libstdc++-v3/include/std/system_error

   1 // <system_error> -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008 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 2, 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 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  19 // Boston, MA 02110-1301, USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file system_error
  31  *  This is a Standard C++ Library header.
  32  */
  33
  34 #ifndef _GLIBCXX_SYSTEM_ERROR
  35 #define _GLIBCXX_SYSTEM_ERROR 1
  36
  37 #pragma GCC system_header
  38
  39 #ifndef __GXX_EXPERIMENTAL_CXX0X__
  40 # include <c++0x_warning.h>
  41 #else
  42
  43 #include <bits/c++config.h>
  44 #include <bits/error_constants.h>
  45 #include <iosfwd>
  46 #include <stdexcept>
  47
  48 _GLIBCXX_BEGIN_NAMESPACE(std)
  49
  50   class error_code;
  51   class error_condition;
  52   class error_category;
  53   class system_error;
  54
  55   /// is_error_code_enum
  56   template<typename _Tp>
  57     struct is_error_code_enum : public false_type { };
  58
  59   template<>
  60     struct is_error_code_enum<errc>
  61     : public true_type { };
  62
  63   /// is_error_condition_enum
  64   template<typename _Tp>
  65     struct is_error_condition_enum : public false_type { };
  66
  67   template<>
  68     struct is_error_condition_enum<errc>
  69     : public true_type { };
  70
  71
  72   /// error_category
  73   class error_category
  74   {
  75   protected:
  76     error_category() = default;
  77
  78   public:
  79     virtual ~error_category() { }
  80
  81     error_category(const error_category&) = delete;
  82     error_category& operator=(const error_category&) = delete;
  83
  84     virtual const char*
  85     name() const = 0;
  86
  87     virtual string
  88     message(int) const = 0;
  89
  90     virtual error_condition
  91     default_error_condition(int __i) const;
  92
  93     virtual bool
  94     equivalent(int __i, const error_condition& __cond) const;
  95
  96     virtual bool
  97     equivalent(const error_code& __code, int __i) const;
  98
  99     bool
 100     operator<(const error_category& __other) const
 101     { return less<const error_category*>()(this, &__other); }
 102
 103     bool
 104     operator==(const error_category& __other) const
 105     { return this == &__other; }
 106
 107     bool
 108     operator!=(const error_category& __other) const
 109     { return this != &__other; }
 110   };
 111
 112   // DR 890.
 113   extern const error_category& system_category;
 114   extern const error_category& generic_category;
 115
 116   /// error_code
 117   // Implementation-specific error identification
 118   struct error_code
 119   {
 120     error_code()
 121     : _M_value(0), _M_cat(&system_category) { }
 122
 123     error_code(int __v, const error_category& __cat)
 124     : _M_value(__v), _M_cat(&__cat) { }
 125
 126     template<typename _ErrorCodeEnum>
 127       error_code(_ErrorCodeEnum __e,
 128       typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type* = 0)
 129       : _M_value(static_cast<int>(__e)), _M_cat(&generic_category)
 130       { }
 131
 132     void
 133     assign(int __v, const error_category& __cat)
 134     {
 135       _M_value = __v;
 136       _M_cat = &__cat;
 137     }
 138
 139     void
 140     clear()
 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)
 148       {
 149         assign(static_cast<int>(__e), generic_category);
 150         return *this;
 151       }
 152
 153     int
 154     value() const { return _M_value; }
 155
 156     const error_category&
 157     category() const { return *_M_cat; }
 158
 159     error_condition
 160     default_error_condition() const;
 161
 162     string
 163     message() const
 164     { return category().message(value()); }
 165
 166     // Safe bool idiom.
 167     // explicit operator bool() const throw()
 168     // { return _M_value != 0; }
 169     typedef void (*__bool_type)();
 170
 171     static void __not_bool_type() { }
 172
 173     operator __bool_type() const
 174     { return _M_value != 0 ? &__not_bool_type : false; }
 175
 176     // DR 804.
 177   private:
 178     int                         _M_value;
 179     const error_category*       _M_cat;
 180   };
 181
 182   // 19.4.2.6 non-member functions
 183   inline error_code
 184   make_error_code(errc __e)
 185   { return error_code(static_cast<int>(__e), generic_category); }
 186
 187   inline bool
 188   operator<(const error_code& __lhs, const error_code& __rhs)
 189   {
 190     return (__lhs.category() < __rhs.category()
 191             || (__lhs.category() == __rhs.category()
 192                 && __lhs.value() < __rhs.value()));
 193   }
 194
 195   template<typename _CharT, typename _Traits>
 196     basic_ostream<_CharT, _Traits>&
 197     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
 198     { return (__os << __e.category().name() << ':' << __e.value()); }
 199
 200
 201   /// error_condition
 202   // Portable error identification
 203   struct error_condition
 204   {
 205     error_condition() : _M_value(0), _M_cat(&generic_category) { }
 206
 207     error_condition(int __v, const error_category& __cat)
 208     : _M_value(__v), _M_cat(&__cat) { }
 209
 210     template<typename _ErrorConditionEnum>
 211       error_condition(_ErrorConditionEnum __e,
 212                       typename enable_if<is_error_condition_enum
 213                                       <_ErrorConditionEnum>::value>::type* = 0)
 214       : _M_value(static_cast<int>(__e)), _M_cat(&generic_category) { }
 215
 216     void
 217     assign(int __v, const error_category& __cat)
 218     {
 219       _M_value = __v;
 220       _M_cat = &__cat;
 221     }
 222
 223     // DR 804.
