linux-kernel - Re: Exporting functions from vsprintf.c for Rust

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Message-Id: <D93S1SHPJDDU.INJ3UWZUM1UY@buenzli.dev>
Date: Fri, 11 Apr 2025 13:36:27 +0200
From: "Remo Senekowitsch" <remo@...nzli.dev>
To: "Petr Mladek" <pmladek@...e.com>
Cc: "Steven Rostedt" <rostedt@...dmis.org>, "Andy Shevchenko"
 <andriy.shevchenko@...ux.intel.com>, "Rasmus Villemoes"
 <linux@...musvillemoes.dk>, "Sergey Senozhatsky"
 <senozhatsky@...omium.org>, <linux-kernel@...r.kernel.org>
Subject: Re: Exporting functions from vsprintf.c for Rust

On Fri Apr 11, 2025 at 11:42 AM CEST, Petr Mladek wrote:
>
> Honestly, I do not have a good feeling about exporting the internal
> vsprintf() functions. They have a very specific semantic.
>
> Especially, they return pointer to the next-to-write character.
> And it might be even beyond the given *end pointer. It is because, for
> example, vsnprintf() returns the number of characters which would
> have been written to the buffer when it was big enough.
>
> Instead, I suggest to create a wrapper which would have a sane
> semantic and call scnprintf() internally. Something like:
>
> int fwnode_full_name_to_string(char *buf, size_t size,
> 			       struct fwnode_handle *fwnode)
> {
> 	return scnprintf(buf, size, "%pfwf", fwnode);
> }

That makes sense. I tried your suggestion and it works, thank you!

Best regards,
Remo