Struct TimerFd

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

A safe wrapper around a Linux timerfd.

Implementations

impl TimerFd

pub fn new() -> Result<TimerFd>

Create a new TimerFd.

This creates a nonsettable monotonically increasing clock that does not change after system startup. The timer is initally disarmed and must be armed by calling reset.

pub fn reset(&mut self, dur: Duration, interval: Option<Duration>) -> Result<()>

Arm the TimerFd.

Set the timer to expire after dur.

Arguments

• dur: Specify the initial expiration of the timer.
• interval: Specify the period for repeated expirations, depending on the value passed. If interval is not None, it represents the period after the initial expiration. Otherwise the timer will expire just once. Cancels any existing duration and repeating interval.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::timerfd::TimerFd;

let mut timer = TimerFd::new().unwrap();
let dur = Duration::from_millis(100);
let interval = Duration::from_millis(100);

timer.reset(dur, Some(interval)).unwrap();

pub fn wait(&mut self) -> Result<u64>

Wait until the timer expires.

The return value represents the number of times the timer has expired since the last time wait was called. If the timer has not yet expired once, this call will block until it does.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::timerfd::TimerFd;

let mut timer = TimerFd::new().unwrap();
let dur = Duration::from_millis(100);
let interval = Duration::from_millis(100);
timer.reset(dur, Some(interval)).unwrap();

sleep(dur * 3);
let count = timer.wait().unwrap();
assert!(count >= 3);

pub fn is_armed(&self) -> Result<bool>

Tell if the timer is armed.

Returns Ok(true) if the timer is currently armed, otherwise the errno set by timerfd_gettime.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::timerfd::TimerFd;

let mut timer = TimerFd::new().unwrap();
let dur = Duration::from_millis(100);

timer.reset(dur, None).unwrap();
assert!(timer.is_armed().unwrap());

pub fn clear(&mut self) -> Result<()>

Disarm the timer.

Set zero to disarm the timer, referring to timerfd_settime.

Examples

extern crate vmm_sys_util;
use vmm_sys_util::timerfd::TimerFd;

let mut timer = TimerFd::new().unwrap();
let dur = Duration::from_millis(100);

timer.reset(dur, None).unwrap();
timer.clear().unwrap();

Trait Implementations

impl AsRawFd for TimerFd

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for TimerFd

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromRawFd for TimerFd

unsafe fn from_raw_fd(fd: RawFd) -> Self

This function is unsafe as the primitives currently returned have the contract that they are the sole owner of the file descriptor they are wrapping. Usage of this function could accidentally allow violating this contract which can cause memory unsafety in code that relies on it being true.

impl IntoRawFd for TimerFd

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.