std::time::Instant
Struct std::time::Instant
pub struct Instant(_);
A measurement of a monotonically increasing clock. Opaque and useful only with Duration.
Instants are always guaranteed to be greater 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).
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());
} Methods
impl Instant
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fn now() -> Instant
Returns an instant corresponding to "now".
Examples
use std::time::Instant; let now = Instant::now();
fn duration_since(&self, earlier: Instant) -> Duration
Returns the amount of time elapsed from another instant to this one.
Panics
This function will panic if earlier is later than self, which should only be possible if earlier was created after self. Because Instant is monotonic, the only time that this should happen should be a bug.
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)); fn elapsed(&self) -> Duration
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); Trait Implementations
impl Copy for Instant
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impl Clone for Instant
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fn clone(&self) -> Instant
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)1.0.0
Performs copy-assignment from source. Read more
impl PartialEq for Instant
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fn eq(&self, __arg_0: &Instant) -> bool
This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, __arg_0: &Instant) -> bool
This method tests for !=.
impl Eq for Instant
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impl PartialOrd for Instant
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fn partial_cmp(&self, __arg_0: &Instant) -> Option<Ordering>
This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, __arg_0: &Instant) -> bool
This method tests less than (for self and other) and is used by the < operator. Read more
fn le(&self, __arg_0: &Instant) -> bool
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
fn gt(&self, __arg_0: &Instant) -> bool
This method tests greater than (for self and other) and is used by the > operator. Read more
fn ge(&self, __arg_0: &Instant) -> bool
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl Ord for Instant
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fn cmp(&self, __arg_0: &Instant) -> Ordering
This method returns an Ordering between self and other. Read more
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
The method for the + operator
impl AddAssign<Duration> for Instant
1.9.0
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fn add_assign(&mut self, other: Duration)
The method for the += operator
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
The method for the - operator
impl SubAssign<Duration> for Instant
1.9.0
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fn sub_assign(&mut self, other: Duration)
The method for the -= operator
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
The method for the - operator
impl Debug for Instant
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fn fmt(&self, f: &mut Formatter) -> Result
Formats the value using the given formatter.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/time/struct.Instant.html
