Session destroy problem

[eluser]gayathri[/eluser]
Hi all,

I am trying to destroy the session by using this $this->session->sess_destroy(); command, but its not destrying properly, if i use if condition, it shows failure only, so please let me know, what is wrong in this.

function logout()
{
$logout=$this->session->sess_destroy();
if(isset($logout))
{
redirect('login');
}
else
{
echo "not destroyed";
}
}