std::forward_list<T,Allocator>::before_begin,cbefore_begin (3) - Linux Man Pages

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

NAME

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


end_ returns an iterator to the end
cend (public member function)