1 | // <system_error> -*- C++ -*- |
2 | |
3 | // Copyright (C) 2007-2021 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 | #if __cplusplus > 201703L |
43 | # include <compare> |
44 | #endif |
45 | |
46 | namespace std _GLIBCXX_VISIBILITY(default) |
47 | { |
48 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
49 | |
50 | /** @addtogroup diagnostics |
51 | * @{ |
52 | */ |
53 | |
54 | class error_code; |
55 | class error_condition; |
56 | class system_error; |
57 | |
58 | /// is_error_code_enum |
59 | template<typename _Tp> |
60 | struct is_error_code_enum : public false_type { }; |
61 | |
62 | /// is_error_condition_enum |
63 | template<typename _Tp> |
64 | struct is_error_condition_enum : public false_type { }; |
65 | |
66 | template<> |
67 | struct is_error_condition_enum<errc> |
68 | : public true_type { }; |
69 | |
70 | #if __cplusplus > 201402L |
71 | template <typename _Tp> |
72 | inline constexpr bool is_error_code_enum_v = |
73 | is_error_code_enum<_Tp>::value; |
74 | template <typename _Tp> |
75 | inline constexpr bool is_error_condition_enum_v = |
76 | is_error_condition_enum<_Tp>::value; |
77 | #endif // C++17 |
78 | /// @} |
79 | |
80 | inline namespace _V2 { |
81 | |
82 | /** @addtogroup diagnostics |
83 | * @{ |
84 | */ |
85 | |
86 | /** Abstract base class for types defining a category of error codes. |
87 | * |
88 | * An error category defines a context that give meaning to the integer |
89 | * stored in an `error_code` or `error_condition` object. For example, |
90 | * the standard `errno` constants such a `EINVAL` and `ENOMEM` are |
91 | * associated with the "generic" category and other OS-specific error |
92 | * numbers are associated with the "system" category, but a user-defined |
93 | * category might give different meanings to the same numerical values. |
94 | * |
95 | * @since C++11 |
96 | */ |
97 | class error_category |
98 | { |
99 | public: |
100 | constexpr error_category() noexcept = default; |
101 | |
102 | virtual ~error_category(); |
103 | |
104 | error_category(const error_category&) = delete; |
105 | error_category& operator=(const error_category&) = delete; |
106 | |
107 | virtual const char* |
108 | name() const noexcept = 0; |
109 | |
110 | // We need two different virtual functions here, one returning a |
111 | // COW string and one returning an SSO string. Their positions in the |
112 | // vtable must be consistent for dynamic dispatch to work, but which one |
113 | // the name "message()" finds depends on which ABI the caller is using. |
114 | #if _GLIBCXX_USE_CXX11_ABI |
115 | private: |
116 | _GLIBCXX_DEFAULT_ABI_TAG |
117 | virtual __cow_string |
118 | _M_message(int) const; |
119 | |
120 | public: |
121 | _GLIBCXX_DEFAULT_ABI_TAG |
122 | virtual string |
123 | message(int) const = 0; |
124 | #else |
125 | virtual string |
126 | message(int) const = 0; |
127 | |
128 | private: |
129 | virtual __sso_string |
130 | _M_message(int) const; |
131 | #endif |
132 | |
133 | public: |
134 | virtual error_condition |
135 | default_error_condition(int __i) const noexcept; |
136 | |
137 | virtual bool |
138 | equivalent(int __i, const error_condition& __cond) const noexcept; |
139 | |
140 | virtual bool |
141 | equivalent(const error_code& __code, int __i) const noexcept; |
142 | |
143 | bool |
144 | operator==(const error_category& __other) const noexcept |
145 | { return this == &__other; } |
146 | |
147 | #if __cpp_lib_three_way_comparison |
148 | strong_ordering |
149 | operator<=>(const error_category& __rhs) const noexcept |
150 | { return std::compare_three_way()(this, &__rhs); } |
151 | #else |
152 | bool |
153 | operator!=(const error_category& __other) const noexcept |
154 | { return this != &__other; } |
155 | |
156 | bool |
157 | operator<(const error_category& __other) const noexcept |
158 | { return less<const error_category*>()(this, &__other); } |
159 | #endif |
160 | }; |
161 | |
162 | // DR 890. |
163 | |
164 | /// Error category for `errno` error codes. |
165 | _GLIBCXX_CONST const error_category& generic_category() noexcept; |
166 | |
