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      1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
      2 
      3 // Copyright (C) 2008-2013 Free Software Foundation, Inc.
      4 //
      5 // This file is part of GCC.
      6 //
      7 // GCC is free software; you can redistribute it and/or modify
      8 // it under the terms of the GNU General Public License as published by
      9 // the Free Software Foundation; either version 3, or (at your option)
     10 // any later version.
     11 //
     12 // GCC is distributed in the hope that it will be useful,
     13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     15 // GNU General Public License for more details.
     16 //
     17 // Under Section 7 of GPL version 3, you are granted additional
     18 // permissions described in the GCC Runtime Library Exception, version
     19 // 3.1, as published by the Free Software Foundation.
     20 
     21 // You should have received a copy of the GNU General Public License and
     22 // a copy of the GCC Runtime Library Exception along with this program;
     23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     24 // <http://www.gnu.org/licenses/>.
     25 
     26 /** @file bits/exception_ptr.h
     27  *  This is an internal header file, included by other library headers.
     28  *  Do not attempt to use it directly. @headername{exception}
     29  */
     30 
     31 #ifndef _EXCEPTION_PTR_H
     32 #define _EXCEPTION_PTR_H
     33 
     34 #pragma GCC visibility push(default)
     35 
     36 #include <bits/c++config.h>
     37 #include <bits/exception_defines.h>
     38 
     39 #if ATOMIC_INT_LOCK_FREE < 2
     40 #  error This platform does not support exception propagation.
     41 #endif
     42 
     43 extern "C++" {
     44 
     45 namespace std
     46 {
     47   class type_info;
     48 
     49   /**
     50    * @addtogroup exceptions
     51    * @{
     52    */
     53   namespace __exception_ptr
     54   {
     55     class exception_ptr;
     56   }
     57 
     58   using __exception_ptr::exception_ptr;
     59 
     60   /** Obtain an exception_ptr to the currently handled exception. If there
     61    *  is none, or the currently handled exception is foreign, return the null
     62    *  value.
     63    */
     64   exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT;
     65 
     66   /// Throw the object pointed to by the exception_ptr.
     67   void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
     68 
     69   namespace __exception_ptr
     70   {
     71     /**
     72      *  @brief An opaque pointer to an arbitrary exception.
     73      *  @ingroup exceptions
     74      */
     75     class exception_ptr
     76     {
     77       void* _M_exception_object;
     78 
     79       explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
     80 
     81       void _M_addref() _GLIBCXX_USE_NOEXCEPT;
     82       void _M_release() _GLIBCXX_USE_NOEXCEPT;
     83 
     84       void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
     85 
     86       friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
     87       friend void std::rethrow_exception(exception_ptr);
     88 
     89     public:
     90       exception_ptr() _GLIBCXX_USE_NOEXCEPT;
     91 
     92       exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
     93 
     94 #if __cplusplus >= 201103L
     95       exception_ptr(nullptr_t) noexcept
     96       : _M_exception_object(0)
     97       { }
     98 
     99       exception_ptr(exception_ptr&& __o) noexcept
    100       : _M_exception_object(__o._M_exception_object)
    101       { __o._M_exception_object = 0; }
    102 #endif
    103 
    104 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
    105       typedef void (exception_ptr::*__safe_bool)();
    106 
    107       // For construction from nullptr or 0.
    108       exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
    109 #endif
    110 
    111       exception_ptr&
    112       operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
    113 
    114 #if __cplusplus >= 201103L
    115       exception_ptr&
    116       operator=(exception_ptr&& __o) noexcept
    117       {
    118         exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
    119         return *this;
    120       }
    121 #endif
    122 
    123       ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
    124 
    125       void
    126       swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
    127 
    128 #ifdef _GLIBCXX_EH_PTR_COMPAT
    129       // Retained for compatibility with CXXABI_1.3.
    130       void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
    131 	__attribute__ ((__const__));
    132       bool operator!() const _GLIBCXX_USE_NOEXCEPT
    133 	__attribute__ ((__pure__));
    134       operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
    135 #endif
    136 
    137 #if __cplusplus >= 201103L
    138       explicit operator bool() const
    139       { return _M_exception_object; }
    140 #endif
    141 
    142       friend bool
    143       operator==(const exception_ptr&, const exception_ptr&)
    144 	_GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
    145 
    146       const class std::type_info*
    147       __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
    148 	__attribute__ ((__pure__));
    149     };
    150 
    151     bool
    152     operator==(const exception_ptr&, const exception_ptr&)
    153       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
    154 
    155     bool
    156     operator!=(const exception_ptr&, const exception_ptr&)
    157       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
    158 
    159     inline void
    160     swap(exception_ptr& __lhs, exception_ptr& __rhs)
    161     { __lhs.swap(__rhs); }
    162 
    163   } // namespace __exception_ptr
    164 
    165 
    166   /// Obtain an exception_ptr pointing to a copy of the supplied object.
    167   template<typename _Ex>
    168     exception_ptr
    169     copy_exception(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
    170     {
    171       __try
    172 	{
    173 #ifdef __EXCEPTIONS
    174 	  throw __ex;
    175 #endif
    176 	}
    177       __catch(...)
    178 	{
    179 	  return current_exception();
    180 	}
    181     }
    182 
    183   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    184   // 1130. copy_exception name misleading
    185   /// Obtain an exception_ptr pointing to a copy of the supplied object.
    186   template<typename _Ex>
    187     exception_ptr
    188     make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
    189     { return std::copy_exception<_Ex>(__ex); }
    190 
    191   // @} group exceptions
    192 } // namespace std
    193 
    194 } // extern "C++"
    195 
    196 #pragma GCC visibility pop
    197 
    198 #endif
    199