1// <system_error> -*- C++ -*-
2
3// Copyright (C) 2007-2018 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/system_error
26 *  This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_SYSTEM_ERROR
30#define _GLIBCXX_SYSTEM_ERROR 1
31
32#pragma GCC system_header
33
34#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <bits/c++config.h>
39#include <bits/error_constants.h>
40#include <iosfwd>
41#include <stdexcept>
42
43namespace std _GLIBCXX_VISIBILITY(default)
44{
45_GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47  class error_code;
48  class error_condition;
49  class system_error;
50
51  /// is_error_code_enum
52  template<typename _Tp>
53    struct is_error_code_enum : public false_type { };
54
55  /// is_error_condition_enum
56  template<typename _Tp>
57    struct is_error_condition_enum : public false_type { };
58
59  template<>
60    struct is_error_condition_enum<errc>
61    : public true_type { };
62
63#if __cplusplus > 201402L
64  template <typename _Tp>
65    inline constexpr bool is_error_code_enum_v =
66      is_error_code_enum<_Tp>::value;
67  template <typename _Tp>
68    inline constexpr bool is_error_condition_enum_v =
69      is_error_condition_enum<_Tp>::value;
70#endif // C++17
71  inline namespace _V2 {
72
73  /// error_category
74  class error_category
75  {
76  public:
77    constexpr error_category() noexcept = default;
78
79    virtual ~error_category();
80
81    error_category(const error_category&) = delete;
82    error_category& operator=(const error_category&) = delete;
83
84    virtual const char*
85    name() const noexcept = 0;
86
87    // We need two different virtual functions here, one returning a
88    // COW string and one returning an SSO string. Their positions in the
89    // vtable must be consistent for dynamic dispatch to work, but which one
90    // the name "message()" finds depends on which ABI the caller is using.
91#if _GLIBCXX_USE_CXX11_ABI
92  private:
93    _GLIBCXX_DEFAULT_ABI_TAG
94    virtual __cow_string
95    _M_message(int) const;
96
97  public:
98    _GLIBCXX_DEFAULT_ABI_TAG
99    virtual string
100    message(int) const = 0;
101#else
102    virtual string
103    message(int) const = 0;
104
105  private:
106    virtual __sso_string
107    _M_message(int) const;
108#endif
109
110  public:
111    virtual error_condition
112    default_error_condition(int __i) const noexcept;
113
114    virtual bool
115    equivalent(int __i, const error_condition& __cond) const noexcept;
116
117    virtual bool
118    equivalent(const error_code& __code, int __i) const noexcept;
119
120    bool
121    operator<(const error_category& __other) const noexcept
122    { return less<const error_category*>()(this, &__other); }
123
124    bool
125    operator==(const error_category& __other) const noexcept
126    { return this == &__other; }
127
128    bool
129    operator!=(const error_category& __other) const noexcept
130    { return this != &__other; }
131  };
132
133  // DR 890.
134  _GLIBCXX_CONST const error_category& system_category() noexcept;
135  _GLIBCXX_CONST const error_category& generic_category() noexcept;
136
137  } // end inline namespace
138
139  error_code make_error_code(errc) noexcept;
140
141  template<typename _Tp>
142    struct hash;
143
144  /// error_code
145  // Implementation-specific error identification
146  struct error_code
147  {
148    error_code() noexcept
149    : _M_value(0), _M_cat(&system_category()) { }
150
151    error_code(int __v, const error_category& __cat) noexcept
152    : _M_value(__v), _M_cat(&__cat) { }
153
154    template<typename _ErrorCodeEnum, typename = typename
155	     enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
156      error_code(_ErrorCodeEnum __e) noexcept
157      { *this = make_error_code(__e); }
158
159    void
160    assign(int __v, const error_category& __cat) noexcept
161    {
162      _M_value = __v;
163      _M_cat = &__cat;
164    }
165
166    void
167    clear() noexcept
168    { assign(0, system_category()); }
169
170    // DR 804.
171    template<typename _ErrorCodeEnum>
172      typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value,
173			 error_code&>::type
174      operator=(_ErrorCodeEnum __e) noexcept
175      { return *this = make_error_code(__e); }
176
177    int
178    value() const noexcept { return _M_value; }
179
180    const error_category&
181    category() const noexcept { return *_M_cat; }
182
183    error_condition
184    default_error_condition() const noexcept;
185
186    _GLIBCXX_DEFAULT_ABI_TAG
187    string
188    message() const
189    { return category().message(value()); }
190
191    explicit operator bool() const noexcept
192    { return _M_value != 0; }
193
194    // DR 804.
195  private:
196    friend class hash<error_code>;
197
198    int            		_M_value;
199    const error_category* 	_M_cat;
200  };
201
202  // 19.4.2.6 non-member functions
203  inline error_code
204  make_error_code(errc __e) noexcept
205  { return error_code(static_cast<int>(__e), generic_category()); }
206
207  inline bool
208  operator<(const error_code& __lhs, const error_code& __rhs) noexcept
209  {
210    return (__lhs.category() < __rhs.category()
211	    || (__lhs.category() == __rhs.category()
212		&& __lhs.value() < __rhs.value()));
213  }
214
215  template<typename _CharT, typename _Traits>
216    basic_ostream<_CharT, _Traits>&
217    operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
218    { return (__os << __e.category().name() << ':' << __e.value()); }
219
220  error_condition make_error_condition(errc) noexcept;
221
222  /// error_condition
223  // Portable error identification
224  struct error_condition
225  {
226    error_condition() noexcept
227    : _M_value(0), _M_cat(&generic_category()) { }
228
229    error_condition(int __v, const error_category& __cat) noexcept
230    : _M_value(__v), _M_cat(&__cat) { }
231
232    template<typename _ErrorConditionEnum, typename = typename
233	 enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type>
234      error_condition(_ErrorConditionEnum __e) noexcept
235      { *this = make_error_condition(__e); }
236
237    void
238    assign(int __v, const error_category& __cat) noexcept
239    {
240      _M_value = __v;
241      _M_cat = &__cat;
242    }
243
244    // DR 804.
