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>
39#include <typeinfo>
40#include <new>
41
42#if __cplusplus >= 201103L
43# include <bits/move.h>
44#endif
45
46extern "C++" {
47
48namespace std
49{
50 class type_info;
51
52 /**
53 * @addtogroup exceptions
54 * @{
55 */
56
57 namespace __exception_ptr
58 {
59 class exception_ptr;
60 }
61
62 using __exception_ptr::exception_ptr;
63
64 /** Obtain an exception_ptr to the currently handled exception. If there
65 * is none, or the currently handled exception is foreign, return the null
66 * value.
67 */
69
72
73 /// Throw the object pointed to by the exception_ptr.
74 void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
75
76 namespace __exception_ptr
77 {
79
80 /**
81 * @brief An opaque pointer to an arbitrary exception.
82 * @ingroup exceptions
83 */
85 {
86 void* _M_exception_object;
87
88 explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
89
90 void _M_addref() _GLIBCXX_USE_NOEXCEPT;
91 void _M_release() _GLIBCXX_USE_NOEXCEPT;
92
93 void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
94
97 template<typename _Ex>
99
100 public:
102
104
105#if __cplusplus >= 201103L
107 : _M_exception_object(0)
108 { }
109
111 : _M_exception_object(__o._M_exception_object)
112 { __o._M_exception_object = 0; }
113#endif
114
115#if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
116 typedef void (exception_ptr::*__safe_bool)();
117
118 // For construction from nullptr or 0.
120#endif
121
123 operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
124
125#if __cplusplus >= 201103L
127 operator=(exception_ptr&& __o) noexcept
128 {
129 exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
130 return *this;
131 }
132#endif
133
135
136 void
138
139#ifdef _GLIBCXX_EH_PTR_COMPAT
140 // Retained for compatibility with CXXABI_1.3.
143 bool operator!() const _GLIBCXX_USE_NOEXCEPT
145 operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
146#endif
147
148#if __cplusplus >= 201103L
149 explicit operator bool() const
150 { return _M_exception_object; }
151#endif
152
153 friend bool
154 operator==(const exception_ptr&, const exception_ptr&)
156
157 const class std::type_info*
158 __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
160 };
161
162 /// @relates exception_ptr @{
163
164 bool
165 operator==(const exception_ptr&, const exception_ptr&)
167
168 bool
169 operator!=(const exception_ptr&, const exception_ptr&)
171
172 inline void
174 { __lhs.swap(__rhs); }
175
176 // @}
177
178 /// @cond undocumented
179 template<typename _Ex>
180 inline void
181 __dest_thunk(void* __x)
182 { static_cast<_Ex*>(__x)->~_Ex(); }
183 /// @endcond
184
185 } // namespace __exception_ptr
186
187 /// Obtain an exception_ptr pointing to a copy of the supplied object.
188 template<typename _Ex>
189 exception_ptr
191 {
192#if __cpp_exceptions && __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI \
193 && __cplusplus >= 201103L
194 using _Ex2 = typename remove_reference<_Ex>::type;
195 void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
196 (void) __cxxabiv1::__cxa_init_primary_exception(
197 __e, const_cast<std::type_info*>(&typeid(_Ex)),
198 __exception_ptr::__dest_thunk<_Ex2>);
199 try
200 {
201 ::new (__e) _Ex2(std::forward<_Ex>(__ex));
202 return exception_ptr(__e);
203 }
204 catch(...)
205 {
206 __cxxabiv1::__cxa_free_exception(__e);
207 return current_exception();
208 }
209#elif __cpp_exceptions
210 try
211 {
212 throw __ex;
213 }
214 catch(...)
215 {
216 return current_exception();
217 }
218#else // no RTTI and no exceptions
219 return exception_ptr();
220#endif
221 }
222
223 /// @} group exceptions
224} // namespace std
225
226} // extern "C++"
227
228#pragma GCC visibility pop
229
230#endif
exception_ptr current_exception() noexcept
exception_ptr make_exception_ptr(_Ex) noexcept
Obtain an exception_ptr pointing to a copy of the supplied object.
void rethrow_exception(exception_ptr)
Throw the object pointed to by the exception_ptr.
ISO C++ entities toplevel namespace is std.
Part of RTTI.
Definition typeinfo:89
An opaque pointer to an arbitrary exception.