position of task variable codes

[Joel Sherrill]

Eric Norum wrote:
> 
> On Friday, April 12, 2002, at 08:38 PM, Joe Black wrote:
> 
> >       Hi, all
> >
> >       Dose the position of rtems_task_variable_add must be in the task?
> 
> Yes, the rtems_task_variable_add directive tells RTEMS to add the
> specified variable to the task-switch context of the*calling* task.
> 
> >
> > -----------------------------------------------------------------------------------
> >
> >       my case:
> >               in init_task
> >               create task1
> >               call rtems_task_variable_add to add task1's variable
> >               start task1
> >
> >               create task2 (with the same priority of task1)
> >               call rtems_task_variable_add to add task2's variable
> >               start task2
> >
> 
> The above code adds the variable to the `init' task twice, so task1 and
> task2 still use the `global' (not per-task) value of the variable.
> 
> >               delete init_task and task1 run
> >
> >               printf task1's variable
> >
> >               suspend task1 and task2 run
> >
> >               printf task2's variable
> >
> >               resume task1
> >
> >               suspend task2 and task1 run
> >
> >               in task1, printf its variable, it failed :(
> >
> >               resume task2 and suspend task1
> >
> >               in task2, printf its variable, failed too
> >
> > -----------------------------------------------------------------------------------
> >
> >       I can guarantee the parameters passed to rtems_task_variable_add
> > are OK in the case above.
> >       If I put the rtems_task_variable_add in task1 or task2, it works well
> >
> >       Could anyone tell me how I can resolve the problem? 3x.
> 
> It sounds like you have already solved it.  To add a variable to a
> task's context you must call rtems_task_variable_add from that task.
>  From then on any changes made to that variable by that task will be
> local to the task.

Joe.. did you look for this information in the user's manual?  If you
did
and didn't find it, please submit a patch. :)

> --
> Eric Norum <eric.norum at usask.ca>
> Department of Electrical Engineering
> University of Saskatchewan
> Saskatoon, Canada.
> Phone: (306) 966-5394   FAX:   (306) 966-5407

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
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