[RFC v3 6/6] alx-0080r1 - [static] without array length expression

[Alejandro Colomar <alx@kernel.org>]

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Name
	alx-0080r1 - [static] without array length expression

Principles
	-  Keep the language small and simple

Category
	Language; array parameters.

Author
	Alejandro Colomar <alx@kernel.org>

	Cc: Martin Uecker <uecker@tugraz.at>
	Acked-by: Doug McIlroy
	Acked-by: Andrew Clayton <ac@sigsegv.uk>

History
	<https://www.alejandro-colomar.es/src/alx/alx/std/wg14/alx-0080.git/>

	r0 (2026-01-25):
	-  Initial draft.

	r1 (2026-01-26):
	-  Acked-by.
	-  tfix

Abstract
	'static' in [static n] means that the argument shall be
	non-null.  That is entirely independent of the length of the
	array parameter, so it doesn't make sense requiring the length
	to be specified.  Lift that restriction.

Discussion
	While the standard, for a long time, claimed that 'static' in
	[static n] was about the length of the array, it is well known
	that this is only true in paper.  In practice, programmers use
	[n] with that meaning.

	'static' in [static n] has a different meaning (see also
	alx-0079): it says that the argument shall be non-null.

See also
	<https://www.alejandro-colomar.es/src/alx/alx/std/wg14/alx-0079.git/>
	alx-0079 ("[static n] == non-null [n]")
	alx-0079 should be applied before alx-0080.  Otherwise, the
	semantics would be undefined.

Comments
	On 2026-01-25T18:19:02-0500, Douglas McIlroy wrote:
	> All six proposals look eminently reasonable.  They simplify
	> the language and remove surprises.  I suspect these proposals
	> will invalidate very few existing programs.  In any event, the
	> required corrections will improve the legibility and
	> maintainability of such programs.
	>
	> Doug McIlroy

	---

	On 2026-01-26T02:01:16+0000, Alex Celeste wrote:
	> Like Martin - these all seem eminently reasonable to me.

Proposed wording
	Based on N3685.

    6.7.7.1  Declarators :: General
	@@ Syntax, p1
	+array-qualifier-list:
	+	<b>static</b>(opt) type-qualifier-list
	+	type-qualifier-list <b>static</b>
	+
	+array-length-declarator:
	+	assignment-expression
	+	<b>*</b>
	+
	 array-declarator:
	-	direct-declarator <b>[</b> type-qualifier-list(opt) assignment-expression(opt) <b>]</b>
	-	direct-declarator <b>[ static</b> type-qualifier-list(opt) assignment-expression <b>]</b>
	-	direct-declarator <b>[</b> type-qualifier-list <b>static</b> assignment-expression <b>]</b>
	-	direct-declarator <b>[</b> type-qualifier-list(opt) <b>* ]</b>
	+	direct-declarator <b>[</b> array-qualifier-list(opt) array-length-declarator(opt) <b>]</b>

-- 
<https://www.alejandro-colomar.es>

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