1// -*- C++ -*- Libstdc++ version details header.
2
3// Copyright (C) 2018-2026 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 version
26 * This is a Standard C++ Library header. You should `#include` this header
27 * in your programs, rather than any of the `*.h` implementation files.
28 *
29 * The `<version>` header defines feature test macros that describe the
30 * supported features of the C++ standard library implementation being used.
31 * The macros that are defined, and their values, depend on compiler flags
32 * (usually `-std`, but others such as `-fcoroutines` and `-fno-aligned-new`
33 * can affect them).
34 *
35 * These macros can be used to conditionally enable or disable code:
36 *
37 * ```
38 * #include <version>
39 * #ifdef __cpp_lib_expected
40 * // std::expected is supported
41 * #endif
42 * ```
43 *
44 * The macro values indicate different levels of support, for example
45 * `__cpp_lib_expected == 202202L` means only the original feature set of
46 * `std::expected` is supported, while `__cpp_lib_expected == 202211L` means
47 * that the monadic functions such as `std::expected::and_then` are also
48 * supported.
49 *
50 * The list of macros defined in `<version>` and their meanings is given in
51 * the C++ standard committee's SD-6 document:
52 * https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
53 *
54 * `<version>` may also define non-standard, implementation-specific macros,
55 * such as libstdc++'s `_GLIBCXX_RELEASE`. However, the standard feature
56 * test macros should be preferred over depending on specific versions of any
57 * particular implementation.
58 *
59 * The `<version>` header was introduced in C++20, but libstdc++ provides it
60 * unconditionally. As documented in SD-6, some macros correspond to features
61 * in C++17 and earlier standards.
62 */
63
64#ifndef _GLIBCXX_VERSION_INCLUDED
65#define _GLIBCXX_VERSION_INCLUDED
66
67#ifdef _GLIBCXX_SYSHDR
68#pragma GCC system_header
69#endif
70
71#define __glibcxx_want_all
72#include <bits/version.h>
73
74#endif // _GLIBCXX_VERSION_INCLUDED
75