std::chrono::year_month_weekday_last::operator+=, std::chrono::year_month_weekday_last::operator-=

constexpr std::chrono::year_month_weekday_last& operator+=(const std::chrono::years& dy) const noexcept;
(1) (C++20 起)
constexpr std::chrono::year_month_weekday_last& operator+=(const std::chrono::months& dm) const noexcept;
(2) (C++20 起)
constexpr std::chrono::year_month_weekday_last& operator-=(const std::chrono::years& dy) const noexcept;
(3) (C++20 起)
constexpr std::chrono::year_month_weekday_last& operator-=(const std::chrono::months& dm) const noexcept;
(4) (C++20 起)

以时长 dydm 为程度修改时间点 *this

1) 等价于 *this = *this + dy;
2) 等价于 *this = *this + dm;
3) 等价于 *this = *this - dy;
4) 等价于 *this = *this - dm;

对于能转换到 std::chrono::yearsstd::chrono::months 两者的时长,若调用有歧义,则偏好 years 重载 (1,3)

参阅

year_month_weekday_last 与一定数量的 yearsmonths 相加或相减
(函数)