m_lpCmdLine Corresponds to the lpCmdLine parameter passed by Windows to WinMain. Points to a null-terminated string that specifies the command line for the application. Use m_lpCmdLine to access any command-line arguments the user entered when the application was started. m_lpCmdLine is a public variable of type LPTSTR.
if (m_lpCmdLine == _T('\0'))
// Create a new (empty) document.
// Open a file passed as the first command line parameter.