From: Daniel Thompson <daniel@riscstar.com>
To: Alejandro Colomar <alx@kernel.org>
Cc: Martin Uecker <uecker@tugraz.at>,
Christopher Bazley <chris.bazley.wg14@gmail.com>,
Alex Celeste <alexg.nvfp@gmail.com>,
Joseph Myers <josmyers@redhat.com>,
Aaron Ballman <aaron@aaronballman.com>,
Douglas McIlroy <douglas.mcilroy@dartmouth.edu>,
Bruno Haible <bruno@clisp.org>, Paul Eggert <eggert@cs.ucla.edu>,
Florian Weimer <fweimer@redhat.com>,
Jonathan Corbet <corbet@lwn.net>, Kees Cook <kees@kernel.org>,
Eric Biggers <ebiggers@kernel.org>,
Ard Biesheuvel <ardb@kernel.org>,
Daniel Thompson <danielt@kernel.org>,
Daniel Lundin <daniel.lundin.mail@gmail.com>,
"Valentin V. Bartenev" <vbartenev@gmail.com>,
Andrew Clayton <andrew@digital-domain.net>,
"Brian W. Kernighan" <bwk@cs.princeton.edu>,
"G. Branden Robinson" <branden@debian.org>,
"Basil L. Contovounesios" <basil@contovou.net>,
"Jason A. Donenfeld" <jason@zx2c4.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
onf <onf@disroot.org>, Rich Felker <dalias@libc.org>,
linux-hardening@vger.kernel.org
Subject: Re: [RFC v3 5/6] alx-0081r2 - array parameters of 0 elements
Date: Wed, 28 Jan 2026 10:14:23 +0000 [thread overview]
Message-ID: <aXnhf9uAvyJbQfcn@aspen.lan> (raw)
In-Reply-To: <aXdiyLn3vxV2P807@devuan>
On Mon, Jan 26, 2026 at 01:49:16PM +0100, Alejandro Colomar wrote:
> Proposed wording
> Based on N3685.
>
> 6.7.7.3 Array declarators
> @@ Constraints, p1
> In addition to optional type qualifiers and the keyword static,
> the [ and ] can delimit an expression or *.
> If they delimit an expression,
> called the array length expression,
> the expression shall have an integer type.
> If the expression is a constant expression,
> -it shall have a value greater than zero.
> +it shall have a nonnegative value.
> +An array length expression
> +that is a constant expression with value zero
> +shall appear only in
> +a declaration of a function parameter with an array type,
> +and then only in the outermost array type derivation.
This change did not have any motivating example within the discussion.
Providing a motivational example showing why it is useful to allow array
parameters whose constant length is zero would be good.
Daniel.
next prev parent reply other threads:[~2026-01-28 10:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aXZM5O2mU2e3LJBJ@devuan>
2026-01-26 12:48 ` [RFC v3 0/6] Improve function parameters in ISO C2y Alejandro Colomar
2026-01-26 12:48 ` [RFC v3 1/6] alx-0077r3 - disallow function parameters of function type Alejandro Colomar
2026-01-26 12:48 ` [RFC v3 2/6] alx-0076r3 - incompatible array parameters Alejandro Colomar
2026-01-26 12:48 ` [RFC v3 3/6] alx-0078r2 - [static n] shouldn't access more than n elements Alejandro Colomar
2026-01-28 9:54 ` Daniel Thompson
2026-01-28 15:14 ` Alejandro Colomar
2026-01-26 12:49 ` [RFC v3 4/6] alx-0079r2 - [static n] == non-null [n] Alejandro Colomar
2026-01-26 12:49 ` [RFC v3 5/6] alx-0081r2 - array parameters of 0 elements Alejandro Colomar
2026-01-28 10:14 ` Daniel Thompson [this message]
2026-01-28 15:21 ` Alejandro Colomar
2026-01-26 12:49 ` [RFC v3 6/6] alx-0080r1 - [static] without array length expression Alejandro Colomar
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