title: Can connect() return 0 with non-blocking socket?
body: <p>For a non-blocking net socket, can <code>connect()</code> return 0?</p>
  
  <p>The <em>man</em> page just says
  it will return -1 and set errno to EINPROGRESS if "The socket is non-blocking and the connection cannot  be  completed  immediately".</p>
  
  <p>What does "immediately" exactly mean?</p>
  
  <p>If <code>connect()</code> CAN return 0 in this case, then under what situation it will return 0 which stands for success? When network between client and server is very good? Or?</p>