compare_exchange_weak bool compare_exchange_weak( T& expected, T desired, std::memory_order success, std::memory_order failure ); bool compare_exchange_weak( T& expected, T desired, std::memory_order success, std::memory_order failure ) volatile; bool compare_exchange_weak( T& expected, ...
2.6、compare_exchange_weak函数 2.7、compare_exchange_strong函数 2.8、专业化支持的操作 三、使用示例 总结 一、简介 C++中原子变量(atomic)是一种多线程编程中常用的同步机制,它能够确保对共享变量的操作在执行时不会被其他线程的操作干扰,从而避免竞态条件(race condition)和死锁(deadlock)等问题。 原子变量可以看...
函数原型: bool compare_exchange_weak(T&expected, T desired, std::memory_order success, std::memory_order failure);bool compare_exchange_weak(T&expected, T desired, std::memory_order success, std::memory_order failure)volatile;bool compare_exchange_weak(T&expected, T desired, std::memory_ord...
在循环中进行比较和交换时,compare_exchange_weak 在有的平台上会产出更好的性能。 当compare_exchange_weak 比较和交换会要求循环,而 compare_exchange_strong 不要求时,推荐用 std::compare_exchange_strong,除非 T 的对象表示可包含填充位、(C++20 前)陷阱位或为同一值提供多个对象表示(例如浮点 NaN)。这些...
我将给出一个例子，因为它非常简单，所以我确实使用了它。
head.compare_exchange_weak(old_head, new_node, // std::memory_order_release, // std::memory_order_relaxed)); } }; int main() { stack<int> s; s.push(1); s.push(2); s.push(3); }演示compare_exchange_strong 如何要么更改原子对象的值,要么将变量用于比较。
std::atomic_compare_exchange_weak_explicit( &head, &new_node->next, new_node,std::memory_order_release,std::memory_order_relaxed)) ; // 循环体为空 // 注意:上述循环非线程安全,至少在 // 早于 4.8.3 的 GCC ( bug 60272 ),早于 2014-05-05 的 clang ( bug 18899) // 早于 2014-03...
The weak forms (1,2) of the functions are allowed to fail spuriously, that is, act as if *this != expected even if they are equal. When a compare-and-exchange is in a loop, the weak version will yield better performance on some platforms. When a weak compare-and-exchange would re...
compare_exchange_weakcompare_exchange_strong 原子地比较原子对象与非原子参数的值,若相等则进行交换,若不相等则进行加载 (std::atomic<T>的公开成员函数) atomic_exchangeatomic_exchange_explicit (C++11)(C++11) 原子地以非原子实参的值替换原子对象的值,并返回该原子对象的旧值 ...
std::atomic<T>::compare_exchange_weak,std::atomic<T>::compare_exchange_strong C++ Concurrency support library std::atomic boolcompare_exchange_weak(T&expected, T desired, std::memory_ordersuccess, std::memory_orderfailure)noexcept; (1)(since C++11) ...