全局变量codeignator php

Question

我已经在codeignator公共变量中声明了

一个函数用于初始化，另一个用于修改 购买我无法修改功能

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Varan_search extends CI_Controller {

    /**
     * Index Page for this controller.
     *
     * Maps to the following URL
     *      http://example.com/index.php/welcome
     *  - or -
     *      http://example.com/index.php/welcome/index
     *  - or -
     * Since this controller is set as the default controller in
     * config/routes.php, it's displayed at http://example.com/
     *
     * So any other public methods not prefixed with an underscore will
     * map to /index.php/welcome/<method_name>
     * @see https://codeigniter.com/user_guide/general/urls.html
     */

  protected  $searchdata = array();
  protected  $j,$i;



    function __construct() 
    {
        parent::__construct();

        $this->load->database();
        $this->load->model("Functions");
        $this->load->library('session');
        //echo $this->session->has_userdata('staff_id');

        if(isset($_SESSION["staff_id"]) and $_SESSION["staff_id"] == "")
        {
            header("location:".$this->config->item("base_url")."index.php/dashboard/");
        }