Struct std::time::SystemTime 1.8.0[−][src]
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.
The size of a SystemTime struct may vary depending on the target operating
system.
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); } } }Run
Methods
impl SystemTime[src]
impl SystemTimepub const UNIX_EPOCH: SystemTime
UNIX_EPOCH: SystemTime = UNIX_EPOCH
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
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!"), }Run
pub fn now() -> SystemTime[src]
pub fn now() -> SystemTimeReturns the system time corresponding to "now".
Examples
use std::time::SystemTime; let sys_time = SystemTime::now();Run
pub fn duration_since(
&self,
earlier: SystemTime
) -> Result<Duration, SystemTimeError>[src]
pub fn duration_since(
&self,
earlier: SystemTime
) -> Result<Duration, SystemTimeError>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.
Examples
use std::time::SystemTime; let sys_time = SystemTime::now(); let difference = sys_time.duration_since(sys_time) .expect("SystemTime::duration_since failed"); println!("{:?}", difference);Run
pub fn elapsed(&self) -> Result<Duration, SystemTimeError>[src]
pub fn elapsed(&self) -> Result<Duration, SystemTimeError>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.
Examples
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);Run
Trait Implementations
impl Copy for SystemTime[src]
impl Copy for SystemTimeimpl Clone for SystemTime[src]
impl Clone for SystemTimefn clone(&self) -> SystemTime[src]
fn clone(&self) -> SystemTimeReturns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)1.0.0[src]
fn clone_from(&mut self, source: &Self)Performs copy-assignment from source. Read more
impl PartialEq for SystemTime[src]
impl PartialEq for SystemTimefn eq(&self, other: &SystemTime) -> bool[src]
fn eq(&self, other: &SystemTime) -> boolThis method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, other: &SystemTime) -> bool[src]
fn ne(&self, other: &SystemTime) -> boolThis method tests for !=.
impl Eq for SystemTime[src]
impl Eq for SystemTimeimpl PartialOrd for SystemTime[src]
impl PartialOrd for SystemTimefn partial_cmp(&self, other: &SystemTime) -> Option<Ordering>[src]
fn partial_cmp(&self, other: &SystemTime) -> Option<Ordering>This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, other: &SystemTime) -> bool[src]
fn lt(&self, other: &SystemTime) -> boolThis method tests less than (for self and other) and is used by the < operator. Read more
fn le(&self, other: &SystemTime) -> bool[src]
fn le(&self, other: &SystemTime) -> boolThis method tests less than or equal to (for self and other) and is used by the <= operator. Read more
fn gt(&self, other: &SystemTime) -> bool[src]
fn gt(&self, other: &SystemTime) -> boolThis method tests greater than (for self and other) and is used by the > operator. Read more
fn ge(&self, other: &SystemTime) -> bool[src]
fn ge(&self, other: &SystemTime) -> boolThis method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl Ord for SystemTime[src]
impl Ord for SystemTimefn cmp(&self, other: &SystemTime) -> Ordering[src]
fn cmp(&self, other: &SystemTime) -> OrderingThis method returns an Ordering between self and other. Read more
fn max(self, other: Self) -> Self1.21.0[src]
fn max(self, other: Self) -> SelfCompares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self1.21.0[src]
fn min(self, other: Self) -> SelfCompares and returns the minimum of two values. Read more
impl Hash for SystemTime[src]
impl Hash for SystemTimefn hash<__H: Hasher>(&self, state: &mut __H)[src]
fn hash<__H: Hasher>(&self, state: &mut __H)Feeds this value into the given [Hasher]. Read more
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher, 1.3.0[src]
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher, Feeds a slice of this type into the given [Hasher]. Read more
impl Add<Duration> for SystemTime[src]
impl Add<Duration> for SystemTimetype Output = SystemTime
The resulting type after applying the + operator.
fn add(self, dur: Duration) -> SystemTime[src]
fn add(self, dur: Duration) -> SystemTimePerforms the + operation.
impl AddAssign<Duration> for SystemTime1.9.0[src]
impl AddAssign<Duration> for SystemTimefn add_assign(&mut self, other: Duration)[src]
fn add_assign(&mut self, other: Duration)Performs the += operation.
impl Sub<Duration> for SystemTime[src]
impl Sub<Duration> for SystemTimetype Output = SystemTime
The resulting type after applying the - operator.
fn sub(self, dur: Duration) -> SystemTime[src]
fn sub(self, dur: Duration) -> SystemTimePerforms the - operation.
impl SubAssign<Duration> for SystemTime1.9.0[src]
impl SubAssign<Duration> for SystemTimefn sub_assign(&mut self, other: Duration)[src]
fn sub_assign(&mut self, other: Duration)Performs the -= operation.
impl Debug for SystemTime[src]
impl Debug for SystemTimeAuto Trait Implementations
impl Send for SystemTime
impl Send for SystemTimeimpl Sync for SystemTime
impl Sync for SystemTime