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std::literals::chrono_literals::operator""ns(3) | C++ Standard Libary | std::literals::chrono_literals::operator""ns(3) |
NAME¶
std::literals::chrono_literals::operator""ns - std::literals::chrono_literals::operator""ns
Synopsis¶
Defined in header <chrono>
constexpr std::chrono::nanoseconds operator "" ns(unsigned long
(1) (since C++14)
long nsec);
constexpr std::chrono::duration</*unspecified*/, (2) (since
C++14)
std::nano> operator "" ns(long double nsec);
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¶
These operators are declared in the namespace
std::literals::chrono_literals, where
both literals and chrono_literals are inline namespaces. Access to these
operators
can be gained with using namespace std::literals, using namespace
std::chrono_literals, and 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>)
2022.07.31 | http://cppreference.com |