167 | /// Error category for other error codes defined by the OS. |
168 | _GLIBCXX_CONST const error_category& system_category() noexcept; |
169 | |
170 | /// @} |
171 | } // end inline namespace |
172 | |
173 | /** @addtogroup diagnostics |
174 | * @{ |
175 | */ |
176 | |
177 | error_code make_error_code(errc) noexcept; |
178 | |
179 | /** Class error_code |
180 | * |
181 | * This class is a value type storing an integer error number and a |
182 | * category that gives meaning to the error number. Typically this is done |
183 | * close the the point where the error happens, to capture the original |
184 | * error value. |
185 | * |
186 | * An `error_code` object can be used to store the original error value |
187 | * emitted by some subsystem, with a category relevant to the subsystem. |
188 | * For example, errors from POSIX library functions can be represented by |
189 | * an `errno` value and the "generic" category, but errors from an HTTP |
190 | * library might be represented by an HTTP response status code (e.g. 404) |
191 | * and a custom category defined by the library. |
192 | * |
193 | * @since C++11 |
194 | * @ingroup diagnostics |
195 | */ |
196 | class error_code |
197 | { |
198 | public: |
199 | error_code() noexcept |
200 | : _M_value(0), _M_cat(&system_category()) { } |
201 | |
202 | error_code(int __v, const error_category& __cat) noexcept |
203 | : _M_value(__v), _M_cat(&__cat) { } |
204 | |
205 | template<typename _ErrorCodeEnum, typename = typename |
206 | enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type> |
207 | error_code(_ErrorCodeEnum __e) noexcept |
208 | { *this = make_error_code(__e); } |
209 | |
210 | void |
211 | assign(int __v, const error_category& __cat) noexcept |
212 | { |
213 | _M_value = __v; |
214 | _M_cat = &__cat; |
215 | } |
216 | |
217 | void |
218 | clear() noexcept |
219 | { assign(v: 0, cat: system_category()); } |
220 | |
221 | // DR 804. |
222 | template<typename _ErrorCodeEnum> |
223 | typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value, |
224 | error_code&>::type |
225 | operator=(_ErrorCodeEnum __e) noexcept |
226 | { return *this = make_error_code(__e); } |
227 | |
228 | int |
229 | value() const noexcept { return _M_value; } |
230 | |
231 | const error_category& |
232 | category() const noexcept { return *_M_cat; } |
233 | |
234 | error_condition |
235 | default_error_condition() const noexcept; |
236 | |
237 | _GLIBCXX_DEFAULT_ABI_TAG |
238 | string |
239 | message() const |
240 | { return category().message(value()); } |
241 | |
242 | explicit operator bool() const noexcept |
243 | { return _M_value != 0; } |
244 | |
245 | // DR 804. |
246 | private: |
247 | int _M_value; |
248 | const error_category* _M_cat; |
249 | }; |
250 | |
251 | // 19.4.2.6 non-member functions |
252 | |
253 | /// @relates error_code @{ |
254 | |
255 | inline error_code |
256 | make_error_code(errc __e) noexcept |
257 | { return error_code(static_cast<int>(__e), generic_category()); } |
258 | |
259 | #if __cpp_lib_three_way_comparison |
260 | inline strong_ordering |
261 | operator<=>(const error_code& __lhs, const error_code& __rhs) noexcept |
262 | { |
263 | if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0) |
264 | return __c; |
265 | return __lhs.value() <=> __rhs.value(); |
266 | } |
267 | #else |
268 | inline bool |
269 | operator<(const error_code& __lhs, const error_code& __rhs) noexcept |
270 | { |
271 | return (__lhs.category() < __rhs.category() |
272 | || (__lhs.category() == __rhs.category() |
273 | && __lhs.value() < __rhs.value())); |
274 | } |
275 | #endif |
276 | |
277 | template<typename _CharT, typename _Traits> |
278 | basic_ostream<_CharT, _Traits>& |
279 | operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e) |
280 | { return (__os << __e.category().name() << ':' << __e.value()); } |
281 | |
282 | /// @} |
283 | |
284 | error_condition make_error_condition(errc) noexcept; |
285 | |
286 | /** Class error_condition |
287 | * |
288 | * This class represents error conditions that may be visible at an API |
