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 = 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==MONDAY) && (bitof(days,MONDAY)))
  MondayTask();

and this would also work:

if ((menuitem==MONDAY) && (ButtonPress()))
   bitof(days,MONDAY) = 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

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