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Standard library header <atomic> (C++11)

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Standard library headers
 

This header is part of the concurrency support library.

Contents

Classes

(C++11)
 atomic class template and specializations for bool, integral, floating-point,(since C++20) and pointer types
(class template) [edit]
(C++20)
 provides atomic operations on non-atomic objects
(class template) [edit]
(C++11)
 the lock-free boolean atomic type
(class) [edit]
(C++11)
 defines memory ordering constraints for the given atomic operation
(enum) [edit]
(C++11)
 std::atomic<bool>
(typedef) [edit]
(C++11)
 std::atomic<char>
(typedef) [edit]
(C++11)
 std::atomic<signed char>
(typedef) [edit]
(C++11)
 std::atomic<unsigned char>
(typedef) [edit]
(C++11)
 std::atomic<short>
(typedef) [edit]
(C++11)
 std::atomic<unsigned short>
(typedef) [edit]
(C++11)
 std::atomic<int>
(typedef) [edit]
(C++11)
 std::atomic<unsigned int>
(typedef) [edit]
(C++11)
 std::atomic<long>
(typedef) [edit]
(C++11)
 std::atomic<unsigned long>
(typedef) [edit]
(C++11)
 std::atomic<long long>
(typedef) [edit]
(C++11)
 std::atomic<unsigned long long>
(typedef) [edit]
(C++20)
 std::atomic<char8_t>
(typedef) [edit]
(C++11)
 std::atomic<char16_t>
(typedef) [edit]
(C++11)
 std::atomic<char32_t>
(typedef) [edit]
(C++11)
 std::atomic<wchar_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::int8_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::uint8_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::int16_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::uint16_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::int32_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::uint32_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::int64_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::uint64_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_least8_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_least8_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_least16_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_least16_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_least32_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_least32_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_least64_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_least64_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_fast8_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_fast8_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_fast16_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_fast16_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_fast32_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_fast32_t>
(typedef) [edit]
(C++11)
 std::atomic<std::int_fast64_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uint_fast64_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::intptr_t>
(typedef) [edit]
(C++11)(optional)
 std::atomic<std::uintptr_t>
(typedef) [edit]
(C++11)
 std::atomic<std::size_t>
(typedef) [edit]
(C++11)
 std::atomic<std::ptrdiff_t>
(typedef) [edit]
(C++11)
 std::atomic<std::intmax_t>
(typedef) [edit]
(C++11)
 std::atomic<std::uintmax_t>
(typedef) [edit]
(C++20)
 a signed integral atomic type that is lock-free and for which waiting/notifying is most efficient
(typedef) [edit]
(C++20)
 an unsigned integral atomic type that is lock-free and for which waiting/notifying is most efficient
(typedef) [edit]

