diff --git a/CMakeLists.txt b/CMakeLists.txt
index 20cd5d31..460d3343 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,7 +17,9 @@ if(DOXYGEN_FOUND)
     set(DOXYGEN_USE_MATHJAX YES)
     set(DOCYGEN_GENERATE_TREEVIEW YES)
     set(DOXYGEN_INLINE_SOURCES YES)
+    set(DOXYGEN_CREATE_SUBDIRS YES)
     set(DOXYGEN_STRIP_CODE_COMMENTS NO)
+    set(DOXYGEN_OPTIMIZE_OUTPUT_FOR_C YES)
     if(Doxygen_dot_FOUND)
         set(DOXYGEN_HAVE_DOT YES)
         set(DOXYGEN_CALL_GRAPH YES)