These are the event bits that can be associated with a file descriptor:
| Bit | Input to epoll_ctl()? |
Returned by epoll_wait()? |
Description |
| EPOLLIN | Yes | Yes | Data other than high-priority data can be read |
| EPOLLPRI | Yes | Yes | High-priority data can be read |
| EPOLLOUT | Yes | Yes | Normal data can be written |
| EPOLLET | Yes | n | Employ edge-triggered event notification |
| EPOLLONESHOT | Yes | n | Disable monitoring after one event notification |
| EPOLLERR | n | Yes | An error has occurred |
| EPOLLHUP | n | Yes | A hangup has occurred |
Many of these bits are analogous to bits used with poll().
(C) 2006, Michael Kerrisk