// -*- C++ -*- header. // Copyright (C) 2008-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /** @file bits/atomic_base.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{atomic} */ #ifndef _GLIBCXX_ATOMIC_BASE_H #define _GLIBCXX_ATOMIC_BASE_H 1 #pragma GCC system_header #include <bits/c++config.h> #include <stdint.h> #include <bits/atomic_lockfree_defines.h> #include <bits/move.h> #ifndef _GLIBCXX_ALWAYS_INLINE #define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__)) #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @defgroup atomics Atomics * * Components for performing atomic operations. * @{ */ /// Enumeration for memory_order #if __cplusplus > 201703L enum class memory_order : int { relaxed, consume, acquire, release, acq_rel, seq_cst }; 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; #else 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; #endif enum __memory_order_modifier { __memory_order_mask = 0x0ffff, __memory_order_modifier_mask = 0xffff0000, __memory_order_hle_acquire = 0x10000, __memory_order_hle_release = 0x20000 }; constexpr memory_order operator|(memory_order __m, __memory_order_modifier __mod) { return memory_order(int(__m) | int(__mod)); } constexpr memory_order operator&(memory_order __m, __memory_order_modifier __mod) { return memory_order(int(__m) & int(__mod)); } // Drop release ordering as per [atomics.types.operations.req]/21 constexpr memory_order __cmpexch_failure_order2(memory_order __m) noexcept { return __m == memory_order_acq_rel ? memory_order_acquire : __m == memory_order_release ? memory_order_relaxed : __m; } constexpr memory_order __cmpexch_failure_order(memory_order __m) noexcept { return memory_order(__cmpexch_failure_order2(__m & __memory_order_mask) | __memory_order_modifier(__m & __memory_order_modifier_mask)); } _GLIBCXX_ALWAYS_INLINE void atomic_thread_fence(memory_order __m) noexcept { __atomic_thread_fence(int(__m)); } _GLIBCXX_ALWAYS_INLINE void atomic_signal_fence(memory_order __m) noexcept { __atomic_signal_fence(int(__m)); } /// kill_dependency template<typename _Tp> inline _Tp kill_dependency(_Tp __y) noexcept { _Tp __ret(__y); return __ret; } // Base types for atomics. template<typename _IntTp> struct __atomic_base; #if __cplusplus <= 201703L # define _GLIBCXX20_INIT(I) #else # define __cpp_lib_atomic_value_initialization 201911L # define _GLIBCXX20_INIT(I) = I #endif #define ATOMIC_VAR_INIT(_VI) { _VI } template<typename _Tp> struct atomic; template<typename _Tp> struct atomic<_Tp*>; /* The target's "set" value for test-and-set may not be exactly 1. */ #if __GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1 typedef bool __atomic_flag_data_type; #else typedef unsigned char __atomic_flag_data_type; #endif /** * @brief Base type for atomic_flag. * * Base type is POD with data, allowing atomic_flag to derive from * it and meet the standard layout type requirement. In addition to * compatibility with a C interface, this allows different * implementations of atomic_flag to use the same atomic operation * functions, via a standard conversion to the __atomic_flag_base * argument. */ _GLIBCXX_BEGIN_EXTERN_C struct __atomic_flag_base { __atomic_flag_data_type _M_i _GLIBCXX20_INIT({}); }; _GLIBCXX_END_EXTERN_C #define ATOMIC_FLAG_INIT { 0 } /// atomic_flag struct atomic_flag : public __atomic_flag_base { atomic_flag() noexcept = default; ~atomic_flag() noexcept = default; atomic_flag(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) volatile = delete; // Conversion to ATOMIC_FLAG_INIT. constexpr atomic_flag(bool __i) noexcept : __atomic_flag_base{ _S_init(__i) } { } _GLIBCXX_ALWAYS_INLINE bool test_and_set(memory_order __m = memory_order_seq_cst) noexcept { return __atomic_test_and_set (&_M_i, int(__m)); } _GLIBCXX_ALWAYS_INLINE bool test_and_set(memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_test_and_set (&_M_i, int(__m)); } _GLIBCXX_ALWAYS_INLINE void clear(memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_consume); __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __atomic_clear (&_M_i, int(__m)); } _GLIBCXX_ALWAYS_INLINE void clear(memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_consume); __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __atomic_clear (&_M_i, int(__m)); } private: static constexpr __atomic_flag_data_type _S_init(bool __i) { return __i ? __GCC_ATOMIC_TEST_AND_SET_TRUEVAL : 0; } }; /// Base class for atomic integrals. // // For each of the integral types, define atomic_[integral type] struct // // atomic_bool bool // atomic_char char // atomic_schar signed char // atomic_uchar unsigned char // atomic_short short // atomic_ushort unsigned short // atomic_int int // atomic_uint unsigned int // atomic_long long // atomic_ulong unsigned long // atomic_llong long long // atomic_ullong unsigned long long // atomic_char8_t char8_t // atomic_char16_t char16_t // atomic_char32_t char32_t // atomic_wchar_t wchar_t // // NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or // 8 bytes, since that is what GCC built-in functions for atomic // memory access expect. template<typename _ITp> struct __atomic_base { using value_type = _ITp; using difference_type = value_type; private: typedef _ITp __int_type; static constexpr int _S_alignment = sizeof(_ITp) > alignof(_ITp) ? sizeof(_ITp) : alignof(_ITp); alignas(_S_alignment) __int_type _M_i _GLIBCXX20_INIT(0); public: __atomic_base() noexcept = default; ~__atomic_base() noexcept = default; __atomic_base(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) volatile = delete; // Requires __int_type convertible to _M_i. constexpr __atomic_base(__int_type __i) noexcept : _M_i (__i) { } operator __int_type() const noexcept { return load(); } operator __int_type() const volatile noexcept { return load(); } __int_type operator=(__int_type __i) noexcept { store(__i); return __i; } __int_type operator=(__int_type __i) volatile noexcept { store(__i); return __i; } __int_type operator++(int) noexcept { return fetch_add(1); } __int_type operator++(int) volatile noexcept { return fetch_add(1); } __int_type operator--(int) noexcept { return fetch_sub(1); } __int_type operator--(int) volatile noexcept { return fetch_sub(1); } __int_type operator++() noexcept { return __atomic_add_fetch(&_M_i, 1, int(memory_order_seq_cst)); } __int_type operator++() volatile noexcept { return __atomic_add_fetch(&_M_i, 1, int(memory_order_seq_cst)); } __int_type operator--() noexcept { return __atomic_sub_fetch(&_M_i, 1, int(memory_order_seq_cst)); } __int_type operator--() volatile noexcept { return __atomic_sub_fetch(&_M_i, 1, int(memory_order_seq_cst)); } __int_type operator+=(__int_type __i) noexcept { return __atomic_add_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator+=(__int_type __i) volatile noexcept { return __atomic_add_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator-=(__int_type __i) noexcept { return __atomic_sub_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator-=(__int_type __i) volatile noexcept { return __atomic_sub_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator&=(__int_type __i) noexcept { return __atomic_and_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator&=(__int_type __i) volatile noexcept { return __atomic_and_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator|=(__int_type __i) noexcept { return __atomic_or_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator|=(__int_type __i) volatile noexcept { return __atomic_or_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator^=(__int_type __i) noexcept { return __atomic_xor_fetch(&_M_i, __i, int(memory_order_seq_cst)); } __int_type operator^=(__int_type __i) volatile noexcept { return __atomic_xor_fetch(&_M_i, __i, int(memory_order_seq_cst)); } bool is_lock_free() const noexcept { // Use a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_i), reinterpret_cast<void *>(-_S_alignment)); } bool is_lock_free() const volatile noexcept { // Use a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_i), reinterpret_cast<void *>(-_S_alignment)); } _GLIBCXX_ALWAYS_INLINE void store(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE void store(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type load(memory_order __m = memory_order_seq_cst) const noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type load(memory_order __m = memory_order_seq_cst) const volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type exchange(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_exchange_n(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type exchange(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_exchange_n(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) noexcept { return compare_exchange_weak(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) volatile noexcept { return compare_exchange_weak(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) noexcept { return compare_exchange_strong(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) volatile noexcept { return