Home | History | Annotate | Download | only in include
      1 // -*- C++ -*-
      2 //===---------------------------- system_error ----------------------------===//
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is dual licensed under the MIT and the University of Illinois Open
      7 // Source Licenses. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #ifndef _LIBCPP_SYSTEM_ERROR
     12 #define _LIBCPP_SYSTEM_ERROR
     13 
     14 /*
     15     system_error synopsis
     16 
     17 namespace std
     18 {
     19 
     20 class error_category
     21 {
     22 public:
     23     virtual ~error_category() noexcept;
     24 
     25     constexpr error_category();
     26     error_category(const error_category&) = delete;
     27     error_category& operator=(const error_category&) = delete;
     28 
     29     virtual const char* name() const noexcept = 0;
     30     virtual error_condition default_error_condition(int ev) const noexcept;
     31     virtual bool equivalent(int code, const error_condition& condition) const noexcept;
     32     virtual bool equivalent(const error_code& code, int condition) const noexcept;
     33     virtual string message(int ev) const = 0;
     34 
     35     bool operator==(const error_category& rhs) const noexcept;
     36     bool operator!=(const error_category& rhs) const noexcept;
     37     bool operator<(const error_category& rhs) const noexcept;
     38 };
     39 
     40 const error_category& generic_category() noexcept;
     41 const error_category& system_category() noexcept;
     42 
     43 template <class T> struct is_error_code_enum
     44     : public false_type {};
     45 
     46 template <class T> struct is_error_condition_enum
     47     : public false_type {};
     48 
     49 class error_code
     50 {
     51 public:
     52     // constructors:
     53     error_code() noexcept;
     54     error_code(int val, const error_category& cat) noexcept;
     55     template <class ErrorCodeEnum>
     56         error_code(ErrorCodeEnum e) noexcept;
     57 
     58     // modifiers:
     59     void assign(int val, const error_category& cat) noexcept;
     60     template <class ErrorCodeEnum>
     61         error_code& operator=(ErrorCodeEnum e) noexcept;
     62     void clear() noexcept;
     63 
     64     // observers:
     65     int value() const noexcept;
     66     const error_category& category() const noexcept;
     67     error_condition default_error_condition() const noexcept;
     68     string message() const;
     69     explicit operator bool() const noexcept;
     70 };
     71 
     72 // non-member functions:
     73 bool operator<(const error_code& lhs, const error_code& rhs) noexcept;
     74 template <class charT, class traits>
     75     basic_ostream<charT,traits>&
     76     operator<<(basic_ostream<charT,traits>& os, const error_code& ec);
     77 
     78 class error_condition
     79 {
     80 public:
     81     // constructors:
     82     error_condition() noexcept;
     83     error_condition(int val, const error_category& cat) noexcept;
     84     template <class ErrorConditionEnum>
     85         error_condition(ErrorConditionEnum e) noexcept;
     86 
     87     // modifiers:
     88     void assign(int val, const error_category& cat) noexcept;
     89     template <class ErrorConditionEnum>
     90         error_condition& operator=(ErrorConditionEnum e) noexcept;
     91     void clear() noexcept;
     92 
     93     // observers:
     94     int value() const noexcept;
     95     const error_category& category() const noexcept;
     96     string message() const noexcept;
     97     explicit operator bool() const noexcept;
     98 };
     99 
    100 bool operator<(const error_condition& lhs, const error_condition& rhs) noexcept;
    101 
    102 class system_error
    103     : public runtime_error
    104 {
    105 public:
    106     system_error(error_code ec, const string& what_arg);
    107     system_error(error_code ec, const char* what_arg);
    108     system_error(error_code ec);
    109     system_error(int ev, const error_category& ecat, const string& what_arg);
    110     system_error(int ev, const error_category& ecat, const char* what_arg);
    111     system_error(int ev, const error_category& ecat);
    112 
    113     const error_code& code() const noexcept;
    114     const char* what() const noexcept;
    115 };
    116 
