[alsa-devel] [PATCH] ASoC: nau8825: jack connection decision with different insertion logic

[John Hsu]

On 7/1/2016 11:57 PM, Mark Brown wrote:
> On Thu, Jun 30, 2016 at 03:51:51PM +0800, John Hsu wrote:
>
>   
>> Yes, it'll be more readable. I have a question. Why to add !! in
>> front of bit wise operation? What does it mean?
>>     
>
> It's redundant in almost all cases.  It translates an integer value
> into a 0/1 value (so if you've got a value of 2 it'll end up as 1) by
> doing a double not.  This very rarely matters unless you're storing the
> value in an integer and comparing it to 1 to check for truth, otherwise
> C will translate any non-zero value into true in any logic context.
>   

Thank you for the explanation. I get the purpose now and will change
the expression of function for clear intent.