使应用程序只能运行一个实例

BOOL CSingleDocApp::InitInstance()
{

 HANDLE hSep = ::CreateSemaphore(NULL,1,1,m_strAppName);

 if(GetLastError() == ERROR_ALREADY_EXISTS)
 {
        CloseHandle(hSep);

  HWND hWnd = ::GetWindow(::GetDesktopWindow(),GW_CHILD);
  
  while(hWnd)
  {
            if(GetProp(hWnd,m_strAppName))
   {
                if(::IsIconic(hWnd))
     ::ShowWindow(hWnd,SW_RESTORE);

    ::SetForegroundWindow(hWnd);

    return FALSE;
   }

   hWnd = ::GetWindow(hWnd,GW_HWNDNEXT);
  }

  return FALSE;
 }
 AfxEnableControlContainer();

......

}

 

int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{

     // .....

    ::SetProp(m_hWnd,theApp.m_strAppName,(HANDLE)1);

    return 0;
}

 

void CMainFrame::OnDestroy()
{
 CFrameWnd::OnDestroy();
 
 // TODO: Add your message handler code here
 RemoveProp(m_hWnd,theApp.m_strAppName);
}