Use session cookies in Wordpress

functions.php

//Enable sessions i wordpress
if ( !session_id() )
add_action( 'init', 'session_start' );

inyourtheme.php

session_start();

if(isset($_SESSION['test']))
	{
	$_SESSION['test']='Hello again!';
	}
else
	{
	$_SESSION['test']='First time here';
	}
	
	echo $_SESSION['test'];