diff -r d9c98730e2e8 -r eada2669b41f Doc/library/functions.rst
--- a/Doc/library/functions.rst	Sat Jul 07 13:34:50 2012 +1000
+++ b/Doc/library/functions.rst	Sat Jul 07 12:57:23 2012 +0200
@@ -546,6 +546,12 @@
    ``x.foobar``.  If the named attribute does not exist, *default* is returned if
    provided, otherwise :exc:`AttributeError` is raised.
 
+   .. note::
+
+      Since :ref:`private name mangling <private-name-mangling>` happens at
+      compilation time, private attributes are not found by :func:`getattr` unless
+      the mangled name is used.
+
 
 .. function:: globals()
 
@@ -1181,6 +1187,11 @@
    object allows it.  For example, ``setattr(x, 'foobar', 123)`` is equivalent to
    ``x.foobar = 123``.
 
+   .. note::
+
+      Since :ref:`private name mangling <private-name-mangling>` only happens at
+      compilation time, private attributes set by :func:`setattr` are not mangled.
+
 
 .. function:: slice([start,] stop[, step])
 
diff -r d9c98730e2e8 -r eada2669b41f Doc/reference/expressions.rst
--- a/Doc/reference/expressions.rst	Sat Jul 07 13:34:50 2012 +1000
+++ b/Doc/reference/expressions.rst	Sat Jul 07 12:57:23 2012 +0200
@@ -80,6 +80,8 @@
    pair: name; mangling
    pair: private; names
 
+.. _private-name-mangling:
+
 **Private name mangling:** When an identifier that textually occurs in a class
 definition begins with two or more underscore characters and does not end in two
 or more underscores, it is considered a :dfn:`private name` of that class.