Thread: Signal question

Hi

I want to catch a signal and continue the program. But when I catch it, my signal handler takes the control and program terminates after the signal handler returns.

Here is the code

Code:

struct itimerval it;

static void sig_handler(int sig)
{
	printf("Signal\n");
}

int main()
{
	signal(SIGALRM,sig_handler);
	
	it.it_value.tv_sec=1;
	it.it_value.tv_usec=0;

	setitimer(ITIMER_REAL,&it,0);

	sleep(10);	
	return 0;
}

I want to print screen "Signal" continuously when a signal is caugth (so, print "Signal" once in a second).

How can I do this?

Thanks...

Hi

I rewrite the code with sigaction, thanks for warning me about it.

Actually the problem is using sleep() to waste time (APPLICATION USAGE section - http://www.opengroup.org/onlinepubs/009695399/functions/sigaction.html)! If I use some other method to keep the process running, the signal is caught every time. I also need to set timer each time a signal is caught. This code behaves as a want

Code:

struct itimerval it;

long unsigned int fibonacci (unsigned int n)
{
 .......
}

static void sig_handler(int sig)
{
        printf("Signal\n");
        setitimer(ITIMER_REAL,&it,0);
}

int main()
{
        struct sigaction sa;

        sa.sa_handler = sig_handler;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_RESTART;

        sigaction(SIGALRM,&sa,NULL);

        it.it_value.tv_sec=1;
        it.it_value.tv_usec=0;

       setitimer(ITIMER_REAL,&it,0);

        fibonacci(45);
        return 0;
}