0** this wait loop must use a load-acquire such that we match the* store-release that clears...
读写同步：memory_order_acquire和memory_order_release常用于锁或条件变量等同步场景，适合需要同步读写的...
#include<atomic>std::atomic_intflag(0);// 初始值为零int data=0;// thread 1voidthread_func1(){data=42;flag.store(1,// 事件1std::memory_order_release);}// thread 2voidthread_func2(){int ready=flag.load(// 事件2std::memory_order_acquire);if(ready==1)printf("%d",data);} 要注...
它保证原子变量在设置后立即对所有其他线程可见. 发布-获取顺序(Release-Acquire ordering) Release-Acquire 顺序必须成对使用。它保证原子变量对于获取该变量的线程可见。memory_order_release memory_order_acquire 宽松排序(Relaxed ordering) 宽松排序是最弱的排序,这意味着原子变量最终对其他线程可见,没有时间(排序)保...
memory_order_consume = consume, memory_order_acquire = acquire, memory_order_release = release, memory_order_acq_rel = acq_rel, memory_order_seq_cst = seq_cst }; 所以你可以使用 memory_order::relaxed 代替 memory_order_relaxed,不过因为常量表达式的定义,在 C++ 20 使用 memory_order_relaxed 的...
memory_order_seq_cst,即顺序一致性模型。 Acquire-Release 模式 memory_order_release前面不会被reord到本句之后;memory_order_acquire之后的代码不会被reorder到本句之前;memory_order_acq_rel同时包含acquire和release标志。 这是一段实践代码,代码简单明确:https://www.cnblogs.com/lizhanzhe/p/10893016.html ...
限于篇幅,这里只介绍memory_order_acquire(简称Acquire)和memory_order_release(简称Release)这两种内存顺序,后续再介绍C++的其他内存顺序。 下表给出了Acquire和Release的语义: 即,Acquire要求,针对某个读操作,该读操作之后的读操作或写操作,这两种情况下的指令顺序不能改变; Release要求,针对某个写操作,该写操作之前...
读操作(memory_order_acquire memory_order_consume) 写操作(memory_order_release) 读-修改-写操作(memory_order_acq_rel memory_order_seq_cst) ps: 因为memory_order_relaxed没有定义同步和排序约束,所以它不适合这个分类。 2) 从访问控制的角度可以分为以下三种: ...
memory_order_relaxed, memory_order_consume, memory_order_acquire, memory_order_release, memory_order_acq_rel, memory_order_seq_cst }; 1. 2. 3. 4. 5. 6. 7. 8. 这六个值对应的内存访问序列化方式可分为三类内存访问模型,分别是:宽松的访问序列化模型、获取/释放语义模型和顺序一致性模型。按照...
Acquire-release ordering. 实现同步, 但不保证保证全局顺序一致的模型. Relaxed ordering. 不能实现同步, 只保证原子性的模型. 稍后我们会详细讨论这六种内存顺序.atomic::store和atomic::load函数都有一个内存顺序的参数, 默认为memory_order_seq_cst. 它们的声明如下 ...