std::list<T,Allocator>::list

 

C++

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Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Iterator invalidation

Member function table

Non-member function table

 

std::list

Member functions

list::list

list::~list

list::operator=

list::assign

list::assign_range (C++23)

list::get_allocator

Element access

list::front

list::back

Iterators

list::beginlist::cbegin (C++11)

list::endlist::cend (C++11)

list::rbeginlist::crbegin (C++11)

list::rendlist::crend (C++11)

Capacity

list::empty

list::size

list::max_size

Modifiers

list::clear

list::insert

list::insert_range (C++23)

list::emplace (C++11)

list::erase

list::push_front

list::emplace_front (C++11)

list::prepend_range (C++23)

list::pop_front

list::push_back

list::emplace_back (C++11)

list::append_range (C++23)

list::pop_back

list::resize

list::swap

Operations

list::merge

list::splice

list::removelist::remove_if

list::reverse

list::unique

list::sort

Non-member functions

std::swap

eraseerase_if (C++20)(C++20)

operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Deduction guides(C++17)

 

list();	(1)
explicit list( const Allocator& alloc );	(2)
	(3)
explicit list( size_type count,                const T& value = T(),                const Allocator& alloc = Allocator() );			(until C++11)
list( size_type count,                const T& value,                const Allocator& alloc = Allocator() );			(since C++11)
		(4)
explicit list( size_type count );				(since C++11) (until C++14)
explicit list( size_type count,                const Allocator& alloc = Allocator() );				(since C++14)
template< class InputIt > list( InputIt first, InputIt last,       const Allocator& alloc = Allocator() );			(5)
list( const list& other );			(6)
list( const list& other, const Allocator& alloc );			(7)	(since C++11)
list( list&& other );			(8)	(since C++11)
list( list&& other, const Allocator& alloc );			(9)	(since C++11)
list( std::initializer_list<T> init,       const Allocator& alloc = Allocator() );			(10)	(since C++11)
template< container-compatible-range<T> R > list( std::from_range_t, R&& rg,       const Allocator& alloc = Allocator() );			(11)	(since C++23)

Constructs a new container from a variety of data sources, optionally using a user supplied allocator alloc.

1) Default constructor. Constructs an empty container with a default-constructed allocator.

2) Constructs an empty container with the given allocator alloc.

3) Constructs the container with count copies of elements with value value.

4) Constructs the container with count default-inserted instances of T. No copies are made.

5) Constructs the container with the contents of the range [first, last).

This constructor has the same effect as list(static_cast<size_type>(first), static_cast<value_type>(last), a) if InputIt is an integral type.	(until C++11)
This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator, to avoid ambiguity with the overload (3).	(since C++11)

6) Copy constructor. Constructs the container with the copy of the contents of other.

The allocator is obtained as if by calling std::allocator_traits<allocator_type>::select_on_container_copy_construction(     other.get_allocator()).

(since C++11)

7) Constructs the container with the copy of the contents of other, using alloc as the allocator.

During class template argument deduction, only the first argument contributes to the deduction of the container's Allocator template parameter.

(since C++23)

8) Move constructor. Constructs the container with the contents of other using move semantics. Allocator is obtained by move-construction from the allocator belonging to other.

9) Allocator-extended move constructor. Using alloc as the allocator for the new container, moving the contents from other; if alloc != other.get_allocator(), this results in an element-wise move.

During class template argument deduction, only the first argument contributes to the deduction of the container's Allocator template parameter.

(since C++23)

10) Constructs the container with the contents of the initializer list init.

11) Constructs the container with the contents of the range rg.

Parameters

alloc	-	allocator to use for all memory allocations of this container
count	-	the size of the container
value	-	the value to initialize elements of the container with
first, last	-	the range [first, last) to copy the elements from
other	-	another container to be used as source to initialize the elements of the container with
init	-	initializer list to initialize the elements of the container with
rg	-	a container compatible range, that is, an input_range whose elements are convertible to T

Complexity

1,2) Constant.

3,4) Linear in count.

5) Linear in distance between first and last.

6,7) Linear in size of other.

8) Constant.

9) Linear if alloc != other.get_allocator(), otherwise constant.

10) Linear in size of init.

11) Linear in ranges::distance(rg).

Exceptions

Calls to Allocator::allocate may throw.

Notes

After container move construction (overload (8)), references, pointers, and iterators (other than the end iterator) to other remain valid, but refer to elements that are now in *this. The current standard makes this guarantee via the blanket statement in [container.reqmts]/67, and a more direct guarantee is under consideration via LWG issue 2321.

Feature-test macro	Value	Std	Feature
__cpp_lib_containers_ranges	202202L	(C++23)	Ranges-aware construction and insertion; overload (11)

Example

Run this code

#include <iostream>
#include <string>
#include <list>
 
template<typename T>
std::ostream& operator<<(std::ostream& s, const std::list<T>& v)
{
    s.put('{');
    for (char comma[]{'\0', ' ', '\0'}; const auto& e : v)
        s << comma << e, comma[0] = ',';
    return s << "}\n";
}
 
int main()
{
    // C++11 initializer list syntax:
    std::list<std::string> words1{"the", "frogurt", "is", "also", "cursed"};
    std::cout << "1: " << words1;
 
    // words2 == words1
    std::list<std::string> words2(words1.begin(), words1.end());
    std::cout << "2: " << words2;
 
    // words3 == words1
    std::list<std::string> words3(words1);
    std::cout << "3: " << words3;
 
    // words4 is {"Mo", "Mo", "Mo", "Mo", "Mo"}
    std::list<std::string> words4(5, "Mo");
    std::cout << "4: " << words4;
 
    auto const rg = {"cat", "cow", "crow"};
#ifdef __cpp_lib_containers_ranges
    std::list<std::string> words5(std::from_range, rg); // overload (11)
#else
    std::list<std::string> words5(rg.begin(), rg.end()); // overload (5)
#endif
    std::cout << "5: " << words5;
}

Output:

1: {the, frogurt, is, also, cursed}
2: {the, frogurt, is, also, cursed}
3: {the, frogurt, is, also, cursed}
4: {Mo, Mo, Mo, Mo, Mo}
5: {cat, cow, crow}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 868	C++98	for overload (4), the elements in the container were default constructed	they are value-initialized
LWG 2193	C++11	the default constructor is explicit	made non-explicit

See also

assign	assigns values to the container (public member function)
operator=	assigns values to the container (public member function)