diff --git a/src/st/st-widget.c b/src/st/st-widget.c
index d93f1a49d..fedcd145e 100644
--- a/src/st/st-widget.c
+++ b/src/st/st-widget.c
@@ -2214,7 +2214,7 @@ st_set_slow_down_factor (gfloat factor)
  * Returns: the global factor applied to all animation durations
  */
 gfloat
-st_get_slow_down_factor ()
+st_get_slow_down_factor (void)
 {
   return st_slow_down_factor;
 }