On Wed, Jan 11, 2012 at 9:19 AM, Roman Perepelitsa <roman.perepelitsa@gmail.com> wrote:
2012/1/10 Vladimír Třebický <vladimir.trebicky@gmail.com>
On Tue, Jan 10, 2012 at 10:34 PM, Roman Perepelitsa <roman.perepelitsa@gmail.com> wrote:
2012/1/10 Vladimír Třebický <vladimir.trebicky@gmail.com>
boost::function<void(int)> f = boost::bind(boost::weak_fn(&Foo::bar, some_weak_ptr), _1); f(1);
It's it better to bind &Foo::bar directly?
boost::function<void(int)> f = boost::bind(&Foo::bar, some_weak_ptr, _1);
Much simpler in my opinion.
That cannot be done, boost::bind() indeed accepts references, pointers and shared_ptrs for member functions but doesn't accept weak pointers, because a weak pointer cannot be trivially converted to shared_ptr (or anything that leads to the corresponding class instance).
It can be done. In fact, it has already been done. See http://lists.boost.org/boost-users/2011/09/70647.php.
Nice. I like this. However, once you declare the get_pointer (plus ptr_adater and invoker) there's no way to specify what should happen if lock() returns empty shared_ptr. In the example "invoker" returns default value: R operator()() const { return ci_.first ? (ci_.first->*ci_.second)() : R(); } which may (a) not be possible (if R is not default-constructible) or (b) not desired (eg. if user wants an exception to be thrown). Do you think there would be a way to control the behavior? V.