rust/library/std/src/time.rs
Michael Howell 2cdec46275 docs: remove colon from time header
It's not used anywhere else; the inconsistency is weird.
2023-01-28 16:07:34 -07:00

695 lines
26 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//! Temporal quantification.
//!
//! # Examples
//!
//! There are multiple ways to create a new [`Duration`]:
//!
//! ```
//! # use std::time::Duration;
//! let five_seconds = Duration::from_secs(5);
//! assert_eq!(five_seconds, Duration::from_millis(5_000));
//! assert_eq!(five_seconds, Duration::from_micros(5_000_000));
//! assert_eq!(five_seconds, Duration::from_nanos(5_000_000_000));
//!
//! let ten_seconds = Duration::from_secs(10);
//! let seven_nanos = Duration::from_nanos(7);
//! let total = ten_seconds + seven_nanos;
//! assert_eq!(total, Duration::new(10, 7));
//! ```
//!
//! Using [`Instant`] to calculate how long a function took to run:
//!
//! ```ignore (incomplete)
//! let now = Instant::now();
//!
//! // Calling a slow function, it may take a while
//! slow_function();
//!
//! let elapsed_time = now.elapsed();
//! println!("Running slow_function() took {} seconds.", elapsed_time.as_secs());
//! ```
#![stable(feature = "time", since = "1.3.0")]
#[cfg(test)]
mod tests;
use crate::error::Error;
use crate::fmt;
use crate::ops::{Add, AddAssign, Sub, SubAssign};
use crate::sys::time;
use crate::sys_common::{FromInner, IntoInner};
#[stable(feature = "time", since = "1.3.0")]
pub use core::time::Duration;
#[stable(feature = "duration_checked_float", since = "1.66.0")]
pub use core::time::TryFromFloatSecsError;
/// A measurement of a monotonically nondecreasing clock.
/// Opaque and useful only with [`Duration`].
///
/// Instants are always guaranteed, barring [platform bugs], 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 might 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:
///
/// ```no_run
/// 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());
/// }
/// ```
///
/// [platform bugs]: Instant#monotonicity
///
/// # OS-specific behaviors
///
/// An `Instant` is a wrapper around system-specific types and it may behave
/// differently depending on the underlying operating system. For example,
/// the following snippet is fine on Linux but panics on macOS:
///
/// ```no_run
/// use std::time::{Instant, Duration};
///
/// let now = Instant::now();
/// let max_seconds = u64::MAX / 1_000_000_000;
/// let duration = Duration::new(max_seconds, 0);
/// println!("{:?}", now + duration);
/// ```
///
/// # Underlying System calls
///
/// The following system calls are [currently] being used by `now()` to find out
/// the current time:
///
/// | Platform | System call |
/// |-----------|----------------------------------------------------------------------|
/// | SGX | [`insecure_time` usercall]. More information on [timekeeping in SGX] |
/// | UNIX | [clock_gettime (Monotonic Clock)] |
/// | Darwin | [mach_absolute_time] |
/// | VXWorks | [clock_gettime (Monotonic Clock)] |
/// | SOLID | `get_tim` |
/// | WASI | [__wasi_clock_time_get (Monotonic Clock)] |
/// | Windows | [QueryPerformanceCounter] |
///
/// [currently]: crate::io#platform-specific-behavior
/// [QueryPerformanceCounter]: https://docs.microsoft.com/en-us/windows/win32/api/profileapi/nf-profileapi-queryperformancecounter
/// [`insecure_time` usercall]: https://edp.fortanix.com/docs/api/fortanix_sgx_abi/struct.Usercalls.html#method.insecure_time
/// [timekeeping in SGX]: https://edp.fortanix.com/docs/concepts/rust-std/#codestdtimecode
/// [__wasi_clock_time_get (Monotonic Clock)]: https://github.com/WebAssembly/WASI/blob/master/phases/snapshot/docs.md#clock_time_get
/// [clock_gettime (Monotonic Clock)]: https://linux.die.net/man/3/clock_gettime
/// [mach_absolute_time]: https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/KernelProgramming/services/services.html
///
/// **Disclaimer:** These system calls might change over time.
///
/// > Note: mathematical operations like [`add`] may panic if the underlying
/// > structure cannot represent the new point in time.
///
/// [`add`]: Instant::add
///
/// ## Monotonicity
///
/// On all platforms `Instant` will try to use an OS API that guarantees monotonic behavior
/// if available, which is the case for all [tier 1] platforms.
/// In practice such guarantees are under rare circumstances broken by hardware, virtualization
/// or operating system bugs. To work around these bugs and platforms not offering monotonic clocks
/// [`duration_since`], [`elapsed`] and [`sub`] saturate to zero. In older Rust versions this
/// lead to a panic instead. [`checked_duration_since`] can be used to detect and handle situations
/// where monotonicity is violated, or `Instant`s are subtracted in the wrong order.
