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>
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 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
122 operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
123
124#if __cplusplus >= 201103L
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>
182 exception_ptr
183 make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
184 {
185#if __cpp_exceptions && __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI \
186 && __cplusplus >= 201103L
187 using _Ex2 = typename remove_reference<_Ex>::type;
188 void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
189 (void) __cxxabiv1::__cxa_init_primary_exception(
190 __e, const_cast<std::type_info*>(&typeid(_Ex)),
191 __exception_ptr::__dest_thunk<_Ex2>);
192 try
193 {
194 ::new (__e) _Ex2(std::forward<_Ex>(__ex));
195 return exception_ptr(__e);
196 }
197 catch(...)
198 {
199 __cxxabiv1::__cxa_free_exception(__e);
200 return current_exception();
201 }
202#elif __cpp_exceptions
203 try
204 {
205 throw __ex;
206 }
207 catch(...)
208 {
209 return current_exception();
210 }
211#else // no RTTI and no exceptions
212 return exception_ptr();
213#endif
214 }
215
216 /// @} group exceptions
217} // namespace std
218
219} // extern "C++"
220
221#pragma GCC visibility pop
222
223#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) __attribute__((__noreturn__))
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:84