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

   1 // Copyright (C) 2016-2023 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-do run { target c++17 } }
  19
  20 #include <tuple>
  21 #include <testsuite_hooks.h>
  22
  23 #ifndef __cpp_lib_make_from_tuple
  24 # error "Feature-test macro for make_from_tuple missing."
  25 #elif __cpp_lib_make_from_tuple < 201606
  26 # error "Feature-test macro for make_from_tuple has the wrong value."
  27 #endif
  28
  29 template <class T, class U, class V>
  30 struct ThreeParam
  31 {
  32   T t;
  33   U u;
  34   V v;
  35   ThreeParam(const T& t, const U& u, const V& v)
  36     : t(t),
  37       u(u),
  38       v(v) {}
  39 };
  40
  41 void
  42 test01()
  43 {
  44   auto x = std::make_tuple(1024, 'x', 2048);
  45   ThreeParam<int, char, int> y
  46     = std::make_from_tuple<ThreeParam<int, char, int>>(x);
  47   VERIFY(y.t == 1024 && y.u == 'x' && y.v == 2048);
  48   auto x2 = std::make_tuple(4096, 'z');
  49   std::pair<int, char> z = std::make_from_tuple<std::pair<int, char>>(x2);
  50   VERIFY(z.first == 4096 && z.second == 'z');
  51   auto x3 = std::make_tuple(8192);
  52   int i = std::make_from_tuple<int>(x3);
  53   VERIFY(i == 8192);
  54 }
  55
  56 int
  57 main()
  58 {
  59   test01();
  60 }