libstdc++
system_error
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1 // <system_error> -*- C++ -*-
2 
3 // Copyright (C) 2007-2015 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  inline namespace _V2 {
64 
65  /// error_category
66  class error_category
67  {
68  public:
69  constexpr error_category() noexcept = default;
70 
71  virtual ~error_category();
72 
73  error_category(const error_category&) = delete;
74  error_category& operator=(const error_category&) = delete;
75 
76  virtual const char*
77  name() const noexcept = 0;
78 
79  // We need two different virtual functions here, one returning a
80  // COW string and one returning an SSO string. Their positions in the
81  // vtable must be consistent for dynamic dispatch to work, but which one
82  // the name "message()" finds depends on which ABI the caller is using.
83 #if _GLIBCXX_USE_CXX11_ABI
84  private:
85  _GLIBCXX_DEFAULT_ABI_TAG
86  virtual __cow_string
87  _M_message(int) const;
88 
89  public:
90  _GLIBCXX_DEFAULT_ABI_TAG
91  virtual string
92  message(int) const = 0;
93 #else
94  virtual string
95  message(int) const = 0;
96 
97  private:
98  virtual __sso_string
99  _M_message(int) const;
100 #endif
101 
102  public:
103  virtual error_condition
104  default_error_condition(int __i) const noexcept;
105 
106  virtual bool
107  equivalent(int __i, const error_condition& __cond) const noexcept;
108 
109  virtual bool
110  equivalent(const error_code& __code, int __i) const noexcept;
111 
112  bool
113  operator<(const error_category& __other) const noexcept
114  { return less<const error_category*>()(this, &__other); }
115 
116  bool
117  operator==(const error_category& __other) const noexcept
118  { return this == &__other; }
119 
120  bool
121  operator!=(const error_category& __other) const noexcept
122  { return this != &__other; }
123  };
124 
125  // DR 890.
126  _GLIBCXX_CONST const error_category& system_category() noexcept;
127  _GLIBCXX_CONST const error_category& generic_category() noexcept;
128 
129  } // end inline namespace
130 
131  error_code make_error_code(errc) noexcept;
132 
133  template<typename _Tp>
134  struct hash;
135 
136  /// error_code
137  // Implementation-specific error identification
138  struct error_code
139  {
140  error_code() noexcept
141  : _M_value(0), _M_cat(&system_category()) { }
142 
143  error_code(int __v, const error_category& __cat) noexcept
144  : _M_value(__v), _M_cat(&__cat) { }
145 
146  template<typename _ErrorCodeEnum, typename = typename
147  enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
148  error_code(_ErrorCodeEnum __e) noexcept
149  { *this = make_error_code(__e); }
150 
151  void
152  assign(int __v, const error_category& __cat) noexcept
153  {
154  _M_value = __v;
155  _M_cat = &__cat;
156  }
157 
158  void
159  clear() noexcept
160  { assign(0, system_category()); }
161 
162  // DR 804.
163  template<typename _ErrorCodeEnum>
164  typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value,
165  error_code&>::type
166  operator=(_ErrorCodeEnum __e) noexcept
167  { return *this = make_error_code(__e); }
168 
169  int
170  value() const noexcept { return _M_value; }
171 
172  const error_category&
173  category() const noexcept { return *_M_cat; }
174 
175  error_condition
176  default_error_condition() const noexcept;
177 
178  _GLIBCXX_DEFAULT_ABI_TAG
179  string
180  message() const
181  { return category().message(value()); }
182 
183  explicit operator bool() const noexcept
184  { return _M_value != 0 ? true : false; }
185 
186  // DR 804.
187  private:
188  friend class hash<error_code>;
189 
190  int _M_value;
191  const error_category* _M_cat;
192  };
193 
194  // 19.4.2.6 non-member functions
195  inline error_code
196  make_error_code(errc __e) noexcept
197  { return error_code(static_cast<int>(__e), generic_category()); }
198 
199  inline bool
200  operator<(const error_code& __lhs, const error_code& __rhs) noexcept
201  {
202  return (__lhs.category() < __rhs.category()
203  || (__lhs.category() == __rhs.category()
204  && __lhs.value() < __rhs.value()));
205  }
206 
207  template<typename _CharT, typename _Traits>
208  basic_ostream<_CharT, _Traits>&
209  operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
210  { return (__os << __e.category().name() << ':' << __e.value()); }
211 
212  error_condition make_error_condition(errc) noexcept;
213 
214  /// error_condition
215  // Portable error identification
216  struct error_condition
217  {
218  error_condition() noexcept
219  : _M_value(0), _M_cat(&generic_category()) { }
220 
221  error_condition(int __v, const error_category& __cat) noexcept
222  : _M_value(__v), _M_cat(&__cat) { }
223 
224  template<typename _ErrorConditionEnum, typename = typename
225  enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type>
226  error_condition(_ErrorConditionEnum __e) noexcept
227  { *this = make_error_condition(__e); }
228 
229  void
230  assign(int __v, const error_category& __cat) noexcept
231  {
232  _M_value = __v;
233  _M_cat = &__cat;
234  }
235 
236  // DR 804.
