69 lines · cpp
1//2// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.3// See https://llvm.org/LICENSE.txt for license information.4// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception5//6//===----------------------------------------------------------------------===//7 8// UNSUPPORTED: c++03, c++11, c++14, c++179// XFAIL: !has-64-bit-atomics10// XFAIL: !has-1024-bit-atomics11 12// T exchange(T, memory_order = memory_order::seq_cst) const noexcept;13 14#include <atomic>15#include <cassert>16#include <concepts>17#include <type_traits>18 19#include "atomic_helpers.h"20#include "test_helper.h"21#include "test_macros.h"22 23template <typename T>24struct TestExchange {25 void operator()() const {26 {27 T x(T(1));28 std::atomic_ref<T> const a(x);29 30 {31 std::same_as<T> decltype(auto) y = a.exchange(T(2));32 assert(y == T(1));33 ASSERT_NOEXCEPT(a.exchange(T(2)));34 }35 36 {37 std::same_as<T> decltype(auto) y = a.exchange(T(3), std::memory_order_seq_cst);38 assert(y == T(2));39 ASSERT_NOEXCEPT(a.exchange(T(3), std::memory_order_seq_cst));40 }41 }42 43 // memory_order::release44 {45 auto exchange = [](std::atomic_ref<T> const& x, T, T new_val) {46 x.exchange(new_val, std::memory_order::release);47 };48 auto load = [](std::atomic_ref<T> const& x) { return x.load(std::memory_order::acquire); };49 test_acquire_release<T>(exchange, load);50 }51 52 // memory_order::seq_cst53 {54 auto exchange_no_arg = [](std::atomic_ref<T> const& x, T, T new_val) { x.exchange(new_val); };55 auto exchange_with_order = [](std::atomic_ref<T> const& x, T, T new_val) {56 x.exchange(new_val, std::memory_order::seq_cst);57 };58 auto load = [](std::atomic_ref<T> const& x) { return x.load(); };59 test_seq_cst<T>(exchange_no_arg, load);60 test_seq_cst<T>(exchange_with_order, load);61 }62 }63};64 65int main(int, char**) {66 TestEachAtomicType<TestExchange>()();67 return 0;68}69