From: Johannes Berg <johannes@sipsolutions.net>
To: John Garry <john.garry@huawei.com>, Joe Perches <joe@perches.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Kalle Valo <kvalo@codeaurora.org>,
jakub.kicinski@netronome.com, yamada.masahiro@socionext.com,
Arnd Bergmann <arnd@arndb.de>,
viro@zeniv.linux.org.uk,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: linux-wireless@vger.kernel.org, nbd@nbd.name
Subject: Re: Question on FIELD_PREP() for static array
Date: Thu, 11 Oct 2018 21:22:34 +0200 [thread overview]
Message-ID: <1539285754.4027.6.camel@sipsolutions.net> (raw)
In-Reply-To: <1539285190.4027.5.camel@sipsolutions.net>
On Thu, 2018-10-11 at 21:13 +0200, Johannes Berg wrote:
>
> However, I have another trick:
>
> #define __NLA_ENSURE(condition) (0 * sizeof(struct { unsigned int x:1 - 2*!(condition);}))
>
> or, in this context,
>
> #define BUILD_BUG_ON_RET_ZERO(cond) (0 * sizeof(struct { unsigned int x:1 - 2*!(condition);}))
Oops, I forgot to insert the second !, it must be
#define BUILD_BUG_ON_RET_ZERO(cond) (0 * sizeof(struct { unsigned int x:1 - 2*!!(condition);}))
johannes
prev parent reply other threads:[~2018-10-11 19:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 17:16 Question on FIELD_PREP() for static array John Garry
2018-10-10 17:33 ` Joe Perches
2018-10-10 18:13 ` Johannes Berg
2018-10-11 14:24 ` John Garry
2018-10-11 15:23 ` Johannes Berg
2018-10-11 16:16 ` John Garry
2018-10-11 17:26 ` John Garry
2018-10-11 19:13 ` Johannes Berg
2018-10-11 19:22 ` Johannes Berg [this message]
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