std::literals::chrono_literals::operator""s

Defined in header `<chrono>`
constexpr chrono::seconds operator "" s(unsigned long long secs);	(1)	(since C++14)
constexpr chrono::duration</unspecified/> operator "" s(long double secs);	(2)	(since C++14)

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

1) integer literal, returns exactly std::chrono::seconds(secs)

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

Parameters

secs

-

the number of seconds

Return value

The std::chrono::duration literal.

Possible implementation

constexpr std::chrono::seconds operator ""s(unsigned long long s)
{
    return std::chrono::seconds(s);
}
constexpr std::chrono::duration<long double> operator ""s(long double s)
{
    return std::chrono::duration<long double>(s);
}

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 duration classes, the duration literal operators become visible as well.

std::string also defines operator""s, to represent literal objects of type std::string, but it is a string literal: 10s is ten seconds, but "10"s is a two-character string.

Example

Run this code

#include <iostream>
#include <chrono>
 
int main()
{
    using namespace std::chrono_literals;
    auto halfmin = 30s;
    std::cout << "half a minute is " << halfmin.count() << " seconds\n"
              << "a minute and a half is " << (1min + 30s).count() << " seconds\n";
}

Output:

half a minute is 30 seconds
a minute and a half is 90 seconds

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