Perform a three-way comparison of the specified lhs and the specified rhs objects by using the comparison operators of t_LHS and t_RHS; return the result of that comparison. This function can be called in constant expressions only if t_LHS is not allocator-aware.
Declared in <bslstl_optional.h>
template<
class t_LHS,
three_way_comparable_with<t_LHS> t_RHS>
constexpr
compare_three_way_result_t<t_LHS, t_RHS>
operator<=>(
bsl::optional<t_LHS> const& lhs,
std::optional<t_RHS> const& rhs);