///
/// This workaround obscures programming errors where earlier and later instants are accidentally
/// swapped. For this reason future rust versions may reintroduce panics.
///
/// [tier 1]: https://doc.rust-lang.org/rustc/platform-support.html
/// [`duration_since`]: Instant::duration_since
/// [`elapsed`]: Instant::elapsed
/// [`sub`]: Instant::sub
/// [`checked_duration_since`]: Instant::checked_duration_since
///
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[stable(feature = "time2", since = "1.8.0")]
pub struct Instant(time::Instant);
/// 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.
///
/// The size of a `SystemTime` struct may vary depending on the target operating
/// system.
///
/// Example:
///
/// ```no_run
/// 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:?}");
/// }
/// }
/// }
/// ```
///
/// # Platform-specific behavior
///
/// The precision of `SystemTime` can depend on the underlying OS-specific time format.
/// For example, on Windows the time is represented in 100 nanosecond intervals whereas Linux
/// can represent nanosecond intervals.
///
/// The following system calls are [currently] being used by `now()` to find out
/// the current time:
///
/// | Platform | System call |
/// |-----------|----------------------------------------------------------------------|
/// | SGX | [`insecure_time` usercall]. More information on [timekeeping in SGX] |
/// | UNIX | [clock_gettime (Realtime Clock)] |
/// | Darwin | [gettimeofday] |
/// | VXWorks | [clock_gettime (Realtime Clock)] |
/// | SOLID | `SOLID_RTC_ReadTime` |
/// | WASI | [__wasi_clock_time_get (Realtime Clock)] |
/// | Windows | [GetSystemTimePreciseAsFileTime] / [GetSystemTimeAsFileTime] |
///
/// [currently]: crate::io#platform-specific-behavior
/// [`insecure_time` usercall]: https://edp.fortanix.com/docs/api/fortanix_sgx_abi/struct.Usercalls.html#method.insecure_time
/// [timekeeping in SGX]: https://edp.fortanix.com/docs/concepts/rust-std/#codestdtimecode
/// [gettimeofday]: https://man7.org/linux/man-pages/man2/gettimeofday.2.html
/// [clock_gettime (Realtime Clock)]: https://linux.die.net/man/3/clock_gettime
/// [__wasi_clock_time_get (Realtime Clock)]: https://github.com/WebAssembly/WASI/blob/master/phases/snapshot/docs.md#clock_time_get
/// [GetSystemTimePreciseAsFileTime]: https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime
/// [GetSystemTimeAsFileTime]: https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime
///
/// **Disclaimer:** These system calls might change over time.
///
/// > Note: mathematical operations like [`add`] may panic if the underlying
/// > structure cannot represent the new point in time.
///
/// [`add`]: SystemTime::add
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[stable(feature = "time2", since = "1.8.0")]
pub struct SystemTime(time::SystemTime);
/// An error returned from the `duration_since` and `elapsed` methods on
/// `SystemTime`, used to learn how far in the opposite direction a system time
/// lies.
///
/// # Examples
///
/// ```no_run
/// use std::thread::sleep;
/// use std::time::{Duration, SystemTime};
///
/// let sys_time = SystemTime::now();
/// sleep(Duration::from_secs(1));
/// let new_sys_time = SystemTime::now();
/// match sys_time.duration_since(new_sys_time) {
/// Ok(_) => {}
/// Err(e) => println!("SystemTimeError difference: {:?}", e.duration()),
/// }
/// ```
#[derive(Clone, Debug)]
#[stable(feature = "time2", since = "1.8.0")]
pub struct SystemTimeError(Duration);
impl Instant {
/// Returns an instant corresponding to "now".
///
/// # Examples
///
/// ```
/// use std::time::Instant;
///
/// let now = Instant::now();
/// ```
#[must_use]
#[stable(feature = "time2", since = "1.8.0")]
pub fn now() -> Instant {
Instant(time::Instant::now())
}
/// Returns the amount of time elapsed from another instant to this one,
/// or zero duration if that instant is later than this one.
///
/// # Panics
///
/// Previous rust versions panicked when `earlier` was later than `self`. Currently this
/// method saturates. Future versions may reintroduce the panic in some circumstances.
/// See [Monotonicity].
///
/// [Monotonicity]: Instant#monotonicity
///
/// # Examples
///
/// ```no_run
/// 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));
/// println!("{:?}", now.duration_since(new_now)); // 0ns
/// ```
#[must_use]
#[stable(feature = "time2", since = "1.8.0")]
pub fn duration_since(&self, earlier: Instant) -> Duration {
self.checked_duration_since(earlier).unwrap_or_default()
}
/// Returns the amount of time elapsed from another instant to this one,
/// or None if that instant is later than this one.
