Method startPool

practice/threadpool.cpp:36–50

开启线程池

    // 开启线程池
    void startPool(int size)
    {
        for (int i = 0; i < size; ++ i) {
            // Thread 参数是一个函数对象，可以使用 bind 绑定
            _pool.push_back(new Thread(bind(&ThreadPool::runInThread, this, std::placeholders::_1), i));
        }

        for (int i = 0; i < size; ++ i) {
            _handler.push_back(_pool[i]->start());
        }

        for (thread &t: _handler) {
            t.join();
        }
    }
private:
    vector<Thread *> _pool;
    vector<thread> _handler;