std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday_last) (3) Linux Manual Page

std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday_last) – std::chrono::operator+,std::chrono::operator-(std::chrono::year_month_weekday_last)

Synopsis

constexpr std::chrono::year_month_weekday_last

operator+(const std::chrono::year_month_weekday_last &ymwdl, (since C++ 20)

                                                                 const std::chrono::months &dm) noexcept;

constexpr std::chrono::year_month_weekday_last

operator+(const std::chrono::months &dm, (since C++ 20)

                                             const std::chrono::year_month_weekday_last &ymwdl) noexcept;

constexpr std::chrono::year_month_weekday_last

operator+(const std::chrono::year_month_weekday_last &ymwdl, (since C++ 20)

                                                                 const std::chrono::years &dy) noexcept;

constexpr std::chrono::year_month_weekday_last

operator+(const std::chrono::years &dy, (since C++ 20)

                                            const std::chrono::year_month_weekday_last &ymwdl) noexcept;

constexpr std::chrono::year_month_weekday_last

operator-(const std::chrono::year_month_weekday_last &ymwdl, (since C++ 20)

                                                                 const std::chrono::months &dm) noexcept;

constexpr std::chrono::year_month_weekday_last

operator-(const std::chrono::year_month_weekday_last &ymwdl, (since C++ 20)

                                                                 const std::chrono::years &dy) noexcept;

1-2) Adds dm.count() months to the date represented by ymwdl. The result has the same year() and month() as std::chrono::year_month(ymwdl.year(), ymwdl.month()) + dm and the same weekday() as ymwdl.
3-4) Adds dy.count() years to the date represented by ymwdl. The result is equivalent to std::chrono::year_month_weekday_last(ymwdl.year() + dy, ymwdl.month(), ymwd.weekday_last()).
5) Subtracts dm.count() months from the date represented by ymwdl. Equivalent to ymwdl+ -dm.
6) Subtracts dy.count() years from the date represented by ymwdl. Equivalent to ymwdl + -dy.