Standard library header <new>

 

C++

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Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Standard library headers

Language support <cfloat> <climits> <compare> (C++20) <contracts> (C++26) <coroutine> (C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint> (C++11) <cstdlib> <exception> <initializer_list> (C++11)   <limits> <new> <source_location> (C++20) <stdfloat> (C++23) <typeinfo> <version> (C++20) Concepts <concepts> (C++20) Diagnostics <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) Memory management <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) Metaprogramming <meta> (C++26) <ratio> (C++11) <type_traits> (C++11)

General utilities <any> (C++17) <bitset> <bit> (C++20) <charconv> (C++17) <expected> (C++23) <format> (C++20) <functional> <optional> (C++17) <stdbit.h> (C++26) <tuple> (C++11) <typeindex> (C++11) <utility> <variant> (C++17) Containers <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <hive> (C++26) <inplace_vector> (C++26)   <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> Iterators <iterator> Ranges <generator> (C++23) <ranges> (C++20)

Algorithms <algorithm> <numeric> Strings <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> Text processing <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)   Numerics <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <simd> (C++26) <stdckdint.h> (C++26) <valarray> Time <chrono> (C++11) <ctime> C compatibility <ccomplex> (C++11/17/20*) <ciso646> (until C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

Input/output <cinttypes> (C++11) <cstdio> <filesystem> (C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print> (C++23) <spanstream> (C++23) <sstream> <streambuf> <strstream> (C++98/26*) <syncstream> (C++20) Concurrency support <atomic> (C++11) <barrier> (C++20) <condition_variable> (C++11) <future> (C++11) <hazard_pointer> (C++26) <latch> (C++20) <mutex> (C++11) <rcu> (C++26) <semaphore> (C++20) <shared_mutex> (C++14) <stdatomic.h> (C++23) <stop_token> (C++20) <thread> (C++11) Execution support <execution> (C++17)

 

This header is part of the dynamic memory management library, in particular provides low level memory management features.

Classes
bad_alloc	exception thrown when memory allocation fails (class)
bad_array_new_length (C++11)	exception thrown on allocation of array with invalid length (class)
align_val_t (C++17)	type used to pass alignment to alignment-aware allocation and deallocation functions (enum)
Types
new_handler	function pointer type of the new handler (typedef)
Tags
nothrownothrow_t	a tag used to select a non-throwing allocation function (tag)
destroying_deletedestroying_delete_t (C++20)	a tag used to select destroying-delete overloads of operator delete (tag)
Constants
hardware_destructive_interference_sizehardware_constructive_interference_size (C++17)	min offset to avoid false sharing max offset to promote true sharing (constant)
Functions
operator newoperator new[]	allocation functions (function)
operator deleteoperator delete[]	deallocation functions (function)
get_new_handler (C++11)	obtains the current new handler (function)
set_new_handler	registers a new handler (function)
launder (C++17)	pointer optimization barrier (function template)

Synopsis

// all freestanding
namespace std {
  // storage allocation errors
  class bad_alloc;
  class bad_array_new_length;

  struct destroying_delete_t
  {
    explicit destroying_delete_t() = default;
  };
  inline constexpr destroying_delete_t destroying_delete{};

  // global operator new control
  enum class align_val_t : size_t
  {
  };

  struct nothrow_t
  {
    explicit nothrow_t() = default;
  };
  extern const nothrow_t nothrow;

  using new_handler = void (*)();
  new_handler get_new_handler() noexcept;
  new_handler set_new_handler(new_handler new_p) noexcept;

  // pointer optimization barrier
  template<class T> constexpr T* launder(T* p) noexcept;

  // hardware interference size
  inline constexpr size_t hardware_destructive_interference_size =
    /* implementation-defined */;
  inline constexpr size_t hardware_constructive_interference_size =
    /* implementation-defined */;
}

// storage allocation and deallocation
void*
operator new(std::size_t size);
void*
operator new(std::size_t size, std::align_val_t alignment);
void*
operator new(std::size_t size, const std::nothrow_t&) noexcept;
void*
operator new(std::size_t size,
             std::align_val_t alignment,
             const std::nothrow_t&) noexcept;

void
operator delete(void* ptr) noexcept;
void
operator delete(void* ptr, std::size_t size) noexcept;
void
operator delete(void* ptr, std::align_val_t alignment) noexcept;
void
operator delete(void* ptr, std::size_t size, std::align_val_t alignment) noexcept;
void
operator delete(void* ptr, const std::nothrow_t&) noexcept;
void
operator delete(void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept;

void*
operator new[](std::size_t size);
void*
operator new[](std::size_t size, std::align_val_t alignment);
void*
operator new[](std::size_t size, const std::nothrow_t&) noexcept;
void*
operator new[](std::size_t size,
               std::align_val_t alignment,
               const std::nothrow_t&) noexcept;

void
operator delete[](void* ptr) noexcept;
void
operator delete[](void* ptr, std::size_t size) noexcept;
void
operator delete[](void* ptr, std::align_val_t alignment) noexcept;
void
operator delete[](void* ptr, std::size_t size, std::align_val_t alignment) noexcept;
void
operator delete[](void* ptr, const std::nothrow_t&) noexcept;
void
operator delete[](void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept;

constexpr void*
operator new(std::size_t size, void* ptr) noexcept;
constexpr void*
operator new[](std::size_t size, void* ptr) noexcept;
constexpr void
operator delete(void* ptr, void*) noexcept;
constexpr void
operator delete[](void* ptr, void*) noexcept;