标准库头文件 <chrono>
此头文件是日期和时间库的一部分。
类
定义于命名空间
std::chrono | |
(C++11) |
时间区间 (类模板) |
(C++11) |
来自系统范畴实时时钟的挂钟时间 (类) |
(C++11) |
决不会调整的单调时钟 (类) |
(C++11) |
拥有可用的最短嘀嗒周期的时钟 (类) |
(C++11) |
时间中的点 (类模板) |
指示时长可转换为拥有不同嘀嗒周期的时长 (类模板) | |
构造给定类型的嘀嗒计数的零、最小及最大值 (类模板) | |
(C++20) |
表示时区 (类) |
(C++20) |
抛出以报告本地时间不存在的异常 (类) |
(C++20) |
抛出以报告本地时间有歧义的异常 (类) |
便利 typedef | |
定义于命名空间
std::chrono | |
std::chrono::nanoseconds | Period 为 std::nano 的时长类型 |
std::chrono::microseconds | Period 为 std::micro 的时长类型 |
std::chrono::milliseconds | Period 为 std::milli 的时长类型 |
std::chrono::seconds | Period 为 std::ratio<1> 的时长类型 |
std::chrono::minutes | Period 为 std::ratio<60> 的时长类型 |
std::chrono::hours | Period 为 std::ratio<3600> 的时长类型 |
std::chrono::days | Period 为 std::ratio<86400> 的时长类型 |
std::chrono::weeks | Period 为 std::ratio<604800> 的时长类型 |
std::chrono::months | Period 为 std::ratio<2629746> 的时长类型 |
std::chrono::years | Period 为 std::ratio<31556952> 的时长类型 |
特化 | |
定义于命名空间
std | |
特化 std::common_type 特征 (类模板特化) | |
特化 std::common_type 特征 (类模板特化) |
函数
duration | |
定义于命名空间
std::chrono | |
实现以时长为实参的算术运算 (函数模板) | |
(C++20 中移除)(C++20) |
比较两个时长 (函数模板) |
转换时长到另一个拥有不同嘀嗒间隔的时长 (函数模板) | |
(C++17) |
以向下取整的方式,将一个时长转换为另一个时长 (函数模板) |
(C++17) |
以向上取整的方式,将一个时长转换为另一个时长 (函数模板) |
(C++17) |
转换时长到另一个时长,就近取整,偶数优先 (函数模板) |
(C++17) |
获取时长的绝对值 (函数模板) |
time_point | |
定义于命名空间
std::chrono | |
实施涉及时间点的加法和减法运算 (函数模板) | |
(C++20 中移除)(C++20) |
比较两个时间点 (函数模板) |
转换时间点为同一时钟上拥有不同时长的另一时间点 (函数模板) | |
转换 time_point 到另一个,向下取整 (函数模板) | |
转换 time_point 到另一个,向上取整 (函数模板) | |
转换 time_point 到另一个,就近取整,偶数优先 (函数模板) | |
字面量 | |
定义于内联命名空间
std::literals::chrono_literals | |
(C++14) |
表示小时的 std::chrono::duration 字面量 (函数) |
(C++14) |
表示分钟的 std::chrono::duration 字面量 (函数) |
(C++14) |
表示秒的 std::chrono::duration 字面量 (函数) |
(C++14) |
表示毫秒的 std::chrono::duration 字面量 (函数) |
(C++14) |
表示微秒的 std::chrono::duration 字面量 (函数) |
(C++14) |
表示纳秒的 std::chrono::duration 字面量 (函数) |
(C++20) |
表示月内日期的 std::chrono::day 字面量 (函数) |
(C++20) |
表示特定年的 std::chrono::year 字面量 (函数) |
概要
namespace std { namespace chrono { // 类模板 duration template <class Rep, class Period = ratio<1>> class duration; // 类模板 time_point template <class Clock, class Duration = typename Clock::duration> class time_point; } // common_type 特化 template <class Rep1, class Period1, class Rep2, class Period2> struct common_type<chrono::duration<Rep1, Period1>, chrono::duration<Rep2, Period2>>; template <class Clock, class Duration1, class Duration2> struct common_type<chrono::time_point<Clock, Duration1>, chrono::time_point<Clock, Duration2>>; namespace chrono { // 定制的特征 template <class Rep> struct treat_as_floating_point; template <class Rep> struct duration_values; template <class Rep> constexpr bool treat_as_floating_point_v = treat_as_floating_point<Rep>::value; // duration 算术 template <class Rep1, class Period1, class Rep2, class Period2> common_type_t<duration<Rep1, Period1>, duration<Rep2, Period2>> constexpr operator+(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> common_type_t<duration<Rep1, Period1>, duration<Rep2, Period2>> constexpr operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period, class Rep2> duration<common_type_t<Rep1, Rep2>, Period> constexpr operator*(const duration<Rep1, Period>& d, const Rep2& s); template <class Rep1, class Rep2, class Period> duration<common_type_t<Rep1, Rep2>, Period> constexpr operator*(const Rep1& s, const duration<Rep2, Period>& d); template <class Rep1, class Period, class Rep2> duration<common_type_t<Rep1, Rep2>, Period> constexpr operator/(const duration<Rep1, Period>& d, const Rep2& s); template <class Rep1, class Period1, class Rep2, class Period2> common_type_t<Rep1, Rep2> constexpr operator/(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period, class Rep2> duration<common_type_t<Rep1, Rep2>, Period> constexpr operator%(const duration<Rep1, Period>& d, const Rep2& s); template <class Rep1, class Period1, class Rep2, class Period2> common_type_t<duration<Rep1, Period1>, duration<Rep2, Period2>> constexpr operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); // duration 比较 template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator==(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator!=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator< (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator<=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator> (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Rep2, class Period2> constexpr bool operator>=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs); // duration_cast template <class ToDuration, class Rep, class Period> constexpr ToDuration duration_cast(const duration<Rep, Period>& d); template <class ToDuration, class Rep, class Period> constexpr ToDuration floor(const duration<Rep, Period>& d); template <class ToDuration, class Rep, class Period> constexpr ToDuration ceil(const duration<Rep, Period>& d); template <class ToDuration, class Rep, class Period> constexpr ToDuration round(const duration<Rep, Period>& d); // 便利 typedef using nanoseconds = duration</* 至少 64 位的有符号整数类型 */ , nano>; using microseconds = duration</* 至少 55 位的有符号整数类型 */ , micro>; using milliseconds = duration</* 至少 45 位的有符号整数类型 */ , milli>; using seconds = duration</* 至少 35 位的有符号整数类型 */ >; using minutes = duration</* 至少 29 位的有符号整数类型 */ , ratio< 60>>; using hours = duration</* 至少 23 位的有符号整数类型 */ , ratio<3600>>; // time_point 算术 template <class Clock, class Duration1, class Rep2, class Period2> constexpr time_point<Clock, common_type_t<Duration1, duration<Rep2, Period2>>> operator+(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs); template <class Rep1, class Period1, class Clock, class Duration2> constexpr time_point<Clock, common_type_t<duration<Rep1, Period1>, Duration2>> operator+(const duration<Rep1, Period1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Rep2, class Period2> constexpr time_point<Clock, common_type_t<Duration1, duration<Rep2, Period2>>> operator-(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr common_type_t<Duration1, Duration2> operator-(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); // time_point 比较 template <class Clock, class Duration1, class Duration2> constexpr bool operator==(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr bool operator!=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr bool operator< (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr bool operator<=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr bool operator> (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); template <class Clock, class Duration1, class Duration2> constexpr bool operator>=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs); // time_point_cast template <class ToDuration, class Clock, class Duration> constexpr time_point<Clock, ToDuration> time_point_cast(const time_point<Clock, Duration>& t); template <class ToDuration, class Clock, class Duration> constexpr time_point<Clock, ToDuration> floor(const time_point<Clock, Duration>& tp); template <class ToDuration, class Clock, class Duration> constexpr time_point<Clock, ToDuration> ceil(const time_point<Clock, Duration>& tp); template <class ToDuration, class Clock, class Duration> constexpr time_point<Clock, ToDuration> round(const time_point<Clock, Duration>& tp); // 特化的算法 template <class Rep, class Period> constexpr duration<Rep, Period> abs(duration<Rep, Period> d); // 时钟 class system_clock; class steady_clock; class high_resolution_clock; } inline namespace literals { inline namespace chrono_literals { // duration 字面量后缀 constexpr chrono::hours operator "" h(unsigned long long); constexpr chrono::duration</* 未指明 */, ratio<3600,1>> operator "" h(long double); constexpr chrono::minutes operator "" min(unsigned long long); constexpr chrono::duration</* 未指明 */, ratio<60,1>> operator "" min(long double); constexpr chrono::seconds operator "" s(unsigned long long); constexpr chrono::duration</* 未指明 */ > operator "" s(long double); constexpr chrono::milliseconds operator "" ms(unsigned long long); constexpr chrono::duration</* 未指明 */, milli> operator "" ms(long double); constexpr chrono::microseconds operator "" us(unsigned long long); constexpr chrono::duration</* 未指明 */, micro> operator "" us(long double); constexpr chrono::nanoseconds operator "" ns(unsigned long long); constexpr chrono::duration</* 未指明 */, nano> operator "" ns(long double); constexpr chrono::day operator""d(unsigned long long d) noexcept; constexpr chrono::year operator""y(unsigned long long y) noexcept; } } namespace chrono { using namespace literals::chrono_literals; }
std::chrono::treat_as_floating_point
template <class Rep> struct treat_as_floating_point : is_floating_point<Rep> { };
std::chrono::duration_values
template <class Rep> struct duration_values { public: static constexpr Rep zero(); static constexpr Rep min(); static constexpr Rep max(); };
std::chrono::duration
template <class Rep, class Period = ratio<1>> class duration { public: using rep = Rep; using period = Period; private: rep rep_; // 仅用于阐释 public: // 构造/复制/销毁 constexpr duration() = default; template <class Rep2> constexpr explicit duration(const Rep2& r); template <class Rep2, class Period2> constexpr duration(const duration<Rep2, Period2>& d); ~duration() = default; duration(const duration&) = default; duration& operator=(const duration&) = default; // 探察函数 constexpr rep count() const; // 算术 constexpr duration operator+() const; constexpr duration operator-() const; constexpr duration& operator++(); constexpr duration operator++(int); constexpr duration& operator--(); constexpr duration operator--(int); constexpr duration& operator+=(const duration& d); constexpr duration& operator-=(const duration& d); constexpr duration& operator*=(const rep& rhs); constexpr duration& operator/=(const rep& rhs); constexpr duration& operator%=(const rep& rhs); constexpr duration& operator%=(const duration& rhs); // 特殊值 static constexpr duration zero(); static constexpr duration min(); static constexpr duration max(); };
std::chrono::time_point
template <class Clock, class Duration = typename Clock::duration> class time_point { public: using clock = Clock; using duration = Duration; using rep = typename duration::rep; using period = typename duration::period; private: duration d_; // 仅用于阐释 public: // 构造 constexpr time_point(); // 拥有纪元值 constexpr explicit time_point(const duration& d); // 同 time_point() + d template <class Duration2> constexpr time_point(const time_point<clock, Duration2>& t); // 探察函数 constexpr duration time_since_epoch() const; // 算术 constexpr time_point& operator+=(const duration& d); constexpr time_point& operator-=(const duration& d); // 特殊值 static constexpr time_point min(); static constexpr time_point max(); };
std::chrono::system_clock
class system_clock { public: using rep = /* 见说明 */ ; using period = ratio</* 未指明 */, /* 未指明 */ >; using duration = chrono::duration<rep, period>; using time_point = chrono::time_point<system_clock>; static constexpr bool is_steady = /* 未指明 */ ; static time_point now() noexcept; // 映射到 C API static time_t to_time_t (const time_point& t) noexcept; static time_point from_time_t(time_t t) noexcept; };
std::chrono::steady_clock
class steady_clock { public: using rep = /* 未指明 */ ; using period = ratio</* 未指明 */, /* 未指明 */ >; using duration = chrono::duration<rep, period>; using time_point = chrono::time_point</* 未指明 */, duration>; static constexpr bool is_steady = true; static time_point now() noexcept; };
std::chrono::high_resolution_clock
class high_resolution_clock { public: using rep = /* 未指明 */ ; using period = ratio</* 未指明 */, /* 未指明 */ >; using duration = chrono::duration<rep, period>; using time_point = chrono::time_point</* 未指明 */, duration>; static constexpr bool is_steady = /* 未指明 */ ; static time_point now() noexcept; };