llvm-project/libcxx/include/atomic

// -*- C++ -*-
//===--------------------------- atomic -----------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_ATOMIC
#define _LIBCPP_ATOMIC

/*
    atomic synopsis

namespace std
{

// order and consistency

typedef enum memory_order
{
    memory_order_relaxed,
    memory_order_consume,  // load-consume
    memory_order_acquire,  // load-acquire
    memory_order_release,  // store-release
    memory_order_acq_rel,  // store-release load-acquire
    memory_order_seq_cst   // store-release load-acquire
} memory_order;

template <class T> T kill_dependency(T y);

// lock-free property

#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

// flag type and operations

typedef struct atomic_flag
{
    bool test_and_set(memory_order m = memory_order_seq_cst) volatile;
    bool test_and_set(memory_order m = memory_order_seq_cst);
    void clear(memory_order m = memory_order_seq_cst) volatile;
    void clear(memory_order m = memory_order_seq_cst);
    atomic_flag() = default;
    atomic_flag(const atomic_flag&) = delete;
    atomic_flag& operator=(const atomic_flag&) = delete;
    atomic_flag& operator=(const atomic_flag&) volatile = delete;
} atomic_flag;

bool
    atomic_flag_test_and_set(volatile atomic_flag* obj);

bool
    atomic_flag_test_and_set(atomic_flag* obj);

bool
    atomic_flag_test_and_set_explicit(volatile atomic_flag* obj,
                                      memory_order m);

bool
    atomic_flag_test_and_set_explicit(atomic_flag* obj, memory_order m);

void
    atomic_flag_clear(volatile atomic_flag* obj);

void
    atomic_flag_clear(atomic_flag* obj);

void
    atomic_flag_clear_explicit(volatile atomic_flag* obj, memory_order m);

void
    atomic_flag_clear_explicit(atomic_flag* obj, memory_order m);

#define ATOMIC_FLAG_INIT see below
#define ATOMIC_VAR_INIT(value) see below

template <class T>
struct atomic
{
    bool is_lock_free() const volatile;
    bool is_lock_free() const;
    void store(T desr, memory_order m = memory_order_seq_cst) volatile;
    void store(T desr, memory_order m = memory_order_seq_cst);
    T load(memory_order m = memory_order_seq_cst) const volatile;
    T load(memory_order m = memory_order_seq_cst) const;
    operator T() const volatile;
    operator T() const;
    T exchange(T desr, memory_order m = memory_order_seq_cst) volatile;
    T exchange(T desr, memory_order m = memory_order_seq_cst);
    bool compare_exchange_weak(T& expc, T desr,
                               memory_order s, memory_order f) volatile;
    bool compare_exchange_weak(T& expc, T desr, memory_order s, memory_order f);
    bool compare_exchange_strong(T& expc, T desr,
                                 memory_order s, memory_order f) volatile;
    bool compare_exchange_strong(T& expc, T desr,
                                 memory_order s, memory_order f);
    bool compare_exchange_weak(T& expc, T desr,
                               memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_weak(T& expc, T desr,
                               memory_order m = memory_order_seq_cst);
    bool compare_exchange_strong(T& expc, T desr,
                                memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_strong(T& expc, T desr,
                                 memory_order m = memory_order_seq_cst);

    atomic() = default;
    constexpr atomic(T desr);
    atomic(const atomic&) = delete;
    atomic& operator=(const atomic&) = delete;
    atomic& operator=(const atomic&) volatile = delete;
    T operator=(T) volatile;
    T operator=(T);
};

template <>
struct atomic<integral>
{
    bool is_lock_free() const volatile;
    bool is_lock_free() const;
    void store(integral desr, memory_order m = memory_order_seq_cst) volatile;
    void store(integral desr, memory_order m = memory_order_seq_cst);
    integral load(memory_order m = memory_order_seq_cst) const volatile;
    integral load(memory_order m = memory_order_seq_cst) const;
    operator integral() const volatile;
    operator integral() const;
    integral exchange(integral desr,
                      memory_order m = memory_order_seq_cst) volatile;
    integral exchange(integral desr, memory_order m = memory_order_seq_cst);
    bool compare_exchange_weak(integral& expc, integral desr,
                               memory_order s, memory_order f) volatile;
    bool compare_exchange_weak(integral& expc, integral desr,
                               memory_order s, memory_order f);
    bool compare_exchange_strong(integral& expc, integral desr,
                                 memory_order s, memory_order f) volatile;
    bool compare_exchange_strong(integral& expc, integral desr,
                                 memory_order s, memory_order f);
    bool compare_exchange_weak(integral& expc, integral desr,
                               memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_weak(integral& expc, integral desr,
                               memory_order m = memory_order_seq_cst);
    bool compare_exchange_strong(integral& expc, integral desr,
                                memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_strong(integral& expc, integral desr,
                                 memory_order m = memory_order_seq_cst);

