libstdc++-v3/libsupc++/exception_ptr.h

   1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
   2
   3 // Copyright (C) 2008, 2009 Free Software Foundation
   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 exception_ptr.h
  27  *  This is an internal header file, included by other headers and the
  28  *  implementation. You should not attempt to use it directly.
  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 <exception_defines.h>
  38
  39 #if !defined(_GLIBCXX_ATOMIC_BUILTINS_4)
  40 #  error This platform does not support exception propagation.
  41 #endif
  42
  43 extern "C++" {
  44
  45 namespace std
  46 {
  47   /**
  48    * @addtogroup exceptions
  49    * @{
  50    */
  51
  52   // Hide the free operators from other types
  53   namespace __exception_ptr
  54   {
  55     /**
  56      * @brief An opaque pointer to an arbitrary exception.
  57      */
  58     class exception_ptr;
  59   }
  60
  61   using __exception_ptr::exception_ptr;
  62
  63   /** Obtain an %exception_ptr to the currently handled exception. If there
  64    *  is none, or the currently handled exception is foreign, return the null
  65    *  value.
  66    */
  67   exception_ptr current_exception() throw();
  68
  69   /// Throw the object pointed to by the %exception_ptr.
  70   void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
  71
  72   /// Obtain an %exception_ptr pointing to a copy of the supplied object.
  73   template<typename _Ex>
  74     exception_ptr
  75     copy_exception(_Ex __ex) throw();
  76
  77   namespace __exception_ptr
  78   {
  79     bool
  80     operator==(const exception_ptr&, const exception_ptr&)
  81       throw() __attribute__ ((__pure__));
  82
  83     bool
  84     operator!=(const exception_ptr&, const exception_ptr&)
  85       throw() __attribute__ ((__pure__));
  86
  87     class exception_ptr
  88     {
  89       void* _M_exception_object;
  90
  91       explicit exception_ptr(void* __e) throw();
  92
  93       void _M_addref() throw();
  94       void _M_release() throw();
  95
  96       void *_M_get() const throw() __attribute__ ((__pure__));
  97
  98       void _M_safe_bool_dummy() throw() __attribute__ ((__const__));
  99
 100       friend exception_ptr std::current_exception() throw();
 101       friend void std::rethrow_exception(exception_ptr);
 102
 103     public:
 104       exception_ptr() throw();
 105
 106       typedef void (exception_ptr::*__safe_bool)();
 107
 108       // For construction from nullptr or 0.
 109       exception_ptr(__safe_bool) throw();
 110
 111       exception_ptr(const exception_ptr&) throw();
 112
 113 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 114       exception_ptr(exception_ptr&& __o) throw()
 115       : _M_exception_object(__o._M_exception_object)
 116       { __o._M_exception_object = 0; }
 117 #endif
 118
 119       exception_ptr&
 120       operator=(const exception_ptr&) throw();
 121
 122 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 123       exception_ptr&
 124       operator=(exception_ptr&& __o) throw()
 125       {
 126         exception_ptr(__o).swap(*this);
 127         return *this;
 128       }
 129 #endif
 130
 131       ~exception_ptr() throw();
 132
 133       void
 134       swap(exception_ptr&) throw();
 135
 136 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 137       void
 138       swap(exception_ptr &&__o) throw()
 139       {
 140         void *__tmp = _M_exception_object;
 141         _M_exception_object = __o._M_exception_object;
 142         __o._M_exception_object = __tmp;
 143       }
 144 #endif
 145
 146 #ifdef _GLIBCXX_EH_PTR_COMPAT
 147       // Retained for compatibility with CXXABI_1.3.
 148       bool operator!() const throw() __attribute__ ((__pure__));
 149       operator __safe_bool() const throw();
 150 #endif
 151
 152       friend bool
 153       operator==(const exception_ptr&, const exception_ptr&)
 154         throw() __attribute__ ((__pure__));
 155
 156       const type_info*
 157       __cxa_exception_type() const throw() __attribute__ ((__pure__));
 158     };
 159
 160   } // namespace __exception_ptr
 161
 162
 163   template<typename _Ex>
 164     exception_ptr
 165     copy_exception(_Ex __ex) throw()
 166     {
 167       __try
 168         {
 169           throw __ex;
 170         }
 171       __catch(...)
 172         {
 173           return current_exception ();
 174         }
 175     }
 176
 177   // @} group exceptions
 178 } // namespace std
 179
 180 } // extern "C++"
 181
 182 #pragma GCC visibility pop
 183
 184 #endif