diff --git a/cg.go b/cg.go
index 36dc2f4..715eceb 100644
--- a/cg.go
+++ b/cg.go
@@ -221,7 +221,7 @@ func (cg Cgroup) GetUIDGID() (tasksUID UID, tasksGID GID, controlUID UID, contro
 
 }
 
-func (cg Cgroup) AttachTaskPid(pid Int) {
+func (cg Cgroup) AttachTaskPid(pid int) error {
 	return _err(C.cgroup_attach_task_pid(cg.g, pid))
 }