https://gcc.gnu.org/g:99135a19aad894b8f3d5372df0f94b14e2f42fb2
commit r16-8426-g99135a19aad894b8f3d5372df0f94b14e2f42fb2 Author: Jonathan Wakely <[email protected]> Date: Wed Apr 1 20:17:29 2026 +0100 libstdc++: Add Doxygen documentation to <version> libstdc++-v3/ChangeLog: * include/std/version: Add Doxygen documentation comment. Reviewed-by: Nathan Myers <[email protected]> Reviewed-by: Tomasz Kamiński <[email protected]> Diff: --- libstdc++-v3/include/std/version | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version index c6ac031f6b54..8ab9acc17a0a 100644 --- a/libstdc++-v3/include/std/version +++ b/libstdc++-v3/include/std/version @@ -23,8 +23,42 @@ // <http://www.gnu.org/licenses/>. /** @file version - * This is a Standard C++ Library file. You should @c \#include this file - * in your programs, rather than any of the @a *.h implementation files. + * 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
