NAME

std::nullopt - std::nullopt

Synopsis

Defined in header <optional>
inline constexpr nullopt_t nullopt{/*unspecified*/}; (since C++17)

std::nullopt is a constant of type std::nullopt_t that is used to indicate optional
type with uninitialized state.

See also

nullopt_t indicator of optional type with uninitialized state
(C++17) (class)