控制程序运行不超过指定个数实例的一种方法

// CSemaphoreApp initializationBOOL CSemaphoreApp::InitInstance(){AfxEnableControlContainer();// Standard initialization// If you are not using these features and wish to reduce the size//  of your final executable, you should remove from the following//  the specific initialization routines you do not need.#ifdef _AFXDLLEnable3dControls();// Call this when using MFC in a shared DLL#elseEnable3dControlsStatic();// Call this when linking to MFC statically#endifDWORD wd;HANDLE handle = CreateSemaphore(NULL,2,2,"ZE_IN_NUM");if(GetLastError() == ERROR_ALREADY_EXISTS){handle = OpenSemaphore(SEMAPHORE_MODIFY_STATE | SYNCHRONIZE,FALSE,"ZE_IN_NUM");if(handle != NULL){wd = WaitForSingleObject(handle,1000) ;if(wd == WAIT_OBJECT_0){//AfxMessageBox("启动实例");}else if(wd == WAIT_TIMEOUT){//退出主线程return FALSE;}else{//退出主线程return FALSE;}}else{//退出主线程return FALSE;}}CSemaphoreDlg dlg;m_pMainWnd = &dlg;int nResponse = dlg.DoModal();if (nResponse == IDOK){// TODO: Place code here to handle when the dialog is//  dismissed with OK}else if (nResponse == IDCANCEL){// TODO: Place code here to handle when the dialog is//  dismissed with Cancel}//释放信号long nCount = 0;ReleaseSemaphore(handle,1,&nCount);// Since the dialog has been closed, return FALSE so that we exit the//  application, rather than start the application's message pump.return FALSE;}