Functions

(C++11)
 checks if the atomic type's operations are lock-free
(function template) [edit]
(C++11)(C++11)
 atomically replaces the value of the atomic object with a non-atomic argument
(function template) [edit]
(C++11)(C++11)
 atomically obtains the value stored in an atomic object
(function template) [edit]
(C++11)(C++11)
 atomically replaces the value of the atomic object with non-atomic argument and returns the old value of the atomic
(function template) [edit]
(C++11)(C++11)(C++11)(C++11)
 atomically compares the value of the atomic object with non-atomic argument and performs atomic exchange if equal or atomic load if not
(function template) [edit]
(C++11)(C++11)
 adds a non-atomic value to an atomic object and obtains the previous value of the atomic
(function template) [edit]
(C++11)(C++11)
 subtracts a non-atomic value from an atomic object and obtains the previous value of the atomic
(function template) [edit]
(C++11)(C++11)
 replaces the atomic object with the result of bitwise AND with a non-atomic argument and obtains the previous value of the atomic
(function template) [edit]
(C++11)(C++11)
 replaces the atomic object with the result of bitwise OR with a non-atomic argument and obtains the previous value of the atomic
(function template) [edit]
(C++11)(C++11)
 replaces the atomic object with the result of bitwise XOR with a non-atomic argument and obtains the previous value of the atomic
(function template) [edit]
(C++26)(C++26)
 replaces the atomic object with the result of std::max with a non-atomic argument and obtains the previous value of the atomic
(function template) [edit]
(C++26)(C++26)
 replaces the atomic object with the result of std::min with a non-atomic argument and obtains the previous value of the atomic
(function template) [edit]
(C++20)(C++20)
 blocks the thread until notified and the atomic value changes
(function template) [edit]
(C++20)
 notifies a thread blocked in atomic_wait
(function template) [edit]
(C++20)
 notifies all threads blocked in atomic_wait
(function template) [edit]
(C++20)(C++20)
 atomically returns the value of the flag
(function) [edit]
(C++11)(C++11)
 atomically sets the flag to true and returns its previous value
(function) [edit]
(C++11)(C++11)
 atomically sets the value of the flag to false
(function) [edit]
(C++20)(C++20)
 blocks the thread until notified and the flag changes
(function) [edit]
(C++20)
 notifies a thread blocked in atomic_flag_wait
(function) [edit]
(C++20)
 notifies all threads blocked in atomic_flag_wait
(function) [edit]
(C++11)(deprecated in C++20)
 non-atomic initialization of a default-constructed atomic object
(function template) [edit]
(C++11)(deprecated in C++26)
 removes the specified object from the std::memory_order_consume dependency tree
(function template) [edit]
(C++11)
 generic memory order-dependent fence synchronization primitive
(function) [edit]
(C++11)
 fence between a thread and a signal handler executed in the same thread
(function) [edit]

Macros

(C++11)(deprecated in C++20)
 constant initialization of an atomic variable of static storage duration
(function macro) [edit]
(C++11)
 initializes an std::atomic_flag to false
(macro constant) [edit]