    117 enum class errc
    118 {
    119     address_family_not_supported,       // EAFNOSUPPORT
    120     address_in_use,                     // EADDRINUSE
    121     address_not_available,              // EADDRNOTAVAIL
    122     already_connected,                  // EISCONN
    123     argument_list_too_long,             // E2BIG
    124     argument_out_of_domain,             // EDOM
    125     bad_address,                        // EFAULT
    126     bad_file_descriptor,                // EBADF
    127     bad_message,                        // EBADMSG
    128     broken_pipe,                        // EPIPE
    129     connection_aborted,                 // ECONNABORTED
    130     connection_already_in_progress,     // EALREADY
    131     connection_refused,                 // ECONNREFUSED
    132     connection_reset,                   // ECONNRESET
    133     cross_device_link,                  // EXDEV
    134     destination_address_required,       // EDESTADDRREQ
    135     device_or_resource_busy,            // EBUSY
    136     directory_not_empty,                // ENOTEMPTY
    137     executable_format_error,            // ENOEXEC
    138     file_exists,                        // EEXIST
    139     file_too_large,                     // EFBIG
    140     filename_too_long,                  // ENAMETOOLONG
    141     function_not_supported,             // ENOSYS
    142     host_unreachable,                   // EHOSTUNREACH
    143     identifier_removed,                 // EIDRM
    144     illegal_byte_sequence,              // EILSEQ
    145     inappropriate_io_control_operation, // ENOTTY
    146     interrupted,                        // EINTR
    147     invalid_argument,                   // EINVAL
    148     invalid_seek,                       // ESPIPE
    149     io_error,                           // EIO
    150     is_a_directory,                     // EISDIR
    151     message_size,                       // EMSGSIZE
    152     network_down,                       // ENETDOWN
    153     network_reset,                      // ENETRESET
    154     network_unreachable,                // ENETUNREACH
    155     no_buffer_space,                    // ENOBUFS
    156     no_child_process,                   // ECHILD
    157     no_link,                            // ENOLINK
    158     no_lock_available,                  // ENOLCK
    159     no_message_available,               // ENODATA
    160     no_message,                         // ENOMSG
    161     no_protocol_option,                 // ENOPROTOOPT
    162     no_space_on_device,                 // ENOSPC
    163     no_stream_resources,                // ENOSR
    164     no_such_device_or_address,          // ENXIO
    165     no_such_device,                     // ENODEV
    166     no_such_file_or_directory,          // ENOENT
    167     no_such_process,                    // ESRCH
    168     not_a_directory,                    // ENOTDIR
    169     not_a_socket,                       // ENOTSOCK
    170     not_a_stream,                       // ENOSTR
    171     not_connected,                      // ENOTCONN
    172     not_enough_memory,                  // ENOMEM
    173     not_supported,                      // ENOTSUP
    174     operation_canceled,                 // ECANCELED
    175     operation_in_progress,              // EINPROGRESS
    176     operation_not_permitted,            // EPERM
    177     operation_not_supported,            // EOPNOTSUPP
    178     operation_would_block,              // EWOULDBLOCK
    179     owner_dead,                         // EOWNERDEAD
    180     permission_denied,                  // EACCES
    181     protocol_error,                     // EPROTO
    182     protocol_not_supported,             // EPROTONOSUPPORT
    183     read_only_file_system,              // EROFS
    184     resource_deadlock_would_occur,      // EDEADLK
    185     resource_unavailable_try_again,     // EAGAIN
    186     result_out_of_range,                // ERANGE
    187     state_not_recoverable,              // ENOTRECOVERABLE
    188     stream_timeout,                     // ETIME
    189     text_file_busy,                     // ETXTBSY
    190     timed_out,                          // ETIMEDOUT
    191     too_many_files_open_in_system,      // ENFILE
    192     too_many_files_open,                // EMFILE
