为什么session_start（）函数在php构造函数中不起作用？

Question

This is my below code

first.php

class Session
{
   function __construct()
   {
      session_start();
   }
   function start()
   {
      $_SESSION['id'] = "1";
   }
}

second.php

 require "first.php";
 $session = new Session();
 $session->start();
 echo "Session Id ".$_SESSION['id'];

It gives me an error that _SESSION not defined So i have to define session_start in start function and then it worked but i want to use it in constructor!!

Answer 1

I have tried your code on my PC (Ubuntu 16.4) and its working fine.