[edit] Synopsis

namespace std { /* until C++20: enum memory_order { memory_order_relaxed, memory_order_consume, memory_order_acquire, memory_order_release, memory_order_acq_rel, memory_order_seq_cst }; */   enum class memory_order : /* unspecified */; inline constexpr memory_order memory_order_relaxed = memory_order::relaxed; inline constexpr memory_order memory_order_consume = memory_order::consume; inline constexpr memory_order memory_order_acquire = memory_order::acquire; inline constexpr memory_order memory_order_release = memory_order::release; inline constexpr memory_order memory_order_acq_rel = memory_order::acq_rel; inline constexpr memory_order memory_order_seq_cst = memory_order::seq_cst;   template<class T> T kill_dependency(T y) noexcept;   // lock-free property #define ATOMIC_BOOL_LOCK_FREE /* unspecified */ #define ATOMIC_CHAR_LOCK_FREE /* unspecified */ #define ATOMIC_CHAR8_T_LOCK_FREE /* unspecified */ #define ATOMIC_CHAR16_T_LOCK_FREE /* unspecified */ #define ATOMIC_CHAR32_T_LOCK_FREE /* unspecified */ #define ATOMIC_WCHAR_T_LOCK_FREE /* unspecified */ #define ATOMIC_SHORT_LOCK_FREE /* unspecified */ #define ATOMIC_INT_LOCK_FREE /* unspecified */ #define ATOMIC_LONG_LOCK_FREE /* unspecified */ #define ATOMIC_LLONG_LOCK_FREE /* unspecified */ #define ATOMIC_POINTER_LOCK_FREE /* unspecified */   // class template atomic_ref template<class T> struct atomic_ref; // partial specialization for pointers template<class T> struct atomic_ref<T*>;   // class template atomic template<class T> struct atomic; // partial specialization for pointers template<class T> struct atomic<T*>;   // non-member functions template<class T> bool atomic_is_lock_free(const volatile atomic<T>*) noexcept; template<class T> bool atomic_is_lock_free(const atomic<T>*) noexcept; template<class T> void atomic_store(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> void atomic_store(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> void atomic_store_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> void atomic_store_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_load(const volatile atomic<T>*) noexcept; template<class T> T atomic_load(const atomic<T>*) noexcept; template<class T> T atomic_load_explicit(const volatile atomic<T>*, memory_order) noexcept; template<class T> T atomic_load_explicit(const atomic<T>*, memory_order) noexcept; template<class T> T atomic_exchange(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_exchange(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_exchange_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_exchange_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> bool atomic_compare_exchange_weak(volatile atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type) noexcept; template<class T> bool atomic_compare_exchange_weak(atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type) noexcept; template<class T> bool atomic_compare_exchange_strong(volatile atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type) noexcept; template<class T> bool atomic_compare_exchange_strong(atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type) noexcept; template<class T> bool atomic_compare_exchange_weak_explicit(volatile atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type, memory_order, memory_order) noexcept; template<class T> bool atomic_compare_exchange_weak_explicit(atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type, memory_order, memory_order) noexcept; template<class T> bool atomic_compare_exchange_strong_explicit(volatile atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type, memory_order, memory_order) noexcept; template<class T> bool atomic_compare_exchange_strong_explicit(atomic<T>*, typename atomic<T>::value_type*, typename atomic<T>::value_type, memory_order, memory_order) noexcept;   template<class T> T atomic_fetch_add(volatile atomic<T>*, typename atomic<T>::difference_type) noexcept; template<class T> T atomic_fetch_add(atomic<T>*, typename atomic<T>::difference_type) noexcept; template<class T> T atomic_fetch_add_explicit(volatile atomic<T>*, typename atomic<T>::difference_type, memory_order) noexcept; template<class T> T atomic_fetch_add_explicit(atomic<T>*, typename atomic<T>::difference_type, memory_order) noexcept; template<class T> T atomic_fetch_sub(volatile atomic<T>*, typename atomic<T>::difference_type) noexcept; template<class T> T atomic_fetch_sub(atomic<T>*, typename atomic<T>::difference_type) noexcept; template<class T> T atomic_fetch_sub_explicit(volatile atomic<T>*, typename atomic<T>::difference_type, memory_order) noexcept; template<class T> T atomic_fetch_sub_explicit(atomic<T>*, typename atomic<T>::difference_type, memory_order) noexcept; template<class T> T atomic_fetch_and(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_and(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_and_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_and_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_or(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_or(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_or_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_or_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_xor(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_xor(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_xor_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_xor_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_max(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_max(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_max_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_max_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_min(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_min(atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> T