libstdc++: exception Source File

libstdc++

exception
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1// Exception Handling support header for -*- C++ -*-
2
3// Copyright (C) 1995-2026 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#define __glibcxx_want_constexpr_exceptions
42#define __glibcxx_want_exception_ptr_cast
43#include <bits/version.h>
44
45extern "C++" {
46
47namespace std _GLIBCXX_VISIBILITY(default)
48{
49 /** @addtogroup exceptions
50 * @{
51 */
52
53 /** If an %exception is thrown which is not listed in a function's
54 * %exception specification, one of these may be thrown.
55 *
56 * @ingroup exceptions
57 */
58 class bad_exception : public exception
59 {
60 public:
61 _GLIBCXX26_CONSTEXPR bad_exception() _GLIBCXX_USE_NOEXCEPT { }
62
63#if __cplusplus >= 202400L
64 [[__gnu__::__gnu_inline__]]
65 constexpr inline virtual ~bad_exception() _GLIBCXX_TXN_SAFE_DYN noexcept {}
66
67 [[__gnu__::__gnu_inline__]]
68 constexpr inline virtual const char* what() const _GLIBCXX_TXN_SAFE_DYN
69 noexcept
70 {
71 return "std::bad_exception";
72 }
73#else
74 // This declaration is not useless:
75 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
76 virtual ~bad_exception() _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
77
78 // See comment in eh_exception.cc.
79 virtual const char*
80 what() const _GLIBCXX_TXN_SAFE_DYN _GLIBCXX_USE_NOEXCEPT;
81#endif
82 };
83
84 /// If you write a replacement %terminate handler, it must be of this type.
85 typedef void (*terminate_handler) ();
86
87 /// Takes a new handler function as an argument, returns the old function.
88 terminate_handler set_terminate(terminate_handler) _GLIBCXX_USE_NOEXCEPT;
89
90#if __cplusplus >= 201103L
91 /// Return the current terminate handler.
92 terminate_handler get_terminate() noexcept;
93#endif
94
95 /** The runtime will call this function if %exception handling must be
96 * abandoned for any reason. It can also be called by the user. */
97 void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__,__cold__));
98
99#if __cplusplus < 201703L || (__cplusplus <= 202002L && _GLIBCXX_USE_DEPRECATED)
100 /// If you write a replacement %unexpected handler, it must be of this type.
101 typedef void (*_GLIBCXX11_DEPRECATED unexpected_handler) ();
102
103 /** Takes a new handler function as an argument, returns the old function.
104 *
105 * @deprecated Removed from the C++ standard in C++17
106 */
107 _GLIBCXX11_DEPRECATED
108 unexpected_handler set_unexpected(unexpected_handler) _GLIBCXX_USE_NOEXCEPT;
109
110#if __cplusplus >= 201103L
111 /** Return the current unexpected handler.
112 *
113 * @since C++11
114 * @deprecated Removed from the C++ standard in C++17
115 */
116 _GLIBCXX11_DEPRECATED
117 unexpected_handler get_unexpected() noexcept;
118#endif
119
120 /** The runtime will call this function if an %exception is thrown which
121 * violates the function's %exception specification.
122 *
123 * @deprecated Removed from the C++ standard in C++17
124 */
125 _GLIBCXX11_DEPRECATED
126 void unexpected() __attribute__ ((__noreturn__,__cold__));
127#endif
128
129 /** [18.6.4]/1: 'Returns true after completing evaluation of a
130 * throw-expression until either completing initialization of the
131 * exception-declaration in the matching handler or entering `unexpected()`
132 * due to the throw; or after entering `terminate()` for any reason
133 * other than an explicit call to `terminate()`. [Note: This includes
134 * stack unwinding [15.2]. end note]'
135 *
136 * 2: 'When `uncaught_exception()` is true, throwing an
137 * %exception can result in a call of `terminate()`
138 * (15.5.1).
139 */
140 _GLIBCXX17_DEPRECATED_SUGGEST("std::uncaught_exceptions()")
141 bool uncaught_exception() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
142
143#ifdef __cpp_lib_uncaught_exceptions // C++ >= 17 || GNU++ >= 03
144 /** The number of uncaught exceptions.
145 * @since C++17, or any non-strict mode, e.g. `-std=gnu++98`
146 * @see uncaught_exception()
147 */
148 int uncaught_exceptions() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
149#endif
150
151 /// @} group exceptions
152} // namespace std
153
154namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
155{
156_GLIBCXX_BEGIN_NAMESPACE_VERSION
157
158 /**
159 * @brief A replacement for the standard terminate_handler which
160 * prints more information about the terminating exception (if any)
161 * on stderr.
162 *
163 * @ingroup exceptions
164 *
165 * Call
166 * @code
167 * std::set_terminate(__gnu_cxx::__verbose_terminate_handler)
168 * @endcode
169 * to use. For more info, see
170 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt02ch06s02.html
171 *
172 * In 3.4 and later, this is on by default.
173 */
174 void __verbose_terminate_handler();
175
176_GLIBCXX_END_NAMESPACE_VERSION
177} // namespace
178
179} // extern "C++"
180
181#if __cplusplus >= 201103L
182# include <bits/exception_ptr.h>
183# include <bits/nested_exception.h>
184#endif
185
186#endif
version.h
exception.h
exception_ptr.h
nested_exception.h
c++config.h
std::uncaught_exception
bool uncaught_exception() noexcept
std::terminate_handler
void(* terminate_handler)()
If you write a replacement terminate handler, it must be of this type.
Definition exception:85
std::get_terminate
terminate_handler get_terminate() noexcept
Return the current terminate handler.
std::set_terminate
terminate_handler set_terminate(terminate_handler) noexcept
Takes a new handler function as an argument, returns the old function.
std::terminate
void terminate() noexcept
__gnu_cxx::__verbose_terminate_handler
void __verbose_terminate_handler()
A replacement for the standard terminate_handler which prints more information about the terminating ...
std
ISO C++ entities toplevel namespace is std.
__gnu_cxx
GNU extensions for public use.
std::bad_exception
Definition exception:59
std::bad_exception::what
virtual constexpr const char * what() const noexcept
Definition exception:68