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From: Rusty Russell <rusty@rustcorp.com.au>
To: Boaz Harrosh <bharrosh@panasas.com>
Subject: Re: [PATCH 5/5 ver2] debug: BUILD_BUG_ON: error on non-const expressions
Date: Thu, 2 Oct 2008 15:35:35 +1000
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Cc: Ingo Molnar <mingo@elte.hu>, "David S. Miller" <davem@davemloft.net>,
       Ivo van Doorn <IvDoorn@gmail.com>,
       "John W. Linville" <linville@tuxdriver.com>,
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On Wednesday 03 September 2008 01:57:31 Boaz Harrosh wrote:
> +#define BUILD_BUG_ON(e) \
> +       do { struct {int:-!!(e); } x __maybe_unused;} while(0)

Why did you hate the void cast again?  Simplest should 
be "(void)BUILD_BUG_ON_ZERO(e)".  But if not, it seems to me that it's 
cleaner to do:

#define BUILD_BUG_ON(e) \
	do { } while(BUILD_BUG_ON_ZERO(e))

No chance of the compiler emitting unused vars.

Cheers,
Rusty.