Hi Cédric,

you missed a few minor things - first of all, you need to initialize the struct sigevent prior to passing it to 
timer_create(). Use SIGEV_SIGNAL_INIT to do so (see below).

Further, the struct itimerspec provided to timer_settime must be completely initialized, and its  it_value  member must 
be != 0.0, otherwise the time won't run.

See below for a revised (working) version of your app. I removed the clock semaphore; you can just use  sigwait()  in 
your thread to synchronize on the signal. Saves a lot of overhead, too.  Oh, and BTW - you don't need to reattach a 
signal handler within itself (like you do in some other OSes), so calling  signal()  in your  timer_handler()  function 
isn't required.

Hope this helps.

Cheers,
- Thomas

#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <semaphore.h>
#include <pthread.h>
#include <time.h>


sem_t		startStopSem;


void *tSubRate_1( void * cookie ) {
	sigset_t  sigs;
	int  sig;
	int	i = 0; /*just for test and debug*/

	while (1) {
		sigemptyset( &sigs );
		sigaddset( &sigs, SIGRTMIN );
		sigwait( &sigs, &sig );
		printf("Hello...\n");
		i += 1;
		if ( i > 5 )
			sem_post( &startStopSem );
	}
}

int main(int argc, char *argv[]) {
	pthread_t  tSubRate1Desc;
	struct itimerspec  paramTimer;
	struct sigevent  event;
	timer_t  timerDesc;
	int  status;

	status = sem_init(&startStopSem, NULL, 0);
	if (status != 0)
		printf("Error creating semaphore : %d\n", status);

	status = pthread_create( &tSubRate1Desc, NULL, tSubRate_1, NULL );
	if (status != 0)
		printf ("Error creating task : %d\n", status);

	SIGEV_SIGNAL_INIT( &event, SIGRTMIN );

  	status = timer_create( CLOCK_REALTIME, &event, &timerDesc );
  	if (status != 0)
  		printf("Error creating timer : %d\n", status);
  
	paramTimer.it_value.tv_sec = 1;
	paramTimer.it_value.tv_nsec = 0;
	paramTimer.it_interval.tv_sec = 1;
	paramTimer.it_interval.tv_nsec = 0;

  	timer_settime( timerDesc, 0, ¶mTimer, NULL );
	sem_wait( &startStopSem );
	printf("End...\n");

	return EXIT_SUCCESS;
}

> -----Ursprüngliche Nachricht-----
> Von: Cédric Schaffter [mailto:community-noreply@qnx.com]
> Gesendet: 19 September 2008 11:02
> An: general-community
> Betreff: Re: Periodic tasks creation
> 
> 
> Hi List,
> 
> I get another problem with my application. I would like to 
> generate a signal with a timer, and synchronize one thread 
> with this timer.
> 
> Actually, it's like if my timer_handler can't catch the signal. 
> 
> Did I miss some instructions or did something wrong?
> Thanks.
> 
> /*************************************************************
> ********************/
> #include <stdlib.h>
> #include <stdio.h>
> #include <signal.h>
> #include <semaphore.h>
> #include <pthread.h>
> #include <time.h>
> 
> sem_t rtClockSem;
> sem_t startStopSem;
> pthread_t tSubRate1Desc;
> struct itimerspec paramTimer;
> struct sigevent event;
> timer_t timerDesc;
> int i = 0; /*just for test and debug*/
> 
> void * tSubRate_1(void * cookie)
> {
>   while (1) {
>  	sem_wait(&rtClockSem);
> 	printf("Hello...\n");
> 	i += 1;
> 	if (i > 5)
> 		sem_post(&startStopSem);
> 
>   }
> }
> void timer_handler(int sig){
> 	int status;
> 	if (sig == SIGRTMIN){
> 		status = sem_post(&rtClockSem);	
> 		if (status != 0)
> 			printf ("Semaphore error : %d\n", status);
> 		
> 		/*signal association*/
> 		signal(SIGRTMIN, timer_handler);
>   		if (status != 0)
>   			printf("error while signal association \n");
> 	}
> }
> 
> int main(int argc, char *argv[]) {
> 	int status;
> 	status = sem_init(&startStopSem, NULL, 0);
>  	if (status != 0)
>    ...