temporarily with the window as an argument;
\item events from sliders and scrollbars can be handled more flexibly;
\item the handling of window close events has been changed in line with the new
-event system, but backward {\bf OnClose} compatibility has been retained;
+event system;
\item the concept of {\it validator} has been added to allow much easier coding of
the relationship between controls and application data;
\item the documentation has been revised, with more cross-referencing.
\begin{verbatim}
ftp://www.remstar.com/pub/wxwin
- http://wxwin.home.ml.org
+ http://web.ukonline.co.uk/julian.smart/wxwin
\end{verbatim}
\section{Acknowledgments}
wxWindows does not use templates since it is a notoriously unportable feature.
+\subsection{RTTI}
+
+wxWindows does not use run-time type information since wxWindows provides
+its own run-time type information system, implemented using macros.
+
+\subsection{Type of NULL}
+
+Some compilers (e.g. the native IRIX cc) define NULL to be 0L so that
+no conversion to pointers is allowed. Because of that, all these
+occurences of NULL in the GTK port use an explicit conversion such
+as
+
+{\small
+\begin{verbatim}
+ wxWindow *my_window = (wxWindow*) NULL;
+\end{verbatim}
+}
+
+It is recommended to adhere to this in all code using wxWindows as
+this make the code (a bit) more portable.
+
\subsection{Precompiled headers}
Some compilers, such as Borland C++ and Microsoft C++, support