[Resolved] force download / large files

[freebie]

I want to do a binary read on files to force download of the files, and I was wondering if it's possible to do this without having to read the entire file into memory. So for instance, the following code I would assume would read the entire contents into memory

$handle = fopen($filename, "rb");
$contents = fread($handle, filesize($filename));

Is there a way around this?
At first, I thought doing a partial read in a loop might get around this (such as this)

while (!feof($handle)) {
  echo fread($handle, 8192);
}

but then I thought it's still probably keeping it all in memory until the end of the script at which point it's output.

Maybe this would work?

while (!feof($handle)) {
  echo fread($handle, 8192);
  ob_flush();
}

Does anyone have any thoughts on this (to prevent 20 MB of memory from being consumed each time a 20MB file is downloaded)?

Thanks for any suggestions.

[freebie]

just posting my results.
the ob_flush() did seem to need to be used (without it I was getting page cannot be displayed).

here's the complete download script. Note, my memory_limit is set to 8M, but I can download 20MB files using this script.

<?php
session_cache_limiter("public");
session_start();
ob_start();
include('../../../includes/login_check.php');
include('../../../includes/common.php');
$FName=mysql_result(mysql_query("select FName from UploadTemp where ID=".$_GET['uf_bb']." AND Ticket=".$_GET['uf_tt']),0);
if(file_exists("/var/www/www/uploads/".$_SESSION['bta']."/".$FName)){
	if(strstr($_SERVER["HTTP_USER_AGENT"],"MSIE 5.5")) { 
		 $att = "";
	}else{
  		 $att = " attachment;"; 
	}
	header("Content-Type: text/html; name=\"$FName\""); 
	header("Content-Disposition:".$att." filename=\"$FName\"");
	header('Content-Transfer-Encoding: binary'); 
	$handle = fopen("/var/www/www/uploads/".$_SESSION['bta']."/".$FName, "rb");
	while (!feof($handle)) {
 		 echo fread($handle, 8192);
		 ob_flush();
	}
	fclose($handle);
}else{
  // can display error here
}
?>