They are some pre-defined system filter
attached to aio requests
attached to vnodes
attached to struct proc
The EV_SET() macro is provided for ease of initializing a kevent structure.
It is an action.. add event to kq (implies enable).
It is an action.. delete event from kq
It is an action.. enable event.
It is an action.. disable event (not reported)
flags supported. only report one occurrence.
flags supported. clear event state after reporting .
flags supported. reserved by system.
flags supported. filter-specific flag.
returned value.EOF detected.
returned value. error, data contains errno.