diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2025-07-18 11:35:00 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-11 15:22:17 +0100 |
| commit | e53bfe4530590f2832a96b21bd55e9416b4b1dc1 (patch) | |
| tree | bd0eec465a405c3cc35968a71523a5f4f75a6bd1 /include/linux | |
| parent | b9b5f45cc1b72953e1fe27bb32d9f3ace46ba4f2 (diff) | |
compiler_types.h: add "auto" as a macro for "__auto_type"
commit 2fb6915fa22dc5524d704afba58a13305dd9f533 upstream.
"auto" was defined as a keyword back in the K&R days, but as a storage
type specifier. No one ever used it, since it was and is the default
storage type for local variables.
C++11 recycled the keyword to allow a type to be declared based on the
type of an initializer. This was finally adopted into standard C in
C23.
gcc and clang provide the "__auto_type" alias keyword as an extension
for pre-C23, however, there is no reason to pollute the bulk of the
source base with this temporary keyword; instead define "auto" as a
macro unless the compiler is running in C23+ mode.
This macro is added in <linux/compiler_types.h> because that header is
included in some of the tools headers, wheres <linux/compiler.h> is
not as it has a bunch of very kernel-specific things in it.
[ Cc: stable to reduce potential backporting burden. ]
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/compiler_types.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 5c8aca9c3456..b63da6b03d33 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -5,6 +5,19 @@ #ifndef __ASSEMBLY__ /* + * C23 introduces "auto" as a standard way to define type-inferred + * variables, but "auto" has been a (useless) keyword even since K&R C, + * so it has always been "namespace reserved." + * + * Until at some future time we require C23 support, we need the gcc + * extension __auto_type, but there is no reason to put that elsewhere + * in the source code. + */ +#if __STDC_VERSION__ < 202311L +# define auto __auto_type +#endif + +/* * Skipped when running bindgen due to a libclang issue; * see https://github.com/rust-lang/rust-bindgen/issues/2244. */ |