Struct tokio::time::Instant[][src]

pub struct Instant { /* fields omitted */ }

A measurement of a monotonically nondecreasing clock. Opaque and useful only with Duration.

Instants are always guaranteed to be no less than any previously measured instant when created, and are often useful for tasks such as measuring benchmarks or timing how long an operation takes.

Note, however, that instants are not guaranteed to be steady. In other words, each tick of the underlying clock may not be the same length (e.g. some seconds may be longer than others). An instant may jump forwards or experience time dilation (slow down or speed up), but it will never go backwards.

Instants are opaque types that can only be compared to one another. There is no method to get “the number of seconds” from an instant. Instead, it only allows measuring the duration between two instants (or comparing two instants).

The size of an Instant struct may vary depending on the target operating system.

Note

This type wraps the inner std variant and is used to align the Tokio clock for uses of now(). This can be useful for testing where you can take advantage of time::pause() and time::advance().

Implementations

impl Instant[src]

pub fn now() -> Instant[src]

Returns an instant corresponding to “now”.

Examples

use tokio::time::Instant;

let now = Instant::now();

pub fn from_std(std: Instant) -> Instant[src]

Create a tokio::time::Instant from a std::time::Instant.

pub fn into_std(self) -> Instant[src]

Convert the value into a std::time::Instant.

pub fn duration_since(&self, earlier: Instant) -> Duration[src]

Returns the amount of time elapsed from another instant to this one.

Panics

This function will panic if earlier is later than self.

pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration>[src]

Returns the amount of time elapsed from another instant to this one, or None if that instant is later than this one.

Examples

use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let now = Instant::now();
    sleep(Duration::new(1, 0)).await;
    let new_now = Instant::now();
    println!("{:?}", new_now.checked_duration_since(now));
    println!("{:?}", now.checked_duration_since(new_now)); // None
}

pub fn saturating_duration_since(&self, earlier: Instant) -> Duration[src]

Returns the amount of time elapsed from another instant to this one, or zero duration if that instant is earlier than this one.

Examples

use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let now = Instant::now();
    sleep(Duration::new(1, 0)).await;
    let new_now = Instant::now();
    println!("{:?}", new_now.saturating_duration_since(now));
    println!("{:?}", now.saturating_duration_since(new_now)); // 0ns
}

pub fn elapsed(&self) -> Duration[src]

Returns the amount of time elapsed since this instant was created.

Panics

This function may panic if the current time is earlier than this instant, which is something that can happen if an Instant is produced synthetically.

Examples

use tokio::time::{Duration, Instant, sleep};

#[tokio::main]
async fn main() {
    let instant = Instant::now();
    let three_secs = Duration::from_secs(3);
    sleep(three_secs).await;
    assert!(instant.elapsed() >= three_secs);
}

pub fn checked_add(&self, duration: Duration) -> Option<Instant>[src]

Returns Some(t) where t is the time self + duration if t can be represented as Instant (which means it’s inside the bounds of the underlying data structure), None otherwise.

pub fn checked_sub(&self, duration: Duration) -> Option<Instant>[src]

Returns Some(t) where t is the time self - duration if t can be represented as Instant (which means it’s inside the bounds of the underlying data structure), None otherwise.

Trait Implementations

impl Add<Duration> for Instant[src]

type Output = Instant

The resulting type after applying the + operator.

impl AddAssign<Duration> for Instant[src]

impl Clone for Instant[src]

impl Copy for Instant[src]

impl Debug for Instant[src]

impl Eq for Instant[src]

impl From<Instant> for Instant[src]

impl From<Instant> for Instant[src]

impl Hash for Instant[src]

impl Ord for Instant[src]

impl PartialEq<Instant> for Instant[src]

impl PartialOrd<Instant> for Instant[src]

impl StructuralEq for Instant[src]

impl StructuralPartialEq for Instant[src]

impl Sub<Duration> for Instant[src]

type Output = Instant

The resulting type after applying the - operator.

impl Sub<Instant> for Instant[src]

type Output = Duration

The resulting type after applying the - operator.

impl SubAssign<Duration> for Instant[src]

Auto Trait Implementations

impl RefUnwindSafe for Instant

impl Send for Instant

impl Sync for Instant

impl Unpin for Instant

impl UnwindSafe for Instant

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.