NAME¶

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

Synopsis¶

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

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>)