转载一份C++线程池的代码，非常实用

最新推荐文章于 2023-04-27 19:20:11 发布

转载最新推荐文章于 2023-04-27 19:20:11 发布 · 1.5k 阅读

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本文介绍了一个基于Windows API实现的线程池类，可用于多线程下载等应用场景。提供了线程池的创建、调整大小、调用及结束等功能，并通过示例展示了如何使用。

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#ifndef _ThreadPool_H_ #define _ThreadPool_H_ #pragma warning(disable: 4530) #pragma warning(disable: 4786) #include <cassert> #include <vector> #include <queue> #include <windows.h> using namespace std; class ThreadJob //工作基类 { public: //供线程池调用的虚函数 virtual void DoJob(void *pPara) = 0; }; class ThreadPool { public: //dwNum 线程池规模 ThreadPool(DWORD dwNum = 4) : _lThreadNum(0), _lRunningNum(0) { InitializeCriticalSection(&_csThreadVector); InitializeCriticalSection(&_csWorkQueue); _EventComplete = CreateEvent(0, false, false, NULL); _EventEnd = CreateEvent(0, true, false, NULL); _SemaphoreCall = CreateSemaphore(0, 0, 0x7FFFFFFF, NULL); _SemaphoreDel = CreateSemaphore(0, 0, 0x7FFFFFFF, NULL); assert(_SemaphoreCall != INVALID_HANDLE_VALUE); assert(_EventComplete != INVALID_HANDLE_VALUE); assert(_EventEnd != INVALID_HANDLE_VALUE); assert(_SemaphoreDel != INVALID_HANDLE_VALUE); AdjustSize(dwNum <= 0 ? 4 : dwNum); } ~ThreadPool() { DeleteCriticalSection(&_csWorkQueue); CloseHandle(_EventEnd); CloseHandle(_EventComplete); CloseHandle(_SemaphoreCall); CloseHandle(_SemaphoreDel); vector<ThreadItem*>::iterator iter; for(iter = _ThreadVector.begin(); iter != _ThreadVector.end(); iter++) { if(*iter) delete *iter; } DeleteCriticalSection(&_csThreadVector); } //调整线程池规模 int AdjustSize(int iNum) { if(iNum > 0) { ThreadItem *pNew; EnterCriticalSection(&_csThreadVector); for(int _i=0; _i<iNum; _i++) { _ThreadVector.push_back(pNew = new ThreadItem(this)); assert(pNew); pNew->_Handle = CreateThread(NULL, 0, DefaultJobProc, pNew, 0, NULL); // set priority SetThreadPriority(pNew->_Handle, THREAD_PRIORITY_BELOW_NORMAL); assert(pNew->_Handle); } LeaveCriticalSection(&_csThreadVector); } else { iNum *= -1; ReleaseSemaphore(_SemaphoreDel, iNum > _lThreadNum ? _lThreadNum : iNum, NULL); } return (int)_lThreadNum; } //调用线程池 void Call(void (*pFunc)(void *), void *pPara = NULL) { assert(pFunc); EnterCriticalSection(&_csWorkQueue); _JobQueue.push(new JobItem(pFunc, pPara)); LeaveCriticalSection(&_csWorkQueue); ReleaseSemaphore(_SemaphoreCall, 1, NULL); } //调用线程池 inline void Call(ThreadJob * p, void *pPara = NULL) { Call(CallProc, new CallProcPara(p, pPara)); } //结束线程池, 并同步等待 bool EndAndWait(DWORD dwWaitTime = INFINITE) { SetEvent(_EventEnd); return WaitForSingleObject(_EventComplete, dwWaitTime) == WAIT_OBJECT_0; } //结束线程池 inline void End() { SetEvent(_EventEnd); } inline DWORD Size() { return (DWORD)_lThreadNum; } inline DWORD GetRunningSize() { return (DWORD)_lRunningNum; } bool IsRunning() { return _lRunningNum > 0; } protected: //工作线程 static DWORD WINAPI DefaultJobProc(LPVOID lpParameter = NULL) { ThreadItem *pThread = static_cast<ThreadItem*>(lpParameter); assert(pThread); ThreadPool *pThreadPoolObj = pThread->_pThis; assert(pThreadPoolObj); InterlockedIncrement(&pThreadPoolObj->_lThreadNum); HANDLE