(PHP 5)
stream_get_filters — Retrieve list of registered filters
Retrieve the list of registered filters on the running system.
Returns an indexed array containing the name of all stream filters available.
Example #1 Using stream_get_filters() 以上例程的输出类似于：
<?php
$streamlist = stream_get_filters();
print_r($streamlist);
?>
Array (
[0] => string.rot13
[1] => string.toupper
[2] => string.tolower
[3] => string.base64
[4] => string.quoted-printable
)