Re: [PATCH 1/2] tracing: work around -Wmissing-format-attribute warning

[Arnd Bergmann]

On Wed, Jun 3, 2026, at 14:49, Rasmus Villemoes wrote:
> On Wed, Jun 03 2026, "Arnd Bergmann" <arnd@xxxxxxxx> wrote:
>> On Wed, Jun 3, 2026, at 09:15, Rasmus Villemoes wrote:

> I don't remember what minimum gcc we currently require, but gcc 9
> introduced another attribute that is apperently meant for cases like
> this: 'copy'.

The minimum version is gcc-8.

> This seems to build:
>...
> +int __vsnprintf(char *buf, size_t size, const char *fmt_str, va_list args)
> +       __alias(vsnprintf) __attribute__((__copy__(vsnprintf)));
> +
>
> That at least should handle any future "gcc knows this-or-that about the
> vsnprintf function". But I don't know if clang supports that copy
> mechanism or if the minimum supported gcc is too old.

clang-22 and gcc-8 don't like the attribute, but also don't complain
about the other mismatched attributes, so simply using the __copy()
macro we already have will work on all currently supported
compilers and likely all future ones as well.

      Arnd