1 #![stable(feature = "duration_core", since = "1.25.0")]
3 //! Temporal quantification.
7 //! There are multiple ways to create a new [`Duration`]:
10 //! # use std::time::Duration;
11 //! let five_seconds = Duration::from_secs(5);
12 //! assert_eq!(five_seconds, Duration::from_millis(5_000));
13 //! assert_eq!(five_seconds, Duration::from_micros(5_000_000));
14 //! assert_eq!(five_seconds, Duration::from_nanos(5_000_000_000));
16 //! let ten_seconds = Duration::from_secs(10);
17 //! let seven_nanos = Duration::from_nanos(7);
18 //! let total = ten_seconds + seven_nanos;
19 //! assert_eq!(total, Duration::new(10, 7));
24 use crate::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
26 const NANOS_PER_SEC: u32 = 1_000_000_000;
27 const NANOS_PER_MILLI: u32 = 1_000_000;
28 const NANOS_PER_MICRO: u32 = 1_000;
29 const MILLIS_PER_SEC: u64 = 1_000;
30 const MICROS_PER_SEC: u64 = 1_000_000;
32 /// A `Duration` type to represent a span of time, typically used for system
35 /// Each `Duration` is composed of a whole number of seconds and a fractional part
36 /// represented in nanoseconds. If the underlying system does not support
37 /// nanosecond-level precision, APIs binding a system timeout will typically round up
38 /// the number of nanoseconds.
40 /// [`Duration`]s implement many common traits, including [`Add`], [`Sub`], and other
41 /// [`ops`] traits. It implements [`Default`] by returning a zero-length `Duration`.
43 /// [`ops`]: crate::ops
48 /// use std::time::Duration;
50 /// let five_seconds = Duration::new(5, 0);
51 /// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
53 /// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
54 /// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
56 /// let ten_millis = Duration::from_millis(10);
59 /// # Formatting `Duration` values
61 /// `Duration` intentionally does not have a `Display` impl, as there are a
62 /// variety of ways to format spans of time for human readability. `Duration`
63 /// provides a `Debug` impl that shows the full precision of the value.
65 /// The `Debug` output uses the non-ASCII "µs" suffix for microseconds. If your
66 /// program output may appear in contexts that cannot rely on full Unicode
67 /// compatibility, you may wish to format `Duration` objects yourself or use a
69 #[stable(feature = "duration", since = "1.3.0")]
70 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
71 #[cfg_attr(not(test), rustc_diagnostic_item = "Duration")]
74 nanos: u32, // Always 0 <= nanos < NANOS_PER_SEC
78 /// The duration of one second.
83 /// #![feature(duration_constants)]
84 /// use std::time::Duration;
86 /// assert_eq!(Duration::SECOND, Duration::from_secs(1));
88 #[unstable(feature = "duration_constants", issue = "57391")]
89 pub const SECOND: Duration = Duration::from_secs(1);
91 /// The duration of one millisecond.
96 /// #![feature(duration_constants)]
97 /// use std::time::Duration;
99 /// assert_eq!(Duration::MILLISECOND, Duration::from_millis(1));
101 #[unstable(feature = "duration_constants", issue = "57391")]
102 pub const MILLISECOND: Duration = Duration::from_millis(1);
104 /// The duration of one microsecond.
109 /// #![feature(duration_constants)]
110 /// use std::time::Duration;
112 /// assert_eq!(Duration::MICROSECOND, Duration::from_micros(1));
114 #[unstable(feature = "duration_constants", issue = "57391")]
115 pub const MICROSECOND: Duration = Duration::from_micros(1);
117 /// The duration of one nanosecond.
122 /// #![feature(duration_constants)]
123 /// use std::time::Duration;
125 /// assert_eq!(Duration::NANOSECOND, Duration::from_nanos(1));
127 #[unstable(feature = "duration_constants", issue = "57391")]
128 pub const NANOSECOND: Duration = Duration::from_nanos(1);
130 /// A duration of zero time.
135 /// use std::time::Duration;
137 /// let duration = Duration::ZERO;
138 /// assert!(duration.is_zero());
139 /// assert_eq!(duration.as_nanos(), 0);
141 #[stable(feature = "duration_zero", since = "1.53.0")]
142 pub const ZERO: Duration = Duration::from_nanos(0);
144 /// The maximum duration.
146 /// May vary by platform as necessary. Must be able to contain the difference between
147 /// two instances of [`Instant`] or two instances of [`SystemTime`].
148 /// This constraint gives it a value of about 584,942,417,355 years in practice,
149 /// which is currently used on all platforms.
154 /// use std::time::Duration;
156 /// assert_eq!(Duration::MAX, Duration::new(u64::MAX, 1_000_000_000 - 1));
158 /// [`Instant`]: ../../std/time/struct.Instant.html
159 /// [`SystemTime`]: ../../std/time/struct.SystemTime.html
160 #[stable(feature = "duration_saturating_ops", since = "1.53.0")]
161 pub const MAX: Duration = Duration::new(u64::MAX, NANOS_PER_SEC - 1);
163 /// Creates a new `Duration` from the specified number of whole seconds and
164 /// additional nanoseconds.
166 /// If the number of nanoseconds is greater than 1 billion (the number of
167 /// nanoseconds in a second), then it will carry over into the seconds provided.
171 /// This constructor will panic if the carry from the nanoseconds overflows
172 /// the seconds counter.
177 /// use std::time::Duration;
179 /// let five_seconds = Duration::new(5, 0);
181 #[stable(feature = "duration", since = "1.3.0")]
184 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
185 pub const fn new(secs: u64, nanos: u32) -> Duration {
186 let secs = match secs.checked_add((nanos / NANOS_PER_SEC) as u64) {
188 None => panic!("overflow in Duration::new"),
190 let nanos = nanos % NANOS_PER_SEC;
191 Duration { secs, nanos }
194 /// Creates a new `Duration` from the specified number of whole seconds.
