(PHP 5)
DirectoryIterator::isWritable — Determine if current DirectoryIterator item can be written to
Determines if the current DirectoryIterator item is writable.
This function has no parameters.
   Returns TRUE if the file/directory is writable, otherwise FALSE
  
Example #1 DirectoryIterator::isWritable() example
This example lists the files and directories which can be opened for writing in the directory containing the script.
<?php
$iterator = new DirectoryIterator(dirname(__FILE__));
foreach ($iterator as $fileinfo) {
    if ($fileinfo->isWritable()) {
        echo $fileinfo->getFilename() . "\n";
    }
}
?>
The above example will output something similar to:
apples.txt bananas.html pears