libstdc++-v3/libsupc++/tinfo.cc

   1 // Methods for type_info for -*- C++ -*- Run Time Type Identification.
   2 // Copyright (C) 1994-2024 Free Software Foundation, Inc.
   3 //
   4 // This file is part of GCC.
   5 //
   6 // GCC is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // GCC is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <bits/c++config.h>
  26 #include <cstddef>
  27 #include "tinfo.h"
  28
  29 std::type_info::
  30 ~type_info ()
  31 { }
  32
  33 #if !__GXX_TYPEINFO_EQUALITY_INLINE
  34
  35 #if __cplusplus > 202002L
  36 # error "this file must be compiled with C++20 or older to define operator=="
  37 #endif
  38
  39 // We can't rely on common symbols being shared between shared objects.
  40 bool std::type_info::
  41 operator== (const std::type_info& arg) const _GLIBCXX_NOEXCEPT
  42 {
  43 #if __GXX_MERGED_TYPEINFO_NAMES
  44   return name () == arg.name ();
  45 #else
  46   /* The name() method will strip any leading '*' prefix. Therefore
  47      take care to look at __name rather than name() when looking for
  48      the "pointer" prefix.  */
  49   return (&arg == this)
  50     || (__name[0] != '*' && (__builtin_strcmp (name (), arg.name ()) == 0));
  51 #endif
  52 }
  53
  54 bool
  55 std::type_info::__equal (const std::type_info& arg) const _GLIBCXX_NOEXCEPT
  56 __attribute__((alias("_ZNKSt9type_infoeqERKS_")));
  57 #endif
  58
  59 namespace std {
  60
  61 // return true if this is a type_info for a pointer type
  62 bool type_info::
  63 __is_pointer_p () const
  64 {
  65   return false;
  66 }
  67
  68 // return true if this is a type_info for a function type
  69 bool type_info::
  70 __is_function_p () const
  71 {
  72   return false;
  73 }
  74
  75 // try and catch a thrown object.
  76 bool type_info::
  77 __do_catch (const type_info *thr_type, void **, unsigned) const
  78 {
  79   return *this == *thr_type;
  80 }
  81
  82 // upcast from this type to the target. __class_type_info will override
  83 bool type_info::
  84 __do_upcast (const abi::__class_type_info *, void **) const
  85 {
  86   return false;
  87 }
  88
  89 }