libstdc++-v3/include/std/version

// -*- C++ -*- Libstdc++ version details header.

// Copyright (C) 2018-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
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// any later version.

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// 3.1, as published by the Free Software Foundation.

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/** @file version
 *  This is a Standard C++ Library header.  You should `#include` this header
 *  in your programs, rather than any of the `*.h` implementation files.
 *
 * The `<version>` header defines feature test macros that describe the
 * supported features of the C++ standard library implementation being used.
 * The macros that are defined, and their values, depend on compiler flags
 * (usually `-std`, but others such as `-fcoroutines` and `-fno-aligned-new`
 * can affect them).
 *
 * These macros can be used to conditionally enable or disable code:
 *
 * ```
 * #include <version>
 * #ifdef __cpp_lib_expected
 *   // std::expected is supported
 * #endif
 * ```
 *
 * The macro values indicate different levels of support, for example
 * `__cpp_lib_expected == 202202L` means only the original feature set of
 * `std::expected` is supported, while `__cpp_lib_expected == 202211L` means
 * that the monadic functions such as `std::expected::and_then` are also
 * supported.
 *
 * The list of macros defined in `<version>` and their meanings is given in
 * the C++ standard committee's SD-6 document:
 * https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
 *
 * `<version>` may also define non-standard, implementation-specific macros,
 * such as libstdc++'s `_GLIBCXX_RELEASE`.  However, the standard feature
 * test macros should be preferred over depending on specific versions of any
 * particular implementation.
 *
 * The `<version>` header was introduced in C++20, but libstdc++ provides it
 * unconditionally. As documented in SD-6, some macros correspond to features
 * in C++17 and earlier standards.
 */

#ifndef _GLIBCXX_VERSION_INCLUDED
#define _GLIBCXX_VERSION_INCLUDED

#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif

#define __glibcxx_want_all
#include <bits/version.h>

#endif // _GLIBCXX_VERSION_INCLUDED