Re: [Xenomai-main] Exiting the Xenomai emulation

[Fabrice TOMASI]

> Exit() does not work with the 1.1.1 posix.h, because the manual
> scheduling is done with SIGSTOP/SIGCONT. If you use posix.h from the
> CVS, the manual scheduling is done with POSIX condition variables, so
> that exit() should work correctly. The adaptation of the newer posix.h
> to the RTC driver should be as easy as for the older.
   Ok, I've upgraded the posix.h from the CVS as you said and simply 
replaced the posix_tick_timer() by the RTC driver.

> The only way I know to "cleanly" exit an application with pthreads, is
> to cancel all the running threads but the main thread, decrementing a
> counter in the "top" cleanup handler and signaling a condition variable
> when this counter reaches 0, which wakes up the main thread. 
> Unfortunately  you then have to be prepared, in each thread, to be
> canceled at any (cancelation) point. I would recommend to use this
> "clean" exit only for leaks research with valgrind/kcachegrind. The rest
> of the time, relying on the OS is simpler and faster.
>  
   Yes, the leaks research is the only reason for us to use a clean 
exit (the research is done with ccmalloc)....So, we can't call the 
exit() function. In the new posix.h, the clean exit can't be called 
because in the main() function, there is an infinite loop:
   for(;;)
       pause();
  
   posix_cleanup_application();
   posix_cleanup_interface();
   posix_cleanup_nanokernel();

   exit(EXIT_SUCCESS);

So, how can the posix_cleanup_*() be called ??


   By the way, I've got another problem with this new version. When 
calling xnpod_start_thread(), it first locks a mutex 
(xnmutex_lock(&kmutex)), then it calls the xnarch_init_thread() 
function. In this function, the new thread is created by 
pthread_create(), but for a reason I can't explain myself, this pthread 
library call never returns when the scheduling is set to SCHED_FIFO (it 
works fine with SCHED_OTHER). As a consequence, the mutex is never 
unlocked hence the posix_thread_trampoline() and the posix_tick_timer() 
are blocked too and the simulation is freezed !! Do you know why this 
behaviour occurs ?


            Fabrice