atomic_fetch_min_explicit(volatile atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept; template<class T> T atomic_fetch_min_explicit(atomic<T>*, typename atomic<T>::value_type, memory_order) noexcept;   template<class T> void atomic_wait(const volatile atomic<T>*, typename atomic<T>::value_type); template<class T> void atomic_wait(const atomic<T>*, typename atomic<T>::value_type); template<class T> void atomic_wait_explicit(const volatile atomic<T>*, typename atomic<T>::value_type, memory_order); template<class T> void atomic_wait_explicit(const atomic<T>*, typename atomic<T>::value_type, memory_order); template<class T> void atomic_notify_one(volatile atomic<T>*); template<class T> void atomic_notify_one(atomic<T>*); template<class T> void atomic_notify_all(volatile atomic<T>*); template<class T> void atomic_notify_all(atomic<T>*);   // type aliases using atomic_bool = atomic<bool>; using atomic_char = atomic<char>; using atomic_schar = atomic<signed char>; using atomic_uchar = atomic<unsigned char>; using atomic_short = atomic<short>; using atomic_ushort = atomic<unsigned short>; using atomic_int = atomic<int>; using atomic_uint = atomic<unsigned int>; using atomic_long = atomic<long>; using atomic_ulong = atomic<unsigned long>; using atomic_llong = atomic<long long>; using atomic_ullong = atomic<unsigned long long>; using atomic_char8_t = atomic<char8_t>; using atomic_char16_t = atomic<char16_t>; using atomic_char32_t = atomic<char32_t>; using atomic_wchar_t = atomic<wchar_t>;   using atomic_int8_t = atomic<int8_t>; using atomic_uint8_t = atomic<uint8_t>; using atomic_int16_t = atomic<int16_t>; using atomic_uint16_t = atomic<uint16_t>; using atomic_int32_t = atomic<int32_t>; using atomic_uint32_t = atomic<uint32_t>; using atomic_int64_t = atomic<int64_t>; using atomic_uint64_t = atomic<uint64_t>;   using atomic_int_least8_t = atomic<int_least8_t>; using atomic_uint_least8_t = atomic<uint_least8_t>; using atomic_int_least16_t = atomic<int_least16_t>; using atomic_uint_least16_t = atomic<uint_least16_t>; using atomic_int_least32_t = atomic<int_least32_t>; using atomic_uint_least32_t = atomic<uint_least32_t>; using atomic_int_least64_t = atomic<int_least64_t>; using atomic_uint_least64_t = atomic<uint_least64_t>;   using atomic_int_fast8_t = atomic<int_fast8_t>; using atomic_uint_fast8_t = atomic<uint_fast8_t>; using atomic_int_fast16_t = atomic<int_fast16_t>; using atomic_uint_fast16_t = atomic<uint_fast16_t>; using atomic_int_fast32_t = atomic<int_fast32_t>; using atomic_uint_fast32_t = atomic<uint_fast32_t>; using atomic_int_fast64_t = atomic<int_fast64_t>; using atomic_uint_fast64_t = atomic<uint_fast64_t>;   using atomic_intptr_t = atomic<intptr_t>; using atomic_uintptr_t = atomic<uintptr_t>; using atomic_size_t = atomic<size_t>; using atomic_ptrdiff_t = atomic<ptrdiff_t>; using atomic_intmax_t = atomic<intmax_t>; using atomic_uintmax_t = atomic<uintmax_t>;   using atomic_signed_lock_free = /* see description */; using atomic_unsigned_lock_free = /* see description */;   // flag type and operations struct atomic_flag;   bool atomic_flag_test(const volatile atomic_flag*) noexcept; bool atomic_flag_test(const atomic_flag*) noexcept; bool atomic_flag_test_explicit(const volatile atomic_flag*, memory_order) noexcept; bool atomic_flag_test_explicit(const atomic_flag*, memory_order) noexcept; bool atomic_flag_test_and_set(volatile atomic_flag*) noexcept; bool atomic_flag_test_and_set(atomic_flag*) noexcept; bool atomic_flag_test_and_set_explicit(volatile atomic_flag*, memory_order) noexcept; bool atomic_flag_test_and_set_explicit(atomic_flag*, memory_order) noexcept; void atomic_flag_clear(volatile atomic_flag*) noexcept; void atomic_flag_clear(atomic_flag*) noexcept; void atomic_flag_clear_explicit(volatile atomic_flag*, memory_order) noexcept; void atomic_flag_clear_explicit(atomic_flag*, memory_order) noexcept;   void atomic_flag_wait(const volatile atomic_flag*, bool) noexcept; void atomic_flag_wait(const atomic_flag*, bool) noexcept; void atomic_flag_wait_explicit(const volatile atomic_flag*, bool, memory_order) noexcept; void atomic_flag_wait_explicit(const atomic_flag*, bool, memory_order) noexcept; void atomic_flag_notify_one(volatile atomic_flag*) noexcept; void atomic_flag_notify_one(atomic_flag*) noexcept; void atomic_flag_notify_all(volatile atomic_flag*) noexcept; void atomic_flag_notify_all(atomic_flag*) noexcept;   // fences extern "C" void atomic_thread_fence(memory_order) noexcept; extern "C" void atomic_signal_fence(memory_order) noexcept; }   // deprecated namespace std { template<class T> void atomic_init(volatile atomic<T>*, typename atomic<T>::value_type) noexcept; template<class T> void atomic_init(atomic<T>*, typename atomic<T>::value_type) noexcept;   #define ATOMIC_VAR_INIT(value) /* see description */   #define ATOMIC_FLAG_INIT /* see description */ }

