std::literals::chrono_literals::operator""ns

 

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

 

Defined in header <chrono>
constexpr std::chrono::nanoseconds operator ""ns( unsigned long long nsec );	(1)	(since C++14)
constexpr std::chrono::duration</*unspecified*/, std::nano>                                    operator ""ns( long double nsec );	(2)	(since C++14)

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

1) integer literal, returns exactly std::chrono::nanoseconds(nsec)

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

Parameters

nsec

-

the number of nanoseconds

Return value

The std::chrono::duration literal.

Possible implementation

constexpr std::chrono::nanoseconds operator ""ns(unsigned long long ns) { return std::chrono::nanoseconds(ns); } constexpr std::chrono::duration<long double, std::nano> operator ""ns(long double ns) { return std::chrono::duration<long double, std::nano>(ns); }

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 d1 = 250ns;
    std::chrono::nanoseconds d2 = 1us;
    std::cout << "250ns = " << d1.count() << " nanoseconds\n"
              << "1us = " << d2.count() << " nanoseconds\n";
}

Output:

250ns = 250 nanoseconds
1us = 1000 nanoseconds

See also

(constructor)

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