The module is optional. It is supported on Windows, Linux, SGI
IRIX, Solaris 2.x, as well as on systems that have a \POSIX{} thread
-(a.k.a. ``pthread'') implementation.
+(a.k.a. ``pthread'') implementation. For systems lacking the \module{thread}
+module, the \refmodule{dummy_thread} module is available. It duplicates this
+module's interface and can be used as a drop-in replacement.
\index{pthreads}
\indexii{threads}{\POSIX}
This module constructs higher-level threading interfaces on top of the
lower level \refmodule{thread} module.
+The \refmodule{dummy_threading} module is provided for situations where
+\module{threading} cannot be used because \module{thread} is missing.
+
This module is safe for use with \samp{from threading import *}. It
defines the following functions and objects: