Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Constructs a date from its year, month and date components.

constexpr
date(
    std::uint16_t year,
    std::uint8_t month,
    std::uint8_t day);

Component values that yield invalid dates (like zero or out-of-range values) are allowed, resulting in an object with this->valid() == false.

No-throw guarantee.