1 // Exception Handling support header for -*- C++ -*-
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24 // library without restriction. Specifically, if other files instantiate
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33 * This header defines several types and functions relating to the
34 * handling of exceptions in a C++ program.
45 * @brief Base class for all library exceptions.
47 * This is the base class for all exceptions thrown by the standard
48 * library, and by certain language expressions. You are free to derive
49 * your own %exception classes, or use a different hierarchy, or to
50 * throw non-class data (e.g., fundamental types).
55 exception() throw() { }
56 virtual ~exception() throw();
57 /** Returns a C-style character string describing the general cause
58 * of the current error. */
59 virtual const char* what() const throw();
62 /** If an %exception is thrown which is not listed in a function's
63 * %exception specification, one of these may be thrown. */
64 class bad_exception : public exception
67 bad_exception() throw() { }
68 // This declaration is not useless:
69 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
70 virtual ~bad_exception() throw();
73 /// If you write a replacement %terminate handler, it must be of this type.
74 typedef void (*terminate_handler) ();
75 /// If you write a replacement %unexpected handler, it must be of this type.
76 typedef void (*unexpected_handler) ();
78 /// Takes a new handler function as an argument, returns the old function.
79 terminate_handler set_terminate(terminate_handler) throw();
80 /** The runtime will call this function if %exception handling must be
81 * abandoned for any reason. It can also be called by the user. */
82 void terminate() __attribute__ ((__noreturn__));
84 /// Takes a new handler function as an argument, returns the old function.
85 unexpected_handler set_unexpected(unexpected_handler) throw();
86 /** The runtime will call this function if an %exception is thrown which
87 * violates the function's %exception specification. */
88 void unexpected() __attribute__ ((__noreturn__));
90 /** [18.6.4]/1: "Returns true after completing evaluation of a
91 * throw-expression until either completing initialization of the
92 * exception-declaration in the matching handler or entering @c unexpected()
93 * due to the throw; or after entering @c terminate() for any reason
94 * other than an explicit call to @c terminate(). [Note: This includes
95 * stack unwinding [15.2]. end note]"
97 * 2: "When @c uncaught_exception() is true, throwing an %exception can
98 * result in a call of @c terminate() (15.5.1)."
100 bool uncaught_exception() throw();
105 /** A replacement for the standard terminate_handler which prints more
106 information about the terminating exception (if any) on stderr. Call
108 std::set_terminate (__gnu_cxx::__verbose_terminate_handler)
110 to use. For more info, see
111 http://gcc.gnu.org/onlinedocs/libstdc++/19_diagnostics/howto.html#4
113 In 3.4 and later, this is on by default.
115 void __verbose_terminate_handler ();
116 } // namespace __gnu_cxx