anchor.diff:  	  (%ff-bind file-descriptor sockaddr-in (cffi:foreign-type-size '(:struct sockaddr-in))))
   	
   	(%ff-listen file-descriptor backlog)
  -	socket))))
  +	(make-instance 'ipv4-tcp-server
  +		       :host-address host-address
  +		       :port port
  +		       :socket socket)))))
  
positive.code: 			      ,@body)
         ,family ,host-address ,port)))
  
  (defclass ipv4-tcp-server (posix-socket)
    ((host-address
      :initarg :host-address
      :reader host-address)
     (port
      :initarg :port
      :reader port)))
  
  (defun make-ipv4-tcp-server (host-address port &key (backlog 5))
    (let ((socket (make-posix-socket :pf-inet :sock-stream 0)))
  
negative.code: 
  (defgeneric protocol (posix-socket)
    (:documentation "Return the protocol used by the POSIX-SOCKET."))
  
  (defgeneric socket (object)
    (:documentation "Return the POSIX-SOCKET object used by OBJECT."))
  
  (defclass posix-socket ()
    ((namespace
  