std::optional<T>::or_else
From cppreference.com
| template< class F > constexpr optional or_else( F&& f ) const&; |
(1) | (since C++23) |
| template< class F > constexpr optional or_else( F&& f ) &&; |
(2) | (since C++23) |
Returns *this if it contains a value. Otherwise, returns the result of f.
The program is ill-formed if std::remove_cvref_t<std::invoke_result_t<F>> is not same as std::optional<T>.
1) Equivalent to return *this ? *this : std::forward<F>(f)();. This overload participates in overload resolution only if both std::copy_constructible<T> and std::invocable<F> are modeled.
2) Equivalent to return *this ? std::move(*this) : std::forward<F>(f)();. This overload participates in overload resolution only if both std::move_constructible<T> and std::invocable<F> are modeled.
Contents |
[edit] Parameters
| f | - | a function or Callable object that returns an |