| 1 | #ifndef BOOST_CORE_LAUNDER_HPP_INCLUDED |
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| 2 | #define BOOST_CORE_LAUNDER_HPP_INCLUDED |
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| 3 | |
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| 4 | // MS compatible compilers support #pragma once |
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| 5 | |
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| 6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
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| 7 | # pragma once |
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| 8 | #endif |
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| 9 | |
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| 10 | // Copyright 2023 Peter Dimov |
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| 11 | // Distributed under the Boost Software License, Version 1.0. |
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| 12 | // https://www.boost.org/LICENSE_1_0.txt |
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| 13 | |
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| 14 | #include <boost/config.hpp> |
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| 15 | |
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| 16 | #if defined(__has_builtin) |
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| 17 | # if __has_builtin(__builtin_launder) |
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| 18 | # define BOOST_CORE_HAS_BUILTIN_LAUNDER |
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| 19 | # endif |
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| 20 | #endif |
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| 21 | |
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| 22 | #if defined(BOOST_MSVC) && BOOST_MSVC < 1920 |
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| 23 | |
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| 24 | // msvc-14.1 suffers from internal compiler errors when using std::launder |
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| 25 | // https://github.com/boostorg/core/issues/160 |
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| 26 | // https://github.com/boostorg/optional/issues/122 |
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| 27 | |
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| 28 | #elif (BOOST_CXX_VERSION >= 201703L) && !defined(BOOST_CORE_HAS_BUILTIN_LAUNDER) |
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| 29 | |
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| 30 | #include <new> |
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| 31 | |
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| 32 | #if defined(__cpp_lib_launder) |
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| 33 | # define BOOST_CORE_HAS_STD_LAUNDER |
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| 34 | #endif |
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| 35 | |
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| 36 | #endif |
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| 37 | |
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| 38 | namespace boost |
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| 39 | { |
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| 40 | namespace core |
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| 41 | { |
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| 42 | |
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| 43 | #if defined(BOOST_CORE_HAS_BUILTIN_LAUNDER) |
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| 44 | |
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| 45 | template<class T> T* launder( T* p ) |
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| 46 | { |
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| 47 | return __builtin_launder( p ); |
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| 48 | } |
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| 49 | |
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| 50 | #elif defined(BOOST_CORE_HAS_STD_LAUNDER) |
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| 51 | |
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| 52 | template<class T> T* launder( T* p ) |
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| 53 | { |
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| 54 | return std::launder( p ); |
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| 55 | } |
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| 56 | |
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| 57 | #else |
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| 58 | |
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| 59 | template<class T> T* launder( T* p ) |
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| 60 | { |
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| 61 | return p; |
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| 62 | } |
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| 63 | |
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| 64 | #endif |
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| 65 | |
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| 66 | } // namespace core |
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| 67 | } // namespace boost |
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| 68 | |
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| 69 | #endif // #ifndef BOOST_CORE_LAUNDER_HPP_INCLUDED |
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| 70 | |
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