    integral
        fetch_add(integral op, memory_order m = memory_order_seq_cst) volatile;
    integral fetch_add(integral op, memory_order m = memory_order_seq_cst);
    integral
        fetch_sub(integral op, memory_order m = memory_order_seq_cst) volatile;
    integral fetch_sub(integral op, memory_order m = memory_order_seq_cst);
    integral
        fetch_and(integral op, memory_order m = memory_order_seq_cst) volatile;
    integral fetch_and(integral op, memory_order m = memory_order_seq_cst);
    integral
        fetch_or(integral op, memory_order m = memory_order_seq_cst) volatile;
    integral fetch_or(integral op, memory_order m = memory_order_seq_cst);
    integral
        fetch_xor(integral op, memory_order m = memory_order_seq_cst) volatile;
    integral fetch_xor(integral op, memory_order m = memory_order_seq_cst);

    atomic() = default;
    constexpr atomic(integral desr);
    atomic(const atomic&) = delete;
    atomic& operator=(const atomic&) = delete;
    atomic& operator=(const atomic&) volatile = delete;
    integral operator=(integral desr) volatile;
    integral operator=(integral desr);

    integral operator++(int) volatile;
    integral operator++(int);
    integral operator--(int) volatile;
    integral operator--(int);
    integral operator++() volatile;
    integral operator++();
    integral operator--() volatile;
    integral operator--();
    integral operator+=(integral op) volatile;
    integral operator+=(integral op);
    integral operator-=(integral op) volatile;
    integral operator-=(integral op);
    integral operator&=(integral op) volatile;
    integral operator&=(integral op);
    integral operator|=(integral op) volatile;
    integral operator|=(integral op);
    integral operator^=(integral op) volatile;
    integral operator^=(integral op);
};

template <class T>
struct atomic<T*>
{
    bool is_lock_free() const volatile;
    bool is_lock_free() const;
    void store(T* desr, memory_order m = memory_order_seq_cst) volatile;
    void store(T* desr, memory_order m = memory_order_seq_cst);
    T* load(memory_order m = memory_order_seq_cst) const volatile;
    T* load(memory_order m = memory_order_seq_cst) const;
    operator T*() const volatile;
    operator T*() const;
    T* exchange(T* desr, memory_order m = memory_order_seq_cst) volatile;
    T* exchange(T* desr, memory_order m = memory_order_seq_cst);
    bool compare_exchange_weak(T*& expc, T* desr,
                               memory_order s, memory_order f) volatile;
    bool compare_exchange_weak(T*& expc, T* desr,
                               memory_order s, memory_order f);
    bool compare_exchange_strong(T*& expc, T* desr,
                                 memory_order s, memory_order f) volatile;
    bool compare_exchange_strong(T*& expc, T* desr,
                                 memory_order s, memory_order f);
    bool compare_exchange_weak(T*& expc, T* desr,
                               memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_weak(T*& expc, T* desr,
                               memory_order m = memory_order_seq_cst);
    bool compare_exchange_strong(T*& expc, T* desr,
                                memory_order m = memory_order_seq_cst) volatile;
    bool compare_exchange_strong(T*& expc, T* desr,
                                 memory_order m = memory_order_seq_cst);
    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile;
    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst);
    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile;
    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst);

    atomic() = default;
    constexpr atomic(T* desr);
    atomic(const atomic&) = delete;
    atomic& operator=(const atomic&) = delete;
    atomic& operator=(const atomic&) volatile = delete;

    T* operator=(T*) volatile;
    T* operator=(T*);
    T* operator++(int) volatile;
    T* operator++(int);
    T* operator--(int) volatile;
    T* operator--(int);
    T* operator++() volatile;
    T* operator++();
    T* operator--() volatile;
    T* operator--();
    T* operator+=(ptrdiff_t op) volatile;
    T* operator+=(ptrdiff_t op);
    T* operator-=(ptrdiff_t op) volatile;
    T* operator-=(ptrdiff_t op);
};


template <class T>
    bool
    atomic_is_lock_free(const volatile atomic<T>* obj);

template <class T>
    bool
    atomic_is_lock_free(const atomic<T>* obj);

template <class T>
    void
    atomic_init(volatile atomic<T>* obj, T desr);

template <class T>
    void
    atomic_init(atomic<T>* obj, T desr);

