[PATCH] include: let BitIsOn() return a boolean value.

[Pat Kane]

Okay, with that info and if you could make the macro something like this:

 #define BitIsOn(ptr, bit) (!!(((BYTE *) (ptr))[(bit)>>3] & (1 <<
((bit) & 7))))  /* !! converts to boolean */

then:

Reviewed: Pat Kane <pekane52 at gmail.com>

Pat
----
P.S.  I love C, it is my favorite assembly code.  -- PEK


On Wed, Nov 24, 2010 at 4:28 PM, Peter Hutterer
<peter.hutterer at who-t.net> wrote:
> On Wed, Nov 24, 2010 at 12:18:16PM -0600, Pat Kane wrote:
>> What the deal with the "!!" operator?  I read it as a double logical negation.
>> A NOOP,  does it have some useful side effect?
>
> http://stackoverflow.com/questions/1406604/what-does-the-operator-double-exclamation-point-mean-in-javascript
> is the first link I found.
>
> yes, I used to think it was dirty too, but I've grown to like it.
>
> Cheers,
>  Peter
>>
>> On Wed, Nov 24, 2010 at 10:30 AM, walter harms <wharms at bfs.de> wrote:
>> >
>> >
>> > Am 24.11.2010 07:25, schrieb Keith Packard:
>> >> On Wed, 24 Nov 2010 14:40:11 +1000, Peter Hutterer <peter.hutterer at who-t.net> wrote:
>> >>
>> >>> -#define BitIsOn(ptr, bit) (((BYTE *) (ptr))[(bit)>>3] & (1 << ((bit) & 7)))
>> >>> +#define BitIsOn(ptr, bit) !!(((BYTE *) (ptr))[(bit)>>3] & (1 << ((bit) & 7)))
>> >>
>> >
>> > bit is checked to be less than 8 with "(bit) & 7" but only in the second statement.
>> > the linux kernel specifies them as inline code. maybe this is the way to go here also.
>> >
>> > re,
>> >  wh
>