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 a time_point.

constexpr
date(
    time_point tp);

Strong guarantee. Throws on invalid input.

Type	Thrown On
`std::out_of_range`	If the resulting `date` would be out of the [`min_date`, `max_date`] range.