diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 991093e..739350b 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -910,7 +910,9 @@
    *end*.
 
    The *file* argument must be an object with a ``write(string)`` method; if it
-   is not present or ``None``, :data:`sys.stdout` will be used.
+   is not present or ``None``, :data:`sys.stdout` will be used.   Output buffering
+   is determined by *file*. Use ``file.flush()`` to ensure, for instance,
+   immediate appearance on a screen.
 
    .. note::