[edit] Class template std::atomic

namespace std { template<class T> struct atomic { using value_type = T;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const volatile noexcept; bool is_lock_free() const noexcept;   // operations on atomic types constexpr atomic() noexcept(is_nothrow_default_constructible_v<T>); constexpr atomic(T) noexcept; atomic(const atomic&) = delete; atomic& operator=(const atomic&) = delete; atomic& operator=(const atomic&) volatile = delete;   T load(memory_order = memory_order::seq_cst) const volatile noexcept; T load(memory_order = memory_order::seq_cst) const noexcept; operator T() const volatile noexcept; operator T() const noexcept; void store(T, memory_order = memory_order::seq_cst) volatile noexcept; void store(T, memory_order = memory_order::seq_cst) noexcept; T operator=(T) volatile noexcept; T operator=(T) noexcept;   T exchange(T, memory_order = memory_order::seq_cst) volatile noexcept; T exchange(T, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_weak(T&, T, memory_order, memory_order) volatile noexcept; bool compare_exchange_weak(T&, T, memory_order, memory_order) noexcept; bool compare_exchange_strong(T&, T, memory_order, memory_order) volatile noexcept; bool compare_exchange_strong(T&, T, memory_order, memory_order) noexcept; bool compare_exchange_weak(T&, T, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_weak(T&, T, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_strong(T&, T, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_strong(T&, T, memory_order = memory_order::seq_cst) noexcept;   void wait(T, memory_order = memory_order::seq_cst) const volatile noexcept; void wait(T, memory_order = memory_order::seq_cst) const noexcept; void notify_one() volatile noexcept; void notify_one() noexcept; void notify_all() volatile noexcept; void notify_all() noexcept; }; }

[edit] Specializations of std::atomic for integral types

namespace std { template<> struct atomic</* integral */> { using value_type = /* integral */; using difference_type = value_type;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const volatile noexcept; bool is_lock_free() const noexcept;   constexpr atomic() noexcept; constexpr atomic(/* integral */) noexcept; atomic(const atomic&) = delete; atomic& operator=(const atomic&) = delete; atomic& operator=(const atomic&) volatile = delete;   void store(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; void store(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ operator=(/* integral */) volatile noexcept; /* integral */ operator=(/* integral */) noexcept; /* integral */ load(memory_order = memory_order::seq_cst) const volatile noexcept; /* integral */ load(memory_order = memory_order::seq_cst) const noexcept; operator /* integral */() const volatile noexcept; operator /* integral */() const noexcept;   /* integral */ exchange(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ exchange(/* integral */, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order, memory_order) volatile noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order, memory_order) noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order, memory_order) volatile noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order, memory_order) noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order = memory_order::seq_cst) noexcept;   /* integral */ fetch_add(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_add(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_sub(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_sub(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_and(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_and(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_or(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_or(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_xor(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_xor(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_max(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_max(/* integral */, memory_order = memory_order::seq_cst) noexcept; /* integral */ fetch_min(/* integral */, memory_order = memory_order::seq_cst) volatile noexcept; /* integral */ fetch_min(/* integral */, memory_order = memory_order::seq_cst) noexcept;   /* integral */ operator++(int) volatile noexcept; /* integral */ operator++(int) noexcept; /* integral */ operator--(int) volatile noexcept; /* integral */ operator--(int) noexcept; /* integral */ operator++() volatile noexcept; /* integral */ operator++() noexcept; /* integral */ operator--() volatile noexcept; /* integral */ operator--() noexcept; /* integral */ operator+=(/* integral */) volatile noexcept; /* integral */ operator+=(/* integral */) noexcept; /* integral */ operator-=(/* integral */) volatile noexcept; /* integral */ operator-=(/* integral */) noexcept; /* integral */ operator&=(/* integral */) volatile noexcept; /* integral */ operator&=(/* integral */) noexcept; /* integral */ operator|=(/* integral */) volatile noexcept; /* integral */ operator|=(/* integral */) noexcept; /* integral */ operator^=(/* integral */) volatile noexcept; /* integral */ operator^=(/* integral */) noexcept;   void wait(/* integral */, memory_order = memory_order::seq_cst) const volatile noexcept; void wait(/* integral */, memory_order = memory_order::seq_cst) const noexcept; void notify_one() volatile noexcept; void notify_one() noexcept; void notify_all() volatile noexcept; void notify_all() noexcept; }; }

