diff --git a/libmapper/mapper.c b/libmapper/mapper.c
index 962b4e0..194041e 100644
--- a/libmapper/mapper.c
+++ b/libmapper/mapper.c
@@ -61,6 +61,10 @@
 	int retry;
 };
 
+struct mapper_async_subtree
+{
+};
+
 static int async_wait_match_introspection_complete(sd_bus_message *, void *,
 		sd_bus_error *);
 static int async_wait_check_done(mapper_async_wait *);
@@ -374,6 +378,20 @@
 	return r;
 }
 
+int mapper_subtree_async(sd_bus *conn,
+		sd_event *loop,
+		char *namespace,
+		char *interface,
+		void (*callback)(int, void *),
+		void *userdata,
+		mapper_async_subtree **t,
+		int op)
+{
+	int r = 0;
+
+	return r;
+}
+
 int mapper_get_object(sd_bus *conn, const char *obj, sd_bus_message **reply)
 {
 	sd_bus_error error = SD_BUS_ERROR_NULL;