C / C++ / MFC

void CTest03Dlg::OnButton1() 
{
	CString	s("Hello test....\n\n");
	
	std::ofstream	f("MyText.txt", std::ios::app | std::ios::out);
	f.write(s.operator LPCTSTR(), s.GetLength());
	f.close();
}

void CTest03Dlg::OnButton2() 
{
	WinExec("Notepad MyText.txt", SW_SHOW);	
}

//Somewhere in code.
...
    CString *pStr = new CString();
    *pStr = "Set String Here!";
 
    //NOTE: Receiver of this message must delete pointer!!!
    pMyView->PostMessage(WM_MY_MSG, 0, (LPARAM)pStr);
...

LRESULT CMyView::OnHandleMyMsg(WPARAM wParam, LPARAM lParam)
{
    CString *pStr = (CString *)lParam;
    if(pStr)
    {
        //Do something with the string...
 
        //We must delete it when done!!!
        delete pStr;
    }
    return 0;
}

void CMyView::OnDestroy() 
{
    //Look for any WM_MY_MSG left in the queue. These have
    // pointers to allocated memory that must be freed or we will
    // have leaks!
    MSG msg;
    while(::PeekMessage(&msg, (HWND)NULL, WM_MY_MSG, WM_MY_MSG, PM_REMOVE))
    {
        CString *pStr = (CString *)msg.lParam;
        if(pStr)
            delete pStr;
    }
    CView::OnDestroy();
}