1 // Exception Handling support header (exception_ptr class) for -*- C++ -*- 2 3 // Copyright (C) 2008-2018 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> 38 #include <bits/cxxabi_init_exception.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 { 73 using std::rethrow_exception; 74 75 /** 76 * @brief An opaque pointer to an arbitrary exception. 77 * @ingroup exceptions 78 */ 79 class exception_ptr 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; 91 friend void std::rethrow_exception(exception_ptr); 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 218