25 Time library [time]

25.8 The civil calendar [time.cal]

25.8.11 Class month_­weekday [time.cal.mwd]

25.8.11.1 Overview [time.cal.mwd.overview]

namespace std::chrono {
  class month_weekday {
    chrono::month           m_;         // exposition only
    chrono::weekday_indexed wdi_;       // exposition only
  public:
    constexpr month_weekday(const chrono::month& m, const chrono::weekday_indexed& wdi) noexcept;

    constexpr chrono::month           month()           const noexcept;
    constexpr chrono::weekday_indexed weekday_indexed() const noexcept;
    constexpr bool ok() const noexcept;
  };
}
month_­weekday represents the weekday of a month, of an as yet unspecified year.
To do this the month_­weekday stores a month and a weekday_­indexed.
[Example
:
constexpr auto mwd
    = February/Tuesday[3];               // mwd is the third Tuesday of February of an as yet unspecified year
static_assert(mwd.month() == February);
static_assert(mwd.weekday_indexed() == Tuesday[3]);
end example
]
month_­weekday is a trivially copyable and standard-layout class type.