libstdc++
exception
Go to the documentation of this file.
1 // Exception Handling support header for -*- C++ -*-
2 
3 // Copyright (C) 1995-2025 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 exception
27  * This is a Standard C++ Library header.
28  */
29 
30 #ifndef __EXCEPTION__
31 #define __EXCEPTION__
32 
33 #ifdef _GLIBCXX_SYSHDR
34 #pragma GCC system_header
35 #endif
36 
37 #include <bits/c++config.h>
38 #include <bits/exception.h>
39 
40 #define __glibcxx_want_uncaught_exceptions
41 #include <bits/version.h>
42 
43 extern "C++" {
44 
45 namespace std _GLIBCXX_VISIBILITY(default)
46 {
47  /** @addtogroup exceptions
48  * @{
49  */
50 
51  /** If an %exception is thrown which is not listed in a function's
52  * %exception specification, one of these may be thrown.
53  *
54  * @ingroup exceptions
55  */
56  class bad_exception : public exception
57  {
58  public:
59  bad_exception() _GLIBCXX_USE_NOEXCEPT { }
60 
61  // This declaration is not useless:
62  // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
63  virtual ~bad_exception() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
64 
65  // See comment in eh_exception.cc.
66  virtual const char*
67  what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
68  };
69 
70  /// If you write a replacement %terminate handler, it must be of this type.
71  typedef void (*terminate_handler) ();
72 
73  /// Takes a new handler function as an argument, returns the old function.
74  terminate_handler set_terminate(terminate_handler) _GLIBCXX_USE_NOEXCEPT;
75 
76 #if __cplusplus >= 201103L
77  /// Return the current terminate handler.
78  terminate_handler get_terminate() noexcept;
79 #endif
80 
81  /** The runtime will call this function if %exception handling must be
82  * abandoned for any reason. It can also be called by the user. */
83  void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__,__cold__));
84 
85 #if __cplusplus < 201703L || (__cplusplus <= 202002L && _GLIBCXX_USE_DEPRECATED)
86  /// If you write a replacement %unexpected handler, it must be of this type.
87  typedef void (*_GLIBCXX11_DEPRECATED unexpected_handler) ();
88 
89  /** Takes a new handler function as an argument, returns the old function.
90  *
91  * @deprecated Removed from the C++ standard in C++17
92  */
93  _GLIBCXX11_DEPRECATED
94  unexpected_handler set_unexpected(unexpected_handler) _GLIBCXX_USE_NOEXCEPT;
95 
96 #if __cplusplus >= 201103L
97  /** Return the current unexpected handler.
98  *
99  * @since C++11
100  * @deprecated Removed from the C++ standard in C++17
101  */
102  _GLIBCXX11_DEPRECATED
103  unexpected_handler get_unexpected() noexcept;
104 #endif
105 
106  /** The runtime will call this function if an %exception is thrown which
107  * violates the function's %exception specification.
108  *
109  * @deprecated Removed from the C++ standard in C++17
110  */
111  _GLIBCXX11_DEPRECATED
112  void unexpected() __attribute__ ((__noreturn__,__cold__));
113 #endif
114 
115  /** [18.6.4]/1: 'Returns true after completing evaluation of a
116  * throw-expression until either completing initialization of the
117  * exception-declaration in the matching handler or entering `unexpected()`
118  * due to the throw; or after entering `terminate()` for any reason
119  * other than an explicit call to `terminate()`. [Note: This includes
120  * stack unwinding [15.2]. end note]'
121  *
122  * 2: 'When `uncaught_exception()` is true, throwing an
123  * %exception can result in a call of 1terminate()`
124  * (15.5.1).'
125  */
126  _GLIBCXX17_DEPRECATED_SUGGEST("std::uncaught_exceptions()")
127  bool uncaught_exception() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
128 
129 #ifdef __cpp_lib_uncaught_exceptions // C++ >= 17 || GNU++ >= 03
130  /** The number of uncaught exceptions.
131  * @since C++17, or any non-strict mode, e.g. `-std=gnu++98`
132  * @see uncaught_exception()
133  */
134  int uncaught_exceptions() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
135 #endif
136 
137  /// @} group exceptions
138 } // namespace std
139 
140 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
141 {
142 _GLIBCXX_BEGIN_NAMESPACE_VERSION
143 
144  /**
145  * @brief A replacement for the standard terminate_handler which
146  * prints more information about the terminating exception (if any)
147  * on stderr.
148  *
149  * @ingroup exceptions
150  *
151  * Call
152  * @code
153  * std::set_terminate(__gnu_cxx::__verbose_terminate_handler)
154  * @endcode
155  * to use. For more info, see
156  * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt02ch06s02.html
157  *
158  * In 3.4 and later, this is on by default.
159  */
160  void __verbose_terminate_handler();
161 
162 _GLIBCXX_END_NAMESPACE_VERSION
163 } // namespace
164 
165 } // extern "C++"
166 
167 #if (__cplusplus >= 201103L)
168 #include <bits/exception_ptr.h>
169 #include <bits/nested_exception.h>
170 #endif
171 
172 #endif