Struct chrono::NaiveTime

pub struct NaiveTime { /* private fields */ }

ISO 8601 time without timezone. Allows for the nanosecond precision and optional leap second representation.

Leap Second Handling

Since 1960s, the manmade atomic clock has been so accurate that it is much more accurate than Earth’s own motion. It became desirable to define the civil time in terms of the atomic clock, but that risks the desynchronization of the civil time from Earth. To account for this, the designers of the Coordinated Universal Time (UTC) made that the UTC should be kept within 0.9 seconds of the observed Earth-bound time. When the mean solar day is longer than the ideal (86,400 seconds), the error slowly accumulates and it is necessary to add a leap second to slow the UTC down a bit. (We may also remove a second to speed the UTC up a bit, but it never happened.) The leap second, if any, follows 23:59:59 of June 30 or December 31 in the UTC.

Fast forward to the 21st century, we have seen 26 leap seconds from January 1972 to December 2015. Yes, 26 seconds. Probably you can read this paragraph within 26 seconds. But those 26 seconds, and possibly more in the future, are never predictable, and whether to add a leap second or not is known only before 6 months. Internet-based clocks (via NTP) do account for known leap seconds, but the system API normally doesn’t (and often can’t, with no network connection) and there is no reliable way to retrieve leap second information.

Chrono does not try to accurately implement leap seconds; it is impossible. Rather, it allows for leap seconds but behaves as if there are no other leap seconds. Various operations will ignore any possible leap second(s) except when any of the operands were actually leap seconds.

If you cannot tolerate this behavior, you must use a separate TimeZone for the International Atomic Time (TAI). TAI is like UTC but has no leap seconds, and thus slightly differs from UTC. Chrono does not yet provide such implementation, but it is planned.

Representing Leap Seconds

The leap second is indicated via fractional seconds more than 1 second. This makes possible to treat a leap second as the prior non-leap second if you don’t care about sub-second accuracy. You should use the proper formatting to get the raw leap second.

All methods accepting fractional seconds will accept such values.

use chrono::{NaiveDate, NaiveTime};

let t = NaiveTime::from_hms_milli_opt(8, 59, 59, 1_000).unwrap();

let dt1 = NaiveDate::from_ymd_opt(2015, 7, 1)
    .unwrap()
    .and_hms_micro_opt(8, 59, 59, 1_000_000)
    .unwrap();

let dt2 = NaiveDate::from_ymd_opt(2015, 6, 30)
    .unwrap()
    .and_hms_nano_opt(23, 59, 59, 1_000_000_000)
    .unwrap()
    .and_utc();

Note that the leap second can happen anytime given an appropriate time zone; 2015-07-01 01:23:60 would be a proper leap second if UTC+01:24 had existed. Practically speaking, though, by the time of the first leap second on 1972-06-30, every time zone offset around the world has standardized to the 5-minute alignment.

Date And Time Arithmetics

As a concrete example, let’s assume that 03:00:60 and 04:00:60 are leap seconds. In reality, of course, leap seconds are separated by at least 6 months. We will also use some intuitive concise notations for the explanation.

Time + TimeDelta (short for NaiveTime::overflowing_add_signed):

• 03:00:00 + 1s = 03:00:01.
• 03:00:59 + 60s = 03:01:59.
• 03:00:59 + 61s = 03:02:00.
• 03:00:59 + 1s = 03:01:00.
• 03:00:60 + 1s = 03:01:00. Note that the sum is identical to the previous.
• 03:00:60 + 60s = 03:01:59.
• 03:00:60 + 61s = 03:02:00.
• 03:00:60.1 + 0.8s = 03:00:60.9.

Time - TimeDelta (short for NaiveTime::overflowing_sub_signed):

• 03:00:00 - 1s = 02:59:59.
• 03:01:00 - 1s = 03:00:59.
• 03:01:00 - 60s = 03:00:00.
• 03:00:60 - 60s = 03:00:00. Note that the result is identical to the previous.
• 03:00:60.7 - 0.4s = 03:00:60.3.
• 03:00:60.7 - 0.9s = 03:00:59.8.

Time - Time (short for NaiveTime::signed_duration_since):

• 04:00:00 - 03:00:00 = 3600s.
• 03:01:00 - 03:00:00 = 60s.
• 03:00:60 - 03:00:00 = 60s. Note that the difference is identical to the previous.
• 03:00:60.6 - 03:00:59.4 = 1.2s.
• 03:01:00 - 03:00:59.8 = 0.2s.
• 03:01:00 - 03:00:60.5 = 0.5s. Note that the difference is larger than the previous, even though the leap second clearly follows the previous whole second.
• 04:00:60.9 - 03:00:60.1 = (04:00:60.9 - 04:00:00) + (04:00:00 - 03:01:00) + (03:01:00 - 03:00:60.1) = 60.9s + 3540s + 0.9s = 3601.8s.

In general,

• Time + TimeDelta unconditionally equals to TimeDelta + Time.

• Time - TimeDelta unconditionally equals to Time + (-TimeDelta).