template <class T>
    void
    atomic_store(volatile atomic<T>* obj, T desr);

template <class T>
    void
    atomic_store(atomic<T>* obj, T desr);

template <class T>
    void
    atomic_store_explicit(volatile atomic<T>* obj, T desr, memory_order m);

template <class T>
    void
    atomic_store_explicit(atomic<T>* obj, T desr, memory_order m);

template <class T>
    T
    atomic_load(const volatile atomic<T>* obj);

template <class T>
    T
    atomic_load(const atomic<T>* obj);

template <class T>
    T
    atomic_load_explicit(const volatile atomic<T>* obj, memory_order m);

template <class T>
    T
    atomic_load_explicit(const atomic<T>* obj, memory_order m);

template <class T>
    T
    atomic_exchange(volatile atomic<T>* obj, T desr);

template <class T>
    T
    atomic_exchange(atomic<T>* obj, T desr);

template <class T>
    T
    atomic_exchange_explicit(volatile atomic<T>* obj, T desr, memory_order m);

template <class T>
    T
    atomic_exchange_explicit(atomic<T>* obj, T desr, memory_order m);

template <class T>
    bool
    atomic_compare_exchange_weak(volatile atomic<T>* obj, T* expc, T desr);

template <class T>
    bool
    atomic_compare_exchange_weak(atomic<T>* obj, T* expc, T desr);

template <class T>
    bool
    atomic_compare_exchange_strong(volatile atomic<T>* obj, T* expc, T desr);

template <class T>
    bool
    atomic_compare_exchange_strong(atomic<T>* obj, T* expc, T desr);

template <class T>
    bool
    atomic_compare_exchange_weak_explicit(volatile atomic<T>* obj, T* expc,
                                          T desr,
                                          memory_order s, memory_order f);

template <class T>
    bool
    atomic_compare_exchange_weak_explicit(atomic<T>* obj, T* expc, T desr,
                                          memory_order s, memory_order f);

template <class T>
    bool
    atomic_compare_exchange_strong_explicit(volatile atomic<T>* obj,
                                            T* expc, T desr,
                                            memory_order s, memory_order f);

template <class T>
    bool
    atomic_compare_exchange_strong_explicit(atomic<T>* obj, T* expc,
                                            T desr,
                                            memory_order s, memory_order f);

template <class Integral>
    Integral
    atomic_fetch_add(volatile atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_add(atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_add_explicit(volatile atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_add_explicit(atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_sub(volatile atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_sub(atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_sub_explicit(volatile atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_sub_explicit(atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_and(volatile atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_and(atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_and_explicit(volatile atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_and_explicit(atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_or(volatile atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_or(atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_or_explicit(volatile atomic<Integral>* obj, Integral op,
                             memory_order m);
template <class Integral>
    Integral
    atomic_fetch_or_explicit(atomic<Integral>* obj, Integral op,
                             memory_order m);
template <class Integral>
    Integral
    atomic_fetch_xor(volatile atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_xor(atomic<Integral>* obj, Integral op);

template <class Integral>
    Integral
    atomic_fetch_xor_explicit(volatile atomic<Integral>* obj, Integral op,
                              memory_order m);
template <class Integral>
    Integral
    atomic_fetch_xor_explicit(atomic<Integral>* obj, Integral op,
                              memory_order m);

template <class T>
    T*
    atomic_fetch_add(volatile atomic<T*>* obj, ptrdiff_t op);

template <class T>
    T*
    atomic_fetch_add(atomic<T*>* obj, ptrdiff_t op);

template <class T>
    T*
    atomic_fetch_add_explicit(volatile atomic<T*>* obj, ptrdiff_t op,
                              memory_order m);
template <class T>
    T*
    atomic_fetch_add_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m);

template <class T>
    T*
    atomic_fetch_sub(volatile atomic<T*>* obj, ptrdiff_t op);

template <class T>
    T*
    atomic_fetch_sub(atomic<T*>* obj, ptrdiff_t op);

template <class T>
    T*
    atomic_fetch_sub_explicit(volatile atomic<T*>* obj, ptrdiff_t op,
                              memory_order m);
template <class T>
    T*
    atomic_fetch_sub_explicit(atomic<T*>* obj, ptrdiff_t op, memory_order m);