199 /// use std::time::Duration;
201 /// let duration = Duration::from_secs(5);
203 /// assert_eq!(5, duration.as_secs());
204 /// assert_eq!(0, duration.subsec_nanos());
206 #[stable(feature = "duration", since = "1.3.0")]
209 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
210 pub const fn from_secs(secs: u64) -> Duration {
211 Duration { secs, nanos: 0 }
214 /// Creates a new `Duration` from the specified number of milliseconds.
219 /// use std::time::Duration;
221 /// let duration = Duration::from_millis(2569);
223 /// assert_eq!(2, duration.as_secs());
224 /// assert_eq!(569_000_000, duration.subsec_nanos());
226 #[stable(feature = "duration", since = "1.3.0")]
229 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
230 pub const fn from_millis(millis: u64) -> Duration {
232 secs: millis / MILLIS_PER_SEC,
233 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
237 /// Creates a new `Duration` from the specified number of microseconds.
242 /// use std::time::Duration;
244 /// let duration = Duration::from_micros(1_000_002);
246 /// assert_eq!(1, duration.as_secs());
247 /// assert_eq!(2000, duration.subsec_nanos());
249 #[stable(feature = "duration_from_micros", since = "1.27.0")]
252 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
253 pub const fn from_micros(micros: u64) -> Duration {
255 secs: micros / MICROS_PER_SEC,
256 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
260 /// Creates a new `Duration` from the specified number of nanoseconds.
265 /// use std::time::Duration;
267 /// let duration = Duration::from_nanos(1_000_000_123);
269 /// assert_eq!(1, duration.as_secs());
270 /// assert_eq!(123, duration.subsec_nanos());
272 #[stable(feature = "duration_extras", since = "1.27.0")]
275 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
276 pub const fn from_nanos(nanos: u64) -> Duration {
278 secs: nanos / (NANOS_PER_SEC as u64),
279 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
283 /// Returns true if this `Duration` spans no time.
288 /// use std::time::Duration;
290 /// assert!(Duration::ZERO.is_zero());
291 /// assert!(Duration::new(0, 0).is_zero());
292 /// assert!(Duration::from_nanos(0).is_zero());
293 /// assert!(Duration::from_secs(0).is_zero());
295 /// assert!(!Duration::new(1, 1).is_zero());
296 /// assert!(!Duration::from_nanos(1).is_zero());
297 /// assert!(!Duration::from_secs(1).is_zero());
300 #[stable(feature = "duration_zero", since = "1.53.0")]
301 #[rustc_const_stable(feature = "duration_zero", since = "1.53.0")]
303 pub const fn is_zero(&self) -> bool {
304 self.secs == 0 && self.nanos == 0
307 /// Returns the number of _whole_ seconds contained by this `Duration`.
309 /// The returned value does not include the fractional (nanosecond) part of the
310 /// duration, which can be obtained using [`subsec_nanos`].
315 /// use std::time::Duration;
317 /// let duration = Duration::new(5, 730023852);
318 /// assert_eq!(duration.as_secs(), 5);
321 /// To determine the total number of seconds represented by the `Duration`
322 /// including the fractional part, use [`as_secs_f64`] or [`as_secs_f32`]
324 /// [`as_secs_f64`]: Duration::as_secs_f64
325 /// [`as_secs_f32`]: Duration::as_secs_f32
326 /// [`subsec_nanos`]: Duration::subsec_nanos
327 #[stable(feature = "duration", since = "1.3.0")]
328 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
331 pub const fn as_secs(&self) -> u64 {
335 /// Returns the fractional part of this `Duration`, in whole milliseconds.
337 /// This method does **not** return the length of the duration when
338 /// represented by milliseconds. The returned number always represents a
339 /// fractional portion of a second (i.e., it is less than one thousand).
344 /// use std::time::Duration;
346 /// let duration = Duration::from_millis(5432);
347 /// assert_eq!(duration.as_secs(), 5);
348 /// assert_eq!(duration.subsec_millis(), 432);
350 #[stable(feature = "duration_extras", since = "1.27.0")]
351 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
354 pub const fn subsec_millis(&self) -> u32 {
355 self.nanos / NANOS_PER_MILLI
358 /// Returns the fractional part of this `Duration`, in whole microseconds.
360 /// This method does **not** return the length of the duration when
361 /// represented by microseconds. The returned number always represents a
362 /// fractional portion of a second (i.e., it is less than one million).
367 /// use std::time::Duration;
369 /// let duration = Duration::from_micros(1_234_567);
370 /// assert_eq!(duration.as_secs(), 1);
371 /// assert_eq!(duration.subsec_micros(), 234_567);
373 #[stable(feature = "duration_extras", since = "1.27.0")]
374 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
377 pub const fn subsec_micros(&self) -> u32 {
378 self.nanos / NANOS_PER_MICRO
381 /// Returns the fractional part of this `Duration`, in nanoseconds.
383 /// This method does **not** return the length of the duration when
384 /// represented by nanoseconds. The returned number always represents a
385 /// fractional portion of a second (i.e., it is less than one billion).
390 /// use std::time::Duration;
392 /// let duration = Duration::from_millis(5010);
393 /// assert_eq!(duration.as_secs(), 5);
394 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
396 #[stable(feature = "duration", since = "1.3.0")]
397 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
400 pub const fn subsec_nanos(&self) -> u32 {
404 /// Returns the total number of whole milliseconds contained by this `Duration`.
