libstdc++-v3/testsuite/20_util/optional/in_place.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
  24 #include <vector>
  25
  26 int main()
  27 {
  28   // [20.5.5] In-place construction
  29   {
  30     std::optional<int> o { std::in_place };
  31     VERIFY( o );
  32     VERIFY( *o == int() );
  33
  34     static_assert( !std::is_convertible<std::in_place_t, std::optional<int>>(), "" );
  35   }
  36
  37   {
  38     std::optional<int> o { std::in_place, 42 };
  39     VERIFY( o );
  40     VERIFY( *o == 42 );
  41   }
  42
  43   {
  44     std::optional<std::vector<int>> o { std::in_place, 18, 4 };
  45     VERIFY( o );
  46     VERIFY( o->size() == 18 );
  47     VERIFY( (*o)[17] == 4 );
  48   }
  49
  50   {
  51     std::optional<std::vector<int>> o { std::in_place, { 18, 4 } };
  52     VERIFY( o );
  53     VERIFY( o->size() == 2 );
  54     VERIFY( (*o)[0] == 18 );
  55   }
  56
  57   {
  58     std::optional<std::vector<int>> o { std::in_place, { 18, 4 }, std::allocator<int> {} };
  59     VERIFY( o );
  60     VERIFY( o->size() == 2 );
  61     VERIFY( (*o)[0] == 18 );
  62   }
  63 }