29 Time library [time]

29.9 Class template hh_mm_ss [time.hms]

29.9.1 Overview [time.hms.overview]

namespace std::chrono { template<class Duration> class hh_mm_ss { public: static constexpr unsigned fractional_width = see below; using precision = see below; constexpr hh_mm_ss() noexcept : hh_mm_ss{Duration::zero()} {} constexpr explicit hh_mm_ss(Duration d); constexpr bool is_negative() const noexcept; constexpr chrono::hours hours() const noexcept; constexpr chrono::minutes minutes() const noexcept; constexpr chrono::seconds seconds() const noexcept; constexpr precision subseconds() const noexcept; constexpr explicit operator precision() const noexcept; constexpr precision to_duration() const noexcept; private: bool is_neg; // exposition only chrono::hours h; // exposition only chrono::minutes m; // exposition only chrono::seconds s; // exposition only precision ss; // exposition only }; }
The hh_mm_ss class template splits a duration into a multi-field time structure hours:minutes:seconds and possibly subseconds, where subseconds will be a duration unit based on a non-positive power of 10.
The Duration template parameter dictates the precision to which the time is split.
A hh_mm_ss models negative durations with a distinct is_negative getter that returns true when the input duration is negative.
The individual duration fields always return non-negative durations even when is_negative() indicates the structure is representing a negative duration.
If Duration is not a specialization of duration, the program is ill-formed.