std::forward_list (3) - Linux Manuals

std::forward_list: std::forward_list

NAME

std::forward_list - std::forward_list

Synopsis

Defined in header <forward_list>
template<
class T, (1) (since C++11)
class Allocator = std::allocator<T>
> class forward_list;
namespace pmr {
template <class T> (2) (since C++17)
using forward_list = std::forward_list<T, std::pmr::polymorphic_allocator<T>>;
}

std::forward_list is a container that supports fast insertion and removal of elements from anywhere in the container. Fast random access is not supported. It is implemented as a singly-linked list and essentially does not have any overhead compared to its implementation in C. Compared to std::list this container provides more space efficient storage when bidirectional iteration is not needed.
Adding, removing and moving the elements within the list, or across several lists, does not invalidate the iterators currently referring to other elements in the list. However, an iterator or reference referring to an element is invalidated when the corresponding element is removed (via erase_after) from the list.
std::forward_list meets the requirements of Container (except for the size member function and that operator=='s complexity is always linear), AllocatorAwareContainer and SequenceContainer.

Template parameters

            The type of the elements.

T - The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type is a complete type and meets the requirements of Erasable, but many member functions impose stricter requirements. (until C++17)
            The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type meets the requirements of Erasable, but many member functions impose stricter requirements. This container (but not its members) can be instantiated with an incomplete element type if the allocator satisfies the allocator_completeness_requirements. (since C++17)

Allocator - An allocator that is used to acquire/release memory and to construct/destroy the elements in that memory. The type must meet the requirements of Allocator. The behavior is undefined if Allocator::value_type is not the same as T.

Member types

Member type Definition
value_type T
allocator_type Allocator
size_type Unsigned integer type (usually std::size_t)
difference_type Signed integer type (usually std::ptrdiff_t)
reference value_type&
const_reference const value_type&
pointer std::allocator_traits<Allocator>::pointer
const_pointer std::allocator_traits<Allocator>::const_pointer
iterator LegacyForwardIterator
const_iterator Constant LegacyForwardIterator

Member functions

              constructs the forward_list
constructor (public member function)
              destructs the forward_list
destructor (public member function)
              assigns values to the container
operator= (public member function)
              assigns values to the container
assign (public member function)
              returns the associated allocator
get_allocator (public member function)

Element access

              access the first element
front (public member function)

Iterators

              returns an iterator to the element before beginning
before_begin (public member function)
cbefore_begin

begin returns an iterator to the beginning
cbegin (public member function)

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

Capacity

              checks whether the container is empty
empty (public member function)
              returns the maximum possible number of elements
max_size (public member function)

Modifiers

              clears the contents
clear (public member function)
              inserts elements after an element
insert_after (public member function)
              constructs elements in-place after an element
emplace_after (public member function)
              erases an element after an element
erase_after (public member function)
              inserts an element to the beginning
push_front (public member function)
              constructs an element in-place at the beginning
emplace_front (public member function)
              removes the first element
pop_front (public member function)
              changes the number of elements stored
resize (public member function)
              swaps the contents
swap (public member function)

Operations

              merges two sorted lists
merge (public member function)
              moves elements from another forward_list
splice_after (public member function)
              removes elements satisfying specific criteria
remove (public member function)
remove_if
              reverses the order of the elements
reverse (public member function)
              removes consecutive duplicate elements
unique (public member function)
              sorts the elements
sort (public member function)

Non-member functions

operator==
operator!= lexicographically compares the values in the forward_list
operator< (function template)
operator<=
operator>
operator>=

std::swap(std::forward_list) specializes the std::swap algorithm
                             (function template)
(C++11)

erase(std::forward_list) Erases all elements satisfying specific criteria
erase_if(std::forward_list) (function template)

(C++20)

Deduction_guides(since C++17)