diff --git a/udp-listener.c b/udp-listener.c
index 3ea6ff5..7bfd96f 100644
--- a/udp-listener.c
+++ b/udp-listener.c
@@ -158,7 +158,9 @@ static void reap_timeouts(struct known_udp_source* sources, int n_src, fd_set* f
 }
 
 
-/* UDP listener: upon incoming packet, find where it should go */
+/* UDP listener: upon incoming packet, find where it should go
+ * This is run in its own process and never returns.
+ */
 void udp_listener(struct listen_endpoint* endpoint, int num_endpoints, int active_endpoint)
 {
     fd_set fds_r, fds_r_tmp;
diff --git a/udp-listener.h b/udp-listener.h
index 0c41d67..fc65a17 100644
--- a/udp-listener.h
+++ b/udp-listener.h
@@ -1,3 +1,5 @@
 
-/* UDP listener: upon incoming packet, find where it should go */
+/* UDP listener: upon incoming packet, find where it should go
+ * This is run in its own process and never returns.
+ */
 void udp_listener(struct listen_endpoint* endpoint, int num_endpoints, int active_endpoint);