What is the best way to implement the adaptor pattern in c++

I have seen that it is possible to use inheritance, such as:

class A {
};

class Legacy{
};

class B : public A, private Legacy {
};

But it is weird to me to inherit public and private from two different classes. Is there an alternative way to implement the adapter pattern?

Generally it is better to use composition instead of inheritance for adapters (and many other cases too):

class B : public A {
  public:
    /* implementation of abstract methods of A with calls to Legacy */

  private:
    Legacy m_leg;
};