1# /* **************************************************************************
2# * *
3# * (C) Copyright Edward Diener 2014,2019.
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# if defined(__cplusplus) && __cplusplus > 201703L
41# include <boost/preprocessor/variadic/has_opt.hpp>
42#define BOOST_PP_IS_EMPTY(...) \
43 BOOST_PP_DETAIL_IS_EMPTY_IIF \
44 ( \
45 BOOST_PP_VARIADIC_HAS_OPT() \
46 ) \
47 ( \
48 BOOST_PP_IS_EMPTY_OPT, \
49 BOOST_PP_IS_EMPTY_NO_OPT \
50 ) \
51 (__VA_ARGS__) \
52/**/
53#define BOOST_PP_IS_EMPTY_FUNCTION2(...) \
54 __VA_OPT__(0,) 1 \
55/**/
56#define BOOST_PP_IS_EMPTY_FUNCTION(...) \
57 BOOST_PP_IS_EMPTY_FUNCTION2(__VA_ARGS__) \
58/**/
59#define BOOST_PP_IS_EMPTY_OPT(...) \
60 BOOST_PP_VARIADIC_HAS_OPT_ELEM0(BOOST_PP_IS_EMPTY_FUNCTION(__VA_ARGS__),) \
61/**/
62# else
63#define BOOST_PP_IS_EMPTY(...) \
64 BOOST_PP_IS_EMPTY_NO_OPT(__VA_ARGS__) \
65/**/
66# endif /* defined(__cplusplus) && __cplusplus > 201703L */
67#define BOOST_PP_IS_EMPTY_NO_OPT(...) \
68 BOOST_PP_DETAIL_IS_EMPTY_IIF \
69 ( \
70 BOOST_PP_IS_BEGIN_PARENS \
71 ( \
72 __VA_ARGS__ \
73 ) \
74 ) \
75 ( \
76 BOOST_PP_IS_EMPTY_ZERO, \
77 BOOST_PP_DETAIL_IS_EMPTY_PROCESS \
78 ) \
79 (__VA_ARGS__) \
80/**/
81#define BOOST_PP_IS_EMPTY_ZERO(...) 0
82# endif /* BOOST_PP_VARIADICS_MSVC && _MSC_VER <= 1400 */
83# endif /* BOOST_PP_VARIADICS */
84# endif /* BOOST_PREPROCESSOR_FACILITIES_IS_EMPTY_VARIADIC_HPP */
85

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