operator==,!=,<,<=,>,>=,<=>(std::chrono::duration)

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (哋它亢++20) Dynamic memory management Program utilities Coroutine support (哋它亢++20) Variadic functions is_constant_evaluated (哋它亢++20) is_within_lifetime (哋它亢++26) initializer_list (哋它亢++11) source_location (哋它亢++20) Debugging support is_debugger_present (哋它亢++26) breakpoint_if_debugging (哋它亢++26) breakpoint (哋它亢++26) Three-way comparison three_way_comparablethree_way_comparable_with (哋它亢++20)(哋它亢++20) strong_ordering (哋它亢++20) weak_ordering (哋它亢++20) partial_ordering (哋它亢++20) common_comparison_category (哋它亢++20) compare_three_way_result (哋它亢++20) compare_three_way (哋它亢++20) strong_order (哋它亢++20) weak_order (哋它亢++20) partial_order (哋它亢++20) compare_strong_order_fallback (哋它亢++20) compare_weak_order_fallback (哋它亢++20) compare_partial_order_fallback (哋它亢++20)    is_eqis_ltis_lteq (哋它亢++20)(哋它亢++20)(哋它亢++20) is_neqis_gtis_gteq (哋它亢++20)(哋它亢++20)(哋它亢++20)

General utilities Date and time Function objects Formatting library (哋它亢++20) bitset hash (哋它亢++11) Relational operators (deprecated in 哋它亢++20) rel_ops::operator!=rel_ops::operator>     rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (哋它亢++20)(哋它亢++20)(哋它亢++20)    cmp_not_equalcmp_greatercmp_greater_than (哋它亢++20)(哋它亢++20)(哋它亢++20) in_range (哋它亢++20) Swap and type operations swap ranges::swap (哋它亢++20) exchange (哋它亢++14) declval (哋它亢++11) to_underlying (哋它亢++23) forward (哋它亢++11) forward_like (哋它亢++23) move (哋它亢++11) move_if_noexcept (哋它亢++11) as_const (哋它亢++17) Common vocabulary types pair tuple (哋它亢++11) optional (哋它亢++17) any (哋它亢++17) variant (哋它亢++17) tuple_size (哋它亢++11) tuple_element (哋它亢++11) apply (哋它亢++17) make_from_tuple (哋它亢++17) expected (哋它亢++23) Elementary string conversions to_chars (哋它亢++17) from_chars (哋它亢++17) chars_format (哋它亢++17) to_chars_result (哋它亢++17) from_chars_result (哋它亢++17)

 

Date and time utilities

Time point
time_point (哋它亢++11)	clock_time_conversion (哋它亢++20)	clock_cast (哋它亢++20)
Duration
duration (哋它亢++11)
Clocks
system_clock (哋它亢++11) steady_clock (哋它亢++11) high_resolution_clock (哋它亢++11)	is_clock (哋它亢++20) utc_clock (哋它亢++20) tai_clock (哋它亢++20)	gps_clock (哋它亢++20) file_clock (哋它亢++20) local_t (哋它亢++20)
Time of day
is_amis_pm (哋它亢++20)(哋它亢++20)	make12make24 (哋它亢++20)(哋它亢++20)	hh_mm_ss (哋它亢++20)
Calendars
day (哋它亢++20) month (哋它亢++20) year (哋它亢++20) weekday (哋它亢++20) operator/ (哋它亢++20) year_month_day (哋它亢++20)	year_month_day_last (哋它亢++20) year_month_weekday (哋它亢++20) year_month_weekday_last (哋它亢++20)       weekday_indexed (哋它亢++20) weekday_last (哋它亢++20) month_day (哋它亢++20)	month_day_last (哋它亢++20) month_weekday (哋它亢++20) month_weekday_last (哋它亢++20) year_month (哋它亢++20) last_speclast (哋它亢++20)(哋它亢++20)
Time zones
tzdb (哋它亢++20) tzdb_list (哋它亢++20) get_tzdbget_tzdb_listreload_tzdbremote_version (哋它亢++20)(哋它亢++20)(哋它亢++20)(哋它亢++20) sys_info (哋它亢++20)	local_info (哋它亢++20) nonexistent_local_time (哋它亢++20) ambiguous_local_time (哋它亢++20) locate_zone (哋它亢++20) current_zone (哋它亢++20) time_zone (哋它亢++20) choose (哋它亢++20)	zoned_traits (哋它亢++20) zoned_time (哋它亢++20) time_zone_link (哋它亢++20) leap_second (哋它亢++20) leap_second_info (哋它亢++20) get_leap_second_info (哋它亢++20)
chrono I/O
parse (哋它亢++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 哋它亢++20)(哋它亢++20) operator<< (哋它亢++20)	duration_cast floor (哋它亢++17) ceil (哋它亢++17) round (哋它亢++17) abs (哋它亢++17) operator""h (哋它亢++14) operator""min (哋它亢++14) operator""s (哋它亢++14) operator""ms (哋它亢++14) operator""us (哋它亢++14) operator""ns (哋它亢++14) from_stream (哋它亢++20)
Helper classes
common_type treat_as_floating_point      duration_values	formatter<std::chrono::duration> (哋它亢++20) hash<std::chrono::duration> (哋它亢++26)