• Time1 - Time2 unconditionally equals to -(Time2 - Time1).

• Associativity does not generally hold, because (Time + TimeDelta1) - TimeDelta2 no longer equals to Time + (TimeDelta1 - TimeDelta2) for two positive durations.

  • As a special case, (Time + TimeDelta) - TimeDelta also does not equal to Time.

  • If you can assume that all durations have the same sign, however, then the associativity holds: (Time + TimeDelta1) + TimeDelta2 equals to Time + (TimeDelta1 + TimeDelta2) for two positive durations.

Reading And Writing Leap Seconds

The “typical” leap seconds on the minute boundary are correctly handled both in the formatting and parsing. The leap second in the human-readable representation will be represented as the second part being 60, as required by ISO 8601.

use chrono::NaiveDate;

let dt = NaiveDate::from_ymd_opt(2015, 6, 30)
    .unwrap()
    .and_hms_milli_opt(23, 59, 59, 1_000)
    .unwrap()
    .and_utc();
assert_eq!(format!("{:?}", dt), "2015-06-30T23:59:60Z");

There are hypothetical leap seconds not on the minute boundary nevertheless supported by Chrono. They are allowed for the sake of completeness and consistency; there were several “exotic” time zone offsets with fractional minutes prior to UTC after all. For such cases the human-readable representation is ambiguous and would be read back to the next non-leap second.

A NaiveTime with a leap second that is not on a minute boundary can only be created from a DateTime with fractional minutes as offset, or using Timelike::with_nanosecond().

use chrono::{FixedOffset, NaiveDate, TimeZone};

let paramaribo_pre1945 = FixedOffset::east_opt(-13236).unwrap(); // -03:40:36
let leap_sec_2015 =
    NaiveDate::from_ymd_opt(2015, 6, 30).unwrap().and_hms_milli_opt(23, 59, 59, 1_000).unwrap();
let dt1 = paramaribo_pre1945.from_utc_datetime(&leap_sec_2015);
assert_eq!(format!("{:?}", dt1), "2015-06-30T20:19:24-03:40:36");
assert_eq!(format!("{:?}", dt1.time()), "20:19:24");

let next_sec = NaiveDate::from_ymd_opt(2015, 7, 1).unwrap().and_hms_opt(0, 0, 0).unwrap();
let dt2 = paramaribo_pre1945.from_utc_datetime(&next_sec);
assert_eq!(format!("{:?}", dt2), "2015-06-30T20:19:24-03:40:36");
assert_eq!(format!("{:?}", dt2.time()), "20:19:24");

assert!(dt1.time() != dt2.time());
assert!(dt1.time().to_string() == dt2.time().to_string());

Since Chrono alone cannot determine any existence of leap seconds, there is absolutely no guarantee that the leap second read has actually happened.

Implementations

impl NaiveTime

pub const fn from_hms(hour: u32, min: u32, sec: u32) -> NaiveTime

👎Deprecated since 0.4.23: use from_hms_opt() instead

Makes a new NaiveTime from hour, minute and second.

No leap second is allowed here; use NaiveTime::from_hms_* methods with a subsecond parameter instead.

Panics

Panics on invalid hour, minute and/or second.

pub const fn from_hms_opt(hour: u32, min: u32, sec: u32) -> Option<NaiveTime>

Makes a new NaiveTime from hour, minute and second.

The millisecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Errors

Returns None on invalid hour, minute and/or second.

Example

use chrono::NaiveTime;

let from_hms_opt = NaiveTime::from_hms_opt;

assert!(from_hms_opt(0, 0, 0).is_some());
assert!(from_hms_opt(23, 59, 59).is_some());
assert!(from_hms_opt(24, 0, 0).is_none());
assert!(from_hms_opt(23, 60, 0).is_none());
assert!(from_hms_opt(23, 59, 60).is_none());

pub const fn from_hms_milli( hour: u32, min: u32, sec: u32, milli: u32 ) -> NaiveTime

👎Deprecated since 0.4.23: use from_hms_milli_opt() instead

Makes a new NaiveTime from hour, minute, second and millisecond.

The millisecond part can exceed 1,000 in order to represent the leap second.

Panics

Panics on invalid hour, minute, second and/or millisecond.

pub const fn from_hms_milli_opt( hour: u32, min: u32, sec: u32, milli: u32 ) -> Option<NaiveTime>

Makes a new NaiveTime from hour, minute, second and millisecond.

The millisecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Errors

Returns None on invalid hour, minute, second and/or millisecond.

Example

use chrono::NaiveTime;

let from_hmsm_opt = NaiveTime::from_hms_milli_opt;

assert!(from_hmsm_opt(0, 0, 0, 0).is_some());
assert!(from_hmsm_opt(23, 59, 59, 999).is_some());
assert!(from_hmsm_opt(23, 59, 59, 1_999).is_some()); // a leap second after 23:59:59
assert!(from_hmsm_opt(24, 0, 0, 0).is_none());
assert!(from_hmsm_opt(23, 60, 0, 0).is_none());
assert!(from_hmsm_opt(23, 59, 60, 0).is_none());
assert!(from_hmsm_opt(23, 59, 59, 2_000).is_none());

pub const fn from_hms_micro( hour: u32, min: u32, sec: u32, micro: u32 ) -> NaiveTime

👎Deprecated since 0.4.23: use from_hms_micro_opt() instead

Makes a new NaiveTime from hour, minute, second and microsecond.

The microsecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Panics

Panics on invalid hour, minute, second and/or microsecond.

pub const fn from_hms_micro_opt( hour: u32, min: u32, sec: u32, micro: u32 ) -> Option<NaiveTime>

Makes a new NaiveTime from hour, minute, second and microsecond.

The microsecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Errors

Returns None on invalid hour, minute, second and/or microsecond.

Example

use chrono::NaiveTime;

let from_hmsu_opt = NaiveTime::from_hms_micro_opt;

assert!(from_hmsu_opt(0, 0, 0, 0).is_some());
assert!(from_hmsu_opt(23, 59, 59, 999_999).is_some());
assert!(from_hmsu_opt(23, 59, 59, 1_999_999).is_some()); // a leap second after 23:59:59
assert!(from_hmsu_opt(24, 0, 0, 0).is_none());
assert!(from_hmsu_opt(23, 60, 0, 0).is_none());
assert!(from_hmsu_opt(23, 59, 60, 0).is_none());
assert!(from_hmsu_opt(23, 59, 59, 2_000_000).is_none());

pub const fn from_hms_nano( hour: u32, min: u32, sec: u32, nano: u32 ) -> NaiveTime

👎Deprecated since 0.4.23: use from_hms_nano_opt() instead

Makes a new NaiveTime from hour, minute, second and nanosecond.

The nanosecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Panics

Panics on invalid hour, minute, second and/or nanosecond.

pub const fn from_hms_nano_opt( hour: u32, min: u32, sec: u32, nano: u32 ) -> Option<NaiveTime>

Makes a new NaiveTime from hour, minute, second and nanosecond.

The nanosecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when sec == 59.

Errors

Returns None on invalid hour, minute, second and/or nanosecond.

Example

use chrono::NaiveTime;

let from_hmsn_opt = NaiveTime::from_hms_nano_opt;

assert!(from_hmsn_opt(0, 0, 0, 0).is_some());
assert!(from_hmsn_opt(23, 59, 59, 999_999_999).is_some());
assert!(from_hmsn_opt(23, 59, 59, 1_999_999_999).is_some()); // a leap second after 23:59:59
assert!(from_hmsn_opt(24, 0, 0, 0).is_none());
assert!(from_hmsn_opt(23, 60, 0, 0).is_none());
assert!(from_hmsn_opt(23, 59, 60, 0).is_none());
assert!(from_hmsn_opt(23, 59, 59, 2_000_000_000).is_none());

pub const fn from_num_seconds_from_midnight(secs: u32, nano: u32) -> NaiveTime

👎Deprecated since 0.4.23: use from_num_seconds_from_midnight_opt() instead

Makes a new NaiveTime from the number of seconds since midnight and nanosecond.

The nanosecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when secs % 60 == 59.

Panics

Panics on invalid number of seconds and/or nanosecond.

pub const fn from_num_seconds_from_midnight_opt( secs: u32, nano: u32 ) -> Option<NaiveTime>

Makes a new NaiveTime from the number of seconds since midnight and nanosecond.

The nanosecond part is allowed to exceed 1,000,000,000 in order to represent a leap second, but only when secs % 60 == 59.

Errors

Returns None on invalid number of seconds and/or nanosecond.

Example

use chrono::NaiveTime;

let from_nsecs_opt = NaiveTime::from_num_seconds_from_midnight_opt;

assert!(from_nsecs_opt(0, 0).is_some());
assert!(from_nsecs_opt(86399, 999_999_999).is_some());
assert!(from_nsecs_opt(86399, 1_999_999_999).is_some()); // a leap second after 23:59:59
assert!(from_nsecs_opt(86_400, 0).is_none());
assert!(from_nsecs_opt(86399, 2_000_000_000).is_none());

pub fn parse_from_str(s: &str, fmt: &str) -> ParseResult<NaiveTime>

Parses a string with the specified format string and returns a new NaiveTime. See the format::strftime module on the supported escape sequences.

