libstdc++-v3/testsuite/20_util/tuple/make_from_tuple/1.cc

   1 // Copyright (C) 2016-2020 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do run { target c++17 } }
  20
  21 #include <tuple>
  22 #include <testsuite_hooks.h>
  23
  24 #ifndef __cpp_lib_make_from_tuple
  25 # error "Feature-test macro for make_from_tuple missing."
  26 #elif __cpp_lib_make_from_tuple < 201606
  27 # error "Feature-test macro for make_from_tuple has the wrong value."
  28 #endif
  29
  30 template <class T, class U, class V>
  31 struct ThreeParam
  32 {
  33   T t;
  34   U u;
  35   V v;
  36   ThreeParam(const T& t, const U& u, const V& v)
  37     : t(t),
  38       u(u),
  39       v(v) {}
  40 };
  41
  42 void
  43 test01()
  44 {
  45   auto x = std::make_tuple(1024, 'x', 2048);
  46   ThreeParam<int, char, int> y
  47     = std::make_from_tuple<ThreeParam<int, char, int>>(x);
  48   VERIFY(y.t == 1024 && y.u == 'x' && y.v == 2048);
  49   auto x2 = std::make_tuple(4096, 'z');
  50   std::pair<int, char> z = std::make_from_tuple<std::pair<int, char>>(x2);
  51   VERIFY(z.first == 4096 && z.second == 'z');
  52   auto x3 = std::make_tuple(8192);
  53   int i = std::make_from_tuple<int>(x3);
  54   VERIFY(i == 8192);
  55 }
  56
  57 int
  58 main()
  59 {
  60   test01();
  61 }