when opendir() using it close with closedir() in php

closedir.php :

<?php

//Open send directory
if(@$dir = opendir("send"))
{
echo '<br>dir opened<br>';

//List files in send directory
while (($file = readdir($dir)) !== false)
{
echo "filename: " . $file . "<br />";
}
closedir($dir);
echo '<br>dir closed<br>';
}
else
echo 'directory not opened';
?>
=========================================
outputs :
 1)
directory not opened

2)
dir opened
filename: .
filename: ..
filename: sendsms.html
filename: sendsms.php
filename: send_vard.php
filename: send_vcard_sms.html
filename: smser.php

dir closed