php clear session

1session_destroy(); // To delete whole session
2// OR
3unset($_SESSION['myVar']); // To delete a session var

1<?php 
2 session_start(); // start session
3 session_destroy();  // Delete whole session
4// OR
5unset($_SESSION['username']); // delete any specific session only
6?>

1<?php
2   unset($_SESSION['counter']);
3?>

1session_unset();    //Destrol all session variables

1<?php
2// Destroy the currently active session.
3session_destroy();
4?>

1<?php
2session_destroy();
3?>
4
5