+\subsection{Feature tests}\label{featuretests}
+
+Some library features may not be always available even if they were selected by
+the user. To make it possible to check if this is the case, the library
+predefines the symbols in the form \texttt{wxHAS\_FEATURE}. Unlike
+\texttt{wxUSE\_FEATURE} symbols which are defined by the library user (directly
+in \texttt{setup.h} or by running configure script) and which must be always
+defined as either $0$ or $1$, the \texttt{wxHAS} symbols are only defined if
+the corresponding feature is available and not defined at all otherwise.
+
+Currently the following symbols exist:
+\begin{twocollist}\itemsep=0pt
+\twocolitem{wxHAS\_LARGE\_FILES}{Defined if \helpref{wxFile}{wxfile} supports
+files more than 4GB in size.}
+\twocolitem{wxHAS\_LARGE\_FFILES}{Defined if \helpref{wxFFile}{wxffile}
+supports files more than 4GB in size.}
+\twocolitem{wxHAS\_POWER\_EVENTS}{Defined if
+\helpref{wxPowerEvent}{wxpowerevent} are ever generated on the current platform.}
+\twocolitem{wxHAS\_RADIO\_MENU\_ITEMS}{Defined if the current port supports
+\helpref{radio menu items}{wxmenuappendradioitem}.}
+\twocolitem{wxHAS\_RAW\_KEY\_CODES}{Defined if
+\helpref{raw key codes}{wxkeyeventgetrawkeycode} are supported.}
+\twocolitem{wxHAS\_REGEX\_ADVANCED}{Defined if advanced syntax is available in
+\helpref{wxRegEx}{wxregex}.}
+\twocolitem{wxHAS\_TASK\_BAR\_ICON}{Defined if
+\helpref{wxTaskBarIcon}{wxtaskbaricon} is available on the current platform.}
+\end{twocollist}
+
+