Процессы в линуксе на с++

#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#define TIMEOUT 10
 
int f1(int), f2(int), f3(int);
 
int pid0, pid1, pid2;
 
void main(void)
 
{ setpgrp();
 
pid0 = getpid();
 
pid1 = fork();
 
if (pid1 == 0) /* process 1 */
 
{ signal(SIGUSR1, f1);
 
pid1 = getpid();
 
pid2 = fork();
 
if (pid2 < 0 ) puts("Fork error");
 
if (pid2 > 0) for(;;);
 
else /* process 2 */
 
{ signal(SIGUSR2, f2);
 
pid2 = getpid();
 
kill(pid1,SIGUSR1);
 
for (;;);
 
}}
 
else /* process 0 */
 
{ signal(SIGALRM, f3);
 
alarm(TIMEOUT);
 
pause();
 
}
 
exit(0);
 
}
 
int f1(int signum)
 
{ signal(SIGUSR1, f1);
 
printf("Process 1 (%d) has got a signal from process 2 (%d)\n",pid1,pid2);
 
sleep(1);
 
kill(pid2, SIGUSR2);
 
return 0;
 
}
 
int f2(int signum)
 
{ signal(SIGUSR2, f2);
 
printf("Process 2 (%d) has got a signal from process 1 (%d)\n",pid2,pid1);
 
sleep(1);
 
kill(pid1, SIGUSR1);
 
return 0;
 
}
 
int f3(int signum)
 
{ printf("End of job - %d\n", pid0);
 
kill(0, SIGKILL);
 
return 0;
 
}

signal(SIGUSR1, &f1);