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- #ifndef BOOST_SYSTEM_DETAIL_THROWS_HPP_INCLUDED
- #define BOOST_SYSTEM_DETAIL_THROWS_HPP_INCLUDED
- // Copyright Beman Dawes 2006, 2007
- // Copyright Christoper Kohlhoff 2007
- // Copyright Peter Dimov 2017, 2018
- //
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- //
- // See library home page at http://www.boost.org/libs/system
- namespace boost
- {
- namespace system
- {
- class error_code;
- } // namespace system
- // boost::throws()
- namespace detail
- {
- // Misuse of the error_code object is turned into a noisy failure by
- // poisoning the reference. This particular implementation doesn't
- // produce warnings or errors from popular compilers, is very efficient
- // (as determined by inspecting generated code), and does not suffer
- // from order of initialization problems. In practice, it also seems
- // cause user function error handling implementation errors to be detected
- // very early in the development cycle.
- inline system::error_code* throws()
- {
- // See github.com/boostorg/system/pull/12 by visigoth for why the return
- // is poisoned with nonzero rather than (0). A test, test_throws_usage(),
- // has been added to error_code_test.cpp, and as visigoth mentioned it
- // fails on clang for release builds with a return of 0 but works fine
- // with (1).
- // Since the undefined behavior sanitizer (-fsanitize=undefined) does not
- // allow a reference to be formed to the unaligned address of (1), we use
- // (8) instead.
- return reinterpret_cast<system::error_code*>(8);
- }
- } // namespace detail
- inline system::error_code& throws()
- {
- return *detail::throws();
- }
- } // namespace boost
- #endif // #ifndef BOOST_SYSTEM_DETAIL_THROWS_HPP_INCLUDED
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