409 /// use std::time::Duration;
411 /// let duration = Duration::new(5, 730023852);
412 /// assert_eq!(duration.as_millis(), 5730);
414 #[stable(feature = "duration_as_u128", since = "1.33.0")]
415 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
418 pub const fn as_millis(&self) -> u128 {
419 self.secs as u128 * MILLIS_PER_SEC as u128 + (self.nanos / NANOS_PER_MILLI) as u128
422 /// Returns the total number of whole microseconds contained by this `Duration`.
427 /// use std::time::Duration;
429 /// let duration = Duration::new(5, 730023852);
430 /// assert_eq!(duration.as_micros(), 5730023);
432 #[stable(feature = "duration_as_u128", since = "1.33.0")]
433 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
436 pub const fn as_micros(&self) -> u128 {
437 self.secs as u128 * MICROS_PER_SEC as u128 + (self.nanos / NANOS_PER_MICRO) as u128
440 /// Returns the total number of nanoseconds contained by this `Duration`.
445 /// use std::time::Duration;
447 /// let duration = Duration::new(5, 730023852);
448 /// assert_eq!(duration.as_nanos(), 5730023852);
450 #[stable(feature = "duration_as_u128", since = "1.33.0")]
451 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
454 pub const fn as_nanos(&self) -> u128 {
455 self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos as u128
458 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
459 /// if overflow occurred.
466 /// use std::time::Duration;
468 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
469 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(u64::MAX, 0)), None);
471 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
472 #[must_use = "this returns the result of the operation, \
473 without modifying the original"]
475 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
476 pub const fn checked_add(self, rhs: Duration) -> Option<Duration> {
477 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
478 let mut nanos = self.nanos + rhs.nanos;
479 if nanos >= NANOS_PER_SEC {
480 nanos -= NANOS_PER_SEC;
481 if let Some(new_secs) = secs.checked_add(1) {
487 debug_assert!(nanos < NANOS_PER_SEC);
488 Some(Duration { secs, nanos })
494 /// Saturating `Duration` addition. Computes `self + other`, returning [`Duration::MAX`]
495 /// if overflow occurred.
500 /// #![feature(duration_constants)]
501 /// use std::time::Duration;
503 /// assert_eq!(Duration::new(0, 0).saturating_add(Duration::new(0, 1)), Duration::new(0, 1));
504 /// assert_eq!(Duration::new(1, 0).saturating_add(Duration::new(u64::MAX, 0)), Duration::MAX);
506 #[stable(feature = "duration_saturating_ops", since = "1.53.0")]
507 #[must_use = "this returns the result of the operation, \
508 without modifying the original"]
510 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
511 pub const fn saturating_add(self, rhs: Duration) -> Duration {
512 match self.checked_add(rhs) {
514 None => Duration::MAX,
518 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
519 /// if the result would be negative or if overflow occurred.
526 /// use std::time::Duration;
528 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
529 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
531 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
532 #[must_use = "this returns the result of the operation, \
533 without modifying the original"]
535 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
536 pub const fn checked_sub(self, rhs: Duration) -> Option<Duration> {
537 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
538 let nanos = if self.nanos >= rhs.nanos {
539 self.nanos - rhs.nanos
540 } else if let Some(sub_secs) = secs.checked_sub(1) {
542 self.nanos + NANOS_PER_SEC - rhs.nanos
546 debug_assert!(nanos < NANOS_PER_SEC);
547 Some(Duration { secs, nanos })
553 /// Saturating `Duration` subtraction. Computes `self - other`, returning [`Duration::ZERO`]
554 /// if the result would be negative or if overflow occurred.
559 /// use std::time::Duration;
561 /// assert_eq!(Duration::new(0, 1).saturating_sub(Duration::new(0, 0)), Duration::new(0, 1));
562 /// assert_eq!(Duration::new(0, 0).saturating_sub(Duration::new(0, 1)), Duration::ZERO);
564 #[stable(feature = "duration_saturating_ops", since = "1.53.0")]
565 #[must_use = "this returns the result of the operation, \
566 without modifying the original"]
568 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
569 pub const fn saturating_sub(self, rhs: Duration) -> Duration {
570 match self.checked_sub(rhs) {
572 None => Duration::ZERO,
576 /// Checked `Duration` multiplication. Computes `self * other`, returning
577 /// [`None`] if overflow occurred.
584 /// use std::time::Duration;
586 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
587 /// assert_eq!(Duration::new(u64::MAX - 1, 0).checked_mul(2), None);
589 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
590 #[must_use = "this returns the result of the operation, \
591 without modifying the original"]
593 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
594 pub const fn checked_mul(self, rhs: u32) -> Option<Duration> {
595 // Multiply nanoseconds as u64, because it cannot overflow that way.
596 let total_nanos = self.nanos as u64 * rhs as u64;
597 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
598 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
599 if let Some(s) = self.secs.checked_mul(rhs as u64) {
600 if let Some(secs) = s.checked_add(extra_secs) {
601 debug_assert!(nanos < NANOS_PER_SEC);
602 return Some(Duration { secs, nanos });
608 /// Saturating `Duration` multiplication. Computes `self * other`, returning
609 /// [`Duration::MAX`] if overflow occurred.