237  template<typename _ErrorConditionEnum>
238  typename enable_if<is_error_condition_enum
239  <_ErrorConditionEnum>::value, error_condition&>::type
240  operator=(_ErrorConditionEnum __e) noexcept
241  { return *this = make_error_condition(__e); }
242 
243  void
244  clear() noexcept
245  { assign(0, generic_category()); }
246 
247  // 19.4.3.4 observers
248  int
249  value() const noexcept { return _M_value; }
250 
251  const error_category&
252  category() const noexcept { return *_M_cat; }
253 
254  _GLIBCXX_DEFAULT_ABI_TAG
255  string
256  message() const
257  { return category().message(value()); }
258 
259  explicit operator bool() const noexcept
260  { return _M_value != 0 ? true : false; }
261 
262  // DR 804.
263  private:
264  int _M_value;
265  const error_category* _M_cat;
266  };
267 
268  // 19.4.3.6 non-member functions
269  inline error_condition
270  make_error_condition(errc __e) noexcept
271  { return error_condition(static_cast<int>(__e), generic_category()); }
272 
273  inline bool
274  operator<(const error_condition& __lhs,
275  const error_condition& __rhs) noexcept
276  {
277  return (__lhs.category() < __rhs.category()
278  || (__lhs.category() == __rhs.category()
279  && __lhs.value() < __rhs.value()));
280  }
281 
282  // 19.4.4 Comparison operators
283  inline bool
284  operator==(const error_code& __lhs, const error_code& __rhs) noexcept
285  { return (__lhs.category() == __rhs.category()
286  && __lhs.value() == __rhs.value()); }
287 
288  inline bool
289  operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
290  {
291  return (__lhs.category().equivalent(__lhs.value(), __rhs)
292  || __rhs.category().equivalent(__lhs, __rhs.value()));
293  }
294 
295  inline bool
296  operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
297  {
298  return (__rhs.category().equivalent(__rhs.value(), __lhs)
299  || __lhs.category().equivalent(__rhs, __lhs.value()));
300  }
301 
302  inline bool
303  operator==(const error_condition& __lhs,
304  const error_condition& __rhs) noexcept
305  {
306  return (__lhs.category() == __rhs.category()
307  && __lhs.value() == __rhs.value());
308  }
309 
310  inline bool
311  operator!=(const error_code& __lhs, const error_code& __rhs) noexcept
312  { return !(__lhs == __rhs); }
313 
314  inline bool
315  operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept
316  { return !(__lhs == __rhs); }
317 
318  inline bool
319  operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept
320  { return !(__lhs == __rhs); }
321 
322  inline bool
323  operator!=(const error_condition& __lhs,
324  const error_condition& __rhs) noexcept
325  { return !(__lhs == __rhs); }
326 
327 
328  /**
329  * @brief Thrown to indicate error code of underlying system.
330  *
331  * @ingroup exceptions
332  */
333  class system_error : public std::runtime_error
334  {
335  private:
336  error_code _M_code;
337 
338  public:
339  system_error(error_code __ec = error_code())
340  : runtime_error(__ec.message()), _M_code(__ec) { }
341 
342  system_error(error_code __ec, const string& __what)
343  : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { }
344 
345  system_error(error_code __ec, const char* __what)
346  : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { }
347 
348  system_error(int __v, const error_category& __ecat, const char* __what)
349  : system_error(error_code(__v, __ecat), __what) { }
350 
351  system_error(int __v, const error_category& __ecat)
352  : runtime_error(error_code(__v, __ecat).message()),
353  _M_code(__v, __ecat) { }
354 
355  system_error(int __v, const error_category& __ecat, const string& __what)
356  : runtime_error(__what + ": " + error_code(__v, __ecat).message()),
357  _M_code(__v, __ecat) { }
358 
359  virtual ~system_error() noexcept;
360 
361  const error_code&
362  code() const noexcept { return _M_code; }
363  };
364 
365 _GLIBCXX_END_NAMESPACE_VERSION
366 } // namespace
367 
368 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
369 
370 #include <bits/functional_hash.h>
371 
372 namespace std _GLIBCXX_VISIBILITY(default)
373 {
374 _GLIBCXX_BEGIN_NAMESPACE_VERSION
375 
376  // DR 1182.
377  /// std::hash specialization for error_code.
378  template<>
379  struct hash<error_code>
380  : public __hash_base<size_t, error_code>
381  {
382  size_t
383  operator()(const error_code& __e) const noexcept
384  {
385  const size_t __tmp = std::_Hash_impl::hash(__e._M_value);
386  return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp);
387  }
388  };
389 
390 _GLIBCXX_END_NAMESPACE_VERSION
391 } // namespace
392 
393 #endif // _GLIBCXX_COMPATIBILITY_CXX0X
394 
395 #endif // C++11
396 
397 #endif // _GLIBCXX_SYSTEM_ERROR