libstdc++: typeindex Source File

libstdc++

typeindex
Go to the documentation of this file.
1// C++11 <typeindex> -*- C++ -*-
2
3// Copyright (C) 2010-2026 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library 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/** @file include/typeindex
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_TYPEINDEX
30#define _GLIBCXX_TYPEINDEX 1
31
32#ifdef _GLIBCXX_SYSHDR
33#pragma GCC system_header
34#endif
35
36#if __cplusplus < 201103L
37# include <bits/c++0x_warning.h>
38#else
39
40#include <typeinfo>
41#if __cplusplus > 201703L
42# include <compare>
43#endif
44
45namespace std _GLIBCXX_VISIBILITY(default)
46{
47_GLIBCXX_BEGIN_NAMESPACE_VERSION
48
49 /**
50 * @brief Class type_index
51 * @ingroup utilities
52 *
53 * The class type_index provides a simple wrapper for type_info
54 * which can be used as an index type in associative containers
55 * (23.6) and in unordered associative containers (23.7).
56 */
57 struct type_index
58 {
59 type_index(const type_info& __rhs) noexcept
60 : _M_target(&__rhs) { }
61
62 bool
63 operator==(const type_index& __rhs) const noexcept
64 { return *_M_target == *__rhs._M_target; }
65
66#if ! __cpp_lib_three_way_comparison
67 bool
68 operator!=(const type_index& __rhs) const noexcept
69 { return *_M_target != *__rhs._M_target; }
70#endif
71
72 bool
73 operator<(const type_index& __rhs) const noexcept
74 { return _M_target->before(*__rhs._M_target); }
75
76 bool
77 operator<=(const type_index& __rhs) const noexcept
78 { return !__rhs._M_target->before(*_M_target); }
79
80 bool
81 operator>(const type_index& __rhs) const noexcept
82 { return __rhs._M_target->before(*_M_target); }
83
84 bool
85 operator>=(const type_index& __rhs) const noexcept
86 { return !_M_target->before(*__rhs._M_target); }
87
88#if __cpp_lib_three_way_comparison
89 strong_ordering
90 operator<=>(const type_index& __rhs) const noexcept
91 {
92 if (*_M_target == *__rhs._M_target)
93 return strong_ordering::equal;
94 if (_M_target->before(*__rhs._M_target))
95 return strong_ordering::less;
96 return strong_ordering::greater;
97 }
98#endif
99
100 size_t
101 hash_code() const noexcept
102 { return _M_target->hash_code(); }
103
104 const char*
105 name() const noexcept
106 { return _M_target->name(); }
107
108 private:
109 const type_info* _M_target;
110 };
111
112 template<typename _Tp> struct hash;
113
114 /// std::hash specialization for type_index.
115 template<>
116 struct hash<type_index>
117 {
118 typedef size_t result_type;
119 typedef type_index argument_type;
120
121 size_t
122 operator()(const type_index& __ti) const noexcept
123 { return __ti.hash_code(); }
124 };
125
126_GLIBCXX_END_NAMESPACE_VERSION
127} // namespace std
128
129#endif // C++11
130
131#endif // _GLIBCXX_TYPEINDEX
compare
typeinfo
c++0x_warning.h
std
ISO C++ entities toplevel namespace is std.
std::type_info
Part of RTTI.
Definition typeinfo:94
std::type_info::before
bool before(const type_info &__arg) const noexcept
std::hash
Primary class template hash.
Definition functional_hash.h:106
std::type_index
Class type_index.
Definition typeindex:58