title: Will EAGAIN return on send for anything other than buffer full?
body: <p>If I use send() on a non-blocking tcp socket in Linux will it return EAGAIN for anything other than a send buffer full condition?</p>
  
  <p>I basically need to decide if I want to use the socket send buffer as the only buffer for my app or if I need my own user space buffer to feed the socket buffer.</p>