# 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, 2009
    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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
    00019 // permissions described in the GCC Runtime Library Exception, version
    00020 // 3.1, as published by the Free Software Foundation.
    00021
    00022 // You should have received a copy of the GNU General Public License and
    00023 // a copy of the GCC Runtime Library Exception along with this program;
    00024 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    00025 // <http://www.gnu.org/licenses/>.
    00026
    00027 /** @file typeinfo
    00028  *  This is a Standard C++ Library header.
    00029  */
    00030
    00031 #ifndef _TYPEINFO
    00032 #define _TYPEINFO
    00033
    00034 #include <exception>
    00035
    00036 #pragma GCC visibility push(default)
    00037
    00038 extern "C++" {
    00039
    00040 namespace __cxxabiv1
    00041 {
    00042   class __class_type_info;
    00043 } // namespace __cxxabiv1
    00044
    00045 // Determine whether typeinfo names for the same type are merged (in which
    00046 // case comparison can just compare pointers) or not (in which case
    00047 // strings must be compared and g++.dg/abi/local1.C will fail), and
    00048 // whether comparison is to be implemented inline or not.  By default we
    00049 // use inline pointer comparison if weak symbols are available, and
    00050 // out-of-line strcmp if not.  Out-of-line pointer comparison is used
    00051 // where the object files are to be portable to multiple systems, some of
    00052 // which may not be able to use pointer comparison, but the particular
    00053 // system for which libstdc++ is being built can use pointer comparison;
    00054 // in particular for most ARM EABI systems, where the ABI specifies
    00055 // out-of-line comparison.  Inline strcmp is not currently supported.  The
    00056 // compiler's target configuration can override the defaults by defining
    00057 // __GXX_TYPEINFO_EQUALITY_INLINE to 1 or 0 to indicate whether or not
    00058 // comparison is inline, and __GXX_MERGED_TYPEINFO_NAMES to 1 or 0 to
    00059 // indicate whether or not pointer comparison can be used.
    00060
    00061 #ifndef __GXX_MERGED_TYPEINFO_NAMES
    00062   #if !__GXX_WEAK__
    00063     // If weak symbols are not supported, typeinfo names are not merged.
    00064     #define __GXX_MERGED_TYPEINFO_NAMES 0
    00065   #else
    00066     // On platforms that support weak symbols, typeinfo names are merged.
    00067     #define __GXX_MERGED_TYPEINFO_NAMES 1
    00068   #endif
    00069 #endif
    00070
    00071 // By default follow the same rules as for __GXX_MERGED_TYPEINFO_NAMES.
    00072 #ifndef __GXX_TYPEINFO_EQUALITY_INLINE
    00073   #if !__GXX_WEAK__
    00074     #define __GXX_TYPEINFO_EQUALITY_INLINE 0
    00075   #else
    00076     #define __GXX_TYPEINFO_EQUALITY_INLINE 1
    00077   #endif
    00078 #endif
    00079
    00080 namespace std
    00081 {
    00082   /**
    00083    *  @brief  Part of RTTI.
    00084    *
    00085    *  The @c type_info class describes type information generated by
    00086    *  an implementation.
    00087   */
    00088   class type_info
    00089   {
    00090   public:
    00091     /** Destructor first. Being the first non-inline virtual function, this
    00092      *  controls in which translation unit the vtable is emitted. The
    00093      *  compiler makes use of that information to know where to emit
    00094      *  the runtime-mandated type_info structures in the new-abi.  */
    00095     virtual ~type_info();
    00096
    00097     /** Returns an @e implementation-defined byte string; this is not
    00098      *  portable between compilers!  */
    00099     const char* name() const
    00100     { return __name; }
    00101
    00102 #if !__GXX_TYPEINFO_EQUALITY_INLINE
    00103     bool before(const type_info& __arg) const;
    00104
    00105     // In old abi, or when weak symbols are not supported, there can
    00106     // be multiple instances of a type_info object for one
    00107     // type. Uniqueness must use the _name value, not object address.
    00108     bool operator==(const type_info& __arg) const;
    00109 #else
    00110   #if !__GXX_MERGED_TYPEINFO_NAMES
    00111     #error "Inline implementation of type_info comparision requires merging of type_info objects"
    00112   #endif
    00113     /** Returns true if @c *this precedes @c __arg in the implementation's
    00114      *  collation order.  */
    00115     // In new abi we can rely on type_info's NTBS being unique,
    00116     // and therefore address comparisons are sufficient.
    00117     bool before(const type_info& __arg) const
    00118     { return __name < __arg.__name; }
    00119
    00120     bool operator==(const type_info& __arg) const
    00121     { return __name == __arg.__name; }
    00122 #endif
    00123     bool operator!=(const type_info& __arg) const
    00124     { return !operator==(__arg); }
    00125
    00126     // Return true if this is a pointer type of some kind
    00127     virtual bool __is_pointer_p() const;
    00128
    00129     // Return true if this is a function type
    00130     virtual bool __is_function_p() const;
    00131
    00132     // Try and catch a thrown type. Store an adjusted pointer to the
    00133     // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
    00134     // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
    00135     // type, then THR_OBJ is the pointer itself. OUTER indicates the
    00136     // number of outer pointers, and whether they were const
    00137     // qualified.
    00138     virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
    00139                 unsigned __outer) const;
    00140
    00141     // Internally used during catch matching
    00142     virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
    00143                  void **__obj_ptr) const;
    00144
    00145   protected:
    00146     const char *__name;
    00147
    00148     explicit type_info(const char *__n): __name(__n) { }
    00149
    00150   private:
    00151     /// Assigning type_info is not supported.
    00152     type_info& operator=(const type_info&);
    00153     type_info(const type_info&);
    00154   };
    00155
    00156   /**
    00157    *  @brief  Thrown during incorrect typecasting.
    00158    *  @ingroup exceptions
    00159    *
    00160    *  If you attempt an invalid @c dynamic_cast expression, an instance of
    00161    *  this class (or something derived from this class) is thrown.  */
    00162   class bad_cast : public exception
    00163   {
    00164   public:
    00165     bad_cast() throw() { }
    00166
    00167     // This declaration is not useless:
    00168     // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
    00169     virtual ~bad_cast() throw();
    00170
    00171     // See comment in eh_exception.cc.
    00172     virtual const char* what() const throw();
    00173   };
    00174
    00175   /**
    00176    *  @brief Thrown when a NULL pointer in a @c typeid expression is used.
    00177    *  @ingroup exceptions
    00178    */
    00179   class bad_typeid : public exception
    00180   {
    00181   public:
    00182     bad_typeid () throw() { }
    00183
    00184     // This declaration is not useless:
    00185     // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
    00186     virtual ~bad_typeid() throw();
    00187
    00188     // See comment in eh_exception.cc.
    00189     virtual const char* what() const throw();
    00190   };
    00191 } // namespace std
    00192
    00193 #pragma GCC visibility pop
    00194
    00195 } // extern "C++"
    00196 #endif