libstdc++
exception_ptr.h
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1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
2 
3 // Copyright (C) 2008-2020 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 
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  template<typename _Ex>
67  exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
68 
69  /// Throw the object pointed to by the exception_ptr.
70  void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
71 
72  namespace __exception_ptr
73  {
75 
76  /**
77  * @brief An opaque pointer to an arbitrary exception.
78  * @ingroup exceptions
79  */
81  {
82  void* _M_exception_object;
83 
84  explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
85 
86  void _M_addref() _GLIBCXX_USE_NOEXCEPT;
87  void _M_release() _GLIBCXX_USE_NOEXCEPT;
88 
89  void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
90 
91  friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
93  template<typename _Ex>
94  friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
95 
96  public:
97  exception_ptr() _GLIBCXX_USE_NOEXCEPT;
98 
99  exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
100 
101 #if __cplusplus >= 201103L
102  exception_ptr(nullptr_t) noexcept
103  : _M_exception_object(0)
104  { }
105 
106  exception_ptr(exception_ptr&& __o) noexcept
107  : _M_exception_object(__o._M_exception_object)
108  { __o._M_exception_object = 0; }
109 #endif
110 
111 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
112  typedef void (exception_ptr::*__safe_bool)();
113 
114  // For construction from nullptr or 0.
115  exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
116 #endif
117 
118  exception_ptr&
119  operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
120 
121 #if __cplusplus >= 201103L
122  exception_ptr&
123  operator=(exception_ptr&& __o) noexcept
124  {
125  exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
126  return *this;
127  }
128 #endif
129 
130  ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
131 
132  void
133  swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
134 
135 #ifdef _GLIBCXX_EH_PTR_COMPAT
136  // Retained for compatibility with CXXABI_1.3.
137  void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
138  __attribute__ ((__const__));
139  bool operator!() const _GLIBCXX_USE_NOEXCEPT
140  __attribute__ ((__pure__));
141  operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
142 #endif
143 
144 #if __cplusplus >= 201103L
145  explicit operator bool() const
146  { return _M_exception_object; }
147 #endif
148 
149  friend bool
150  operator==(const exception_ptr&, const exception_ptr&)
151  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
152 
153  const class std::type_info*
154  __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
155  __attribute__ ((__pure__));
156  };
157 
158  /// @relates exception_ptr @{
159 
160  bool
161  operator==(const exception_ptr&, const exception_ptr&)
162  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
163 
164  bool
165  operator!=(const exception_ptr&, const exception_ptr&)
166  _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
167 
168  inline void
169  swap(exception_ptr& __lhs, exception_ptr& __rhs)
170  { __lhs.swap(__rhs); }
171 
172  // @}
173 
174  /// @cond undocumented
175  template<typename _Ex>
176  inline void
177  __dest_thunk(void* __x)
178  { static_cast<_Ex*>(__x)->~_Ex(); }
179  /// @endcond
180 
181  } // namespace __exception_ptr
182 
183  /// Obtain an exception_ptr pointing to a copy of the supplied object.
184  template<typename _Ex>
185  exception_ptr
186  make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
187  {
188 #if __cpp_exceptions && __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  try
194  {
195  ::new (__e) _Ex(__ex);
196  return exception_ptr(__e);
197  }
198  catch(...)
199  {
200  __cxxabiv1::__cxa_free_exception(__e);
201  return current_exception();
202  }
203 #elif __cpp_exceptions
204  try
205  {
206  throw __ex;
207  }
208  catch(...)
209  {
210  return current_exception();
211  }
212 #else // no RTTI and no exceptions
213  return exception_ptr();
214 #endif
215  }
216 
217  // @} group exceptions
218 } // namespace std
219 
220 } // extern "C++"
221 
222 #pragma GCC visibility pop
223 
224 #endif
std::type_info
Part of RTTI.
Definition: typeinfo:88
std
ISO C++ entities toplevel namespace is std.
typeinfo
c++config.h
std::current_exception
exception_ptr current_exception() noexcept
std::__exception_ptr::exception_ptr
An opaque pointer to an arbitrary exception.
Definition: exception_ptr.h:80
std::make_exception_ptr
exception_ptr make_exception_ptr(_Ex) noexcept
Obtain an exception_ptr pointing to a copy of the supplied object.
Definition: exception_ptr.h:186
new
std::rethrow_exception
void rethrow_exception(exception_ptr)
Throw the object pointed to by the exception_ptr.
exception_defines.h
cxxabi_init_exception.h