libstdc++-v3/include/std/system_error

   1 // <system_error> -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008, 2009, 2010 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 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 _GLIBCXX_BEGIN_NAMESPACE(std)
  44
  45   class error_code;
  46   class error_condition;
  47   class error_category;
  48   class system_error;
  49
  50   /// is_error_code_enum
  51   template<typename _Tp>
  52     struct is_error_code_enum : public false_type { };
  53
  54   /// is_error_condition_enum
  55   template<typename _Tp>
  56     struct is_error_condition_enum : public false_type { };
  57
  58   template<>
  59     struct is_error_condition_enum<errc>
  60     : public true_type { };
  61
  62
  63   /// error_category
  64   class error_category
  65   {
  66   protected:
  67     error_category();
  68
  69   public:
  70     virtual ~error_category() { }
  71
  72     error_category(const error_category&) = delete;
  73     error_category& operator=(const error_category&) = delete;
  74
  75     virtual const char*
  76     name() const = 0;
  77
  78     virtual string
  79     message(int) const = 0;
  80
  81     virtual error_condition
  82     default_error_condition(int __i) const;
  83
  84     virtual bool
  85     equivalent(int __i, const error_condition& __cond) const;
  86
  87     virtual bool
  88     equivalent(const error_code& __code, int __i) const;
  89
  90     bool
  91     operator<(const error_category& __other) const
  92     { return less<const error_category*>()(this, &__other); }
  93
  94     bool
  95     operator==(const error_category& __other) const
  96     { return this == &__other; }
  97
  98     bool
  99     operator!=(const error_category& __other) const
 100     { return this != &__other; }
 101   };
 102
 103   inline error_category::error_category() = default;
 104
 105   // DR 890.
 106   _GLIBCXX_CONST const error_category& system_category() throw();
 107   _GLIBCXX_CONST const error_category& generic_category() throw();
 108
 109   error_code make_error_code(errc);
 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()
 119     : _M_value(0), _M_cat(&system_category()) { }
 120
 121     error_code(int __v, const error_category& __cat)
 122     : _M_value(__v), _M_cat(&__cat) { }
 123
 124     template<typename _ErrorCodeEnum>
 125       error_code(_ErrorCodeEnum __e,
 126       typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type* = 0)
 127       { *this = make_error_code(__e); }
 128
 129     void
 130     assign(int __v, const error_category& __cat)
 131     {
 132       _M_value = __v;
 133       _M_cat = &__cat;
 134     }
 135
 136     void
 137     clear()
 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)
 145       { return *this = make_error_code(__e); }
 146
 147     int
 148     value() const { return _M_value; }
 149
 150     const error_category&
 151     category() const { return *_M_cat; }
 152
 153     error_condition
 154     default_error_condition() const;
 155
 156     string
 157     message() const
 158     { return category().message(value()); }
 159
 160     explicit operator bool() const
 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)
 174   { return error_code(static_cast<int>(__e), generic_category()); }
 175
 176   inline bool
 177   operator<(const error_code& __lhs, const error_code& __rhs)
 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);
 190
 191   /// error_condition
 192   // Portable error identification
 193   struct error_condition
 194   {
 195     error_condition()
 196     : _M_value(0), _M_cat(&generic_category()) { }
 197
 198     error_condition(int __v, const error_category& __cat)
 199     : _M_value(__v), _M_cat(&__cat) { }
 200
 201     template<typename _ErrorConditionEnum>
 202       error_condition(_ErrorConditionEnum __e,
 203                       typename enable_if<is_error_condition_enum
 204                                       <_ErrorConditionEnum>::value>::type* = 0)
 205       { *this = make_error_condition(__e); }
 206
 207     void
 208     assign(int __v, const error_category& __cat)
 209     {
 210       _M_value = __v;
 211       _M_cat = &__cat;
 212     }
 213
 214     // DR 804.
