std::chrono::duration<Rep,Period>::zero

 

C++

编译器支持

独立和宿主

语言

标准库

标准库头文件

命名要求

Feature test macros (C++20)

语言支持库

Concepts library (C++20)

诊断库

内存管理库

Metaprogramming library (C++11)

通用工具库

容器库

迭代器库

Ranges library (C++20)

算法库

字符串库

文本处理库

数值库

日期和时间库

输入/输出库

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

技术规范

符号索引

外部库

 

日期和时间库

时间点 time_point (C++11) clock_time_conversion (C++20)   clock_cast (C++20) 持续时间 duration (C++11) 时钟 system_clock (C++11) steady_clock (C++11) is_clock (C++20) utc_clock (C++20) tai_clock (C++20) high_resolution_clock (C++11) gps_clock (C++20) file_clock (C++20) local_t (C++20) 一天中的时间 is_amis_pm (C++20)(C++20) make12make24 (C++20)(C++20) hh_mm_ss (C++20)

日历 day (C++20) month (C++20) year (C++20) weekday (C++20) operator/ (C++20) year_month_day (C++20) year_month_day_last (C++20) year_month_weekday (C++20) year_month_weekday_last (C++20)   weekday_indexed (C++20) weekday_last (C++20) month_day (C++20) month_day_last (C++20) month_weekday (C++20) month_weekday_last (C++20) year_month (C++20) last_speclast (C++20)(C++20) chrono I/O parse (C++20)

时区 tzdb (C++20) tzdb_list (C++20) get_tzdbget_tzdb_listreload_tzdbremote_version (C++20)(C++20)(C++20)(C++20) sys_info (C++20) local_info (C++20) nonexistent_local_time (C++20) ambiguous_local_time (C++20) locate_zone (C++20) current_zone (C++20) time_zone (C++20) choose (C++20) zoned_traits (C++20) zoned_time (C++20) time_zone_link (C++20) leap_second (C++20) leap_second_info (C++20) get_leap_second_info (C++20) C 风格日期和时间

 

std::chrono::duration

成员函数
duration::duration duration::operator= duration::count duration::zero duration::min duration::max duration::operator+duration::operator-	duration::operator++duration::operator-- duration::operator+=duration::operator-=duration::operator*=duration::operator/=duration::operator%=
非成员函数
operator+operator-operator*operator/operator% operator==operator!=operator<operator<=operator>operator>=operator<=> (until C++20)(C++20) operator<< (C++20)	duration_cast floor (C++17) ceil (C++17) round (C++17) abs (C++17) operator""h (C++14) operator""min (C++14) operator""s (C++14) operator""ms (C++14) operator""us (C++14) operator""ns (C++14) from_stream (C++20)
辅助类
common_type treat_as_floating_point      duration_values	formatter<std::chrono::duration> (C++20) hash<std::chrono::duration> (C++26)

 

static constexpr duration zero();		(until C++20)
static constexpr duration zero() noexcept;		(since C++20)

返回零长度的持续时间。

如果 duration 的表示 rep 需要其他实现来返回零长度的 duration，则可以特化 std::chrono::duration_values 以返回所需的值。

参数

(无)

返回值

返回 duration(std::chrono::duration_values<rep>::zero())。

示例

运行此代码

#include <chrono>
#include <ratio>
 
template<typename X, typename Y>
using dura = std::chrono::duration<X, Y>;
 
static_assert
(
    (std::chrono::hours::zero() == std::chrono::nanoseconds::zero()) &&
    (dura<short, std::nano>::zero() == dura<int, std::deci>::zero()) &&
    (dura<short, std::deca>::zero() == dura<long, std::exa>::zero()) &&
    (dura<long, std::atto>::zero().count() == dura<float, std::exa>::zero().count())
);
 
int main() {}

参见

min [静态]	返回特殊的 duration 值 min (public static member function)
max [静态]	返回特殊的 duration 值 max (public static member function)