// Atomics for standard typedef types

typedef atomic<char>               atomic_char;
typedef atomic<signed char>        atomic_schar;
typedef atomic<unsigned char>      atomic_uchar;
typedef atomic<short>              atomic_short;
typedef atomic<unsigned short>     atomic_ushort;
typedef atomic<int>                atomic_int;
typedef atomic<unsigned int>       atomic_uint;
typedef atomic<long>               atomic_long;
typedef atomic<unsigned long>      atomic_ulong;
typedef atomic<long long>          atomic_llong;
typedef atomic<unsigned long long> atomic_ullong;
typedef atomic<char16_t>           atomic_char16_t;
typedef atomic<char32_t>           atomic_char32_t;
typedef atomic<wchar_t>            atomic_wchar_t;

typedef atomic<int_least8_t>   atomic_int_least8_t;
typedef atomic<uint_least8_t>  atomic_uint_least8_t;
typedef atomic<int_least16_t>  atomic_int_least16_t;
typedef atomic<uint_least16_t> atomic_uint_least16_t;
typedef atomic<int_least32_t>  atomic_int_least32_t;
typedef atomic<uint_least32_t> atomic_uint_least32_t;
typedef atomic<int_least64_t>  atomic_int_least64_t;
typedef atomic<uint_least64_t> atomic_uint_least64_t;

typedef atomic<int_fast8_t>   atomic_int_fast8_t;
typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
typedef atomic<int_fast16_t>  atomic_int_fast16_t;
typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
typedef atomic<int_fast32_t>  atomic_int_fast32_t;
typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
typedef atomic<int_fast64_t>  atomic_int_fast64_t;
typedef atomic<uint_fast64_t> atomic_uint_fast64_t;

typedef atomic<intptr_t>  atomic_intptr_t;
typedef atomic<uintptr_t> atomic_uintptr_t;
typedef atomic<size_t>    atomic_size_t;
typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
typedef atomic<intmax_t>  atomic_intmax_t;
typedef atomic<uintmax_t> atomic_uintmax_t;

// fences

void atomic_thread_fence(memory_order m);
void atomic_signal_fence(memory_order m);

}  // std

*/

#include <__config>
#include <cstddef>
#include <cstdint>
#include <type_traits>

#pragma GCC system_header

//// Begin Temporary Intrinsics ////

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
__atomic_is_lock_free(_Tp)
{
    return false;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_load(const volatile _Tp* __t, int)
{
    return *__t;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
__atomic_store(volatile _Tp* __t, _Tp __d, int)
{
    *__t = __d;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_exchange(volatile _Tp* __t, _Tp __d, int)
{
    _Tp __tmp = *__t;
    *__t = __d;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
__atomic_compare_exchange_strong(volatile _Tp* __o, _Tp* __e, _Tp __d, int, int)
{
    if (const_cast<_Tp&>(*__o) == *__e)
    {
        *__o = __d;
        return true;
    }
    *__e = __d;
    return false;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
__atomic_compare_exchange_weak(volatile _Tp* __o, _Tp* __e, _Tp __d, int, int)
{
    if (const_cast<_Tp&>(*__o) == *__e)
    {
        *__o = __d;
        return true;
    }
    *__e = __d;
    return false;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_fetch_add(volatile _Tp* __o, _Tp __op, int)
{
    _Tp __tmp = *__o;
    *__o += __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
__atomic_fetch_add(_Tp* volatile* __o, ptrdiff_t __op, int)
{
    _Tp* __tmp = *__o;
    *__o += __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_fetch_sub(volatile _Tp* __o, _Tp __op, int)
{
    _Tp __tmp = *__o;
    *__o -= __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
__atomic_fetch_sub(_Tp* volatile* __o, ptrdiff_t __op, int)
{
    _Tp* __tmp = *__o;
    *__o -= __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_fetch_and(volatile _Tp* __o, _Tp __op, int)
{
    _Tp __tmp = *__o;
    *__o &= __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_fetch_or(volatile _Tp* __o, _Tp __op, int)
{
    _Tp __tmp = *__o;
    *__o |= __op;
    return __tmp;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
__atomic_fetch_xor(volatile _Tp* __o, _Tp __op, int)
{
    _Tp __tmp = *__o;
    *__o ^= __op;
    return __tmp;
}

//// End Temporary Intrinsics ////

_LIBCPP_BEGIN_NAMESPACE_STD

typedef enum memory_order
{
    memory_order_relaxed, memory_order_consume, memory_order_acquire,
    memory_order_release, memory_order_acq_rel, memory_order_seq_cst
} memory_order;

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
kill_dependency(_Tp __y)
{
    return __y;
}

// general atomic<T>

template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
struct __atomic_base  // false
{
    _Tp __a_;