///
/// Due to [monotonicity bugs], even under correct logical ordering of the passed `Instant`s,
/// this method can return `None`.
///
/// [monotonicity bugs]: Instant#monotonicity
///
/// # Examples
///
/// ```no_run
/// 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)); // None
/// ```
#[must_use]
#[stable(feature = "checked_duration_since", since = "1.39.0")]
pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration> {
self.0.checked_sub_instant(&earlier.0)
}
/// Returns the amount of time elapsed from another instant to this one,
/// or zero duration if that instant is later than this one.
///
/// # Examples
///
/// ```no_run
/// 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)); // 0ns
/// ```
#[must_use]
#[stable(feature = "checked_duration_since", since = "1.39.0")]
pub fn saturating_duration_since(&self, earlier: Instant) -> Duration {
self.checked_duration_since(earlier).unwrap_or_default()
}
/// Returns the amount of time elapsed since this instant was created.
///
/// # Panics
///
/// Previous rust versions panicked when the current time was earlier than self. Currently this
/// method returns a Duration of zero in that case. Future versions may reintroduce the panic.
/// See [Monotonicity].
///
/// [Monotonicity]: Instant#monotonicity
///
/// # Examples
///
/// ```no_run
/// 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);
/// ```
#[must_use]
#[stable(feature = "time2", since = "1.8.0")]
pub fn elapsed(&self) -> Duration {
Instant::now() - *self
}
/// 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.
#[stable(feature = "time_checked_add", since = "1.34.0")]
pub fn checked_add(&self, duration: Duration) -> Option<Instant> {
self.0.checked_add_duration(&duration).map(Instant)
}
/// 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.
#[stable(feature = "time_checked_add", since = "1.34.0")]
pub fn checked_sub(&self, duration: Duration) -> Option<Instant> {
self.0.checked_sub_duration(&duration).map(Instant)
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Add<Duration> for Instant {
type Output = Instant;
/// # Panics
///
/// This function may panic if the resulting point in time cannot be represented by the
/// underlying data structure. See [`Instant::checked_add`] for a version without panic.
fn add(self, other: Duration) -> Instant {
self.checked_add(other).expect("overflow when adding duration to instant")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
impl AddAssign<Duration> for Instant {
fn add_assign(&mut self, other: Duration) {
*self = *self + other;
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Sub<Duration> for Instant {
type Output = Instant;
fn sub(self, other: Duration) -> Instant {
self.checked_sub(other).expect("overflow when subtracting duration from instant")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
impl SubAssign<Duration> for Instant {
fn sub_assign(&mut self, other: Duration) {
*self = *self - other;
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Sub<Instant> for Instant {
type Output = Duration;
/// Returns the amount of time elapsed from another instant to this one,
/// or zero duration if that instant is later than this one.
///
/// # Panics
///
/// Previous rust versions panicked when `other` was later than `self`. Currently this
/// method saturates. Future versions may reintroduce the panic in some circumstances.
/// See [Monotonicity].
///
/// [Monotonicity]: Instant#monotonicity
fn sub(self, other: Instant) -> Duration {
self.duration_since(other)
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl fmt::Debug for Instant {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
impl SystemTime {
/// An anchor in time which can be used to create new `SystemTime` instances or
/// learn about where in time a `SystemTime` lies.
///
/// This constant is defined to be "1970-01-01 00:00:00 UTC" on all systems with
/// respect to the system clock. Using `duration_since` on an existing
/// `SystemTime` instance can tell how far away from this point in time a
/// measurement lies, and using `UNIX_EPOCH + duration` can be used to create a
/// `SystemTime` instance to represent another fixed point in time.
///
/// # Examples
///
/// ```no_run
/// use std::time::SystemTime;
///
/// match SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
/// Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
/// Err(_) => panic!("SystemTime before UNIX EPOCH!"),
/// }
/// ```
#[stable(feature = "assoc_unix_epoch", since = "1.28.0")]
pub const UNIX_EPOCH: SystemTime = UNIX_EPOCH;
/// Returns the system time corresponding to "now".
///
/// # Examples
///
/// ```
/// use std::time::SystemTime;
///
/// let sys_time = SystemTime::now();
/// ```
#[must_use]
#[stable(feature = "time2", since = "1.8.0")]
pub fn now() -> SystemTime {
SystemTime(time::SystemTime::now())
}
/// 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).
/// [`Instant`] can be used to measure elapsed time without this risk of failure.
///
/// If successful, <code>[Ok]\([Duration])</code> 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.
