diff --git a/v2/example/pch/include/pch.hpp b/v2/example/pch/include/pch.hpp
index 22df8443f..8f05cc43d 100644
--- a/v2/example/pch/include/pch.hpp
+++ b/v2/example/pch/include/pch.hpp
@@ -5,7 +5,15 @@
    http://www.boost.org/LICENSE_1_0.txt)
 */
 
+#ifdef BOOST_BUILD_PCH_ENABLED
+
+#ifdef FOO2
+int bar();
+#endif
+
 class TestClass {
 public:
     TestClass(int, int) {}
 };
+
+#endif