The BOOST_PP_EMPTY macro is a nullary utility macro that expands to nothing.

Usage

BOOST_PP_EMPTY()

Remarks

This macro is helps avoid inefficient macro-expansion.  It is primarily useful as arguments to BOOST_PP_IF or BOOST_PP_IIF.

Requirements

Header:  <boost/preprocessor/facilities/empty.hpp>

Sample Code

#include <boost/preprocessor/control/if.hpp>
#include <boost/preprocessor/facilities/empty.hpp>

#define X() result
#define MACRO(c) BOOST_PP_IF(c, X, BOOST_PP_EMPTY)()

MACRO(0) // expands to nothing
MACRO(1) // expands to result

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 www.boost.org/LICENSE_1_0.txt)