Dear all,
here is another small demo... this time of a periodic thread in POSIX.
It works under Xenomai, but it fails under Posix Real-Time.
The reason of the failure is the SIGUSR1 not being blocked by the main
thread. If in main() the comments below the note // REMOVE THE COMMENTS
BELOW are removed, then the signal is masked also in the main(), and as
a result the POSIX version works.
The question I have is if the behavior in Xenomai (that is, not failing
like the POSIX counterpart) is correct or not...
bye
Paolo
--
Evidence S.R.L. - Paolo Gai, CEO
http://www.evidence.eu.com Tel: +39 0587 274823 Fax: +39 0587 291904
#include stdlib.h
#include stdio.h
#include time.h
#include errno.h
#include signal.h
#include unistd.h
#include pthread.h
void abort_perror(const char *msg)
{
perror(msg);
exit(1);
}
void *my_periodic_thread (void *cookie)
{
struct itimerspec its;
struct sigevent sig;
sigset_t blocked;
siginfo_t si;
timer_t mytimer;
int i;
/* create a timer that will be used to periodically send a signal */
sig.sigev_notify = SIGEV_SIGNAL;
sig.sigev_signo = SIGUSR1;
sig.sigev_value.sival_ptr = sig;
if(timer_create(CLOCK_REALTIME, sig, mytimer))
abort_perror(timer_create);
/* block the signal used by the timer */
sigemptyset(blocked);
sigaddset(blocked, SIGUSR1);
pthread_sigmask(SIG_BLOCK, blocked, NULL);
/* set the periodic timer */
its.it_value.tv_sec = 0;
its.it_value.tv_nsec = 4000; /* 40 ms */
its.it_interval.tv_sec = 0;
its.it_interval.tv_nsec = 2000; /* 20 ms */;
if(timer_settime(mytimer, 0, its, NULL))
abort_perror(timer_settime);
printf(periodic thread started...\n);
for (i=0; i40; i++) {
while (sigwaitinfo(blocked, si) == -1 errno == EINTR);
/* The thread body */
printf(%d\n,i);
}
printf(...periodic thread end!\n);
timer_delete(mytimer);
return NULL;
}
int main()
{
pthread_t mythread;
pthread_attr_t myattr;
struct sched_param myparam;
void *returnvalue;
sigset_t blocked;
/* block the signal used by the timer */
// REMOVE THE COMMENTS BELOW
// sigemptyset(blocked);
// sigaddset(blocked, SIGUSR1);
// pthread_sigmask(SIG_BLOCK, blocked, NULL);
/* initializes the thread attribute */
pthread_attr_init(myattr);
pthread_attr_setinheritsched(myattr, PTHREAD_EXPLICIT_SCHED);
pthread_attr_setschedpolicy(myattr, SCHED_FIFO);
myparam.sched_priority = 3;
pthread_attr_setschedparam(myattr, myparam);
printf(starting a periodic thread...\n);
if (pthread_create(mythread, myattr, my_periodic_thread, NULL))
abort_perror(pthread_create);
pthread_attr_destroy(myattr);
/* wait the end of the thread we just created */
pthread_join(mythread, returnvalue);
printf(ending main...\n);
return 0;
}
