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