On Wed, 15 Oct 2025 at 00:07, Tom Honermann <tom_at_[hidden]> wrote:
>
> On 10/14/25 4:49 PM, Ville Voutilainen via SG15 wrote:
> > On Tue, 14 Oct 2025 at 23:39, Tom Honermann <tom_at_[hidden]> wrote:
> >
> >> I would be very unhappy if any implementation made observe the default.
> >> But I find observe useful and see no reason to prohibit implementations
> >> from offering it.
> > Right. I do see such a reason, because the whole reason some of the
> > hardened implementations
> > were written to begin with is to guarantee that stdlib calls that
> > violate the hardened preconditions
> > aren't UB, ever.
>
> Sure, and implementors are free to not offer an observe semantic for
> hardened preconditions. I don't see a problem.

Right, and I do, because "are free not to offer an observe semantic"
is not a guarantee,
whereas existing practice is to offer a guarantee. I see it quite a
problem that WG21 is suggesting
to introduce UB where there was none before.