 215     template<typename _ErrorConditionEnum>
 216       typename enable_if<is_error_condition_enum
 217                          <_ErrorConditionEnum>::value, error_condition&>::type
 218       operator=(_ErrorConditionEnum __e)
 219       { return *this = make_error_condition(__e); }
 220
 221     void
 222     clear()
 223     { assign(0, generic_category()); }
 224
 225     // 19.4.3.4 observers
 226     int
 227     value() const { return _M_value; }
 228
 229     const error_category&
 230     category() const { return *_M_cat; }
 231
 232     string
 233     message() const
 234     { return category().message(value()); }
 235
 236     explicit operator bool() const
 237     { return _M_value != 0 ? true : false; }
 238
 239     // DR 804.
 240   private:
 241     int                         _M_value;
 242     const error_category*       _M_cat;
 243   };
 244
 245   // 19.4.3.6 non-member functions
 246   inline error_condition
 247   make_error_condition(errc __e)
 248   { return error_condition(static_cast<int>(__e), generic_category()); }
 249
 250   inline bool
 251   operator<(const error_condition& __lhs, const error_condition& __rhs)
 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)
 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)
 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)
 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, const error_condition& __rhs)
 280   {
 281     return (__lhs.category() == __rhs.category()
 282             && __lhs.value() == __rhs.value());
 283   }
 284
 285   inline bool
 286   operator!=(const error_code& __lhs, const error_code& __rhs)
 287   { return !(__lhs == __rhs); }
 288
 289   inline bool
 290   operator!=(const error_code& __lhs, const error_condition& __rhs)
 291   { return !(__lhs == __rhs); }
 292
 293   inline bool
 294   operator!=(const error_condition& __lhs, const error_code& __rhs)
 295   { return !(__lhs == __rhs); }
 296
 297   inline bool
 298   operator!=(const error_condition& __lhs, const error_condition& __rhs)
 299   { return !(__lhs == __rhs); }
 300
 301
 302   /**
 303    *  @brief Thrown to indicate error code of underlying system.
 304    *
 305    *  @ingroup exceptions
 306    */
 307   class system_error : public std::runtime_error
 308   {
 309   private:
 310     error_code  _M_code;
 311
 312   public:
 313     system_error(error_code __ec = error_code())
 314     : runtime_error(""), _M_code(__ec) { }
 315
 316     system_error(error_code __ec, const string& __what)
 317     : runtime_error(__what), _M_code(__ec) { }
 318
 319     /*
 320      * TODO: Add const char* ctors to all exceptions.
 321      *
 322      * system_error(error_code __ec, const char* __what)
 323      * : runtime_error(__what), _M_code(__ec) { }
 324      *
 325      * system_error(int __v, const error_category& __ecat, const char* __what)
 326      * : runtime_error(__what), _M_code(error_code(__v, __ecat)) { }
 327      */
 328
 329     system_error(int __v, const error_category& __ecat)
 330     : runtime_error(""), _M_code(error_code(__v, __ecat)) { }
 331
 332     system_error(int __v, const error_category& __ecat, const string& __what)
 333     : runtime_error(__what), _M_code(error_code(__v, __ecat)) { }
 334
 335     virtual ~system_error() throw();
 336
 337     const error_code&
 338     code() const throw() { return _M_code; }
 339   };
 340
 341 _GLIBCXX_END_NAMESPACE
 342
 343 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
 344
 345 #include <bits/functional_hash.h>
 346
 347 _GLIBCXX_BEGIN_NAMESPACE(std)
 348
 349   // DR 1182.
 350   /// std::hash specialization for error_code.
 351   template<>
 352     struct hash<error_code>
 353     : public std::unary_function<error_code, size_t>
 354     {
 355       size_t
 356       operator()(const error_code& __e) const
 357       {
 358         const size_t __tmp = std::_Fnv_hash::hash(__e._M_value);
 359         return std::_Fnv_hash::__hash_combine(__e._M_cat, __tmp);
 360       }
 361     };
 362
 363 _GLIBCXX_END_NAMESPACE
 364
 365 #endif // _GLIBCXX_COMPATIBILITY_CXX0X
 366
 367 #endif // __GXX_EXPERIMENTAL_CXX0X__
 368
 369 #endif // _GLIBCXX_SYSTEM_ERROR
 370