libstdc++
system_error
1 // <system_error> -*- C++ -*-
2 
3 // Copyright (C) 2007-2014 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 error_category;
50  class system_error;
51 
52  /// is_error_code_enum
53  template<typename _Tp>
54  struct is_error_code_enum : public false_type { };
55 
56  /// is_error_condition_enum
57  template<typename _Tp>
58  struct is_error_condition_enum : public false_type { };
59 
60  template<>
61  struct is_error_condition_enum<errc>
62  : public true_type { };
63 
64 
65  /// error_category
66  class error_category
67  {
68  public:
69 #ifdef _GLIBCXX_COMPATIBILITY_CXX0X
70  error_category() noexcept;
71 #else
72  constexpr error_category() noexcept = default;
73 #endif
74 
75  virtual ~error_category();
76 
77  error_category(const error_category&) = delete;
78  error_category& operator=(const error_category&) = delete;
79 
80  virtual const char*
81  name() const noexcept = 0;
82 
83  virtual string
84  message(int) const = 0;
85 
86  virtual error_condition
87  default_error_condition(int __i) const noexcept;
88 
89  virtual bool
90  equivalent(int __i, const error_condition& __cond) const noexcept;
91 
92  virtual bool
93  equivalent(const error_code& __code, int __i) const noexcept;
94 
95  bool
96  operator<(const error_category& __other) const noexcept
97  { return less<const error_category*>()(this, &__other); }
98 
99  bool
100  operator==(const error_category& __other) const noexcept
101  { return this == &__other; }
102 
103  bool
104  operator!=(const error_category& __other) const noexcept
105  { return this != &__other; }
106  };
107 
108  // DR 890.
109  _GLIBCXX_CONST const error_category& system_category() noexcept;
110  _GLIBCXX_CONST const error_category& generic_category() noexcept;
111 
112  error_code make_error_code(errc) noexcept;
113 
114  template<typename _Tp>
115  struct hash;
116 
117  /// error_code
118  // Implementation-specific error identification
119  struct error_code
120  {
121  error_code() noexcept
122  : _M_value(0), _M_cat(&system_category()) { }
123 
124  error_code(int __v, const error_category& __cat) noexcept
125  : _M_value(__v), _M_cat(&__cat) { }
126 
127  template<typename _ErrorCodeEnum, typename = typename
128  enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
129  error_code(_ErrorCodeEnum __e) noexcept
130  { *this = make_error_code(__e); }
131 
132  void
133  assign(int __v, const error_category& __cat) noexcept
134  {
135  _M_value = __v;
136  _M_cat = &__cat;
137  }
138 
139  void
140  clear() noexcept
141  { assign(0, system_category()); }
142 
143  // DR 804.
144  template<typename _ErrorCodeEnum>
145  typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value,
146  error_code&>::type
147  operator=(_ErrorCodeEnum __e) noexcept
148  { return *this = make_error_code(__e); }
149 
150  int
151  value() const noexcept { return _M_value; }
152 
153  const error_category&
154  category() const noexcept { return *_M_cat; }
155 
156  error_condition
157  default_error_condition() const noexcept;
158 
159  string
160  message() const
161  { return category().message(value()); }
162 
163  explicit operator bool() const noexcept
164  { return _M_value != 0 ? true : false; }
165 
166  // DR 804.
167  private:
168  friend class hash<error_code>;
169 
170  int _M_value;
171  const error_category* _M_cat;
172  };
173 
174  // 19.4.2.6 non-member functions
175  inline error_code
176  make_error_code(errc __e) noexcept
177  { return error_code(static_cast<int>(__e), generic_category()); }
178 
179  inline bool
180  operator<(const error_code& __lhs, const error_code& __rhs) noexcept
181  {
182  return (__lhs.category() < __rhs.category()
183  || (__lhs.category() == __rhs.category()
184  && __lhs.value() < __rhs.value()));
185  }
186 
187  template<typename _CharT, typename _Traits>
188  basic_ostream<_CharT, _Traits>&
189  operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
190  { return (__os << __e.category().name() << ':' << __e.value()); }
191 
192  error_condition make_error_condition(errc) noexcept;
193 
194  /// error_condition
195  // Portable error identification
196  struct error_condition
197  {
198  error_condition() noexcept
199  : _M_value(0), _M_cat(&generic_category()) { }
200 
201  error_condition(int __v, const error_category& __cat) noexcept
202  : _M_value(__v), _M_cat(&__cat) { }
203 
204  template<typename _ErrorConditionEnum, typename = typename
205  enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type>
206  error_condition(_ErrorConditionEnum __e) noexcept
207  { *this = make_error_condition(__e); }
208 
209  void
210  assign(int __v, const error_category& __cat) noexcept
211  {
212  _M_value = __v;
213  _M_cat = &__cat;
214  }
215 
216  // DR 804.