Example

use chrono::NaiveTime;

let parse_from_str = NaiveTime::parse_from_str;

assert_eq!(
    parse_from_str("23:56:04", "%H:%M:%S"),
    Ok(NaiveTime::from_hms_opt(23, 56, 4).unwrap())
);
assert_eq!(
    parse_from_str("pm012345.6789", "%p%I%M%S%.f"),
    Ok(NaiveTime::from_hms_micro_opt(13, 23, 45, 678_900).unwrap())
);

Date and offset is ignored for the purpose of parsing.

assert_eq!(
    parse_from_str("2014-5-17T12:34:56+09:30", "%Y-%m-%dT%H:%M:%S%z"),
    Ok(NaiveTime::from_hms_opt(12, 34, 56).unwrap())
);

Leap seconds are correctly handled by treating any time of the form hh:mm:60 as a leap second. (This equally applies to the formatting, so the round trip is possible.)

assert_eq!(
    parse_from_str("08:59:60.123", "%H:%M:%S%.f"),
    Ok(NaiveTime::from_hms_milli_opt(8, 59, 59, 1_123).unwrap())
);

Missing seconds are assumed to be zero, but out-of-bound times or insufficient fields are errors otherwise.

assert_eq!(parse_from_str("7:15", "%H:%M"), Ok(NaiveTime::from_hms_opt(7, 15, 0).unwrap()));

assert!(parse_from_str("04m33s", "%Mm%Ss").is_err());
assert!(parse_from_str("12", "%H").is_err());
assert!(parse_from_str("17:60", "%H:%M").is_err());
assert!(parse_from_str("24:00:00", "%H:%M:%S").is_err());

All parsed fields should be consistent to each other, otherwise it’s an error. Here %H is for 24-hour clocks, unlike %I, and thus can be independently determined without AM/PM.

assert!(parse_from_str("13:07 AM", "%H:%M %p").is_err());

pub fn parse_and_remainder<'a>( s: &'a str, fmt: &str ) -> ParseResult<(NaiveTime, &'a str)>

Parses a string from a user-specified format into a new NaiveTime value, and a slice with the remaining portion of the string. See the format::strftime module on the supported escape sequences.

Similar to parse_from_str.

Example

let (time, remainder) =
    NaiveTime::parse_and_remainder("3h4m33s trailing text", "%-Hh%-Mm%-Ss").unwrap();
assert_eq!(time, NaiveTime::from_hms_opt(3, 4, 33).unwrap());
assert_eq!(remainder, " trailing text");

pub const fn overflowing_add_signed(&self, rhs: TimeDelta) -> (NaiveTime, i64)

Adds given TimeDelta to the current time, and also returns the number of seconds in the integral number of days ignored from the addition.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hms = |h, m, s| NaiveTime::from_hms_opt(h, m, s).unwrap();

assert_eq!(
    from_hms(3, 4, 5).overflowing_add_signed(TimeDelta::try_hours(11).unwrap()),
    (from_hms(14, 4, 5), 0)
);
assert_eq!(
    from_hms(3, 4, 5).overflowing_add_signed(TimeDelta::try_hours(23).unwrap()),
    (from_hms(2, 4, 5), 86_400)
);
assert_eq!(
    from_hms(3, 4, 5).overflowing_add_signed(TimeDelta::try_hours(-7).unwrap()),
    (from_hms(20, 4, 5), -86_400)
);

pub const fn overflowing_sub_signed(&self, rhs: TimeDelta) -> (NaiveTime, i64)

Subtracts given TimeDelta from the current time, and also returns the number of seconds in the integral number of days ignored from the subtraction.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hms = |h, m, s| NaiveTime::from_hms_opt(h, m, s).unwrap();

assert_eq!(
    from_hms(3, 4, 5).overflowing_sub_signed(TimeDelta::try_hours(2).unwrap()),
    (from_hms(1, 4, 5), 0)
);
assert_eq!(
    from_hms(3, 4, 5).overflowing_sub_signed(TimeDelta::try_hours(17).unwrap()),
    (from_hms(10, 4, 5), 86_400)
);
assert_eq!(
    from_hms(3, 4, 5).overflowing_sub_signed(TimeDelta::try_hours(-22).unwrap()),
    (from_hms(1, 4, 5), -86_400)
);

pub const fn signed_duration_since(self, rhs: NaiveTime) -> TimeDelta

Subtracts another NaiveTime from the current time. Returns a TimeDelta within +/- 1 day. This does not overflow or underflow at all.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when any of the NaiveTimes themselves represents a leap second in which case the assumption becomes that there are exactly one (or two) leap second(s) ever.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();
let since = NaiveTime::signed_duration_since;

assert_eq!(since(from_hmsm(3, 5, 7, 900), from_hmsm(3, 5, 7, 900)), TimeDelta::zero());
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(3, 5, 7, 875)),
    TimeDelta::try_milliseconds(25).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(3, 5, 6, 925)),
    TimeDelta::try_milliseconds(975).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(3, 5, 0, 900)),
    TimeDelta::try_seconds(7).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(3, 0, 7, 900)),
    TimeDelta::try_seconds(5 * 60).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(0, 5, 7, 900)),
    TimeDelta::try_seconds(3 * 3600).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(4, 5, 7, 900)),
    TimeDelta::try_seconds(-3600).unwrap()
);
assert_eq!(
    since(from_hmsm(3, 5, 7, 900), from_hmsm(2, 4, 6, 800)),
    TimeDelta::try_seconds(3600 + 60 + 1).unwrap() + TimeDelta::try_milliseconds(100).unwrap()
);

Leap seconds are handled, but the subtraction assumes that there were no other leap seconds happened.

