title: Unblocking accept()
body: <p>I have a blocking call to accept(). From another thread I close the socket, hoping that it'll unblock the accept() call, which it does but I have a case when it doesn't: e.g. thread A enters accept(), thread B closes the socket, thread A doesn't return from accept().</p>
  
  <p>Question: what could cause closing a socket to not unblock an accept()?</p>