libstdc++-v3/testsuite/20_util/tuple/tuple_element_t.cc

   1 // { dg-do compile { target c++14 } }
   2 // { dg-add-options no_pch }
   3
   4 // Copyright (C) 2014-2024 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <tuple>
  22
  23 #ifndef __cpp_lib_tuple_element_t
  24 # error "Feature-test macro for tuple_element_t missing"
  25 #elif __cpp_lib_tuple_element_t != 201402
  26 # error "Feature-test macro for tuple_element_t has wrong value"
  27 #endif
  28
  29 using namespace std;
  30
  31 struct foo
  32 { };
  33
  34 int
  35 main()
  36 {
  37   // As foo isn't constructible from anything else, this
  38   // lets us check if the alias is returning foo when it should
  39   foo q1;
  40   tuple_element_t<0,tuple<foo,void,int> > q2(q1);
  41   tuple_element_t<2,tuple<void,int,foo> > q3(q1);
  42   tuple_element_t<0,const tuple<foo,void,int> > q4(q1);
  43   tuple_element_t<2,const tuple<void,int,foo> > q5(q1);
  44   tuple_element_t<0,volatile tuple<foo,void,int> > q6(q1);
  45   tuple_element_t<2,volatile tuple<void,int,foo> > q7(q1);
  46   tuple_element_t<0,const volatile tuple<foo,void,int> > q8(q1);
  47   tuple_element_t<2,const volatile tuple<void,int,foo> > q9(q1);
  48 }