    _LIBCPP_INLINE_VISIBILITY
    bool is_lock_free() const volatile
        {return __atomic_is_lock_free(_Tp());}
    _LIBCPP_INLINE_VISIBILITY
    bool is_lock_free() const
        {return __atomic_is_lock_free(_Tp());}
    _LIBCPP_INLINE_VISIBILITY
    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile
        {__atomic_store(&__a_, __d, __m);}
    _LIBCPP_INLINE_VISIBILITY
    void store(_Tp __d, memory_order __m = memory_order_seq_cst)
        {__atomic_store(&__a_, __d, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp load(memory_order __m = memory_order_seq_cst) const volatile
        {return __atomic_load(&__a_, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp load(memory_order __m = memory_order_seq_cst) const
        {return __atomic_load(&__a_, __m);}
    _LIBCPP_INLINE_VISIBILITY
    operator _Tp() const volatile {return load();}
    _LIBCPP_INLINE_VISIBILITY
    operator _Tp() const          {return load();}
    _LIBCPP_INLINE_VISIBILITY
    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_exchange(&__a_, __d, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst)
        {return __atomic_exchange(&__a_, __d, __m);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_weak(_Tp& __e, _Tp __d,
                               memory_order __s, memory_order __f) volatile
        {return __atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_weak(_Tp& __e, _Tp __d,
                               memory_order __s, memory_order __f)
        {return __atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_strong(_Tp& __e, _Tp __d,
                                 memory_order __s, memory_order __f) volatile
        {return __atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_strong(_Tp& __e, _Tp __d,
                                 memory_order __s, memory_order __f)
        {return __atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_weak(_Tp& __e, _Tp __d,
                              memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_weak(_Tp& __e, _Tp __d,
                               memory_order __m = memory_order_seq_cst)
        {return __atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_strong(_Tp& __e, _Tp __d,
                              memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
    _LIBCPP_INLINE_VISIBILITY
    bool compare_exchange_strong(_Tp& __e, _Tp __d,
                                 memory_order __m = memory_order_seq_cst)
        {return __atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}

    _LIBCPP_INLINE_VISIBILITY
    __atomic_base() {} // = default;
    _LIBCPP_INLINE_VISIBILITY
    /*constexpr*/ __atomic_base(_Tp __d) : __a_(__d) {}
    __atomic_base(const __atomic_base&) = delete;
    __atomic_base& operator=(const __atomic_base&) = delete;
    __atomic_base& operator=(const __atomic_base&) volatile = delete;
};

// atomic<Integral>

template <class _Tp>
struct __atomic_base<_Tp, true>
    : public __atomic_base<_Tp, false>
{
    typedef __atomic_base<_Tp, false> __base;
    _LIBCPP_INLINE_VISIBILITY
    __atomic_base() {} // = default;
    _LIBCPP_INLINE_VISIBILITY
    /*constexpr*/ __atomic_base(_Tp __d) : __base(__d) {}

    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_fetch_add(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_add(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_fetch_sub(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_sub(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_fetch_and(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_and(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_fetch_or(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_or(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile
        {return __atomic_fetch_xor(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_xor(&this->__a_, __op, __m);}

    _LIBCPP_INLINE_VISIBILITY
    _Tp operator++(int) volatile      {return fetch_add(_Tp(1));}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator++(int)               {return fetch_add(_Tp(1));}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator--(int) volatile      {return fetch_sub(_Tp(1));}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator--(int)               {return fetch_sub(_Tp(1));}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator++() volatile         {return fetch_add(_Tp(1)) + _Tp(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator++()                  {return fetch_add(_Tp(1)) + _Tp(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator--() volatile         {return fetch_sub(_Tp(1)) - _Tp(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator--()                  {return fetch_sub(_Tp(1)) - _Tp(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator+=(_Tp __op) volatile {return fetch_add(__op) + __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator+=(_Tp __op)          {return fetch_add(__op) + __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator-=(_Tp __op) volatile {return fetch_sub(__op) - __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator-=(_Tp __op)          {return fetch_sub(__op) - __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator&=(_Tp __op) volatile {return fetch_and(__op) & __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator&=(_Tp __op)          {return fetch_and(__op) & __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator|=(_Tp __op) volatile {return fetch_or(__op) | __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator|=(_Tp __op)          {return fetch_or(__op) | __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator^=(_Tp __op) volatile {return fetch_xor(__op) ^ __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator^=(_Tp __op)          {return fetch_xor(__op) ^ __op;}
};

// atomic<T>

template <class _Tp>
struct atomic
    : public __atomic_base<_Tp>
{
    typedef __atomic_base<_Tp> __base;
    _LIBCPP_INLINE_VISIBILITY
    atomic() {} // = default;
    _LIBCPP_INLINE_VISIBILITY
    /*constexpr*/ atomic(_Tp __d) : __base(__d) {}

