diff --git a/docs/doxygen/Doxyfile_inc b/docs/doxygen/Doxyfile_inc
index 4f823db12b..e408c9d9e1 100644
--- a/docs/doxygen/Doxyfile_inc
+++ b/docs/doxygen/Doxyfile_inc
@@ -223,7 +223,7 @@ FILE_VERSION_FILTER    =
 
 QUIET                  = YES
 WARNINGS               = YES
-WARN_IF_UNDOCUMENTED   = NO
+WARN_IF_UNDOCUMENTED   = YES
 WARN_IF_DOC_ERROR      = YES
 WARN_NO_PARAMDOC       = YES
 WARN_FORMAT            = "$file:$line: $text   "