#include <sys/types.h>
#include <sys/time.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>

void some_signal_handler(int si_number, siginfo_t *siginfo, void *bits)
{
}

int main(int argc,char *argv[])
{
	int r;
	struct itimerval it;
	sigset_t sigset;
	siginfo_t siginfo;

#if 0
#define THE_SIGACTION some_signal_handler
#else
#define THE_SIGACTION NULL
#endif

#if 0
	struct sigaction sa;

	memset(&sa,0,sizeof(sa));
	sa.sa_handler = SIG_IGN;
	sa.sa_sigaction = THE_SIGACTION;
	sigaction(SIGALRM,&sa,NULL);

	memset(&sa,0,sizeof(sa));
	sa.sa_handler = SIG_IGN;
	sa.sa_sigaction = THE_SIGACTION;
	sigaction(SIGWINCH,&sa,NULL);

	memset(&sa,0,sizeof(sa));
	sa.sa_handler = SIG_IGN;
	sa.sa_sigaction = THE_SIGACTION;
	sigaction(SIGCHLD,&sa,NULL);

	memset(&sa,0,sizeof(sa));
	sa.sa_handler = SIG_IGN;
	sa.sa_sigaction = THE_SIGACTION;
	sigaction(SIGHUP,&sa,NULL);
#endif

	sigemptyset(&sigset);
	sigaddset(&sigset,SIGALRM);
	sigaddset(&sigset,SIGWINCH);
	sigaddset(&sigset,SIGCHLD);
	sigaddset(&sigset,SIGHUP);
	sigprocmask(SIG_BLOCK,&sigset,NULL);

	memset(&it,0,sizeof(it));
	it.it_interval.tv_sec = 2;
	it.it_interval.tv_usec = 0;
	it.it_value.tv_sec = it.it_interval.tv_sec;
	it.it_value.tv_usec = it.it_interval.tv_usec;
	setitimer(ITIMER_REAL,&it,NULL);

	sigemptyset(&sigset);
	sigaddset(&sigset,SIGALRM);
	sigaddset(&sigset,SIGWINCH);
	sigaddset(&sigset,SIGCHLD);
	sigaddset(&sigset,SIGHUP);

	for (;;) {
		r = sigwaitinfo(&sigset,&siginfo);
		if (r > 0)
			printf("Received signal %u.\n",siginfo.si_signo);
	}

	exit(0);
}