diff --git a/inc/keyeventdefs.h b/inc/keyeventdefs.h
index b805988..eafd012 100644
--- a/inc/keyeventdefs.h
+++ b/inc/keyeventdefs.h
@@ -1,7 +1,7 @@
 #ifndef KEYEVENTDEFS_H
 #define KEYEVENTDEFS_H 1
 #include <sys/types.h>
-void process_io_events();
+void process_io_events(void);
 void kb_trans(u_short keycode, u_short upflg);
 void taking_mouse_down(void);
 void copy_cursor(int newx, int newy);