    _LIBCPP_INLINE_VISIBILITY
    _Tp operator=(_Tp __d) volatile
        {__base::store(__d); return __d;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp operator=(_Tp __d)
        {__base::store(__d); return __d;}
};

// atomic<T*>

template <class _Tp>
struct atomic<_Tp*>
    : public __atomic_base<_Tp*>
{
    typedef __atomic_base<_Tp*> __base;
    _LIBCPP_INLINE_VISIBILITY
    atomic() {} // = default;
    _LIBCPP_INLINE_VISIBILITY
    /*constexpr*/ atomic(_Tp* __d) : __base(__d) {}

    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator=(_Tp* __d) volatile
        {__base::store(__d); return __d;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator=(_Tp* __d)
        {__base::store(__d); return __d;}

    _LIBCPP_INLINE_VISIBILITY
    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
                                                                        volatile
        {return __atomic_fetch_add(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_add(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
                                                                        volatile
        {return __atomic_fetch_sub(&this->__a_, __op, __m);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst)
        {return __atomic_fetch_sub(&this->__a_, __op, __m);}

    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator++(int) volatile            {return fetch_add(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator++(int)                     {return fetch_add(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator--(int) volatile            {return fetch_sub(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator--(int)                     {return fetch_sub(1);}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator++() volatile               {return fetch_add(1) + 1;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator++()                        {return fetch_add(1) + 1;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator--() volatile               {return fetch_sub(1) - 1;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator--()                        {return fetch_sub(1) - 1;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator+=(ptrdiff_t __op) volatile {return fetch_add(__op) + __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator+=(ptrdiff_t __op)          {return fetch_add(__op) + __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator-=(ptrdiff_t __op) volatile {return fetch_sub(__op) - __op;}
    _LIBCPP_INLINE_VISIBILITY
    _Tp* operator-=(ptrdiff_t __op)          {return fetch_sub(__op) - __op;}
};

// atomic_is_lock_free

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_is_lock_free(const volatile atomic<_Tp>* __o)
{
    return __o->is_lock_free();
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_is_lock_free(const atomic<_Tp>* __o)
{
    return __o->is_lock_free();
}

// atomic_init

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_init(volatile atomic<_Tp>* __o, _Tp __d)
{
    __o->__a_ = __d;
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_init(atomic<_Tp>* __o, _Tp __d)
{
    __o->__a_ = __d;
}

// atomic_store

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_store(volatile atomic<_Tp>* __o, _Tp __d)
{
    __o->store(__d);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_store(atomic<_Tp>* __o, _Tp __d)
{
    __o->store(__d);
}

// atomic_store_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_store_explicit(volatile atomic<_Tp>* __o, _Tp __d, memory_order __m)
{
    __o->store(__d, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
atomic_store_explicit(atomic<_Tp>* __o, _Tp __d, memory_order __m)
{
    __o->store(__d, __m);
}

// atomic_load

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_load(const volatile atomic<_Tp>* __o)
{
    return __o->load();
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_load(const atomic<_Tp>* __o)
{
    return __o->load();
}

// atomic_load_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m)
{
    return __o->load(__m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m)
{
    return __o->load(__m);
}

// atomic_exchange

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_exchange(volatile atomic<_Tp>* __o, _Tp __d)
{
    return __o->exchange(__d);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_exchange(atomic<_Tp>* __o, _Tp __d)
{
    return __o->exchange(__d);
}

// atomic_exchange_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_exchange_explicit(volatile atomic<_Tp>* __o, _Tp __d, memory_order __m)
{
    return __o->exchange(__d, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
atomic_exchange_explicit(atomic<_Tp>* __o, _Tp __d, memory_order __m)
{
    return __o->exchange(__d, __m);
}

// atomic_compare_exchange_weak

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, _Tp* __e, _Tp __d)
{
    return __o->compare_exchange_weak(*__e, __d);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_weak(atomic<_Tp>* __o, _Tp* __e, _Tp __d)
{
    return __o->compare_exchange_weak(*__e, __d);
}

// atomic_compare_exchange_strong

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, _Tp* __e, _Tp __d)
{
    return __o->compare_exchange_strong(*__e, __d);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_strong(atomic<_Tp>* __o, _Tp* __e, _Tp __d)
{
    return __o->compare_exchange_strong(*__e, __d);
}

// atomic_compare_exchange_weak_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, _Tp* __e,
                                      _Tp __d,
                                      memory_order __s, memory_order __f)
{
    return __o->compare_exchange_weak(*__e, __d, __s, __f);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, _Tp* __e, _Tp __d,
                                      memory_order __s, memory_order __f)
{
    return __o->compare_exchange_weak(*__e, __d, __s, __f);
}

