std::memory_order_acq_rel, or std::memory_order_seq_cst) is dependency-ordered-before a load operation B (with std::memory_order_consume) if the result of load operation B is used in a further operation C in the same thread. It is important to note that operations B and C have to...
memory_order_consume, memory_order_acquire, 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_releas...
y.store(true, std::memory_order_seq_cst); } void read_x_then_y() { while (!x.load(std::memory_order_seq_cst)) { } if (y.load(std::memory_order_seq_cst)) { ++z; } } void read_y_then_x() { while (!y.load(std::memory_order_seq_cst)); if (x.load(std::memory_or...
memory_order_relaxed:没有同步或顺序制约,仅对此操作要求原子性 memory_order_consume:在当前线程中,load操作之后的依赖于此原子变量的读和写操作都不能被重排到当前指令前。如果有其他线程使用memory_order_release内存模型对此原子变量进行store操作,在当前线程中是可见的。 memory_order_acq_rel:等同于对原子变量同...
std::memory_order_acquire(获取顺序):一个载入操作的后续操作(包括对任何变量的读取和写入)不能被重排到该载入操作之前。 std::memory_order_release(释放顺序):一个存储操作的前序操作(包括对任何变量的读取和写入)不能被重排到该存储操作之后。 std::memory_order_acq_rel(获取释放顺序):同时包含 std::memory...
memory_order_release, memory_order_acq_rel, memory_order_seq_cst } memory_order; (C++11 起) (C++20 前) enum class memory_order : /*unspecified*/ { relaxed, consume, acquire, release, acq_rel, seq_cst }; inline constexpr memory_order memory_order_relaxed = memory_order::relaxed; in...
inline constexpr memory_order memory_order_acq_rel = memory_order::acq_rel; inline constexpr memory_order memory_order_seq_cst = memory_order::seq_cst; (C++20 起) std::memory_order 指定内存访问,包括常规的非原子内存访问,如何围绕原子操作排序。在没有任何制约的多处理器系统上,多个线程同时读或...
std::memory_order Defined in header<atomic> enummemory_order { memory_order_relaxed, memory_order_consume, memory_order_acquire, memory_order_release, memory_order_acq_rel, memory_order_seq_cst }; (since C++11) (until C++20) enumclassmemory_order:/* unspecified */ ...
std::memory_order_relaxedstd::memory_order::acquire我相信并且太放松了,因为所有线程counter = 0;最初都会观察,并且我们必须确保data[0] *= 2在第一个之前没有移动fetch_add。这两个内存顺序允许这样做。答案必须是以下之一:std::memory_order::seq_cst std::memory_order::acq_rel std::memory-order::...
memory_order_releaseRelease memory_order_acq_relAcquire/Release memory_order_seq_cstSequentially consistent 另外,如果第二个参数不指定(取默认参数 memory_order_seq_cst),则 fetch_add 相当与 std::atomic::operator+=。 fetch_sub if T is integral (1)T fetch_sub (T val, memory_order sync = memor...