std::memory_order_consume仅仅只用来补充该系列的完整性,在实际代码中不能使用该内存序,且在GCC中会自动将该内存序转换为std::memory_order_acquire。参考至 Fixing GCC's Implementation of memory_order_consumepreshing.com/20141124/fixing-gccs-implementation-of-memory_order_consume/ 1 data dependency介绍...
memory_order_consume是个相对少见的顺序，它仅仅保证依赖于某个值的操作不会被重新排序，但并不保证全局...
1.2 memory_order_consume memory_order_consume适用于load operation,对于采用此内存序的load operation,我们可以称为consume operation,设有一个原子变量M上的consume operation,对周围内存序的影响是:当前线程中该consume operation后的依赖该consume operation读取的值的load 或strore不能被重排到该consume operation前,其...
memory_order_acquire:All writes in other threads that release the same atomic variable are visible in the current thread 初步理解为memory_order_consume会比memory_order_acquire少一些强制依赖关系,或者理解为memory_order_acquire的效果是释放操作后有内存栅设置。 gcc的解释更清晰一些: __ATOMIC_RELAXED No ...
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...
ptr.store(p, std::memory_order_release); } voidconsumer() { std::string* p2; while(!(p2 = ptr.load(std::memory_order_consume))) ; assert(*p2 =="Hello");// never fires: *p2 carries dependency from ptr assert(data == 42);// may or may not fire: data does not carry depende...
memory_order_consume,只约束mutex对象的memory order,不约束上下文中其他变量 a=0;c=0;thread1:{a=1;c.store(3,memory_order_release);}thread2:{//consume只约束mutex对象的memory order,不约束上下文中其他变量while(c.load(memory_order_consume)!=3);assert(a==1);// assert 可能失败也可能不失败} ...
上面Atomic泛型的方法里有个输入参数sync的类型memory_order,用于规约Atomic泛型方法的内存顺序。memory_order在C++11里定义为枚举类型,共有六个值,是C++11定义的内存顺序类型,可供开发者使用: 代码语言:javascript 复制 typedefenummemory_order{memory_order_relaxed,memory_order_consume,memory_order_acquire,memory_ord...
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...
(p2=ptr.load(std::memory_order_consume)));assert(*p2=="Hello");// never fires: *p2 ...