Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain;
        charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\))
Subject: Re: [BlueZ PATCH] lib: fix variable-length array declarations in hci
 structures
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210831163545.3646157-1-pab@pabigot.com>
Date:   Tue, 31 Aug 2021 23:23:06 +0200
Cc:     linux-bluetooth@vger.kernel.org
Content-Transfer-Encoding: 8BIT
Message-Id: <3CBFA8E8-ABA1-495F-BFD4-A4E3CBC1E21B@holtmann.org>
References: <20210831163545.3646157-1-pab@pabigot.com>
To:     "Peter A. Bigot" <pab@pabigot.com>
Precedence: bulk

Hi Peter,

> Use of zero as the size for arrays as the last element of a structure
> is a GNU C extension, which as of GCC 10 produces diagnostics when
> values in the extended array are referenced.  Switch to the C99
> standard idiom for flexible array members, already in use in a few
> other headers.
> 
> Signed-off-by: Peter A. Bigot <pab@pabigot.com>
> ---
> 
> No changes from previous submission except the BlueZ subject prefix
> that I hope will get this into bluez.
> 
> lib/hci.h | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/hci.h b/lib/hci.h
> index 3382b87bf..a61568bce 100644
> --- a/lib/hci.h
> +++ b/lib/hci.h
> @@ -729,7 +729,7 @@ typedef struct {
> typedef struct {
> 	uint8_t		flt_type;
> 	uint8_t		cond_type;
> -	uint8_t		condition[0];
> +	uint8_t		condition[];
> } __attribute__ ((packed)) set_event_flt_cp;
> #define SET_EVENT_FLT_CP_SIZE 2

does this break any API assumptions? Since as long as libbluetooth exists these headers are API.

Regards

Marcel