Re: CONSTRAINT_ERROR - why?

["AG" <ang@xtra.co.nz>]

"Alfred Hilscher" <Alfred.Hilscher@t-online.de> wrote in message
news:3DFB89BF.323CB3E3@t-online.de...
>
>
> Robert A Duff schrieb:
> >
> > "James S. Rogers" <jimmaureenrogers@worldnet.att.net> writes:
> >
> > > "Alfred Hilscher" <Alfred.Hilscher@t-online.de> wrote in message
> > > news:3DFB7841.F898C02@t-online.de...
> > > > 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?
> > > >
> > > > I would expect that the computation is done first and then the
result
> > > > (33 which is successfully assigned the statement before) is
assigned.
> > > > But it seems that the size (=264) is assigned before the division is
> > > > executed.
> >
> > The 'Size is implicitly converted to BYTE, and then the "/" operator of
> > type BYTE is used.  You want to do the division in, say, Integer,
> > and then explicitly convert to BYTE, like:
> >
> >     ... := BYTE(Integer'(Fac_Conf_Struct'Size / 8));
>
> Shouldn`t the conversion take place _after_ the computation?

No. Because you need to know *which* division to use.
And that depends on the types used ...