dash/src/optional.h
PastaPastaPasta 0645d47320
Merge #15292: Remove 'boost::optional'-related false positive -Wmaybe-uninitialized warnings on GCC compiler (#4635)
2d483142a7051389afe74c57a216843e6306f1a8 Remove 'boost::optional'-related gcc warnings (Hennadii Stepanov)

Pull request description:

  #14711 introduced some warnings when building with gcc compiler.

  See:
  - https://github.com/bitcoin/bitcoin/pull/14711#issuecomment-454760017 by @laanwj
  - https://github.com/bitcoin/bitcoin/pull/14711#pullrequestreview-193702611 by @ryanofsky

  This gcc [issue](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47679) has been known since version 4.6.0 and last updated in 2017.
  From the boost [docs](https://www.boost.org/doc/libs/1_69_0/libs/optional/doc/html/boost_optional/quick_start/optional_automatic_variables.html):
  > The default constructor of `optional` creates an _uninitialized_ `optional` object.

  Also: [False positive with -Wmaybe-uninitialized](https://www.boost.org/doc/libs/1_69_0/libs/optional/doc/html/boost_optional/tutorial/gotchas/false_positive_with__wmaybe_uninitialized.html) ([pointed out](https://github.com/bitcoin/bitcoin/pull/15292#issuecomment-459063170) by @Empact)

  This PR removes these warnings.

  cc: @Empact @practicalswift

Tree-SHA512: 752ae3c3ca6282bbf98726236fbc3069ab9d1aee57ae2ec2668b32e4541e7bc1acb15b7d6fa9e2b6daf1ec29c0987a1053ee1ca0f523b71367ff911221c58c94

Co-authored-by: Wladimir J. van der Laan <laanwj@gmail.com>
2021-12-22 12:59:27 +03:00

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// Copyright (c) 2017 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_OPTIONAL_H
#define BITCOIN_OPTIONAL_H
#include <utility>
#include <boost/optional.hpp>
//! Substitute for C++17 std::optional
template <typename T>
using Optional = boost::optional<T>;
//! Substitute for C++17 std::make_optional
template <typename T>
Optional<T> MakeOptional(bool condition, T&& value)
{
return boost::make_optional(condition, std::forward<T>(value));
}
//! Substitute for C++17 std::nullopt
static auto& nullopt = boost::none;
#endif // BITCOIN_OPTIONAL_H