diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 8c4c725b9df..eefc2571ee8 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -288,7 +288,7 @@ _winapi_Overlapped_cancel_impl(OverlappedObject *self)
 
     if (self->pending) {
         Py_BEGIN_ALLOW_THREADS
-        CancelIoEx(self->handle, &self->overlapped);
+        res = CancelIoEx(self->handle, &self->overlapped);
         Py_END_ALLOW_THREADS
     }