assert_eq!(since(from_hmsm(3, 0, 59, 1_000), from_hmsm(3, 0, 59, 0)),
           TimeDelta::try_seconds(1).unwrap());
assert_eq!(since(from_hmsm(3, 0, 59, 1_500), from_hmsm(3, 0, 59, 0)),
           TimeDelta::try_milliseconds(1500).unwrap());
assert_eq!(since(from_hmsm(3, 0, 59, 1_000), from_hmsm(3, 0, 0, 0)),
           TimeDelta::try_seconds(60).unwrap());
assert_eq!(since(from_hmsm(3, 0, 0, 0), from_hmsm(2, 59, 59, 1_000)),
           TimeDelta::try_seconds(1).unwrap());
assert_eq!(since(from_hmsm(3, 0, 59, 1_000), from_hmsm(2, 59, 59, 1_000)),
           TimeDelta::try_seconds(61).unwrap());

pub fn format_with_items<'a, I, B>(&self, items: I) -> DelayedFormat<I>

where I: Iterator<Item = B> + Clone, B: Borrow<Item<'a>>,

Formats the time with the specified formatting items. Otherwise it is the same as the ordinary format method.

The Iterator of items should be Cloneable, since the resulting DelayedFormat value may be formatted multiple times.

Example

use chrono::format::strftime::StrftimeItems;
use chrono::NaiveTime;

let fmt = StrftimeItems::new("%H:%M:%S");
let t = NaiveTime::from_hms_opt(23, 56, 4).unwrap();
assert_eq!(t.format_with_items(fmt.clone()).to_string(), "23:56:04");
assert_eq!(t.format("%H:%M:%S").to_string(), "23:56:04");

The resulting DelayedFormat can be formatted directly via the Display trait.

assert_eq!(format!("{}", t.format_with_items(fmt)), "23:56:04");

pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>>

Formats the time with the specified format string. See the format::strftime module on the supported escape sequences.

This returns a DelayedFormat, which gets converted to a string only when actual formatting happens. You may use the to_string method to get a String, or just feed it into print! and other formatting macros. (In this way it avoids the redundant memory allocation.)

A wrong format string does not issue an error immediately. Rather, converting or formatting the DelayedFormat fails. You are recommended to immediately use DelayedFormat for this reason.

Example

use chrono::NaiveTime;

let t = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!(t.format("%H:%M:%S").to_string(), "23:56:04");
assert_eq!(t.format("%H:%M:%S%.6f").to_string(), "23:56:04.012345");
assert_eq!(t.format("%-I:%M %p").to_string(), "11:56 PM");

The resulting DelayedFormat can be formatted directly via the Display trait.

assert_eq!(format!("{}", t.format("%H:%M:%S")), "23:56:04");
assert_eq!(format!("{}", t.format("%H:%M:%S%.6f")), "23:56:04.012345");
assert_eq!(format!("{}", t.format("%-I:%M %p")), "11:56 PM");

pub const MIN: Self = _

The earliest possible NaiveTime

Trait Implementations

impl Add<Duration> for NaiveTime

Add std::time::Duration to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

type Output = NaiveTime

The resulting type after applying the + operator.

fn add(self, rhs: Duration) -> NaiveTime

Performs the + operation.

impl Add<FixedOffset> for NaiveTime

Add FixedOffset to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

type Output = NaiveTime

The resulting type after applying the + operator.

fn add(self, rhs: FixedOffset) -> NaiveTime

Performs the + operation.

impl Add<TimeDelta> for NaiveTime

Add TimeDelta to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

As a part of Chrono’s leap second handling, the addition assumes that there is no leap second ever, except when the NaiveTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::zero(), from_hmsm(3, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(1).unwrap(), from_hmsm(3, 5, 8, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(-1).unwrap(), from_hmsm(3, 5, 6, 0));
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(60 + 4).unwrap(),
    from_hmsm(3, 6, 11, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(7 * 60 * 60 - 6 * 60).unwrap(),
    from_hmsm(9, 59, 7, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_milliseconds(80).unwrap(),
    from_hmsm(3, 5, 7, 80)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) + TimeDelta::try_milliseconds(280).unwrap(),
    from_hmsm(3, 5, 8, 230)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) + TimeDelta::try_milliseconds(-980).unwrap(),
    from_hmsm(3, 5, 6, 970)
);

The addition wraps around.

assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(22*60*60).unwrap(), from_hmsm(1, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(-8*60*60).unwrap(), from_hmsm(19, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_days(800).unwrap(), from_hmsm(3, 5, 7, 0));

Leap seconds are handled, but the addition assumes that it is the only leap second happened.

