diff -r 064f6baeb6bd Doc/library/functions.rst
--- a/Doc/library/functions.rst	Wed Sep 24 09:08:12 2014 +0200
+++ b/Doc/library/functions.rst	Thu Sep 25 09:00:34 2014 +0200
@@ -1098,6 +1098,10 @@ are always available.  They are listed h
    is buffered is usually determined by *file*, but if the  *flush* keyword
    argument is true, the stream is forcibly flushed.
 
+   :func:`print` is a convenience function.  Since it converts all arguments to
+   strings, it cannot be used to write to *file* objects in binary mode that
+   expect bytes objects; use ``file.write(...)`` for that purpose.
+
    .. versionchanged:: 3.3
       Added the *flush* keyword argument.