614 /// #![feature(duration_constants)]
615 /// use std::time::Duration;
617 /// assert_eq!(Duration::new(0, 500_000_001).saturating_mul(2), Duration::new(1, 2));
618 /// assert_eq!(Duration::new(u64::MAX - 1, 0).saturating_mul(2), Duration::MAX);
620 #[stable(feature = "duration_saturating_ops", since = "1.53.0")]
621 #[must_use = "this returns the result of the operation, \
622 without modifying the original"]
624 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
625 pub const fn saturating_mul(self, rhs: u32) -> Duration {
626 match self.checked_mul(rhs) {
628 None => Duration::MAX,
632 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
640 /// use std::time::Duration;
642 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
643 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
644 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
646 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
647 #[must_use = "this returns the result of the operation, \
648 without modifying the original"]
650 #[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
651 pub const fn checked_div(self, rhs: u32) -> Option<Duration> {
653 let secs = self.secs / (rhs as u64);
654 let carry = self.secs - secs * (rhs as u64);
655 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
656 let nanos = self.nanos / rhs + (extra_nanos as u32);
657 debug_assert!(nanos < NANOS_PER_SEC);
658 Some(Duration { secs, nanos })
664 /// Returns the number of seconds contained by this `Duration` as `f64`.
666 /// The returned value does include the fractional (nanosecond) part of the duration.
670 /// use std::time::Duration;
672 /// let dur = Duration::new(2, 700_000_000);
673 /// assert_eq!(dur.as_secs_f64(), 2.7);
675 #[stable(feature = "duration_float", since = "1.38.0")]
678 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
679 pub const fn as_secs_f64(&self) -> f64 {
680 (self.secs as f64) + (self.nanos as f64) / (NANOS_PER_SEC as f64)
683 /// Returns the number of seconds contained by this `Duration` as `f32`.
685 /// The returned value does include the fractional (nanosecond) part of the duration.
689 /// use std::time::Duration;
691 /// let dur = Duration::new(2, 700_000_000);
692 /// assert_eq!(dur.as_secs_f32(), 2.7);
694 #[stable(feature = "duration_float", since = "1.38.0")]
697 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
698 pub const fn as_secs_f32(&self) -> f32 {
699 (self.secs as f32) + (self.nanos as f32) / (NANOS_PER_SEC as f32)
702 /// Creates a new `Duration` from the specified number of seconds represented
706 /// This constructor will panic if `secs` is negative, overflows `Duration` or not finite.
710 /// use std::time::Duration;
712 /// let res = Duration::from_secs_f64(0.0);
713 /// assert_eq!(res, Duration::new(0, 0));
714 /// let res = Duration::from_secs_f64(1e-20);
715 /// assert_eq!(res, Duration::new(0, 0));
716 /// let res = Duration::from_secs_f64(4.2e-7);
717 /// assert_eq!(res, Duration::new(0, 420));
718 /// let res = Duration::from_secs_f64(2.7);
719 /// assert_eq!(res, Duration::new(2, 700_000_000));
720 /// let res = Duration::from_secs_f64(3e10);
721 /// assert_eq!(res, Duration::new(30_000_000_000, 0));
722 /// // subnormal float
723 /// let res = Duration::from_secs_f64(f64::from_bits(1));
724 /// assert_eq!(res, Duration::new(0, 0));
725 /// // conversion uses rounding
726 /// let res = Duration::from_secs_f64(0.999e-9);
727 /// assert_eq!(res, Duration::new(0, 1));
729 #[stable(feature = "duration_float", since = "1.38.0")]
732 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
733 pub const fn from_secs_f64(secs: f64) -> Duration {
734 match Duration::try_from_secs_f64(secs) {
736 Err(e) => panic!("{}", e.description()),
740 /// Creates a new `Duration` from the specified number of seconds represented
744 /// This constructor will panic if `secs` is negative, overflows `Duration` or not finite.
748 /// use std::time::Duration;
750 /// let res = Duration::from_secs_f32(0.0);
751 /// assert_eq!(res, Duration::new(0, 0));
752 /// let res = Duration::from_secs_f32(1e-20);
753 /// assert_eq!(res, Duration::new(0, 0));
754 /// let res = Duration::from_secs_f32(4.2e-7);
755 /// assert_eq!(res, Duration::new(0, 420));
756 /// let res = Duration::from_secs_f32(2.7);
757 /// assert_eq!(res, Duration::new(2, 700_000_048));
758 /// let res = Duration::from_secs_f32(3e10);
759 /// assert_eq!(res, Duration::new(30_000_001_024, 0));
760 /// // subnormal float
761 /// let res = Duration::from_secs_f32(f32::from_bits(1));
762 /// assert_eq!(res, Duration::new(0, 0));
763 /// // conversion uses rounding
764 /// let res = Duration::from_secs_f32(0.999e-9);
765 /// assert_eq!(res, Duration::new(0, 1));
767 #[stable(feature = "duration_float", since = "1.38.0")]
770 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
771 pub const fn from_secs_f32(secs: f32) -> Duration {
772 match Duration::try_from_secs_f32(secs) {
774 Err(e) => panic!("{}", e.description()),
778 /// Multiplies `Duration` by `f64`.
781 /// This method will panic if result is negative, overflows `Duration` or not finite.
785 /// use std::time::Duration;
787 /// let dur = Duration::new(2, 700_000_000);
788 /// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
789 /// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
791 #[stable(feature = "duration_float", since = "1.38.0")]
792 #[must_use = "this returns the result of the operation, \
793 without modifying the original"]
795 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
796 pub const fn mul_f64(self, rhs: f64) -> Duration {
797 Duration::from_secs_f64(rhs * self.as_secs_f64())
800 /// Multiplies `Duration` by `f32`.
803 /// This method will panic if result is negative, overflows `Duration` or not finite.
807 /// use std::time::Duration;
809 /// let dur = Duration::new(2, 700_000_000);
810 /// assert_eq!(dur.mul_f32(3.14), Duration::new(8, 478_000_641));
811 /// assert_eq!(dur.mul_f32(3.14e5), Duration::new(847800, 0));
813 #[stable(feature = "duration_float", since = "1.38.0")]
814 #[must_use = "this returns the result of the operation, \
815 without modifying the original"]
817 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
818 pub const fn mul_f32(self, rhs: f32) -> Duration {
819 Duration::from_secs_f32(rhs * self.as_secs_f32())
822 /// Divide `Duration` by `f64`.