let leap = from_hmsm(3, 5, 59, 1_300);
assert_eq!(leap + TimeDelta::zero(), from_hmsm(3, 5, 59, 1_300));
assert_eq!(leap + TimeDelta::try_milliseconds(-500).unwrap(), from_hmsm(3, 5, 59, 800));
assert_eq!(leap + TimeDelta::try_milliseconds(500).unwrap(), from_hmsm(3, 5, 59, 1_800));
assert_eq!(leap + TimeDelta::try_milliseconds(800).unwrap(), from_hmsm(3, 6, 0, 100));
assert_eq!(leap + TimeDelta::try_seconds(10).unwrap(), from_hmsm(3, 6, 9, 300));
assert_eq!(leap + TimeDelta::try_seconds(-10).unwrap(), from_hmsm(3, 5, 50, 300));
assert_eq!(leap + TimeDelta::try_days(1).unwrap(), from_hmsm(3, 5, 59, 300));

type Output = NaiveTime

The resulting type after applying the + operator.

fn add(self, rhs: TimeDelta) -> NaiveTime

Performs the + operation.

impl AddAssign<Duration> for NaiveTime

Add-assign std::time::Duration to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

fn add_assign(&mut self, rhs: Duration)

Performs the += operation.

impl AddAssign<TimeDelta> for NaiveTime

Add-assign TimeDelta to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

fn add_assign(&mut self, rhs: TimeDelta)

Performs the += operation.

impl Clone for NaiveTime

fn clone(&self) -> NaiveTime

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NaiveTime

The Debug output of the naive time t is the same as t.format("%H:%M:%S%.f").

The string printed can be readily parsed via the parse method on str.

It should be noted that, for leap seconds not on the minute boundary, it may print a representation not distinguishable from non-leap seconds. This doesn’t matter in practice, since such leap seconds never happened. (By the time of the first leap second on 1972-06-30, every time zone offset around the world has standardized to the 5-minute alignment.)

Example

use chrono::NaiveTime;

assert_eq!(format!("{:?}", NaiveTime::from_hms_opt(23, 56, 4).unwrap()), "23:56:04");
assert_eq!(
    format!("{:?}", NaiveTime::from_hms_milli_opt(23, 56, 4, 12).unwrap()),
    "23:56:04.012"
);
assert_eq!(
    format!("{:?}", NaiveTime::from_hms_micro_opt(23, 56, 4, 1234).unwrap()),
    "23:56:04.001234"
);
assert_eq!(
    format!("{:?}", NaiveTime::from_hms_nano_opt(23, 56, 4, 123456).unwrap()),
    "23:56:04.000123456"
);

Leap seconds may also be used.

assert_eq!(
    format!("{:?}", NaiveTime::from_hms_milli_opt(6, 59, 59, 1_500).unwrap()),
    "06:59:60.500"
);

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for NaiveTime

The default value for a NaiveTime is midnight, 00:00:00 exactly.

Example

use chrono::NaiveTime;

let default_time = NaiveTime::default();
assert_eq!(default_time, NaiveTime::from_hms_opt(0, 0, 0).unwrap());

fn default() -> Self

Returns the “default value” for a type.

impl Display for NaiveTime

The Display output of the naive time t is the same as t.format("%H:%M:%S%.f").

The string printed can be readily parsed via the parse method on str.

It should be noted that, for leap seconds not on the minute boundary, it may print a representation not distinguishable from non-leap seconds. This doesn’t matter in practice, since such leap seconds never happened. (By the time of the first leap second on 1972-06-30, every time zone offset around the world has standardized to the 5-minute alignment.)

Example

use chrono::NaiveTime;

assert_eq!(format!("{}", NaiveTime::from_hms_opt(23, 56, 4).unwrap()), "23:56:04");
assert_eq!(
    format!("{}", NaiveTime::from_hms_milli_opt(23, 56, 4, 12).unwrap()),
    "23:56:04.012"
);
assert_eq!(
    format!("{}", NaiveTime::from_hms_micro_opt(23, 56, 4, 1234).unwrap()),
    "23:56:04.001234"
);
assert_eq!(
    format!("{}", NaiveTime::from_hms_nano_opt(23, 56, 4, 123456).unwrap()),
    "23:56:04.000123456"
);

Leap seconds may also be used.

assert_eq!(
    format!("{}", NaiveTime::from_hms_milli_opt(6, 59, 59, 1_500).unwrap()),
    "06:59:60.500"
);

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromStr for NaiveTime

Parsing a str into a NaiveTime uses the same format, %H:%M:%S%.f, as in Debug and Display.

Example

use chrono::NaiveTime;

let t = NaiveTime::from_hms_opt(23, 56, 4).unwrap();
assert_eq!("23:56:04".parse::<NaiveTime>(), Ok(t));

let t = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!("23:56:4.012345678".parse::<NaiveTime>(), Ok(t));

let t = NaiveTime::from_hms_nano_opt(23, 59, 59, 1_234_567_890).unwrap(); // leap second
assert_eq!("23:59:60.23456789".parse::<NaiveTime>(), Ok(t));

// Seconds are optional
let t = NaiveTime::from_hms_opt(23, 56, 0).unwrap();
assert_eq!("23:56".parse::<NaiveTime>(), Ok(t));

assert!("foo".parse::<NaiveTime>().is_err());

type Err = ParseError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> ParseResult<NaiveTime>

Parses a string s to return a value of this type.

