#include <signal.h>
#include <stdio.h>
#include <stdlib.h> 	/*exit()*/
#include <unistd.h>  	/*sleep()*/

/*Zähler*/
volatile sig_atomic_t count = 0;

/*Signal-Handler*/
void handler(int sig, siginfo_t* info, void* unused){
	/*Signalnummer ausgeben*/
	printf("Got signal %d.\n", info->si_signo);
	/*Signal code auslesen*/
	if(info->si_code==SI_USER) 
		puts("The signal was send by kill()\n");
	
	count++;
}


int main(int argc, char* argv[]){
	
	/*Struct fuer sigaction()*/
	struct sigaction act;
	/*Dieses flag zeigt an, dass der erweiterte Signal-Handler verwendet werden soll*/
	act.sa_flags = SA_SIGINFO;
	/*Handler-Funktion setzen*/
	act.sa_sigaction = handler;	
	/*Handler fuer SIGUSR1 setzen*/
	if(sigaction(SIGUSR1, &act, NULL)<0) exit(1);
	
	/*...*/
	while(1) {
		sleep(5);
		printf("%d\n", count);
		
		if(count == 2) break;
	}
	
	return 0;
}