title: can I register 2 or multiple events for the same socket descriptor on epoll?
body: <p>for the same socket, I want to register two events: one is EPOLLIN and another is EPOLLOUT|EPOLLET.</p>
  
  <p>so for input, I want it to be level trigger and for output I want it to be edge trigger.</p>
  
  <pre><code>            ev.data.fd=fd;
              ev.events=EPOLLIN;
              epoll_ctl(epfd,EPOLL_CTL_ADD,fd,&amp;ev);
              ev.events=EPOLLOUT|EPOLLET;
              epoll_ctl(epfd,EPOLL_CTL_ADD,fd,&amp;ev);
  </code></pre>
  
  <p>is it possible or not? are there any problems? thanks!</p>