Session question -- $HTTP_SESSION_VARS scope

I'm writing a progam that uploads a file using post. The script that processes the upload sets a session var. $HTTP_SESSION_VARS['message'].
At the end of the script that process the post I do this:

header('Location:'.'index.php';

The session variable is in scope in index.php. However, if I call a function from index, the session variable is notset? I thought it was global?

See the example script below. message is displayed, message2 is empty.

Thanks.


<?php

function display_message ($message)
{
$message2 = $HTTP_SESSION_VARS['message'];
echo $message;
echo $message2;
}

session_start();

//PROCESS A FORM HERE, AND USE ANOTHER FILE
//TO PROCESS THE UPLOAD. and sets the session variable
//$HTTP_SESSION_VARS['message'] = 'processed in form'

$message = $HTTP_SESSION_VARS['message'];

display_message ($message);

?>

Maybe registering the variable would help. In any case, it's probably better practice to pass the variable to your function than to rely on the global.

and using the session_start() at the very beggining of the script. BEFORE the $_SESSION is set would properly help. Because the $_SESSION cant be used outside the session_start()... !!

I figured out what I was doing wrong. Turns out that the psuedocode above does isn't exactly how my script worked.

My problem was that I was using: $HTTP_SEESSION_VARS['message'], and another variable called $message. Since I have 'register globals' enabled, these two globals are referencing the same variable.

From now on I'll prefix all references to global arrays with a prefix: $HTTP_SEESSION_VARS['session_message']

Thanks.