c++编写简单线程池
先上代码：
#include <iostream>#include <vector>#include <windows.h>using namespace std;#define WM_THREADSTART WM_USER+1#define WM_THREADEND WM_USER+2#define WM_THREADADD WM_USER+3#define WM_THREADPOOLEND WM_USER+4#define WM_THREADPOOLIDIL WM_USER+5class CThreadPool{public:typedef DWORD (WINAPI *ThreadFunc)(LPVOID);typedef struct _sThread{HANDLE m_hThread;ThreadFunc m_fFunc;void* m_vParam;DWORD m_dRetval;}sThread,*spThread;typedef void (*CallBackFunc)(UINT,spThread);CThreadPool();~CThreadPool();void AddTask(ThreadFunc,LPVOID,bool=0 );void Init(CallBackFunc,int=10000);DWORD GetRunThreadCount();spThread GetRunThreadItem(int);DWORD GetWaitThreadCount();spThread GetWaitThreadItem(int);private:static DWORD WINAPI Thread(LPVOID);DWORD m_iThread;HANDLE m_hThread;CallBackFunc m_fFunc;DWORD m_nMaxThreadCount;vector<spThread> m_qRun;vector<spThread> m_qWait;HANDLE m_hEvent;CRITICAL_SECTION m_cs;};CThreadPool::CThreadPool(){m_iThread=0;m_fFunc=0;m_hThread=0;InitializeCriticalSection(&m_cs);}CThreadPool::~CThreadPool(){PostThreadMessage(m_iThread,WM_THREADPOOLEND,0,0);WaitForSingleObject(m_hThread,-1);CloseHandle(m_hThread);LeaveCriticalSection(&m_cs);int i;for(i=0;i<m_qRun.size();i++){delete m_qRun[i];}for(i=0;i<m_qWait.size();i++){delete m_qWait[i];}}void CThreadPool::AddTask(ThreadFunc func,LPVOID lp,bool bImme){if(!bImme){PostThreadMessage(m_iThread,WM_THREADADD,(WPARAM)func,(LPARAM)lp);}else{spThread sTh=new sThread;sTh->m_dRetval=0;sTh->m_hThread=0;sTh->m_fFunc=func;sTh->m_vParam=lp;EnterCriticalSection(&m_cs);m_qWait.insert(m_qWait.begin(),sTh);LeaveCriticalSection(&m_cs);}PostThreadMessage(m_iThread,WM_THREADPOOLIDIL,0,0);}void CThreadPool::Init(CallBackFunc func,int count/* =10000 */){if(func!=NULL)m_fFunc=func;if(count>0) m_nMaxThreadCount=count;m_hEvent=CreateEvent(0,TRUE,FALSE,0);m_hThread=CreateThread(0,0,Thread,this,0,&m_iThread);WaitForSingleObject(m_hEvent,-1);CloseHandle(m_hEvent);}DWORD WINAPI CThreadPool::Thread(LPVOID lp){CThreadPool* pThPool=(CThreadPool*)lp;DWORD dwCurId=GetCurrentThreadId();MSG msg;PeekMessage(&msg,0,WM_USER,WM_USER,PM_NOREMOVE);SetEvent(pThPool->m_hEvent);while (1){Sleep(1);if(PeekMessage(&msg,0,WM_THREADSTART,WM_THREADPOOLIDIL,PM_REMOVE)){switch (msg.message){case WM_THREADPOOLEND:{return true;}case WM_THREADSTART:{spThread sTh=(spThread)msg.wParam;sTh->m_hThread=CreateThread(0,0,sTh->m_fFunc,sTh->m_vParam,0,0);if(pThPool->m_fFunc) pThPool->m_fFunc(WM_THREADSTART,sTh);break;}case WM_THREADEND:{spThread sTh=(spThread)msg.wParam;if(pThPool->m_fFunc) pThPool->m_fFunc(WM_THREADEND,sTh);delete sTh;CloseHandle(sTh->m_hThread);break;}case WM_THREADADD:{CThreadPool::spThread sTh=new CThreadPool::sThread;sTh->m_dRetval=0;sTh->m_hThread=0;sTh->m_fFunc=(ThreadFunc)msg.wParam;sTh->m_vParam=(LPVOID)msg.lParam;EnterCriticalSection(&(pThPool->m_cs));pThPool->m_qWait.push_back(sTh); LeaveCriticalSection(&(pThPool->m_cs));break;}case WM_THREADPOOLIDIL:{goto IDIL;}}}else{IDIL:vector<CThreadPool::spThread> &vObj=pThPool->m_qRun;for(int i=0;i<vObj.size();i++){DWORD iExitCode;GetExitCodeThread(vObj[i]->m_hThread,&iExitCode);if(iExitCode!=STILL_ACTIVE){vObj[i]->m_dRetval=iExitCode;PostThreadMessage(dwCurId,WM_THREADEND,(WPARAM)vObj[i],0);vObj.erase(vObj.begin()+i);i--;}}if(vObj.size()<pThPool->m_nMaxThreadCount){int nCount=pThPool->m_nMaxThreadCount-vObj.size();while(nCount){if(pThPool->m_qWait.size()>0){EnterCriticalSection(&(pThPool->m_cs));vObj.push_back(pThPool->m_qWait[0]);pThPool->m_qWait.erase(pThPool->m_qWait.begin());LeaveCriticalSection(&(pThPool->m_cs));PostThreadMessage(dwCurId,WM_THREADSTART,(WPARAM)vObj[vObj.size()-1],0);while(1){MSG msgtemp;PeekMessage(&msgtemp,0,WM_THREADSTART,WM_THREADPOOLIDIL,PM_NOREMOVE);if(msgtemp.message!=WM_THREADSTART){PeekMessage(&msgtemp,0,WM_THREADSTART,WM_THREADPOOLIDIL,PM_REMOVE);PostThreadMessage(dwCurId,msgtemp.message,msgtemp.wParam,msgtemp.lParam);}else{break;}}}else{break;}nCount--;}}}}return 0;}DWORD CThreadPool::GetRunThreadCount(){return m_qRun.size();}CThreadPool::spThread CThreadPool::GetRunThreadItem(int nIndex){return m_qRun[nIndex];}DWORD CThreadPool::GetWaitThreadCount(){return m_qWait.size();}CThreadPool::spThread CThreadPool::GetWaitThreadItem(int nIndex){return m_qWait[nIndex];}DWORD WINAPI t(LPVOID l){cout<<GetCurrentThreadId()<<endl;return 0;}DWORD WINAPI t1(LPVOID l){cout<<"!!!"<<endl;return 0;}void call(UINT m,CThreadPool::spThread sp){if(m==WM_THREADSTART){//cout<<1<<endl;}}main(){CThreadPool c;c.Init(0,5);DWORD i=1000;while(i--){c.AddTask(t,0,0);}c.AddTask(t1,0,1);getchar();}
谈谈实现原理，我在这个类的内部定义了两个vector，一个是储存当前运行的线程，还有一个是储存等待运行的线程，这个由m_nMaxThreadCount决定，当我们init线程池的时候，有一个PeekMessage(&msg,0,WM_USER,WM_USER,PM_NOREMOVE);语句，会强制创建消息队列。然后我们便可以在线程的消息队列中接受消息来控制线程的运行，当idil时，线程池会自动移除当前运行vector里终止的线程，从等待vector里移入待运行的线程，并提高WM_THREADSTART消息的优先级，确保新线程能即使创建。
本文有不足之处，还望大家多多指正。