# typeinfo

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    00001 // RTTI support for -*- C++ -*-
    00002 // Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
    00003 // 2003, 2004, 2005, 2006, 2007
    00004 // Free Software Foundation
    00005 //
    00006 // This file is part of GCC.
    00007 //
    00008 // GCC is free software; you can redistribute it and/or modify
    00009 // it under the terms of the GNU General Public License as published by
    00010 // the Free Software Foundation; either version 2, or (at your option)
    00011 // any later version.
    00012 //
    00013 // GCC is distributed in the hope that it will be useful,
    00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00016 // GNU General Public License for more details.
    00017 //
    00018 // You should have received a copy of the GNU General Public License
    00019 // along with GCC; see the file COPYING.  If not, write to
    00020 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
    00021 // Boston, MA 02110-1301, USA.
    00022
    00023 // As a special exception, you may use this file as part of a free software
    00024 // library without restriction.  Specifically, if other files instantiate
    00025 // templates or use macros or inline functions from this file, or you compile
    00026 // this file and link it with other files to produce an executable, this
    00027 // file does not by itself cause the resulting executable to be covered by
    00028 // the GNU General Public License.  This exception does not however
    00029 // invalidate any other reasons why the executable file might be covered by
    00030 // the GNU General Public License.
    00031
    00032 /** @file typeinfo
    00033  *  This is a Standard C++ Library header.
    00034  */
    00035
    00036 #ifndef _TYPEINFO
    00037 #define _TYPEINFO
    00038
    00039 #include <exception>
    00040
    00041 #pragma GCC visibility push(default)
    00042
    00043 extern "C++" {
    00044
    00045 namespace __cxxabiv1
    00046 {
    00047   class __class_type_info;
    00048 } // namespace __cxxabiv1
    00049
    00050 // Determine whether typeinfo names for the same type are merged (in which
    00051 // case comparison can just compare pointers) or not (in which case
    00052 // strings must be compared and g++.dg/abi/local1.C will fail), and
    00053 // whether comparison is to be implemented inline or not.  By default we
    00054 // use inline pointer comparison if weak symbols are available, and
    00055 // out-of-line strcmp if not.  Out-of-line pointer comparison is used
    00056 // where the object files are to be portable to multiple systems, some of
    00057 // which may not be able to use pointer comparison, but the particular
    00058 // system for which libstdc++ is being built can use pointer comparison;
    00059 // in particular for most ARM EABI systems, where the ABI specifies
    00060 // out-of-line comparison.  Inline strcmp is not currently supported.  The
    00061 // compiler's target configuration can override the defaults by defining
    00062 // __GXX_TYPEINFO_EQUALITY_INLINE to 1 or 0 to indicate whether or not
    00063 // comparison is inline, and __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to
    00064 // indicate whether or not pointer comparison can be used.
    00065
    00066 #ifndef __GXX_MERGED_TYPEINFO_NAMES
    00067   #if !__GXX_WEAK__
    00068     // If weak symbols are not supported, typeinfo names are not merged.
    00069     #define __GXX_MERGED_TYPEINFO_NAMES 0
    00070   #else
    00071     // On platforms that support weak symbols, typeinfo names are merged.
    00072     #define __GXX_MERGED_TYPEINFO_NAMES 1
    00073   #endif
    00074 #endif
    00075
    00076 // By default follow the same rules as for __GXX_MERGED_TYPEINFO_NAMES.
    00077 #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
    00078   #if !__GXX_WEAK__
    00079     #define __GXX_TYPEINFO_EQUALITY_INLINE 0
    00080   #else
    00081     #define __GXX_TYPEINFO_EQUALITY_INLINE 1
    00082   #endif
    00083 #endif
    00084
    00085 namespace std
    00086 {
    00087   /**
    00088    *  @brief  Part of RTTI.
    00089    *
    00090    *  The @c type_info class describes type information generated by
    00091    *  an implementation.
    00092   */
    00093   class type_info
    00094   {
    00095   public:
    00096     /** Destructor first. Being the first non-inline virtual function, this
    00097      *  controls in which translation unit the vtable is emitted. The
    00098      *  compiler makes use of that information to know where to emit
    00099      *  the runtime-mandated type_info structures in the new-abi.  */
    00100     virtual ~type_info();
    00101
    00102     /** Returns an @e implementation-defined byte string; this is not
    00103      *  portable between compilers!  */
    00104     const char* name() const
    00105     { return __name; }
    00106
    00107 #if !__GXX_TYPEINFO_EQUALITY_INLINE
    00108     bool before(const type_info& __arg) const;
    00109
    00110     // In old abi, or when weak symbols are not supported, there can
    00111     // be multiple instances of a type_info object for one
    00112     // type. Uniqueness must use the _name value, not object address.
    00113     bool operator==(const type_info& __arg) const;
    00114 #else
    00115   #if !__GXX_MERGED_TYPEINFO_NAMES
    00116     #error "Inline implementation of type_info comparision requires merging of type_info objects"
    00117   #endif
    00118     /** Returns true if @c *this precedes @c __arg in the implementation's
    00119      *  collation order.  */
    00120     // In new abi we can rely on type_info's NTBS being unique,
    00121     // and therefore address comparisons are sufficient.
    00122     bool before(const type_info& __arg) const
    00123     { return __name < __arg.__name; }
    00124
    00125     bool operator==(const type_info& __arg) const
    00126     { return __name == __arg.__name; }
    00127 #endif
    00128     bool operator!=(const type_info& __arg) const
    00129     { return !operator==(__arg); }
    00130
    00131     // Return true if this is a pointer type of some kind
    00132     virtual bool __is_pointer_p() const;
    00133
    00134     // Return true if this is a function type
    00135     virtual bool __is_function_p() const;
    00136
    00137     // Try and catch a thrown type. Store an adjusted pointer to the
    00138     // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
    00139     // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
    00140     // type, then THR_OBJ is the pointer itself. OUTER indicates the
    00141     // number of outer pointers, and whether they were const
    00142     // qualified.
    00143     virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
    00144                 unsigned __outer) const;
    00145
    00146     // Internally used during catch matching
    00147     virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
    00148                  void **__obj_ptr) const;
    00149
    00150   protected:
    00151     const char *__name;
    00152
    00153     explicit type_info(const char *__n): __name(__n) { }
    00154
    00155   private:
    00156     /// Assigning type_info is not supported.
    00157     type_info& operator=(const type_info&);
    00158     type_info(const type_info&);
    00159   };
    00160
    00161   /**
    00162    *  @brief  Thrown during incorrect typecasting.
    00163    *
    00164    *  If you attempt an invalid @c dynamic_cast expression, an instance of
    00165    *  this class (or something derived from this class) is thrown.  */
    00166   class bad_cast : public exception
    00167   {
    00168   public:
    00169     bad_cast() throw() { }
    00170
    00171     // This declaration is not useless:
    00172     // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
    00173     virtual ~bad_cast() throw();
    00174
    00175     // See comment in eh_exception.cc.
    00176     virtual const char* what() const throw();
    00177   };
    00178
    00179   /** If you use a NULL pointer in a @c typeid expression, this is thrown.  */
    00180   class bad_typeid : public exception
    00181   {
    00182   public:
    00183     bad_typeid () throw() { }
    00184
    00185     // This declaration is not useless:
    00186     // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
    00187     virtual ~bad_typeid() throw();
    00188
    00189     // See comment in eh_exception.cc.
    00190     virtual const char* what() const throw();
    00191   };
    00192 } // namespace std
    00193
    00194 #pragma GCC visibility pop
    00195
    00196 } // extern "C++"
    00197 #endif