1/*=============================================================================
2 Copyright (c) 2014 Eric Niebler
3 Copyright (c) 2014,2015,2018 Kohei Takahashi
4
5 Distributed under the Boost Software License, Version 1.0. (See accompanying
6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7==============================================================================*/
8#if !defined(FUSION_SUPPORT_CONFIG_01092014_1718)
9#define FUSION_SUPPORT_CONFIG_01092014_1718
10
11#include <boost/config.hpp>
12#include <boost/detail/workaround.hpp>
13#include <utility>
14
15#ifndef BOOST_FUSION_GPU_ENABLED
16#define BOOST_FUSION_GPU_ENABLED BOOST_GPU_ENABLED
17#endif
18
19// Enclose with inline namespace because unqualified lookup of GCC < 4.5 is broken.
20//
21// namespace detail {
22// struct foo;
23// struct X { };
24// }
25//
26// template <typename T> void foo(T) { }
27//
28// int main()
29// {
30// foo(detail::X());
31// // prog.cc: In function 'int main()':
32// // prog.cc:2: error: 'struct detail::foo' is not a function,
33// // prog.cc:6: error: conflict with 'template<class T> void foo(T)'
34// // prog.cc:10: error: in call to 'foo'
35// }
36namespace boost { namespace fusion { namespace detail
37{
38 namespace barrier { }
39 using namespace barrier;
40}}}
41#define BOOST_FUSION_BARRIER_BEGIN namespace barrier {
42#define BOOST_FUSION_BARRIER_END }
43
44
45#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1900))
46// All of rvalue-reference ready MSVC don't perform implicit conversion from
47// fundamental type to rvalue-reference of another fundamental type [1].
48//
49// Following example doesn't compile
50//
51// int i;
52// long &&l = i; // sigh..., std::forward<long&&>(i) also fail.
53//
54// however, following one will work.
55//
56// int i;
57// long &&l = static_cast<long &&>(i);
58//
59// OK, now can we replace all usage of std::forward to static_cast? -- I say NO!
60// All of rvalue-reference ready Clang doesn't compile above static_cast usage [2], sigh...
61//
62// References:
63// 1. https://connect.microsoft.com/VisualStudio/feedback/details/1037806/implicit-conversion-doesnt-perform-for-fund
64// 2. http://llvm.org/bugs/show_bug.cgi?id=19917
65//
66// Tentatively, we use static_cast to forward if run under MSVC.
67# define BOOST_FUSION_FWD_ELEM(type, value) static_cast<type&&>(value)
68#else
69# define BOOST_FUSION_FWD_ELEM(type, value) std::forward<type>(value)
70#endif
71
72
73// Workaround for LWG 2408: C++17 SFINAE-friendly std::iterator_traits.
74// http://cplusplus.github.io/LWG/lwg-defects.html#2408
75//
76// - GCC 4.5 enables the feature under C++11.
77// https://gcc.gnu.org/ml/gcc-patches/2014-11/msg01105.html
78//
79// - MSVC 10.0 implements iterator intrinsics; MSVC 13.0 implements LWG2408.
80#if (defined(BOOST_LIBSTDCXX_VERSION) && (BOOST_LIBSTDCXX_VERSION < 40500) && \
81 defined(BOOST_LIBSTDCXX11)) || \
82 (defined(BOOST_MSVC) && (1600 <= BOOST_MSVC && BOOST_MSVC < 1900))
83# define BOOST_FUSION_WORKAROUND_FOR_LWG_2408
84namespace std
85{
86 template <typename>
87 struct iterator_traits;
88}
89#endif
90
91
92// Workaround for older GCC that doesn't accept `this` in constexpr.
93#if BOOST_WORKAROUND(BOOST_GCC, < 40700)
94#define BOOST_FUSION_CONSTEXPR_THIS
95#else
96#define BOOST_FUSION_CONSTEXPR_THIS BOOST_CONSTEXPR
97#endif
98
99
100// Workaround for compilers not implementing N3031 (DR743 and DR950).
101#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1913)) || \
102 BOOST_WORKAROUND(BOOST_GCC, < 40700) || \
103 defined(BOOST_CLANG) && (__clang_major__ == 3 && __clang_minor__ == 0)
104# if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
105namespace boost { namespace fusion { namespace detail
106{
107 template <typename T>
108 using type_alias_t = T;
109}}}
110# define BOOST_FUSION_DECLTYPE_N3031(parenthesized_expr) \
111 boost::fusion::detail::type_alias_t<decltype parenthesized_expr>
112# else
113# include <boost/mpl/identity.hpp>
114# define BOOST_FUSION_DECLTYPE_N3031(parenthesized_expr) \
115 boost::mpl::identity<decltype parenthesized_expr>::type
116# endif
117#else
118# define BOOST_FUSION_DECLTYPE_N3031(parenthesized_expr) \
119 decltype parenthesized_expr
120#endif
121
122
123// Workaround for GCC 4.6 that rejects defaulted function with noexcept.
124#if BOOST_WORKAROUND(BOOST_GCC, / 100 == 406)
125# define BOOST_FUSION_NOEXCEPT_ON_DEFAULTED
126#else
127# define BOOST_FUSION_NOEXCEPT_ON_DEFAULTED BOOST_NOEXCEPT
128#endif
129
130#endif
131

source code of include/boost/fusion/support/config.hpp