    193     too_many_links,                     // EMLINK
    194     too_many_symbolic_link_levels,      // ELOOP
    195     value_too_large,                    // EOVERFLOW
    196     wrong_protocol_type                 // EPROTOTYPE
    197 };
    198 
    199 template <> struct is_error_condition_enum<errc>
    200     : true_type { }
    201 
    202 error_code make_error_code(errc e) noexcept;
    203 error_condition make_error_condition(errc e) noexcept;
    204 
    205 // Comparison operators:
    206 bool operator==(const error_code& lhs, const error_code& rhs) noexcept;
    207 bool operator==(const error_code& lhs, const error_condition& rhs) noexcept;
    208 bool operator==(const error_condition& lhs, const error_code& rhs) noexcept;
    209 bool operator==(const error_condition& lhs, const error_condition& rhs) noexcept;
    210 bool operator!=(const error_code& lhs, const error_code& rhs) noexcept;
    211 bool operator!=(const error_code& lhs, const error_condition& rhs) noexcept;
    212 bool operator!=(const error_condition& lhs, const error_code& rhs) noexcept;
    213 bool operator!=(const error_condition& lhs, const error_condition& rhs) noexcept;
    214 
    215 template <> struct hash<std::error_code>;
    216 
    217 }  // std
    218 
    219 */
    220 
    221 #include <__config>
    222 #include <cerrno>
    223 #include <type_traits>
    224 #include <stdexcept>
    225 #include <__functional_base>
    226 
    227 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
    228 #pragma GCC system_header
    229 #endif
    230 
    231 _LIBCPP_BEGIN_NAMESPACE_STD
    232 
    233 // is_error_code_enum
    234 
    235 template <class _Tp>
    236 struct _LIBCPP_TYPE_VIS_ONLY is_error_code_enum
    237     : public false_type {};
    238 
    239 // is_error_condition_enum
    240 
    241 template <class _Tp>
    242 struct _LIBCPP_TYPE_VIS_ONLY is_error_condition_enum
    243     : public false_type {};
    244 
    245 // Some error codes are not present on all platforms, so we provide equivalents
    246 // for them:
    247 
    248 //enum class errc
    249 _LIBCPP_DECLARE_STRONG_ENUM(errc)
    250 {
    251     address_family_not_supported        = EAFNOSUPPORT,
    252     address_in_use                      = EADDRINUSE,
    253     address_not_available               = EADDRNOTAVAIL,
    254     already_connected                   = EISCONN,
    255     argument_list_too_long              = E2BIG,
    256     argument_out_of_domain              = EDOM,
    257     bad_address                         = EFAULT,
    258     bad_file_descriptor                 = EBADF,
    259     bad_message                         = EBADMSG,
    260     broken_pipe                         = EPIPE,
    261     connection_aborted                  = ECONNABORTED,
    262     connection_already_in_progress      = EALREADY,
    263     connection_refused                  = ECONNREFUSED,
    264     connection_reset                    = ECONNRESET,
    265     cross_device_link                   = EXDEV,
    266     destination_address_required        = EDESTADDRREQ,
    267     device_or_resource_busy             = EBUSY,
    268     directory_not_empty                 = ENOTEMPTY,
    269     executable_format_error             = ENOEXEC,
    270     file_exists                         = EEXIST,
    271     file_too_large                      = EFBIG,
    272     filename_too_long                   = ENAMETOOLONG,
    273     function_not_supported              = ENOSYS,
    274     host_unreachable                    = EHOSTUNREACH,
    275     identifier_removed                  = EIDRM,
    276     illegal_byte_sequence               = EILSEQ,
    277     inappropriate_io_control_operation  = ENOTTY,
    278     interrupted                         = EINTR,
    279     invalid_argument                    = EINVAL,
    280     invalid_seek                        = ESPIPE,
    281     io_error                            = EIO,
    282     is_a_directory                      = EISDIR,
    283     message_size                        = EMSGSIZE,
    284     network_down                        = ENETDOWN,
    285     network_reset                       = ENETRESET,
    286     network_unreachable                 = ENETUNREACH,
    287     no_buffer_space                     = ENOBUFS,
    288     no_child_process                    = ECHILD,
    289     no_link                             = ENOLINK,
