libstdc++
exception_ptr.h
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1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
2 
3 // Copyright (C) 2008-2016 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>
39 #include <typeinfo>
40 #include <new>
41 
42 #if ATOMIC_INT_LOCK_FREE < 2
43 # error This platform does not support exception propagation.
44 #endif
45 
46 extern "C++" {
47 
48 namespace std
49 {
50  class type_info;
51 
52  /**
53  * @addtogroup exceptions
54  * @{
55  */
56  namespace __exception_ptr
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() _GLIBCXX_USE_NOEXCEPT;
68 
69  template<typename _Ex>
70  exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
71 
72  /// Throw the object pointed to by the exception_ptr.
73  void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
74 
75  namespace __exception_ptr
76  {
78 
79  /**
80  * @brief An opaque pointer to an arbitrary exception.
81  * @ingroup exceptions
82  */
84  {
85  void* _M_exception_object;
86 
87  explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
88 
89  void _M_addref() _GLIBCXX_USE_NOEXCEPT;
90  void _M_release() _GLIBCXX_USE_NOEXCEPT;
91 
92  void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
93 
94  friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
96  template<typename _Ex>
97  friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
98 
99  public:
100  exception_ptr() _GLIBCXX_USE_NOEXCEPT;
101 
102  exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
103 
104 #if __cplusplus >= 201103L
105  exception_ptr(nullptr_t) noexcept
106  : _M_exception_object(0)
107  { }
108 
109  exception_ptr(exception_ptr&& __o) noexcept
110  : _M_exception_object(__o._M_exception_object)
111  { __o._M_exception_object = 0; }
112 #endif
113 
114 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
115  typedef void (exception_ptr::*__safe_bool)();
116 
117  // For construction from nullptr or 0.
118  exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
119 #endif
120 
121  exception_ptr&
122  operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
123 
124 #if __cplusplus >= 201103L
125  exception_ptr&
126  operator=(exception_ptr&& __o) noexcept
127  {
128  exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
129  return *this;
130  }
131 #endif
132 
133  ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
134 
135  void
136  swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
137 
138 #ifdef _GLIBCXX_EH_PTR_COMPAT
139  // Retained for compatibility with CXXABI_1.3.
140  void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
141  __attribute__ ((__const__));
142  bool operator!() const _GLIBCXX_USE_NOEXCEPT
143  __attribute__ ((__pure__));
144  operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
145 #endif
146 
147 #if __cplusplus >= 201103L
148  explicit operator bool() const
149  { return _M_exception_object; }
150 #endif
151 
152  friend bool
153  operator==(const exception_ptr&, const exception_ptr&)
154  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
155 
156  const class std::type_info*
157  __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
158  __attribute__ ((__pure__));
159  };
160 
161  bool
162  operator==(const exception_ptr&, const exception_ptr&)
163  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
164 
165  bool
166  operator!=(const exception_ptr&, const exception_ptr&)
167  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
168 
169  inline void
170  swap(exception_ptr& __lhs, exception_ptr& __rhs)
171  { __lhs.swap(__rhs); }
172 
173  template<typename _Ex>
174  inline void
175  __dest_thunk(void* x)
176  { static_cast<_Ex*>(x)->~_Ex(); }
177 
178  } // namespace __exception_ptr
179 
180  /// Obtain an exception_ptr pointing to a copy of the supplied object.
181  template<typename _Ex>
183  make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
184  {
185 #if __cpp_exceptions
186  try
187  {
188 #if __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI
189  void *__e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
190  (void)__cxxabiv1::__cxa_init_primary_exception(
191  __e, const_cast<std::type_info*>(&typeid(__ex)),
192  __exception_ptr::__dest_thunk<_Ex>);
193  ::new (__e) _Ex(__ex);
194  return exception_ptr(__e);
195 #else
196  throw __ex;
197 #endif
198  }
199  catch(...)
200  {
201  return current_exception();
202  }
203 #else
204  return exception_ptr();
205 #endif
206  }
207 
208  // _GLIBCXX_RESOLVE_LIB_DEFECTS
209  // 1130. copy_exception name misleading
210  /// Obtain an exception_ptr pointing to a copy of the supplied object.
211  /// This function is deprecated, use std::make_exception_ptr instead.
212  template<typename _Ex>
214  copy_exception(_Ex __ex) _GLIBCXX_USE_NOEXCEPT _GLIBCXX_DEPRECATED;
215 
216  template<typename _Ex>
218  copy_exception(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
219  { return std::make_exception_ptr<_Ex>(__ex); }
220 
221  // @} group exceptions
222 } // namespace std
223 
224 } // extern "C++"
225 
226 #pragma GCC visibility pop
227 
228 #endif
An opaque pointer to an arbitrary exception.
Definition: exception_ptr.h:83
exception_ptr copy_exception(_Ex __ex) noexcept 1
Obtain an exception_ptr pointing to a copy of the supplied object. This function is deprecated...
void rethrow_exception(exception_ptr) __attribute__((__noreturn__))
Throw the object pointed to by the exception_ptr.
ISO C++ entities toplevel namespace is std.
exception_ptr make_exception_ptr(_Ex) noexcept
Obtain an exception_ptr pointing to a copy of the supplied object.
exception_ptr current_exception() noexcept
Part of RTTI.
Definition: typeinfo:88