diff --git a/pl/corout.yap b/pl/corout.yap
index c6cf548b4..1edb31160 100644
--- a/pl/corout.yap
+++ b/pl/corout.yap
@@ -26,9 +26,9 @@
  * 
 */
 
+:-  op(1150, fx, prolog:block).
 
 :- module('$coroutining',[
-			  op(1150, fx, block)
 				%dif/2,
 				%when/2,
 				%block/1,