diff -r f48f302f54aa Doc/library/selectors.rst
--- a/Doc/library/selectors.rst	Sun Dec 01 11:04:17 2013 +0100
+++ b/Doc/library/selectors.rst	Sun Dec 01 13:15:05 2013 +0100
@@ -150,6 +150,11 @@
       object.
       *events* is a bitmask of events ready on this file object.
 
+      .. note::
+          This method can return before any file object becomes ready or the
+          timeout has elapsed if the current process receives a signal: in this
+          case, an empty list will be returned.
+
    .. method:: close()
 
       Close the selector.