1# /* **************************************************************************
2# * *
3# * (C) Copyright Paul Mensonides 2003.
4# * (C) Copyright Edward Diener 2014.
5# * Distributed under the Boost Software License, Version 1.0. (See
6# * accompanying file LICENSE_1_0.txt or copy at
7# * http://www.boost.org/LICENSE_1_0.txt)
8# * *
9# ************************************************************************** */
10#
11# /* See http://www.boost.org for most recent version. */
12#
13# ifndef BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_HPP
14# define BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_HPP
15#
16# include <boost/preprocessor/config/config.hpp>
17#
18# if BOOST_PP_VARIADICS
19#
20# include <boost/preprocessor/facilities/is_empty_variadic.hpp>
21#
22# else
23#
24# if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC() && ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC()
25# include <boost/preprocessor/tuple/elem.hpp>
26# include <boost/preprocessor/facilities/identity.hpp>
27# else
28# include <boost/preprocessor/cat.hpp>
29# include <boost/preprocessor/detail/split.hpp>
30# endif
31#
32# /* BOOST_PP_IS_EMPTY */
33#
34# if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC() && ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC()
35# define BOOST_PP_IS_EMPTY(x) BOOST_PP_IS_EMPTY_I(x BOOST_PP_IS_EMPTY_HELPER)
36# define BOOST_PP_IS_EMPTY_I(contents) BOOST_PP_TUPLE_ELEM(2, 1, (BOOST_PP_IS_EMPTY_DEF_ ## contents()))
37# define BOOST_PP_IS_EMPTY_DEF_BOOST_PP_IS_EMPTY_HELPER 1, BOOST_PP_IDENTITY(1)
38# define BOOST_PP_IS_EMPTY_HELPER() , 0
39# else
40# if BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC()
41# define BOOST_PP_IS_EMPTY(x) BOOST_PP_IS_EMPTY_I(BOOST_PP_IS_EMPTY_HELPER x ())
42# define BOOST_PP_IS_EMPTY_I(test) BOOST_PP_IS_EMPTY_II(BOOST_PP_SPLIT(0, BOOST_PP_CAT(BOOST_PP_IS_EMPTY_DEF_, test)))
43# define BOOST_PP_IS_EMPTY_II(id) id
44# else
45# define BOOST_PP_IS_EMPTY(x) BOOST_PP_IS_EMPTY_I((BOOST_PP_IS_EMPTY_HELPER x ()))
46# define BOOST_PP_IS_EMPTY_I(par) BOOST_PP_IS_EMPTY_II ## par
47# define BOOST_PP_IS_EMPTY_II(test) BOOST_PP_SPLIT(0, BOOST_PP_CAT(BOOST_PP_IS_EMPTY_DEF_, test))
48# endif
49# define BOOST_PP_IS_EMPTY_HELPER() 1
50# define BOOST_PP_IS_EMPTY_DEF_1 1, BOOST_PP_NIL
51# define BOOST_PP_IS_EMPTY_DEF_BOOST_PP_IS_EMPTY_HELPER 0, BOOST_PP_NIL
52# endif
53#
54# endif /* BOOST_PP_VARIADICS */
55#
56# endif /* BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_HPP */
57

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