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Windows allows several copies of the same program to run at the same time.

virtual BOOL InitInstance( );

Return Value

Nonzero if initialization is successful; otherwise 0.


Application initialization is conceptually divided into two sections: one-time application initialization that is done the first time the program runs, and instance initialization that runs each time a copy of the program runs, including the first time. The framework's implementation of WinMain calls this function.

Override InitInstance to initialize each new instance of your application running under Windows. Typically, you override InitInstance to construct your main window object and set the CWinThread::m_pMainWnd data member to point to that window. For more information on overriding this member function, see CWinApp: The Application Class.


MFC applications must be initialized as single threaded apartment (STA). If you call CoInitializeEx in your InitInstance override, specify COINIT_APARTMENTTHREADED (rather than COINIT_MULTITHREADED). For more information, see PRB: MFC Application Stops Responding When You Initialize the Application as a Multithreaded Apartment (828643) at;en-us;828643.


// AppWizard implements the InitInstance overridable function 
// according to options you select.  For example, the multiple document
// interface (MDI) option was chosen for the AppWizard code created
// below. You can add other per-instance initializations to the code
// created by AppWizard.

BOOL CMFCListViewApp::InitInstance()
   // Remainder of function definition omitted.


   // Initialize OLE libraries
   if (!AfxOleInit())
      AfxMessageBox(_T("OleInit failed."));
      return FALSE;

   // 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
   // Change the registry key under which our settings are stored
   // TODO: You should modify this string to be something appropriate
   // such as the name of your company or organization
   SetRegistryKey(_T("Local AppWizard-Generated Applications"));
   LoadStdProfileSettings(4);  // Load standard INI file options (including MRU)
   // Register the application's document templates.  Document templates
   //  serve as the connection between documents, frame windows and views
   CMultiDocTemplate* pDocTemplate;
   pDocTemplate = new CMultiDocTemplate(IDR_MFCListViewTYPE,
      RUNTIME_CLASS(CChildFrame), // custom MDI child frame
   if (!pDocTemplate)
      return FALSE;

   // create main MDI Frame window
   CMainFrame* pMainFrame = new CMainFrame;
   if (!pMainFrame || !pMainFrame->LoadFrame(IDR_MAINFRAME))
      delete pMainFrame;
      return FALSE;
   m_pMainWnd = pMainFrame;
   // call DragAcceptFiles only if there's a suffix
   //  In an MDI app, this should occur immediately after setting m_pMainWnd

   // Parse command line for standard shell commands, DDE, file open
   CCommandLineInfo cmdInfo;

   // Dispatch commands specified on the command line.  Will return FALSE if
   // app was launched with /RegServer, /Register, /Unregserver or /Unregister.
   if (!ProcessShellCommand(cmdInfo))
      return FALSE;
   // The main window has been initialized, so show and update it

   return TRUE;


Header: afxwin.h

See Also


CWinApp Class

Hierarchy Chart

Other Resources

CWinApp Members