impl Hash for NaiveTime

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for NaiveTime

fn cmp(&self, other: &NaiveTime) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for NaiveTime

fn eq(&self, other: &NaiveTime) -> bool

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

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for NaiveTime

fn partial_cmp(&self, other: &NaiveTime) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

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

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

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

fn ge(&self, other: &Rhs) -> bool

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

impl Sub<Duration> for NaiveTime

Subtract std::time::Duration from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days.

type Output = NaiveTime

The resulting type after applying the - operator.

fn sub(self, rhs: Duration) -> NaiveTime

Performs the - operation.

impl Sub<FixedOffset> for NaiveTime

Subtract FixedOffset from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days.

type Output = NaiveTime

The resulting type after applying the - operator.

fn sub(self, rhs: FixedOffset) -> NaiveTime

Performs the - operation.

impl Sub<TimeDelta> for NaiveTime

Subtract TimeDelta from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days. This is the same as addition with a negated TimeDelta.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when the NaiveTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::zero(), from_hmsm(3, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(1).unwrap(), from_hmsm(3, 5, 6, 0));
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(60 + 5).unwrap(),
    from_hmsm(3, 4, 2, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(2 * 60 * 60 + 6 * 60).unwrap(),
    from_hmsm(0, 59, 7, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) - TimeDelta::try_milliseconds(80).unwrap(),
    from_hmsm(3, 5, 6, 920)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) - TimeDelta::try_milliseconds(280).unwrap(),
    from_hmsm(3, 5, 7, 670)
);

The subtraction wraps around.

assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_seconds(8*60*60).unwrap(), from_hmsm(19, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) - TimeDelta::try_days(800).unwrap(), from_hmsm(3, 5, 7, 0));

Leap seconds are handled, but the subtraction assumes that it is the only leap second happened.

let leap = from_hmsm(3, 5, 59, 1_300);
assert_eq!(leap - TimeDelta::zero(), from_hmsm(3, 5, 59, 1_300));
assert_eq!(leap - TimeDelta::try_milliseconds(200).unwrap(), from_hmsm(3, 5, 59, 1_100));
assert_eq!(leap - TimeDelta::try_milliseconds(500).unwrap(), from_hmsm(3, 5, 59, 800));
assert_eq!(leap - TimeDelta::try_seconds(60).unwrap(), from_hmsm(3, 5, 0, 300));
assert_eq!(leap - TimeDelta::try_days(1).unwrap(), from_hmsm(3, 6, 0, 300));

type Output = NaiveTime

The resulting type after applying the - operator.

fn sub(self, rhs: TimeDelta) -> NaiveTime

Performs the - operation.

impl Sub for NaiveTime

Subtracts another NaiveTime from the current time. Returns a TimeDelta within +/- 1 day. This does not overflow or underflow at all.

As a part of Chrono’s leap second handling, the subtraction assumes that there is no leap second ever, except when any of the NaiveTimes themselves represents a leap second in which case the assumption becomes that there are exactly one (or two) leap second(s) ever.

The implementation is a wrapper around NaiveTime::signed_duration_since.

Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 7, 900), TimeDelta::zero());
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 7, 875),
    TimeDelta::try_milliseconds(25).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 6, 925),
    TimeDelta::try_milliseconds(975).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 5, 0, 900),
    TimeDelta::try_seconds(7).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(3, 0, 7, 900),
    TimeDelta::try_seconds(5 * 60).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(0, 5, 7, 900),
    TimeDelta::try_seconds(3 * 3600).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(4, 5, 7, 900),
    TimeDelta::try_seconds(-3600).unwrap()
);
assert_eq!(
    from_hmsm(3, 5, 7, 900) - from_hmsm(2, 4, 6, 800),
    TimeDelta::try_seconds(3600 + 60 + 1).unwrap() + TimeDelta::try_milliseconds(100).unwrap()
);

Leap seconds are handled, but the subtraction assumes that there were no other leap seconds happened.

assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(3, 0, 59, 0), TimeDelta::try_seconds(1).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_500) - from_hmsm(3, 0, 59, 0),
           TimeDelta::try_milliseconds(1500).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(3, 0, 0, 0), TimeDelta::try_seconds(60).unwrap());
assert_eq!(from_hmsm(3, 0, 0, 0) - from_hmsm(2, 59, 59, 1_000), TimeDelta::try_seconds(1).unwrap());
assert_eq!(from_hmsm(3, 0, 59, 1_000) - from_hmsm(2, 59, 59, 1_000),
           TimeDelta::try_seconds(61).unwrap());

type Output = TimeDelta

The resulting type after applying the - operator.

fn sub(self, rhs: NaiveTime) -> TimeDelta

Performs the - operation.

impl SubAssign<Duration> for NaiveTime

Subtract-assign std::time::Duration from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days.

fn sub_assign(&mut self, rhs: Duration)

Performs the -= operation.

impl SubAssign<TimeDelta> for NaiveTime

Subtract-assign TimeDelta from NaiveTime.

