56 lines
1.4 KiB
C++
56 lines
1.4 KiB
C++
#include <iostream>
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#include <condition_variable>
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#include <thread>
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#include <queue>
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using namespace std;
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#define LOOP_TIMES 50
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void test1() {
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int res = 0, fake_count = 0;
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mutex mtx;
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condition_variable cv;
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queue<int> mq;
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thread t1([&]() {
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for (int i = 0; i < LOOP_TIMES * 2; i++) {
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this_thread::sleep_for(chrono::milliseconds(i));
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//unique_lock<mutex> lock(mtx);
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mq.push(i / 4);
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//std::cout << "notify one " << i << " " << res << "\n";
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cv.notify_all();
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res = res + 1;
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}
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});
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auto consume_fn = [&]() {
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for (int i = 0; i < LOOP_TIMES; i++) {
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this_thread::sleep_for(chrono::milliseconds(i));
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unique_lock<mutex> lock(mtx);
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while (mq.empty()) {
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fake_count++;
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//std::cout << "wait one " << i << " " << res << " " << fake_count << "\n";
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cv.wait(lock);
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}
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//std::cout << "handle one " << i << " " << res << "\n";
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mq.pop();
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}
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};
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thread t2(consume_fn);
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thread t3(consume_fn);
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t1.join();
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t2.join();
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t3.join();
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std::cout << "test3:: res:: " << res << " fake_count:: " << fake_count << " condition_variable:: size " << sizeof(cv) << endl;
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}
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int main() {
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test1();
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/*
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条件变量：
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wait(unique_lock<mutex>);
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unlock 解锁
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wait cond 等待其他线程唤醒
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lock 上锁（可能会阻塞）
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notify_one 唤醒一个线程
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虚假唤醒，条件变量只负责通知线程抢夺资源，并不保证一定能分配（抢到）资源
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*/
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return 1;
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} |