compare_exchange_strong(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_add(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_add(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_add(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_add(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_sub(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_sub(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_sub(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_sub(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_and(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_and(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_and(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_and(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_or(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_or(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_or(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_or(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_xor(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_xor(&_M_i, __i, int(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_xor(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_xor(&_M_i, __i, int(__m)); } }; /// Partial specialization for pointer types. template<typename _PTp> struct __atomic_base<_PTp*> { private: typedef _PTp* __pointer_type; __pointer_type _M_p _GLIBCXX20_INIT(nullptr); // Factored out to facilitate explicit specialization. constexpr ptrdiff_t _M_type_size(ptrdiff_t __d) const { return __d * sizeof(_PTp); } constexpr ptrdiff_t _M_type_size(ptrdiff_t __d) const volatile { return __d * sizeof(_PTp); } public: __atomic_base() noexcept = default; ~__atomic_base() noexcept = default; __atomic_base(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) volatile = delete; // Requires __pointer_type convertible to _M_p. constexpr __atomic_base(__pointer_type __p) noexcept : _M_p (__p) { } operator __pointer_type() const noexcept { return load(); } operator __pointer_type() const volatile noexcept { return load(); } __pointer_type operator=(__pointer_type __p) noexcept { store(__p); return __p; } __pointer_type operator=(__pointer_type __p) volatile noexcept { store(__p); return __p; } __pointer_type operator++(int) noexcept { return fetch_add(1); } __pointer_type operator++(int) volatile noexcept { return fetch_add(1); } __pointer_type operator--(int) noexcept { return fetch_sub(1); } __pointer_type operator--(int) volatile noexcept { return fetch_sub(1); } __pointer_type operator++() noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(1), int(memory_order_seq_cst)); } __pointer_type operator++() volatile noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(1), int(memory_order_seq_cst)); } __pointer_type operator--() noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(1), int(memory_order_seq_cst)); } __pointer_type operator--() volatile noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(1), int(memory_order_seq_cst)); } __pointer_type operator+=(ptrdiff_t __d) noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(__d), int(memory_order_seq_cst)); } __pointer_type operator+=(ptrdiff_t __d) volatile noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(__d), int(memory_order_seq_cst)); } __pointer_type operator-=(ptrdiff_t __d) noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(__d), int(memory_order_seq_cst)); } __pointer_type operator-=(ptrdiff_t __d) volatile noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(__d), int(memory_order_seq_cst)); } bool is_lock_free() const noexcept { // Produce a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_p), reinterpret_cast<void *>(-__alignof(_M_p))); } bool is_lock_free() const volatile noexcept { // Produce a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_p), reinterpret_cast<void *>(-__alignof(_M_p))); } _GLIBCXX_ALWAYS_INLINE void store(__pointer_type __p, memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_p, __p, int(__m)); } _GLIBCXX_ALWAYS_INLINE void store(__pointer_type __p, memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_p, __p, int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type load(memory_order __m = memory_order_seq_cst) const noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_p, int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type load(memory_order __m = memory_order_seq_cst) const volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_p, int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type exchange(__pointer_type __p, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_exchange_n(&_M_p, __p, int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type exchange(__pointer_type __p, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_exchange_n(&_M_p, __p, int(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, int(__m1), int(__m2)); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_add(&_M_p, _M_type_size(__d), int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_add(&_M_p, _M_type_size(__d), int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), int(__m)); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), int(__m)); } }; #if __cplusplus > 201703L // Implementation details of atomic_ref and atomic<floating-point>. namespace __atomic_impl { // Remove volatile and create a non-deduced context for value arguments. template<typename _Tp> using _Val = remove_volatile_t<_Tp>; // As above, but for difference_type arguments. template<typename _Tp> using _Diff = conditional_t<is_pointer_v<_Tp>, ptrdiff_t, _Val<_Tp>>; template<size_t _Size, size_t _Align> _GLIBCXX_ALWAYS_INLINE bool is_lock_free() noexcept { // Produce a fake, minimally aligned pointer. return __atomic_is_lock_free(_Size, reinterpret_cast<void *>(-_Align)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE void store(_Tp* __ptr, _Val<_Tp> __t, memory_order __m) noexcept { __atomic_store(__ptr, std::__addressof(__t), int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Val<_Tp> load(const _Tp* __ptr, memory_order __m) noexcept { alignas(_Tp) unsigned char __buf[sizeof(_Tp)]; auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf); __atomic_load(__ptr, __dest, int(__m)); return *__dest; } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Val<_Tp> exchange(_Tp* __ptr, _Val<_Tp> __desired, memory_order __m) noexcept { alignas(_Tp) unsigned char __buf[sizeof(_Tp)]; auto* __dest = reinterpret_cast<_Val<_Tp>*>(__buf); __atomic_exchange(__ptr, std::__addressof(__desired), __dest, int(__m)); return *__dest; } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(_Tp* __ptr, _Val<_Tp>& __expected, _Val<_Tp> __desired, memory_order __success, memory_order __failure) noexcept { return __atomic_compare_exchange(__ptr, std::__addressof(__expected), std::__addressof(__desired), true, int(__success), int(__failure)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(_Tp* __ptr, _Val<_Tp>& __expected, _Val<_Tp> __desired, memory_order __success, memory_order __failure) noexcept { return __atomic_compare_exchange(__ptr, std::__addressof(__expected), std::__addressof(__desired), false, int(__success), int(__failure)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp fetch_add(_Tp* __ptr, _Diff<_Tp> __i, memory_order __m) noexcept { return __atomic_fetch_add(__ptr, __i, int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp fetch_sub(_Tp* __ptr, _Diff<_Tp> __i, memory_order __m) noexcept { return __atomic_fetch_sub(__ptr, __i, int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp fetch_and(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept { return __atomic_fetch_and(__ptr, __i, int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp fetch_or(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept { return __atomic_fetch_or(__ptr, __i, int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp fetch_xor(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept { return __atomic_fetch_xor(__ptr, __i, int(__m)); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp __add_fetch(_Tp* __ptr, _Diff<_Tp> __i) noexcept { return __atomic_add_fetch(__ptr, __i, __ATOMIC_SEQ_CST); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp __sub_fetch(_Tp* __ptr, _Diff<_Tp> __i) noexcept { return __atomic_sub_fetch(__ptr, __i, __ATOMIC_SEQ_CST); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp __and_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept { return __atomic_and_fetch(__ptr, __i, __ATOMIC_SEQ_CST); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp __or_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept { return __atomic_or_fetch(__ptr, __i, __ATOMIC_SEQ_CST); } template<typename _Tp> _GLIBCXX_ALWAYS_INLINE _Tp __xor_fetch(_Tp* __ptr, _Val<_Tp> __i) noexcept { return __atomic_xor_fetch(__ptr, __i, __ATOMIC_SEQ_CST); } template<typename _Tp> _Tp __fetch_add_flt(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept { _Val<_Tp> __oldval = load(__ptr, memory_order_relaxed); _Val<_Tp> __newval = __oldval + __i; while (!compare_exchange_weak(__ptr, __oldval, __newval, __m, memory_order_relaxed)) __newval = __oldval + __i; return __oldval; } template<typename _Tp> _Tp __fetch_sub_flt(_Tp* __ptr, _Val<_Tp> __i, memory_order __m) noexcept { _Val<_Tp> __oldval = load(__ptr, memory_order_relaxed); _Val<_Tp> __newval = __oldval - __i; while (!compare_exchange_weak(__ptr, __oldval, __newval, __m, memory_order_relaxed)) __newval = __oldval - __i; return __oldval; } template<typename _Tp> _Tp __add_fetch_flt(_Tp* __ptr, _Val<_Tp> __i) noexcept { _Val<_Tp> __oldval = load(__ptr, memory_order_relaxed); _Val<_Tp> __newval = __oldval + __i; while (!compare_exchange_weak(__ptr, __oldval, __newval, memory_order_seq_cst, memory_order_relaxed)) __newval = __oldval + __i; return __newval; } template<typename _Tp> _Tp __sub_fetch_flt(_Tp* __ptr, _Val<_Tp> __i) noexcept { _Val<_Tp> __oldval = load(__ptr, memory_order_relaxed); _Val<_Tp> __newval = __oldval - __i; while (!compare_exchange_weak(__ptr, __oldval, __newval, memory_order_seq_cst, memory_order_relaxed)) __newval = __oldval - __i; return __newval; } } // namespace __atomic_impl // base class for atomic<floating-point-type> template<typename _Fp> struct __atomic_float { static_assert(is_floating_point_v<_Fp>); static constexpr size_t _S_alignment = __alignof__(_Fp); public: using value_type = _Fp; using difference_type = value_type; static constexpr bool is_always_lock_free = __atomic_always_lock_free(sizeof(_Fp), 0); __atomic_float() = default; constexpr __atomic_float(_Fp __t) : _M_fp(__t) { } __atomic_float(const __atomic_float&) = delete; __atomic_float& operator=(const __atomic_float&) = delete; __atomic_float& operator=(const __atomic_float&) volatile = delete; _Fp operator=(_Fp __t) volatile noexcept { this->store(__t); return __t; } _Fp operator=(_Fp __t) noexcept { this->store(__t); return __t; } bool is_lock_free() const volatile noexcept { return __atomic_impl::is_lock_free<sizeof(_Fp), _S_alignment>(); } bool is_lock_free() const noexcept { return __atomic_impl::is_lock_free<sizeof(_Fp), _S_alignment>(); } void store(_Fp __t, memory_order __m = memory_order_seq_cst) volatile noexcept { __atomic_impl::store(&_M_fp, __t, __m); } void store(_Fp __t, memory_order __m = memory_order_seq_cst) noexcept { __atomic_impl::store(&_M_fp, __t, __m); } _Fp load(memory_order __m = memory_order_seq_cst) const volatile noexcept { return __atomic_impl::load(&_M_fp, __m); } _Fp load(memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::load(&_M_fp, __m); } operator _Fp() const volatile noexcept { return this->load(); } operator _Fp() const noexcept { return this->load(); } _Fp exchange(_Fp __desired, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_impl::exchange(&_M_fp, __desired, __m); } _Fp exchange(_Fp __desired, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_impl::exchange(&_M_fp, __desired, __m); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) noexcept { return __atomic_impl::compare_exchange_weak(&_M_fp, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) volatile noexcept { return __atomic_impl::compare_exchange_weak(&_M_fp, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) noexcept { return __atomic_impl::compare_exchange_strong(&_M_fp, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) volatile noexcept { return __atomic_impl::compare_exchange_strong(&_M_fp, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) volatile noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) volatile noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } value_type fetch_add(value_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_impl::__fetch_add_flt(&_M_fp, __i, __m); } value_type fetch_add(value_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_impl::__fetch_add_flt(&_M_fp, __i, __m); } value_type fetch_sub(value_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_impl::__fetch_sub_flt(&_M_fp, __i, __m); } value_type fetch_sub(value_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_impl::__fetch_sub_flt(&_M_fp, __i, __m); } value_type operator+=(value_type __i) noexcept { return __atomic_impl::__add_fetch_flt(&_M_fp, __i); } value_type operator+=(value_type __i) volatile noexcept { return __atomic_impl::__add_fetch_flt(&_M_fp, __i); } value_type operator-=(value_type __i) noexcept { return __atomic_impl::__sub_fetch_flt(&_M_fp, __i); } value_type operator-=(value_type __i) volatile noexcept { return __atomic_impl::__sub_fetch_flt(&_M_fp, __i); } private: alignas(_S_alignment) _Fp _M_fp _GLIBCXX20_INIT(0); }; #undef _GLIBCXX20_INIT template<typename _Tp, bool = is_integral_v<_Tp>, bool = is_floating_point_v<_Tp>> struct __atomic_ref; // base class for non-integral, non-floating-point, non-pointer types template<typename _Tp> struct __atomic_ref<_Tp, false, false> { static_assert(is_trivially_copyable_v<_Tp>); // 1/2/4/8/16-byte types must be aligned to at least their size. static constexpr int _S_min_alignment = (sizeof(_Tp) & (sizeof(_Tp) - 1)) || sizeof(_Tp) > 16 ? 