pub struct SystemTime(_);
A measurement of the system clock, useful for talking to external entities like the file system or other processes.
Distinct from the Instant type, this time measurement is not monotonic. This means that you can save a file to the file system, then save another file to the file system, and the second file has a SystemTime measurement earlier than the first. In other words, an operation that happens after another operation in real time may have an earlier SystemTime!
Consequently, comparing two SystemTime instances to learn about the duration between them returns a Result instead of an infallible Duration to indicate that this sort of time drift may happen and needs to be handled.
Although a SystemTime cannot be directly inspected, the UNIX_EPOCH constant is provided in this module as an anchor in time to learn information about a SystemTime. By calculating the duration from this fixed point in time, a SystemTime can be converted to a human-readable time, or perhaps some other string representation.
Example:
use std::time::{Duration, SystemTime};
use std::thread::sleep;
fn main() {
let now = SystemTime::now();
// we sleep for 2 seconds
sleep(Duration::new(2, 0));
match now.elapsed() {
Ok(elapsed) => {
// it prints '2'
println!("{}", elapsed.as_secs());
}
Err(e) => {
// an error occurred!
println!("Error: {:?}", e);
}
}
} impl SystemTime
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pub fn now() -> SystemTime
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Returns the system time corresponding to "now".
use std::time::SystemTime; let sys_time = SystemTime::now();
pub fn duration_since(
&self,
earlier: SystemTime
) -> Result<Duration, SystemTimeError>
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Returns the amount of time elapsed from an earlier point in time.
This function may fail because measurements taken earlier are not guaranteed to always be before later measurements (due to anomalies such as the system clock being adjusted either forwards or backwards).
If successful, Ok(Duration) is returned where the duration represents the amount of time elapsed from the specified measurement to this one.
Returns an Err if earlier is later than self, and the error contains how far from self the time is.
use std::time::SystemTime;
let sys_time = SystemTime::now();
let difference = sys_time.duration_since(sys_time)
.expect("SystemTime::duration_since failed");
println!("{:?}", difference); pub fn elapsed(&self) -> Result<Duration, SystemTimeError>
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Returns the amount of time elapsed since this system time was created.
This function may fail as the underlying system clock is susceptible to drift and updates (e.g. the system clock could go backwards), so this function may not always succeed. If successful, Ok(Duration) is returned where the duration represents the amount of time elapsed from this time measurement to the current time.
Returns an Err if self is later than the current system time, and the error contains how far from the current system time self is.
use std::thread::sleep;
use std::time::{Duration, SystemTime};
let sys_time = SystemTime::now();
let one_sec = Duration::from_secs(1);
sleep(one_sec);
assert!(sys_time.elapsed().unwrap() >= one_sec); impl Copy for SystemTime
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impl Clone for SystemTime
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fn clone(&self) -> SystemTime
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Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
impl PartialEq for SystemTime
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fn eq(&self, __arg_0: &SystemTime) -> bool
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This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, __arg_0: &SystemTime) -> bool
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This method tests for !=.
impl Eq for SystemTime
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impl PartialOrd for SystemTime
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fn partial_cmp(&self, __arg_0: &SystemTime) -> Option<Ordering>
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This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, __arg_0: &SystemTime) -> bool
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This method tests less than (for self and other) and is used by the < operator. Read more
fn le(&self, __arg_0: &SystemTime) -> bool
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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: &SystemTime) -> bool
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This method tests greater than (for self and other) and is used by the > operator. Read more
fn ge(&self, __arg_0: &SystemTime) -> bool
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This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl Ord for SystemTime
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fn cmp(&self, __arg_0: &SystemTime) -> Ordering
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This method returns an Ordering between self and other. Read more
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
impl Add<Duration> for SystemTime
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type Output = SystemTimeThe resulting type after applying the + operator.
fn add(self, dur: Duration) -> SystemTime
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Performs the + operation.
impl AddAssign<Duration> for SystemTime
fn add_assign(&mut self, other: Duration)
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Performs the += operation.
impl Sub<Duration> for SystemTime
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type Output = SystemTimeThe resulting type after applying the - operator.
fn sub(self, dur: Duration) -> SystemTime
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Performs the - operation.
impl SubAssign<Duration> for SystemTime
fn sub_assign(&mut self, other: Duration)
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Performs the -= operation.
impl Debug for SystemTime
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fn fmt(&self, f: &mut Formatter) -> Result
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Formats the value using the given formatter. Read more
© 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.SystemTime.html