llvm/libc/src/__support/CPP/optional.h

//===-- Standalone implementation of std::optional --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_OPTIONAL_H
#define LLVM_LIBC_SRC___SUPPORT_CPP_OPTIONAL_H

#include "src/__support/CPP/type_traits.h"
#include "src/__support/CPP/utility.h"
#include "src/__support/macros/attributes.h"
#include "src/__support/macros/config.h"

namespace LIBC_NAMESPACE_DECL {
namespace cpp {

// Trivial nullopt_t struct.
struct nullopt_t { … };

// nullopt that can be used and returned.
LIBC_INLINE_VAR constexpr nullopt_t nullopt{ … };

// This is very simple implementation of the std::optional class. It makes
// several assumptions that the underlying type is trivially constructible,
// copyable, or movable.
template <typename T> class optional { … };

} // namespace cpp
} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC___SUPPORT_CPP_OPTIONAL_H