Re: what does it use two "!!"

Ben Wu writes:

Dear All： 1> I found some placeuse two "!!", what's means if(button->gpio != INVALID_GPIO) state = !!((gpio_get_value(button->gpio) ? 1 : 0) ^ button->active_low); else state = !!button->adc_state;

if a = 1010011 then !a = 0 and !!a = 1 if a = 000000 then !a = 1 !! = 0 basically it means if a is non-zero then make a = exactly 1, else leave it at zero.

2> is there some MSN group to study linux kernel or discuss it ?

don't know, but it would be ironic.

Thanks and Best Regards

Ben Wu

MSN:crayben@yahoo.cn

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