Problem: code duplication around getsockname

Solution: also use get_socket_address from base class

src/ipc_listener.cpp

@@ -153,15 +153,10 @@ void zmq::ipc_listener_t::in_event ()
 int zmq::ipc_listener_t::get_address (std::string &addr_)
 {
     struct sockaddr_storage ss;
-#ifdef ZMQ_HAVE_HPUX
-    int sl = sizeof (ss);
-#else
-    socklen_t sl = sizeof (ss);
-#endif
-    int rc = getsockname (_s, reinterpret_cast<sockaddr *> (&ss), &sl);
-    if (rc != 0) {
+    const zmq_socklen_t sl = get_socket_address (&ss);
+    if (sl == 0) {
         addr_.clear ();
-        return rc;
+        return -1;
     }
 
     ipc_address_t addr (reinterpret_cast<struct sockaddr *> (&ss), sl);