[boost] Re: Traits-based design and ODR

From: Andrei Alexandrescu (andrewalex_at_[hidden])
Date: 2002-04-29 21:01:11

"Gennadiy Rozental" <rogeeff_at_[hidden]> wrote in message
news:aakst6$i02$1_at_main.gmane.org...
> "Andrei Alexandrescu" <andrewalex_at_[hidden]> wrote in message
> news:aakk4t$613$1_at_main.gmane.org...
>
> [...]
> > 3. Put the specialized trait in a separate file, and ask everyone who
> wants
> > to use Widget to include that file. This is a discipline-based approach
> and
> > therefore is error-prone.
> >
> Here I disagree with you. Even if you have a third party Widget class (in
> other case you just put specialization there) you could always provide
> WidgetPtr.h header and use it everywhere instead of Widget.h. I do not see
a
> big problem with that.

I'd agree if the code would not compile. But there is a big problem: whether
you include widget.h or widgetptr.h, the code compiles. Might even link and
run in certain cases! Therefore, the error introduced would be very very
subtle.

I see the problem as huge, not big.

Andrei