ceph/src/boost/libs/mp11/test/construct_from_tuple_cx.cpp

   1
   2 //  Copyright 2015 Peter Dimov.
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 //
   6 // See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt
   8
   9 #include <boost/mp11/tuple.hpp>
  10 #include <boost/config.hpp>
  11
  12 // Technically std::tuple isn't constexpr enabled in C++11, but it works with libstdc++
  13
  14 #if defined( BOOST_NO_CXX11_CONSTEXPR ) || ( defined( _LIBCPP_VERSION ) && __cplusplus < 201400L )
  15
  16 int main() {}
  17
  18 #else
  19
  20 #include <tuple>
  21 #include <array>
  22 #include <utility>
  23
  24 struct T1
  25 {
  26     int x, y, z;
  27
  28     constexpr T1( int x = 0, int y = 0, int z = 0 ): x(x), y(y), z(z) {}
  29 };
  30
  31 int main()
  32 {
  33     using boost::mp11::construct_from_tuple;
  34
  35     {
  36         constexpr std::tuple<int, short, char> tp{ 1, 2, 3 };
  37
  38         constexpr auto r = construct_from_tuple<T1>( tp );
  39
  40         static_assert( r.x == 1, "r.x == 1" );
  41         static_assert( r.y == 2, "r.y == 2" );
  42         static_assert( r.z == 3, "r.z == 3" );
  43     }
  44
  45     {
  46         constexpr std::pair<short, char> tp{ 1, 2 };
  47
  48         constexpr auto r = construct_from_tuple<T1>( tp );
  49
  50         static_assert( r.x == 1, "r.x == 1" );
  51         static_assert( r.y == 2, "r.y == 2" );
  52         static_assert( r.z == 0, "r.z == 0" );
  53     }
  54
  55     {
  56         constexpr std::array<short, 3> tp{{ 1, 2, 3 }};
  57
  58         constexpr auto r = construct_from_tuple<T1>( tp );
  59
  60         static_assert( r.x == 1, "r.x == 1" );
  61         static_assert( r.y == 2, "r.y == 2" );
  62         static_assert( r.z == 3, "r.z == 3" );
  63     }
  64
  65 #if defined( __clang_major__ ) && __clang_major__ == 3 && __clang_minor__ < 9
  66 // "error: default initialization of an object of const type 'const std::tuple<>' without a user-provided default constructor"
  67 #else
  68
  69     {
  70         constexpr std::tuple<> tp;
  71
  72         constexpr auto r = construct_from_tuple<T1>( tp );
  73
  74         static_assert( r.x == 0, "r.x == 0" );
  75         static_assert( r.y == 0, "r.y == 0" );
  76         static_assert( r.z == 0, "r.z == 0" );
  77     }
  78
  79 #endif
  80 }
  81
  82 #endif