// atomic_compare_exchange_strong_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
                                        _Tp* __e, _Tp __d,
                                        memory_order __s, memory_order __f)
{
    return __o->compare_exchange_strong(*__e, __d, __s, __f);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, _Tp* __e,
                                        _Tp __d,
                                        memory_order __s, memory_order __f)
{
    return __o->compare_exchange_strong(*__e, __d, __s, __f);
}

// atomic_fetch_add

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_add(volatile atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_add(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_add(atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_add(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_add(volatile atomic<_Tp*>* __o, ptrdiff_t __op)
{
    return __o->fetch_add(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_add(atomic<_Tp*>* __o, ptrdiff_t __op)
{
    return __o->fetch_add(__op);
}

// atomic_fetch_add_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_add(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_add_explicit(atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_add(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_add_explicit(volatile atomic<_Tp*>* __o, ptrdiff_t __op,
                          memory_order __m)
{
    return __o->fetch_add(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_add_explicit(atomic<_Tp*>* __o, ptrdiff_t __op, memory_order __m)
{
    return __o->fetch_add(__op, __m);
}

// atomic_fetch_sub

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_sub(volatile atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_sub(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_sub(atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_sub(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_sub(volatile atomic<_Tp*>* __o, ptrdiff_t __op)
{
    return __o->fetch_sub(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_sub(atomic<_Tp*>* __o, ptrdiff_t __op)
{
    return __o->fetch_sub(__op);
}

// atomic_fetch_sub_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_sub(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_sub_explicit(atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_sub(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_sub_explicit(volatile atomic<_Tp*>* __o, ptrdiff_t __op,
                          memory_order __m)
{
    return __o->fetch_sub(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp*
atomic_fetch_sub_explicit(atomic<_Tp*>* __o, ptrdiff_t __op, memory_order __m)
{
    return __o->fetch_sub(__op, __m);
}

// atomic_fetch_and

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_and(volatile atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_and(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_and(atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_and(__op);
}

// atomic_fetch_and_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_and(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_and_explicit(atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_and(__op, __m);
}

// atomic_fetch_or

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_or(volatile atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_or(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_or(atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_or(__op);
}

// atomic_fetch_or_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_or(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_or_explicit(atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_or(__op, __m);
}

// atomic_fetch_xor

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_xor(volatile atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_xor(__op);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_xor(atomic<_Tp>* __o, _Tp __op)
{
    return __o->fetch_xor(__op);
}

// atomic_fetch_xor_explicit

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_xor(__op, __m);
}

template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
typename enable_if
<
    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
    _Tp
>::type
atomic_fetch_xor_explicit(atomic<_Tp>* __o, _Tp __op, memory_order __m)
{
    return __o->fetch_xor(__op, __m);
}

// Atomics for standard typedef types

typedef atomic<char>               atomic_char;
typedef atomic<signed char>        atomic_schar;
typedef atomic<unsigned char>      atomic_uchar;
typedef atomic<short>              atomic_short;
typedef atomic<unsigned short>     atomic_ushort;
typedef atomic<int>                atomic_int;
typedef atomic<unsigned int>       atomic_uint;
typedef atomic<long>               atomic_long;
typedef atomic<unsigned long>      atomic_ulong;
typedef atomic<long long>          atomic_llong;
typedef atomic<unsigned long long> atomic_ullong;
typedef atomic<char16_t>           atomic_char16_t;
typedef atomic<char32_t>           atomic_char32_t;
typedef atomic<wchar_t>            atomic_wchar_t;

typedef atomic<int_least8_t>   atomic_int_least8_t;
typedef atomic<uint_least8_t>  atomic_uint_least8_t;
typedef atomic<int_least16_t>  atomic_int_least16_t;
typedef atomic<uint_least16_t> atomic_uint_least16_t;
typedef atomic<int_least32_t>  atomic_int_least32_t;
typedef atomic<uint_least32_t> atomic_uint_least32_t;
typedef atomic<int_least64_t>  atomic_int_least64_t;
typedef atomic<uint_least64_t> atomic_uint_least64_t;

typedef atomic<int_fast8_t>   atomic_int_fast8_t;
typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
typedef atomic<int_fast16_t>  atomic_int_fast16_t;
typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
typedef atomic<int_fast32_t>  atomic_int_fast32_t;
typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
typedef atomic<int_fast64_t>  atomic_int_fast64_t;
typedef atomic<uint_fast64_t> atomic_uint_fast64_t;

typedef atomic<intptr_t>  atomic_intptr_t;
typedef atomic<uintptr_t> atomic_uintptr_t;
typedef atomic<size_t>    atomic_size_t;
typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
typedef atomic<intmax_t>  atomic_intmax_t;
typedef atomic<uintmax_t> atomic_uintmax_t;

