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From:   David Howells <dhowells@redhat.com>
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To:     Jan Engelhardt <jengelh@inai.de>
Cc:     dhowells@redhat.com, linux-api@vger.kernel.org,
        linux-kbuild@vger.kernel.org, Coly Li <colyli@suse.de>,
        Kent Overstreet <kent.overstreet@gmail.com>,
        linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/11] UAPI: bcache: Fix use of embedded flexible array
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Date:   Tue, 09 Oct 2018 16:41:06 +0100
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Jan Engelhardt <jengelh@inai.de> wrote:

> """it [the array size expression] shall be a converted constant expression of
> type std::size_t and its value shall be greater than zero."""
> —http://eel.is/c++draft/dcl.array

Interesting.  You're not actually quoting the full sentence:

	If the constant-expression is present, it shall be a converted
	constant expression of type std​::​size_­t and its value shall be
	greater than zero.

This suggests that:

	__u64 ptr[]

is actually valid since:

	D1 [ constant-expressionopt ] attribute-specifier-seqopt

suggests that the part between the brackets is optional.

David