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

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< cpp‎ | chrono

Defined in header `<chrono>` |  |
constexpr std::chrono::seconds operator""s( unsigned long long secs ); | (1) | (since C++14)
constexpr std::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

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.

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 <chrono>
    #include <iostream>

    int main()
    {
        using namespace std::chrono_literals;

        std::chrono::seconds halfmin = 30s;
        std::cout << "Half a minute is " << halfmin.count() << " seconds"
            " (" << halfmin << ").\n"
            "A minute and a second is " << (1min + 1s).count() << " seconds.\n";

        std::chrono::duration moment = 0.1s;
        std::cout << "A moment is " << moment.count() << " seconds"
            " (" << moment << ").\n"
            "And thrice as much is " << (moment + 0.2s).count() << " seconds.\n";
    }

Output:

    Half a minute is 30 seconds (30s).
    A minute and a second is 61 seconds.
    A moment is 0.1 seconds (0.1s).
    And thrice as much is 0.3 seconds.

### See also

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

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