libstdc++-v3/include/std/system_error

   1 // <system_error> -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008, 2009, 2010, 2011 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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
  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   protected:
  69     error_category() noexcept;
  70
  71   public:
  72     virtual ~error_category() noexcept;
  73
  74     error_category(const error_category&) = delete;
  75     error_category& operator=(const error_category&) = delete;
  76
  77     virtual const char*
  78     name() const noexcept = 0;
  79
  80     virtual string
  81     message(int) const = 0;
  82
  83     virtual error_condition
  84     default_error_condition(int __i) const noexcept;
  85
  86     virtual bool
  87     equivalent(int __i, const error_condition& __cond) const noexcept;
  88
  89     virtual bool
  90     equivalent(const error_code& __code, int __i) const noexcept;
  91
  92     bool
  93     operator<(const error_category& __other) const noexcept
  94     { return less<const error_category*>()(this, &__other); }
  95
  96     bool
  97     operator==(const error_category& __other) const noexcept
  98     { return this == &__other; }
  99
 100     bool
 101     operator!=(const error_category& __other) const noexcept
 102     { return this != &__other; }
 103   };
 104
 105   // DR 890.
 106   _GLIBCXX_CONST const error_category& system_category() noexcept;
 107   _GLIBCXX_CONST const error_category& generic_category() noexcept;
 108
 109   error_code make_error_code(errc) noexcept;
 110
 111   template<typename _Tp>
 112     struct hash;
 113
 114   /// error_code
 115   // Implementation-specific error identification
 116   struct error_code
 117   {
 118     error_code() noexcept
 119     : _M_value(0), _M_cat(&system_category()) { }
 120
 121     error_code(int __v, const error_category& __cat) noexcept
 122     : _M_value(__v), _M_cat(&__cat) { }
 123
 124     template<typename _ErrorCodeEnum, typename = typename
 125              enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type>
 126       error_code(_ErrorCodeEnum __e) noexcept
 127       { *this = make_error_code(__e); }
 128
 129     void
 130     assign(int __v, const error_category& __cat) noexcept
 131     {
 132       _M_value = __v;
 133       _M_cat = &__cat;
 134     }
 135
 136     void
 137     clear() noexcept
 138     { assign(0, system_category()); }
 139
 140     // DR 804.
 141     template<typename _ErrorCodeEnum>
 142       typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value,
 143                          error_code&>::type
 144       operator=(_ErrorCodeEnum __e) noexcept
 145       { return *this = make_error_code(__e); }
 146
 147     int
 148     value() const noexcept { return _M_value; }
 149
 150     const error_category&
 151     category() const noexcept { return *_M_cat; }
 152
 153     error_condition
 154     default_error_condition() const noexcept;
 155
 156     string
 157     message() const
 158     { return category().message(value()); }
 159
 160     explicit operator bool() const noexcept
 161     { return _M_value != 0 ? true : false; }
 162
 163     // DR 804.
 164   private:
 165     friend class hash<error_code>;
 166
 167     int                         _M_value;
 168     const error_category*       _M_cat;
 169   };
 170
 171   // 19.4.2.6 non-member functions
 172   inline error_code
 173   make_error_code(errc __e) noexcept
 174   { return error_code(static_cast<int>(__e), generic_category()); }
 175
 176   inline bool
 177   operator<(const error_code& __lhs, const error_code& __rhs) noexcept
 178   {
 179     return (__lhs.category() < __rhs.category()
 180             || (__lhs.category() == __rhs.category()
 181                 && __lhs.value() < __rhs.value()));
 182   }
 183
 184   template<typename _CharT, typename _Traits>
 185     basic_ostream<_CharT, _Traits>&
 186     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
 187     { return (__os << __e.category().name() << ':' << __e.value()); }
 188
 189   error_condition make_error_condition(errc) noexcept;
 190
 191   /// error_condition
 192   // Portable error identification
 193   struct error_condition
 194   {
 195     error_condition() noexcept
 196     : _M_value(0), _M_cat(&generic_category()) { }
 197
 198     error_condition(int __v, const error_category& __cat) noexcept
 199     : _M_value(__v), _M_cat(&__cat) { }
 200
 201     template<typename _ErrorConditionEnum, typename = typename
 202          enable_if<is_error_condition_enum<_ErrorConditionEnum>::value>::type>
 203       error_condition(_ErrorConditionEnum __e) noexcept
 204       { *this = make_error_condition(__e); }
 205
 206     void
 207     assign(int __v, const error_category& __cat) noexcept
 208     {
 209       _M_value = __v;
 210       _M_cat = &__cat;
 211     }
 212
 213     // DR 804.
 214     template<typename _ErrorConditionEnum>
 215       typename enable_if<is_error_condition_enum
 216                          <_ErrorConditionEnum>::value, error_condition&>::type
 217       operator=(_ErrorConditionEnum __e) noexcept
 218       { return *this = make_error_condition(__e); }
 219
 220     void
 221     clear() noexcept
 222     { assign(0, generic_category()); }
 223
 224     // 19.4.3.4 observers
 225     int
 226     value() const noexcept { return _M_value; }
 227
 228     const error_category&
 229     category() const noexcept { return *_M_cat; }
 230
 231     string
 232     message() const
 233     { return category().message(value()); }
 234
 235     explicit operator bool() const noexcept
 236     { return _M_value != 0 ? true : false; }
 237
 238     // DR 804.
