#include <iostream> #include <thread> #include <atomic> std::atomic<long long> data; void do_work() { data.fetch_add(1, std::memory_order_relaxed); } int main() { std::thread th1(do_work); std::thread th2(do_work); std::thread th3(do_work); std::thread th4(do_work); ...
C++11为了充分发挥计算的特长,针对非浮点数值(std::atmoic<integral>)及指针(std::atomic<T*>)进行了特化,以提高原子操作的性能。特化后的atomic在通用操作的基础上,还提供了更丰富的功能。 3.1 fetch_add //T is integralT fetch_add(T v, memory_order m = memory_order_seq_cst)volatilenoexcept; T f...
T atomic_fetch_add_explicit( std::atomic<T>* obj, typename std::atomic<T>::difference_type arg, std::memory_order order ) noexcept; template< class T > T atomic_fetch_add_explicit( volatile std::atomic<T>* obj, typename std::atomic<T>::difference_type arg, std::memory_order ...
#include <iostream> #include <thread> #include <atomic> std::atomic<long long> data; void do_work() { data.fetch_add(1, std::memory_order_relaxed); } int main() { std::thread th1(do_work); std::thread th2(do_work); std::thread th3(do_work); std::thread th4(do_work); ...
#include <atomic> int main(int argc,char**argv) { std::atomic<int> x(10); std::cout << std::boolalpha << "std::atomic<int> is_lock_free ?\n" << x.is_lock_free() << std::endl; return 0; }输出:std::atomic<int> is_lock_free ? trueload...
#include<iostream>#include<thread>#include<atomic>std::atomic<long long>data;voiddo_work(){data.fetch_add(1,std::memory_order_relaxed);}intmain(){std::threadth1(do_work);std::threadth2(do_work);std::threadth3(do_work);std::threadth4(do_work);std::threadth5(do_work);th1.join(...
std::atomic_int x{1};x.fetch_add(1);// 原子操作x+=1;// 原子操作x=x+1;// 非原子操作 图解: 2.std::atomic并非总是无锁的 无锁(lock-free)是std::atomic的重要特性之一,但并非所有std::atomic对象都能实现无锁操作。是否无锁依赖于以下因素: ...
例如:#include <atomic> std::atomic_int counter = 0; void foo(int *data, int size) { // we could also write counter++ for (int i; (i = counter.fetch_add(1, std::memory_order::seq_cst)) < size;) { data[i] *= 2; } } ...
T fetch_add(T arg, std::memory_orderorder=std::memory_order_seq_cst)constnoexcept; (1)(since C++20) member only ofatomic_ref<T*>template specialization T*fetch_add(std::ptrdiff_targ, std::memory_orderorder=std::memory_order_seq_cst)constnoexcept; ...
原子读写操作:std::atomic提供了原子读写操作,如load()、store()等。这些操作可以保证数据在多线程环境中的一致性。 原子算术和位操作:std::atomic还提供了一系列原子算术和位操作,如fetch_add()、fetch_and()等。这些操作可以实现对数据的原子性修改。