Close #20105: set __traceback__ when chaining exceptions in C
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
index 8658a58..d4065e0 100644
--- a/Doc/c-api/exceptions.rst
+++ b/Doc/c-api/exceptions.rst
@@ -90,6 +90,16 @@
    the class in that case.  If the values are already normalized, nothing happens.
    The delayed normalization is implemented to improve performance.
 
+   .. note::
+
+      This function *does not* implicitly set the ``__traceback__``
+      attribute on the exception value. If setting the traceback
+      appropriately is desired, the following additional snippet is needed::
+
+         if (tb != NULL) {
+           PyException_SetTraceback(val, tb);
+         }
+
 
 .. c:function:: void PyErr_Clear()