c++ - 'operator sockaddr *()' 在这里是什么意思？

Question

'operator sockaddr *()' 在这里是什么意思？Raw 类是一个内部类，sockaddr 是一个结构。

struct sockaddr
  {
    __SOCKADDR_COMMON (sa_);    /* Common data: address family and length.  */
    char sa_data[14];       /* Address data.  */
  };

class Address {
  public:
    //! \brief Wrapper around [sockaddr_storage](@ref man7::socket).
    //! \details A `sockaddr_storage` is enough space to store any socket address (IPv4 or IPv6).
    class Raw {
      public:
        sockaddr_storage storage{};  //!< The wrapped struct itself.
        operator sockaddr *();    // here
        operator const sockaddr *() const;
    };

  private:
    socklen_t _size;  //!< Size of the wrapped address.
    Raw _address{};   //!< A wrapped [sockaddr_storage](@ref man7::socket) containing the address.
.....
.....

标签： c++

Answer 1

这是一个用户定义的转换函数。类型的对象Raw可以隐式转换为sockaddr指针。例如以下将编译：

void fun(sockaddr *p); // function that takes a sockaddr pointer

Address::Raw r;
fun(r); // implicit conversion occurs from Raw in order to use function `fun`