217  template<typename _ErrorConditionEnum>
218  typename enable_if<is_error_condition_enum
219  <_ErrorConditionEnum>::value, error_condition&>::type
220  operator=(_ErrorConditionEnum __e) noexcept
221  { return *this = make_error_condition(__e); }
222 
223  void
224  clear() noexcept
225  { assign(0, generic_category()); }
226 
227  // 19.4.3.4 observers
228  int
229  value() const noexcept { return _M_value; }
230 
231  const error_category&
232  category() const noexcept { return *_M_cat; }
233 
234  string
235  message() const
236  { return category().message(value()); }
237 
238  explicit operator bool() const noexcept
239  { return _M_value != 0 ? true : false; }
240 
241  // DR 804.
242  private:
243  int _M_value;
244  const error_category* _M_cat;
245  };
246 
247  // 19.4.3.6 non-member functions
248  inline error_condition
249  make_error_condition(errc __e) noexcept
250  { return error_condition(static_cast<int>(__e), generic_category()); }
251 
252  inline bool
253  operator<(const error_condition& __lhs,
254  const error_condition& __rhs) noexcept
255  {
256  return (__lhs.category() < __rhs.category()
257  || (__lhs.category() == __rhs.category()
258  && __lhs.value() < __rhs.value()));
259  }
260 
261  // 19.4.4 Comparison operators
262  inline bool
263  operator==(const error_code& __lhs, const error_code& __rhs) noexcept
264  { return (__lhs.category() == __rhs.category()
265  && __lhs.value() == __rhs.value()); }
266 
267  inline bool
268  operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
269  {
270  return (__lhs.category().equivalent(__lhs.value(), __rhs)
271  || __rhs.category().equivalent(__lhs, __rhs.value()));
272  }
273 
274  inline bool
275  operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
276  {
277  return (__rhs.category().equivalent(__rhs.value(), __lhs)
278  || __lhs.category().equivalent(__rhs, __lhs.value()));
279  }
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.value() == __rhs.value());
287  }
288 
289  inline bool
290  operator!=(const error_code& __lhs, const error_code& __rhs) noexcept
291  { return !(__lhs == __rhs); }
292 
293  inline bool
294  operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept
295  { return !(__lhs == __rhs); }
296 
297  inline bool
298  operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept
299  { return !(__lhs == __rhs); }
300 
301  inline bool
302  operator!=(const error_condition& __lhs,
303  const error_condition& __rhs) noexcept
304  { return !(__lhs == __rhs); }
305 
306 
307  /**
308  * @brief Thrown to indicate error code of underlying system.
309  *
310  * @ingroup exceptions
311  */
312  class system_error : public std::runtime_error
313  {
314  private:
315  error_code _M_code;
316 
317  public:
318  system_error(error_code __ec = error_code())
319  : runtime_error(__ec.message()), _M_code(__ec) { }
320 
321  system_error(error_code __ec, const string& __what)
322  : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { }
323 
324  /*
325  * TODO: Add const char* ctors to all exceptions.
326  *
327  * system_error(error_code __ec, const char* __what)
328  * : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { }
329  *
330  * system_error(int __v, const error_category& __ecat, const char* __what)
331  * : runtime_error(__what + (": " + __ec.message())),
332  * _M_code(error_code(__v, __ecat)) { }
333  */
334 
335  system_error(int __v, const error_category& __ecat)
336  : runtime_error(error_code(__v, __ecat).message()),
337  _M_code(__v, __ecat) { }
338 
339  system_error(int __v, const error_category& __ecat, const string& __what)
340  : runtime_error(__what + ": " + error_code(__v, __ecat).message()),
341  _M_code(__v, __ecat) { }
342 
343  virtual ~system_error() noexcept;
344 
345  const error_code&
346  code() const noexcept { return _M_code; }
347  };
348 
349 _GLIBCXX_END_NAMESPACE_VERSION
350 } // namespace
351 
352 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
353 
354 #include <bits/functional_hash.h>
355 
356 namespace std _GLIBCXX_VISIBILITY(default)
357 {
358 _GLIBCXX_BEGIN_NAMESPACE_VERSION
359 
360  // DR 1182.
361  /// std::hash specialization for error_code.
362  template<>
363  struct hash<error_code>
364  : public __hash_base<size_t, error_code>
365  {
366  size_t
367  operator()(const error_code& __e) const noexcept
368  {
369  const size_t __tmp = std::_Hash_impl::hash(__e._M_value);
370  return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp);
371  }
372  };
373 
374 _GLIBCXX_END_NAMESPACE_VERSION
375 } // namespace
376 
377 #endif // _GLIBCXX_COMPATIBILITY_CXX0X
378 
379 #endif // C++11
380 
381 #endif // _GLIBCXX_SYSTEM_ERROR