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

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)

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