cppdraft_translate/cppdraft/time/hms/members.md

[time.hms.members]

30 Time library [time]

30.9 Class template hh_mm_ss [time.hms]

30.9.2 Members [time.hms.members]

🔗

static constexpr unsigned fractional_width = see below;

1

#

fractional_width is the number of fractional decimal digits represented by precision.

fractional_width has the value of the smallest possible integer in the range [0, 18] such thatprecision will exactly represent all values of Duration.

If no such value of fractional_width exists, thenfractional_width is 6.

[Example 1:

See Table 132 for some durations, the resulting fractional_width, and the formatted fractional second output of Duration{1}.

Table 132 — Examples for fractional_width [tab:time.hms.width]

🔗 Duration	fractional_width	Formatted fractional second output
🔗 hours, minutes, and seconds	0
🔗 milliseconds	3	0.001
🔗 microseconds	6	0.000001
🔗 nanoseconds	9	0.000000001
🔗 duration<int, ratio<1, 2>>	1	0.5
🔗 duration<int, ratio<1, 3>>	6	0.333333
🔗 duration<int, ratio<1, 4>>	2	0.25
🔗 duration<int, ratio<1, 5>>	1	0.2
🔗 duration<int, ratio<1, 6>>	6	0.166666
🔗 duration<int, ratio<1, 7>>	6	0.142857
🔗 duration<int, ratio<1, 8>>	3	0.125
🔗 duration<int, ratio<1, 9>>	6	0.111111
🔗 duration<int, ratio<1, 10>>	1	0.1
🔗 duration<int, ratio<756, 625>>	4	0.2096

— end example]

🔗

using precision = see below;

2

#

precision isduration<common_type_t<Duration::rep, seconds::rep>, ratio<1, 10fractional_width>>

🔗

constexpr explicit hh_mm_ss(Duration d);

3

#

Effects: Constructs an object of type hh_mm_ss which represents the Duration d with precision precision.

• (3.1)

  Initializes is_neg with d < Duration​::​zero().

• (3.2)

  Initializes h with duration_cast<chrono​::​hours>(abs(d)).

• (3.3)

  Initializes m with duration_cast<chrono​::​minutes>(abs(d) - hours()).

• (3.4)

  Initializes s with duration_cast<chrono​::​seconds>(abs(d) - hours() - minutes()).

• (3.5)

  If treat_as_floating_point_v<precision​::​rep> is true, initializes ss with abs(d) - hours() - minutes() - seconds(). Otherwise, initializes ss with duration_cast(abs(d) - hours() - minutes() - seconds()).

[Note 1:

When precision​::​rep is integral andprecision​::​period is ratio<1>,subseconds() always returns a value equal to 0s.

— end note]

4

#

Postconditions: If treat_as_floating_point_v<precision​::​rep> is true,to_duration() returns d, otherwise to_duration() returns duration_cast(d).

🔗

constexpr bool is_negative() const noexcept;

5

#

Returns: is_neg.

🔗

constexpr chrono::hours hours() const noexcept;

6

#

Returns: h.

🔗

constexpr chrono::minutes minutes() const noexcept;

7

#

Returns: m.

🔗

constexpr chrono::seconds seconds() const noexcept;

8

#

Returns: s.

🔗

constexpr precision subseconds() const noexcept;

9

#

Returns: ss.

🔗

constexpr precision to_duration() const noexcept;

10

#

Returns: If is_neg, returns -(h + m + s + ss), otherwise returns h + m + s + ss.

🔗

constexpr explicit operator precision() const noexcept;

11

#

Returns: to_duration().