/*
// flag type and operations

typedef bool __atomic_flag__;

struct atomic_flag;

bool atomic_flag_test_and_set(volatile atomic_flag*);
bool atomic_flag_test_and_set(atomic_flag*);
bool atomic_flag_test_and_set_explicit(volatile atomic_flag*, memory_order);
bool atomic_flag_test_and_set_explicit(atomic_flag*, memory_order);
void atomic_flag_clear(volatile atomic_flag*);
void atomic_flag_clear(atomic_flag*);
void atomic_flag_clear_explicit(volatile atomic_flag*, memory_order);
void atomic_flag_clear_explicit(atomic_flag*, memory_order);

typedef struct _LIBCPP_VISIBLE atomic_flag
{
    __atomic_flag__ __flg_;

    _LIBCPP_INLINE_VISIBILITY
    bool test_and_set(memory_order __o = memory_order_seq_cst) volatile
        {return atomic_flag_test_and_set_explicit(this, __o);}
    _LIBCPP_INLINE_VISIBILITY
    bool test_and_set(memory_order __o = memory_order_seq_cst)
        {return atomic_flag_test_and_set_explicit(this, __o);}

    _LIBCPP_INLINE_VISIBILITY
    void clear(memory_order __o = memory_order_seq_cst) volatile
        {atomic_flag_clear_explicit(this, __o);}
    _LIBCPP_INLINE_VISIBILITY
    void clear(memory_order __o = memory_order_seq_cst)
        {atomic_flag_clear_explicit(this, __o);}

#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
    atomic_flag() = default;
#else
    _LIBCPP_INLINE_VISIBILITY
    atomic_flag() {};
#endif

#ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
    atomic_flag(const atomic_flag&) = delete;
    atomic_flag& operator=(const atomic_flag&) = delete;
    atomic_flag& operator=(const atomic_flag&) volatile = delete;
#else
private:
    atomic_flag(const atomic_flag&);
    atomic_flag& operator=(const atomic_flag&);
    atomic_flag& operator=(const atomic_flag&) volatile;
public:
#endif
} atomic_flag;

inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_flag_test_and_set(volatile atomic_flag* __f)
{
    return __atomic_exchange(&__f->__flg_, __atomic_flag__(true),
                             memory_order_seq_cst)
            == __atomic_flag__(true);
}

inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_flag_test_and_set(atomic_flag* __f)
{
    return atomic_flag_test_and_set(const_cast<volatile atomic_flag*>(__f));
}

inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_flag_test_and_set_explicit(volatile atomic_flag* __f, memory_order __o)
{
    return __atomic_exchange(&__f->__flg_, __atomic_flag__(true), __o)
            == __atomic_flag__(true);
}

inline _LIBCPP_INLINE_VISIBILITY
bool
atomic_flag_test_and_set_explicit(atomic_flag* __f, memory_order __o)
{
    return atomic_flag_test_and_set_explicit(const_cast<volatile atomic_flag*>
                                                                    (__f), __o);
}

inline _LIBCPP_INLINE_VISIBILITY
void
atomic_flag_clear(volatile atomic_flag* __f)
{
    __atomic_store(&__f->__flg_, __atomic_flag__(false), memory_order_seq_cst);
}

inline _LIBCPP_INLINE_VISIBILITY
void
atomic_flag_clear(atomic_flag* __f)
{
    atomic_flag_clear(const_cast<volatile atomic_flag*>(__f));
}

inline _LIBCPP_INLINE_VISIBILITY
void
atomic_flag_clear_explicit(volatile atomic_flag* __f, memory_order __o)
{
    __atomic_store(&__f->__flg_, __atomic_flag__(false), __o);
}

inline _LIBCPP_INLINE_VISIBILITY
void
atomic_flag_clear_explicit(atomic_flag* __f, memory_order __o)
{
    atomic_flag_clear_explicit(const_cast<volatile atomic_flag*>(__f), __o);
}

#define ATOMIC_FLAG_INIT {false}
#define ATOMIC_VAR_INIT(__v) {__v}

inline _LIBCPP_INLINE_VISIBILITY
memory_order
__translate_memory_order(memory_order __o)
{
    switch (__o)
    {
    case memory_order_acq_rel:
        return memory_order_acquire;
    case memory_order_release:
        return memory_order_relaxed;
    }
    return __o;
}

*/
_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_ATOMIC