1// Exception Handling support header for -*- C++ -*-
2
3// Copyright (C) 1995, 1996, 1997, 1998, 2000, 2001, 2002
4// Free Software Foundation
5//
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7//
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22
23// As a special exception, you may use this file as part of a free software
24// library without restriction.  Specifically, if other files instantiate
25// templates or use macros or inline functions from this file, or you compile
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30// the GNU General Public License.
31
32/** @file exception
33 *  This header defines several types and functions relating to the
34 *  handling of exceptions in a C++ program.
35 */
36
37#ifndef __EXCEPTION__
38#define __EXCEPTION__
39
40extern "C++" {
41
42namespace std
43{
44  /**
45   *  @brief Base class for all library exceptions.
46   *
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).
51   */
52  class exception
53  {
54  public:
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();
60  };
61
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
65  {
66  public:
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();
71  };
72
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) ();
77
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.  */
82  void terminate() __attribute__ ((__noreturn__));
83
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__));
89
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]"
96   *
97   *  2:  "When @c uncaught_exception() is true, throwing an %exception can
98   *  result in a call of @c terminate() (15.5.1)."
99   */
100  bool uncaught_exception() throw();
101} // namespace std
102
103namespace __gnu_cxx
104{
105  /** A replacement for the standard terminate_handler which prints more
106      information about the terminating exception (if any) on stderr.  Call
107      @code
108        std::set_terminate (__gnu_cxx::__verbose_terminate_handler)
109      @endcode
110      to use.  For more info, see
111      http://gcc.gnu.org/onlinedocs/libstdc++/19_diagnostics/howto.html#4
112  */
113  void __verbose_terminate_handler ();
114} // namespace __gnu_cxx
115
116} // extern "C++"
117
118#endif
119