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

   1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
   2
   3 // Copyright (C) 2008 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 2, 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 // You should have received a copy of the GNU General Public License
  18 // along with GCC; see the file COPYING.  If not, write to
  19 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  20 // Boston, MA 02110-1301, USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file exception_ptr.h
  32  *  This is an internal header file, included by other headers and the
  33  *  implementation. You should not attempt to use it directly.
  34  */
  35
  36 #ifndef _EXCEPTION_PTR_H
  37 #define _EXCEPTION_PTR_H
  38
  39 #pragma GCC visibility push(default)
  40
  41 #include <bits/c++config.h>
  42
  43 #if !defined(_GLIBCXX_ATOMIC_BUILTINS_4)
  44 #  error This platform does not support exception propagation.
  45 #endif
  46
  47 extern "C++" {
  48
  49 namespace std
  50 {
  51   // Hide the free operators from other types
  52   namespace __exception_ptr
  53   {
  54     /**
  55      * @brief An opaque pointer to an arbitrary exception.
  56      */
  57     class exception_ptr;
  58   }
  59
  60   using __exception_ptr::exception_ptr;
  61
  62   /** Obtain an %exception_ptr to the currently handled exception. If there
  63    *  is none, or the currently handled exception is foreign, return the null
  64    *  value.
  65    */
  66   exception_ptr current_exception() throw();
  67
  68   /// Throw the object pointed to by the %exception_ptr.
  69   void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
  70
  71   /// Obtain an %exception_ptr pointing to a copy of the supplied object.
  72   template <class _Ex>
  73   exception_ptr copy_exception(_Ex __ex) throw();
  74
  75
  76   namespace __exception_ptr
  77   {
  78     bool operator==(const exception_ptr&,
  79                     const exception_ptr&) throw();
  80     bool operator!=(const exception_ptr&,
  81                     const exception_ptr&) throw();
  82
  83     class exception_ptr
  84     {
  85       void* _M_exception_object;
  86
  87       explicit exception_ptr(void* __e) throw();
  88
  89       void _M_addref() throw();
  90       void _M_release() throw();
  91
  92       void *_M_get() const throw();
  93
  94       void _M_safe_bool_dummy();
  95
  96       friend exception_ptr std::current_exception() throw();
  97       friend void std::rethrow_exception(exception_ptr);
  98
  99     public:
 100       exception_ptr() throw();
 101
 102       typedef void (exception_ptr::*__safe_bool)();
 103
 104       // For construction from nullptr or 0.
 105       exception_ptr(__safe_bool) throw();
 106
 107       exception_ptr(const exception_ptr&) throw();
 108
 109 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 110       exception_ptr(exception_ptr&& __o) throw()
 111         : _M_exception_object(__o._M_exception_object)
 112       {
 113         __o._M_exception_object = 0;
 114       }
 115 #endif
 116
 117       exception_ptr& operator=(const exception_ptr&) throw();
 118
 119 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 120       exception_ptr& operator=(exception_ptr&& __o) throw()
 121       {
 122         exception_ptr(__o).swap(*this);
 123         return *this;
 124       }
 125 #endif
 126
 127       ~exception_ptr() throw();
 128
 129       void swap(exception_ptr&) throw();
 130
 131 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 132       void swap(exception_ptr &&__o) throw()
 133       {
 134         void *__tmp = _M_exception_object;
 135         _M_exception_object = __o._M_exception_object;
 136         __o._M_exception_object = __tmp;
 137       }
 138 #endif
 139
 140       bool operator!() const throw();
 141       operator __safe_bool() const throw();
 142
 143       friend bool operator==(const exception_ptr&,
 144                              const exception_ptr&) throw();
 145
 146       const type_info *__cxa_exception_type() const throw();
 147     };
 148
 149   } // namespace __exception_ptr
 150
 151
 152   template <class _Ex>
 153   exception_ptr copy_exception(_Ex __ex) throw()
 154   {
 155     try
 156       {
 157         throw __ex;
 158       }
 159     catch(...)
 160       {
 161         return current_exception ();
 162       }
 163   }
 164
 165 } // namespace std
 166
 167 } // extern "C++"
 168
 169 #pragma GCC visibility pop
 170
 171 #endif