std::literals::chrono_literals::operator""d

 

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chrono I/O
parse (C++20)
C-style date and time

 

std::chrono::day

Member functions

day::day

day::operator++day::operator--

day::operator+=day::operator-=

day::operator unsigned

day::ok

Nonmember functions

operator==operator<=>

operator+operator-

operator<<

from_stream

operator""d

Helper classes

formatter<std::chrono::day>

hash<std::chrono::day> (C++26)

 

Defined in header <chrono>
constexpr std::chrono::day operator ""d( unsigned long long d ) noexcept;		(since C++20)

Forms a std::chrono::day literal representing a day of the month in the calendar.

Parameters

d

-

the day value

Return value

A std::chrono::day storing d. If d > 255, the stored value is unspecified.

Possible implementation

constexpr std::chrono::day operator ""d(unsigned long long d) noexcept { return std::chrono::day(d); }

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.

Example

Run this code

#include <chrono>
#include <iostream>
 
int main()
{
    using namespace std::literals::chrono_literals;
 
    std::cout << static_cast<unsigned>(42d) << '\t' << 42d << '\n'
              << static_cast<unsigned>(256d) << '\t' << 256d << '\n' // unspecified
              << static_cast<unsigned>(298d) << '\t' << 298d << '\n'; // unspecified
}

Possible output:

42      42 is not a valid day
0       00 is not a valid day
42      42 is not a valid day

See also

(constructor)	constructs a day (public member function of std::chrono::day)
operator unsigned	retrieves the stored day value (public member function of std::chrono::day)