Ftp library on c++ with uploading over HTTP proxy

Is anybody knows the free library for uploading over proxy with Http authentication? Maybe some url on samples how it could be.

From stackoverflow

• You can use libcurl. You can see a FTP upload sample here.

  For adding http proxy authentication, you will need to use options CURLOPT_PROXY, CURLOPT_PROXYPORT, CURLOPT_PROXYTYPE, CURLOPT_PROXYUSERPWD and CURLOPT_PROXYUSERNAME with curl_easy_setopt.

  I might be missing something since I can't test it right now, but you can see the documentation in detail here.

• Thanks. I'l try it.