The BOOST_PP_IS_ITERATING macro is defined when a file-iteration is in progress.


#if !defined(BOOST_PP_IS_ITERATING) // ...


If a file-iteration is in progress, this macro is defined as 1.  This means that the following will also work:
This macro is defined to guard a file from infinite inclusion.

Copyright Housemarque Oy 2002
Copyright Paul Mensonides 2002

Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at