libstdc++-v3/testsuite/20_util/optional/make_optional.cc

   1 // { dg-options "-std=gnu++17" }
   2 // { dg-do run { target c++17 }  }
   3
   4 // Copyright (C) 2013-2020 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 <optional>
  22 #include <testsuite_hooks.h>
  23 #include <vector>
  24 #include <tuple>
  25
  26 struct combined {
  27   std::vector<int> v;
  28   std::tuple<int, int> t;
  29   template<class... Args>
  30   combined(std::initializer_list<int> il, Args&&... args)
  31     : v(il), t(std::forward<Args>(args)...)
  32   {
  33   }
  34 };
  35
  36 int main()
  37 {
  38   const int i = 42;
  39   auto o = std::make_optional(i);
  40   static_assert( std::is_same<decltype(o), std::optional<int>>(), "" );
  41   VERIFY( o && *o == 42 );
  42   VERIFY( &*o != &i );
  43   auto o2 = std::make_optional<std::tuple<int, int>>(1, 2);
  44   static_assert( std::is_same<decltype(o2),
  45                  std::optional<std::tuple<int, int>>>(), "" );
  46   VERIFY( o2 && std::get<0>(*o2) == 1 && std::get<1>(*o2) == 2);
  47   auto o3 = std::make_optional<std::vector<int>>({42, 666});
  48   static_assert( std::is_same<decltype(o3),
  49                  std::optional<std::vector<int>>>(), "" );
  50   VERIFY(o3 && (*o3)[0] == 42 && (*o3)[1] == 666);
  51   auto o4 = std::make_optional<combined>({42, 666});
  52   static_assert( std::is_same<decltype(o4),
  53                  std::optional<combined>>(), "" );
  54   VERIFY(o4 && (o4->v)[0] == 42 && (o4->v)[1] == 666
  55          && std::get<0>(o4->t) == 0 && std::get<1>(o4->t) == 0 );
  56   auto o5 = std::make_optional<combined>({1, 2}, 3, 4);
  57   static_assert( std::is_same<decltype(o5),
  58                  std::optional<combined>>(), "" );
  59   VERIFY(o4 && (o5->v)[0] == 1 && (o5->v)[1] == 2
  60          && std::get<0>(o5->t) == 3 && std::get<1>(o5->t) == 4 );
  61 }