diff --git a/doc/manual-src/en/libaria2.rst b/doc/manual-src/en/libaria2.rst
index f4506518..b98c0d5e 100644
--- a/doc/manual-src/en/libaria2.rst
+++ b/doc/manual-src/en/libaria2.rst
@@ -6,4 +6,6 @@ libaria2: C++ library interface to aria2
 API Reference
 -------------
 
+All enums, types and functions are under ``aria2`` namespace.
+
 .. include:: libaria2api