C++学习记录：从一个小线程池源码看C++11新特性的优雅使用

2023-11-01 12:11:41

最近抽空学习一些感兴趣的源码，这次学习一个小而美的C++11线程池源码。核心代码很简单，就是下面这不到一百行。但是其中使用了很多新C++11的新东西，写的非常优雅，有很多可以学习的地方。

#include <iostream>
#include <thread>
#include <vector>
#include <mutex>
#include <condition_variable>

class ThreadPool {
public:
    ThreadPool(int num_threads) : num_threads_(num_threads) {
        for (int i = 0; i < num_threads_; ++i) {
            threads_.emplace_back([this] {
                while (true) {
                    std::unique_lock<std::mutex> lock(mutex_);
                    if (tasks_.empty()) {
                        cv_.wait(lock);
                    }
                    auto task = std::move(tasks_.front());
                    tasks_.pop();
                    lock.unlock();
                    task();
                }
            });
        }
    }

    ~ThreadPool() {
        {
            std::lock_guard<std::mutex> lock(mutex_);
            stop_ = true;
            cv_.notify_all();
        }
        for (auto& thread : threads_) {
            thread.join();
        }
    }

    void addTask(std::function<void()> task) {
        std::lock_guard<std::mutex> lock(mutex_);
        tasks_.push(std::move(task));
        cv_.notify_one();
    }

private:
    std::vector<std::thread> threads_;
    std::mutex mutex_;
    std::condition_variable cv_;
    std::queue<std::function<void()>> tasks_;
    bool stop_ = false;
    int num_threads_;
};

int main() {
    ThreadPool pool(4);
    for (int i = 0; i < 10; ++i) {
        pool.addTask([i] {
            std::cout << "Task " << i << " is running." << std::endl;
        });
    }

    return 0;
}