PHP uses session_destroy() to delete Session data

  session_start () ;
  session_register ( "A" ) ;
  session_register ( "B" ) ;
  session_register ( "C" ) ;

  $A = "AAA";
  $B = "BBB";
  $C = "CCC";

  $result = session_destroy () ;
  if ($result=1) {
     echo "The session is destroyed! " , "n " ;
  } else {
     echo "The session could not be destroyed. " , " n" ;
  }

  echo $pop;
?>