libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element.cc

   1 // { dg-do compile { target c++11 } }
   2 //
   3 // Copyright (C) 2011-2025 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10 //
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 // NB: Don't include any other headers in this file.
  21 // LWG 2212 requires <array> to define tuple_element<cv T> specializations.
  22 #include <array>
  23
  24 void
  25 test01()
  26 {
  27   using std::array;
  28   using std::tuple_element;
  29   // This relies on the fact that <utility> includes <type_traits>:
  30   using std::is_same;
  31
  32   const std::size_t len = 3;
  33   typedef array<int, len> array_type;
  34
  35   static_assert(is_same<tuple_element<0, array_type>::type, int>::value, "" );
  36   static_assert(is_same<tuple_element<1, array_type>::type, int>::value, "" );
  37   static_assert(is_same<tuple_element<2, array_type>::type, int>::value, "");
  38
  39   static_assert(is_same<tuple_element<0, const array_type>::type,
  40                 const int>::value, "");
  41   static_assert(is_same<tuple_element<1, const array_type>::type,
  42                 const int>::value, "");
  43   static_assert(is_same<tuple_element<2, const array_type>::type,
  44                 const int>::value, "");
  45
  46   static_assert(is_same<tuple_element<0, volatile array_type>::type,
  47                 volatile int>::value, "");
  48   static_assert(is_same<tuple_element<1, volatile array_type>::type,
  49                 volatile int>::value, "");
  50   static_assert( (is_same<tuple_element<2, volatile array_type>::type,
  51            volatile int>::value == true), "" );
  52
  53   static_assert(is_same<tuple_element<0, const volatile array_type>::type,
  54                 const volatile int>::value, "");
  55   static_assert(is_same<tuple_element<1, const volatile array_type>::type,
  56                 const volatile int>::value, "");
  57   static_assert(is_same<tuple_element<2, const volatile array_type>::type,
  58                 const volatile int>::value, "");
  59 }
  60
  61 int main()
  62 {
  63   test01();
  64   return 0;
  65 }