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From: liyu <liyu@ccoss.com.cn>
To: LKML <linux-kernel@vger.kernel.org>
Subject: A pettiness question.
Date: Wed, 21 Sep 2005 15:49:05 +0800	[thread overview]
Message-ID: <43311071.8070706@ccoss.com.cn> (raw)

Hi, All.
   
    I found there are use double operator ! continuously sometimes in 
kernel.
e.g:

    static inline int is_page_cache_freeable(struct page *page)
    {
        return page_count(page) - !!PagePrivate(page) == 2;
    }

    Who would like tell me why write like above?
   
  
    Thanks in advanced.


Liyu

             reply	other threads:[~2005-09-21  7:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-21  7:49 liyu [this message]
2005-09-21  8:00 ` A pettiness question Ustyugov Roman
2005-09-21  8:57   ` Eyal Lebedinsky
2005-09-21  9:01   ` Fawad Lateef
2005-09-21  9:30     ` Andrea Arcangeli
2005-09-23  2:36       ` Vadim Lobanov
2005-09-21 15:08   ` Randy.Dunlap
2005-09-21 19:11 ` Bill Davidsen
  -- strict thread matches above, loose matches on Subject: below --
2005-09-21 19:46 Nick Warne
2005-09-21 20:05 ` Vadim Lobanov
2005-09-22  7:10   ` Helge Hafting
2005-09-22 12:21     ` Steven Rostedt
2005-09-22 14:40       ` linux-os (Dick Johnson)
2005-09-22  2:43 ` Fawad Lateef
     [not found] <4PiLw-2yn-25@gated-at.bofh.it>
     [not found] ` <4Pj4M-3as-1@gated-at.bofh.it>
     [not found]   ` <4PtnM-1oW-55@gated-at.bofh.it>
     [not found]     ` <4Pynh-fp-1@gated-at.bofh.it>
2005-09-25 14:38       ` Bodo Eggert

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