in_place_index.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_UTILITY_IN_PLACE_INDEX_HPP
#define TETL_UTILITY_IN_PLACE_INDEX_HPP
 
#include <etl/_cstddef/size_t.hpp>
 
namespace etl {
 
/// \brief Disambiguation tags that can be passed to the constructors of
/// etl::optional, etl::variant, and etl::any to indicate that the contained
/// object should be constructed in-place, and (for the latter two) the type of
/// the object to be constructed.
///
/// \details The corresponding type/type templates etl::in_place_t,
/// etl::in_place_type_t and etl::in_place_index_t can be used in the
/// constructor's parameter list to match the intended tag.
template <size_t I>
struct in_place_index_t {
    explicit in_place_index_t() = default;
};
 
/// \relates in_place_index_t
template <size_t I>
inline constexpr auto in_place_index = in_place_index_t<I>{};
 
} // namespace etl
 
#endif // TETL_UTILITY_IN_PLACE_INDEX_HPP