[ ` <mdspan> ` ](/w/cpp/header/mdspan "cpp/header/mdspan") |  (C++23)  |  [ P0009R18 ](https://wg21.link/P0009R18)   
[ P2599R2 ](https://wg21.link/P2599R2)  
[ P2604R0 ](https://wg21.link/P2604R0)  
[ P2613R1 ](https://wg21.link/P2613R1)  
` __cpp_lib_memory_resource ` |  [ std::pmr::memory_resource ](/w/cpp/memory/memory_resource "cpp/memory/memory resource") |  201603L  |  [ ` <memory_resource> ` ](/w/cpp/header/memory_resource "cpp/header/memory resource") |  (C++17)  |  [ P0220R1 ](https://wg21.link/P0220R1)  
` __cpp_lib_modules ` |  [ Standard library modules ](/w/cpp/standard_library#Importing_modules "cpp/standard library") ` std ` and ` std.compat ` |  202207L  |  |  (C++23)  |  [ P2465R3 ](https://wg21.link/P2465R3)  
` __cpp_lib_move_iterator_  concept ` |  Make  [ std::move_iterator<T*> ](/w/cpp/iterator/move_iterator "cpp/iterator/move iterator") a random access iterator  |  202207L  |  [ ` <iterator> ` ](/w/cpp/header/iterator "cpp/header/iterator") |  (C++23)  |  [ P2520R0 ](https://wg21.link/P2520R0)  
` __cpp_lib_move_only_function ` |  std::move_only_function  |  202110L  |  [ ` <functional> ` ](/w/cpp/header/functional "cpp/header/functional") |  (C++23)  |  [ P0288R9 ](https://wg21.link/P0288R9)  
` __cpp_lib_node_extract ` |  Splicing maps and sets (  [ std::map::extract ](/w/cpp/container/map/extract "cpp/container/map/extract") ,  [ std::map::merge ](/w/cpp/container/map/merge "cpp/container/map/merge") , [ ` std::map::insert(node_type) ` ](/w/cpp/container/map/insert "cpp/container/map/insert") , etc)  |  201606L  |  [ ` <map> ` ](/w/cpp/header/map "cpp/header/map") [ ` <set> ` ](/w/cpp/header/set "cpp/header/set") [ ` <unordered_map> ` ](/w/cpp/header/unordered_map "cpp/header/unordered map") [ ` <unordered_set> ` ](/w/cpp/header/unordered_set "cpp/header/unordered set") |  (C++17)  |  [ P0083R3 ](https://wg21.link/P0083R3)  
` __cpp_lib_nonmember_  container_access ` |  [ std::size() ](/w/cpp/iterator/size "cpp/iterator/size") ,  [ std::data() ](/w/cpp/iterator/data "cpp/iterator/data") and  [ std::empty() ](/w/cpp/iterator/empty "cpp/iterator/empty") |  201411L  |  [ ` <iterator> ` ](/w/cpp/header/iterator "cpp/header/iterator") [ ` <array> ` ](/w/cpp/header/array "cpp/header/array") [ ` <deque> ` ](/w/cpp/header/deque "cpp/header/deque") [ ` <forward_list> ` ](/w/cpp/header/forward_list "cpp/header/forward list") [ ` <list> ` ](/w/cpp/header/list "cpp/header/list") [ ` <map> ` ](/w/cpp/header/map "cpp/header/map") [ ` <regex> ` ](/w/cpp/header/regex "cpp/header/regex") [ ` <set> ` ](/w/cpp/header/set "cpp/header/set") [ ` <string> ` ](/w/cpp/header/string "cpp/header/string") [ ` <unordered_map> ` ](/w/cpp/header/unordered_map "cpp/header/unordered map") [ ` <unordered_set> ` ](/w/cpp/header/unordered_set "cpp/header/unordered set") [ ` <vector> ` ](/w/cpp/header/vector "cpp/header/vector") |  (C++17)  |  [ N4280 ](https://wg21.link/N4280)  
` __cpp_lib_not_fn ` |  [ std::not_fn() ](/w/cpp/utility/functional/not_fn "cpp/utility/functional/not fn") |  201603L  |  [ ` <functional> ` ](/w/cpp/header/functional "cpp/header/functional") |  (C++17)  |  [ P0005R4 ](https://wg21.link/P0005R4)  
Allow passing callable objects as non-type template arguments to  [ std::not_fn ](/w/cpp/utility/functional/not_fn "cpp/utility/functional/not fn") |  202306L  |  [ ` <functional> ` ](/w/cpp/header/functional "cpp/header/functional") |  (C++26)  |  [ P2714R1 ](https://wg21.link/P2714R1)  
` __cpp_lib_null_iterators ` |  Null [ LegacyForwardIterator  s ](/w/cpp/named_req/ForwardIterator "cpp/named req/ForwardIterator") |  201304L  |  [ ` <iterator> ` ](/w/cpp/header/iterator "cpp/header/iterator") |  (C++14)  |  [ N3644 ](https://wg21.link/N3644)  
` __cpp_lib_optional ` |  [ std::optional ](/w/cpp/utility/optional "cpp/utility/optional") |  201606L  |  [ ` <optional> ` ](/w/cpp/header/optional "cpp/header/optional") |  (C++17)  |  [ P0220R1 ](https://wg21.link/P0220R1)   
[ P0032R3 ](https://wg21.link/P0032R3)  
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