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// <system_error> -*- C++ -*- |
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|
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// Copyright (C) 2007-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** @file include/system_error |
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* This is a Standard C++ Library header. |
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*/ |
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|
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#ifndef _GLIBCXX_SYSTEM_ERROR |
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#define _GLIBCXX_SYSTEM_ERROR 1 |
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|
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#pragma GCC system_header |
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|
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#if __cplusplus < 201103L |
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# include <bits/c++0x_warning.h> |
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#else |
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|
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#include <bits/c++config.h> |
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#include <bits/error_constants.h> |
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#include <iosfwd> |
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#include <stdexcept> |
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#if __cplusplus > 201703L |
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# include <compare> |
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#endif |
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|
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namespace std _GLIBCXX_VISIBILITY(default) |
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{ |
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_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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|
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/** @addtogroup diagnostics |
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* @{ |
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*/ |
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|
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class error_code; |
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class error_condition; |
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class system_error; |
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|
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/// is_error_code_enum |
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template<typename _Tp> |
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struct is_error_code_enum : public false_type { }; |
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|
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/// is_error_condition_enum |
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template<typename _Tp> |
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struct is_error_condition_enum : public false_type { }; |
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|
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template<> |
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struct is_error_condition_enum<errc> |
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: public true_type { }; |
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|
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#if __cplusplus > 201402L |
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template <typename _Tp> |
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inline constexpr bool is_error_code_enum_v = |
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is_error_code_enum<_Tp>::value; |
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template <typename _Tp> |
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inline constexpr bool is_error_condition_enum_v = |
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is_error_condition_enum<_Tp>::value; |
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#endif // C++17 |
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inline namespace _V2 { |
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|
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/** Abstract base class for types defining a category of error codes. |
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* |
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* An error category defines a context that give meaning to the integer |
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* stored in an `error_code` or `error_condition` object. For example, |
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* the standard `errno` constants such a `EINVAL` and `ENOMEM` are |
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* associated with the "generic" category and other OS-specific error |
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* numbers are associated with the "system" category, but a user-defined |
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* category might give different meanings to the same numerical values. |
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*/ |
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class error_category |
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{ |
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public: |
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constexpr error_category() noexcept = default; |
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|
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virtual ~error_category(); |
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|
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error_category(const error_category&) = delete; |
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error_category& operator=(const error_category&) = delete; |
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|
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virtual const char* |
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name() const noexcept = 0; |
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|
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// We need two different virtual functions here, one returning a |
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// COW string and one returning an SSO string. Their positions in the |
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// vtable must be consistent for dynamic dispatch to work, but which one |
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// the name "message()" finds depends on which ABI the caller is using. |
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#if _GLIBCXX_USE_CXX11_ABI |
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private: |
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_GLIBCXX_DEFAULT_ABI_TAG |
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virtual __cow_string |
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_M_message(int) const; |
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|
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public: |
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_GLIBCXX_DEFAULT_ABI_TAG |
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virtual string |
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message(int) const = 0; |
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#else |
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virtual string |
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message(int) const = 0; |
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|
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private: |
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virtual __sso_string |
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_M_message(int) const; |
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#endif |
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|
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public: |
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virtual error_condition |
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default_error_condition(int __i) const noexcept; |
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|
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virtual bool |
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equivalent(int __i, const error_condition& __cond) const noexcept; |
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|
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virtual bool |
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equivalent(const error_code& __code, int __i) const noexcept; |
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|
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bool |
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operator==(const error_category& __other) const noexcept |
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{ return this == &__other; } |
