[boost] Re: Re: 80% portable ptr<>

From: Philippe A. Bouchard (philippeb_at_[hidden])
Date: 2002-08-15 23:20:43

"David Abrahams" <dave_at_[hidden]> wrote:
> I don't see what point you're trying to make. The stuff you've quoted
> doesn't change anything. (T*)1 is either undefined or unspecified behavior
> for any T you choose; I forget which.
>
> From: "Philippe A. Bouchard" <philippeb_at_[hidden]>
> >
> > k = ptrdiff_t((char *) (T *) (U *) 1 - (char *) 1)
> > K is some constant

5.2.10.5:
A value of integral type or enumeration type can be explicitly converted to
a pointer.10) A pointer converted to an  integer of sufficient size (if any
such exists on the implementation) and back to the same pointer type will
have  its  original  value; mappings between pointers and integers are
otherwise implementation-defined.

This implies the value shall not be aligned when converted.  The constant is
thus irrelevant.

Philippe A. Bouchard