empty( session_id() ) doesn't work

Hi there, why do I have to use $session_id = session_id(); if( empty( $session_id ) ) { // session_start() was not called, yet } instead of if( empty( session_id() ) ) { // session_start() was not called, yet } which gives me a parser error. Is there another way to determine whether or not session_start() has already been called? Does it have side-effects when session_start() is called more than once? -- <?php $a=explode(" " ,"119 130 128 129 45 110 123 124 129 117 114 127 45 ". "125 117 125 45 117 110 112 120 114 127");for($i=0;$i<sizeof($a);$i++)print chr($a[$i]-13); /* http://sb.phpOpenTracker.de | sb@phpOpenTracker.de */ ?>