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|
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#if __cpp_lib_three_way_comparison |
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strong_ordering |
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operator<=>(const error_category& __rhs) const noexcept |
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{ return std::compare_three_way()(this, &__rhs); } |
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#else |
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bool |
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operator!=(const error_category& __other) const noexcept |
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{ return this != &__other; } |
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|
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bool |
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operator<(const error_category& __other) const noexcept |
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{ return less<const error_category*>()(this, &__other); } |
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#endif |
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}; |
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|
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// DR 890. |
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|
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/// Error category for `errno` error codes. |
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_GLIBCXX_CONST const error_category& generic_category() noexcept; |
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|
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/// Error category for other error codes defined by the OS. |
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_GLIBCXX_CONST const error_category& system_category() noexcept; |
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|
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} // end inline namespace |
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|
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error_code make_error_code(errc) noexcept; |
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|
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/** Class error_code |
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* |
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* This class is a value type storing an integer error number and a |
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* category that gives meaning to the error number. Typically this is done |
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* close the the point where the error happens, to capture the original |
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* error value. |
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* |
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* An `error_code` object can be used to store the original error value |
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* emitted by some subsystem, with a category relevant to the subsystem. |
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* For example, errors from POSIX library functions can be represented by |
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* an `errno` value and the "generic" category, but errors from an HTTP |
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* library might be represented by an HTTP response status code (e.g. 404) |
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* and a custom category defined by the library. |
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*/ |
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class error_code |
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{ |
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public: |
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error_code() noexcept |
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: _M_value(0), _M_cat(&system_category()) { } |
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|
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error_code(int __v, const error_category& __cat) noexcept |
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: _M_value(__v), _M_cat(&__cat) { } |
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|
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template<typename _ErrorCodeEnum, typename = typename |
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enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type> |
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error_code(_ErrorCodeEnum __e) noexcept |
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{ *this = make_error_code(__e); } |
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|
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void |
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assign(int __v, const error_category& __cat) noexcept |
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{ |
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_M_value = __v; |
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_M_cat = &__cat; |
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} |
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|
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void |
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clear() noexcept |
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{ assign(0, system_category()); } |
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|
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// DR 804. |
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template<typename _ErrorCodeEnum> |
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typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value, |
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error_code&>::type |
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operator=(_ErrorCodeEnum __e) noexcept |
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{ return *this = make_error_code(__e); } |
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|
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int |
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value() const noexcept { return _M_value; } |
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|
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const error_category& |
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category() const noexcept { return *_M_cat; } |
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|
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error_condition |
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default_error_condition() const noexcept; |
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|
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_GLIBCXX_DEFAULT_ABI_TAG |
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string |
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message() const |
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{ return category().message(value()); } |
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|
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explicit operator bool() const noexcept |
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{ return _M_value != 0; } |
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|
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// DR 804. |
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private: |
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int _M_value; |
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const error_category* _M_cat; |
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}; |
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|
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// 19.4.2.6 non-member functions |
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|
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/// @relates error_code @{ |
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|
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inline error_code |
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make_error_code(errc __e) noexcept |
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{ return error_code(static_cast<int>(__e), generic_category()); } |
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|
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#if __cpp_lib_three_way_comparison |
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inline strong_ordering |
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operator<=>(const error_code& __lhs, const error_code& __rhs) noexcept |
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{ |
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if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0) |
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return __c; |
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return __lhs.value() <=> __rhs.value(); |
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} |
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#else |
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inline bool |
