SIS in "real time"

[Joel Sherrill]

Hi

I  made some changes to test3.c so it can be compiled for RTEMS or
any "normal" POSIX host like Linux. I avoided the rtems timespec
addition method.

I think this does what you expect on Linux but didn't try it on RTEMS.

FWIW this is a good minimal example of how a program can support
being built for Linux and RTEMS. For bigger examples, I prefer the RTEMS
configuration and Init thread to be in a separate file. I think the psx
reporting
examples do that.

--joel

On Fri, Apr 9, 2021 at 12:45 PM Heinz Junkes <junkes at fhi-berlin.mpg.de>
wrote:

> Jiri, Joel, thanks for your answers.
>
> @Joel: I was wondering that rtems-examples in psx_example_3 does not wait
> 3 seconds.
>
> I made a curious observation:
>
> in the original code:
>
>    clock_gettime( CLOCK_REALTIME, &timeout );
>    timeout.tv_sec += 3;
>    timeout.tv_nsec = 0;
>    printf("The task is coming to enter in a timed wait\n");
>    pthread_cond_timedwait(&cond, &mutex, &timeout);
>
>
> I then inserted some printfs and found that the "3" is added to the nsec’s.
>
> Then I added the rtems-timespec-helpers routines, but get the same
> behavior:
>
>
> void * print_hello(void * arg)
> {
>   struct timespec now, timeout;
>   rtems_timespec_set(&timeout, 3, 0);
>
>   printf("<child>: Hello World! task with max priority \n");
>   clock_gettime( CLOCK_REALTIME, &now );
> printf("now tv_sec = %d, tv_nsec = %d\n", now.tv_sec, now.tv_nsec);
>   rtems_timespec_add_to(&timeout, &now);
> printf("timeout tv_sec = %d, tv_nsec = %d\n", timeout.tv_sec,
> timeout.tv_nsec);
>   printf("The task is coming to enter in a timed wait\n");
>   pthread_cond_timedwait(&cond, &mutex, &timeout);
>   printf("The task is coming out from the timed wait \n");
>   return NULL;
> }
>
> program output:
>
> <main> Enter in the main
> Creating first task
> <child>: Hello World! task with max priority
> now tv_sec = 4766459, tv_nsec = 567993600
> timeout tv_sec = 4766459, tv_nsec = 567993603
> The task is coming to enter in a timed wait
> The task is coming out from the timed wait
> First Task created
> Creating second task
>  <child>: Hello World! Task with lowest priority Second task created
> <main> Out of the main
>
> If I now swap the arguments in the set-function , i.e. instead of
>  rtems_timespec_set(&timeout, 3, 0);
>
>  rtems_timespec_set(&timeout, 0, 3);
>
> it looks as it should
>
> <child>: Hello World! task with max priority
> now tv_sec = 10766729, tv_nsec = 567993600
> timeout tv_sec = 10766732, tv_nsec = 567993600
> The task is coming to enter in a timed wait
> The task is coming out from the timed wait
> First Task created
> Creating second task
>  <child>: Hello World! Task with lowest priority Second task created
> <main> Out of the main
>
> But still no timed wait  recognizable :-(
>
> Heinz
>
>
>
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