289 | * boundary. Different `error_code` values that can occur within a library |
290 | * or module might map to the same `error_condition`. |
291 | * |
292 | * An `error_condition` represents something that the program can test for, |
293 | * and subsequently take appropriate action. |
294 | * |
295 | * @since C++11 |
296 | */ |
297 | class error_condition |
298 | { |
299 | public: |
300 | error_condition() noexcept |
301 | : _M_value(0), _M_cat(&generic_category()) { } |
302 | |
303 | error_condition(int __v, const error_category& __cat) noexcept |
304 | : _M_value(__v), _M_cat(&__cat) { } |
305 | |
306 | template<typename _ErrorConditionEnum, typename = typename |
307 | enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type> |
308 | error_condition(_ErrorConditionEnum __e) noexcept |
309 | { *this = make_error_condition(__e); } |
310 | |
311 | void |
312 | assign(int __v, const error_category& __cat) noexcept |
313 | { |
314 | _M_value = __v; |
315 | _M_cat = &__cat; |
316 | } |
317 | |
318 | // DR 804. |
319 | template<typename _ErrorConditionEnum> |
320 | typename enable_if<is_error_condition_enum |
321 | <_ErrorConditionEnum>::value, error_condition&>::type |
322 | operator=(_ErrorConditionEnum __e) noexcept |
323 | { return *this = make_error_condition(__e); } |
324 | |
325 | void |
326 | clear() noexcept |
327 | { assign(v: 0, cat: generic_category()); } |
328 | |
329 | // 19.4.3.4 observers |
330 | int |
331 | value() const noexcept { return _M_value; } |
332 | |
333 | const error_category& |
334 | category() const noexcept { return *_M_cat; } |
335 | |
336 | _GLIBCXX_DEFAULT_ABI_TAG |
337 | string |
338 | message() const |
339 | { return category().message(value()); } |
340 | |
341 | explicit operator bool() const noexcept |
342 | { return _M_value != 0; } |
343 | |
344 | // DR 804. |
345 | private: |
346 | int _M_value; |
347 | const error_category* _M_cat; |
348 | }; |
349 | |
350 | // 19.4.3.6 non-member functions |
351 | |
352 | /// Create an `error_condition` representing a standard `errc` condition. |
353 | /// @relates error_condition |
354 | inline error_condition |
355 | make_error_condition(errc __e) noexcept |
356 | { return error_condition(static_cast<int>(__e), generic_category()); } |
357 | |
358 | // 19.4.4 Comparison operators |
359 | |
360 | /// @relates error_code |
361 | inline bool |
362 | operator==(const error_code& __lhs, const error_code& __rhs) noexcept |
363 | { return (__lhs.category() == __rhs.category() |
364 | && __lhs.value() == __rhs.value()); } |
365 | |
366 | /// @relates error_code |
367 | inline bool |
368 | operator==(const error_code& __lhs, const error_condition& __rhs) noexcept |
369 | { |
370 | return (__lhs.category().equivalent(i: __lhs.value(), cond: __rhs) |
371 | || __rhs.category().equivalent(code: __lhs, i: __rhs.value())); |
372 | } |
373 | |
374 | /// @relates error_condition |
375 | inline bool |
376 | operator==(const error_condition& __lhs, |
377 | const error_condition& __rhs) noexcept |
378 | { |
379 | return (__lhs.category() == __rhs.category() |
380 | && __lhs.value() == __rhs.value()); |
381 | } |
382 | |
383 | #if __cpp_lib_three_way_comparison |
384 | /// Define an ordering for error_condition objects. |
385 | /// @relates error_condition |
386 | inline strong_ordering |
387 | operator<=>(const error_condition& __lhs, |
388 | const error_condition& __rhs) noexcept |
389 | { |
390 | if (auto __c = __lhs.category() <=> __rhs.category(); __c != 0) |
391 | return __c; |
392 | return __lhs.value() <=> __rhs.value(); |
393 | } |
394 | #else |
395 | /// Define an ordering for error_condition objects. |
396 | /// @relates error_condition |
397 | inline bool |
398 | operator<(const error_condition& __lhs, |
399 | const error_condition& __rhs) noexcept |
400 | { |
401 | return (__lhs.category() < __rhs.category() |
402 | || (__lhs.category() == __rhs.category() |
403 | && __lhs.value() < __rhs.value())); |
404 | } |
405 | |
406 | /// @relates error_condition |
407 | inline bool |
408 | operator==(const error_condition& __lhs, const error_code& __rhs) noexcept |
409 | { |
