Is the readfile function supported?

The readfile function is available.

However readfile($file); will try to read the file in order to stock it in the RAM in its entirety before sending it to the visitor - this is unnecessary and risky depending on the size of the file. Here's what to do instead:

$handle = fopen($file, "rb");
if ($handle) {
 while (!feof($handle)) {
 print fread($handle, 65536);
 }
 fclose($handle);
}