pthread_mutex_init (&user_class_obj->entry.lock, /* attr = */ NULL);
user_class_obj->entry.user_class = user_class;
lu_copy_ident_to_match (&user_class_obj->entry.match, ident, group_by);
pthread_mutex_init (&user_class_obj->entry.lock, /* attr = */ NULL);
user_class_obj->entry.user_class = user_class;
lu_copy_ident_to_match (&user_class_obj->entry.match, ident, group_by);