825 /// This method will panic if result is negative, overflows `Duration` or not finite.
829 /// use std::time::Duration;
831 /// let dur = Duration::new(2, 700_000_000);
832 /// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
833 /// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_599));
835 #[stable(feature = "duration_float", since = "1.38.0")]
836 #[must_use = "this returns the result of the operation, \
837 without modifying the original"]
839 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
840 pub const fn div_f64(self, rhs: f64) -> Duration {
841 Duration::from_secs_f64(self.as_secs_f64() / rhs)
844 /// Divide `Duration` by `f32`.
847 /// This method will panic if result is negative, overflows `Duration` or not finite.
851 /// use std::time::Duration;
853 /// let dur = Duration::new(2, 700_000_000);
854 /// // note that due to rounding errors result is slightly
855 /// // different from 0.859_872_611
856 /// assert_eq!(dur.div_f32(3.14), Duration::new(0, 859_872_580));
857 /// assert_eq!(dur.div_f32(3.14e5), Duration::new(0, 8_599));
859 #[stable(feature = "duration_float", since = "1.38.0")]
860 #[must_use = "this returns the result of the operation, \
861 without modifying the original"]
863 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
864 pub const fn div_f32(self, rhs: f32) -> Duration {
865 Duration::from_secs_f32(self.as_secs_f32() / rhs)
868 /// Divide `Duration` by `Duration` and return `f64`.
872 /// #![feature(div_duration)]
873 /// use std::time::Duration;
875 /// let dur1 = Duration::new(2, 700_000_000);
876 /// let dur2 = Duration::new(5, 400_000_000);
877 /// assert_eq!(dur1.div_duration_f64(dur2), 0.5);
879 #[unstable(feature = "div_duration", issue = "63139")]
880 #[must_use = "this returns the result of the operation, \
881 without modifying the original"]
883 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
884 pub const fn div_duration_f64(self, rhs: Duration) -> f64 {
885 self.as_secs_f64() / rhs.as_secs_f64()
888 /// Divide `Duration` by `Duration` and return `f32`.
892 /// #![feature(div_duration)]
893 /// use std::time::Duration;
895 /// let dur1 = Duration::new(2, 700_000_000);
896 /// let dur2 = Duration::new(5, 400_000_000);
897 /// assert_eq!(dur1.div_duration_f32(dur2), 0.5);
899 #[unstable(feature = "div_duration", issue = "63139")]
900 #[must_use = "this returns the result of the operation, \
901 without modifying the original"]
903 #[rustc_const_unstable(feature = "duration_consts_float", issue = "72440")]
904 pub const fn div_duration_f32(self, rhs: Duration) -> f32 {
905 self.as_secs_f32() / rhs.as_secs_f32()
909 #[stable(feature = "duration", since = "1.3.0")]
910 impl Add for Duration {
911 type Output = Duration;
913 fn add(self, rhs: Duration) -> Duration {
914 self.checked_add(rhs).expect("overflow when adding durations")
918 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
919 impl AddAssign for Duration {
920 fn add_assign(&mut self, rhs: Duration) {
925 #[stable(feature = "duration", since = "1.3.0")]
926 impl Sub for Duration {
927 type Output = Duration;
929 fn sub(self, rhs: Duration) -> Duration {
930 self.checked_sub(rhs).expect("overflow when subtracting durations")
934 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
935 impl SubAssign for Duration {
936 fn sub_assign(&mut self, rhs: Duration) {
941 #[stable(feature = "duration", since = "1.3.0")]
942 impl Mul<u32> for Duration {
943 type Output = Duration;
945 fn mul(self, rhs: u32) -> Duration {
946 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
950 #[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
951 impl Mul<Duration> for u32 {
952 type Output = Duration;
954 fn mul(self, rhs: Duration) -> Duration {
959 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
960 impl MulAssign<u32> for Duration {
961 fn mul_assign(&mut self, rhs: u32) {
966 #[stable(feature = "duration", since = "1.3.0")]
967 impl Div<u32> for Duration {
968 type Output = Duration;
970 fn div(self, rhs: u32) -> Duration {
971 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
975 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
976 impl DivAssign<u32> for Duration {
977 fn div_assign(&mut self, rhs: u32) {
982 macro_rules! sum_durations {
984 let mut total_secs: u64 = 0;
985 let mut total_nanos: u64 = 0;
989 total_secs.checked_add(entry.secs).expect("overflow in iter::sum over durations");
990 total_nanos = match total_nanos.checked_add(entry.nanos as u64) {
993 total_secs = total_secs
994 .checked_add(total_nanos / NANOS_PER_SEC as u64)
995 .expect("overflow in iter::sum over durations");
996 (total_nanos % NANOS_PER_SEC as u64) + entry.nanos as u64
1000 total_secs = total_secs
1001 .checked_add(total_nanos / NANOS_PER_SEC as u64)
1002 .expect("overflow in iter::sum over durations");
1003 total_nanos = total_nanos % NANOS_PER_SEC as u64;
1004 Duration { secs: total_secs, nanos: total_nanos as u32 }
1008 #[stable(feature = "duration_sum", since = "1.16.0")]
1009 impl Sum for Duration {
1010 fn sum<I: Iterator<Item = Duration>>(iter: I) -> Duration {
1011 sum_durations!(iter)
1015 #[stable(feature = "duration_sum", since = "1.16.0")]
1016 impl<'a> Sum<&'a Duration> for Duration {
1017 fn sum<I: Iterator<Item = &'a Duration>>(iter: I) -> Duration {
1018 sum_durations!(iter)
1022 #[stable(feature = "duration_debug_impl", since = "1.27.0")]
1023 impl fmt::Debug for Duration {
1024 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1025 /// Formats a floating point number in decimal notation.
