backports-optional.hpp File Reference

Copyright (c) 2013-2016 Regents of the University of California. More...

#include "../common.hpp"
#include <boost/none.hpp>
#include <boost/optional.hpp>
#include <boost/utility/typed_in_place_factory.hpp>

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Classes
class	ndn::optional< T >
struct	ndn::in_place_t
class	ndn::nullopt_t
class	ndn::bad_optional_access
class	ndn::optional< T >

Namespaces
	ndn
	Copyright (c) 2011-2015 Regents of the University of California.

Functions
constexpr nullopt_t	ndn::nullopt (0)
template<typename T >
constexpr bool	ndn::operator== (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr bool	ndn::operator!= (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr bool	ndn::operator< (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr bool	ndn::operator<= (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr bool	ndn::operator> (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr bool	ndn::operator>= (const optional< T > &lhs, const optional< T > &rhs)
template<typename T >
constexpr optional< typename std::decay< T >::type >	ndn::make_optional (T &&value)
template<typename T , typename... Args>
constexpr optional< T >	ndn::make_optional (Args &&... args)

Variables
constexpr in_place_t	ndn::in_place {}

Detailed Description

Copyright (c) 2013-2016 Regents of the University of California.

This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).

ndn-cxx library is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

ndn-cxx 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 Lesser General Public License for more details.

You should have received copies of the GNU General Public License and GNU Lesser General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see http://www.gnu.org/licenses/.

See AUTHORS.md for complete list of ndn-cxx authors and contributors. C++17 std::optional backport implemented using boost::optional

See also

http://open-std.org/JTC1/SC22/WG21/docs/papers/2016/n4594.pdf section 20.6

http://en.cppreference.com/w/cpp/utility/optional

Differences from C++17 include:

• No constructor and operator= taking a T&&, because boost::optional lacks a move constructor as of Boost 1.54
• No constructor, operator=, emplace, and make_optional with std::initializer_list
• In-place constructor and emplace require copyable arguments, because boost::in_place requires such
• Move constructor may or may not exist (it's implicitly defined when available), because boost::optional lacks a move constructor as of Boost 1.54
• Non-const operator-> and operator* are not constexpr
• value() is not constexpr
• swap is declared without noexcept specification
• No comparison operators with const T& or nullopt_t
• No specialized std::hash support

Definition in file backports-optional.hpp.