Issue 2235: document PyObject_HashNotImplemented
diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index 7bb845a..883d095 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -269,6 +269,16 @@
This is the equivalent of the Python expression ``hash(o)``.
+.. cfunction:: long PyObject_HashNotImplemented(PyObject *o)
+
+ Set a TypeError indicating that ``type(o)`` is not hashable and return ``-1``.
+ This function receives special treatment when stored in a ``tp_hash`` slot,
+ allowing a type to explicit indicate to the interpreter that it is not
+ hashable.
+
+ .. versionadded:: 2.6
+
+
.. cfunction:: int PyObject_IsTrue(PyObject *o)
Returns ``1`` if the object *o* is considered to be true, and ``0`` otherwise.