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https://github.com/boostorg/system.git
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401 lines
10 KiB
C++
401 lines
10 KiB
C++
#ifndef BOOST_SYSTEM_DETAIL_ERROR_CODE_HPP_INCLUDED
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#define BOOST_SYSTEM_DETAIL_ERROR_CODE_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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#include <boost/system/is_error_code_enum.hpp>
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#include <boost/system/detail/error_category.hpp>
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#include <boost/system/detail/error_condition.hpp>
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#include <boost/system/detail/system_category.hpp>
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#include <boost/system/detail/system_category_impl.hpp>
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#include <boost/system/detail/interop_category.hpp>
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#include <boost/system/detail/enable_if.hpp>
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#include <boost/system/detail/is_same.hpp>
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#include <boost/system/detail/snprintf.hpp>
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#include <boost/system/detail/config.hpp>
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#include <boost/cstdint.hpp>
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#include <boost/config.hpp>
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#include <ostream>
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#include <new>
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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# include <system_error>
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#endif
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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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// We want error_code to be a value type that can be copied without slicing
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// and without requiring heap allocation, but we also want it to have
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// polymorphic behavior based on the error category. This is achieved by
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// abstract base class error_category supplying the polymorphic behavior,
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// and error_code containing a pointer to an object of a type derived
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// from error_category.
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std::size_t hash_value( error_code const & ec );
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class error_code
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{
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private:
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friend std::size_t hash_value( error_code const & ec );
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private:
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struct data
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{
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int val_;
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const error_category * cat_;
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};
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union
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{
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data d1_;
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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unsigned char d2_[ sizeof(std::error_code) ];
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#endif
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};
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// 0: default constructed, d1_ value initialized
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// 1: holds std::error_code in d2_
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// 2: holds error code in d1_, failed == false
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// 3: holds error code in d1_, failed == true
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unsigned flags_;
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public:
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// constructors:
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BOOST_SYSTEM_CONSTEXPR error_code() BOOST_NOEXCEPT:
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d1_(), flags_( 0 )
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{
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}
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BOOST_SYSTEM_CONSTEXPR error_code( int val, const error_category & cat ) BOOST_NOEXCEPT:
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d1_(), flags_( 2 + detail::failed_impl( val, cat ) )
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{
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d1_.val_ = val;
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d1_.cat_ = &cat;
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}
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template<class ErrorCodeEnum> BOOST_SYSTEM_CONSTEXPR error_code( ErrorCodeEnum e,
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typename detail::enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type* = 0 ) BOOST_NOEXCEPT
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{
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*this = make_error_code( e );
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}
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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error_code( std::error_code const& ec ) BOOST_NOEXCEPT:
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flags_( 1 )
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{
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::new( d2_ ) std::error_code( ec );
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}
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#endif
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// modifiers:
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BOOST_SYSTEM_CONSTEXPR void assign( int val, const error_category & cat ) BOOST_NOEXCEPT
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{
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*this = error_code( val, cat );
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}
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template<typename ErrorCodeEnum>
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BOOST_SYSTEM_CONSTEXPR typename detail::enable_if<is_error_code_enum<ErrorCodeEnum>::value, error_code>::type &
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operator=( ErrorCodeEnum val ) BOOST_NOEXCEPT
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{
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*this = make_error_code( val );
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return *this;
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}
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BOOST_SYSTEM_CONSTEXPR void clear() BOOST_NOEXCEPT
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{
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*this = error_code();
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}
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// observers:
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BOOST_SYSTEM_CONSTEXPR int value() const BOOST_NOEXCEPT
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{
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if( flags_ != 1 )
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{
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return d1_.val_;
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}
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else
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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std::error_code const& ec = *reinterpret_cast<std::error_code const*>( d2_ );
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return ec.value() + 1000 * static_cast<unsigned>( reinterpret_cast<boost::uintptr_t>( &ec.category() ) % 2097143 ); // 2^21-9, prime
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#else
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return -1;
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#endif
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}
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}
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BOOST_SYSTEM_CONSTEXPR const error_category & category() const BOOST_NOEXCEPT
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{
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if( flags_ == 0 )
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{
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return system_category();
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}
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else if( flags_ == 1 )
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{
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return detail::interop_category();
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}
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else
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{
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return *d1_.cat_;
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}
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}
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// deprecated?
