Description:
------------
$ch = curl_ini("http://www.php.net/");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$page = curl_exec($ch);

Will echo the page out to the browser even though you specified not to do so with the non-zero RETURNTRANSFER value.

If you instead do:

$ch = curl_ini();
curl_setopt($ch, CURLOPT_URL, "http://www.php.net/");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$page = curl_exec($ch);


The problem goes away.