std::chrono::duration<Rep,Period>::operator=

 

C++

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Freestanding and hosted

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Standard library

Standard library headers

Named requirements

Feature test macros(C++20)

Language support library

Concepts library(C++20)

Diagnostics library

Memory management library

Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

Execution control library(C++26)

Technical specifications

Symbols index

External libraries

 

Date and time library

Time point time_point (C++11) clock_time_conversion (C++20)   clock_cast (C++20) Duration duration (C++11) Clocks 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) Time of day is_amis_pm (C++20)(C++20) make12make24 (C++20)(C++20) hh_mm_ss (C++20)

Calendar 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)

Time zone 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-style date and time

 

std::chrono::duration

Member functions
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%=
Non-member functions
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)
Helper classes
common_type treat_as_floating_point      duration_values	formatter<std::chrono::duration> (C++20) hash<std::chrono::duration> (C++26)

 

duration& operator=(const duration &other )=default;		(since C++11)

Assigns the contents of one duration to another.

Parameters

other

-

duration to copy from

Example

Run this code

#include <chrono>#include <iostream>   int main(){usingnamespace std::chrono_literals;   std::chrono::hours z_hours{};std::chrono::seconds z_seconds{};   z_hours = 2h;// ok, no conversion needed   z_seconds = z_hours;// First, the converting ctor is used to create a temporary object of `lhs`s type.// This ctor implicitly invokes the casting function// chrono::duration_cast<std::seconds>(z_hours). The resulting `rhs` rvalue// has the same type as `lhs`, and the `operator=` finally performs the assignment.   std::cout<<"hours: "<< z_hours.count()<<'\n';std::cout<<"seconds: "<< z_seconds.count()<<'\n';   z_seconds -= 42s;   // z_hours = z_seconds; // compile-time error (which is good): incompatible types.// The library avoids the implicit cast to prevent a potential precision loss.   z_hours =std::chrono::duration_cast<std::chrono::hours>(z_seconds);// ok z_hours =std::chrono::duration_cast<decltype(z_hours)>(z_seconds);// ditto   std::cout<<"hours: "<< z_hours.count()<<'\n';std::cout<<"seconds: "<< z_seconds.count()<<'\n';   std::chrono::duration<double, std::ratio<3600>> z2_hours{};   z2_hours = z_seconds;// ok, no truncation, implicit cast   std::cout<<"hours: "<< z2_hours.count()<<'\n';}

Output:

hours: 2 seconds: 7200 hours: 1 seconds: 7158 hours: 1.98833

See also

(constructor)

constructs new duration (public member function)