How should I call this function? I'm new to PHP. Here's my code... but I have an error
Notice: Undefined variable: ip in C:\xampp\htdocs\PHPTest\ip.php on line 19
    <?php
    function getRealIpAddr(){
        if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
        {
          $ip=$_SERVER['HTTP_CLIENT_IP'];
        }
        elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
        {
          $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
        }
        else
        {
          $ip=$_SERVER['REMOTE_ADDR'];
        }
        return $ip;
    }
    call_user_func('getRealIpAddr', '$ip');
    echo $ip;
    ?>
UPDATE
Strange reason, I'm using Windows 10, localhost, xampp and google Chrome this script doesn't provide me an ip address! That's why a corrected code was empty... Thought it was some kind of errors or something
Second UPDATE
If you're getting no ip like me, you may try this solution on httpd.conf
 
     
     
     
    