ceph/src/boost/boost/fusion/support/config.hpp

   1 /*=============================================================================
   2     Copyright (c) 2014 Eric Niebler
   3     Copyright (c) 2014 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 //      }
  36 namespace 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
  84 namespace 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 #endif