    290     no_lock_available                   = ENOLCK,
    291 #ifdef ENODATA
    292     no_message_available                = ENODATA,
    293 #else
    294     no_message_available                = ENOMSG,
    295 #endif
    296     no_message                          = ENOMSG,
    297     no_protocol_option                  = ENOPROTOOPT,
    298     no_space_on_device                  = ENOSPC,
    299 #ifdef ENOSR
    300     no_stream_resources                 = ENOSR,
    301 #else
    302     no_stream_resources                 = ENOMEM,
    303 #endif
    304     no_such_device_or_address           = ENXIO,
    305     no_such_device                      = ENODEV,
    306     no_such_file_or_directory           = ENOENT,
    307     no_such_process                     = ESRCH,
    308     not_a_directory                     = ENOTDIR,
    309     not_a_socket                        = ENOTSOCK,
    310 #ifdef ENOSTR
    311     not_a_stream                        = ENOSTR,
    312 #else
    313     not_a_stream                        = EINVAL,
    314 #endif
    315     not_connected                       = ENOTCONN,
    316     not_enough_memory                   = ENOMEM,
    317     not_supported                       = ENOTSUP,
    318     operation_canceled                  = ECANCELED,
    319     operation_in_progress               = EINPROGRESS,
    320     operation_not_permitted             = EPERM,
    321     operation_not_supported             = EOPNOTSUPP,
    322     operation_would_block               = EWOULDBLOCK,
    323     owner_dead                          = EOWNERDEAD,
    324     permission_denied                   = EACCES,
    325     protocol_error                      = EPROTO,
    326     protocol_not_supported              = EPROTONOSUPPORT,
    327     read_only_file_system               = EROFS,
    328     resource_deadlock_would_occur       = EDEADLK,
    329     resource_unavailable_try_again      = EAGAIN,
    330     result_out_of_range                 = ERANGE,
    331     state_not_recoverable               = ENOTRECOVERABLE,
    332 #ifdef ETIME
    333     stream_timeout                      = ETIME,
    334 #else
    335     stream_timeout                      = ETIMEDOUT,
    336 #endif
    337     text_file_busy                      = ETXTBSY,
    338     timed_out                           = ETIMEDOUT,
    339     too_many_files_open_in_system       = ENFILE,
    340     too_many_files_open                 = EMFILE,
    341     too_many_links                      = EMLINK,
    342     too_many_symbolic_link_levels       = ELOOP,
    343     value_too_large                     = EOVERFLOW,
    344     wrong_protocol_type                 = EPROTOTYPE
    345 };
    346 _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(errc)
    347 
    348 template <>
    349 struct _LIBCPP_TYPE_VIS_ONLY is_error_condition_enum<errc>
    350     : true_type { };
    351 
    352 #ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
    353 template <>
    354 struct _LIBCPP_TYPE_VIS_ONLY is_error_condition_enum<errc::__lx>
    355     : true_type { };
    356 #endif
    357 
    358 class _LIBCPP_TYPE_VIS error_condition;
    359 class _LIBCPP_TYPE_VIS error_code;
    360 
    361 // class error_category
    362 
    363 class _LIBCPP_HIDDEN __do_message;
    364 
    365 class _LIBCPP_TYPE_VIS error_category
    366 {
    367 public:
    368     virtual ~error_category() _NOEXCEPT;
    369 
    370 #ifdef _LIBCPP_BUILDING_SYSTEM_ERROR
    371     error_category() _NOEXCEPT;
    372 #else
    373     _LIBCPP_ALWAYS_INLINE
    374     _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT _LIBCPP_DEFAULT;
    375 #endif
    376 private:
    377     error_category(const error_category&);// = delete;
    378     error_category& operator=(const error_category&);// = delete;
    379 
    380 public:
    381     virtual const char* name() const _NOEXCEPT = 0;
    382     virtual error_condition default_error_condition(int __ev) const _NOEXCEPT;
    383     virtual bool equivalent(int __code, const error_condition& __condition) const _NOEXCEPT;
    384     virtual bool equivalent(const error_code& __code, int __condition) const _NOEXCEPT;
    385     virtual string message(int __ev) const = 0;
    386 
    387     _LIBCPP_ALWAYS_INLINE
    388     bool operator==(const error_category& __rhs) const _NOEXCEPT {return this == &__rhs;}