[edit] Specializations of std::atomic for floating-point types

namespace std { template<> struct atomic</* floating-point */> { using value_type = /* floating-point */; using difference_type = value_type;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const volatile noexcept; bool is_lock_free() const noexcept;   constexpr atomic() noexcept; constexpr atomic(/* floating-point */) noexcept; atomic(const atomic&) = delete; atomic& operator=(const atomic&) = delete; atomic& operator=(const atomic&) volatile = delete;   void store(/* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; void store(/* floating-point */, memory_order = memory_order_seq_cst) noexcept; /* floating-point */ operator=(/* floating-point */) volatile noexcept; /* floating-point */ operator=(/* floating-point */) noexcept; /* floating-point */ load(memory_order = memory_order_seq_cst) volatile noexcept; /* floating-point */ load(memory_order = memory_order_seq_cst) noexcept; operator /* floating-point */() volatile noexcept; operator /* floating-point */() noexcept;   /* floating-point */ exchange(/* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; /* floating-point */ exchange(/* floating-point */, memory_order = memory_order_seq_cst) noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order, memory_order) volatile noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order, memory_order) noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order, memory_order) volatile noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order, memory_order) noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) noexcept;   /* floating-point */ fetch_add(/* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; /* floating-point */ fetch_add(/* floating-point */, memory_order = memory_order_seq_cst) noexcept; /* floating-point */ fetch_sub(/* floating-point */, memory_order = memory_order_seq_cst) volatile noexcept; /* floating-point */ fetch_sub(/* floating-point */, memory_order = memory_order_seq_cst) noexcept;   /* floating-point */ operator+=(/* floating-point */) volatile noexcept; /* floating-point */ operator+=(/* floating-point */) noexcept; /* floating-point */ operator-=(/* floating-point */) volatile noexcept; /* floating-point */ operator-=(/* floating-point */) noexcept;   void wait(/* floating-point */, memory_order = memory_order::seq_cst) const volatile noexcept; void wait(/* floating-point */, memory_order = memory_order::seq_cst) const noexcept; void notify_one() volatile noexcept; void notify_one() noexcept; void notify_all() volatile noexcept; void notify_all() noexcept; }; }

[edit] Specializations of std::atomic for pointer types

namespace std { template<class T> struct atomic<T*> { using value_type = T*; using difference_type = ptrdiff_t;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const volatile noexcept; bool is_lock_free() const noexcept;   constexpr atomic() noexcept; constexpr atomic(T*) noexcept; atomic(const atomic&) = delete; atomic& operator=(const atomic&) = delete; atomic& operator=(const atomic&) volatile = delete;   void store(T*, memory_order = memory_order::seq_cst) volatile noexcept; void store(T*, memory_order = memory_order::seq_cst) noexcept; T* operator=(T*) volatile noexcept; T* operator=(T*) noexcept; T* load(memory_order = memory_order::seq_cst) const volatile noexcept; T* load(memory_order = memory_order::seq_cst) const noexcept; operator T*() const volatile noexcept; operator T*() const noexcept;   T* exchange(T*, memory_order = memory_order::seq_cst) volatile noexcept; T* exchange(T*, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_weak(T*&, T*, memory_order, memory_order) volatile noexcept; bool compare_exchange_weak(T*&, T*, memory_order, memory_order) noexcept; bool compare_exchange_strong(T*&, T*, memory_order, memory_order) volatile noexcept; bool compare_exchange_strong(T*&, T*, memory_order, memory_order) noexcept; bool compare_exchange_weak(T*&, T*, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_weak(T*&, T*, memory_order = memory_order::seq_cst) noexcept; bool compare_exchange_strong(T*&, T*, memory_order = memory_order::seq_cst) volatile noexcept; bool compare_exchange_strong(T*&, T*, memory_order = memory_order::seq_cst) noexcept;   T* fetch_add(ptrdiff_t, memory_order = memory_order::seq_cst) volatile noexcept; T* fetch_add(ptrdiff_t, memory_order = memory_order::seq_cst) noexcept; T* fetch_sub(ptrdiff_t, memory_order = memory_order::seq_cst) volatile noexcept; T* fetch_sub(ptrdiff_t, memory_order = memory_order::seq_cst) noexcept; T* fetch_max(T*, memory_order = memory_order::seq_cst) volatile noexcept; T* fetch_max(T*, memory_order = memory_order::seq_cst) noexcept; T* fetch_min(T*, memory_order = memory_order::seq_cst) volatile noexcept; T* fetch_min(T*, memory_order = memory_order::seq_cst) noexcept;   T* operator++(int) volatile noexcept; T* operator++(int) noexcept; T* operator--(int) volatile noexcept; T* operator--(int) noexcept; T* operator++() volatile noexcept; T* operator++() noexcept; T* operator--() volatile noexcept; T* operator--() noexcept; T* operator+=(ptrdiff_t) volatile noexcept; T* operator+=(ptrdiff_t) noexcept; T* operator-=(ptrdiff_t) volatile noexcept; T* operator-=(ptrdiff_t) noexcept;   void wait(T*, memory_order = memory_order::seq_cst) const volatile noexcept; void wait(T*, memory_order = memory_order::seq_cst) const noexcept; void notify_one() volatile noexcept; void notify_one() noexcept; void notify_all() volatile noexcept; void notify_all() noexcept; }; }

