I'm not entirely sure if the initialized(T const&) constructor would need an "explicit" keyword. What do you think? Should the following be forbidden?
boost::initialized<int> i = 42;
If so, we might as well make it even more explicit, by adding a "tag" parameter of type direct_initialized_t to the constructor, as I proposed before at https://svn.boost.org/trac/boost/ticket/3472 so that users would have to explicitly specify that they want direct-initialization:
boost::initialized<int> i(42, boost::direct_initialized);
Steven Watanabe wrote:
I'd much prefer boost::initialized to simply forward constructor arguments.
Thanks, Steven. But would it be okay to you if boost::initialized<T> would just have a initialized(const T&) constructor? Or do you think it should be a "variadic" one, for example initialized(const U&...). I'm afraid it's hard to implement such a variadic constructor, perfectly forwarding its arguments to the internal T object, given current limitations of a lot of compilers. And personally I think it would be sufficient to just offer a initialized(const T&) constructor. But please tell me if you think otherwise.
The templated constructor should be explicit, because otherwise things like
boost::initialized<std::vector<int> > v = 10;
would compile.
Please note that I never suggested to make your example compile. I was only wondering whether or not the following should compile: boost::initialized<std::vector<int> > v = std::vector<int>(10); So in fact, after initialization by means of initialized(const T&), lhs and rhs will have the same value. In that case, isn't copy-initialization appropriate? Kind regards, Niels -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center