Standard library header <new>

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;