diff --git a/ospf6d/ospf6d.h b/ospf6d/ospf6d.h
index 13699d6..0c86386 100644
--- a/ospf6d/ospf6d.h
+++ b/ospf6d/ospf6d.h
@@ -101,6 +101,17 @@
       zlog_warn ("strftime error");                       \
   } while (0)
 
+#define threadtimer_string(now, t, buf, size)                         \
+  do {                                                                \
+    struct timeval result;                                            \
+    if (!t)                                                           \
+      snprintf(buf, size, "inactive");				      \
+    else {                                                            \
+      timersub(&t->u.sands, &now, &result);                           \
+      timerstring(&result, buf, size);                                \
+    }                                                                 \
+} while (0)
+
 /* for commands */
 #define OSPF6_AREA_STR      "Area information\n"
 #define OSPF6_AREA_ID_STR   "Area ID (as an IPv4 notation)\n"