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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Ian Abbott <abbotti@mev.co.uk>
Cc: "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
	"fmhess@users.sourceforge.net" <fmhess@users.sourceforge.net>,
	Ian Abbott <ian.abbott@mev.co.uk>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	H Hartley Sweeten <hartleys@visionengravers.com>
Subject: Re: [PATCH] staging: comedi: remove __user annotation inside of struct's
Date: Wed, 9 May 2012 17:19:20 +0300	[thread overview]
Message-ID: <20120509141920.GT22134@mwanda> (raw)
In-Reply-To: <4FAA4E85.6020305@mev.co.uk>

On Wed, May 09, 2012 at 12:01:25PM +0100, Ian Abbott wrote:
> Are there any handy macros for casting pointers to __user pointers,
> something like
> 
> #define _user(p) ((typeof(*(p)) __user *)(p))
> 
> but preferably without the repeated expansion of 'p' in case of
> side-effects?

typeof() doesn't have side effects.

#include <stdio.h>

int main(void)
{
	int x = 0;
	typeof(x++) y;

	printf("%d\n", x);

	return 0;
}

regards,
dan carpenter

  reply	other threads:[~2012-05-09 14:16 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-08 23:41 [PATCH] staging: comedi: remove __user annotation inside of struct's H Hartley Sweeten
2012-05-08 23:55 ` H Hartley Sweeten
2012-05-09 10:20   ` Ian Abbott
2012-05-09 10:31     ` Dan Carpenter
2012-05-09 11:01       ` Ian Abbott
2012-05-09 14:19         ` Dan Carpenter [this message]
2012-05-10 11:05           ` Ian Abbott
2012-05-09 14:24     ` gregkh
2012-05-09 15:52       ` H Hartley Sweeten
2012-05-09 15:56         ` gregkh
2012-05-09 16:03           ` H Hartley Sweeten
2012-05-09 16:41           ` H Hartley Sweeten
2012-05-09 20:42             ` gregkh

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