[Tinyos-help] [nesC] fan-out warnings

[Philip Levis]

On Nov 22, 2007, at 8:29 AM, Wouter Horré wrote:

> Hi,
>
> I have a wiring situation that looks like the folowing (simplified):
>
> generic component A           generic component A
>    (instance 1)                  (instance 2)
>         |                         |             interface I1<uint16_t>
>         +---> component B <-------+
>                    |                            interface I2
>                    +--> configuration C
>                          (contains component D providing I2)
>
> Compiling this results in the following warnings:
> nesc1: warning: calls to I2.method1 in B fan out, but there is no  
> combine
> function specified for the return type
> ...
>
> The generated app.c contains:
>
> inline static  void *B$I2$method1(message_t *arg_0xb78dd4e8, uint8_t
> arg_0xb78dd670){
> #line 17
>   void *result;
> #line 17
>
> #line 17
>   result = D$I2$method1(arg_0xb78dd4e8, arg_0xb78dd670);
> #line 17
>   result = D$I2$method1(arg_0xb78dd4e8, arg_0xb78dd670);
> #line 17
>
> #line 17
>   return result;
> #line 17
> }
>
> Why does nesC complain about a fan-out of interface I2? I believe  
> this should
> not happen and the generated app.c seems to support this believe  
> (the 2
> so-called fan-out calls are identical).
>
> Making component B generic makes the warnings dissappear, but it  
> duplicates
> the code of component B, which is not desired.
>
> Should I just ignore these warnings or is this a bug that is solved  
> in a more
> recent nesC compiler? I am using nesc 1.2.8a.
>

Are your component A's wiring B to C? If they are, then each time you  
instantiate an A, you wire B to C again.

Phil