diff --git a/src/trackfds.h b/src/trackfds.h
index 378c327..446639f 100644
--- a/src/trackfds.h
+++ b/src/trackfds.h
@@ -117,7 +117,7 @@ static void update_environment(void) {
 
 
 #ifdef DEBUG
-static void tracked_fds_debug() {
+static void tracked_fds_debug(void) {
     debug("tracked_fds: %d/%d\n", tracked_fds_count, tracked_fds_space);
     size_t i;
     for (i = 0; i < tracked_fds_count; i++) {