    389 
    390     _LIBCPP_ALWAYS_INLINE
    391     bool operator!=(const error_category& __rhs) const _NOEXCEPT {return !(*this == __rhs);}
    392 
    393     _LIBCPP_ALWAYS_INLINE
    394     bool operator< (const error_category& __rhs) const _NOEXCEPT {return this < &__rhs;}
    395 
    396     friend class _LIBCPP_HIDDEN __do_message;
    397 };
    398 
    399 class _LIBCPP_HIDDEN __do_message
    400     : public error_category
    401 {
    402 public:
    403     virtual string message(int ev) const;
    404 };
    405 
    406 _LIBCPP_FUNC_VIS const error_category& generic_category() _NOEXCEPT;
    407 _LIBCPP_FUNC_VIS const error_category& system_category() _NOEXCEPT;
    408 
    409 class _LIBCPP_TYPE_VIS error_condition
    410 {
    411     int __val_;
    412     const error_category* __cat_;
    413 public:
    414     _LIBCPP_ALWAYS_INLINE
    415     error_condition() _NOEXCEPT : __val_(0), __cat_(&generic_category()) {}
    416 
    417     _LIBCPP_ALWAYS_INLINE
    418     error_condition(int __val, const error_category& __cat) _NOEXCEPT
    419         : __val_(__val), __cat_(&__cat) {}
    420 
    421     template <class _Ep>
    422         _LIBCPP_ALWAYS_INLINE
    423         error_condition(_Ep __e,
    424               typename enable_if<is_error_condition_enum<_Ep>::value>::type* = 0
    425                                                                      ) _NOEXCEPT
    426             {*this = make_error_condition(__e);}
    427 
    428     _LIBCPP_ALWAYS_INLINE
    429     void assign(int __val, const error_category& __cat) _NOEXCEPT
    430     {
    431         __val_ = __val;
    432         __cat_ = &__cat;
    433     }
    434 
    435     template <class _Ep>
    436         _LIBCPP_ALWAYS_INLINE
    437         typename enable_if
    438         <
    439             is_error_condition_enum<_Ep>::value,
    440             error_condition&
    441         >::type
    442         operator=(_Ep __e) _NOEXCEPT
    443             {*this = make_error_condition(__e); return *this;}
    444 
    445     _LIBCPP_ALWAYS_INLINE
    446     void clear() _NOEXCEPT
    447     {
    448         __val_ = 0;
    449         __cat_ = &generic_category();
    450     }
    451 
    452     _LIBCPP_ALWAYS_INLINE
    453     int value() const _NOEXCEPT {return __val_;}
    454 
    455     _LIBCPP_ALWAYS_INLINE
    456     const error_category& category() const _NOEXCEPT {return *__cat_;}
    457     string message() const;
    458 
    459     _LIBCPP_ALWAYS_INLINE
    460         _LIBCPP_EXPLICIT
    461         operator bool() const _NOEXCEPT {return __val_ != 0;}
    462 };
    463 
    464 inline _LIBCPP_INLINE_VISIBILITY
    465 error_condition
    466 make_error_condition(errc __e) _NOEXCEPT
    467 {
    468     return error_condition(static_cast<int>(__e), generic_category());
    469 }
    470 
    471 inline _LIBCPP_INLINE_VISIBILITY
    472 bool
    473 operator<(const error_condition& __x, const error_condition& __y) _NOEXCEPT
    474 {
    475     return __x.category() < __y.category()
    476         || (__x.category() == __y.category() && __x.value() < __y.value());
    477 }
    478 
    479 // error_code
    480 
    481 class _LIBCPP_TYPE_VIS error_code
    482 {
    483     int __val_;
    484     const error_category* __cat_;
    485 public:
    486     _LIBCPP_ALWAYS_INLINE
    487     error_code() _NOEXCEPT : __val_(0), __cat_(&system_category()) {}
    488 
    489     _LIBCPP_ALWAYS_INLINE
    490     error_code(int __val, const error_category& __cat) _NOEXCEPT
    491         : __val_(__val), __cat_(&__cat) {}
    492 
    493     template <class _Ep>
    494         _LIBCPP_ALWAYS_INLINE
    495         error_code(_Ep __e,
    496                    typename enable_if<is_error_code_enum<_Ep>::value>::type* = 0
    497                                                                      ) _NOEXCEPT
    498             {*this = make_error_code(__e);}
    499 
    500     _LIBCPP_ALWAYS_INLINE
    501     void assign(int __val, const error_category& __cat) _NOEXCEPT
    502     {
    503         __val_ = __val;
    504         __cat_ = &__cat;
    505     }
    506 
    507     template <class _Ep>
    508         _LIBCPP_ALWAYS_INLINE
    509         typename enable_if
    510         <
    511             is_error_code_enum<_Ep>::value,
    512             error_code&
    513         >::type
