base range of the type, the
     result is reduced modulo the modulus of the type to a value that
     is within the base range of the type.

HTH