I am running into a sporadic problem with curl's RETURNTRANSFER option. I am not sure if I have overlooked something in my code that is causing it, or if it is just not well documented and I am unaware of the RETURNTRANSFER workings.I am using curl (via php) to send xml data via POST to an external listener. If successful, the listener responds and returns the same xml, with one or two fields populated that I sent through empty.eg. \[code\]<Status />\[/code\] becomes \[code\]<Status>\[/code\]Accepted\[code\]</Status>\[/code\]. A rough size of the full xml POST - [upload_content_length] => 1414. A unique ID (generated on my side) is sent, if the listener receives a duplicate ID, it declines the xml data and responds with a plain text error message. This works 99.9% of the time.The curl code is :\[code\]$header[] = "Content-Type: text/xml";$header[] = "Content-length: ".strlen($post_string);$x = curl_init("https://xyz.com");curl_setopt($x, CURLOPT_HEADER, 0);curl_setopt($x, CURLOPT_HTTPHEADER, $header);curl_setopt($x, CURLOPT_POST, 1);curl_setopt($x, CURLOPT_POSTFIELDS,$xmldata);curl_setopt($x, CURLOPT_FOLLOWLOCATION, 1);curl_setopt($x, CURLOPT_REFERER, "https://mypage.com");curl_setopt($x, CURLOPT_RETURNTRANSFER, 1);curl_setopt($x, CURLOPT_PORT, 443);curl_setopt($x, CURLOPT_SSL_VERIFYPEER, 0); //to allow self-signed SSL certcurl_setopt($x, CURLOPT_SSL_VERIFYHOST, 0); //to allow self-signed SSL certcurl_setopt($x, CURLOPT_TIMEOUT, 30);curl_setopt($x, CURLOPT_FORBID_REUSE, TRUE);curl_setopt($x, CURLOPT_FRESH_CONNECT, TRUE);curl_setopt($x, CURLOPT_BUFFERSIZE, 64000);curl_setopt($x, CURLOPT_VERBOSE, 1);$listenerresponse = curl_exec($x);$info = curl_getinfo($x);curl_close($x); \[/code\]Recently I have been picking up errors where the listener errors on duplicate IDs.My logs show the timeline as this ::[*]curl POST of unique id "12345678"[*]listener responds "Duplicate ID" at 2010-10-13 17:27:59[*]listener responds "Accepted" 2010-10-13 17:28:06Initially I though a previous ID had been cached somehow and was being sent erroneously, but this is not the case. The listener receives the correct ID. The listener logs show it the other way around, with a slightly differing chronology:[*]Listener responds "Accepted" at 2010-10-13 17:27:48[*]Listener responds "Duplicate ID" at 2010-10-13 17:27:58From my understanding, I would expect the curl thread to wait for the response, and not send another request. Am I right in presuming that the problem is network related - possible packets dropping/something similar?Any suggestions on how to prevent this happening would be most appreciated.Ideally I would like curl to send and wait for the full response before sending off another request... Is there an option to specify this? Please help 
Thank you for your attention.S.
Thank you for your attention.S.