libstdc++
system_error
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1 // <system_error> -*- C++ -*-
2 
3 // Copyright (C) 2007-2019 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 
43 namespace 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 #if __cplusplus >= 201103L
368  system_error (const system_error &) = default;
369  system_error &operator= (const system_error &) = default;
370 #endif
371 
372  virtual ~system_error() noexcept;
373 
374  const error_code&
375  code() const noexcept { return _M_code; }
376  };
377 
378 _GLIBCXX_END_NAMESPACE_VERSION
379 } // namespace
380 
381 #include <bits/functional_hash.h>
382 
383 namespace std _GLIBCXX_VISIBILITY(default)
384 {
385 _GLIBCXX_BEGIN_NAMESPACE_VERSION
386 
387 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
388  // DR 1182.
389  /// std::hash specialization for error_code.
390  template<>
391  struct hash<error_code>
392  : public __hash_base<size_t, error_code>
393  {
394  size_t
395  operator()(const error_code& __e) const noexcept
396  {
397  const size_t __tmp = std::_Hash_impl::hash(__e._M_value);
398  return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp);
399  }
400  };
401 #endif // _GLIBCXX_COMPATIBILITY_CXX0X
402 
403 #if __cplusplus > 201402L
404  // DR 2686.
405  /// std::hash specialization for error_condition.
406  template<>
407  struct hash<error_condition>
408  : public __hash_base<size_t, error_condition>
409  {
410  size_t
411  operator()(const error_condition& __e) const noexcept
412  {
413  const size_t __tmp = std::_Hash_impl::hash(__e.value());
414  return std::_Hash_impl::__hash_combine(__e.category(), __tmp);
415  }
416  };
417 #endif
418 
419 _GLIBCXX_END_NAMESPACE_VERSION
420 } // namespace
421 
422 #endif // C++11
423 
424 #endif // _GLIBCXX_SYSTEM_ERROR