+\begin{verbatim}
+int wxCALLBACK wxListCompareFunction(long item1, long item2, long sortData)
+\end{verbatim}
+
+It is called each time when the two items must be compared and should return 0
+if the items are equal, negative value if the first item is less than the
+second one and positive value if the first one is greater than the second one
+(the same convention as used by {\tt qsort(3)}).
+
+\wxheading{Parameters}