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operator<(const error_code& __lhs, const error_code& __rhs) noexcept |
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{ |
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return (__lhs.category() < __rhs.category() |
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|| (__lhs.category() == __rhs.category() |
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&& __lhs.value() < __rhs.value())); |
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} |
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#endif |
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|
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template<typename _CharT, typename _Traits> |
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basic_ostream<_CharT, _Traits>& |
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operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e) |
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{ return (__os << __e.category().name() << ':' << __e.value()); } |
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|
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/// @} |
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|
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error_condition make_error_condition(errc) noexcept; |
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|
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/** Class error_condition |
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* |
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* This class represents error conditions that may be visible at an API |
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* boundary. Different `error_code` values that can occur within a library |
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* or module might map to the same `error_condition`. |
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* |
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* An `error_condition` represents something that the program can test for, |
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* and subsequently take appropriate action. |
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*/ |
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class error_condition |
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{ |
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public: |
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error_condition() noexcept |
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: _M_value(0), _M_cat(&generic_category()) { } |
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|
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error_condition(int __v, const error_category& __cat) noexcept |
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: _M_value(__v), _M_cat(&__cat) { } |
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|
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template<typename _ErrorConditionEnum, typename = typename |
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enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type> |
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error_condition(_ErrorConditionEnum __e) noexcept |
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{ *this = make_error_condition(__e); } |
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|
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void |
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assign(int __v, const error_category& __cat) noexcept |
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{ |
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_M_value = __v; |
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_M_cat = &__cat; |
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} |
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|
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// DR 804. |
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template<typename _ErrorConditionEnum> |
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typename enable_if<is_error_condition_enum |
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<_ErrorConditionEnum>::value, error_condition&>::type |
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operator=(_ErrorConditionEnum __e) noexcept |
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{ return *this = make_error_condition(__e); } |
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|
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void |
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clear() noexcept |
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{ assign(0, generic_category()); } |
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|
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// 19.4.3.4 observers |
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int |
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value() const noexcept { return _M_value; } |
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|
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const error_category& |
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category() const noexcept { return *_M_cat; } |
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|
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_GLIBCXX_DEFAULT_ABI_TAG |
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string |
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message() const |
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{ return category().message(value()); } |
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|
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explicit operator bool() const noexcept |
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{ return _M_value != 0; } |
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|
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// DR 804. |
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private: |
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int _M_value; |
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const error_category* _M_cat; |
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}; |
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|
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// 19.4.3.6 non-member functions |
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|
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/// Create an `error_condition` representing a standard `errc` condition. |
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/// @relates error_condition |
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inline error_condition |
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make_error_condition(errc __e) noexcept |
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{ return error_condition(static_cast<int>(__e), generic_category()); } |
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|
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// 19.4.4 Comparison operators |
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|
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/// @relates error_code |
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inline bool |
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operator==(const error_code& __lhs, const error_code& __rhs) noexcept |
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{ return (__lhs.category() == __rhs.category() |
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&& __lhs.value() == __rhs.value()); } |
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|
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/// @relates error_code |
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/// @relates error_condition |
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inline bool |
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operator==(const error_code& __lhs, const error_condition& __rhs) noexcept |
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{ |
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return (__lhs.category().equivalent(__lhs.value(), __rhs) |
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|| __rhs.category().equivalent(__lhs, __rhs.value())); |
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} |
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|
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/// @relates error_condition |
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inline bool |
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operator==(const error_condition& __lhs, |
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const error_condition& __rhs) noexcept |
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{ |
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return (__lhs.category() == __rhs.category() |
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&& __lhs.value() == __rhs.value()); |
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} |
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|
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#if __cpp_lib_three_way_comparison |
