32 lines
745 B
C++
32 lines
745 B
C++
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#include <vector>
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#include <iostream>
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#include <thread>
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#include <atomic>
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std::atomic<int> cnt = { 0 };
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void f()
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{
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for (int n = 0; n < 1000; ++n) {
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cnt.fetch_add(1, std::memory_order_relaxed);
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}
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}
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int main()
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{
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std::vector<std::thread> v;
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for (int n = 0; n < 10; ++n) {
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v.emplace_back(f);
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}
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for (auto& t : v) {
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t.join();
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}
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std::cout << "Final counter value is " << cnt << '\n';
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}
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/*
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* 带标签 memory_order_relaxed 的原子操作不是同步操作；它们不会为并发的内存访问行为添加顺序约束。它们只保证原子性和修改顺序的一致性。
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*
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* 宽松内存顺序的典型的应用是计数器自增，只要求原子性，但不要求顺序或同步
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*
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*/
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