std::chrono::choose

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Defined in header <chrono>
enum class choose { earliest, latest };		(since C++20)

The scoped enumeration choose can be passed to certain member functions of std::chrono::time_zone and std::chrono::zoned_time to control how ambiguous or nonexistent local times should be resolved. Passing choose::earliest causes the earlier time point to be returned, while passing choose::latest causes the later time point to be returned. (For nonexistent local times, these two time points are identical.)

If a choose is not passed and an ambiguous or nonexistent local time is encountered, a std::chrono::ambiguous_local_time or std::chrono::nonexistent_local_time exception (as applicable) will be thrown.