410 | return (__rhs.category().equivalent(i: __rhs.value(), cond: __lhs) |
411 | || __lhs.category().equivalent(code: __rhs, i: __lhs.value())); |
412 | } |
413 | |
414 | /// @relates error_code |
415 | inline bool |
416 | operator!=(const error_code& __lhs, const error_code& __rhs) noexcept |
417 | { return !(__lhs == __rhs); } |
418 | |
419 | /// @relates error_code |
420 | inline bool |
421 | operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept |
422 | { return !(__lhs == __rhs); } |
423 | |
424 | /// @relates error_condition |
425 | inline bool |
426 | operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept |
427 | { return !(__lhs == __rhs); } |
428 | |
429 | /// @relates error_condition |
430 | inline bool |
431 | operator!=(const error_condition& __lhs, |
432 | const error_condition& __rhs) noexcept |
433 | { return !(__lhs == __rhs); } |
434 | #endif // three_way_comparison |
435 | /// @} |
436 | |
437 | /** |
438 | * @brief An exception type that includes an `error_code` value. |
439 | * |
440 | * Typically used to report errors from the operating system and other |
441 | * low-level APIs. |
442 | * |
443 | * @since C++11 |
444 | * @ingroup exceptions |
445 | */ |
446 | class system_error : public std::runtime_error |
447 | { |
448 | private: |
449 | error_code _M_code; |
450 | |
451 | public: |
452 | system_error(error_code __ec = error_code()) |
453 | : runtime_error(__ec.message()), _M_code(__ec) { } |
454 | |
455 | system_error(error_code __ec, const string& __what) |
456 | : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { } |
457 | |
458 | system_error(error_code __ec, const char* __what) |
459 | : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { } |
460 | |
461 | system_error(int __v, const error_category& __ecat, const char* __what) |
462 | : system_error(error_code(__v, __ecat), __what) { } |
463 | |
464 | system_error(int __v, const error_category& __ecat) |
465 | : runtime_error(error_code(__v, __ecat).message()), |
466 | _M_code(__v, __ecat) { } |
467 | |
468 | system_error(int __v, const error_category& __ecat, const string& __what) |
469 | : runtime_error(__what + ": " + error_code(__v, __ecat).message()), |
470 | _M_code(__v, __ecat) { } |
471 | |
472 | #if __cplusplus >= 201103L |
473 | system_error (const system_error &) = default; |
474 | system_error &operator= (const system_error &) = default; |
475 | #endif |
476 | |
477 | virtual ~system_error() noexcept; |
478 | |
479 | const error_code& |
480 | code() const noexcept { return _M_code; } |
481 | }; |
482 | |
483 | _GLIBCXX_END_NAMESPACE_VERSION |
484 | } // namespace |
485 | |
486 | #include <bits/functional_hash.h> |
487 | |
488 | namespace std _GLIBCXX_VISIBILITY(default) |
489 | { |
490 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
491 | |
492 | #ifndef _GLIBCXX_COMPATIBILITY_CXX0X |
493 | // DR 1182. |
494 | /// std::hash specialization for error_code. |
495 | /// @relates error_code |
496 | template<> |
497 | struct hash<error_code> |
498 | : public __hash_base<size_t, error_code> |
499 | { |
500 | size_t |
501 | operator()(const error_code& __e) const noexcept |
502 | { |
503 | const size_t __tmp = std::_Hash_impl::hash(val: __e.value()); |
504 | return std::_Hash_impl::__hash_combine(val: &__e.category(), hash: __tmp); |
505 | } |
506 | }; |
507 | #endif // _GLIBCXX_COMPATIBILITY_CXX0X |
508 | |
509 | #if __cplusplus >= 201703L |
510 | // DR 2686. |
511 | /// std::hash specialization for error_condition. |
512 | /// @relates error_condition |
513 | template<> |
514 | struct hash<error_condition> |
515 | : public __hash_base<size_t, error_condition> |
516 | { |
517 | size_t |
518 | operator()(const error_condition& __e) const noexcept |
519 | { |
520 | const size_t __tmp = std::_Hash_impl::hash(val: __e.value()); |
521 | return std::_Hash_impl::__hash_combine(val: &__e.category(), hash: __tmp); |
522 | } |
523 | }; |
524 | #endif |
525 | |
526 | _GLIBCXX_END_NAMESPACE_VERSION |
527 | } // namespace |
528 | |
529 | #endif // C++11 |
530 | |
531 | #endif // _GLIBCXX_SYSTEM_ERROR |
532 | |