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error_condition default_error_condition() const BOOST_NOEXCEPT
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{
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return category().default_error_condition( value() );
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}
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std::string message() const
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( flags_ == 1 )
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{
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std::error_code const& ec = *reinterpret_cast<std::error_code const*>( d2_ );
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return ec.message();
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}
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#endif
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return category().message( value() );
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}
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char const * message( char * buffer, std::size_t len ) const BOOST_NOEXCEPT
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( flags_ == 1 )
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{
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#if !defined(BOOST_NO_EXCEPTIONS)
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try
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#endif
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{
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std::error_code const& ec = *reinterpret_cast<std::error_code const*>( d2_ );
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detail::snprintf( buffer, len, "%s", ec.message().c_str() );
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return buffer;
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}
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#if !defined(BOOST_NO_EXCEPTIONS)
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catch( ... )
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{
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}
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#endif
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}
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#endif
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return category().message( value(), buffer, len );
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}
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BOOST_SYSTEM_CONSTEXPR bool failed() const BOOST_NOEXCEPT
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( flags_ == 1 )
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{
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std::error_code const& ec = *reinterpret_cast<std::error_code const*>( d2_ );
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return ec.value() != 0;
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}
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else
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#endif
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{
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return (flags_ & 1) != 0;
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}
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}
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#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
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BOOST_SYSTEM_CONSTEXPR explicit operator bool() const BOOST_NOEXCEPT // true if error
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{
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return failed();
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}
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#else
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typedef void (*unspecified_bool_type)();
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static void unspecified_bool_true() {}
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BOOST_SYSTEM_CONSTEXPR operator unspecified_bool_type() const BOOST_NOEXCEPT // true if error
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{
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return failed()? unspecified_bool_true: 0;
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}
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BOOST_SYSTEM_CONSTEXPR bool operator!() const BOOST_NOEXCEPT // true if no error
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{
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return !failed();
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}
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#endif
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// relationals:
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// the more symmetrical non-member syntax allows enum
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// conversions work for both rhs and lhs.
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BOOST_SYSTEM_CONSTEXPR inline friend bool operator==( const error_code & lhs, const error_code & rhs ) BOOST_NOEXCEPT
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( lhs.flags_ == 1 && rhs.flags_ == 1 )
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{
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std::error_code const& e1 = *reinterpret_cast<std::error_code const*>( lhs.d2_ );
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std::error_code const& e2 = *reinterpret_cast<std::error_code const*>( rhs.d2_ );
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return e1 == e2;
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}
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else
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#endif
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{
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return lhs.value() == rhs.value() && lhs.category() == rhs.category();
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}
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}
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BOOST_SYSTEM_CONSTEXPR inline friend bool operator<( const error_code & lhs, const error_code & rhs ) BOOST_NOEXCEPT
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( lhs.flags_ == 1 && rhs.flags_ == 1 )
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{
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std::error_code const& e1 = *reinterpret_cast<std::error_code const*>( lhs.d2_ );
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std::error_code const& e2 = *reinterpret_cast<std::error_code const*>( rhs.d2_ );
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return e1 < e2;
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}
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else
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#endif
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{
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return lhs.category() < rhs.category() || (lhs.category() == rhs.category() && lhs.value() < rhs.value());
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}
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}
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BOOST_SYSTEM_CONSTEXPR inline friend bool operator!=( const error_code & lhs, const error_code & rhs ) BOOST_NOEXCEPT
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{
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return !( lhs == rhs );
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}
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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operator std::error_code () const
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{
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if( flags_ == 1 )
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{
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return *reinterpret_cast<std::error_code const*>( d2_ );
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}
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else if( flags_ == 0 )
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{
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//return std::error_code();
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return std::error_code( 0, boost::system::system_category() );
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}
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else
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{
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return std::error_code( d1_.val_, *d1_.cat_ );
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}
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}
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operator std::error_code ()
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{
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return const_cast<error_code const&>( *this );
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}
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template<class T,
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class E = typename detail::enable_if<detail::is_same<T, std::error_code>::value>::type>
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operator T& ()
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{
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if( flags_ != 1 )
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{
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std::error_code e2 = *this;
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::new( d2_ ) std::error_code( e2 );
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flags_ = 1;
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}
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return *reinterpret_cast<std::error_code*>( d2_ );
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}
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#endif
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template<class Ch, class Tr>
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inline friend std::basic_ostream<Ch, Tr>&
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operator<< (std::basic_ostream<Ch, Tr>& os, error_code const & ec)
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( ec.flags_ == 1 )
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{
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std::error_code const& e2 = *reinterpret_cast<std::error_code const*>( ec.d2_ );
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os << "std:" << e2.category().name() << ':' << e2.value();
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}
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else
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#endif
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{
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os << ec.category().name() << ':' << ec.value();
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}
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return os;
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}
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};
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inline std::size_t hash_value( error_code const & ec )
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{
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#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
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if( ec.flags_ == 1 )
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{
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std::error_code const& e2 = *reinterpret_cast<std::error_code const*>( ec.d2_ );
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return std::hash<std::error_code>()( e2 );
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}
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#endif
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error_category const & cat = ec.category();
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boost::ulong_long_type id_ = cat.id_;
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if( id_ == 0 )
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{
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id_ = reinterpret_cast<boost::uintptr_t>( &cat );
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}
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boost::ulong_long_type hv = ( boost::ulong_long_type( 0xCBF29CE4 ) << 32 ) + 0x84222325;
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boost::ulong_long_type const prime = ( boost::ulong_long_type( 0x00000100 ) << 32 ) + 0x000001B3;
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// id
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hv ^= id_;
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hv *= prime;
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// value
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hv ^= static_cast<unsigned>( ec.value() );
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hv *= prime;
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return static_cast<std::size_t>( hv );
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}
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} // namespace system
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} // namespace boost
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#endif // #ifndef BOOST_SYSTEM_DETAIL_ERROR_CODE_HPP_INCLUDED
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