hWaitHandle[3]; hWaitHandle[0] = pThreadPoolObj->_SemaphoreCall; hWaitHandle[1] = pThreadPoolObj->_SemaphoreDel; hWaitHandle[2] = pThreadPoolObj->_EventEnd; JobItem *pJob; bool fHasJob; for(;;) { DWORD wr = WaitForMultipleObjects(3, hWaitHandle, false, INFINITE); //响应删除线程信号 if(wr == WAIT_OBJECT_0 + 1) break; //从队列里取得用户作业 EnterCriticalSection(&pThreadPoolObj->_csWorkQueue); if(fHasJob = !pThreadPoolObj->_JobQueue.empty()) { pJob = pThreadPoolObj->_JobQueue.front(); pThreadPoolObj->_JobQueue.pop(); assert(pJob); } LeaveCriticalSection(&pThreadPoolObj->_csWorkQueue); //受到结束线程信号确定是否结束线程(结束线程信号 && 是否还有工作) if(wr == WAIT_OBJECT_0 + 2 && !fHasJob) break; if(fHasJob && pJob) { InterlockedIncrement(&pThreadPoolObj->_lRunningNum); pThread->_dwLastBeginTime = GetTickCount(); pThread->_dwCount++; pThread->_fIsRunning = true; pJob->_pFunc(pJob->_pPara); //运行用户作业 delete pJob; pThread->_fIsRunning = false; InterlockedDecrement(&pThreadPoolObj->_lRunningNum); } } //删除自身结构 EnterCriticalSection(&pThreadPoolObj->_csThreadVector); pThreadPoolObj->_ThreadVector.erase(find(pThreadPoolObj->_ThreadVector.begin(), pThreadPoolObj->_ThreadVector.end(), pThread)); LeaveCriticalSection(&pThreadPoolObj->_csThreadVector); delete pThread; InterlockedDecrement(&pThreadPoolObj->_lThreadNum); if(!pThreadPoolObj->_lThreadNum) //所有线程结束 SetEvent(pThreadPoolObj->_EventComplete); return 0; } //调用用户对象虚函数 static void CallProc(void *pPara) { CallProcPara *cp = static_cast<CallProcPara *>(pPara); assert(cp); if(cp) { cp->_pObj->DoJob(cp->_pPara); delete cp; } } //用户对象结构 struct CallProcPara { ThreadJob* _pObj;//用户对象 void *_pPara;//用户参数 CallProcPara(ThreadJob* p, void *pPara) : _pObj(p), _pPara(pPara) { }; }; //用户函数结构 struct JobItem { void (*_pFunc)(void *);//函数 void *_pPara; //参数 JobItem(void (*pFunc)(void *) = NULL, void *pPara = NULL) : _pFunc(pFunc), _pPara(pPara) { }; }; //线程池中的线程结构 struct ThreadItem { HANDLE _Handle; //线程句柄 ThreadPool *_pThis; //线程池的指针 DWORD _dwLastBeginTime; //最后一次运行开始时间 DWORD _dwCount; //运行次数 bool _fIsRunning; ThreadItem(ThreadPool *pthis) : _pThis(pthis), _Handle(NULL), _dwLastBeginTime(0), _dwCount(0), _fIsRunning(false) { }; ~ThreadItem() { if(_Handle) { CloseHandle(_Handle); _Handle = NULL; } } }; std::queue<JobItem *> _JobQueue; //工作队列 std::vector<ThreadItem *> _ThreadVector; //线程数据 CRITICAL_SECTION _csThreadVector, _csWorkQueue; //工作队列临界, 线程数据临界 HANDLE _EventEnd, _EventComplete, _SemaphoreCall, _SemaphoreDel;//结束通知, 完成事件, 工作信号，删除线程信号 long _lThreadNum, _lRunningNum; //线程数, 运行的线程数 }; #endif //_ThreadPool_H_

转载自 http://blog.youkuaiyun.com/pjchen/archive/2004/11/06/170606.aspx

基本上是拿来就用了，对WIN32 API不熟，但对线程池的逻辑还是比较熟的，认为这个线程池写得很清晰，我拿来用在一个多线程下载的模块中。很实用的东东。

调用方法

void threadfunc(void *p)

{

YourClass* yourObject = (YourClass*) p;

//...
}
ThreadPool tp;
for(i=0; i<100; i++)
tp.Call(threadfunc);

ThreadPool tp(20);//20为初始线程池规模

tp.Call(threadfunc, lpPara);

使用时注意几点：

1. ThreadJob 没什么用，直接写线程函数吧。

2. 线程函数（threadfunc）的入口参数void* 可以转成自定义的类型对象，这个对象可以记录下线程运行中的数据，并设置线程当前状态，以此与线程进行交互。