diff --git a/Doc/library/select.rst b/Doc/library/select.rst
--- a/Doc/library/select.rst
+++ b/Doc/library/select.rst
@@ -38,12 +38,20 @@
    for I/O events; see section :ref:`poll-objects` below for the methods supported
    by polling objects.
 
+   .. note:: MacOSX support for poll is limited, the poll function
+      only works pipes, sockets, files and the slave ends of ttys. It will not
+      work with other types of files, such as special files.
+
 
 .. function:: kqueue()
 
    (Only supported on BSD.)  Returns a kernel queue object; see section
    :ref:`kqueue-objects` below for the methods supported by kqueue objects.
 
+   .. note:: MacOSX support for kqueue is limited, the kqueue function
+      only works pipes, sockets, files and the slave ends of ttys. It will not
+      work with other types of files, such as special files.
+
 
 .. function:: kevent(ident, filter=KQ_FILTER_READ, flags=KQ_EV_ADD, fflags=0, data=0, udata=0)