 224     template<typename _ErrorConditionEnum>
 225       typename enable_if<is_error_condition_enum
 226                          <_ErrorConditionEnum>::value, error_condition&>::type
 227       operator=(_ErrorConditionEnum __e)
 228       {
 229         assign(static_cast<int>(__e), generic_category);
 230         return *this;
 231       }
 232
 233     void
 234     clear()
 235     { assign(0, generic_category); }
 236
 237     // 19.4.3.4 observers
 238     int
 239     value() const { return _M_value; }
 240
 241     const error_category&
 242     category() const { return *_M_cat; }
 243
 244     string
 245     message() const
 246     { return category().message(value()); }
 247
 248     // Safe bool idiom.
 249     // explicit operator bool() const throw()
 250     // { return _M_value != 0; }
 251     typedef void (*__bool_type)();
 252
 253     static void __not_bool_type() { }
 254
 255     operator __bool_type() const
 256     { return _M_value != 0 ? &__not_bool_type : false; }
 257
 258     // DR 804.
 259   private:
 260     int                         _M_value;
 261     const error_category*       _M_cat;
 262   };
 263
 264   // 19.4.3.6 non-member functions
 265   inline error_condition
 266   make_error_condition(errc __e)
 267   { return error_condition(static_cast<int>(__e), generic_category); }
 268
 269   inline bool
 270   operator<(const error_condition& __lhs, const error_condition& __rhs)
 271   {
 272     return (__lhs.category() < __rhs.category()
 273             || (__lhs.category() == __rhs.category()
 274                 && __lhs.value() < __rhs.value()));
 275   }
 276
 277   // 19.4.4 Comparison operators
 278   inline bool
 279   operator==(const error_code& __lhs, const error_code& __rhs)
 280   { return (__lhs.category() == __rhs.category()
 281             && __lhs.value() == __rhs.value()); }
 282
 283   inline bool
 284   operator==(const error_code& __lhs, const error_condition& __rhs)
 285   {
 286     return (__lhs.category().equivalent(__lhs.value(), __rhs)
 287             || __rhs.category().equivalent(__lhs, __rhs.value()));
 288   }
 289
 290   inline bool
 291   operator==(const error_condition& __lhs, const error_code& __rhs)
 292   {
 293     return (__rhs.category().equivalent(__rhs.value(), __lhs)
 294             || __lhs.category().equivalent(__rhs, __lhs.value()));
 295   }
 296
 297   inline bool
 298   operator==(const error_condition& __lhs, const error_condition& __rhs)
 299   {
 300     return (__lhs.category() == __rhs.category()
 301             && __lhs.value() == __rhs.value());
 302   }
 303
 304   inline bool
 305   operator!=(const error_code& __lhs, const error_code& __rhs)
 306   { return !(__lhs == __rhs); }
 307
 308   inline bool
 309   operator!=(const error_code& __lhs, const error_condition& __rhs)
 310   { return !(__lhs == __rhs); }
 311
 312   inline bool
 313   operator!=(const error_condition& __lhs, const error_code& __rhs)
 314   { return !(__lhs == __rhs); }
 315
 316   inline bool
 317   operator!=(const error_condition& __lhs, const error_condition& __rhs)
 318   { return !(__lhs == __rhs); }
 319
 320
 321   /// Thrown to indicate error code of underlying system.
 322   class system_error : public std::runtime_error
 323   {
 324   private:
 325     error_code  _M_code;
 326
 327   public:
 328     system_error(error_code __ec = error_code())
 329     : runtime_error(""), _M_code(__ec) { }
 330
 331     system_error(error_code __ec, const string& __what)
 332     : runtime_error(__what), _M_code(__ec) { }
 333
 334     /*
 335      * TODO: Add const char* ctors to all exceptions.
 336      *
 337      * system_error(error_code __ec, const char* __what)
 338      * : runtime_error(__what), _M_code(__ec) { }
 339      *
 340      * system_error(int __v, const error_category& __ecat, const char* __what)
 341      * : runtime_error(__what), _M_code(error_code(__v, __ecat)) { }
 342      */
 343
 344     system_error(int __v, const error_category& __ecat)
 345     : runtime_error(""), _M_code(error_code(__v, __ecat)) { }
 346
 347     system_error(int __v, const error_category& __ecat, const string& __what)
 348     : runtime_error(__what), _M_code(error_code(__v, __ecat)) { }
 349
 350     virtual ~system_error() throw();
 351
 352     const error_code&
 353     code() const throw() { return _M_code; }
 354   };
 355
 356 _GLIBCXX_END_NAMESPACE
 357
 358 #endif // __GXX_EXPERIMENTAL_CXX0X__
 359
 360 #endif // _GLIBCXX_SYSTEM_ERROR
 361