From cppreference.com
template<classRep,classPeriod=std::ratio<1>>classduration;(since C++11)Class template std::chrono::duration represents a time interval.
It consists of a count of ticks of type Rep and a tick period, where the tick period is a compile-time rational
representing the time in seconds from one tick to the next.
The only data stored in a duration is a tick count of type Rep. If Rep is floating point, then the duration can represent fractions of ticks. Period is included as part of the duration's type, and is only used when converting between different durations.
Member types
Member type Definition repRep, an arithmetic type, or a class emulating an arithmetic type, representing the number of ticks periodPeriod(until C++17)typenamePeriod::type(since C++17), a
representing the tick period (i.e. the number of second's fractions per tick) Member functions
constructs new duration
(public member function)
assigns the contents
(public member function)
returns the count of ticks
(public member function)
[static]
returns the special duration value zero
(public static member function)
[static]
returns the special duration value min
(public static member function)
[static]
returns the special duration value max
(public static member function)
implements unary + and unary -
(public member function)
operator++operator++(int)operator--operator--(int)
increments or decrements the tick count
(public member function)
operator+=operator-=operator*=operator/=operator%=
implements compound assignment between two durations
(public member function)
Non-member functions
operator+operator-operator*operator/operator%
(C++11)
implements arithmetic operations with durations as arguments
(function template)
operator==operator!=operator<operator<=operator>operator>=operator<=>
(C++11)(C++11)(removed in C++20)(C++11)(C++11)(C++11)(C++11)(C++20)
compares two durations
(function template)
(C++11)
converts a duration to another, with a different tick interval
(function template)
(C++17)
converts a duration to another, rounding down
(function template)
(C++17)
converts a duration to another, rounding up
(function template)
(C++17)
converts a duration to another, rounding to nearest, ties to even
(function template)
(C++17)
obtains the absolute value of the duration
(function template)
(C++20)
performs stream output on a duration
(function template)
(C++20)
parses a duration from a stream according to the provided format
(function template)
Helper types
A type /* intXX */ used in the table below means a signed integer type of at least XX bits.
Type Definition std::chrono::nanosecondsstd::chrono::duration</* int64 */,std::nano>std::chrono::microsecondsstd::chrono::duration</* int55 */,std::micro>std::chrono::millisecondsstd::chrono::duration</* int45 */,std::milli>std::chrono::secondsstd::chrono::duration</* int35 */>std::chrono::minutesstd::chrono::duration</* int29 */,std::ratio<60>>std::chrono::hoursstd::chrono::duration</* int23 */,std::ratio<3600>>std::chrono::days(since C++20)std::chrono::duration</* int25 */,std::ratio<86400>>std::chrono::weeks(since C++20)std::chrono::duration</* int22 */,std::ratio<604800>>std::chrono::months(since C++20)std::chrono::duration</* int20 */,std::ratio<2629746>>std::chrono::years(since C++20)std::chrono::duration</* int17 */,std::ratio<31556952>>Note: each of the predefined duration types up to hours covers a range of at least ±292 years.
Each of the predefined duration types days, weeks, months and years covers a range of at least ±40000 years. years is equal to 365.2425 days (the average length of a Gregorian year). months is equal to 30.436875 days (exactly 1/12 of years).
(since C++20)Helper classes
Helper specializations
template<classRep,classPeriod>constexprboolenable_nonlocking_formatter_optimization<chrono::duration<Rep,Period>>=enable_nonlocking_formatter_optimization<Rep>;(since C++23)This specialization of
std::enable_nonlocking_formatter_optimization
enables efficient implementation of
and
for printing a chrono::duration object when the template parameter Rep enables it.
Literals
Defined in inline namespace std::literals::chrono_literals
(C++14)
a
literal representing hours
(function)
(C++14)
a
literal representing minutes
(function)
(C++14)
a
literal representing seconds
(function)
(C++14)
a
literal representing milliseconds
(function)
(C++14)
a
literal representing microseconds
(function)
(C++14)
a
literal representing nanoseconds
(function)
Note: the literal suffixes d and y do not refer to days and years but to
and
, respectively.
(since C++20)Notes
The actual time interval (in seconds) that is held by a duration object d is roughly equal to d.count()*D::period::num/D::period::den, where D is of type chrono::duration<> and d is an object of such type.
macroValueStdFeature
(C++14)
User-defined literals for time types
Example
This example shows how to define several custom duration types and convert between types:
Run this code
#include<chrono>#include<iostream>usingnamespacestd::chrono_literals;template<typenameT1,typenameT2>usingmul=std::ratio_multiply<T1,T2>;intmain(){usingmicrofortnights=std::chrono::duration<float,mul<mul<std::ratio<2>,std::chrono::weeks::period>,std::micro>>;usingnanocenturies=std::chrono::duration<float,mul<mul<std::hecto,std::chrono::years::period>,std::nano>>;usingfps_24=std::chrono::duration<double,std::ratio<1,24>>;std::cout<<"1 second is:\n";// integer scale conversion with no precision loss: no caststd::cout<<std::chrono::milliseconds(1s).count()<<" milliseconds\n"<<std::chrono::microseconds(1s).count()<<" microseconds\n"<<std::chrono::nanoseconds(1s).count()<<" nanoseconds\n";// integer scale conversion with precision loss: requires a caststd::cout<<std::chrono::duration_cast<std::chrono::minutes>(1s).count()<<" minutes\n";// alternative to duration_cast:std::cout<<1s/1min<<" minutes\n";// floating-point scale conversion: no caststd::cout<<microfortnights(1s).count()<<" microfortnights\n"<<nanocenturies(1s).count()<<" nanocenturies\n"<<fps_24(1s).count()<<" frames at 24fps\n";}Output:
1 second is: 1000 milliseconds 1000000 microseconds 1000000000 nanoseconds 0 minutes 0 minutes 0.82672 microfortnights 0.316887 nanocenturies 24 frames at 24fps