一份C++线程池的代码，非常实用

#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.csdn.net/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。
3. 线程池有一个EndAndWait函数，用于让线程池中所有计算正常结束。有时线程池中的一个线程可能要运行很长时间，怎么办？可以通过线程函数threadfunc的入口参数对象来处理，比如：
class YourClass {
int cmd; // cmd = 1是上线程停止计算，正常退出。
};
threadfunc(void* p) {
YourClass* yourObject = (YourClass*)p;
while (true) {
// do some calculation
if (yourClass->cmd == 1)
break;
}
}
在主线程中设置yourClass->cmd = 1，该线程就会自然结束。
很简洁通用的线程池实现。