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
  10 #if defined(_MSC_VER)
  11 #pragma warning( disable: 4244 ) // 'initializing': conversion from 'int' to 'char', possible loss of data
  12 #endif
  13
  14 #include <boost/mp11/tuple.hpp>
  15 #include <boost/mp11/detail/config.hpp>
  16
  17 // Technically std::tuple isn't constexpr enabled in C++11, but it works with libstdc++
  18
  19 #if defined( BOOST_MP11_NO_CONSTEXPR ) || ( !defined( __GLIBCXX__ ) && __cplusplus < 201400L )
  20
  21 int main() {}
  22
  23 #else
  24
  25 #include <tuple>
  26 #include <array>
  27 #include <utility>
  28
  29 struct T1
  30 {
  31     int x, y, z;
  32
  33     constexpr T1( int x = 0, int y = 0, int z = 0 ): x(x), y(y), z(z) {}
  34 };
  35
  36 int main()
  37 {
  38     using boost::mp11::construct_from_tuple;
  39
  40     {
  41         constexpr std::tuple<int, short, char> tp{ 1, 2, 3 };
  42
  43         constexpr auto r = construct_from_tuple<T1>( tp );
  44
  45         static_assert( r.x == 1, "r.x == 1" );
  46         static_assert( r.y == 2, "r.y == 2" );
  47         static_assert( r.z == 3, "r.z == 3" );
  48     }
  49
  50     {
  51         constexpr std::pair<short, char> tp{ 1, 2 };
  52
  53         constexpr auto r = construct_from_tuple<T1>( tp );
  54
  55         static_assert( r.x == 1, "r.x == 1" );
  56         static_assert( r.y == 2, "r.y == 2" );
  57         static_assert( r.z == 0, "r.z == 0" );
  58     }
  59
  60     {
  61         constexpr std::array<short, 3> tp{{ 1, 2, 3 }};
  62
  63         constexpr auto r = construct_from_tuple<T1>( tp );
  64
  65         static_assert( r.x == 1, "r.x == 1" );
  66         static_assert( r.y == 2, "r.y == 2" );
  67         static_assert( r.z == 3, "r.z == 3" );
  68     }
  69
  70 #if defined( __clang_major__ ) && __clang_major__ == 3 && __clang_minor__ < 9
  71 // "error: default initialization of an object of const type 'const std::tuple<>' without a user-provided default constructor"
  72 #else
  73
  74     {
  75         constexpr std::tuple<> tp;
  76
  77         constexpr auto r = construct_from_tuple<T1>( tp );
  78
  79         static_assert( r.x == 0, "r.x == 0" );
  80         static_assert( r.y == 0, "r.y == 0" );
  81         static_assert( r.z == 0, "r.z == 0" );
  82     }
  83
  84 #endif
  85 }
  86
  87 #endif