1027 /// The number is given as the `integer_part` and a fractional part.
1028 /// The value of the fractional part is `fractional_part / divisor`. So
1029 /// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
1030 /// represents the number `3.012`. Trailing zeros are omitted.
1032 /// `divisor` must not be above 100_000_000. It also should be a power
1033 /// of 10, everything else doesn't make sense. `fractional_part` has
1034 /// to be less than `10 * divisor`!
1036 /// A prefix and postfix may be added. The whole thing is padded
1037 /// to the formatter's `width`, if specified.
1039 f: &mut fmt::Formatter<'_>,
1040 mut integer_part: u64,
1041 mut fractional_part: u32,
1046 // Encode the fractional part into a temporary buffer. The buffer
1047 // only need to hold 9 elements, because `fractional_part` has to
1048 // be smaller than 10^9. The buffer is prefilled with '0' digits
1049 // to simplify the code below.
1050 let mut buf = [b'0'; 9];
1052 // The next digit is written at this position
1055 // We keep writing digits into the buffer while there are non-zero
1056 // digits left and we haven't written enough digits yet.
1057 while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
1058 // Write new digit into the buffer
1059 buf[pos] = b'0' + (fractional_part / divisor) as u8;
1061 fractional_part %= divisor;
1066 // If a precision < 9 was specified, there may be some non-zero
1067 // digits left that weren't written into the buffer. In that case we
1068 // need to perform rounding to match the semantics of printing
1069 // normal floating point numbers. However, we only need to do work
1070 // when rounding up. This happens if the first digit of the
1071 // remaining ones is >= 5.
1072 if fractional_part > 0 && fractional_part >= divisor * 5 {
1073 // Round up the number contained in the buffer. We go through
1074 // the buffer backwards and keep track of the carry.
1075 let mut rev_pos = pos;
1076 let mut carry = true;
1077 while carry && rev_pos > 0 {
1080 // If the digit in the buffer is not '9', we just need to
1081 // increment it and can stop then (since we don't have a
1082 // carry anymore). Otherwise, we set it to '0' (overflow)
1084 if buf[rev_pos] < b'9' {
1088 buf[rev_pos] = b'0';
1092 // If we still have the carry bit set, that means that we set
1093 // the whole buffer to '0's and need to increment the integer
1100 // Determine the end of the buffer: if precision is set, we just
1101 // use as many digits from the buffer (capped to 9). If it isn't
1102 // set, we only use all digits up to the last non-zero one.
1103 let end = f.precision().map(|p| crate::cmp::min(p, 9)).unwrap_or(pos);
1105 // This closure emits the formatted duration without emitting any
1106 // padding (padding is calculated below).
1107 let emit_without_padding = |f: &mut fmt::Formatter<'_>| {
1108 write!(f, "{}{}", prefix, integer_part)?;
1110 // Write the decimal point and the fractional part (if any).
1112 // SAFETY: We are only writing ASCII digits into the buffer and
1113 // it was initialized with '0's, so it contains valid UTF8.
1114 let s = unsafe { crate::str::from_utf8_unchecked(&buf[..end]) };
1116 // If the user request a precision > 9, we pad '0's at the end.
1117 let w = f.precision().unwrap_or(pos);
1118 write!(f, ".{:0<width$}", s, width = w)?;
1121 write!(f, "{}", postfix)
1126 // No `width` specified. There's no need to calculate the
1127 // length of the output in this case, just emit it.
1128 emit_without_padding(f)
1130 Some(requested_w) => {
1131 // A `width` was specified. Calculate the actual width of
1132 // the output in order to calculate the required padding.
1133 // It consists of 4 parts:
1134 // 1. The prefix: is either "+" or "", so we can just use len().
1135 // 2. The postfix: can be "µs" so we have to count UTF8 characters.
1136 let mut actual_w = prefix.len() + postfix.chars().count();
1137 // 3. The integer part:
1138 if let Some(log) = integer_part.checked_ilog10() {
1139 // integer_part is > 0, so has length log10(x)+1
1140 actual_w += 1 + log as usize;
1142 // integer_part is 0, so has length 1.
1145 // 4. The fractional part (if any):
1147 let frac_part_w = f.precision().unwrap_or(pos);
1148 actual_w += 1 + frac_part_w;
1151 if requested_w <= actual_w {
1152 // Output is already longer than `width`, so don't pad.
1153 emit_without_padding(f)
1155 // We need to add padding. Use the `Formatter::padding` helper function.
1156 let default_align = crate::fmt::rt::v1::Alignment::Left;
1157 let post_padding = f.padding(requested_w - actual_w, default_align)?;
1158 emit_without_padding(f)?;
1159 post_padding.write(f)
1165 // Print leading '+' sign if requested
1166 let prefix = if f.sign_plus() { "+" } else { "" };
1169 fmt_decimal(f, self.secs, self.nanos, NANOS_PER_SEC / 10, prefix, "s")
1170 } else if self.nanos >= NANOS_PER_MILLI {
1173 (self.nanos / NANOS_PER_MILLI) as u64,
1174 self.nanos % NANOS_PER_MILLI,
1175 NANOS_PER_MILLI / 10,
1179 } else if self.nanos >= NANOS_PER_MICRO {
1182 (self.nanos / NANOS_PER_MICRO) as u64,
1183 self.nanos % NANOS_PER_MICRO,
1184 NANOS_PER_MICRO / 10,
1189 fmt_decimal(f, self.nanos as u64, 0, 1, prefix, "ns")
1194 /// An error which can be returned when converting a floating-point value of seconds
1195 /// into a [`Duration`].
