bo. make unique with deleter

bo.cc

#include <memory>
#include <iostream>

namespace bo {
	template<typename T, typename Arg, typename Deleter = std::default_delete<T>>
	std::unique_ptr<T, Deleter> make_unique(Arg&& a, Deleter&& d = std::default_delete<T>()) {
		return std::unique_ptr<T, Deleter>(new T(std::forward<Arg>(a)), std::forward<Deleter>(d));
	}
}

class Bo {
public:
	Bo(int i) : i_(i) {}
	~Bo() { std::cout << "dtor ..." << std::endl; }
	void hello() const { std::cout << i_ << std::endl; }
private:
	int i_;
};

template <typename T>
struct deleter {
	deleter() {}

	void operator()(T* ptr) const {
		std::cout << "deleting ..." << std::endl;
		delete ptr;
	}
};

int main() {
	{
		const auto& b = bo::make_unique<Bo>(8, deleter<Bo>());
		b->hello();
	}
	std::cout << "out of scope" << std::endl;
	return 0;
}