[time.clock.cast.fn] (original) (raw)

30 Time library [time]

30.7 Clocks [time.clock]

30.7.10 time_point conversions [time.clock.cast]

30.7.10.6 Function template clock_cast [time.clock.cast.fn]

template<class DestClock, class SourceClock, class Duration> auto clock_cast(const time_point<SourceClock, Duration>& t);

Constraints: At least one of the following clock time conversion expressions is well-formed:

• clock_time_conversion<DestClock, SourceClock>{}(t)
• clock_time_conversion<DestClock, system_clock>{}( clock_time_conversion<system_clock, SourceClock>{}(t))
• clock_time_conversion<DestClock, utc_clock>{}( clock_time_conversion<utc_clock, SourceClock>{}(t))
• clock_time_conversion<DestClock, utc_clock>{}( clock_time_conversion<utc_clock, system_clock>{}( clock_time_conversion<system_clock, SourceClock>{}(t)))
• clock_time_conversion<DestClock, system_clock>{}( clock_time_conversion<system_clock, utc_clock>{}( clock_time_conversion<utc_clock, SourceClock>{}(t)))

A clock time conversion expression is considered better than another clock time conversion expression if it involves feweroperator() calls on clock_time_conversionspecializations.

Mandates: Among the well-formed clock time conversion expressions from the above list, there is a unique best expression.

Returns: The best well-formed clock time conversion expression in the above list.