std::time::Instant - Rust
Description: API documentation for the Rust `Instant` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, Instant

# Struct std::time::Instant 1.8.0 [−] [src]

    pub struct 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).

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`
[src]

#### `pub fn now() -> Instant`
[src]

Returns an instant corresponding to "now".

# Examples

    use std::time::Instant;

    let now = Instant::now();Run

#### `pub fn duration_since(&self, earlier: Instant) -> Duration`
[src]

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 elapsed(&self) -> Duration`
[src]

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

## Trait Implementations

### `impl Copy for Instant`
[src]

### `impl Clone for Instant`
[src]

#### `fn clone(&self) -> Instant`
[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`
1.0.0
[src]

Performs copy-assignment from `source`. Read more

### `impl PartialEq for Instant`
[src]

#### `fn eq(&self, __arg_0: &Instant) -> bool`
[src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, __arg_0: &Instant) -> bool`
[src]

This method tests for `!=`.

### `impl Eq for Instant`
[src]

### `impl PartialOrd for Instant`
[src]

#### `fn partial_cmp(&self, __arg_0: &Instant) -> Option<Ordering>`
[src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `fn lt(&self, __arg_0: &Instant) -> bool`
[src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `fn le(&self, __arg_0: &Instant) -> bool`
[src]

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`
[src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `fn ge(&self, __arg_0: &Instant) -> bool`
[src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl Ord for Instant`
[src]

#### `fn cmp(&self, __arg_0: &Instant) -> Ordering`
[src]

This method returns an `Ordering` between `self` and `other`. Read more

#### `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

### `impl Add<Duration> for Instant`
[src]

#### `type Output = Instant`

The resulting type after applying the `+` operator.

#### `fn add(self, other: Duration) -> Instant`
[src]

Performs the `+` operation.

### `impl AddAssign<Duration> for Instant`
1.9.0
[src]

#### `fn add_assign(&mut self, other: Duration)`
[src]

Performs the `+=` operation.

### `impl Sub<Duration> for Instant`
[src]

#### `type Output = Instant`

The resulting type after applying the `-` operator.

#### `fn sub(self, other: Duration) -> Instant`
[src]

Performs the `-` operation.

### `impl SubAssign<Duration> for Instant`
1.9.0
[src]

#### `fn sub_assign(&mut self, other: Duration)`
[src]

Performs the `-=` operation.

### `impl Sub<Instant> for Instant`
[src]

#### `type Output = Duration`

The resulting type after applying the `-` operator.

#### `fn sub(self, other: Instant) -> Duration`
[src]

Performs the `-` operation.

### `impl Debug for Instant`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`
[src]

Formats the value using the given formatter.

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