std::literals::chrono_literals::operator""h

 

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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)
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common_type treat_as_floating_point	duration_values formatter<std::chrono::duration> (C++20)

 

Defined in header <chrono>
constexpr std::chrono::hours operator ""h( unsigned long long hrs );	(1)	(since C++14)
constexpr std::chrono::duration</*unspecified*/, std::ratio<3600,1>>                              operator ""h( long double hrs );	(2)	(since C++14)

Forms a std::chrono::duration literal representing hours.

1) integer literal, returns exactly std::chrono::hours(hrs)

2) floating-point literal, returns a floating-point duration equivalent to std::chrono::hours

Parameters

hrs

-

the number of hours

Return value

The std::chrono::duration literal.

Possible implementation

constexpr std::chrono::hours operator ""h(unsigned long long h) { return std::chrono::hours(h); } constexpr std::chrono::duration<long double, ratio<3600,1>> operator ""h(long double h) { return std::chrono::duration<long double, std::ratio<3600,1>>(h); }

Notes

This operator is declared in the namespace std::literals::chrono_literals, where both literals and chrono_literals are inline namespaces. Access to this operator can be gained with:

• using namespace std::literals,
• using namespace std::chrono_literals, or
• using namespace std::literals::chrono_literals.

In addition, within the namespace std::chrono, the directive using namespace literals::chrono_literals; is provided by the standard library, so that if a programmer uses using namespace std::chrono; to gain access to the classes in the chrono library, the corresponding literal operators become visible as well.

Example

Run this code

#include <iostream>
#include <chrono>
 
int main()
{
    using namespace std::chrono_literals;
    auto day = 24h;
    auto halfhour = 0.5h;
    std::cout << "one day is " << day.count() << " hours\n"
              << "half an hour is " << halfhour.count() << " hours\n";
}

Output:

one day is 24 hours
half an hour is 0.5 hours

See also

(constructor)

constructs new duration (public member function of std::chrono::duration<Rep,Period>)