namespace std {
enum memory_order;
template <class T>
T kill_dependency(T y) noexcept;
#define ATOMIC_BOOL_LOCK_FREE unspecified
#define ATOMIC_CHAR_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
template<class T> struct atomic;
template<class T> struct atomic<T*>;
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_init(volatile atomic<T>*, typename atomic<T>::value_type) noexcept;
template<class T>
void atomic_init(atomic<T>*, typename atomic<T>::value_type) 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>*, T) 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;
#define ATOMIC_VAR_INIT(value) see below
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_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>;
struct atomic_flag;
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;
#define ATOMIC_FLAG_INIT see below
extern "C" void atomic_thread_fence(memory_order) noexcept;
extern "C" void atomic_signal_fence(memory_order) noexcept;
}