std::literals::chrono_literals::operator""us
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std::chrono::duration
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operator""us
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Helper classes
Defined in header
<chrono>
constexpr std::chrono::microseconds
operator""us( unsigned long long us );
(1)
(since C++14)
operator""us( unsigned long long us );
constexpr std::chrono::duration </*unspecified*/, std::micro >
operator""us( long double us );
(2)
(since C++14)
operator""us( long double us );
Forms a std::chrono::duration literal representing microseconds.
1) Integer literal, returns exactly std::chrono::microseconds (us).
2) Floating-point literal, returns a floating-point duration equivalent to std::chrono::microseconds .
[edit] Parameters
us
-
the number of microseconds
[edit] Return value
The std::chrono::duration literal.
[edit] Possible implementation
constexpr std::chrono::microseconds operator""us(unsigned long long us) { return std::chrono::microseconds (us); } constexpr std::chrono::duration <long double, std::micro > operator""us(long double us) { return std::chrono::duration <long double, std::micro >(us); }
[edit] 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.
[edit] Example
Run this code
#include <chrono> #include <iostream> int main() { using namespace std::chrono_literals; auto d1 = 250us; std::chrono::microseconds d2 = 1ms; std::cout << d1 << " = " << d1.count() << " microseconds\n" << 1ms << " = " << d2.count() << " microseconds\n"; }
Output:
250us = 250 microseconds 1ms = 1000 microseconds