// create a client instance.
pc_client_t *client = pc_client_new();
  

  // add some event callback.
  pc_add_listener(client, "onHey", on_hey);
  pc_add_listener(client, PC_EVENT_DISCONNECT, on_close);

// disconnect event callback.
void on_close(pc_client_t *client, const char *event, void *data) {
  printf("client closed: %d.\n", client->state);
}

  struct sockaddr_in address;

  memset(&address, 0, sizeof(struct sockaddr_in));
  address.sin_family = AF_INET;
  address.sin_port = htons(port);
  address.sin_addr.s_addr = inet_addr(ip);

  // try to connect to server.
  if(pc_client_connect(client, &address)) {
    printf("fail to connect server.\n");
    pc_client_destroy(client);
    return 1;
  }

// notified callback
void on_notified(pc_notify_t *req, int status) {
 if(status == -1) {
   printf("Fail to send notify to server.\n");
 } else {
   printf("Notify finished.\n");
 }

 // release resources
 json_t *msg = req->msg;
 json_decref(msg);
 pc_notify_destroy(req);
}

// send a notify
void do_notify(pc_client_t *client) {
 // compose notify.
 const char *route = "connector.helloHandler.hello";
 json_t *msg = json_object();
 json_t *json_str = json_string("hello");
 json_object_set(msg, "msg", json_str);
 // decref json string
 json_decref(json_str);

 pc_notify_t *notify = pc_notify_new();
 pc_notify(client, notify, route, msg, on_notified);
}

// request callback
void on_request_cb(pc_request_t *req, int status, json_t *resp) {
 if(status == -1) {
   printf("Fail to send request to server.\n");
 } else if(status == 0) {
   char *json_str = json_dumps(resp, 0);
   if(json_str != NULL) {
     printf("server response: %s\n", json_str);
     free(json_str);
   }
 }

 // release relative resource with pc_request_t
 json_t *msg = req->msg;
 pc_client_t *client = req->client;
 json_decref(msg);
 pc_request_destroy(req);

 // stop client
 pc_client_stop(client);
}

// send a request
void do_request(pc_client_t *client) {
 // compose request
 const char *route = "connector.helloHandler.hi";
 json_t *msg = json_object();
 json_t *str = json_string("hi~");
 json_object_set(msg, "msg", str);
 // decref for json object
 json_decref(str);

 pc_request_t *request = pc_request_new();
 pc_request(client, request, route, msg, on_request_cb);
}