    514         operator=(_Ep __e) _NOEXCEPT
    515             {*this = make_error_code(__e); return *this;}
    516 
    517     _LIBCPP_ALWAYS_INLINE
    518     void clear() _NOEXCEPT
    519     {
    520         __val_ = 0;
    521         __cat_ = &system_category();
    522     }
    523 
    524     _LIBCPP_ALWAYS_INLINE
    525     int value() const _NOEXCEPT {return __val_;}
    526 
    527     _LIBCPP_ALWAYS_INLINE
    528     const error_category& category() const _NOEXCEPT {return *__cat_;}
    529 
    530     _LIBCPP_ALWAYS_INLINE
    531     error_condition default_error_condition() const _NOEXCEPT
    532         {return __cat_->default_error_condition(__val_);}
    533 
    534     string message() const;
    535 
    536     _LIBCPP_ALWAYS_INLINE
    537         _LIBCPP_EXPLICIT
    538         operator bool() const _NOEXCEPT {return __val_ != 0;}
    539 };
    540 
    541 inline _LIBCPP_INLINE_VISIBILITY
    542 error_code
    543 make_error_code(errc __e) _NOEXCEPT
    544 {
    545     return error_code(static_cast<int>(__e), generic_category());
    546 }
    547 
    548 inline _LIBCPP_INLINE_VISIBILITY
    549 bool
    550 operator<(const error_code& __x, const error_code& __y) _NOEXCEPT
    551 {
    552     return __x.category() < __y.category()
    553         || (__x.category() == __y.category() && __x.value() < __y.value());
    554 }
    555 
    556 inline _LIBCPP_INLINE_VISIBILITY
    557 bool
    558 operator==(const error_code& __x, const error_code& __y) _NOEXCEPT
    559 {
    560     return __x.category() == __y.category() && __x.value() == __y.value();
    561 }
    562 
    563 inline _LIBCPP_INLINE_VISIBILITY
    564 bool
    565 operator==(const error_code& __x, const error_condition& __y) _NOEXCEPT
    566 {
    567     return __x.category().equivalent(__x.value(), __y)
    568         || __y.category().equivalent(__x, __y.value());
    569 }
    570 
    571 inline _LIBCPP_INLINE_VISIBILITY
    572 bool
    573 operator==(const error_condition& __x, const error_code& __y) _NOEXCEPT
    574 {
    575     return __y == __x;
    576 }
    577 
    578 inline _LIBCPP_INLINE_VISIBILITY
    579 bool
    580 operator==(const error_condition& __x, const error_condition& __y) _NOEXCEPT
    581 {
    582     return __x.category() == __y.category() && __x.value() == __y.value();
    583 }
    584 
    585 inline _LIBCPP_INLINE_VISIBILITY
    586 bool
    587 operator!=(const error_code& __x, const error_code& __y) _NOEXCEPT
    588 {return !(__x == __y);}
    589 
    590 inline _LIBCPP_INLINE_VISIBILITY
    591 bool
    592 operator!=(const error_code& __x, const error_condition& __y) _NOEXCEPT
    593 {return !(__x == __y);}
    594 
    595 inline _LIBCPP_INLINE_VISIBILITY
    596 bool
    597 operator!=(const error_condition& __x, const error_code& __y) _NOEXCEPT
    598 {return !(__x == __y);}
    599 
    600 inline _LIBCPP_INLINE_VISIBILITY
    601 bool
    602 operator!=(const error_condition& __x, const error_condition& __y) _NOEXCEPT
    603 {return !(__x == __y);}
    604 
    605 template <>
    606 struct _LIBCPP_TYPE_VIS_ONLY hash<error_code>
    607     : public unary_function<error_code, size_t>
    608 {
    609     _LIBCPP_INLINE_VISIBILITY
    610     size_t operator()(const error_code& __ec) const _NOEXCEPT
    611     {
    612         return static_cast<size_t>(__ec.value());
    613     }
    614 };
    615 
    616 // system_error
    617 
    618 class _LIBCPP_TYPE_VIS system_error
    619     : public runtime_error
    620 {
    621     error_code __ec_;
    622 public:
    623     system_error(error_code __ec, const string& __what_arg);
    624     system_error(error_code __ec, const char* __what_arg);
    625     system_error(error_code __ec);
    626     system_error(int __ev, const error_category& __ecat, const string& __what_arg);
    627     system_error(int __ev, const error_category& __ecat, const char* __what_arg);
    628     system_error(int __ev, const error_category& __ecat);
    629     ~system_error() _NOEXCEPT;
    630 
    631     _LIBCPP_ALWAYS_INLINE
    632     const error_code& code() const _NOEXCEPT {return __ec_;}
    633 
    634 private:
    635     static string __init(const error_code&, string);
    636 };
    637 
    638 _LIBCPP_FUNC_VIS void __throw_system_error(int ev, const char* what_arg);
    639 
    640 _LIBCPP_END_NAMESPACE_STD
    641 
    642 #endif  // _LIBCPP_SYSTEM_ERROR
    643