Cannot send session cache limiter - headers already sent

Question

I have been facing a problem with sessions which is becoming very annoying. Every time I try to start a session on a particular page I get the following error:

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at ............ on line 23


using this code:

<?php 
session_start(); 
if(isset($_SESSION['user'])) 
{ 

            $user = $_SESSION['user']; 
            echo "$user"; 
} 
else 
{
  } 
?>

Is it suggesting I've already used session_start(); ? I've had a look around but nothing really clears this up for me. Thank you in advance for the help!!

Answer 1

The line "Headers already sent" means that your PHP script already sent the HTTP headers, and as such it can't make modifications to them now. Check that you don't send ANY content before calling session_start. Better yet, just make session_start the first thing you do in your PHP file so put it at the absolute beginning, before all HTML basically.