support for overriding virtual functions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2e80bd0..96bb795 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,6 +61,7 @@
   example/example9.cpp
   example/example10.cpp
   example/example11.cpp
+  example/example12.cpp
 )
 
 set_target_properties(example PROPERTIES PREFIX "")