Re: [Boost-users] [optional]

Subject: Re: [Boost-users] [optional]
From: Gevorg Voskanyan (v_gevorg_at_[hidden])
Date: 2009-05-06 10:38:00

Dominique Devienne wrote:
> > boost::none will be helpful as well:
> > f(p1, p2, boost::none, p4);
> 
> Beside the headers, Google doesn't yield documentation on boost::none.
> 
> Could someone please explain it's intended use? I see none_t is a
> typedef to a member of none_helper, a struct with no members, and none
> is a const none_t, but I'd expect such a pointer to not be convertible
> to anything, so I'm not following on passing boost::none to a
> boost::optional as above, nor can't figure out the use for none. Can
> someone please provide some details / background info on none? Thanks,
> --DD

This is described in the documentation of boost.optional, here:
http://www.boost.org/doc/libs/1_39_0/libs/optional/doc/html/boost_optional/detailed_semantics.html#reference_optional_constructor_none_t

Best Regards,
Gevorg