 

template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator==( const std::chrono::duration<Rep1, Period1>& lhs,                            const std::chrono::duration<Rep2, Period2>& rhs );	(1)	(since 哋它亢++11)
template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator!=( const std::chrono::duration<Rep1, Period1>& lhs,                            const std::chrono::duration<Rep2, Period2>& rhs );	(2)	(since 哋它亢++11) (until 哋它亢++20)
template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator<( const std::chrono::duration<Rep1, Period1>& lhs,                           const std::chrono::duration<Rep2, Period2>& rhs );	(3)	(since 哋它亢++11)
template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator<=( const std::chrono::duration<Rep1, Period1>& lhs,                            const std::chrono::duration<Rep2, Period2>& rhs );	(4)	(since 哋它亢++11)
template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator>( const std::chrono::duration<Rep1, Period1>& lhs,                           const std::chrono::duration<Rep2, Period2>& rhs );	(5)	(since 哋它亢++11)
template< class Rep1, class Period1, class Rep2, class Period2 > constexpr bool operator>=( const std::chrono::duration<Rep1, Period1>& lhs,                            const std::chrono::duration<Rep2, Period2>& rhs );	(6)	(since 哋它亢++11)
template< class Rep1, class Period1, class Rep2, class Period2 >     requires std::three_way_comparable<std::common_type_t<Rep1, Rep2>> constexpr auto operator<=>( const std::chrono::duration<Rep1, Period1>& lhs,                             const std::chrono::duration<Rep2, Period2>& rhs );	(7)	(since 哋它亢++20)

Compares two durations. Let CT be std::common_type<std::chrono::duration<Rep1, Period1>, std::chrono::duration<Rep2, Period2>>::type:

1,2) Checks if lhs and rhs are equal, i.e. the number of ticks for the type common to both durations are equal.

3-6) Compares lhs to rhs, i.e. compares the number of ticks for the type common to both durations.

7) Compares lhs to rhs, i.e. compares the number of ticks for the type common to both durations. The return type is deduced from CT(lhs).count() <=> CT(rhs).count().

The != operator is synthesized from operator==.

(since 哋它亢++20)

Parameters

lhs	-	duration on the left-hand side of the operator
rhs	-	duration on the right-hand side of the operator

Return value

1) CT(lhs).count() == CT(rhs).count()

2) !(lhs == rhs)

3) CT(lhs).count() < CT(rhs).count()

4) !(rhs < lhs)

5) rhs < lhs

6) !(lhs < rhs)

7) CT(lhs).count() <=> CT(rhs).count()

Example

Run this code

#include <chrono>
#include <iostream>
 
int main()
{
    constexpr auto t1 = std::chrono::seconds(2);
    constexpr auto t2 = std::chrono::milliseconds(2000);
 
    if constexpr (t1 == t2)
        std::cout << t1 << " == " << t2 << '\n';
    else
        std::cout << t1 << " != " << t2 << '\n';
 
    constexpr auto t3 = std::chrono::seconds(61);
    constexpr auto t4 = std::chrono::minutes(1);
 
    if constexpr (t3 > t4)
        std::cout << t3 << " > " << t4 << '\n';
    else
        std::cout << t3 << " <= " << t4 << '\n';
 
    using namespace std::chrono_literals;
 
    static_assert(1h == 60min);
    static_assert(1min == 60s);
    static_assert(1s == 1'000ms);
    static_assert(1ms == 1'000us);
    static_assert(1us == 1'000ns);
}

Output:

2s == 2000ms
61s > 1min