class CI_Session userdata([$key = NULL])

unset_userdata($key)

has_userdata($key)

unmark_flash($key)

sess_regenerate([$destroy = FALSE])

userdata([$key = NULL])

set_flashdata($data[, $value = NULL])

keep_flashdata($key)

mark_as_temp($key[, $ttl = 300])

get_temp_keys()