title: cURL -- cookies and sessions
body: <p>I would like to understand the four options of cURL for cookies:</p>
  
  <pre><code>CURLOPT_COOKIESESSION  
  CURLOPT_COOKIEFILE
  CURLOPT_COOKIEJAR
  CURLOPT_COOKIE
  </code></pre>
  
  <p>I understand that <code>COOKIEJAR</code> is meant for writing cookies, and <code>COOKIEFILE</code> is meant for reading. 
  So what is <code>COOKIESESSION</code> for ? 
  The <code>CURLOPT_COOKIE</code> is custom, but can I use it to maintain a session with the server ?</p>