std::forward_list::before_begin, cbefore_begin
From cppreference.com
< cpp | container | forward list
| iterator before_begin() noexcept; |
(since C++11) | |
| const_iterator before_begin() const noexcept; |
(since C++11) | |
| const_iterator cbefore_begin() const noexcept; |
(since C++11) | |
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
| returns an iterator to the beginning (public member function) | |
| returns an iterator to the end (public member function) |