 239   private:
 240     int                         _M_value;
 241     const error_category*       _M_cat;
 242   };
 243
 244   // 19.4.3.6 non-member functions
 245   inline error_condition
 246   make_error_condition(errc __e) noexcept
 247   { return error_condition(static_cast<int>(__e), generic_category()); }
 248
 249   inline bool
 250   operator<(const error_condition& __lhs,
 251             const error_condition& __rhs) noexcept
 252   {
 253     return (__lhs.category() < __rhs.category()
 254             || (__lhs.category() == __rhs.category()
 255                 && __lhs.value() < __rhs.value()));
 256   }
 257
 258   // 19.4.4 Comparison operators
 259   inline bool
 260   operator==(const error_code& __lhs, const error_code& __rhs) noexcept
 261   { return (__lhs.category() == __rhs.category()
 262             && __lhs.value() == __rhs.value()); }
 263
 264   inline bool
 265   operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
 266   {
 267     return (__lhs.category().equivalent(__lhs.value(), __rhs)
 268             || __rhs.category().equivalent(__lhs, __rhs.value()));
 269   }
 270
 271   inline bool
 272   operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
 273   {
 274     return (__rhs.category().equivalent(__rhs.value(), __lhs)
 275             || __lhs.category().equivalent(__rhs, __lhs.value()));
 276   }
 277
 278   inline bool
 279   operator==(const error_condition& __lhs,
 280              const error_condition& __rhs) noexcept
 281   {
 282     return (__lhs.category() == __rhs.category()
 283             && __lhs.value() == __rhs.value());
 284   }
 285
 286   inline bool
 287   operator!=(const error_code& __lhs, const error_code& __rhs) noexcept
 288   { return !(__lhs == __rhs); }
 289
 290   inline bool
 291   operator!=(const error_code& __lhs, const error_condition& __rhs) noexcept
 292   { return !(__lhs == __rhs); }
 293
 294   inline bool
 295   operator!=(const error_condition& __lhs, const error_code& __rhs) noexcept
 296   { return !(__lhs == __rhs); }
 297
 298   inline bool
 299   operator!=(const error_condition& __lhs,
 300              const error_condition& __rhs) noexcept
 301   { return !(__lhs == __rhs); }
 302
 303
 304   /**
 305    *  @brief Thrown to indicate error code of underlying system.
 306    *
 307    *  @ingroup exceptions
 308    */
 309   class system_error : public std::runtime_error
 310   {
 311   private:
 312     error_code  _M_code;
 313
 314   public:
 315     system_error(error_code __ec = error_code())
 316     : runtime_error(__ec.message()), _M_code(__ec) { }
 317
 318     system_error(error_code __ec, const string& __what)
 319     : runtime_error(__what + ": " + __ec.message()), _M_code(__ec) { }
 320
 321     /*
 322      * TODO: Add const char* ctors to all exceptions.
 323      *
 324      * system_error(error_code __ec, const char* __what)
 325      * : runtime_error(__what + (": " + __ec.message())), _M_code(__ec) { }
 326      *
 327      * system_error(int __v, const error_category& __ecat, const char* __what)
 328      * : runtime_error(__what + (": " + __ec.message())),
 329      *   _M_code(error_code(__v, __ecat)) { }
 330      */
 331
 332     system_error(int __v, const error_category& __ecat)
 333     : runtime_error(error_code(__v, __ecat).message()),
 334       _M_code(__v, __ecat) { }
 335
 336     system_error(int __v, const error_category& __ecat, const string& __what)
 337     : runtime_error(__what + ": " + error_code(__v, __ecat).message()),
 338       _M_code(__v, __ecat) { }
 339
 340     virtual ~system_error() noexcept;
 341
 342     const error_code&
 343     code() const noexcept { return _M_code; }
 344   };
 345
 346 _GLIBCXX_END_NAMESPACE_VERSION
 347 } // namespace
 348
 349 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
 350
 351 #include <bits/functional_hash.h>
 352
 353 namespace std _GLIBCXX_VISIBILITY(default)
 354 {
 355 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 356
 357   // DR 1182.
 358   /// std::hash specialization for error_code.
 359   template<>
 360     struct hash<error_code>
 361     : public __hash_base<size_t, error_code>
 362     {
 363       size_t
 364       operator()(const error_code& __e) const noexcept
 365       {
 366         const size_t __tmp = std::_Hash_impl::hash(__e._M_value);
 367         return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp);
 368       }
 369     };
 370
 371 _GLIBCXX_END_NAMESPACE_VERSION
 372 } // namespace
 373
 374 #endif // _GLIBCXX_COMPATIBILITY_CXX0X
 375
 376 #endif // __GXX_EXPERIMENTAL_CXX0X__
 377
 378 #endif // _GLIBCXX_SYSTEM_ERROR