ceph/src/boost/libs/mp11/test/tuple_for_each_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(_MSC_VER) && !defined( __GLIBCXX__ ) && __cplusplus < 201400L )
  20
  21 int main() {}
  22
  23 #else
  24
  25 #include <tuple>
  26 #include <type_traits>
  27
  28 struct assert_is_integral
  29 {
  30     template<class T> constexpr bool operator()( T ) const
  31     {
  32         static_assert( std::is_integral<T>::value, "T must be an integral type" );
  33         return true;
  34     }
  35 };
  36
  37 int main()
  38 {
  39     {
  40         constexpr std::tuple<int, short, char> tp{ 1, 2, 3 };
  41         constexpr auto r = boost::mp11::tuple_for_each( tp, assert_is_integral() );
  42         (void)r;
  43     }
  44
  45 #if defined( __clang_major__ ) && __clang_major__ == 3 && __clang_minor__ < 9
  46 // "error: default initialization of an object of const type 'const std::tuple<>' without a user-provided default constructor"
  47 #else
  48
  49     {
  50         constexpr std::tuple<> tp;
  51         constexpr auto r = boost::mp11::tuple_for_each( tp, 11 );
  52         static_assert( r == 11, "r == 11" );
  53     }
  54
  55 #endif
  56 }
  57
  58 #endif