The same rules for atomic still apply -- you only need atomic sections
if the data is accessed in async commands/events.
(Of course, you could still have races regardless if you access the
data across tasks in multiple components, but that's pretty clear
already.)
Cory
On 5/8/06, Aditya Bhave <[EMAIL PROTECTED]> wrote:
Yes the shared header file approach def works. I have included three such
header files in various components in my project and it seems to be working
smoothly. Just make sure to include the access to the shared data within
atomic statements to avoid race conditions.
On 5/9/06, Michael Schippling <[EMAIL PROTECTED]> wrote:
> I couldn't make externs work between components either...
>
> So I have used an interface in each component that takes a pointer
> to the variable in question and saves it locally. Each component
> then does an indirect access to the variable through the pointer.
>
> e.g.:
>
> in comp1 --
> long stuff;
>
> setup()
> {
> call comp2.setVariable( &stuff );
> }
>
> in comp2 --
> long *stuffp;
>
> setVariable( long *p )
> {
> // save pointer
> stuffp = p;
>
> // set variable to something
> *stuffp = 0xDADABABE;
> }
>
>
> However it has occurred to me that one should be able to do it via
> a shared header file, and I just tried it. This actually compiles
> and looking at the app.c output it seems ok, but I don't know if it
> really works because I haven't run the code...
>
> in header.h --
> #ifndef DEFED
> uint16_t monstate;
> #define DEFED
> #endif // DEFED
>
> extern uint16_t monstate;
>
> in each component --
>
> includes header;
> ....
>
> implementation
> {
> // use "global" variable
> monstate = 0xBEEF;
> }
>
>
> If you try the header method, let me know how it goes...
> MS
>
>
> [EMAIL PROTECTED] wrote:
> > hi,
> >
> > I m trying how ti share a variable between two components. I m using
> > global variable concept, but not working. Did anyone like this or any
> > other method is there?
> >
> > Thanks,
> > kiran.
> >
> > _______________________________________________
> > Tinyos-help mailing list
> > [email protected]
> >
https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> _______________________________________________
> Tinyos-help mailing list
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>
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>
--
regards,
Aditya Bhave
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