diff --git a/iflytop_xsync_protocol.h b/iflytop_xsync_protocol.h
index e9518cd..3eb8bb5 100644
--- a/iflytop_xsync_protocol.h
+++ b/iflytop_xsync_protocol.h
@@ -52,8 +52,32 @@ typedef enum {
   kxs_ec_send_fail                  = 4,
   kxs_ec_receive_fail               = 5,
   kxs_ec_setsockopt_rx_timeout_fail = 6,
+  kxs_ec_lose_connect               = 7,
 } xs_error_code_t;
 
+static inline const char* xs_error_code_2_str(xs_error_code_t ecode) {
+  switch (ecode) {
+    case kxs_ec_success:
+      return "success";
+    case kxs_ec_overtime:
+      return "overtime";
+    case kxs_ec_socket_fail:
+      return "socket fail";
+    case kxs_ec_bind_fail:
+      return "bind fail";
+    case kxs_ec_send_fail:
+      return "send fail";
+    case kxs_ec_receive_fail:
+      return "receive fail";
+    case kxs_ec_setsockopt_rx_timeout_fail:
+      return "setsockopt rx timeout fail";
+    case kxs_ec_lose_connect:
+      return "lose connect";
+    default:
+      return "unknown error";
+  }
+}
+
 #pragma pack(1)
 
 typedef struct {