diff --git a/poll/poll_bsd.go b/poll/poll_bsd.go
index 918f416..d804ab9 100644
--- a/poll/poll_bsd.go
+++ b/poll/poll_bsd.go
@@ -26,7 +26,7 @@ func New(fd int) (p *Poller, err error) {
 		Flags:  syscall.EV_ADD | syscall.EV_ENABLE | syscall.EV_ONESHOT,
 		Fflags: 0,
 		Data:   0,
-		Udata:  nil,
+		Udata:  0,
 	}
 	return p, nil
 }