Struct EventFdTrigger

pub struct EventFdTrigger(/* private fields */);

Newtype for implementing the trigger functionality for EventFd.

The trigger is used for handling events in the legacy devices.

Implementations

impl EventFdTrigger

pub fn try_clone(&self) -> Result<Self>

pub fn new(evt: EventFd) -> Self

pub fn get_event(&self) -> EventFd

Methods from Deref<Target = EventFd>

pub fn write(&self, v: u64) -> Result<(), Error>

Add a value to the eventfd’s counter.

When the addition causes the counter overflow, this would either block until a read is performed on the file descriptor, or fail with the error EAGAIN if the file descriptor has been made nonblocking.

Arguments

• v: the value to be added to the eventfd’s counter.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};

let evt = EventFd::new(EFD_NONBLOCK).unwrap();
evt.write(55).unwrap();

pub fn read(&self) -> Result<u64, Error>

Read a value from the eventfd.

If the counter is zero, this would either block until the counter becomes nonzero, or fail with the error EAGAIN if the file descriptor has been made nonblocking.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};

let evt = EventFd::new(EFD_NONBLOCK).unwrap();
evt.write(55).unwrap();
assert_eq!(evt.read().unwrap(), 55);

pub fn try_clone(&self) -> Result<EventFd, Error>

Clone this EventFd.

This internally creates a new file descriptor and it will share the same underlying count within the kernel.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::eventfd::{EventFd, EFD_NONBLOCK};

let evt = EventFd::new(EFD_NONBLOCK).unwrap();
let evt_clone = evt.try_clone().unwrap();
evt.write(923).unwrap();
assert_eq!(evt_clone.read().unwrap(), 923);

Trait Implementations

impl Deref for EventFdTrigger

type Target = EventFd

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Trigger for EventFdTrigger

type E = Error

Underlying type for the potential error conditions returned by Self::trigger.

fn trigger(&self) -> Result<()>

Trigger an event.