ctype_cntrl

<?

$text = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x7f\t\n\v\f\r\e";

$return = ctype_cntrl($text);

var_export($return);

?>

true

<?

for ($i = 0; $i <= 255; ++$i)
{
    $return = ctype_cntrl($i);

    if ($return)
    {
        $character = chr($i);

        echo "$i: $character\n";
    }
}

?>

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