diff --git a/src/core/ddsi/src/ddsi_udp.c b/src/core/ddsi/src/ddsi_udp.c
index 4fb17db..4b46999 100644
--- a/src/core/ddsi/src/ddsi_udp.c
+++ b/src/core/ddsi/src/ddsi_udp.c
@@ -147,7 +147,6 @@ static ssize_t ddsi_udp_conn_write (ddsi_tran_conn_t conn, const nn_locator_t *d
 #if DDSRT_MSGHDR_FLAGS
   msg.msg_flags = (int) flags;
 #else
-  msg.msg_flags = 0;
   DDSRT_UNUSED_ARG(flags);
 #endif
 #if MSG_NOSIGNAL && !LWIP_SOCKET