typeinfo revision 117397 
1// RTTI support for -*- C++ -*-
2// Copyright (C) 1994, 1995, 1996, 1997, 1998, 2000, 2001, 2002
3// Free Software Foundation
4//
5// This file is part of GNU CC.
6//
7// GNU CC 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 2, or (at your option)
10// any later version.
11// 
12// GNU CC 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// You should have received a copy of the GNU General Public License
18// along with GNU CC; see the file COPYING.  If not, write to
19// the Free Software Foundation, 59 Temple Place - Suite 330,
20// Boston, MA 02111-1307, USA.
21
22// As a special exception, you may use this file as part of a free software
23// library without restriction.  Specifically, if other files instantiate
24// templates or use macros or inline functions from this file, or you compile
25// this file and link it with other files to produce an executable, this
26// file does not by itself cause the resulting executable to be covered by
27// the GNU General Public License.  This exception does not however
28// invalidate any other reasons why the executable file might be covered by
29// the GNU General Public License.
30
31/** @file typeinfo
32 *  This header provides RTTI support.
33 */
34
35#ifndef __TYPEINFO__
36#define __TYPEINFO__
37
38#include <exception>
39
40extern "C++" {
41
42namespace __cxxabiv1
43{
44  class __class_type_info;
45} // namespace __cxxabiv1
46
47#if !__GXX_WEAK__
48  // If weak symbols are not supported, typeinfo names are not merged.
49  #define __GXX_MERGED_TYPEINFO_NAMES 0
50#else
51  // On platforms that support weak symbols, typeinfo names are merged.
52  #define __GXX_MERGED_TYPEINFO_NAMES 1
53#endif
54
55namespace std 
56{
57  /**
58   *  @brief  Part of RTTI.
59   *
60   *  The @c type_info class describes type information generated by
61   *  an implementation.
62  */
63  class type_info 
64  {
65  public:
66    /** Destructor. Being the first non-inline virtual function, this
67     *  controls in which translation unit the vtable is emitted. The
68     *  compiler makes use of that information to know where to emit
69     *  the runtime-mandated type_info structures in the new-abi.  */
70    virtual ~type_info();
71
72  private:
73    /// Assigning type_info is not supported.  Made private.
74    type_info& operator=(const type_info&);
75    type_info(const type_info&);
76    
77  protected:
78    const char *__name;
79    
80  protected:
81    explicit type_info(const char *__n): __name(__n) { }
82    
83  public:
84    // the public interface
85    /** Returns an @e implementation-defined byte string; this is not
86     *  portable between compilers!  */
87    const char* name() const
88    { return __name; }
89
90#if !__GXX_MERGED_TYPEINFO_NAMES
91    bool before(const type_info& __arg) const;
92    // In old abi, or when weak symbols are not supported, there can
93    // be multiple instances of a type_info object for one
94    // type. Uniqueness must use the _name value, not object address.
95    bool operator==(const type_info& __arg) const;
96#else
97    /** Returns true if @c *this precedes @c __arg in the implementation's
98     *  collation order.  */
99    // In new abi we can rely on type_info's NTBS being unique,
100    // and therefore address comparisons are sufficient.
101    bool before(const type_info& __arg) const
102    { return __name < __arg.__name; }
103    bool operator==(const type_info& __arg) const
104    { return __name == __arg.__name; }
105#endif
106    bool operator!=(const type_info& __arg) const
107    { return !operator==(__arg); }
108    
109    // the internal interface
110  public:
111    // return true if this is a pointer type of some kind
112    virtual bool __is_pointer_p() const;
113    // return true if this is a function type
114    virtual bool __is_function_p() const;
115
116    // Try and catch a thrown type. Store an adjusted pointer to the
117    // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
118    // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
119    // type, then THR_OBJ is the pointer itself. OUTER indicates the
120    // number of outer pointers, and whether they were const
121    // qualified.
122    virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
123			    unsigned __outer) const;
124
125    // internally used during catch matching
126    virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
127			     void **__obj_ptr) const;
128  };
129
130  /**
131   *  @brief  Thrown during incorrect typecasting.
132   *
133   *  If you attempt an invalid @c dynamic_cast expression, an instance of
134   *  this class (or something derived from this class) is thrown.  */
135  class bad_cast : public exception 
136  {
137  public:
138    bad_cast() throw() { }
139    // This declaration is not useless:
140    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
141    virtual ~bad_cast() throw();
142  };
143  
144  /** If you use a NULL pointer in a @c typeid expression, this is thrown.  */
145  class bad_typeid : public exception 
146  {
147  public:
148    bad_typeid () throw() { }
149    // This declaration is not useless:
150    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
151    virtual ~bad_typeid() throw();
152  };
153} // namespace std
154
155} // extern "C++"
156#endif
157