245    template<typename _ErrorConditionEnum>
246      typename enable_if<is_error_condition_enum
247			 <_ErrorConditionEnum>::value, error_condition&>::type
248      operator=(_ErrorConditionEnum __e) noexcept
249      { return *this = make_error_condition(__e); }
250
251    void
252    clear() noexcept
253    { assign(0, generic_category()); }
254
255    // 19.4.3.4 observers
256    int
257    value() const noexcept { return _M_value; }
258
259    const error_category&
260    category() const noexcept { return *_M_cat; }
261
262    _GLIBCXX_DEFAULT_ABI_TAG
263    string
264    message() const
265    { return category().message(value()); }
266
267    explicit operator bool() const noexcept
268    { return _M_value != 0; }
269
270    // DR 804.
271  private:
272    int 			_M_value;
273    const error_category* 	_M_cat;
274  };
275
276  // 19.4.3.6 non-member functions
277  inline error_condition
278  make_error_condition(errc __e) noexcept
279  { return error_condition(static_cast<int>(__e), generic_category()); }
280
281  inline bool
282  operator<(const error_condition& __lhs,
283	    const error_condition& __rhs) noexcept
284  {
285    return (__lhs.category() < __rhs.category()
286	    || (__lhs.category() == __rhs.category()
287		&& __lhs.value() < __rhs.value()));
288  }
289
290  // 19.4.4 Comparison operators
291  inline bool
292  operator==(const error_code& __lhs, const error_code& __rhs) noexcept
293  { return (__lhs.category() == __rhs.category()
294	    && __lhs.value() == __rhs.value()); }
295
296  inline bool
297  operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
298  {
299    return (__lhs.category().equivalent(__lhs.value(), __rhs)
300	    || __rhs.category().equivalent(__lhs, __rhs.value()));
301  }
302
303  inline bool
304  operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
305  {
306    return (__rhs.category().equivalent(__rhs.value(), __lhs)
307	    || __lhs.category().equivalent(__rhs, __lhs.value()));
308  }
309
310  inline bool
311  operator==(const error_condition& __lhs,
312	     const error_condition& __rhs) noexcept
313  {
314    return (__lhs.category() == __rhs.category()
315	    && __lhs.value() == __rhs.value());
316  }
317
318  inline bool
319  operator!=(const error_code& __lhs, const error_code& __rhs) noexcept
320  { return !(__lhs == __rhs); }
321
322  inline bool
323  operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept
324  { return !(__lhs == __rhs); }
325
326  inline bool
327  operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept
328  { return !(__lhs == __rhs); }
329
330  inline bool
331  operator!=(const error_condition& __lhs,
332	     const error_condition& __rhs) noexcept
333  { return !(__lhs == __rhs); }
334
335
336  /**
337   *  @brief Thrown to indicate error code of underlying system.
338   *
339   *  @ingroup exceptions
340   */
341  class system_error : public std::runtime_error
342  {
343  private:
344    error_code 	_M_code;
345
346  public:
347    system_error(error_code __ec = error_code())
348    : runtime_error(__ec.message()), _M_code(__ec) { }
349
350    system_error(error_code __ec, const string& __what)
351    : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { }
352
353    system_error(error_code __ec, const char* __what)
354    : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { }
355
356    system_error(int __v, const error_category& __ecat, const char* __what)
357    : system_error(error_code(__v, __ecat), __what) { }
358
359    system_error(int __v, const error_category& __ecat)
360    : runtime_error(error_code(__v, __ecat).message()),
361      _M_code(__v, __ecat) { }
362
363    system_error(int __v, const error_category& __ecat, const string& __what)
364    : runtime_error(__what + ": " + error_code(__v, __ecat).message()),
365      _M_code(__v, __ecat) { }
366
367    virtual ~system_error() noexcept;
368
369    const error_code&
370    code() const noexcept { return _M_code; }
371  };
372
373_GLIBCXX_END_NAMESPACE_VERSION
374} // namespace
375
376#include <bits/functional_hash.h>
377
378namespace std _GLIBCXX_VISIBILITY(default)
379{
380_GLIBCXX_BEGIN_NAMESPACE_VERSION
381
382#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
383  // DR 1182.
384  /// std::hash specialization for error_code.
385  template<>
386    struct hash<error_code>
387    : public __hash_base<size_t, error_code>
388    {
389      size_t
390      operator()(const error_code& __e) const noexcept
391      {
392	const size_t __tmp = std::_Hash_impl::hash(__e._M_value);
393	return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp);
394      }
395    };
396#endif // _GLIBCXX_COMPATIBILITY_CXX0X
397
398#if __cplusplus > 201402L
399  // DR 2686.
400  /// std::hash specialization for error_condition.
401  template<>
402    struct hash<error_condition>
403    : public __hash_base<size_t, error_condition>
404    {
405      size_t
406      operator()(const error_condition& __e) const noexcept
407      {
408	const size_t __tmp = std::_Hash_impl::hash(__e.value());
409	return std::_Hash_impl::__hash_combine(__e.category(), __tmp);
410      }
411    };
412#endif
413
414_GLIBCXX_END_NAMESPACE_VERSION
415} // namespace
416
417#endif // C++11
418
419#endif // _GLIBCXX_SYSTEM_ERROR
420