EV_NONE = 0x00, /* no events */
EV_READ = 0x01, /* ev_io detected read will not block */
EV_WRITE = 0x02, /* ev_io detected write will not block */
+ EV_EXCEPTION= 0x04, /* ev_io detected exceptional condition */
EV__IOFDSET = 0x80, /* internal use only */
EV_IO = EV_READ, /* alias for type-detection */
EV_TIMER = 0x00000100, /* timer timed out */