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/// Define an ordering for error_condition objects. |
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/// @relates error_condition |
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inline strong_ordering |
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operator<=>(const error_condition& __lhs, |
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const error_condition& __rhs) noexcept |
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{ |
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if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0) |
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return __c; |
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return __lhs.value() <=> __rhs.value(); |
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} |
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#else |
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/// Define an ordering for error_condition objects. |
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/// @relates error_condition |
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inline bool |
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operator<(const error_condition& __lhs, |
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const error_condition& __rhs) noexcept |
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{ |
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return (__lhs.category() < __rhs.category() |
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|| (__lhs.category() == __rhs.category() |
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&& __lhs.value() < __rhs.value())); |
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} |
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|
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/// @relates error_code |
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/// @relates error_condition |
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inline bool |
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operator==(const error_condition& __lhs, const error_code& __rhs) noexcept |
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{ |
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return (__rhs.category().equivalent(__rhs.value(), __lhs) |
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|| __lhs.category().equivalent(__rhs, __lhs.value())); |
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} |
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|
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/// @relates error_code |
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inline bool |
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operator!=(const error_code& __lhs, const error_code& __rhs) noexcept |
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{ return !(__lhs == __rhs); } |
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|
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/// @relates error_code |
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/// @relates error_condition |
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inline bool |
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operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept |
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{ return !(__lhs == __rhs); } |
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|
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/// @relates error_code |
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/// @relates error_condition |
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inline bool |
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operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept |
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{ return !(__lhs == __rhs); } |
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|
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/// @relates error_condition |
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inline bool |
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operator!=(const error_condition& __lhs, |
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const error_condition& __rhs) noexcept |
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{ return !(__lhs == __rhs); } |
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#endif // three_way_comparison |
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|
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/** |
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* @brief An exception type that includes an `error_code` value. |
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* |
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* Typically used to report errors from the operating system and other |
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* low-level APIs. |
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* |
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* @ingroup exceptions |
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*/ |
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class system_error : public std::runtime_error |
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{ |
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private: |
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error_code _M_code; |
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|
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public: |
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system_error(error_code __ec = error_code()) |
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: runtime_error(__ec.message()), _M_code(__ec) { } |
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|
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system_error(error_code __ec, const string& __what) |
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: runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { } |
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|
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system_error(error_code __ec, const char* __what) |
| 443 |
: runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { } |
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|
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system_error(int __v, const error_category& __ecat, const char* __what) |
| 446 |
: system_error(error_code(__v, __ecat), __what) { } |
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|
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system_error(int __v, const error_category& __ecat) |
| 449 |
: runtime_error(error_code(__v, __ecat).message()), |
| 450 |
_M_code(__v, __ecat) { } |
| 451 |
|
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system_error(int __v, const error_category& __ecat, const string& __what) |
| 453 |
: runtime_error(__what + ": " + error_code(__v, __ecat).message()), |
| 454 |
_M_code(__v, __ecat) { } |
| 455 |
|
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#if __cplusplus >= 201103L |
| 457 |
system_error (const system_error &) = default; |
| 458 |
system_error &operator= (const system_error &) = default; |
| 459 |
#endif |
| 460 |
|
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virtual ~system_error() noexcept; |
| 462 |
|
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const error_code& |
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code() const noexcept { return _M_code; } |
| 465 |
}; |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
| 468 |
} // namespace |
| 469 |
|
| 470 |
#include <bits/functional_hash.h> |
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|
| 472 |
namespace std _GLIBCXX_VISIBILITY(default) |
| 473 |
{ |
| 474 |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
| 475 |
|
| 476 |
#ifndef _GLIBCXX_COMPATIBILITY_CXX0X |
| 477 |
// DR 1182. |
| 478 |
/// std::hash specialization for error_code. |
| 479 |
/// @relates error_code |
| 480 |
template<> |
| 481 |
struct hash<error_code> |
| 482 |
: public __hash_base<size_t, error_code> |
| 483 |
{ |
| 484 |
size_t |
| 485 |
operator()(const error_code& __e) const noexcept |
| 486 |
{ |
| 487 |
const size_t __tmp = std::_Hash_impl::hash(__e.value()); |
| 488 |
return std::_Hash_impl::__hash_combine(&__e.category(), __tmp); |
| 489 |
} |
| 490 |
}; |
| 491 |
#endif // _GLIBCXX_COMPATIBILITY_CXX0X |
| 492 |
|
| 493 |
#if __cplusplus >= 201703L |
| 494 |
// DR 2686. |
| 495 |
/// std::hash specialization for error_condition. |
| 496 |
/// @relates error_condition |
| 497 |
template<> |
| 498 |
struct hash<error_condition> |
| 499 |
: public __hash_base<size_t, error_condition> |
| 500 |
{ |
| 501 |
size_t |
| 502 |
operator()(const error_condition& __e) const noexcept |
| 503 |
{ |
| 504 |
const size_t __tmp = std::_Hash_impl::hash(__e.value()); |
| 505 |
return std::_Hash_impl::__hash_combine(&__e.category(), __tmp); |
| 506 |
} |
| 507 |
}; |
| 508 |
#endif |
| 509 |
|
| 510 |
_GLIBCXX_END_NAMESPACE_VERSION |
| 511 |
} // namespace |
| 512 |
|
| 513 |
#endif // C++11 |
| 514 |
|
| 515 |
#endif // _GLIBCXX_SYSTEM_ERROR |
