boost/core/alignof.hpp

0001 #ifndef BOOST_CORE_ALIGNOF_HPP_INCLUDED
0002 #define BOOST_CORE_ALIGNOF_HPP_INCLUDED
0003
0004 // MS compatible compilers support #pragma once
0005
0006 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
0007 # pragma once
0008 #endif
0009
0010 //  Copyright 2023 Peter Dimov
0011 //  Distributed under the Boost Software License, Version 1.0.
0012 //  https://www.boost.org/LICENSE_1_0.txt
0013
0014 #include <boost/config.hpp>
0015 #include <cstddef>
0016
0017 #if !defined(BOOST_NO_CXX11_ALIGNOF)
0018
0019 #define BOOST_CORE_ALIGNOF alignof
0020
0021 #elif defined(__GNUC__)
0022
0023 #define BOOST_CORE_ALIGNOF __alignof__
0024
0025 #elif defined(_MSC_VER)
0026
0027 #define BOOST_CORE_ALIGNOF __alignof
0028
0029 #else
0030
0031 namespace boost
0032 {
0033 namespace core
0034 {
0035 namespace detail
0036 {
0037
0038 template<class T> struct alignof_helper
0039 {
0040     char x;
0041     T t;
0042 };
0043
0044 } // namespace detail
0045 } // namespace core
0046 } // namespace boost
0047
0048 #if defined(__GNUC__)
0049 // ignoring -Wvariadic-macros with #pragma doesn't work under GCC
0050 # pragma GCC system_header
0051 #endif
0052
0053 #define BOOST_CORE_ALIGNOF(...) offsetof( ::boost::core::detail::alignof_helper<__VA_ARGS__>, t );
0054
0055 #endif
0056
0057 #endif  // #ifndef BOOST_CORE_ALIGNOF_HPP_INCLUDED