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DateWed, 21 Sep 2005 15:49:05 +0800
Fromliyu <>
SubjectA pettiness question.
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
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