RES: RES: passing parameters to task

[Wendell Pereira da Silva]

Oh.. .sorry..


1)      Change to (struct complex_task_parameters *)

2)      Use it as a member of structure dynamically allocated (by means of -> operator). Example:
printk(“foo = %s\n, p->foo);

--Wendell.

De: Luca Cinquepalmi [mailto:cinquepalmi at planetek.it]
Enviada em: segunda-feira, 17 de setembro de 2012 10:18
Para: Wendell Pereira da Silva
Cc: Mathew Benson; rtems-users at rtems.org
Assunto: Re: RES: passing parameters to task

Thank you Wendell, that's exactly what I mean. I have two question for you.

1) In
rtems_task mytask(rtems_task_argument arg)
{
   struct complex_task_parameters* p;

   p = (complex_task_parameters *)arg;

   while(true)
   {
      //use parameters in p
      //....
   }
}

I have a type error in p = (complex_task_parameters *)arg;
Is complex_task_parameters type correct?

2) How can I use parameters in while cycle? How can I refer to "foo" for example?

     Thanks a lot again!

    Luca


Il 17/09/2012 14.35, Wendell Pereira da Silva ha scritto:
Hi Luca,

Mathew, please, may I post an example?
:-)

rtems_task mytask(rtems_task_argument arg);

(…)

struct complex_task_parameters
{
   uint32_t ui;  // first parameter...
   uint16_t usi; // second parameter...
   const char* foo;  // another parameter...
}

rtems_task Init(rtems_task_argument arg)
{
   rtems_id tid;
   struct complex_task_parameters* p_task_param;

   // allocate and initialize parameters
   p_task_param = calloc(1, sizeof(*p_task_param));
   p_task_param->ui = 1;
   p_task_param->usi = 0x1000;
   p_task_param->foo = "test...";

   // create the task as usual
   rtems_task_create(..., &tid);

   // now pass the parameter to the task;
   // use typecast to make the compiler happy.
   rtems_task_start(tid, mytask, (rtems_task_argument)p_task_param);


}


rtems_task mytask(rtems_task_argument arg)
{
   struct complex_task_parameters* p;

   p = (complex_task_parameters *)arg;

   while(true)
   {
      //use parameters in p
      //....
   }
}

Hope it helps.

--Wendell.


De: rtems-users-bounces at rtems.org<mailto:rtems-users-bounces at rtems.org> [mailto:rtems-users-bounces at rtems.org] Em nome de Luca Cinquepalmi
Enviada em: segunda-feira, 17 de setembro de 2012 07:20
Para: Mathew Benson
Cc: rtems-users at rtems.org<mailto:rtems-users at rtems.org>
Assunto: Re: passing parameters to task

I understand your suggestion... is there any example I could view?

    Luca

Il 17/09/2012 12.18, Mathew Benson ha scritto:
The same way you would with a POSIX pthread create call.  Just malloc a struct with your multiple parameters, set your parameters, and pass the reference of your struct to the function.  In your task entry point, cast the argument to a pointer to your struct and pull your parameters out.

Sent from my Amiga 1000

On Sep 17, 2012, at 4:35 AM, Luca Cinquepalmi <cinquepalmi at planetek.it<mailto:cinquepalmi at planetek.it>> wrote:
Hi all,
I would like to know if is it possible to pass more than one argument to a single task...
At the moment I only use this syntax when I define a task

rtems_task Test_task(rtems_task_argument unused)

How can I declare and define a more parameters dependent task?
Thanks a lot.

    Luca



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