C++ 简单的线程池 thread_pool

#include "stdafx.h"

#include

#include "ThreadPool.h" //主要的是这文件哦，基本上找到这个文件就成功了

using namespace std;

struct BlockResult // 结构体做线程参数用的

{

int a;

int b;

int c;

void reset(void)

{

a = 0;

b = 0;

c = 0;

}

void prn(void)

{

std::cout << "a: " << a << "b: " << b << "c: " << c << std::endl;

}

};

int single_block_main(BlockResult *br) //线程运行的函数

{

int i=0;

while (i++ < 3)

{

std::cout << "Current Thread ID: " << std::this_thread::get_id() << std::endl;

_sleep(1000);

}

return 0;

}

int main()

{

int blk_num = 2;

ThreadPool workers(thread::hardware_concurrency()); //创建线程池

BlockResult *brs = new BlockResult[blk_num];//参数分配内存

for (int i = 0; i < blk_num; i++)
{
brs[i].reset();//复位
brs[i].addr = i;
}

vector <::future > results; //使用容器里面是回到的函数

for (int i = 0; i < blk_num; i++)

{

results.emplace_back(workers.enqueue(single_block_main, brs + i));

}

for (auto && result : results)

{

int addr = result.get();//线程结束时获取地址

brs[addr].prn();

}

delete[] brs;

system("suspend");

    return 0;

}

把ThreadPool.h的代码贴出来吧

#ifndef THREAD_POOL_H__
#define THREAD_POOL_H__

#include
#include
#include
#include
#include
#include
#include
#include

class ThreadPool
{
public:
    ThreadPool(size_t);
    template
    auto enqueue(F&& f, Args&&... args)
    ->std::future::type>;
    ~ThreadPool();
private:
    // need to keep track of threads so we can join them
    std::vector< std::thread > workers;
    // the task queue
    std::queue< std::function > tasks;


    // synchronization
    std::mutex queue_mutex;
    std::condition_variable condition;
    bool stop;
};

// the constructor just launches some amount of workers
inline ThreadPool::ThreadPool(size_t threads)
    : stop(false)
{
    for (size_t i = 0; i < threads; ++i)
        workers.emplace_back(
            [this]
    {
        for (;;)
        {
            std::function task;

            {
                std::unique_lock lock(this->queue_mutex);
                this->condition.wait(lock,
                [this] { return this->stop || !this->tasks.empty(); });
                if (this->stop && this->tasks.empty())
                    return;
                task = std::move(this->tasks.front());
                this->tasks.pop();
            }

            task();
        }
    }
    );
}

// add new work item to the pool
template
auto ThreadPool::enqueue(F&& f, Args&&... args)
-> std::future::type>
{
    using return_type = typename std::result_of::type;


    auto task = std::make_shared< std::packaged_task >(
        std::bind(std::forward(f), std::forward(args)...)
    );

    std::future res = task->get_future();
    {
        std::unique_lock lock(queue_mutex);


        // don't allow enqueueing after stopping the pool
        if (stop)
            throw std::runtime_error("enqueue on stopped ThreadPool");


        tasks.emplace([task]() { (*task)(); });
    }
    condition.notify_one();
    return res;
}

// the destructor joins all threads
inline ThreadPool::~ThreadPool()
{
    {
        std::unique_lock lock(queue_mutex);
        stop = true;
    }
    condition.notify_all();
    for (std::thread &worker : workers)
        worker.join();
}

#endif