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

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.

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