///
/// # Examples
///
/// ```no_run
/// use std::time::SystemTime;
///
/// let sys_time = SystemTime::now();
/// let new_sys_time = SystemTime::now();
/// let difference = new_sys_time.duration_since(sys_time)
/// .expect("Clock may have gone backwards");
/// println!("{difference:?}");
/// ```
#[stable(feature = "time2", since = "1.8.0")]
pub fn duration_since(&self, earlier: SystemTime) -> Result<Duration, SystemTimeError> {
self.0.sub_time(&earlier.0).map_err(SystemTimeError)
}
/// Returns the difference between the clock time when this
/// system time was created, and the current clock time.
///
/// 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 might not always succeed. If successful, <code>[Ok]\([Duration])</code> is
/// returned where the duration represents the amount of time elapsed from
/// this time measurement to the current time.
///
/// To measure elapsed time reliably, use [`Instant`] instead.
///
/// 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.
///
/// # Examples
///
/// ```no_run
/// 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);
/// ```
#[stable(feature = "time2", since = "1.8.0")]
pub fn elapsed(&self) -> Result<Duration, SystemTimeError> {
SystemTime::now().duration_since(*self)
}
/// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
/// `SystemTime` (which means it's inside the bounds of the underlying data structure), `None`
/// otherwise.
#[stable(feature = "time_checked_add", since = "1.34.0")]
pub fn checked_add(&self, duration: Duration) -> Option<SystemTime> {
self.0.checked_add_duration(&duration).map(SystemTime)
}
/// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
/// `SystemTime` (which means it's inside the bounds of the underlying data structure), `None`
/// otherwise.
#[stable(feature = "time_checked_add", since = "1.34.0")]
pub fn checked_sub(&self, duration: Duration) -> Option<SystemTime> {
self.0.checked_sub_duration(&duration).map(SystemTime)
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Add<Duration> for SystemTime {
type Output = SystemTime;
/// # Panics
///
/// This function may panic if the resulting point in time cannot be represented by the
/// underlying data structure. See [`SystemTime::checked_add`] for a version without panic.
fn add(self, dur: Duration) -> SystemTime {
self.checked_add(dur).expect("overflow when adding duration to instant")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
impl AddAssign<Duration> for SystemTime {
fn add_assign(&mut self, other: Duration) {
*self = *self + other;
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Sub<Duration> for SystemTime {
type Output = SystemTime;
fn sub(self, dur: Duration) -> SystemTime {
self.checked_sub(dur).expect("overflow when subtracting duration from instant")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
impl SubAssign<Duration> for SystemTime {
fn sub_assign(&mut self, other: Duration) {
*self = *self - other;
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl fmt::Debug for SystemTime {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
/// An anchor in time which can be used to create new `SystemTime` instances or
/// learn about where in time a `SystemTime` lies.
///
/// This constant is defined to be "1970-01-01 00:00:00 UTC" on all systems with
/// respect to the system clock. Using `duration_since` on an existing
/// [`SystemTime`] instance can tell how far away from this point in time a
/// measurement lies, and using `UNIX_EPOCH + duration` can be used to create a
/// [`SystemTime`] instance to represent another fixed point in time.
///
/// # Examples
///
/// ```no_run
/// use std::time::{SystemTime, UNIX_EPOCH};
///
/// match SystemTime::now().duration_since(UNIX_EPOCH) {
/// Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
/// Err(_) => panic!("SystemTime before UNIX EPOCH!"),
/// }
/// ```
#[stable(feature = "time2", since = "1.8.0")]
pub const UNIX_EPOCH: SystemTime = SystemTime(time::UNIX_EPOCH);
impl SystemTimeError {
/// Returns the positive duration which represents how far forward the
/// second system time was from the first.
///
/// A `SystemTimeError` is returned from the [`SystemTime::duration_since`]
/// and [`SystemTime::elapsed`] methods whenever the second system time
/// represents a point later in time than the `self` of the method call.
///
/// # Examples
///
/// ```no_run
/// use std::thread::sleep;
/// use std::time::{Duration, SystemTime};
///
/// let sys_time = SystemTime::now();
/// sleep(Duration::from_secs(1));
/// let new_sys_time = SystemTime::now();
/// match sys_time.duration_since(new_sys_time) {
/// Ok(_) => {}
/// Err(e) => println!("SystemTimeError difference: {:?}", e.duration()),
/// }
/// ```
#[must_use]
#[stable(feature = "time2", since = "1.8.0")]
pub fn duration(&self) -> Duration {
self.0
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl Error for SystemTimeError {
#[allow(deprecated)]
fn description(&self) -> &str {
"other time was not earlier than self"
}
}
#[stable(feature = "time2", since = "1.8.0")]
impl fmt::Display for SystemTimeError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "second time provided was later than self")
}
}
impl FromInner<time::SystemTime> for SystemTime {
fn from_inner(time: time::SystemTime) -> SystemTime {
SystemTime(time)
}
}
impl IntoInner<time::SystemTime> for SystemTime {
fn into_inner(self) -> time::SystemTime {
self.0
}
}