This wraps around and never overflows or underflows. In particular the subtraction ignores integral number of days.

fn sub_assign(&mut self, rhs: TimeDelta)

Performs the -= operation.

impl Timelike for NaiveTime

fn hour(&self) -> u32

Returns the hour number from 0 to 23.

Example

use chrono::{NaiveTime, Timelike};

assert_eq!(NaiveTime::from_hms_opt(0, 0, 0).unwrap().hour(), 0);
assert_eq!(NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap().hour(), 23);

fn minute(&self) -> u32

Returns the minute number from 0 to 59.

Example

use chrono::{NaiveTime, Timelike};

assert_eq!(NaiveTime::from_hms_opt(0, 0, 0).unwrap().minute(), 0);
assert_eq!(NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap().minute(), 56);

fn second(&self) -> u32

Returns the second number from 0 to 59.

Example

use chrono::{NaiveTime, Timelike};

assert_eq!(NaiveTime::from_hms_opt(0, 0, 0).unwrap().second(), 0);
assert_eq!(NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap().second(), 4);

This method never returns 60 even when it is a leap second. (Why?) Use the proper formatting method to get a human-readable representation.

let leap = NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap();
assert_eq!(leap.second(), 59);
assert_eq!(leap.format("%H:%M:%S").to_string(), "23:59:60");

fn nanosecond(&self) -> u32

Returns the number of nanoseconds since the whole non-leap second. The range from 1,000,000,000 to 1,999,999,999 represents the leap second.

Example

use chrono::{NaiveTime, Timelike};

assert_eq!(NaiveTime::from_hms_opt(0, 0, 0).unwrap().nanosecond(), 0);
assert_eq!(
    NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap().nanosecond(),
    12_345_678
);

Leap seconds may have seemingly out-of-range return values. You can reduce the range with time.nanosecond() % 1_000_000_000, or use the proper formatting method to get a human-readable representation.

let leap = NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap();
assert_eq!(leap.nanosecond(), 1_000_000_000);
assert_eq!(leap.format("%H:%M:%S%.9f").to_string(), "23:59:60.000000000");

fn with_hour(&self, hour: u32) -> Option<NaiveTime>

Makes a new NaiveTime with the hour number changed.

Errors

Returns None if the value for hour is invalid.

Example

use chrono::{NaiveTime, Timelike};

let dt = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!(dt.with_hour(7), Some(NaiveTime::from_hms_nano_opt(7, 56, 4, 12_345_678).unwrap()));
assert_eq!(dt.with_hour(24), None);

fn with_minute(&self, min: u32) -> Option<NaiveTime>

Makes a new NaiveTime with the minute number changed.

Errors

Returns None if the value for minute is invalid.

Example

use chrono::{NaiveTime, Timelike};

let dt = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!(
    dt.with_minute(45),
    Some(NaiveTime::from_hms_nano_opt(23, 45, 4, 12_345_678).unwrap())
);
assert_eq!(dt.with_minute(60), None);

fn with_second(&self, sec: u32) -> Option<NaiveTime>

Makes a new NaiveTime with the second number changed.

As with the second method, the input range is restricted to 0 through 59.

Errors

Returns None if the value for second is invalid.

Example

use chrono::{NaiveTime, Timelike};

let dt = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!(
    dt.with_second(17),
    Some(NaiveTime::from_hms_nano_opt(23, 56, 17, 12_345_678).unwrap())
);
assert_eq!(dt.with_second(60), None);

fn with_nanosecond(&self, nano: u32) -> Option<NaiveTime>

Makes a new NaiveTime with nanoseconds since the whole non-leap second changed.

As with the nanosecond method, the input range can exceed 1,000,000,000 for leap seconds.

Errors

Returns None if nanosecond >= 2,000,000,000.

Example

use chrono::{NaiveTime, Timelike};

let dt = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!(
    dt.with_nanosecond(333_333_333),
    Some(NaiveTime::from_hms_nano_opt(23, 56, 4, 333_333_333).unwrap())
);
assert_eq!(dt.with_nanosecond(2_000_000_000), None);

Leap seconds can theoretically follow any whole second. The following would be a proper leap second at the time zone offset of UTC-00:03:57 (there are several historical examples comparable to this “non-sense” offset), and therefore is allowed.

let dt = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
let strange_leap_second = dt.with_nanosecond(1_333_333_333).unwrap();
assert_eq!(strange_leap_second.nanosecond(), 1_333_333_333);

fn num_seconds_from_midnight(&self) -> u32

Returns the number of non-leap seconds past the last midnight.

Example

use chrono::{NaiveTime, Timelike};

assert_eq!(NaiveTime::from_hms_opt(1, 2, 3).unwrap().num_seconds_from_midnight(), 3723);
assert_eq!(
    NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap().num_seconds_from_midnight(),
    86164
);
assert_eq!(
    NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap().num_seconds_from_midnight(),
    86399
);

fn hour12(&self) -> (bool, u32)

Returns the hour number from 1 to 12 with a boolean flag, which is false for AM and true for PM.

impl Copy for NaiveTime

impl Eq for NaiveTime

impl StructuralPartialEq for NaiveTime