1# /* **************************************************************************
2# * *
3# * (C) Copyright Edward Diener 2014.
4# * Distributed under the Boost Software License, Version 1.0. (See
5# * accompanying file LICENSE_1_0.txt or copy at
6# * http://www.boost.org/LICENSE_1_0.txt)
7# * *
8# ************************************************************************** */
9#
10# /* See http://www.boost.org for most recent version. */
11#
12# ifndef BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP
13# define BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP
14#
15# include <boost/preprocessor/config/config.hpp>
16#
17# if BOOST_PP_VARIADICS
18#
19# include <boost/preprocessor/punctuation/is_begin_parens.hpp>
20# include <boost/preprocessor/facilities/detail/is_empty.hpp>
21#
22#if BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400
23#
24#define BOOST_PP_IS_EMPTY(param) \
25 BOOST_PP_DETAIL_IS_EMPTY_IIF \
26 ( \
27 BOOST_PP_IS_BEGIN_PARENS \
28 ( \
29 param \
30 ) \
31 ) \
32 ( \
33 BOOST_PP_IS_EMPTY_ZERO, \
34 BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
35 ) \
36 (param) \
37/**/
38#define BOOST_PP_IS_EMPTY_ZERO(param) 0
39# else
40#define BOOST_PP_IS_EMPTY(...) \
41 BOOST_PP_DETAIL_IS_EMPTY_IIF \
42 ( \
43 BOOST_PP_IS_BEGIN_PARENS \
44 ( \
45 __VA_ARGS__ \
46 ) \
47 ) \
48 ( \
49 BOOST_PP_IS_EMPTY_ZERO, \
50 BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
51 ) \
52 (__VA_ARGS__) \
53/**/
54#define BOOST_PP_IS_EMPTY_ZERO(...) 0
55# endif /* BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400 */
56# endif /* BOOST_PP_VARIADICS */
57# endif /* BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP */
58

source code of boost/boost/preprocessor/facilities/is_empty_variadic.hpp