diff --git a/reactos/include/psdk/objbase.h b/reactos/include/psdk/objbase.h
index da464214c1b..748d4eb61da 100644
--- a/reactos/include/psdk/objbase.h
+++ b/reactos/include/psdk/objbase.h
@@ -677,8 +677,9 @@ CoRegisterChannelHook(
 
 typedef enum tagCOWAIT_FLAGS
 {
-    COWAIT_WAITALL   = 0x00000001,
-    COWAIT_ALERTABLE = 0x00000002
+    COWAIT_WAITALL        = 0x00000001,
+    COWAIT_ALERTABLE      = 0x00000002,
+    COWAIT_INPUTAVAILABLE = 0x00000004
 } COWAIT_FLAGS;
 
 _Check_return_