#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/debug/assert.hpp>
#include <boost/preprocessor/logical/bitnor.hpp>
#include <boost/preprocessor/logical/compl.hpp>

// The is BOOST_PP_IS_NULLARY macro is not part of
// the public interface of the library because it
// doesn't work on Borland preprocessors.  It is
// only used here to illustrate assertions.  In
// effect, it detects whether an argument is empty
// parenthesis or some text.

#include <boost/preprocessor/detail/is_nullary.hpp>

#define IS_EDISON_DESIGN_GROUP() \
   BOOST_PP_COMPL( \
      BOOST_PP_IS_NULLARY( \
         BOOST_PP_CAT(IS_EDG_CHECK, __EDG_VERSION) \
      ) \
   ) \
   /**/
#define IS_EDG_CHECK__EDG_VERSION ()

#define IS_METROWERKS() \
   BOOST_PP_COMPL( \
      BOOST_PP_IS_NULLARY( \
         BOOST_PP_CAT(IS_MWERKS_CHECK, __MWERKS__) \
      ) \
   ) \
   /**/
#define IS_MWERKS_CHECK__MWERKS__ ()

#define IS_MICROSOFT() \
   BOOST_PP_BITNOR( \
      IS_MICROSOFT_ROOT(), \
      IS_EDISON_DESIGN_GROUP() \
   ) \
   /**/
#define IS_MICROSOFT_ROOT() \
   BOOST_PP_IS_NULLARY( \
      BOOST_PP_CAT(IS_MSVC_CHECK, _MSC_VER) \
   ) \
   /**/
#define IS_MSVC_CHECK_MS_VER ()

// this macro doesn't work on EDG...
// (this is just an example)

#define MACRO(n) \
   BOOST_PP_CAT( \
      MACRO_, \
      IS_EDISON_DESIGN_GROUP() \
   )(n) \
   /**/

#define MACRO_1(n) \
   BOOST_PP_ASSERT(0) \
   "Edison Design Group is not supported" \
   /**/

#define MACRO_0(n) normal mode: n

MACRO(10)

Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at www.boost.org/LICENSE_1_0.txt)