23 Containers library [containers]

23.3 Sequence containers [sequences]

23.3.4 Class template forward_list [forwardlist] forward_list iterators [forwardlist.iter]

iterator before_begin() noexcept; const_iterator before_begin() const noexcept; const_iterator cbefore_begin() const noexcept;

Returns: A non-dereferenceable iterator that, when incremented, is equal to the iterator returned by begin().

Effects: cbefore_begin() is equivalent to const_cast<forward_list const&>(*this).before_begin().

Remarks: before_begin() == end() shall equal false.