Re: CONSTRAINT_ERROR - why?

[Alfred Hilscher <Alfred.Hilscher@t-online.de>]

Jeffrey Carter schrieb:
> 
> Alfred Hilscher wrote:
> > This program raises exception CONSTRAINT_ERROR for the second
> > assignment. It happens with GNAT 3.13p and 3.14p (on windows).
> >
> > Can someone explain why? Is this a compiler error or do I misunderstand
> > something?
> 
> The reason Constraint_Error is raised is because the code violates a
> constraint.
> 
> Why are you using Interfaces.C if you're not interfacing with C?


I extracted the example from a big (really big) application where heavy
use off (hardware-) manufacturer provided dlls is done.

 
> Since the LHS of your assignment is type Byte, the expression is
> evaluated using
> 
> function "/" (Left, Right : Byte) return Byte;
> 
> The value passed to Left is not in the range of Byte. If you want this
> evaluated as a universal expression, you have to add a step:
> 
> declare
>     Value : constant := X'Size / 8;
> begin
>     Y := Value;
> end;


Is there no way to avoid this extra assignment? I expected something
like function "/" (Left, Right : universal_integer) return Byte;


> --
> Jeff Carter
> "Why don't you bore a hole in yourself and let the sap run out?"
> Horse Feathers