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std::forward_list::before_begin,cbefore_begin(3) C++ Standard Libary std::forward_list::before_begin,cbefore_begin(3)

NAME

std::forward_list::before_begin,cbefore_begin - std::forward_list::before_begin,cbefore_begin

Synopsis


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


begin returns an iterator to the beginning
cbegin (public member function)
(C++11)
end returns an iterator to the end
cend (public member function)
(C++11)

2022.07.31 http://cppreference.com