[edit] Class template std::atomic_ref

namespace std { template<class T> struct atomic_ref { private: T* ptr; // exposition only public: using value_type = T; static constexpr size_t required_alignment = /* implementation-defined */;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const noexcept;   explicit atomic_ref(T&); atomic_ref(const atomic_ref&) noexcept; atomic_ref& operator=(const atomic_ref&) = delete;   void store(T, memory_order = memory_order_seq_cst) const noexcept; T operator=(T) const noexcept; T load(memory_order = memory_order_seq_cst) const noexcept; operator T() const noexcept;   T exchange(T, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_weak(T&, T, memory_order, memory_order) const noexcept; bool compare_exchange_strong(T&, T, memory_order, memory_order) const noexcept; bool compare_exchange_weak(T&, T, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_strong(T&, T, memory_order = memory_order_seq_cst) const noexcept;   void wait(T, memory_order = memory_order::seq_cst) const noexcept; void notify_one() const noexcept; void notify_all() const noexcept; }; }

[edit] Specializations of std::atomic_ref for integral types

namespace std { template<> struct atomic_ref</* integral */> { private: /* integral */* ptr; // exposition only public: using value_type = /* integral */; using difference_type = value_type; static constexpr size_t required_alignment = /* implementation-defined */;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const noexcept;   explicit atomic_ref(/* integral */&); atomic_ref(const atomic_ref&) noexcept; atomic_ref& operator=(const atomic_ref&) = delete;   void store(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ operator=(/* integral */) const noexcept; /* integral */ load(memory_order = memory_order_seq_cst) const noexcept; operator /* integral */() const noexcept;   /* integral */ exchange(/* integral */, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order, memory_order) const noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order, memory_order) const noexcept; bool compare_exchange_weak(/* integral */&, /* integral */, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_strong(/* integral */&, /* integral */, memory_order = memory_order_seq_cst) const noexcept;   /* integral */ fetch_add(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_sub(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_and(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_or(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_xor(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_max(/* integral */, memory_order = memory_order_seq_cst) const noexcept; /* integral */ fetch_min(/* integral */, memory_order = memory_order_seq_cst) const noexcept;   /* integral */ operator++(int) const noexcept; /* integral */ operator--(int) const noexcept; /* integral */ operator++() const noexcept; /* integral */ operator--() const noexcept; /* integral */ operator+=(/* integral */) const noexcept; /* integral */ operator-=(/* integral */) const noexcept; /* integral */ operator&=(/* integral */) const noexcept; /* integral */ operator

