Specifying content type for AMFPHP in cURL

I am using libcurl to create an http connection to an amfphp server. Do I have to set the content type to any specific format? I noticed there is a option called AMFPHP_CONTENT_TYPE in PHP cURL but I couldn't find a correspond开发者_如何学运维ing value in C.

Found it. I have to add Content-type: application/x-amf to the POST header.