# Constant std::time::UNIX_EPOCH

1.8.0 · source ·

    pub const UNIX_EPOCH: SystemTime;

Expand description

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.

`duration_since(UNIX_EPOCH).unwrap().as_secs()` returns the number of non-leap seconds since the start of 1970 UTC. This is a POSIX `time_t` (as a `u64`), and is the same time representation as used in many Internet protocols.

## Examples

    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!"),
    }

Run