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
42extern "C++" {
43
44namespace 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
119 operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
120
121#if __cplusplus >= 201103L
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
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.
Definition: exception_ptr.h:81