涉及知识点

  • mutex
  • lock
  • lamda表达式
  • 队列queue
  • emplace
  • 可变参数
  • 模板函数
  • 万能引用
  • 左值引用
  • 右值引用
  • 完美转发forward
  • 函数适配器bind
  • 时间库chrono

代码

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#include<iostream>
#include<thread>
#include<mutex>
#include<condition_variable>
#include<string>
#include<queue>
#include<vector>
#include<functional>
using namespace std;

class ThreadPool {
public:
ThreadPool(int numThreads): stop(false) {
for (int i = 0; i < numThreads; i++) {
threads.emplace_back([this] {
while (1) {
function<void()> task;
{
unique_lock<mutex> lock(mtx);
condition.wait(lock, [this] {
return !tasks.empty() || stop;
});
if (stop && tasks.empty()) {
return;
}
task = move(tasks.front());
tasks.pop();
}
task();
}
});
}
}

~ThreadPool() {
{
unique_lock<mutex> lock(mtx);
stop = true;
}
condition.notify_all();
for (auto& t : threads) {
t.join();
}
}
template<class F, class... Args>
void enqueue(F && f, Args&&... args) {
function<void()>task = bind(forward<F>(f), forward<Args>(args)...);
{
unique_lock<mutex> lock(mtx);
tasks.emplace(move(task));
}
condition.notify_one();
}
private:
vector<thread> threads;
queue<function<void()> > tasks;

mutex mtx;
condition_variable condition;

bool stop;
};


int main()
{
ThreadPool pool(4);

for (int i = 0; i < 12; i++) {
pool.enqueue([i] {
cout << "task : " << i << "is running !"<<endl;
this_thread::sleep_for(chrono::seconds(2));
cout << "task : " << i << "is close !" << endl;
});
}

return 0;
}