Bob Blick escreveu:
> On Wed, 25 Nov 2009 14:26:01 +0800, "Justin Richards"
> <justin.richards@gmail.com> said:
>   =

>> Thanks Bob,
>>
>> struggling to understand here but I guess would use it like
>>
>> if (bitof(days.day,tm_wday))
>> {
>>     do something
>> }
>>
>> and if tm_wday =3D 1 (monday)
>>
>> it expand to
>>
>> if(((bitv *)&(days.day))->b1)
>>
>> and now I am lost.  What is bitv and how can I break it down further.
>>
>> Cheers Justin
>> 2009/11/25 Bob Blick <bobblick@ftml.net>
>>
>>     =

>>> You might be able to use this to help you access bits:
>>>
>>> #define _paste(a,b)         a##b
>>> #define bitof(var,num)      (((bitv *)&(var))->_paste(b,num))
>>>       =

>
> I didn't write it, but it's just a preprocessor construct that allows
> you to treat bits within a variable similarly to an array and you don't
> need to use separate getters and setters. So you can do something like
> this:
>
> if ((today=3D=3DMONDAY) && (bitof(days,MONDAY)))
>   MondayTask();
>
> and this would also work:
>
> if ((menuitem=3D=3DMONDAY) && (ButtonPress()))
>    bitof(days,MONDAY) =3D 1;
>
> I was really sleepy when I saw your first post so I don't remember what
> it was exactly you were doing, but having this as an option for you may
> work out somewhere.
>
> Cheerful regards,
>
> Bob
>   =


It appears that Justin needs the bit-index to be variable. If so, the
macro won't work because the macro is expanded at compile time and need
the bit number to be a constant.


Best regards,

Isaac
__________________________________________________
Fa=E7a liga=E7=F5es para outros computadores com o novo Yahoo! Messenger =

http://br.beta.messenger.yahoo.com/ =


-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist