std::forward_list<T,Allocator>::before_begin, cbefore_begin

iterator before_begin() noexcept;

const_iterator before_begin() const noexcept;

const_iterator cbefore_begin() const noexcept;

Returns an iterator to the element before the first element of the container. This element acts as a placeholder, attempting to access it results in undefined behavior. The only usage cases are in functions insert_after(), emplace_after(), erase_after(), splice_after() and the increment operator: incrementing the before-begin iterator gives exactly the same iterator as obtained from begin()/cbegin().

Parameters

(none).

Return value

Iterator to the element before the first element.

Complexity

Constant.

See also