Line data Source code
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 1688 : operator==(const error_category& __other) const noexcept
145 1688 : { 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 172788 : error_code() noexcept
200 172788 : : _M_value(0), _M_cat(&system_category()) { }
201 :
202 29648 : error_code(int __v, const error_category& __cat) noexcept
203 29648 : : _M_value(__v), _M_cat(&__cat) { }
204 :
205 : template<typename _ErrorCodeEnum, typename = typename
206 : enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
207 1688 : error_code(_ErrorCodeEnum __e) noexcept
208 1688 : { *this = make_error_code(__e); }
209 :
210 : void
211 727 : assign(int __v, const error_category& __cat) noexcept
212 : {
213 727 : _M_value = __v;
214 727 : _M_cat = &__cat;
215 727 : }
216 :
217 : void
218 485 : clear() noexcept
219 485 : { assign(0, 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 27255 : operator=(_ErrorCodeEnum __e) noexcept
226 27255 : { return *this = make_error_code(__e); }
227 :
228 : int
229 314 : value() const noexcept { return _M_value; }
230 :
231 : const error_category&
232 3624 : 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 6 : message() const
240 6 : { return category().message(value()); }
241 :
242 99013 : explicit operator bool() const noexcept
243 99013 : { 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 0 : make_error_code(errc __e) noexcept
257 0 : { 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(0, 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 1688 : operator==(const error_code& __lhs, const error_code& __rhs) noexcept
363 1688 : { return (__lhs.category() == __rhs.category()
364 1688 : && __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(__lhs.value(), __rhs)
371 : || __rhs.category().equivalent(__lhs, __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(__rhs.value(), __lhs)
411 : || __lhs.category().equivalent(__rhs, __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 0 : system_error(error_code __ec = error_code())
453 0 : : 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 0 : system_error(error_code __ec, const char* __what)
459 0 : : 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 0 : 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(__e.value());
504 : return std::_Hash_impl::__hash_combine(&__e.category(), __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(__e.value());
521 : return std::_Hash_impl::__hash_combine(&__e.category(), __tmp);
522 : }
523 : };
524 : #endif
525 :
526 : _GLIBCXX_END_NAMESPACE_VERSION
527 : } // namespace
528 :
529 : #endif // C++11
530 :
531 : #endif // _GLIBCXX_SYSTEM_ERROR
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