Initializing shared_ptr member variable, new vs make_shared?

Question

When initializing a shared_ptr member variable:

// .h
class Customer
{
public:
  Customer();

private:
  std::shared_ptr something_;
}

//          


        

Answer 1

In this case, using make_shared is not just allowed, but it is better to use it. If you use new, it will allocate memory for your Customer somewhere and then memory for your shared_ptr somewhere else, storing both strong and weak references (for weak pointers and shared pointers). If you use the make_shared you would have only one place in memory with everything and therefore only one new.

I'm not sure that I was really clear, this was the purpose of the GotW #89, read it, it is well explained there.