26 Time library [time]

26.8 The civil calendar [time.cal]

26.8.2 Class last_­spec [time.cal.last]

namespace std::chrono {
  struct last_spec {
    explicit last_spec() = default;
  };
}
The type last_­spec is used in conjunction with other calendar types to specify the last in a sequence.
For example, depending on context, it can represent the last day of a month, or the last day of the week of a month.