diff --git a/src/move.c b/src/move.c
index aea9ae7e1..d1088b2b1 100644
--- a/src/move.c
+++ b/src/move.c
@@ -2462,7 +2462,7 @@ void move_units(void)
     }
 }
 
-void move_ships() {
+void move_ships(void) {
     region* r = regions;
     while (r != NULL) {
         unit** up = &r->units;