How to initialize non-movable and non-copyable class member - boost::optional

Question

I have a non-movable and non-copyable type:

struct A
{
    A(std::string p1, int p2){}
    A(A const &) = delete;
    A(A&&) = delete;
    A& operator=(A const &) = delete;
    A& operator=(A&) = delete;
};

I can construct boost optional this way:

boost::optional<A> op(boost::in_place("abc", 5));

I also need to initialize boost::optional<A> which is a class member. Here is my solution:

class B
{
public:
    B(const boost::optional<A>& op): op_(op) {} 
private:
    const boost::optional<A>& op_;
};

B b(boost::optional<A>(boost::in_place("abc", 5)));

Is it possible to have just boost::optional<A> class member and initialize it somehow ?

Edit (clarification) I would like to have boost::optional<A> op_ class data member but I don't know how to initialize it.

Answer 1

You can declare the constructor of B as

class B {
  public:
      B(std::string p1, int p2) :
         op_(boost::in_place<A>(std::move(p1), p2)) {}

  private:
    const boost::optional<A> op_;
};

and instantiate B as

B b("abc", 5);

Note that I change the data member op_ to not be reference here, as opposed to the definition of B in your question.