pub struct SystemTime(_);
A measurement of the system clock appropriate for timestamps such as those on files on the filesystem.
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 second. In other words, an
operation that happens after another operation in real time may have an
Consequently, comparing two
SystemTime instances to learn about the
duration between them returns a
Result instead of an infallible
to indicate that this sort of time drift may happen and needs to be handled.
SystemTime cannot be directly inspected, the
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.
fn now() -> SystemTime
Returns the system time corresponding to "now".
fn duration_from_earlier(&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).
Ok(Duration) is returned where the duration represents
the amount of time elapsed from the specified measurement to this one.
earlier is later than
self, and the error
contains how far from
self the time is.
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,
returned where the duration represents the amount of time elapsed from
this time measurement to the current time.
self is later than the current system time, and
the error contains how far from the current system time