1197 /// This error is used as the error type for [`Duration::try_from_secs_f32`] and
1198 /// [`Duration::try_from_secs_f64`].
1203 /// #![feature(duration_checked_float)]
1204 /// use std::time::Duration;
1206 /// if let Err(e) = Duration::try_from_secs_f32(-1.0) {
1207 /// println!("Failed conversion to Duration: {e}");
1210 #[derive(Debug, Clone, PartialEq, Eq)]
1211 #[unstable(feature = "duration_checked_float", issue = "83400")]
1212 pub struct FromFloatSecsError {
1213 kind: FromFloatSecsErrorKind,
1216 impl FromFloatSecsError {
1217 const fn description(&self) -> &'static str {
1219 FromFloatSecsErrorKind::Negative => {
1220 "can not convert float seconds to Duration: value is negative"
1222 FromFloatSecsErrorKind::OverflowOrNan => {
1223 "can not convert float seconds to Duration: value is either too big or NaN"
1229 #[unstable(feature = "duration_checked_float", issue = "83400")]
1230 impl fmt::Display for FromFloatSecsError {
1231 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1232 self.description().fmt(f)
1236 #[derive(Debug, Clone, PartialEq, Eq)]
1237 enum FromFloatSecsErrorKind {
1238 // Value is negative.
1240 // Value is either too big to be represented as `Duration` or `NaN`.
1244 macro_rules! try_from_secs {
1247 mantissa_bits = $mant_bits: literal,
1248 exponent_bits = $exp_bits: literal,
1249 offset = $offset: literal,
1250 bits_ty = $bits_ty:ty,
1251 double_ty = $double_ty:ty,
1253 const MIN_EXP: i16 = 1 - (1i16 << $exp_bits) / 2;
1254 const MANT_MASK: $bits_ty = (1 << $mant_bits) - 1;
1255 const EXP_MASK: $bits_ty = (1 << $exp_bits) - 1;
1257 if $secs.is_sign_negative() {
1258 return Err(FromFloatSecsError { kind: FromFloatSecsErrorKind::Negative });
1261 let bits = $secs.to_bits();
1262 let mant = (bits & MANT_MASK) | (MANT_MASK + 1);
1263 let exp = ((bits >> $mant_bits) & EXP_MASK) as i16 + MIN_EXP;
1265 let (secs, nanos) = if exp < -31 {
1266 // the input represents less than 1ns and can not be rounded to it
1269 // the input is less than 1 second
1270 let t = <$double_ty>::from(mant) << ($offset + exp);
1271 let nanos_offset = $mant_bits + $offset;
1272 let nanos_tmp = u128::from(NANOS_PER_SEC) * u128::from(t);
1273 let nanos = (nanos_tmp >> nanos_offset) as u32;
1275 let rem_mask = (1 << nanos_offset) - 1;
1276 let rem_msb_mask = 1 << (nanos_offset - 1);
1277 let rem = nanos_tmp & rem_mask;
1278 let is_tie = rem == rem_msb_mask;
1279 let is_even = (nanos & 1) == 0;
1280 let rem_msb = nanos_tmp & rem_msb_mask == 0;
1281 let add_ns = !(rem_msb || (is_even && is_tie));
1283 // f32 does not have enough precision to trigger the second branch
1284 // since it can not represent numbers between 0.999_999_940_395 and 1.0.
1285 let nanos = nanos + add_ns as u32;
1286 if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) { (0, nanos) } else { (1, 0) }
1287 } else if exp < $mant_bits {
1288 let secs = u64::from(mant >> ($mant_bits - exp));
1289 let t = <$double_ty>::from((mant << exp) & MANT_MASK);
1290 let nanos_offset = $mant_bits;
1291 let nanos_tmp = <$double_ty>::from(NANOS_PER_SEC) * t;
1292 let nanos = (nanos_tmp >> nanos_offset) as u32;
1294 let rem_mask = (1 << nanos_offset) - 1;
1295 let rem_msb_mask = 1 << (nanos_offset - 1);
1296 let rem = nanos_tmp & rem_mask;
1297 let is_tie = rem == rem_msb_mask;
1298 let is_even = (nanos & 1) == 0;
1299 let rem_msb = nanos_tmp & rem_msb_mask == 0;
1300 let add_ns = !(rem_msb || (is_even && is_tie));
1302 // f32 does not have enough precision to trigger the second branch.
1303 // For example, it can not represent numbers between 1.999_999_880...
1304 // and 2.0. Bigger values result in even smaller precision of the
1306 let nanos = nanos + add_ns as u32;
1307 if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) {
1312 } else if exp < 64 {
1313 // the input has no fractional part
1314 let secs = u64::from(mant) << (exp - $mant_bits);
1317 return Err(FromFloatSecsError { kind: FromFloatSecsErrorKind::OverflowOrNan });
1320 Ok(Duration { secs, nanos })
1325 /// The checked version of [`from_secs_f32`].
1327 /// [`from_secs_f32`]: Duration::from_secs_f32
1329 /// This constructor will return an `Err` if `secs` is negative, overflows `Duration` or not finite.
