std::memory_order_release);// 发布数据}voidconsumer(){while(flag.load(std::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; 考虑到避免版本差异的陷阱,使用 memory_order_relaxed 是一个稳妥的...
std::memory_order_release)和thread_func2里flag.load(std::memory_order_acquire)来确保); 如果在运行时,事件2 Happen-Before事件1, 那基于flag这个原子变量的原子操作和内存顺序的实现无法确保事件2和事件1之间有Synchronize-With关系,
y=0;voidthread_func1(){x=y+1;// 通知thread_func2indicator.store(1,// 写操作std::memory_order_release);}voidthread_func2(){int ready=indicator.load(// 读操作std::memory_order_acquire);// 等待thread_func1if(read>0){y=2;}}
在这之后,别的cpu执行memory_order_acquire,都可以看到这个cpu所做的memory修改。 memory_order_acq_rel 是memory_order_acquire和memory_order_release的合并,这条语句前后的语句都不能被reorder。 memory_order_seq_cst 这是比memory_order_acq_rel更加严格的顺序保证,memory_order_seq_cst执行完毕后,所有其cpu都...
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...
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_release, memory_order_acq_rel, memory_order_seq_cst }; 上述6 中访存次序(内存序)分为 3 类,顺序一致性模型(std::memory_order_seq_cst),Acquire-Release 模型(std::memory_order_consume, std::memory_order_acquire, std::memory_order_release, std::memory_order_acq_rel,) (获取/释...
序列一致顺序(Sequential consistency):原子操作带上memory_order_seq_cst参数,这也是C++标准库的默认顺序,也是执行代价最大的,它是memory_order_acq_rel的加强版,如果是读取就是 acquire语义,如果是写入就是 release 语义,且全部读写操作顺序均一致。 下面代码中value = 100不允许被移动到readFlag.store(true, memo...
typedefenum{memory_order_relaxed=__ATOMIC_RELAXED,memory_order_consume=__ATOMIC_CONSUME,memory_order_acquire=__ATOMIC_ACQUIRE,memory_order_release=__ATOMIC_RELEASE,memory_order_acq_rel=__ATOMIC_ACQ_REL,memory_order_seq_cst=__ATOMIC_SEQ_CST}memory_order; ...