1.8.0[−][src]Struct std::time::Instant
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.
Example:
use std::time::{Duration, Instant}; use std::thread::sleep; fn main() { let now = Instant::now(); // we sleep for 2 seconds sleep(Duration::new(2, 0)); // it prints '2' println!("{}", now.elapsed().as_secs()); }Run
Methods
impl Instant
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pub fn now() -> Instant
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Returns an instant corresponding to "now".
Examples
use std::time::Instant; let now = Instant::now();Run
pub fn duration_since(&self, earlier: Instant) -> Duration
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Returns the amount of time elapsed from another instant to this one.
Panics
This function will panic if earlier
is later than self
.
Examples
use std::time::{Duration, Instant}; use std::thread::sleep; let now = Instant::now(); sleep(Duration::new(1, 0)); let new_now = Instant::now(); println!("{:?}", new_now.duration_since(now));Run
pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration>
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Returns the amount of time elapsed from another instant to this one, or None if that instant is earlier than this one.
Examples
#![feature(checked_duration_since)] use std::time::{Duration, Instant}; use std::thread::sleep; let now = Instant::now(); sleep(Duration::new(1, 0)); let new_now = Instant::now(); println!("{:?}", new_now.checked_duration_since(now)); println!("{:?}", now.checked_duration_since(new_now)); // NoneRun
pub fn saturating_duration_since(&self, earlier: Instant) -> Duration
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Returns the amount of time elapsed from another instant to this one, or zero duration if that instant is earlier than this one.
Examples
#![feature(checked_duration_since)] use std::time::{Duration, Instant}; use std::thread::sleep; let now = Instant::now(); sleep(Duration::new(1, 0)); let new_now = Instant::now(); println!("{:?}", new_now.saturating_duration_since(now)); println!("{:?}", now.saturating_duration_since(new_now)); // 0nsRun
pub fn elapsed(&self) -> Duration
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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 std::thread::sleep; use std::time::{Duration, Instant}; let instant = Instant::now(); let three_secs = Duration::from_secs(3); sleep(three_secs); assert!(instant.elapsed() >= three_secs);Run
pub fn checked_add(&self, duration: Duration) -> Option<Instant>
1.34.0[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>
1.34.0[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 PartialEq<Instant> for Instant
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impl Eq for Instant
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impl Ord for Instant
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fn cmp(&self, other: &Instant) -> Ordering
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fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
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Restrict a value to a certain interval. Read more
impl PartialOrd<Instant> for Instant
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fn partial_cmp(&self, other: &Instant) -> Option<Ordering>
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fn lt(&self, other: &Instant) -> bool
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fn le(&self, other: &Instant) -> bool
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fn gt(&self, other: &Instant) -> bool
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fn ge(&self, other: &Instant) -> bool
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impl Hash for Instant
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fn hash<__H: Hasher>(&self, state: &mut __H)
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fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl Copy for Instant
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impl Debug for Instant
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impl Sub<Duration> for Instant
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type Output = Instant
The resulting type after applying the -
operator.
fn sub(self, other: Duration) -> Instant
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impl Sub<Instant> for Instant
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type Output = Duration
The resulting type after applying the -
operator.
fn sub(self, other: Instant) -> Duration
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impl Add<Duration> for Instant
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type Output = Instant
The resulting type after applying the +
operator.
fn add(self, other: Duration) -> Instant
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Panics
This function may panic if the resulting point in time cannot be represented by the
underlying data structure. See checked_add
for a version without panic.
impl AddAssign<Duration> for Instant
1.9.0[src]
fn add_assign(&mut self, other: Duration)
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impl SubAssign<Duration> for Instant
1.9.0[src]
fn sub_assign(&mut self, other: Duration)
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impl Clone for Instant
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Auto Trait Implementations
Blanket Implementations
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,