Retro68/gcc/libstdc++-v3/testsuite/20_util/optional/nullopt.cc
Wolfgang Thaller 6fbf4226da gcc-9.1
2019-06-20 20:10:10 +02:00

47 lines
1.4 KiB
C++

// { dg-options "-std=gnu++17" }
// { dg-do run { target c++17 } }
// Copyright (C) 2013-2019 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
#include <optional>
#include <testsuite_hooks.h>
int main()
{
// [20.5.6] Disengaged state indicator
static_assert( std::is_same<decltype(std::nullopt), const std::nullopt_t>(), "" );
static_assert( std::is_empty<std::nullopt_t>(), "" );
static_assert( std::is_literal_type<std::nullopt_t>(), "" );
static_assert( !std::is_default_constructible<std::nullopt_t>(), "" );
{
std::optional<int> o = std::nullopt;
VERIFY( !o );
}
{
std::optional<int> o = { std::nullopt };
VERIFY( !o );
}
{
std::optional<int> o { std::nullopt };
VERIFY( !o );
}
}