1333 /// #![feature(duration_checked_float)]
1335 /// use std::time::Duration;
1337 /// let res = Duration::try_from_secs_f32(0.0);
1338 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1339 /// let res = Duration::try_from_secs_f32(1e-20);
1340 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1341 /// let res = Duration::try_from_secs_f32(4.2e-7);
1342 /// assert_eq!(res, Ok(Duration::new(0, 420)));
1343 /// let res = Duration::try_from_secs_f32(2.7);
1344 /// assert_eq!(res, Ok(Duration::new(2, 700_000_048)));
1345 /// let res = Duration::try_from_secs_f32(3e10);
1346 /// assert_eq!(res, Ok(Duration::new(30_000_001_024, 0)));
1347 /// // subnormal float:
1348 /// let res = Duration::try_from_secs_f32(f32::from_bits(1));
1349 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1351 /// let res = Duration::try_from_secs_f32(-5.0);
1352 /// assert!(res.is_err());
1353 /// let res = Duration::try_from_secs_f32(f32::NAN);
1354 /// assert!(res.is_err());
1355 /// let res = Duration::try_from_secs_f32(2e19);
1356 /// assert!(res.is_err());
1358 /// // the conversion uses rounding with tie resolution to even
1359 /// let res = Duration::try_from_secs_f32(0.999e-9);
1360 /// assert_eq!(res, Ok(Duration::new(0, 1)));
1362 /// // this float represents exactly 976562.5e-9
1363 /// let val = f32::from_bits(0x3A80_0000);
1364 /// let res = Duration::try_from_secs_f32(val);
1365 /// assert_eq!(res, Ok(Duration::new(0, 976_562)));
1367 /// // this float represents exactly 2929687.5e-9
1368 /// let val = f32::from_bits(0x3B40_0000);
1369 /// let res = Duration::try_from_secs_f32(val);
1370 /// assert_eq!(res, Ok(Duration::new(0, 2_929_688)));
1372 /// // this float represents exactly 1.000_976_562_5
1373 /// let val = f32::from_bits(0x3F802000);
1374 /// let res = Duration::try_from_secs_f32(val);
1375 /// assert_eq!(res, Ok(Duration::new(1, 976_562)));
1377 /// // this float represents exactly 1.002_929_687_5
1378 /// let val = f32::from_bits(0x3F806000);
1379 /// let res = Duration::try_from_secs_f32(val);
1380 /// assert_eq!(res, Ok(Duration::new(1, 2_929_688)));
1382 #[unstable(feature = "duration_checked_float", issue = "83400")]
1384 pub const fn try_from_secs_f32(secs: f32) -> Result<Duration, FromFloatSecsError> {
1395 /// The checked version of [`from_secs_f64`].
1397 /// [`from_secs_f64`]: Duration::from_secs_f64
1399 /// This constructor will return an `Err` if `secs` is negative, overflows `Duration` or not finite.
1403 /// #![feature(duration_checked_float)]
1405 /// use std::time::Duration;
1407 /// let res = Duration::try_from_secs_f64(0.0);
1408 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1409 /// let res = Duration::try_from_secs_f64(1e-20);
1410 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1411 /// let res = Duration::try_from_secs_f64(4.2e-7);
1412 /// assert_eq!(res, Ok(Duration::new(0, 420)));
1413 /// let res = Duration::try_from_secs_f64(2.7);
1414 /// assert_eq!(res, Ok(Duration::new(2, 700_000_000)));
1415 /// let res = Duration::try_from_secs_f64(3e10);
1416 /// assert_eq!(res, Ok(Duration::new(30_000_000_000, 0)));
1417 /// // subnormal float
1418 /// let res = Duration::try_from_secs_f64(f64::from_bits(1));
1419 /// assert_eq!(res, Ok(Duration::new(0, 0)));
1421 /// let res = Duration::try_from_secs_f64(-5.0);
1422 /// assert!(res.is_err());
1423 /// let res = Duration::try_from_secs_f64(f64::NAN);
1424 /// assert!(res.is_err());
1425 /// let res = Duration::try_from_secs_f64(2e19);
1426 /// assert!(res.is_err());
1428 /// // the conversion uses rounding with tie resolution to even
1429 /// let res = Duration::try_from_secs_f64(0.999e-9);
1430 /// assert_eq!(res, Ok(Duration::new(0, 1)));
1431 /// let res = Duration::try_from_secs_f64(0.999_999_999_499);
1432 /// assert_eq!(res, Ok(Duration::new(0, 999_999_999)));
1433 /// let res = Duration::try_from_secs_f64(0.999_999_999_501);
1434 /// assert_eq!(res, Ok(Duration::new(1, 0)));
1435 /// let res = Duration::try_from_secs_f64(42.999_999_999_499);
1436 /// assert_eq!(res, Ok(Duration::new(42, 999_999_999)));
1437 /// let res = Duration::try_from_secs_f64(42.999_999_999_501);
1438 /// assert_eq!(res, Ok(Duration::new(43, 0)));
1440 /// // this float represents exactly 976562.5e-9
1441 /// let val = f64::from_bits(0x3F50_0000_0000_0000);
1442 /// let res = Duration::try_from_secs_f64(val);
1443 /// assert_eq!(res, Ok(Duration::new(0, 976_562)));
1445 /// // this float represents exactly 2929687.5e-9
1446 /// let val = f64::from_bits(0x3F68_0000_0000_0000);
1447 /// let res = Duration::try_from_secs_f64(val);
1448 /// assert_eq!(res, Ok(Duration::new(0, 2_929_688)));
1450 /// // this float represents exactly 1.000_976_562_5
1451 /// let val = f64::from_bits(0x3FF0_0400_0000_0000);
1452 /// let res = Duration::try_from_secs_f64(val);
1453 /// assert_eq!(res, Ok(Duration::new(1, 976_562)));
1455 /// // this float represents exactly 1.002_929_687_5
1456 /// let val = f64::from_bits(0x3_FF00_C000_0000_000);
1457 /// let res = Duration::try_from_secs_f64(val);
1458 /// assert_eq!(res, Ok(Duration::new(1, 2_929_688)));
1460 #[unstable(feature = "duration_checked_float", issue = "83400")]
1462 pub const fn try_from_secs_f64(secs: f64) -> Result<Duration, FromFloatSecsError> {