libstdc++
exception_ptr.h
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1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
2 
3 // Copyright (C) 2008-2019 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 extern "C++" {
43 
44 namespace std
45 {
46  class type_info;
47 
48  /**
49  * @addtogroup exceptions
50  * @{
51  */
52  namespace __exception_ptr
53  {
54  class exception_ptr;
55  }
56 
57  using __exception_ptr::exception_ptr;
58 
59  /** Obtain an exception_ptr to the currently handled exception. If there
60  * is none, or the currently handled exception is foreign, return the null
61  * value.
62  */
63  exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT;
64 
65  template<typename _Ex>
66  exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
67 
68  /// Throw the object pointed to by the exception_ptr.
69  void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
70 
71  namespace __exception_ptr
72  {
74 
75  /**
76  * @brief An opaque pointer to an arbitrary exception.
77  * @ingroup exceptions
78  */
80  {
81  void* _M_exception_object;
82 
83  explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
84 
85  void _M_addref() _GLIBCXX_USE_NOEXCEPT;
86  void _M_release() _GLIBCXX_USE_NOEXCEPT;
87 
88  void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
89 
90  friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
92  template<typename _Ex>
93  friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
94 
95  public:
96  exception_ptr() _GLIBCXX_USE_NOEXCEPT;
97 
98  exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
99 
100 #if __cplusplus >= 201103L
101  exception_ptr(nullptr_t) noexcept
102  : _M_exception_object(0)
103  { }
104 
105  exception_ptr(exception_ptr&& __o) noexcept
106  : _M_exception_object(__o._M_exception_object)
107  { __o._M_exception_object = 0; }
108 #endif
109 
110 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
111  typedef void (exception_ptr::*__safe_bool)();
112 
113  // For construction from nullptr or 0.
114  exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
115 #endif
116 
117  exception_ptr&
118  operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
119 
120 #if __cplusplus >= 201103L
121  exception_ptr&
122  operator=(exception_ptr&& __o) noexcept
123  {
124  exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
125  return *this;
126  }
127 #endif
128 
129  ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
130 
131  void
132  swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
133 
134 #ifdef _GLIBCXX_EH_PTR_COMPAT
135  // Retained for compatibility with CXXABI_1.3.
136  void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
137  __attribute__ ((__const__));
138  bool operator!() const _GLIBCXX_USE_NOEXCEPT
139  __attribute__ ((__pure__));
140  operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
141 #endif
142 
143 #if __cplusplus >= 201103L
144  explicit operator bool() const
145  { return _M_exception_object; }
146 #endif
147 
148  friend bool
149  operator==(const exception_ptr&, const exception_ptr&)
150  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
151 
152  const class std::type_info*
153  __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
154  __attribute__ ((__pure__));
155  };
156 
157  bool
158  operator==(const exception_ptr&, const exception_ptr&)
159  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
160 
161  bool
162  operator!=(const exception_ptr&, const exception_ptr&)
163  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
164 
165  inline void
166  swap(exception_ptr& __lhs, exception_ptr& __rhs)
167  { __lhs.swap(__rhs); }
168 
169  template<typename _Ex>
170  inline void
171  __dest_thunk(void* __x)
172  { static_cast<_Ex*>(__x)->~_Ex(); }
173 
174  } // namespace __exception_ptr
175 
176  /// Obtain an exception_ptr pointing to a copy of the supplied object.
177  template<typename _Ex>
178  exception_ptr
179  make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
180  {
181 #if __cpp_exceptions && __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI
182  void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
183  (void) __cxxabiv1::__cxa_init_primary_exception(
184  __e, const_cast<std::type_info*>(&typeid(__ex)),
185  __exception_ptr::__dest_thunk<_Ex>);
186  try
187  {
188  ::new (__e) _Ex(__ex);
189  return exception_ptr(__e);
190  }
191  catch(...)
192  {
193  __cxxabiv1::__cxa_free_exception(__e);
194  return current_exception();
195  }
196 #elif __cpp_exceptions
197  try
198  {
199  throw __ex;
200  }
201  catch(...)
202  {
203  return current_exception();
204  }
205 #else // no RTTI and no exceptions
206  return exception_ptr();
207 #endif
208  }
209 
210  // @} group exceptions
211 } // namespace std
212 
213 } // extern "C++"
214 
215 #pragma GCC visibility pop
216 
217 #endif
ISO C++ entities toplevel namespace is std.
void rethrow_exception(exception_ptr) __attribute__((__noreturn__))
Throw the object pointed to by the exception_ptr.
Part of RTTI.
Definition: typeinfo:88
exception_ptr current_exception() noexcept
exception_ptr make_exception_ptr(_Ex) noexcept
Obtain an exception_ptr pointing to a copy of the supplied object.
An opaque pointer to an arbitrary exception.
Definition: exception_ptr.h:79