};//而__atomic_flag_data_type是这样的#if__GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1typedefbool__atomic_flag_data_type;#elsetypedefunsignedchar__atomic_flag_data_type;#endif //我们可以看到atomic<bool>是atomic泛型的一个特化template<>structatomic<bool> {private: __atomic_base<bool> _M_base; ...
typedefbool__atomic_flag_data_type; #else typedefunsignedchar__atomic_flag_data_type; #endif 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. //我们可以看到atomic<bool>是atomic泛型的一个特化 template<> structatomic<bool> { private: __atomic_base<bool>_M_base...
将存储在 *this 中的bool 标志设置为 true(限于指定的 memory_order 约束)。C++ 复制 bool atomic_flag::test_and_set(memory_order Order = memory_order_seq_cst) volatile noexcept; bool atomic_flag::test_and_set(memory_order Order = memory_order_seq_cst) noexcept; ...
set atomic_flag,并且返回调用该函数之前atomic_flag是否被set。 bool test_and_set (memory_order sync = memory_order_seq_cst) volatile noexcept; bool test_and_set (memory_order sync = memory_order_seq_cst) noexcept; // atomic_flag as a spinning lock #include <iostream> // std::cout #incl...
std::atomic_flag是原子布尔类型。不同于所有std::atomic的特化,它保证是免锁的。不同于std::atomic<bool>,std::atomic_flag不提供加载或存储操作。 成员函数 (构造函数) 构造atomic_flag (公开成员函数) operator= 赋值运算符 (公开成员函数) clear ...
bool atomic_flag::test_and_set(memory_orderorder= memory_order_seq_cst) noexcept; Parameter order The memory order constraints to enforce. Return value Returns the value of the object immediately before the update.
}booltry_lock() {return!m_lock.test_and_set(std::memory_order_acquire); }voidunlock() { m_lock.clear(std::memory_order_release); }private: std::atomic_flag m_lock; };#endif//_SPINLOCK_H_20170410_ root@ubuntu:~/c++# cat spinlock.cpp ...
所以std::atomic就不能保证无锁。但是当T是bool或者int的时候就可以通过特定的cpu指令来保证操作在cpu...
atomic_flag 是一种原子布尔类型。不同于其他原子类型,它保证是免锁的。不同于 atomic_bool, atomic_flag 不提供加载或存储操作。 引用C11 standard (ISO/IEC 9899:2011): 7.17.1/4 atomic_flag (p: 273) 7.17.8 Atomic flag type and operations (p: 285-286) ...
(true,std::memory_order_relaxed)#endif;}booltry_lock()noexcept{return!m_.test_and_set(std::memory_order_acquire);}voidunlock()noexcept{m_.clear(std::memory_order_release);#if defined(__cpp_lib_atomic_wait) && __cpp_lib_atomic_wait >= 201907Lm_.notify_one();#endif}};staticmutex ...