C / C++ / MFC

if(SomeMethod(........,nErrCode))
{
    //success
}
else
{
    cout << "error code " << nErrCode;
}

DataSet* MyReadXMLFunc()
{
  DataSet* ds = new DataSet("MyDataSet");
  try
  {
    ds.ReadXml ("C:\\Text.xml");
    ....
  }
  catch (Exception* e)
  {
   // here you must do some cleaning 
   ....
   
   // You can popup a message box
   MessageBox (this, e->Message);
   
   // you can return NULL
   return NULL;
  }
  return ds;
}

// In the caller
DataSet* a = MyReadXMLFunc();
if (a == NULL)
  // something bad happened

  DataSet* ds = new DataSet ("MyDataSet");
  try
  {
    MyReadXMLFunc (ds); //<-- you pass a param here  -->
  }
  catch (Exception* e)
  {
    // it went wrong
  }

 // In the MyReadXMlFunc you do this
void MyReadXMLFunc (DataSet* ds)
{
  try
  {
    ds->ReadXml ("C:\\file.txt");
    .....
  }
  catch (Exception *e)
  {
    // you need to catch an exception only if you want to clean up somethind
    // oterwise the caller will catch it.

    // clean up and rethrow
    throw e;
  }
}

BOOL CScrollbarsView::OnEraseBkgnd(CDC* pDC) 
{
	if (m_ScrollWnd.m_hWnd) // or your control window
		{
		CRect	clip ;
		m_ScrollWnd.GetWindowRect(&clip) ;
		ScreenToClient(&clip) ;
		// exclude the child window from the erase area
		pDC->ExcludeClipRect(clip) ;
		}
	
	return CView::OnEraseBkgnd(pDC);
}