[edit] Specializations of std::atomic_ref for floating-point types

namespace std { template<> struct atomic_ref</* floating-point */> { private: /* floating-point */* ptr; // exposition only public: using value_type = /* floating-point */; using difference_type = value_type; static constexpr size_t required_alignment = /* implementation-defined */;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const noexcept;   explicit atomic_ref(/* floating-point */&); atomic_ref(const atomic_ref&) noexcept; atomic_ref& operator=(const atomic_ref&) = delete;   void store(/* floating-point */, memory_order = memory_order_seq_cst) const noexcept; /* floating-point */ operator=(/* floating-point */) const noexcept; /* floating-point */ load(memory_order = memory_order_seq_cst) const noexcept; operator /* floating-point */() const noexcept;   /* floating-point */ exchange(/* floating-point */, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order, memory_order) const noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order, memory_order) const noexcept; bool compare_exchange_weak(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_strong(/* floating-point */&, /* floating-point */, memory_order = memory_order_seq_cst) const noexcept;   /* floating-point */ fetch_add(/* floating-point */, memory_order = memory_order_seq_cst) const noexcept; /* floating-point */ fetch_sub(/* floating-point */, memory_order = memory_order_seq_cst) const noexcept;   /* floating-point */ operator+=(/* floating-point */) const noexcept; /* floating-point */ operator-=(/* floating-point */) const noexcept;   void wait(/* floating-point */, memory_order = memory_order::seq_cst) const noexcept; void notify_one() const noexcept; void notify_all() const noexcept; }; }

[edit] Specializations of std::atomic_ref for pointer types

namespace std { template<class T> struct atomic_ref<T*> { private: T** ptr; // exposition only public: using value_type = T*; using difference_type = ptrdiff_t; static constexpr size_t required_alignment = /* implementation-defined */;   static constexpr bool is_always_lock_free = /* implementation-defined */; bool is_lock_free() const noexcept;   explicit atomic_ref(T*&); atomic_ref(const atomic_ref&) noexcept; atomic_ref& operator=(const atomic_ref&) = delete;   void store(T*, memory_order = memory_order_seq_cst) const noexcept; T* operator=(T*) const noexcept; T* load(memory_order = memory_order_seq_cst) const noexcept; operator T*() const noexcept;   T* exchange(T*, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_weak(T*&, T*, memory_order, memory_order) const noexcept; bool compare_exchange_strong(T*&, T*, memory_order, memory_order) const noexcept; bool compare_exchange_weak(T*&, T*, memory_order = memory_order_seq_cst) const noexcept; bool compare_exchange_strong(T*&, T*, memory_order = memory_order_seq_cst) const noexcept;   T* fetch_add(difference_type, memory_order = memory_order_seq_cst) const noexcept; T* fetch_sub(difference_type, memory_order = memory_order_seq_cst) const noexcept; T* fetch_max(T *, memory_order = memory_order::seq_cst) const noexcept; T* fetch_min(T *, memory_order = memory_order::seq_cst) const noexcept;   T* operator++(int) const noexcept; T* operator--(int) const noexcept; T* operator++() const noexcept; T* operator--() const noexcept; T* operator+=(difference_type) const noexcept; T* operator-=(difference_type) const noexcept;   void wait(T*, memory_order = memory_order::seq_cst) const noexcept; void notify_one() const noexcept; void notify_all() const noexcept; }; }

[edit] Class std::atomic_flag

namespace std { struct atomic_flag { constexpr atomic_flag() noexcept; atomic_flag(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) volatile = delete;   bool test(memory_order = memory_order::seq_cst) const volatile noexcept; bool test(memory_order = memory_order::seq_cst) const noexcept; bool test_and_set(memory_order = memory_order::seq_cst) volatile noexcept; bool test_and_set(memory_order = memory_order::seq_cst) noexcept; void clear(memory_order = memory_order::seq_cst) volatile noexcept; void clear(memory_order = memory_order::seq_cst) noexcept;   void wait(bool, memory_order = memory_order::seq_cst) const volatile noexcept; void wait(bool, memory_order = memory_order::seq_cst) const noexcept; void notify_one() volatile noexcept; void notify_one() noexcept; void notify_all() volatile noexcept; void notify_all() noexcept; }; }
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