-const char *p_porigin_ts = "preciseOriginTimeStamp";
-const char *p_origin_ts = "originTimeStamp";
-const char *p_recv_ts = "receiveTimeStamp";
+static const char *p_porigin_ts = "preciseOriginTimeStamp";
+static const char *p_origin_ts = "originTimeStamp";
+static const char *p_recv_ts = "receiveTimeStamp";