0 : sizeof(_Tp); public: using value_type = _Tp; static constexpr bool is_always_lock_free = __atomic_always_lock_free(sizeof(_Tp), 0); static constexpr size_t required_alignment = _S_min_alignment > alignof(_Tp) ? _S_min_alignment : alignof(_Tp); __atomic_ref& operator=(const __atomic_ref&) = delete; explicit __atomic_ref(_Tp& __t) : _M_ptr(std::__addressof(__t)) { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); } __atomic_ref(const __atomic_ref&) noexcept = default; _Tp operator=(_Tp __t) const noexcept { this->store(__t); return __t; } operator _Tp() const noexcept { return this->load(); } bool is_lock_free() const noexcept { return __atomic_impl::is_lock_free<sizeof(_Tp), required_alignment>(); } void store(_Tp __t, memory_order __m = memory_order_seq_cst) const noexcept { __atomic_impl::store(_M_ptr, __t, __m); } _Tp load(memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::load(_M_ptr, __m); } _Tp exchange(_Tp __desired, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::exchange(_M_ptr, __desired, __m); } bool compare_exchange_weak(_Tp& __expected, _Tp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_weak(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Tp& __expected, _Tp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_strong(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Tp& __expected, _Tp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Tp& __expected, _Tp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } private: _Tp* _M_ptr; }; // base class for atomic_ref<integral-type> template<typename _Tp> struct __atomic_ref<_Tp, true, false> { static_assert(is_integral_v<_Tp>); public: using value_type = _Tp; using difference_type = value_type; static constexpr bool is_always_lock_free = __atomic_always_lock_free(sizeof(_Tp), 0); static constexpr size_t required_alignment = sizeof(_Tp) > alignof(_Tp) ? sizeof(_Tp) : alignof(_Tp); __atomic_ref() = delete; __atomic_ref& operator=(const __atomic_ref&) = delete; explicit __atomic_ref(_Tp& __t) : _M_ptr(&__t) { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); } __atomic_ref(const __atomic_ref&) noexcept = default; _Tp operator=(_Tp __t) const noexcept { this->store(__t); return __t; } operator _Tp() const noexcept { return this->load(); } bool is_lock_free() const noexcept { return __atomic_impl::is_lock_free<sizeof(_Tp), required_alignment>(); } void store(_Tp __t, memory_order __m = memory_order_seq_cst) const noexcept { __atomic_impl::store(_M_ptr, __t, __m); } _Tp load(memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::load(_M_ptr, __m); } _Tp exchange(_Tp __desired, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::exchange(_M_ptr, __desired, __m); } bool compare_exchange_weak(_Tp& __expected, _Tp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_weak(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Tp& __expected, _Tp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_strong(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Tp& __expected, _Tp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Tp& __expected, _Tp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } value_type fetch_add(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_add(_M_ptr, __i, __m); } value_type fetch_sub(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_sub(_M_ptr, __i, __m); } value_type fetch_and(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_and(_M_ptr, __i, __m); } value_type fetch_or(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_or(_M_ptr, __i, __m); } value_type fetch_xor(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_xor(_M_ptr, __i, __m); } _GLIBCXX_ALWAYS_INLINE value_type operator++(int) const noexcept { return fetch_add(1); } _GLIBCXX_ALWAYS_INLINE value_type operator--(int) const noexcept { return fetch_sub(1); } value_type operator++() const noexcept { return __atomic_impl::__add_fetch(_M_ptr, value_type(1)); } value_type operator--() const noexcept { return __atomic_impl::__sub_fetch(_M_ptr, value_type(1)); } value_type operator+=(value_type __i) const noexcept { return __atomic_impl::__add_fetch(_M_ptr, __i); } value_type operator-=(value_type __i) const noexcept { return __atomic_impl::__sub_fetch(_M_ptr, __i); } value_type operator&=(value_type __i) const noexcept { return __atomic_impl::__and_fetch(_M_ptr, __i); } value_type operator|=(value_type __i) const noexcept { return __atomic_impl::__or_fetch(_M_ptr, __i); } value_type operator^=(value_type __i) const noexcept { return __atomic_impl::__xor_fetch(_M_ptr, __i); } private: _Tp* _M_ptr; }; // base class for atomic_ref<floating-point-type> template<typename _Fp> struct __atomic_ref<_Fp, false, true> { static_assert(is_floating_point_v<_Fp>); public: using value_type = _Fp; using difference_type = value_type; static constexpr bool is_always_lock_free = __atomic_always_lock_free(sizeof(_Fp), 0); static constexpr size_t required_alignment = __alignof__(_Fp); __atomic_ref() = delete; __atomic_ref& operator=(const __atomic_ref&) = delete; explicit __atomic_ref(_Fp& __t) : _M_ptr(&__t) { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); } __atomic_ref(const __atomic_ref&) noexcept = default; _Fp operator=(_Fp __t) const noexcept { this->store(__t); return __t; } operator _Fp() const noexcept { return this->load(); } bool is_lock_free() const noexcept { return __atomic_impl::is_lock_free<sizeof(_Fp), required_alignment>(); } void store(_Fp __t, memory_order __m = memory_order_seq_cst) const noexcept { __atomic_impl::store(_M_ptr, __t, __m); } _Fp load(memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::load(_M_ptr, __m); } _Fp exchange(_Fp __desired, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::exchange(_M_ptr, __desired, __m); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_weak(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_strong(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Fp& __expected, _Fp __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } value_type fetch_add(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::__fetch_add_flt(_M_ptr, __i, __m); } value_type fetch_sub(value_type __i, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::__fetch_sub_flt(_M_ptr, __i, __m); } value_type operator+=(value_type __i) const noexcept { return __atomic_impl::__add_fetch_flt(_M_ptr, __i); } value_type operator-=(value_type __i) const noexcept { return __atomic_impl::__sub_fetch_flt(_M_ptr, __i); } private: _Fp* _M_ptr; }; // base class for atomic_ref<pointer-type> template<typename _Tp> struct __atomic_ref<_Tp*, false, false> { public: using value_type = _Tp*; using difference_type = ptrdiff_t; static constexpr bool is_always_lock_free = ATOMIC_POINTER_LOCK_FREE == 2; static constexpr size_t required_alignment = __alignof__(_Tp*); __atomic_ref() = delete; __atomic_ref& operator=(const __atomic_ref&) = delete; explicit __atomic_ref(_Tp*& __t) : _M_ptr(std::__addressof(__t)) { __glibcxx_assert(((uintptr_t)_M_ptr % required_alignment) == 0); } __atomic_ref(const __atomic_ref&) noexcept = default; _Tp* operator=(_Tp* __t) const noexcept { this->store(__t); return __t; } operator _Tp*() const noexcept { return this->load(); } bool is_lock_free() const noexcept { return __atomic_impl::is_lock_free<sizeof(_Tp*), required_alignment>(); } void store(_Tp* __t, memory_order __m = memory_order_seq_cst) const noexcept { __atomic_impl::store(_M_ptr, __t, __m); } _Tp* load(memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::load(_M_ptr, __m); } _Tp* exchange(_Tp* __desired, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::exchange(_M_ptr, __desired, __m); } bool compare_exchange_weak(_Tp*& __expected, _Tp* __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_weak(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_strong(_Tp*& __expected, _Tp* __desired, memory_order __success, memory_order __failure) const noexcept { return __atomic_impl::compare_exchange_strong(_M_ptr, __expected, __desired, __success, __failure); } bool compare_exchange_weak(_Tp*& __expected, _Tp* __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_weak(__expected, __desired, __order, __cmpexch_failure_order(__order)); } bool compare_exchange_strong(_Tp*& __expected, _Tp* __desired, memory_order __order = memory_order_seq_cst) const noexcept { return compare_exchange_strong(__expected, __desired, __order, __cmpexch_failure_order(__order)); } _GLIBCXX_ALWAYS_INLINE value_type fetch_add(difference_type __d, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_add(_M_ptr, _S_type_size(__d), __m); } _GLIBCXX_ALWAYS_INLINE value_type fetch_sub(difference_type __d, memory_order __m = memory_order_seq_cst) const noexcept { return __atomic_impl::fetch_sub(_M_ptr, _S_type_size(__d), __m); } value_type operator++(int) const noexcept { return fetch_add(1); } value_type operator--(int) const noexcept { return fetch_sub(1); } value_type operator++() const noexcept { return __atomic_impl::__add_fetch(_M_ptr, _S_type_size(1)); } value_type operator--() const noexcept { return __atomic_impl::__sub_fetch(_M_ptr, _S_type_size(1)); } value_type operator+=(difference_type __d) const noexcept { return __atomic_impl::__add_fetch(_M_ptr, _S_type_size(__d)); } value_type operator-=(difference_type __d) const noexcept { return __atomic_impl::__sub_fetch(_M_ptr, _S_type_size(__d)); } private: static constexpr ptrdiff_t _S_type_size(ptrdiff_t __d) noexcept { static_assert(is_object_v<_Tp>); return __d * sizeof(_Tp); } _Tp** _M_ptr; }; #endif // C++2a // @} group atomics _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif