#include<iostream> // std::cout#include<atomic> // std::atomic#include<thread> // s...
T atomic_exchange_explicit(volatilestd::atomic<T>*obj, typenamestd::atomic<T>::value_typedesired, std::memory_orderorder)noexcept; (4)(C++11 起) 1,2)如同用obj->exchange(desired)以desired的值原子地替換obj指向的值,並返回obj先前保有的值。
在C++中，`std::atomic::compare_exchange`函数的选择主要基于业务需求和数据对象的特性。选择`strong`版本的比较与交换操作，通常意味着在比较不匹配时不需要循环，这是更优的选择，除非数据类型`T`的表示可能包含填充位、陷阱位或提供相同值的不同对象表示（如浮点数的NaN）。在这些情况下，弱比较与交...
Atomic operations libraryATOMIC_FLAG_INITATOMIC_VAR_INITATOMIC_xxx_LOCK_FREEstd::atomicstd::atomic::atomicstd::atomic::compare_exchange_strongstd::atomic::compare_exchange_weakstd::atomic::exchangestd::atomic::fetch_addstd::atomic::fetch_andstd::atomic::fetch_orstd::atomic::fetch_substd::atomi...
ATOMIC_xxx_LOCK_FREE std::atomic std::atomic::atomic std::atomic::compare_exchange_strong std::atomic::compare_exchange_weak std::atomic::exchange std::atomic::fetch_add std::atomic::fetch_and std::atomic::fetch_or std::atomic::fetch_sub ...
std::atomic<T>::is_lock_free std::atomic<T>::is_always_lock_free std::atomic<T>::store std::atomic<T>::load std::atomic<T>::operator T() std::atomic<T>::exchange std::atomic<T>::compare_exchange_weak, std::atomic<T>::compare_exchange_strong std::atomic<T>::wait std::ato...
Something likehttps://en.cppreference.com/w/cpp/atomic/atomic_exchange If at return of such function the value of the counter already increased it is not a problem, but it is important that the load and store of the counter value happen atomically ...
std::atomic Member functions atomic::atomic atomic::operator= atomic::is_lock_free atomic::store atomic::load atomic::operator T atomic::exchange atomic::compare_exchange_strongatomic::compare_exchange_weak atomic::wait (C++20) atomic::notify_one ...
template< class T > T exchange( volatile std::atomic<T>* obj, T desired ); 其中,obj参数指向需要替换值的atomic对象,desired参数为期望替换成的值。如果替换成功,则返回原来的值。 整个操作是原子的(原子读-修改-写操作):从读取(要返回)值的那一刻到此函数修改值的那一刻,该值不受其他线程的影响。
演示std::compare_exchange_strong 如何要么更改原子对象的值,要么将变量用于比较。 本节未完成原因:强 CAS 的更实际用法会更好,例如在 Concurrency in Action 使用它的地方 运行此代码#include <atomic> #include <iostream>std::atomic<int> ai;int